pcap-linux.c revision 214518
126175Sfenner/* 275107Sfenner * pcap-linux.c: Packet capture interface to the Linux kernel 326175Sfenner * 475107Sfenner * Copyright (c) 2000 Torsten Landschoff <torsten@debian.org> 575107Sfenner * Sebastian Krahmer <krahmer@cs.uni-potsdam.de> 6127664Sbms * 775107Sfenner * License: BSD 8127664Sbms * 975107Sfenner * Redistribution and use in source and binary forms, with or without 1075107Sfenner * modification, are permitted provided that the following conditions 1175107Sfenner * are met: 12127664Sbms * 1375107Sfenner * 1. Redistributions of source code must retain the above copyright 1475107Sfenner * notice, this list of conditions and the following disclaimer. 1575107Sfenner * 2. Redistributions in binary form must reproduce the above copyright 1675107Sfenner * notice, this list of conditions and the following disclaimer in 1775107Sfenner * the documentation and/or other materials provided with the 1875107Sfenner * distribution. 1975107Sfenner * 3. The names of the authors may not be used to endorse or promote 2075107Sfenner * products derived from this software without specific prior 2175107Sfenner * written permission. 22127664Sbms * 2375107Sfenner * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 2475107Sfenner * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 2575107Sfenner * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 26190225Srpaulo * 27190225Srpaulo * Modifications: Added PACKET_MMAP support 28190225Srpaulo * Paolo Abeni <paolo.abeni@email.it> 29190225Srpaulo * 30190225Srpaulo * based on previous works of: 31190225Srpaulo * Simon Patarin <patarin@cs.unibo.it> 32190225Srpaulo * Phil Wood <cpw@lanl.gov> 33214518Srpaulo * 34214518Srpaulo * Monitor-mode support for mac80211 includes code taken from the iw 35214518Srpaulo * command; the copyright notice for that code is 36214518Srpaulo * 37214518Srpaulo * Copyright (c) 2007, 2008 Johannes Berg 38214518Srpaulo * Copyright (c) 2007 Andy Lutomirski 39214518Srpaulo * Copyright (c) 2007 Mike Kershaw 40214518Srpaulo * Copyright (c) 2008 G��bor Stefanik 41214518Srpaulo * 42214518Srpaulo * All rights reserved. 43214518Srpaulo * 44214518Srpaulo * Redistribution and use in source and binary forms, with or without 45214518Srpaulo * modification, are permitted provided that the following conditions 46214518Srpaulo * are met: 47214518Srpaulo * 1. Redistributions of source code must retain the above copyright 48214518Srpaulo * notice, this list of conditions and the following disclaimer. 49214518Srpaulo * 2. Redistributions in binary form must reproduce the above copyright 50214518Srpaulo * notice, this list of conditions and the following disclaimer in the 51214518Srpaulo * documentation and/or other materials provided with the distribution. 52214518Srpaulo * 3. The name of the author may not be used to endorse or promote products 53214518Srpaulo * derived from this software without specific prior written permission. 54214518Srpaulo * 55214518Srpaulo * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 56214518Srpaulo * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 57214518Srpaulo * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 58214518Srpaulo * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 59214518Srpaulo * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 60214518Srpaulo * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 61214518Srpaulo * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 62214518Srpaulo * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 63214518Srpaulo * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 64214518Srpaulo * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 65214518Srpaulo * SUCH DAMAGE. 6626175Sfenner */ 67127664Sbms 6826175Sfenner#ifndef lint 69127664Sbmsstatic const char rcsid[] _U_ = 70214518Srpaulo "@(#) $Header: /tcpdump/master/libpcap/pcap-linux.c,v 1.164 2008-12-14 22:00:57 guy Exp $ (LBL)"; 7126175Sfenner#endif 7226175Sfenner 7375107Sfenner/* 7475107Sfenner * Known problems with 2.0[.x] kernels: 7575107Sfenner * 7675107Sfenner * - The loopback device gives every packet twice; on 2.2[.x] kernels, 7775107Sfenner * if we use PF_PACKET, we can filter out the transmitted version 7875107Sfenner * of the packet by using data in the "sockaddr_ll" returned by 7975107Sfenner * "recvfrom()", but, on 2.0[.x] kernels, we have to use 8075107Sfenner * PF_INET/SOCK_PACKET, which means "recvfrom()" supplies a 8175107Sfenner * "sockaddr_pkt" which doesn't give us enough information to let 8275107Sfenner * us do that. 8375107Sfenner * 8475107Sfenner * - We have to set the interface's IFF_PROMISC flag ourselves, if 8575107Sfenner * we're to run in promiscuous mode, which means we have to turn 8675107Sfenner * it off ourselves when we're done; the kernel doesn't keep track 8775107Sfenner * of how many sockets are listening promiscuously, which means 8875107Sfenner * it won't get turned off automatically when no sockets are 8975107Sfenner * listening promiscuously. We catch "pcap_close()" and, for 9075107Sfenner * interfaces we put into promiscuous mode, take them out of 9175107Sfenner * promiscuous mode - which isn't necessarily the right thing to 9275107Sfenner * do, if another socket also requested promiscuous mode between 9375107Sfenner * the time when we opened the socket and the time when we close 9475107Sfenner * the socket. 9598530Sfenner * 9698530Sfenner * - MSG_TRUNC isn't supported, so you can't specify that "recvfrom()" 9798530Sfenner * return the amount of data that you could have read, rather than 9898530Sfenner * the amount that was returned, so we can't just allocate a buffer 9998530Sfenner * whose size is the snapshot length and pass the snapshot length 10098530Sfenner * as the byte count, and also pass MSG_TRUNC, so that the return 10198530Sfenner * value tells us how long the packet was on the wire. 10298530Sfenner * 10398530Sfenner * This means that, if we want to get the actual size of the packet, 10498530Sfenner * so we can return it in the "len" field of the packet header, 10598530Sfenner * we have to read the entire packet, not just the part that fits 10698530Sfenner * within the snapshot length, and thus waste CPU time copying data 10798530Sfenner * from the kernel that our caller won't see. 10898530Sfenner * 10998530Sfenner * We have to get the actual size, and supply it in "len", because 11098530Sfenner * otherwise, the IP dissector in tcpdump, for example, will complain 11198530Sfenner * about "truncated-ip", as the packet will appear to have been 11298530Sfenner * shorter, on the wire, than the IP header said it should have been. 11375107Sfenner */ 11426175Sfenner 11575107Sfenner 116214518Srpaulo#define _GNU_SOURCE 117214518Srpaulo 11875107Sfenner#ifdef HAVE_CONFIG_H 11975107Sfenner#include "config.h" 12039291Sfenner#endif 12126175Sfenner 12226175Sfenner#include <errno.h> 123214518Srpaulo#include <stdio.h> 12426175Sfenner#include <stdlib.h> 125214518Srpaulo#include <ctype.h> 12675107Sfenner#include <unistd.h> 12775107Sfenner#include <fcntl.h> 12826175Sfenner#include <string.h> 129214518Srpaulo#include <limits.h> 13075107Sfenner#include <sys/socket.h> 13175107Sfenner#include <sys/ioctl.h> 13275107Sfenner#include <sys/utsname.h> 133190225Srpaulo#include <sys/mman.h> 134214518Srpaulo#include <linux/if.h> 13575107Sfenner#include <netinet/in.h> 13675107Sfenner#include <linux/if_ether.h> 13775107Sfenner#include <net/if_arp.h> 138190225Srpaulo#include <poll.h> 139214518Srpaulo#include <dirent.h> 14026175Sfenner 14198530Sfenner/* 142190225Srpaulo * Got Wireless Extensions? 143190225Srpaulo */ 144190225Srpaulo#ifdef HAVE_LINUX_WIRELESS_H 145190225Srpaulo#include <linux/wireless.h> 146214518Srpaulo#endif /* HAVE_LINUX_WIRELESS_H */ 147190225Srpaulo 148214518Srpaulo/* 149214518Srpaulo * Got libnl? 150214518Srpaulo */ 151214518Srpaulo#ifdef HAVE_LIBNL 152214518Srpaulo#include <linux/nl80211.h> 153214518Srpaulo 154214518Srpaulo#include <netlink/genl/genl.h> 155214518Srpaulo#include <netlink/genl/family.h> 156214518Srpaulo#include <netlink/genl/ctrl.h> 157214518Srpaulo#include <netlink/msg.h> 158214518Srpaulo#include <netlink/attr.h> 159214518Srpaulo#endif /* HAVE_LIBNL */ 160214518Srpaulo 161190225Srpaulo#include "pcap-int.h" 162190225Srpaulo#include "pcap/sll.h" 163190225Srpaulo#include "pcap/vlan.h" 164190225Srpaulo 165190225Srpaulo#ifdef HAVE_DAG_API 166190225Srpaulo#include "pcap-dag.h" 167190225Srpaulo#endif /* HAVE_DAG_API */ 168190225Srpaulo 169190225Srpaulo#ifdef HAVE_SEPTEL_API 170190225Srpaulo#include "pcap-septel.h" 171190225Srpaulo#endif /* HAVE_SEPTEL_API */ 172190225Srpaulo 173214518Srpaulo#ifdef HAVE_SNF_API 174214518Srpaulo#include "pcap-snf.h" 175214518Srpaulo#endif /* HAVE_SNF_API */ 176214518Srpaulo 177190225Srpaulo#ifdef PCAP_SUPPORT_USB 178190225Srpaulo#include "pcap-usb-linux.h" 179190225Srpaulo#endif 180190225Srpaulo 181190225Srpaulo#ifdef PCAP_SUPPORT_BT 182190225Srpaulo#include "pcap-bt-linux.h" 183190225Srpaulo#endif 184190225Srpaulo 185214518Srpaulo#ifdef PCAP_SUPPORT_CAN 186214518Srpaulo#include "pcap-can-linux.h" 187214518Srpaulo#endif 188214518Srpaulo 189190225Srpaulo/* 19098530Sfenner * If PF_PACKET is defined, we can use {SOCK_RAW,SOCK_DGRAM}/PF_PACKET 19198530Sfenner * sockets rather than SOCK_PACKET sockets. 19298530Sfenner * 19398530Sfenner * To use them, we include <linux/if_packet.h> rather than 19498530Sfenner * <netpacket/packet.h>; we do so because 19598530Sfenner * 19698530Sfenner * some Linux distributions (e.g., Slackware 4.0) have 2.2 or 19798530Sfenner * later kernels and libc5, and don't provide a <netpacket/packet.h> 19898530Sfenner * file; 19998530Sfenner * 20098530Sfenner * not all versions of glibc2 have a <netpacket/packet.h> file 20198530Sfenner * that defines stuff needed for some of the 2.4-or-later-kernel 20298530Sfenner * features, so if the system has a 2.4 or later kernel, we 20398530Sfenner * still can't use those features. 20498530Sfenner * 20598530Sfenner * We're already including a number of other <linux/XXX.h> headers, and 20698530Sfenner * this code is Linux-specific (no other OS has PF_PACKET sockets as 20798530Sfenner * a raw packet capture mechanism), so it's not as if you gain any 20898530Sfenner * useful portability by using <netpacket/packet.h> 20998530Sfenner * 21098530Sfenner * XXX - should we just include <linux/if_packet.h> even if PF_PACKET 21198530Sfenner * isn't defined? It only defines one data structure in 2.0.x, so 21298530Sfenner * it shouldn't cause any problems. 21398530Sfenner */ 214127664Sbms#ifdef PF_PACKET 21598530Sfenner# include <linux/if_packet.h> 21626175Sfenner 21775107Sfenner /* 21898530Sfenner * On at least some Linux distributions (for example, Red Hat 5.2), 21998530Sfenner * there's no <netpacket/packet.h> file, but PF_PACKET is defined if 22098530Sfenner * you include <sys/socket.h>, but <linux/if_packet.h> doesn't define 22175107Sfenner * any of the PF_PACKET stuff such as "struct sockaddr_ll" or any of 22275107Sfenner * the PACKET_xxx stuff. 22375107Sfenner * 22475107Sfenner * So we check whether PACKET_HOST is defined, and assume that we have 22575107Sfenner * PF_PACKET sockets only if it is defined. 22675107Sfenner */ 22775107Sfenner# ifdef PACKET_HOST 22875107Sfenner# define HAVE_PF_PACKET_SOCKETS 229190225Srpaulo# ifdef PACKET_AUXDATA 230190225Srpaulo# define HAVE_PACKET_AUXDATA 231190225Srpaulo# endif /* PACKET_AUXDATA */ 23275107Sfenner# endif /* PACKET_HOST */ 233190225Srpaulo 234190225Srpaulo 235190225Srpaulo /* check for memory mapped access avaibility. We assume every needed 236190225Srpaulo * struct is defined if the macro TPACKET_HDRLEN is defined, because it 237190225Srpaulo * uses many ring related structs and macros */ 238190225Srpaulo# ifdef TPACKET_HDRLEN 239190225Srpaulo# define HAVE_PACKET_RING 240190225Srpaulo# ifdef TPACKET2_HDRLEN 241190225Srpaulo# define HAVE_TPACKET2 242190225Srpaulo# else 243190225Srpaulo# define TPACKET_V1 0 244190225Srpaulo# endif /* TPACKET2_HDRLEN */ 245190225Srpaulo# endif /* TPACKET_HDRLEN */ 24698530Sfenner#endif /* PF_PACKET */ 24775107Sfenner 24875107Sfenner#ifdef SO_ATTACH_FILTER 24975107Sfenner#include <linux/types.h> 25075107Sfenner#include <linux/filter.h> 25126175Sfenner#endif 25226175Sfenner 253190225Srpaulo#ifndef HAVE_SOCKLEN_T 25475107Sfennertypedef int socklen_t; 25575107Sfenner#endif 25626175Sfenner 25775107Sfenner#ifndef MSG_TRUNC 25898530Sfenner/* 25998530Sfenner * This is being compiled on a system that lacks MSG_TRUNC; define it 26098530Sfenner * with the value it has in the 2.2 and later kernels, so that, on 26198530Sfenner * those kernels, when we pass it in the flags argument to "recvfrom()" 26298530Sfenner * we're passing the right value and thus get the MSG_TRUNC behavior 26398530Sfenner * we want. (We don't get that behavior on 2.0[.x] kernels, because 26498530Sfenner * they didn't support MSG_TRUNC.) 26598530Sfenner */ 26698530Sfenner#define MSG_TRUNC 0x20 26775107Sfenner#endif 26875107Sfenner 269127664Sbms#ifndef SOL_PACKET 270127664Sbms/* 271127664Sbms * This is being compiled on a system that lacks SOL_PACKET; define it 272127664Sbms * with the value it has in the 2.2 and later kernels, so that we can 273127664Sbms * set promiscuous mode in the good modern way rather than the old 274127664Sbms * 2.0-kernel crappy way. 275127664Sbms */ 276127664Sbms#define SOL_PACKET 263 277127664Sbms#endif 278127664Sbms 27975107Sfenner#define MAX_LINKHEADER_SIZE 256 28075107Sfenner 281127664Sbms/* 282127664Sbms * When capturing on all interfaces we use this as the buffer size. 28375107Sfenner * Should be bigger then all MTUs that occur in real life. 28475107Sfenner * 64kB should be enough for now. 28575107Sfenner */ 28675107Sfenner#define BIGGER_THAN_ALL_MTUS (64*1024) 28775107Sfenner 28875107Sfenner/* 289190225Srpaulo * Prototypes for internal functions and methods. 29075107Sfenner */ 291127664Sbmsstatic void map_arphrd_to_dlt(pcap_t *, int, int); 292190225Srpaulo#ifdef HAVE_PF_PACKET_SOCKETS 293190225Srpaulostatic short int map_packet_type_to_sll_type(short int); 294190225Srpaulo#endif 295190225Srpaulostatic int pcap_activate_linux(pcap_t *); 296190225Srpaulostatic int activate_old(pcap_t *); 297190225Srpaulostatic int activate_new(pcap_t *); 298190225Srpaulostatic int activate_mmap(pcap_t *); 299190225Srpaulostatic int pcap_can_set_rfmon_linux(pcap_t *); 300127664Sbmsstatic int pcap_read_linux(pcap_t *, int, pcap_handler, u_char *); 30175107Sfennerstatic int pcap_read_packet(pcap_t *, pcap_handler, u_char *); 302146768Ssamstatic int pcap_inject_linux(pcap_t *, const void *, size_t); 303127664Sbmsstatic int pcap_stats_linux(pcap_t *, struct pcap_stat *); 304127664Sbmsstatic int pcap_setfilter_linux(pcap_t *, struct bpf_program *); 305162012Ssamstatic int pcap_setdirection_linux(pcap_t *, pcap_direction_t); 306190225Srpaulostatic void pcap_cleanup_linux(pcap_t *); 30775107Sfenner 308190225Srpaulounion thdr { 309190225Srpaulo struct tpacket_hdr *h1; 310190225Srpaulo struct tpacket2_hdr *h2; 311190225Srpaulo void *raw; 312190225Srpaulo}; 313190225Srpaulo 314190225Srpaulo#ifdef HAVE_PACKET_RING 315190225Srpaulo#define RING_GET_FRAME(h) (((union thdr **)h->buffer)[h->offset]) 316190225Srpaulo 317190225Srpaulostatic void destroy_ring(pcap_t *handle); 318190225Srpaulostatic int create_ring(pcap_t *handle); 319190225Srpaulostatic int prepare_tpacket_socket(pcap_t *handle); 320190225Srpaulostatic void pcap_cleanup_linux_mmap(pcap_t *); 321190225Srpaulostatic int pcap_read_linux_mmap(pcap_t *, int, pcap_handler , u_char *); 322190225Srpaulostatic int pcap_setfilter_linux_mmap(pcap_t *, struct bpf_program *); 323190225Srpaulostatic int pcap_setnonblock_mmap(pcap_t *p, int nonblock, char *errbuf); 324190225Srpaulostatic int pcap_getnonblock_mmap(pcap_t *p, char *errbuf); 325214518Srpaulostatic void pcap_oneshot_mmap(u_char *user, const struct pcap_pkthdr *h, 326214518Srpaulo const u_char *bytes); 327190225Srpaulo#endif 328190225Srpaulo 32975107Sfenner/* 33075107Sfenner * Wrap some ioctl calls 33175107Sfenner */ 33275107Sfenner#ifdef HAVE_PF_PACKET_SOCKETS 33375107Sfennerstatic int iface_get_id(int fd, const char *device, char *ebuf); 33475107Sfenner#endif 33575107Sfennerstatic int iface_get_mtu(int fd, const char *device, char *ebuf); 33675107Sfennerstatic int iface_get_arptype(int fd, const char *device, char *ebuf); 33775107Sfenner#ifdef HAVE_PF_PACKET_SOCKETS 33875107Sfennerstatic int iface_bind(int fd, int ifindex, char *ebuf); 339214518Srpaulo#ifdef IW_MODE_MONITOR 340190225Srpaulostatic int has_wext(int sock_fd, const char *device, char *ebuf); 341214518Srpaulo#endif /* IW_MODE_MONITOR */ 342214518Srpaulostatic int enter_rfmon_mode(pcap_t *handle, int sock_fd, 343190225Srpaulo const char *device); 344214518Srpaulo#endif /* HAVE_PF_PACKET_SOCKETS */ 34575107Sfennerstatic int iface_bind_old(int fd, const char *device, char *ebuf); 34675107Sfenner 34775107Sfenner#ifdef SO_ATTACH_FILTER 348214518Srpaulostatic int fix_program(pcap_t *handle, struct sock_fprog *fcode, 349214518Srpaulo int is_mapped); 35075107Sfennerstatic int fix_offset(struct bpf_insn *p); 35198530Sfennerstatic int set_kernel_filter(pcap_t *handle, struct sock_fprog *fcode); 35298530Sfennerstatic int reset_kernel_filter(pcap_t *handle); 35398530Sfenner 35498530Sfennerstatic struct sock_filter total_insn 35598530Sfenner = BPF_STMT(BPF_RET | BPF_K, 0); 35698530Sfennerstatic struct sock_fprog total_fcode 35798530Sfenner = { 1, &total_insn }; 35875107Sfenner#endif 35975107Sfenner 36075107Sfennerpcap_t * 361190225Srpaulopcap_create(const char *device, char *ebuf) 36226175Sfenner{ 363190225Srpaulo pcap_t *handle; 36498530Sfenner 365214518Srpaulo /* 366214518Srpaulo * A null device name is equivalent to the "any" device. 367214518Srpaulo */ 368214518Srpaulo if (device == NULL) 369214518Srpaulo device = "any"; 370214518Srpaulo 371127664Sbms#ifdef HAVE_DAG_API 372127664Sbms if (strstr(device, "dag")) { 373190225Srpaulo return dag_create(device, ebuf); 374127664Sbms } 375127664Sbms#endif /* HAVE_DAG_API */ 376127664Sbms 377147894Ssam#ifdef HAVE_SEPTEL_API 378147894Ssam if (strstr(device, "septel")) { 379190225Srpaulo return septel_create(device, ebuf); 380147894Ssam } 381147894Ssam#endif /* HAVE_SEPTEL_API */ 38226175Sfenner 383214518Srpaulo#ifdef HAVE_SNF_API 384214518Srpaulo handle = snf_create(device, ebuf); 385214518Srpaulo if (strstr(device, "snf") || handle != NULL) 386214518Srpaulo return handle; 387214518Srpaulo 388214518Srpaulo#endif /* HAVE_SNF_API */ 389214518Srpaulo 390190225Srpaulo#ifdef PCAP_SUPPORT_BT 391190225Srpaulo if (strstr(device, "bluetooth")) { 392190225Srpaulo return bt_create(device, ebuf); 393190225Srpaulo } 394190225Srpaulo#endif 395147894Ssam 396214518Srpaulo#ifdef PCAP_SUPPORT_CAN 397214518Srpaulo if (strstr(device, "can") || strstr(device, "vcan")) { 398214518Srpaulo return can_create(device, ebuf); 399214518Srpaulo } 400214518Srpaulo#endif 401214518Srpaulo 402190225Srpaulo#ifdef PCAP_SUPPORT_USB 403214518Srpaulo if (strstr(device, "usbmon")) { 404190225Srpaulo return usb_create(device, ebuf); 405190225Srpaulo } 406190225Srpaulo#endif 407190225Srpaulo 408190225Srpaulo handle = pcap_create_common(device, ebuf); 409190225Srpaulo if (handle == NULL) 41075107Sfenner return NULL; 411190225Srpaulo 412190225Srpaulo handle->activate_op = pcap_activate_linux; 413190225Srpaulo handle->can_set_rfmon_op = pcap_can_set_rfmon_linux; 414190225Srpaulo return handle; 415190225Srpaulo} 416190225Srpaulo 417214518Srpaulo#ifdef HAVE_LIBNL 418214518Srpaulo/* 419214518Srpaulo * 420214518Srpaulo * If interface {if} is a mac80211 driver, the file 421214518Srpaulo * /sys/class/net/{if}/phy80211 is a symlink to 422214518Srpaulo * /sys/class/ieee80211/{phydev}, for some {phydev}. 423214518Srpaulo * 424214518Srpaulo * On Fedora 9, with a 2.6.26.3-29 kernel, my Zydas stick, at 425214518Srpaulo * least, has a "wmaster0" device and a "wlan0" device; the 426214518Srpaulo * latter is the one with the IP address. Both show up in 427214518Srpaulo * "tcpdump -D" output. Capturing on the wmaster0 device 428214518Srpaulo * captures with 802.11 headers. 429214518Srpaulo * 430214518Srpaulo * airmon-ng searches through /sys/class/net for devices named 431214518Srpaulo * monN, starting with mon0; as soon as one *doesn't* exist, 432214518Srpaulo * it chooses that as the monitor device name. If the "iw" 433214518Srpaulo * command exists, it does "iw dev {if} interface add {monif} 434214518Srpaulo * type monitor", where {monif} is the monitor device. It 435214518Srpaulo * then (sigh) sleeps .1 second, and then configures the 436214518Srpaulo * device up. Otherwise, if /sys/class/ieee80211/{phydev}/add_iface 437214518Srpaulo * is a file, it writes {mondev}, without a newline, to that file, 438214518Srpaulo * and again (sigh) sleeps .1 second, and then iwconfig's that 439214518Srpaulo * device into monitor mode and configures it up. Otherwise, 440214518Srpaulo * you can't do monitor mode. 441214518Srpaulo * 442214518Srpaulo * All these devices are "glued" together by having the 443214518Srpaulo * /sys/class/net/{device}/phy80211 links pointing to the same 444214518Srpaulo * place, so, given a wmaster, wlan, or mon device, you can 445214518Srpaulo * find the other devices by looking for devices with 446214518Srpaulo * the same phy80211 link. 447214518Srpaulo * 448214518Srpaulo * To turn monitor mode off, delete the monitor interface, 449214518Srpaulo * either with "iw dev {monif} interface del" or by sending 450214518Srpaulo * {monif}, with no NL, down /sys/class/ieee80211/{phydev}/remove_iface 451214518Srpaulo * 452214518Srpaulo * Note: if you try to create a monitor device named "monN", and 453214518Srpaulo * there's already a "monN" device, it fails, as least with 454214518Srpaulo * the netlink interface (which is what iw uses), with a return 455214518Srpaulo * value of -ENFILE. (Return values are negative errnos.) We 456214518Srpaulo * could probably use that to find an unused device. 457214518Srpaulo * 458214518Srpaulo * Yes, you can have multiple monitor devices for a given 459214518Srpaulo * physical device. 460214518Srpaulo*/ 461214518Srpaulo 462214518Srpaulo/* 463214518Srpaulo * Is this a mac80211 device? If so, fill in the physical device path and 464214518Srpaulo * return 1; if not, return 0. On an error, fill in handle->errbuf and 465214518Srpaulo * return PCAP_ERROR. 466214518Srpaulo */ 467190225Srpaulostatic int 468214518Srpauloget_mac80211_phydev(pcap_t *handle, const char *device, char *phydev_path, 469214518Srpaulo size_t phydev_max_pathlen) 470190225Srpaulo{ 471214518Srpaulo char *pathstr; 472214518Srpaulo ssize_t bytes_read; 473214518Srpaulo 474214518Srpaulo /* 475214518Srpaulo * Generate the path string for the symlink to the physical device. 476214518Srpaulo */ 477214518Srpaulo if (asprintf(&pathstr, "/sys/class/net/%s/phy80211", device) == -1) { 478214518Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 479214518Srpaulo "%s: Can't generate path name string for /sys/class/net device", 480214518Srpaulo device); 481214518Srpaulo return PCAP_ERROR; 482214518Srpaulo } 483214518Srpaulo bytes_read = readlink(pathstr, phydev_path, phydev_max_pathlen); 484214518Srpaulo if (bytes_read == -1) { 485214518Srpaulo if (errno == ENOENT || errno == EINVAL) { 486214518Srpaulo /* 487214518Srpaulo * Doesn't exist, or not a symlink; assume that 488214518Srpaulo * means it's not a mac80211 device. 489214518Srpaulo */ 490214518Srpaulo free(pathstr); 491214518Srpaulo return 0; 492214518Srpaulo } 493214518Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 494214518Srpaulo "%s: Can't readlink %s: %s", device, pathstr, 495214518Srpaulo strerror(errno)); 496214518Srpaulo free(pathstr); 497214518Srpaulo return PCAP_ERROR; 498214518Srpaulo } 499214518Srpaulo free(pathstr); 500214518Srpaulo phydev_path[bytes_read] = '\0'; 501214518Srpaulo return 1; 502214518Srpaulo} 503214518Srpaulo 504214518Srpaulostruct nl80211_state { 505214518Srpaulo struct nl_handle *nl_handle; 506214518Srpaulo struct nl_cache *nl_cache; 507214518Srpaulo struct genl_family *nl80211; 508214518Srpaulo}; 509214518Srpaulo 510214518Srpaulostatic int 511214518Srpaulonl80211_init(pcap_t *handle, struct nl80211_state *state, const char *device) 512214518Srpaulo{ 513214518Srpaulo state->nl_handle = nl_handle_alloc(); 514214518Srpaulo if (!state->nl_handle) { 515214518Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 516214518Srpaulo "%s: failed to allocate netlink handle", device); 517214518Srpaulo return PCAP_ERROR; 518214518Srpaulo } 519214518Srpaulo 520214518Srpaulo if (genl_connect(state->nl_handle)) { 521214518Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 522214518Srpaulo "%s: failed to connect to generic netlink", device); 523214518Srpaulo goto out_handle_destroy; 524214518Srpaulo } 525214518Srpaulo 526214518Srpaulo state->nl_cache = genl_ctrl_alloc_cache(state->nl_handle); 527214518Srpaulo if (!state->nl_cache) { 528214518Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 529214518Srpaulo "%s: failed to allocate generic netlink cache", device); 530214518Srpaulo goto out_handle_destroy; 531214518Srpaulo } 532214518Srpaulo 533214518Srpaulo state->nl80211 = genl_ctrl_search_by_name(state->nl_cache, "nl80211"); 534214518Srpaulo if (!state->nl80211) { 535214518Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 536214518Srpaulo "%s: nl80211 not found", device); 537214518Srpaulo goto out_cache_free; 538214518Srpaulo } 539214518Srpaulo 540214518Srpaulo return 0; 541214518Srpaulo 542214518Srpauloout_cache_free: 543214518Srpaulo nl_cache_free(state->nl_cache); 544214518Srpauloout_handle_destroy: 545214518Srpaulo nl_handle_destroy(state->nl_handle); 546214518Srpaulo return PCAP_ERROR; 547214518Srpaulo} 548214518Srpaulo 549214518Srpaulostatic void 550214518Srpaulonl80211_cleanup(struct nl80211_state *state) 551214518Srpaulo{ 552214518Srpaulo genl_family_put(state->nl80211); 553214518Srpaulo nl_cache_free(state->nl_cache); 554214518Srpaulo nl_handle_destroy(state->nl_handle); 555214518Srpaulo} 556214518Srpaulo 557214518Srpaulostatic int 558214518Srpauloadd_mon_if(pcap_t *handle, int sock_fd, struct nl80211_state *state, 559214518Srpaulo const char *device, const char *mondevice) 560214518Srpaulo{ 561214518Srpaulo int ifindex; 562214518Srpaulo struct nl_msg *msg; 563214518Srpaulo int err; 564214518Srpaulo 565214518Srpaulo ifindex = iface_get_id(sock_fd, device, handle->errbuf); 566214518Srpaulo if (ifindex == -1) 567214518Srpaulo return PCAP_ERROR; 568214518Srpaulo 569214518Srpaulo msg = nlmsg_alloc(); 570214518Srpaulo if (!msg) { 571214518Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 572214518Srpaulo "%s: failed to allocate netlink msg", device); 573214518Srpaulo return PCAP_ERROR; 574214518Srpaulo } 575214518Srpaulo 576214518Srpaulo genlmsg_put(msg, 0, 0, genl_family_get_id(state->nl80211), 0, 577214518Srpaulo 0, NL80211_CMD_NEW_INTERFACE, 0); 578214518Srpaulo NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, ifindex); 579214518Srpaulo NLA_PUT_STRING(msg, NL80211_ATTR_IFNAME, mondevice); 580214518Srpaulo NLA_PUT_U32(msg, NL80211_ATTR_IFTYPE, NL80211_IFTYPE_MONITOR); 581214518Srpaulo 582214518Srpaulo err = nl_send_auto_complete(state->nl_handle, msg); 583214518Srpaulo if (err < 0) { 584214518Srpaulo if (err == -ENFILE) { 585214518Srpaulo /* 586214518Srpaulo * Device not available; our caller should just 587214518Srpaulo * keep trying. 588214518Srpaulo */ 589214518Srpaulo nlmsg_free(msg); 590214518Srpaulo return 0; 591214518Srpaulo } else { 592214518Srpaulo /* 593214518Srpaulo * Real failure, not just "that device is not 594214518Srpaulo * available. 595214518Srpaulo */ 596214518Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 597214518Srpaulo "%s: nl_send_auto_complete failed adding %s interface: %s", 598214518Srpaulo device, mondevice, strerror(-err)); 599214518Srpaulo nlmsg_free(msg); 600214518Srpaulo return PCAP_ERROR; 601214518Srpaulo } 602214518Srpaulo } 603214518Srpaulo err = nl_wait_for_ack(state->nl_handle); 604214518Srpaulo if (err < 0) { 605214518Srpaulo if (err == -ENFILE) { 606214518Srpaulo /* 607214518Srpaulo * Device not available; our caller should just 608214518Srpaulo * keep trying. 609214518Srpaulo */ 610214518Srpaulo nlmsg_free(msg); 611214518Srpaulo return 0; 612214518Srpaulo } else { 613214518Srpaulo /* 614214518Srpaulo * Real failure, not just "that device is not 615214518Srpaulo * available. 616214518Srpaulo */ 617214518Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 618214518Srpaulo "%s: nl_wait_for_ack failed adding %s interface: %s", 619214518Srpaulo device, mondevice, strerror(-err)); 620214518Srpaulo nlmsg_free(msg); 621214518Srpaulo return PCAP_ERROR; 622214518Srpaulo } 623214518Srpaulo } 624214518Srpaulo 625214518Srpaulo /* 626214518Srpaulo * Success. 627214518Srpaulo */ 628214518Srpaulo nlmsg_free(msg); 629214518Srpaulo return 1; 630214518Srpaulo 631214518Srpaulonla_put_failure: 632214518Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 633214518Srpaulo "%s: nl_put failed adding %s interface", 634214518Srpaulo device, mondevice); 635214518Srpaulo nlmsg_free(msg); 636214518Srpaulo return PCAP_ERROR; 637214518Srpaulo} 638214518Srpaulo 639214518Srpaulostatic int 640214518Srpaulodel_mon_if(pcap_t *handle, int sock_fd, struct nl80211_state *state, 641214518Srpaulo const char *device, const char *mondevice) 642214518Srpaulo{ 643214518Srpaulo int ifindex; 644214518Srpaulo struct nl_msg *msg; 645214518Srpaulo int err; 646214518Srpaulo 647214518Srpaulo ifindex = iface_get_id(sock_fd, mondevice, handle->errbuf); 648214518Srpaulo if (ifindex == -1) 649214518Srpaulo return PCAP_ERROR; 650214518Srpaulo 651214518Srpaulo msg = nlmsg_alloc(); 652214518Srpaulo if (!msg) { 653214518Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 654214518Srpaulo "%s: failed to allocate netlink msg", device); 655214518Srpaulo return PCAP_ERROR; 656214518Srpaulo } 657214518Srpaulo 658214518Srpaulo genlmsg_put(msg, 0, 0, genl_family_get_id(state->nl80211), 0, 659214518Srpaulo 0, NL80211_CMD_DEL_INTERFACE, 0); 660214518Srpaulo NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, ifindex); 661214518Srpaulo 662214518Srpaulo err = nl_send_auto_complete(state->nl_handle, msg); 663214518Srpaulo if (err < 0) { 664214518Srpaulo if (err == -ENFILE) { 665214518Srpaulo /* 666214518Srpaulo * Device not available; our caller should just 667214518Srpaulo * keep trying. 668214518Srpaulo */ 669214518Srpaulo nlmsg_free(msg); 670214518Srpaulo return 0; 671214518Srpaulo } else { 672214518Srpaulo /* 673214518Srpaulo * Real failure, not just "that device is not 674214518Srpaulo * available. 675214518Srpaulo */ 676214518Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 677214518Srpaulo "%s: nl_send_auto_complete failed deleting %s interface: %s", 678214518Srpaulo device, mondevice, strerror(-err)); 679214518Srpaulo nlmsg_free(msg); 680214518Srpaulo return PCAP_ERROR; 681214518Srpaulo } 682214518Srpaulo } 683214518Srpaulo err = nl_wait_for_ack(state->nl_handle); 684214518Srpaulo if (err < 0) { 685214518Srpaulo if (err == -ENFILE) { 686214518Srpaulo /* 687214518Srpaulo * Device not available; our caller should just 688214518Srpaulo * keep trying. 689214518Srpaulo */ 690214518Srpaulo nlmsg_free(msg); 691214518Srpaulo return 0; 692214518Srpaulo } else { 693214518Srpaulo /* 694214518Srpaulo * Real failure, not just "that device is not 695214518Srpaulo * available. 696214518Srpaulo */ 697214518Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 698214518Srpaulo "%s: nl_wait_for_ack failed adding %s interface: %s", 699214518Srpaulo device, mondevice, strerror(-err)); 700214518Srpaulo nlmsg_free(msg); 701214518Srpaulo return PCAP_ERROR; 702214518Srpaulo } 703214518Srpaulo } 704214518Srpaulo 705214518Srpaulo /* 706214518Srpaulo * Success. 707214518Srpaulo */ 708214518Srpaulo nlmsg_free(msg); 709214518Srpaulo return 1; 710214518Srpaulo 711214518Srpaulonla_put_failure: 712214518Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 713214518Srpaulo "%s: nl_put failed deleting %s interface", 714214518Srpaulo device, mondevice); 715214518Srpaulo nlmsg_free(msg); 716214518Srpaulo return PCAP_ERROR; 717214518Srpaulo} 718214518Srpaulo 719214518Srpaulostatic int 720214518Srpauloenter_rfmon_mode_mac80211(pcap_t *handle, int sock_fd, const char *device) 721214518Srpaulo{ 722214518Srpaulo int ret; 723214518Srpaulo char phydev_path[PATH_MAX+1]; 724214518Srpaulo struct nl80211_state nlstate; 725214518Srpaulo struct ifreq ifr; 726214518Srpaulo u_int n; 727214518Srpaulo 728214518Srpaulo /* 729214518Srpaulo * Is this a mac80211 device? 730214518Srpaulo */ 731214518Srpaulo ret = get_mac80211_phydev(handle, device, phydev_path, PATH_MAX); 732214518Srpaulo if (ret < 0) 733214518Srpaulo return ret; /* error */ 734214518Srpaulo if (ret == 0) 735214518Srpaulo return 0; /* no error, but not mac80211 device */ 736214518Srpaulo 737214518Srpaulo /* 738214518Srpaulo * XXX - is this already a monN device? 739214518Srpaulo * If so, we're done. 740214518Srpaulo * Is that determined by old Wireless Extensions ioctls? 741214518Srpaulo */ 742214518Srpaulo 743214518Srpaulo /* 744214518Srpaulo * OK, it's apparently a mac80211 device. 745214518Srpaulo * Try to find an unused monN device for it. 746214518Srpaulo */ 747214518Srpaulo ret = nl80211_init(handle, &nlstate, device); 748214518Srpaulo if (ret != 0) 749214518Srpaulo return ret; 750214518Srpaulo for (n = 0; n < UINT_MAX; n++) { 751214518Srpaulo /* 752214518Srpaulo * Try mon{n}. 753214518Srpaulo */ 754214518Srpaulo char mondevice[3+10+1]; /* mon{UINT_MAX}\0 */ 755214518Srpaulo 756214518Srpaulo snprintf(mondevice, sizeof mondevice, "mon%u", n); 757214518Srpaulo ret = add_mon_if(handle, sock_fd, &nlstate, device, mondevice); 758214518Srpaulo if (ret == 1) { 759214518Srpaulo handle->md.mondevice = strdup(mondevice); 760214518Srpaulo goto added; 761214518Srpaulo } 762214518Srpaulo if (ret < 0) { 763214518Srpaulo /* 764214518Srpaulo * Hard failure. Just return ret; handle->errbuf 765214518Srpaulo * has already been set. 766214518Srpaulo */ 767214518Srpaulo nl80211_cleanup(&nlstate); 768214518Srpaulo return ret; 769214518Srpaulo } 770214518Srpaulo } 771214518Srpaulo 772214518Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 773214518Srpaulo "%s: No free monN interfaces", device); 774214518Srpaulo nl80211_cleanup(&nlstate); 775214518Srpaulo return PCAP_ERROR; 776214518Srpaulo 777214518Srpauloadded: 778214518Srpaulo 779214518Srpaulo#if 0 780214518Srpaulo /* 781214518Srpaulo * Sleep for .1 seconds. 782214518Srpaulo */ 783214518Srpaulo delay.tv_sec = 0; 784214518Srpaulo delay.tv_nsec = 500000000; 785214518Srpaulo nanosleep(&delay, NULL); 786214518Srpaulo#endif 787214518Srpaulo 788214518Srpaulo /* 789214518Srpaulo * Now configure the monitor interface up. 790214518Srpaulo */ 791214518Srpaulo memset(&ifr, 0, sizeof(ifr)); 792214518Srpaulo strncpy(ifr.ifr_name, handle->md.mondevice, sizeof(ifr.ifr_name)); 793214518Srpaulo if (ioctl(sock_fd, SIOCGIFFLAGS, &ifr) == -1) { 794214518Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 795214518Srpaulo "%s: Can't get flags for %s: %s", device, 796214518Srpaulo handle->md.mondevice, strerror(errno)); 797214518Srpaulo del_mon_if(handle, sock_fd, &nlstate, device, 798214518Srpaulo handle->md.mondevice); 799214518Srpaulo nl80211_cleanup(&nlstate); 800214518Srpaulo return PCAP_ERROR; 801214518Srpaulo } 802214518Srpaulo ifr.ifr_flags |= IFF_UP|IFF_RUNNING; 803214518Srpaulo if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) { 804214518Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 805214518Srpaulo "%s: Can't set flags for %s: %s", device, 806214518Srpaulo handle->md.mondevice, strerror(errno)); 807214518Srpaulo del_mon_if(handle, sock_fd, &nlstate, device, 808214518Srpaulo handle->md.mondevice); 809214518Srpaulo nl80211_cleanup(&nlstate); 810214518Srpaulo return PCAP_ERROR; 811214518Srpaulo } 812214518Srpaulo 813214518Srpaulo /* 814214518Srpaulo * Success. Clean up the libnl state. 815214518Srpaulo */ 816214518Srpaulo nl80211_cleanup(&nlstate); 817214518Srpaulo 818214518Srpaulo /* 819214518Srpaulo * Note that we have to delete the monitor device when we close 820214518Srpaulo * the handle. 821214518Srpaulo */ 822214518Srpaulo handle->md.must_do_on_close |= MUST_DELETE_MONIF; 823214518Srpaulo 824214518Srpaulo /* 825214518Srpaulo * Add this to the list of pcaps to close when we exit. 826214518Srpaulo */ 827214518Srpaulo pcap_add_to_pcaps_to_close(handle); 828214518Srpaulo 829214518Srpaulo return 1; 830214518Srpaulo} 831214518Srpaulo#endif /* HAVE_LIBNL */ 832214518Srpaulo 833214518Srpaulostatic int 834214518Srpaulopcap_can_set_rfmon_linux(pcap_t *handle) 835214518Srpaulo{ 836214518Srpaulo#ifdef HAVE_LIBNL 837214518Srpaulo char phydev_path[PATH_MAX+1]; 838214518Srpaulo int ret; 839214518Srpaulo#endif 840190225Srpaulo#ifdef IW_MODE_MONITOR 841190225Srpaulo int sock_fd; 842190225Srpaulo struct iwreq ireq; 843190225Srpaulo#endif 844190225Srpaulo 845214518Srpaulo if (strcmp(handle->opt.source, "any") == 0) { 846190225Srpaulo /* 847214518Srpaulo * Monitor mode makes no sense on the "any" device. 848190225Srpaulo */ 849190225Srpaulo return 0; 85075107Sfenner } 85175107Sfenner 852214518Srpaulo#ifdef HAVE_LIBNL 853214518Srpaulo /* 854214518Srpaulo * Bleah. There doesn't seem to be a way to ask a mac80211 855214518Srpaulo * device, through libnl, whether it supports monitor mode; 856214518Srpaulo * we'll just check whether the device appears to be a 857214518Srpaulo * mac80211 device and, if so, assume the device supports 858214518Srpaulo * monitor mode. 859214518Srpaulo * 860214518Srpaulo * wmaster devices don't appear to support the Wireless 861214518Srpaulo * Extensions, but we can create a mon device for a 862214518Srpaulo * wmaster device, so we don't bother checking whether 863214518Srpaulo * a mac80211 device supports the Wireless Extensions. 864214518Srpaulo */ 865214518Srpaulo ret = get_mac80211_phydev(handle, handle->opt.source, phydev_path, 866214518Srpaulo PATH_MAX); 867214518Srpaulo if (ret < 0) 868214518Srpaulo return ret; /* error */ 869214518Srpaulo if (ret == 1) 870214518Srpaulo return 1; /* mac80211 device */ 871214518Srpaulo#endif 872214518Srpaulo 873190225Srpaulo#ifdef IW_MODE_MONITOR 874190225Srpaulo /* 875190225Srpaulo * Bleah. There doesn't appear to be an ioctl to use to ask 876190225Srpaulo * whether a device supports monitor mode; we'll just do 877190225Srpaulo * SIOCGIWMODE and, if it succeeds, assume the device supports 878190225Srpaulo * monitor mode. 879190225Srpaulo * 880190225Srpaulo * Open a socket on which to attempt to get the mode. 881190225Srpaulo * (We assume that if we have Wireless Extensions support 882190225Srpaulo * we also have PF_PACKET support.) 883190225Srpaulo */ 884190225Srpaulo sock_fd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL)); 885190225Srpaulo if (sock_fd == -1) { 886214518Srpaulo (void)snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 887190225Srpaulo "socket: %s", pcap_strerror(errno)); 888190225Srpaulo return PCAP_ERROR; 889190225Srpaulo } 89075107Sfenner 891190225Srpaulo /* 892190225Srpaulo * Attempt to get the current mode. 893190225Srpaulo */ 894214518Srpaulo strncpy(ireq.ifr_ifrn.ifrn_name, handle->opt.source, 895190225Srpaulo sizeof ireq.ifr_ifrn.ifrn_name); 896190225Srpaulo ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0; 897190225Srpaulo if (ioctl(sock_fd, SIOCGIWMODE, &ireq) != -1) { 898190225Srpaulo /* 899190225Srpaulo * Well, we got the mode; assume we can set it. 900190225Srpaulo */ 901190225Srpaulo close(sock_fd); 902190225Srpaulo return 1; 903190225Srpaulo } 904190225Srpaulo if (errno == ENODEV) { 905190225Srpaulo /* The device doesn't even exist. */ 906214518Srpaulo (void)snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 907214518Srpaulo "SIOCGIWMODE failed: %s", pcap_strerror(errno)); 908190225Srpaulo close(sock_fd); 909190225Srpaulo return PCAP_ERROR_NO_SUCH_DEVICE; 910190225Srpaulo } 911190225Srpaulo close(sock_fd); 912190225Srpaulo#endif 913190225Srpaulo return 0; 914190225Srpaulo} 91575107Sfenner 916190225Srpaulo/* 917214518Srpaulo * Grabs the number of dropped packets by the interface from /proc/net/dev. 918214518Srpaulo * 919214518Srpaulo * XXX - what about /sys/class/net/{interface name}/rx_*? There are 920214518Srpaulo * individual devices giving, in ASCII, various rx_ and tx_ statistics. 921214518Srpaulo * 922214518Srpaulo * Or can we get them in binary form from netlink? 923214518Srpaulo */ 924214518Srpaulostatic long int 925214518Srpaulolinux_if_drops(const char * if_name) 926214518Srpaulo{ 927214518Srpaulo char buffer[512]; 928214518Srpaulo char * bufptr; 929214518Srpaulo FILE * file; 930214518Srpaulo int field_to_convert = 3, if_name_sz = strlen(if_name); 931214518Srpaulo long int dropped_pkts = 0; 932214518Srpaulo 933214518Srpaulo file = fopen("/proc/net/dev", "r"); 934214518Srpaulo if (!file) 935214518Srpaulo return 0; 936214518Srpaulo 937214518Srpaulo while (!dropped_pkts && fgets( buffer, sizeof(buffer), file )) 938214518Srpaulo { 939214518Srpaulo /* search for 'bytes' -- if its in there, then 940214518Srpaulo that means we need to grab the fourth field. otherwise 941214518Srpaulo grab the third field. */ 942214518Srpaulo if (field_to_convert != 4 && strstr(buffer, "bytes")) 943214518Srpaulo { 944214518Srpaulo field_to_convert = 4; 945214518Srpaulo continue; 946214518Srpaulo } 947214518Srpaulo 948214518Srpaulo /* find iface and make sure it actually matches -- space before the name and : after it */ 949214518Srpaulo if ((bufptr = strstr(buffer, if_name)) && 950214518Srpaulo (bufptr == buffer || *(bufptr-1) == ' ') && 951214518Srpaulo *(bufptr + if_name_sz) == ':') 952214518Srpaulo { 953214518Srpaulo bufptr = bufptr + if_name_sz + 1; 954214518Srpaulo 955214518Srpaulo /* grab the nth field from it */ 956214518Srpaulo while( --field_to_convert && *bufptr != '\0') 957214518Srpaulo { 958214518Srpaulo while (*bufptr != '\0' && *(bufptr++) == ' '); 959214518Srpaulo while (*bufptr != '\0' && *(bufptr++) != ' '); 960214518Srpaulo } 961214518Srpaulo 962214518Srpaulo /* get rid of any final spaces */ 963214518Srpaulo while (*bufptr != '\0' && *bufptr == ' ') bufptr++; 964214518Srpaulo 965214518Srpaulo if (*bufptr != '\0') 966214518Srpaulo dropped_pkts = strtol(bufptr, NULL, 10); 967214518Srpaulo 968214518Srpaulo break; 969214518Srpaulo } 970214518Srpaulo } 971214518Srpaulo 972214518Srpaulo fclose(file); 973214518Srpaulo return dropped_pkts; 974214518Srpaulo} 975214518Srpaulo 976214518Srpaulo 977214518Srpaulo/* 978190225Srpaulo * With older kernels promiscuous mode is kind of interesting because we 979190225Srpaulo * have to reset the interface before exiting. The problem can't really 980190225Srpaulo * be solved without some daemon taking care of managing usage counts. 981190225Srpaulo * If we put the interface into promiscuous mode, we set a flag indicating 982190225Srpaulo * that we must take it out of that mode when the interface is closed, 983190225Srpaulo * and, when closing the interface, if that flag is set we take it out 984190225Srpaulo * of promiscuous mode. 985190225Srpaulo * 986190225Srpaulo * Even with newer kernels, we have the same issue with rfmon mode. 987190225Srpaulo */ 988190225Srpaulo 989190225Srpaulostatic void pcap_cleanup_linux( pcap_t *handle ) 990190225Srpaulo{ 991190225Srpaulo struct ifreq ifr; 992214518Srpaulo#ifdef HAVE_LIBNL 993214518Srpaulo struct nl80211_state nlstate; 994214518Srpaulo int ret; 995214518Srpaulo#endif /* HAVE_LIBNL */ 996190225Srpaulo#ifdef IW_MODE_MONITOR 997190225Srpaulo struct iwreq ireq; 998214518Srpaulo#endif /* IW_MODE_MONITOR */ 999190225Srpaulo 1000214518Srpaulo if (handle->md.must_do_on_close != 0) { 1001190225Srpaulo /* 1002190225Srpaulo * There's something we have to do when closing this 1003190225Srpaulo * pcap_t. 1004190225Srpaulo */ 1005214518Srpaulo if (handle->md.must_do_on_close & MUST_CLEAR_PROMISC) { 1006190225Srpaulo /* 1007190225Srpaulo * We put the interface into promiscuous mode; 1008190225Srpaulo * take it out of promiscuous mode. 1009190225Srpaulo * 1010190225Srpaulo * XXX - if somebody else wants it in promiscuous 1011190225Srpaulo * mode, this code cannot know that, so it'll take 1012190225Srpaulo * it out of promiscuous mode. That's not fixable 1013190225Srpaulo * in 2.0[.x] kernels. 1014190225Srpaulo */ 1015190225Srpaulo memset(&ifr, 0, sizeof(ifr)); 1016190225Srpaulo strncpy(ifr.ifr_name, handle->md.device, 1017190225Srpaulo sizeof(ifr.ifr_name)); 1018190225Srpaulo if (ioctl(handle->fd, SIOCGIFFLAGS, &ifr) == -1) { 1019190225Srpaulo fprintf(stderr, 1020190225Srpaulo "Can't restore interface flags (SIOCGIFFLAGS failed: %s).\n" 1021190225Srpaulo "Please adjust manually.\n" 1022190225Srpaulo "Hint: This can't happen with Linux >= 2.2.0.\n", 1023190225Srpaulo strerror(errno)); 1024190225Srpaulo } else { 1025190225Srpaulo if (ifr.ifr_flags & IFF_PROMISC) { 1026190225Srpaulo /* 1027190225Srpaulo * Promiscuous mode is currently on; 1028190225Srpaulo * turn it off. 1029190225Srpaulo */ 1030190225Srpaulo ifr.ifr_flags &= ~IFF_PROMISC; 1031190225Srpaulo if (ioctl(handle->fd, SIOCSIFFLAGS, 1032190225Srpaulo &ifr) == -1) { 1033190225Srpaulo fprintf(stderr, 1034190225Srpaulo "Can't restore interface flags (SIOCSIFFLAGS failed: %s).\n" 1035190225Srpaulo "Please adjust manually.\n" 1036190225Srpaulo "Hint: This can't happen with Linux >= 2.2.0.\n", 1037190225Srpaulo strerror(errno)); 1038190225Srpaulo } 1039190225Srpaulo } 1040190225Srpaulo } 1041190225Srpaulo } 1042190225Srpaulo 1043214518Srpaulo#ifdef HAVE_LIBNL 1044214518Srpaulo if (handle->md.must_do_on_close & MUST_DELETE_MONIF) { 1045214518Srpaulo ret = nl80211_init(handle, &nlstate, handle->md.device); 1046214518Srpaulo if (ret >= 0) { 1047214518Srpaulo ret = del_mon_if(handle, handle->fd, &nlstate, 1048214518Srpaulo handle->md.device, handle->md.mondevice); 1049214518Srpaulo nl80211_cleanup(&nlstate); 1050214518Srpaulo } 1051214518Srpaulo if (ret < 0) { 1052214518Srpaulo fprintf(stderr, 1053214518Srpaulo "Can't delete monitor interface %s (%s).\n" 1054214518Srpaulo "Please delete manually.\n", 1055214518Srpaulo handle->md.mondevice, handle->errbuf); 1056214518Srpaulo } 1057214518Srpaulo } 1058214518Srpaulo#endif /* HAVE_LIBNL */ 1059214518Srpaulo 1060190225Srpaulo#ifdef IW_MODE_MONITOR 1061214518Srpaulo if (handle->md.must_do_on_close & MUST_CLEAR_RFMON) { 1062190225Srpaulo /* 1063190225Srpaulo * We put the interface into rfmon mode; 1064190225Srpaulo * take it out of rfmon mode. 1065190225Srpaulo * 1066190225Srpaulo * XXX - if somebody else wants it in rfmon 1067190225Srpaulo * mode, this code cannot know that, so it'll take 1068190225Srpaulo * it out of rfmon mode. 1069190225Srpaulo */ 1070190225Srpaulo strncpy(ireq.ifr_ifrn.ifrn_name, handle->md.device, 1071190225Srpaulo sizeof ireq.ifr_ifrn.ifrn_name); 1072190225Srpaulo ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] 1073190225Srpaulo = 0; 1074190225Srpaulo ireq.u.mode = handle->md.oldmode; 1075190225Srpaulo if (ioctl(handle->fd, SIOCSIWMODE, &ireq) == -1) { 1076190225Srpaulo /* 1077190225Srpaulo * Scientist, you've failed. 1078190225Srpaulo */ 1079190225Srpaulo fprintf(stderr, 1080190225Srpaulo "Can't restore interface wireless mode (SIOCSIWMODE failed: %s).\n" 1081190225Srpaulo "Please adjust manually.\n", 1082190225Srpaulo strerror(errno)); 1083190225Srpaulo } 1084190225Srpaulo } 1085214518Srpaulo#endif /* IW_MODE_MONITOR */ 1086190225Srpaulo 1087190225Srpaulo /* 1088190225Srpaulo * Take this pcap out of the list of pcaps for which we 1089190225Srpaulo * have to take the interface out of some mode. 1090190225Srpaulo */ 1091190225Srpaulo pcap_remove_from_pcaps_to_close(handle); 1092190225Srpaulo } 1093190225Srpaulo 1094214518Srpaulo if (handle->md.mondevice != NULL) { 1095214518Srpaulo free(handle->md.mondevice); 1096214518Srpaulo handle->md.mondevice = NULL; 1097214518Srpaulo } 1098190225Srpaulo if (handle->md.device != NULL) { 1099190225Srpaulo free(handle->md.device); 1100190225Srpaulo handle->md.device = NULL; 1101190225Srpaulo } 1102190225Srpaulo pcap_cleanup_live_common(handle); 1103190225Srpaulo} 1104190225Srpaulo 1105190225Srpaulo/* 1106190225Srpaulo * Get a handle for a live capture from the given device. You can 1107190225Srpaulo * pass NULL as device to get all packages (without link level 1108190225Srpaulo * information of course). If you pass 1 as promisc the interface 1109190225Srpaulo * will be set to promiscous mode (XXX: I think this usage should 1110190225Srpaulo * be deprecated and functions be added to select that later allow 1111190225Srpaulo * modification of that values -- Torsten). 1112190225Srpaulo */ 1113190225Srpaulostatic int 1114190225Srpaulopcap_activate_linux(pcap_t *handle) 1115190225Srpaulo{ 1116190225Srpaulo const char *device; 1117190225Srpaulo int status = 0; 1118190225Srpaulo 1119190225Srpaulo device = handle->opt.source; 1120190225Srpaulo 1121190225Srpaulo handle->inject_op = pcap_inject_linux; 1122190225Srpaulo handle->setfilter_op = pcap_setfilter_linux; 1123190225Srpaulo handle->setdirection_op = pcap_setdirection_linux; 1124190225Srpaulo handle->set_datalink_op = NULL; /* can't change data link type */ 1125190225Srpaulo handle->getnonblock_op = pcap_getnonblock_fd; 1126190225Srpaulo handle->setnonblock_op = pcap_setnonblock_fd; 1127190225Srpaulo handle->cleanup_op = pcap_cleanup_linux; 1128190225Srpaulo handle->read_op = pcap_read_linux; 1129190225Srpaulo handle->stats_op = pcap_stats_linux; 1130190225Srpaulo 113175107Sfenner /* 1132214518Srpaulo * The "any" device is a special device which causes us not 1133214518Srpaulo * to bind to a particular device and thus to look at all 1134214518Srpaulo * devices. 113575107Sfenner */ 1136214518Srpaulo if (strcmp(device, "any") == 0) { 1137190225Srpaulo if (handle->opt.promisc) { 1138190225Srpaulo handle->opt.promisc = 0; 113998530Sfenner /* Just a warning. */ 1140190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 114198530Sfenner "Promiscuous mode not supported on the \"any\" device"); 1142190225Srpaulo status = PCAP_WARNING_PROMISC_NOTSUP; 114398530Sfenner } 1144214518Srpaulo } 1145127664Sbms 1146214518Srpaulo handle->md.device = strdup(device); 114775107Sfenner if (handle->md.device == NULL) { 1148190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "strdup: %s", 114975107Sfenner pcap_strerror(errno) ); 1150190225Srpaulo return PCAP_ERROR; 115175107Sfenner } 1152214518Srpaulo 1153214518Srpaulo /* 1154214518Srpaulo * If we're in promiscuous mode, then we probably want 1155214518Srpaulo * to see when the interface drops packets too, so get an 1156214518Srpaulo * initial count from /proc/net/dev 1157214518Srpaulo */ 1158214518Srpaulo if (handle->opt.promisc) 1159214518Srpaulo handle->md.proc_dropped = linux_if_drops(handle->md.device); 116075107Sfenner 1161127664Sbms /* 1162127664Sbms * Current Linux kernels use the protocol family PF_PACKET to 1163127664Sbms * allow direct access to all packets on the network while 1164127664Sbms * older kernels had a special socket type SOCK_PACKET to 116575107Sfenner * implement this feature. 116675107Sfenner * While this old implementation is kind of obsolete we need 1167127664Sbms * to be compatible with older kernels for a while so we are 116875107Sfenner * trying both methods with the newer method preferred. 116975107Sfenner */ 117075107Sfenner 1171190225Srpaulo if ((status = activate_new(handle)) == 1) { 1172190225Srpaulo /* 1173214518Srpaulo * Success. 1174190225Srpaulo * Try to use memory-mapped access. 1175190225Srpaulo */ 1176214518Srpaulo switch (activate_mmap(handle)) { 1177214518Srpaulo 1178214518Srpaulo case 1: 1179214518Srpaulo /* we succeeded; nothing more to do */ 1180214518Srpaulo return 0; 1181214518Srpaulo 1182214518Srpaulo case 0: 1183214518Srpaulo /* 1184214518Srpaulo * Kernel doesn't support it - just continue 1185214518Srpaulo * with non-memory-mapped access. 1186214518Srpaulo */ 1187214518Srpaulo status = 0; 1188214518Srpaulo break; 1189214518Srpaulo 1190214518Srpaulo case -1: 1191214518Srpaulo /* 1192214518Srpaulo * We failed to set up to use it, or kernel 1193214518Srpaulo * supports it, but we failed to enable it; 1194214518Srpaulo * return an error. handle->errbuf contains 1195214518Srpaulo * an error message. 1196214518Srpaulo */ 1197214518Srpaulo status = PCAP_ERROR; 1198214518Srpaulo goto fail; 1199214518Srpaulo } 1200190225Srpaulo } 1201190225Srpaulo else if (status == 0) { 1202127664Sbms /* Non-fatal error; try old way */ 1203214518Srpaulo if ((status = activate_old(handle)) != 1) { 1204214518Srpaulo /* 1205214518Srpaulo * Both methods to open the packet socket failed. 1206214518Srpaulo * Tidy up and report our failure (handle->errbuf 1207214518Srpaulo * is expected to be set by the functions above). 1208214518Srpaulo */ 1209214518Srpaulo goto fail; 1210214518Srpaulo } 1211214518Srpaulo } else { 1212127664Sbms /* 1213214518Srpaulo * Fatal error with the new way; just fail. 1214214518Srpaulo * status has the error return; if it's PCAP_ERROR, 1215214518Srpaulo * handle->errbuf has been set appropriately. 121675107Sfenner */ 1217190225Srpaulo goto fail; 121875107Sfenner } 121975107Sfenner 1220214518Srpaulo /* 1221214518Srpaulo * We set up the socket, but not with memory-mapped access. 1222214518Srpaulo */ 1223190225Srpaulo if (handle->opt.buffer_size != 0) { 122498530Sfenner /* 1225190225Srpaulo * Set the socket buffer size to the specified value. 122698530Sfenner */ 1227190225Srpaulo if (setsockopt(handle->fd, SOL_SOCKET, SO_RCVBUF, 1228190225Srpaulo &handle->opt.buffer_size, 1229190225Srpaulo sizeof(handle->opt.buffer_size)) == -1) { 1230190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 1231190225Srpaulo "SO_RCVBUF: %s", pcap_strerror(errno)); 1232190225Srpaulo status = PCAP_ERROR; 1233190225Srpaulo goto fail; 123498530Sfenner } 123598530Sfenner } 123698530Sfenner 123798530Sfenner /* Allocate the buffer */ 123898530Sfenner 123998530Sfenner handle->buffer = malloc(handle->bufsize + handle->offset); 124098530Sfenner if (!handle->buffer) { 1241190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 124298530Sfenner "malloc: %s", pcap_strerror(errno)); 1243190225Srpaulo status = PCAP_ERROR; 1244190225Srpaulo goto fail; 124598530Sfenner } 124698530Sfenner 1247127664Sbms /* 1248127664Sbms * "handle->fd" is a socket, so "select()" and "poll()" 1249127664Sbms * should work on it. 1250127664Sbms */ 1251127664Sbms handle->selectable_fd = handle->fd; 1252127664Sbms 1253190225Srpaulo return status; 1254127664Sbms 1255190225Srpaulofail: 1256190225Srpaulo pcap_cleanup_linux(handle); 1257190225Srpaulo return status; 125826175Sfenner} 125926175Sfenner 126075107Sfenner/* 126175107Sfenner * Read at most max_packets from the capture stream and call the callback 126275107Sfenner * for each of them. Returns the number of packets handled or -1 if an 1263127664Sbms * error occured. 126475107Sfenner */ 1265127664Sbmsstatic int 1266127664Sbmspcap_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user) 126726175Sfenner{ 126875107Sfenner /* 126975107Sfenner * Currently, on Linux only one packet is delivered per read, 127075107Sfenner * so we don't loop. 127175107Sfenner */ 127275107Sfenner return pcap_read_packet(handle, callback, user); 127375107Sfenner} 127426175Sfenner 127575107Sfenner/* 1276127664Sbms * Read a packet from the socket calling the handler provided by 127775107Sfenner * the user. Returns the number of packets received or -1 if an 127875107Sfenner * error occured. 127975107Sfenner */ 128075107Sfennerstatic int 128175107Sfennerpcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata) 128275107Sfenner{ 128398530Sfenner u_char *bp; 128475107Sfenner int offset; 128575107Sfenner#ifdef HAVE_PF_PACKET_SOCKETS 128675107Sfenner struct sockaddr_ll from; 128775107Sfenner struct sll_header *hdrp; 128875107Sfenner#else 128975107Sfenner struct sockaddr from; 129075107Sfenner#endif 1291190225Srpaulo#if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) 1292190225Srpaulo struct iovec iov; 1293190225Srpaulo struct msghdr msg; 1294190225Srpaulo struct cmsghdr *cmsg; 1295190225Srpaulo union { 1296190225Srpaulo struct cmsghdr cmsg; 1297190225Srpaulo char buf[CMSG_SPACE(sizeof(struct tpacket_auxdata))]; 1298190225Srpaulo } cmsg_buf; 1299190225Srpaulo#else /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */ 130075107Sfenner socklen_t fromlen; 1301190225Srpaulo#endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */ 130275107Sfenner int packet_len, caplen; 130375107Sfenner struct pcap_pkthdr pcap_header; 130426175Sfenner 130575107Sfenner#ifdef HAVE_PF_PACKET_SOCKETS 130675107Sfenner /* 130775107Sfenner * If this is a cooked device, leave extra room for a 130875107Sfenner * fake packet header. 130975107Sfenner */ 131075107Sfenner if (handle->md.cooked) 131175107Sfenner offset = SLL_HDR_LEN; 131275107Sfenner else 131375107Sfenner offset = 0; 131475107Sfenner#else 131575107Sfenner /* 131675107Sfenner * This system doesn't have PF_PACKET sockets, so it doesn't 131775107Sfenner * support cooked devices. 131875107Sfenner */ 131975107Sfenner offset = 0; 132075107Sfenner#endif 132175107Sfenner 1322190225Srpaulo /* 1323190225Srpaulo * Receive a single packet from the kernel. 1324190225Srpaulo * We ignore EINTR, as that might just be due to a signal 1325190225Srpaulo * being delivered - if the signal should interrupt the 1326190225Srpaulo * loop, the signal handler should call pcap_breakloop() 1327190225Srpaulo * to set handle->break_loop (we ignore it on other 1328190225Srpaulo * platforms as well). 1329190225Srpaulo * We also ignore ENETDOWN, so that we can continue to 1330190225Srpaulo * capture traffic if the interface goes down and comes 1331190225Srpaulo * back up again; comments in the kernel indicate that 1332190225Srpaulo * we'll just block waiting for packets if we try to 1333190225Srpaulo * receive from a socket that delivered ENETDOWN, and, 1334190225Srpaulo * if we're using a memory-mapped buffer, we won't even 1335190225Srpaulo * get notified of "network down" events. 1336190225Srpaulo */ 1337190225Srpaulo bp = handle->buffer + handle->offset; 133875107Sfenner 1339190225Srpaulo#if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) 1340190225Srpaulo msg.msg_name = &from; 1341190225Srpaulo msg.msg_namelen = sizeof(from); 1342190225Srpaulo msg.msg_iov = &iov; 1343190225Srpaulo msg.msg_iovlen = 1; 1344190225Srpaulo msg.msg_control = &cmsg_buf; 1345190225Srpaulo msg.msg_controllen = sizeof(cmsg_buf); 1346190225Srpaulo msg.msg_flags = 0; 1347190225Srpaulo 1348190225Srpaulo iov.iov_len = handle->bufsize - offset; 1349190225Srpaulo iov.iov_base = bp + offset; 1350190225Srpaulo#endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */ 1351190225Srpaulo 135226175Sfenner do { 1353127664Sbms /* 1354127664Sbms * Has "pcap_breakloop()" been called? 1355127664Sbms */ 1356127664Sbms if (handle->break_loop) { 1357127664Sbms /* 1358214518Srpaulo * Yes - clear the flag that indicates that it has, 1359214518Srpaulo * and return PCAP_ERROR_BREAK as an indication that 1360214518Srpaulo * we were told to break out of the loop. 1361127664Sbms */ 1362127664Sbms handle->break_loop = 0; 1363214518Srpaulo return PCAP_ERROR_BREAK; 1364127664Sbms } 1365190225Srpaulo 1366190225Srpaulo#if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) 1367190225Srpaulo packet_len = recvmsg(handle->fd, &msg, MSG_TRUNC); 1368190225Srpaulo#else /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */ 136926175Sfenner fromlen = sizeof(from); 1370127664Sbms packet_len = recvfrom( 137198530Sfenner handle->fd, bp + offset, 1372127664Sbms handle->bufsize - offset, MSG_TRUNC, 137375107Sfenner (struct sockaddr *) &from, &fromlen); 1374190225Srpaulo#endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */ 1375214518Srpaulo } while (packet_len == -1 && errno == EINTR); 137626175Sfenner 137775107Sfenner /* Check if an error occured */ 137826175Sfenner 137975107Sfenner if (packet_len == -1) { 1380214518Srpaulo switch (errno) { 1381214518Srpaulo 1382214518Srpaulo case EAGAIN: 138375107Sfenner return 0; /* no packet there */ 1384214518Srpaulo 1385214518Srpaulo case ENETDOWN: 1386214518Srpaulo /* 1387214518Srpaulo * The device on which we're capturing went away. 1388214518Srpaulo * 1389214518Srpaulo * XXX - we should really return 1390214518Srpaulo * PCAP_ERROR_IFACE_NOT_UP, but pcap_dispatch() 1391214518Srpaulo * etc. aren't defined to return that. 1392214518Srpaulo */ 1393190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 1394214518Srpaulo "The interface went down"); 1395214518Srpaulo return PCAP_ERROR; 1396214518Srpaulo 1397214518Srpaulo default: 1398214518Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 139975107Sfenner "recvfrom: %s", pcap_strerror(errno)); 1400214518Srpaulo return PCAP_ERROR; 140126175Sfenner } 140275107Sfenner } 140326175Sfenner 140475107Sfenner#ifdef HAVE_PF_PACKET_SOCKETS 1405147894Ssam if (!handle->md.sock_packet) { 1406147894Ssam /* 1407172677Smlaier * Unfortunately, there is a window between socket() and 1408172677Smlaier * bind() where the kernel may queue packets from any 1409172677Smlaier * interface. If we're bound to a particular interface, 1410172677Smlaier * discard packets not from that interface. 1411172677Smlaier * 1412172677Smlaier * (If socket filters are supported, we could do the 1413172677Smlaier * same thing we do when changing the filter; however, 1414172677Smlaier * that won't handle packet sockets without socket 1415172677Smlaier * filter support, and it's a bit more complicated. 1416172677Smlaier * It would save some instructions per packet, however.) 1417172677Smlaier */ 1418172677Smlaier if (handle->md.ifindex != -1 && 1419172677Smlaier from.sll_ifindex != handle->md.ifindex) 1420172677Smlaier return 0; 1421172677Smlaier 1422172677Smlaier /* 1423147894Ssam * Do checks based on packet direction. 1424147894Ssam * We can only do this if we're using PF_PACKET; the 1425147894Ssam * address returned for SOCK_PACKET is a "sockaddr_pkt" 1426147894Ssam * which lacks the relevant packet type information. 1427147894Ssam */ 1428147894Ssam if (from.sll_pkttype == PACKET_OUTGOING) { 1429147894Ssam /* 1430147894Ssam * Outgoing packet. 1431147894Ssam * If this is from the loopback device, reject it; 1432147894Ssam * we'll see the packet as an incoming packet as well, 1433147894Ssam * and we don't want to see it twice. 1434147894Ssam */ 1435147894Ssam if (from.sll_ifindex == handle->md.lo_ifindex) 1436147894Ssam return 0; 1437147894Ssam 1438147894Ssam /* 1439147894Ssam * If the user only wants incoming packets, reject it. 1440147894Ssam */ 1441162012Ssam if (handle->direction == PCAP_D_IN) 1442147894Ssam return 0; 1443147894Ssam } else { 1444147894Ssam /* 1445147894Ssam * Incoming packet. 1446147894Ssam * If the user only wants outgoing packets, reject it. 1447147894Ssam */ 1448162012Ssam if (handle->direction == PCAP_D_OUT) 1449147894Ssam return 0; 1450147894Ssam } 1451147894Ssam } 145275107Sfenner#endif 145326175Sfenner 145475107Sfenner#ifdef HAVE_PF_PACKET_SOCKETS 145575107Sfenner /* 145675107Sfenner * If this is a cooked device, fill in the fake packet header. 145775107Sfenner */ 145875107Sfenner if (handle->md.cooked) { 145975107Sfenner /* 146075107Sfenner * Add the length of the fake header to the length 146175107Sfenner * of packet data we read. 146275107Sfenner */ 146375107Sfenner packet_len += SLL_HDR_LEN; 146426175Sfenner 146598530Sfenner hdrp = (struct sll_header *)bp; 1466190225Srpaulo hdrp->sll_pkttype = map_packet_type_to_sll_type(from.sll_pkttype); 1467190225Srpaulo hdrp->sll_hatype = htons(from.sll_hatype); 1468190225Srpaulo hdrp->sll_halen = htons(from.sll_halen); 1469190225Srpaulo memcpy(hdrp->sll_addr, from.sll_addr, 1470190225Srpaulo (from.sll_halen > SLL_ADDRLEN) ? 1471190225Srpaulo SLL_ADDRLEN : 1472190225Srpaulo from.sll_halen); 1473190225Srpaulo hdrp->sll_protocol = from.sll_protocol; 1474190225Srpaulo } 147526175Sfenner 1476190225Srpaulo#if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) 1477190225Srpaulo for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) { 1478190225Srpaulo struct tpacket_auxdata *aux; 1479190225Srpaulo unsigned int len; 1480190225Srpaulo struct vlan_tag *tag; 148126175Sfenner 1482190225Srpaulo if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct tpacket_auxdata)) || 1483190225Srpaulo cmsg->cmsg_level != SOL_PACKET || 1484190225Srpaulo cmsg->cmsg_type != PACKET_AUXDATA) 1485190225Srpaulo continue; 148626175Sfenner 1487190225Srpaulo aux = (struct tpacket_auxdata *)CMSG_DATA(cmsg); 1488190225Srpaulo if (aux->tp_vlan_tci == 0) 1489190225Srpaulo continue; 149075107Sfenner 1491190225Srpaulo len = packet_len > iov.iov_len ? iov.iov_len : packet_len; 1492190225Srpaulo if (len < 2 * ETH_ALEN) 149375107Sfenner break; 149475107Sfenner 1495190225Srpaulo bp -= VLAN_TAG_LEN; 1496190225Srpaulo memmove(bp, bp + VLAN_TAG_LEN, 2 * ETH_ALEN); 149775107Sfenner 1498190225Srpaulo tag = (struct vlan_tag *)(bp + 2 * ETH_ALEN); 1499190225Srpaulo tag->vlan_tpid = htons(ETH_P_8021Q); 1500190225Srpaulo tag->vlan_tci = htons(aux->tp_vlan_tci); 150175107Sfenner 1502190225Srpaulo packet_len += VLAN_TAG_LEN; 150326175Sfenner } 1504190225Srpaulo#endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */ 1505190225Srpaulo#endif /* HAVE_PF_PACKET_SOCKETS */ 150675107Sfenner 150775107Sfenner /* 1508127664Sbms * XXX: According to the kernel source we should get the real 1509127664Sbms * packet len if calling recvfrom with MSG_TRUNC set. It does 151075107Sfenner * not seem to work here :(, but it is supported by this code 1511127664Sbms * anyway. 151275107Sfenner * To be honest the code RELIES on that feature so this is really 151375107Sfenner * broken with 2.2.x kernels. 151475107Sfenner * I spend a day to figure out what's going on and I found out 1515127664Sbms * that the following is happening: 151675107Sfenner * 1517127664Sbms * The packet comes from a random interface and the packet_rcv 151875107Sfenner * hook is called with a clone of the packet. That code inserts 151975107Sfenner * the packet into the receive queue of the packet socket. 152075107Sfenner * If a filter is attached to that socket that filter is run 152175107Sfenner * first - and there lies the problem. The default filter always 152275107Sfenner * cuts the packet at the snaplen: 152375107Sfenner * 152475107Sfenner * # tcpdump -d 152575107Sfenner * (000) ret #68 152675107Sfenner * 1527127664Sbms * So the packet filter cuts down the packet. The recvfrom call 152875107Sfenner * says "hey, it's only 68 bytes, it fits into the buffer" with 1529127664Sbms * the result that we don't get the real packet length. This 1530127664Sbms * is valid at least until kernel 2.2.17pre6. 153175107Sfenner * 153275107Sfenner * We currently handle this by making a copy of the filter 153375107Sfenner * program, fixing all "ret" instructions with non-zero 153475107Sfenner * operands to have an operand of 65535 so that the filter 153575107Sfenner * doesn't truncate the packet, and supplying that modified 153675107Sfenner * filter to the kernel. 153775107Sfenner */ 153875107Sfenner 153975107Sfenner caplen = packet_len; 154075107Sfenner if (caplen > handle->snapshot) 154175107Sfenner caplen = handle->snapshot; 154275107Sfenner 154375107Sfenner /* Run the packet filter if not using kernel filter */ 154475107Sfenner if (!handle->md.use_bpf && handle->fcode.bf_insns) { 154598530Sfenner if (bpf_filter(handle->fcode.bf_insns, bp, 154675107Sfenner packet_len, caplen) == 0) 154775107Sfenner { 154875107Sfenner /* rejected by filter */ 154975107Sfenner return 0; 155075107Sfenner } 155175107Sfenner } 155275107Sfenner 155375107Sfenner /* Fill in our own header data */ 155475107Sfenner 155575107Sfenner if (ioctl(handle->fd, SIOCGSTAMP, &pcap_header.ts) == -1) { 1556190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 1557172677Smlaier "SIOCGSTAMP: %s", pcap_strerror(errno)); 1558214518Srpaulo return PCAP_ERROR; 155975107Sfenner } 156075107Sfenner pcap_header.caplen = caplen; 156175107Sfenner pcap_header.len = packet_len; 156275107Sfenner 156398530Sfenner /* 156498530Sfenner * Count the packet. 156598530Sfenner * 156698530Sfenner * Arguably, we should count them before we check the filter, 156798530Sfenner * as on many other platforms "ps_recv" counts packets 156898530Sfenner * handed to the filter rather than packets that passed 156998530Sfenner * the filter, but if filtering is done in the kernel, we 157098530Sfenner * can't get a count of packets that passed the filter, 157198530Sfenner * and that would mean the meaning of "ps_recv" wouldn't 157298530Sfenner * be the same on all Linux systems. 157398530Sfenner * 157498530Sfenner * XXX - it's not the same on all systems in any case; 157598530Sfenner * ideally, we should have a "get the statistics" call 157698530Sfenner * that supplies more counts and indicates which of them 157798530Sfenner * it supplies, so that we supply a count of packets 157898530Sfenner * handed to the filter only on platforms where that 157998530Sfenner * information is available. 158098530Sfenner * 158198530Sfenner * We count them here even if we can get the packet count 158298530Sfenner * from the kernel, as we can only determine at run time 158398530Sfenner * whether we'll be able to get it from the kernel (if 158498530Sfenner * HAVE_TPACKET_STATS isn't defined, we can't get it from 158598530Sfenner * the kernel, but if it is defined, the library might 158698530Sfenner * have been built with a 2.4 or later kernel, but we 158798530Sfenner * might be running on a 2.2[.x] kernel without Alexey 158898530Sfenner * Kuznetzov's turbopacket patches, and thus the kernel 158998530Sfenner * might not be able to supply those statistics). We 159098530Sfenner * could, I guess, try, when opening the socket, to get 159198530Sfenner * the statistics, and if we can not increment the count 159298530Sfenner * here, but it's not clear that always incrementing 159398530Sfenner * the count is more expensive than always testing a flag 159498530Sfenner * in memory. 1595172677Smlaier * 1596172677Smlaier * We keep the count in "md.packets_read", and use that for 1597172677Smlaier * "ps_recv" if we can't get the statistics from the kernel. 1598172677Smlaier * We do that because, if we *can* get the statistics from 1599172677Smlaier * the kernel, we use "md.stat.ps_recv" and "md.stat.ps_drop" 1600172677Smlaier * as running counts, as reading the statistics from the 1601172677Smlaier * kernel resets the kernel statistics, and if we directly 1602172677Smlaier * increment "md.stat.ps_recv" here, that means it will 1603172677Smlaier * count packets *twice* on systems where we can get kernel 1604172677Smlaier * statistics - once here, and once in pcap_stats_linux(). 160598530Sfenner */ 1606172677Smlaier handle->md.packets_read++; 160775107Sfenner 160898530Sfenner /* Call the user supplied callback function */ 160998530Sfenner callback(userdata, &pcap_header, bp); 161098530Sfenner 161175107Sfenner return 1; 161226175Sfenner} 161326175Sfenner 1614146768Ssamstatic int 1615146768Ssampcap_inject_linux(pcap_t *handle, const void *buf, size_t size) 1616146768Ssam{ 1617146768Ssam int ret; 1618146768Ssam 1619146768Ssam#ifdef HAVE_PF_PACKET_SOCKETS 1620146768Ssam if (!handle->md.sock_packet) { 1621146768Ssam /* PF_PACKET socket */ 1622146768Ssam if (handle->md.ifindex == -1) { 1623146768Ssam /* 1624146768Ssam * We don't support sending on the "any" device. 1625146768Ssam */ 1626146768Ssam strlcpy(handle->errbuf, 1627146768Ssam "Sending packets isn't supported on the \"any\" device", 1628146768Ssam PCAP_ERRBUF_SIZE); 1629146768Ssam return (-1); 1630146768Ssam } 1631146768Ssam 1632146768Ssam if (handle->md.cooked) { 1633146768Ssam /* 1634146768Ssam * We don't support sending on the "any" device. 1635146768Ssam * 1636146768Ssam * XXX - how do you send on a bound cooked-mode 1637146768Ssam * socket? 1638146768Ssam * Is a "sendto()" required there? 1639146768Ssam */ 1640146768Ssam strlcpy(handle->errbuf, 1641146768Ssam "Sending packets isn't supported in cooked mode", 1642146768Ssam PCAP_ERRBUF_SIZE); 1643146768Ssam return (-1); 1644146768Ssam } 1645146768Ssam } 1646146768Ssam#endif 1647146768Ssam 1648146768Ssam ret = send(handle->fd, buf, size, 0); 1649146768Ssam if (ret == -1) { 1650146768Ssam snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "send: %s", 1651146768Ssam pcap_strerror(errno)); 1652146768Ssam return (-1); 1653146768Ssam } 1654146768Ssam return (ret); 1655146768Ssam} 1656146768Ssam 165775107Sfenner/* 165875107Sfenner * Get the statistics for the given packet capture handle. 165998530Sfenner * Reports the number of dropped packets iff the kernel supports 166098530Sfenner * the PACKET_STATISTICS "getsockopt()" argument (2.4 and later 166198530Sfenner * kernels, and 2.2[.x] kernels with Alexey Kuznetzov's turbopacket 166298530Sfenner * patches); otherwise, that information isn't available, and we lie 166398530Sfenner * and report 0 as the count of dropped packets. 166475107Sfenner */ 1665127664Sbmsstatic int 1666127664Sbmspcap_stats_linux(pcap_t *handle, struct pcap_stat *stats) 166726175Sfenner{ 166898530Sfenner#ifdef HAVE_TPACKET_STATS 166998530Sfenner struct tpacket_stats kstats; 167098530Sfenner socklen_t len = sizeof (struct tpacket_stats); 1671127664Sbms#endif 167298530Sfenner 1673214518Srpaulo long if_dropped = 0; 1674214518Srpaulo 1675214518Srpaulo /* 1676214518Srpaulo * To fill in ps_ifdrop, we parse /proc/net/dev for the number 1677214518Srpaulo */ 1678214518Srpaulo if (handle->opt.promisc) 1679214518Srpaulo { 1680214518Srpaulo if_dropped = handle->md.proc_dropped; 1681214518Srpaulo handle->md.proc_dropped = linux_if_drops(handle->md.device); 1682214518Srpaulo handle->md.stat.ps_ifdrop += (handle->md.proc_dropped - if_dropped); 1683214518Srpaulo } 1684214518Srpaulo 1685127664Sbms#ifdef HAVE_TPACKET_STATS 168698530Sfenner /* 168798530Sfenner * Try to get the packet counts from the kernel. 168898530Sfenner */ 168998530Sfenner if (getsockopt(handle->fd, SOL_PACKET, PACKET_STATISTICS, 169098530Sfenner &kstats, &len) > -1) { 169198530Sfenner /* 1692172677Smlaier * On systems where the PACKET_STATISTICS "getsockopt()" 1693172677Smlaier * argument is supported on PF_PACKET sockets: 1694172677Smlaier * 1695172677Smlaier * "ps_recv" counts only packets that *passed* the 1696172677Smlaier * filter, not packets that didn't pass the filter. 1697172677Smlaier * This includes packets later dropped because we 1698172677Smlaier * ran out of buffer space. 1699172677Smlaier * 1700172677Smlaier * "ps_drop" counts packets dropped because we ran 1701172677Smlaier * out of buffer space. It doesn't count packets 1702172677Smlaier * dropped by the interface driver. It counts only 1703172677Smlaier * packets that passed the filter. 1704172677Smlaier * 1705214518Srpaulo * See above for ps_ifdrop. 1706214518Srpaulo * 1707172677Smlaier * Both statistics include packets not yet read from 1708172677Smlaier * the kernel by libpcap, and thus not yet seen by 1709172677Smlaier * the application. 1710172677Smlaier * 171198530Sfenner * In "linux/net/packet/af_packet.c", at least in the 171298530Sfenner * 2.4.9 kernel, "tp_packets" is incremented for every 171398530Sfenner * packet that passes the packet filter *and* is 171498530Sfenner * successfully queued on the socket; "tp_drops" is 171598530Sfenner * incremented for every packet dropped because there's 171698530Sfenner * not enough free space in the socket buffer. 171798530Sfenner * 171898530Sfenner * When the statistics are returned for a PACKET_STATISTICS 171998530Sfenner * "getsockopt()" call, "tp_drops" is added to "tp_packets", 172098530Sfenner * so that "tp_packets" counts all packets handed to 172198530Sfenner * the PF_PACKET socket, including packets dropped because 172298530Sfenner * there wasn't room on the socket buffer - but not 172398530Sfenner * including packets that didn't pass the filter. 172498530Sfenner * 172598530Sfenner * In the BSD BPF, the count of received packets is 172698530Sfenner * incremented for every packet handed to BPF, regardless 172798530Sfenner * of whether it passed the filter. 172898530Sfenner * 172998530Sfenner * We can't make "pcap_stats()" work the same on both 173098530Sfenner * platforms, but the best approximation is to return 173198530Sfenner * "tp_packets" as the count of packets and "tp_drops" 173298530Sfenner * as the count of drops. 1733146768Ssam * 1734146768Ssam * Keep a running total because each call to 1735146768Ssam * getsockopt(handle->fd, SOL_PACKET, PACKET_STATISTICS, .... 1736146768Ssam * resets the counters to zero. 173798530Sfenner */ 1738146768Ssam handle->md.stat.ps_recv += kstats.tp_packets; 1739146768Ssam handle->md.stat.ps_drop += kstats.tp_drops; 1740172677Smlaier *stats = handle->md.stat; 1741172677Smlaier return 0; 174298530Sfenner } 174398530Sfenner else 174498530Sfenner { 174598530Sfenner /* 174698530Sfenner * If the error was EOPNOTSUPP, fall through, so that 174798530Sfenner * if you build the library on a system with 174898530Sfenner * "struct tpacket_stats" and run it on a system 174998530Sfenner * that doesn't, it works as it does if the library 175098530Sfenner * is built on a system without "struct tpacket_stats". 175198530Sfenner */ 175298530Sfenner if (errno != EOPNOTSUPP) { 175398530Sfenner snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 175498530Sfenner "pcap_stats: %s", pcap_strerror(errno)); 175598530Sfenner return -1; 175698530Sfenner } 175798530Sfenner } 175898530Sfenner#endif 175998530Sfenner /* 176098530Sfenner * On systems where the PACKET_STATISTICS "getsockopt()" argument 176198530Sfenner * is not supported on PF_PACKET sockets: 176298530Sfenner * 176398530Sfenner * "ps_recv" counts only packets that *passed* the filter, 176498530Sfenner * not packets that didn't pass the filter. It does not 176598530Sfenner * count packets dropped because we ran out of buffer 176698530Sfenner * space. 176798530Sfenner * 176898530Sfenner * "ps_drop" is not supported. 176998530Sfenner * 1770214518Srpaulo * "ps_ifdrop" is supported. It will return the number 1771214518Srpaulo * of drops the interface reports in /proc/net/dev, 1772214518Srpaulo * if that is available. 1773214518Srpaulo * 177498530Sfenner * "ps_recv" doesn't include packets not yet read from 177598530Sfenner * the kernel by libpcap. 1776172677Smlaier * 1777172677Smlaier * We maintain the count of packets processed by libpcap in 1778172677Smlaier * "md.packets_read", for reasons described in the comment 1779172677Smlaier * at the end of pcap_read_packet(). We have no idea how many 1780214518Srpaulo * packets were dropped by the kernel buffers -- but we know 1781214518Srpaulo * how many the interface dropped, so we can return that. 178298530Sfenner */ 1783214518Srpaulo 1784172677Smlaier stats->ps_recv = handle->md.packets_read; 1785172677Smlaier stats->ps_drop = 0; 1786214518Srpaulo stats->ps_ifdrop = handle->md.stat.ps_ifdrop; 178775107Sfenner return 0; 178875107Sfenner} 178926175Sfenner 179075107Sfenner/* 1791214518Srpaulo * Get from "/sys/class/net" all interfaces listed there; if they're 1792214518Srpaulo * already in the list of interfaces we have, that won't add another 1793214518Srpaulo * instance, but if they're not, that'll add them. 1794214518Srpaulo * 1795214518Srpaulo * We don't bother getting any addresses for them; it appears you can't 1796214518Srpaulo * use SIOCGIFADDR on Linux to get IPv6 addresses for interfaces, and, 1797214518Srpaulo * although some other types of addresses can be fetched with SIOCGIFADDR, 1798214518Srpaulo * we don't bother with them for now. 1799214518Srpaulo * 1800214518Srpaulo * We also don't fail if we couldn't open "/sys/class/net"; we just leave 1801214518Srpaulo * the list of interfaces as is, and return 0, so that we can try 1802214518Srpaulo * scanning /proc/net/dev. 1803214518Srpaulo */ 1804214518Srpaulostatic int 1805214518Srpauloscan_sys_class_net(pcap_if_t **devlistp, char *errbuf) 1806214518Srpaulo{ 1807214518Srpaulo DIR *sys_class_net_d; 1808214518Srpaulo int fd; 1809214518Srpaulo struct dirent *ent; 1810214518Srpaulo char *p; 1811214518Srpaulo char name[512]; /* XXX - pick a size */ 1812214518Srpaulo char *q, *saveq; 1813214518Srpaulo struct ifreq ifrflags; 1814214518Srpaulo int ret = 1; 1815214518Srpaulo 1816214518Srpaulo sys_class_net_d = opendir("/sys/class/net"); 1817214518Srpaulo if (sys_class_net_d == NULL && errno == ENOENT) 1818214518Srpaulo return (0); 1819214518Srpaulo 1820214518Srpaulo /* 1821214518Srpaulo * Create a socket from which to fetch interface information. 1822214518Srpaulo */ 1823214518Srpaulo fd = socket(AF_INET, SOCK_DGRAM, 0); 1824214518Srpaulo if (fd < 0) { 1825214518Srpaulo (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 1826214518Srpaulo "socket: %s", pcap_strerror(errno)); 1827214518Srpaulo return (-1); 1828214518Srpaulo } 1829214518Srpaulo 1830214518Srpaulo for (;;) { 1831214518Srpaulo errno = 0; 1832214518Srpaulo ent = readdir(sys_class_net_d); 1833214518Srpaulo if (ent == NULL) { 1834214518Srpaulo /* 1835214518Srpaulo * Error or EOF; if errno != 0, it's an error. 1836214518Srpaulo */ 1837214518Srpaulo break; 1838214518Srpaulo } 1839214518Srpaulo 1840214518Srpaulo /* 1841214518Srpaulo * Ignore directories (".", "..", and any subdirectories). 1842214518Srpaulo */ 1843214518Srpaulo if (ent->d_type == DT_DIR) 1844214518Srpaulo continue; 1845214518Srpaulo 1846214518Srpaulo /* 1847214518Srpaulo * Get the interface name. 1848214518Srpaulo */ 1849214518Srpaulo p = &ent->d_name[0]; 1850214518Srpaulo q = &name[0]; 1851214518Srpaulo while (*p != '\0' && isascii(*p) && !isspace(*p)) { 1852214518Srpaulo if (*p == ':') { 1853214518Srpaulo /* 1854214518Srpaulo * This could be the separator between a 1855214518Srpaulo * name and an alias number, or it could be 1856214518Srpaulo * the separator between a name with no 1857214518Srpaulo * alias number and the next field. 1858214518Srpaulo * 1859214518Srpaulo * If there's a colon after digits, it 1860214518Srpaulo * separates the name and the alias number, 1861214518Srpaulo * otherwise it separates the name and the 1862214518Srpaulo * next field. 1863214518Srpaulo */ 1864214518Srpaulo saveq = q; 1865214518Srpaulo while (isascii(*p) && isdigit(*p)) 1866214518Srpaulo *q++ = *p++; 1867214518Srpaulo if (*p != ':') { 1868214518Srpaulo /* 1869214518Srpaulo * That was the next field, 1870214518Srpaulo * not the alias number. 1871214518Srpaulo */ 1872214518Srpaulo q = saveq; 1873214518Srpaulo } 1874214518Srpaulo break; 1875214518Srpaulo } else 1876214518Srpaulo *q++ = *p++; 1877214518Srpaulo } 1878214518Srpaulo *q = '\0'; 1879214518Srpaulo 1880214518Srpaulo /* 1881214518Srpaulo * Get the flags for this interface, and skip it if 1882214518Srpaulo * it's not up. 1883214518Srpaulo */ 1884214518Srpaulo strncpy(ifrflags.ifr_name, name, sizeof(ifrflags.ifr_name)); 1885214518Srpaulo if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) { 1886214518Srpaulo if (errno == ENXIO) 1887214518Srpaulo continue; 1888214518Srpaulo (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 1889214518Srpaulo "SIOCGIFFLAGS: %.*s: %s", 1890214518Srpaulo (int)sizeof(ifrflags.ifr_name), 1891214518Srpaulo ifrflags.ifr_name, 1892214518Srpaulo pcap_strerror(errno)); 1893214518Srpaulo ret = -1; 1894214518Srpaulo break; 1895214518Srpaulo } 1896214518Srpaulo if (!(ifrflags.ifr_flags & IFF_UP)) 1897214518Srpaulo continue; 1898214518Srpaulo 1899214518Srpaulo /* 1900214518Srpaulo * Add an entry for this interface, with no addresses. 1901214518Srpaulo */ 1902214518Srpaulo if (pcap_add_if(devlistp, name, ifrflags.ifr_flags, NULL, 1903214518Srpaulo errbuf) == -1) { 1904214518Srpaulo /* 1905214518Srpaulo * Failure. 1906214518Srpaulo */ 1907214518Srpaulo ret = -1; 1908214518Srpaulo break; 1909214518Srpaulo } 1910214518Srpaulo } 1911214518Srpaulo if (ret != -1) { 1912214518Srpaulo /* 1913214518Srpaulo * Well, we didn't fail for any other reason; did we 1914214518Srpaulo * fail due to an error reading the directory? 1915214518Srpaulo */ 1916214518Srpaulo if (errno != 0) { 1917214518Srpaulo (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 1918214518Srpaulo "Error reading /sys/class/net: %s", 1919214518Srpaulo pcap_strerror(errno)); 1920214518Srpaulo ret = -1; 1921214518Srpaulo } 1922214518Srpaulo } 1923214518Srpaulo 1924214518Srpaulo (void)close(fd); 1925214518Srpaulo (void)closedir(sys_class_net_d); 1926214518Srpaulo return (ret); 1927214518Srpaulo} 1928214518Srpaulo 1929214518Srpaulo/* 1930214518Srpaulo * Get from "/proc/net/dev" all interfaces listed there; if they're 1931214518Srpaulo * already in the list of interfaces we have, that won't add another 1932214518Srpaulo * instance, but if they're not, that'll add them. 1933214518Srpaulo * 1934214518Srpaulo * See comments from scan_sys_class_net(). 1935214518Srpaulo */ 1936214518Srpaulostatic int 1937214518Srpauloscan_proc_net_dev(pcap_if_t **devlistp, char *errbuf) 1938214518Srpaulo{ 1939214518Srpaulo FILE *proc_net_f; 1940214518Srpaulo int fd; 1941214518Srpaulo char linebuf[512]; 1942214518Srpaulo int linenum; 1943214518Srpaulo char *p; 1944214518Srpaulo char name[512]; /* XXX - pick a size */ 1945214518Srpaulo char *q, *saveq; 1946214518Srpaulo struct ifreq ifrflags; 1947214518Srpaulo int ret = 0; 1948214518Srpaulo 1949214518Srpaulo proc_net_f = fopen("/proc/net/dev", "r"); 1950214518Srpaulo if (proc_net_f == NULL && errno == ENOENT) 1951214518Srpaulo return (0); 1952214518Srpaulo 1953214518Srpaulo /* 1954214518Srpaulo * Create a socket from which to fetch interface information. 1955214518Srpaulo */ 1956214518Srpaulo fd = socket(AF_INET, SOCK_DGRAM, 0); 1957214518Srpaulo if (fd < 0) { 1958214518Srpaulo (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 1959214518Srpaulo "socket: %s", pcap_strerror(errno)); 1960214518Srpaulo return (-1); 1961214518Srpaulo } 1962214518Srpaulo 1963214518Srpaulo for (linenum = 1; 1964214518Srpaulo fgets(linebuf, sizeof linebuf, proc_net_f) != NULL; linenum++) { 1965214518Srpaulo /* 1966214518Srpaulo * Skip the first two lines - they're headers. 1967214518Srpaulo */ 1968214518Srpaulo if (linenum <= 2) 1969214518Srpaulo continue; 1970214518Srpaulo 1971214518Srpaulo p = &linebuf[0]; 1972214518Srpaulo 1973214518Srpaulo /* 1974214518Srpaulo * Skip leading white space. 1975214518Srpaulo */ 1976214518Srpaulo while (*p != '\0' && isascii(*p) && isspace(*p)) 1977214518Srpaulo p++; 1978214518Srpaulo if (*p == '\0' || *p == '\n') 1979214518Srpaulo continue; /* blank line */ 1980214518Srpaulo 1981214518Srpaulo /* 1982214518Srpaulo * Get the interface name. 1983214518Srpaulo */ 1984214518Srpaulo q = &name[0]; 1985214518Srpaulo while (*p != '\0' && isascii(*p) && !isspace(*p)) { 1986214518Srpaulo if (*p == ':') { 1987214518Srpaulo /* 1988214518Srpaulo * This could be the separator between a 1989214518Srpaulo * name and an alias number, or it could be 1990214518Srpaulo * the separator between a name with no 1991214518Srpaulo * alias number and the next field. 1992214518Srpaulo * 1993214518Srpaulo * If there's a colon after digits, it 1994214518Srpaulo * separates the name and the alias number, 1995214518Srpaulo * otherwise it separates the name and the 1996214518Srpaulo * next field. 1997214518Srpaulo */ 1998214518Srpaulo saveq = q; 1999214518Srpaulo while (isascii(*p) && isdigit(*p)) 2000214518Srpaulo *q++ = *p++; 2001214518Srpaulo if (*p != ':') { 2002214518Srpaulo /* 2003214518Srpaulo * That was the next field, 2004214518Srpaulo * not the alias number. 2005214518Srpaulo */ 2006214518Srpaulo q = saveq; 2007214518Srpaulo } 2008214518Srpaulo break; 2009214518Srpaulo } else 2010214518Srpaulo *q++ = *p++; 2011214518Srpaulo } 2012214518Srpaulo *q = '\0'; 2013214518Srpaulo 2014214518Srpaulo /* 2015214518Srpaulo * Get the flags for this interface, and skip it if 2016214518Srpaulo * it's not up. 2017214518Srpaulo */ 2018214518Srpaulo strncpy(ifrflags.ifr_name, name, sizeof(ifrflags.ifr_name)); 2019214518Srpaulo if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) { 2020214518Srpaulo if (errno == ENXIO) 2021214518Srpaulo continue; 2022214518Srpaulo (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 2023214518Srpaulo "SIOCGIFFLAGS: %.*s: %s", 2024214518Srpaulo (int)sizeof(ifrflags.ifr_name), 2025214518Srpaulo ifrflags.ifr_name, 2026214518Srpaulo pcap_strerror(errno)); 2027214518Srpaulo ret = -1; 2028214518Srpaulo break; 2029214518Srpaulo } 2030214518Srpaulo if (!(ifrflags.ifr_flags & IFF_UP)) 2031214518Srpaulo continue; 2032214518Srpaulo 2033214518Srpaulo /* 2034214518Srpaulo * Add an entry for this interface, with no addresses. 2035214518Srpaulo */ 2036214518Srpaulo if (pcap_add_if(devlistp, name, ifrflags.ifr_flags, NULL, 2037214518Srpaulo errbuf) == -1) { 2038214518Srpaulo /* 2039214518Srpaulo * Failure. 2040214518Srpaulo */ 2041214518Srpaulo ret = -1; 2042214518Srpaulo break; 2043214518Srpaulo } 2044214518Srpaulo } 2045214518Srpaulo if (ret != -1) { 2046214518Srpaulo /* 2047214518Srpaulo * Well, we didn't fail for any other reason; did we 2048214518Srpaulo * fail due to an error reading the file? 2049214518Srpaulo */ 2050214518Srpaulo if (ferror(proc_net_f)) { 2051214518Srpaulo (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 2052214518Srpaulo "Error reading /proc/net/dev: %s", 2053214518Srpaulo pcap_strerror(errno)); 2054214518Srpaulo ret = -1; 2055214518Srpaulo } 2056214518Srpaulo } 2057214518Srpaulo 2058214518Srpaulo (void)close(fd); 2059214518Srpaulo (void)fclose(proc_net_f); 2060214518Srpaulo return (ret); 2061214518Srpaulo} 2062214518Srpaulo 2063214518Srpaulo/* 2064127664Sbms * Description string for the "any" device. 206575107Sfenner */ 2066127664Sbmsstatic const char any_descr[] = "Pseudo-device that captures on all interfaces"; 2067127664Sbms 206875107Sfennerint 2069127664Sbmspcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf) 207075107Sfenner{ 2071214518Srpaulo int ret; 2072214518Srpaulo 2073214518Srpaulo /* 2074214518Srpaulo * Read "/sys/class/net", and add to the list of interfaces all 2075214518Srpaulo * interfaces listed there that we don't already have, because, 2076214518Srpaulo * on Linux, SIOCGIFCONF reports only interfaces with IPv4 addresses, 2077214518Srpaulo * and even getifaddrs() won't return information about 2078214518Srpaulo * interfaces with no addresses, so you need to read "/sys/class/net" 2079214518Srpaulo * to get the names of the rest of the interfaces. 2080214518Srpaulo */ 2081214518Srpaulo ret = scan_sys_class_net(alldevsp, errbuf); 2082214518Srpaulo if (ret == -1) 2083214518Srpaulo return (-1); /* failed */ 2084214518Srpaulo if (ret == 0) { 2085214518Srpaulo /* 2086214518Srpaulo * No /sys/class/net; try reading /proc/net/dev instead. 2087214518Srpaulo */ 2088214518Srpaulo if (scan_proc_net_dev(alldevsp, errbuf) == -1) 2089214518Srpaulo return (-1); 2090214518Srpaulo } 2091214518Srpaulo 2092214518Srpaulo /* 2093214518Srpaulo * Add the "any" device. 2094214518Srpaulo */ 2095127664Sbms if (pcap_add_if(alldevsp, "any", 0, any_descr, errbuf) < 0) 2096127664Sbms return (-1); 2097127664Sbms 2098127664Sbms#ifdef HAVE_DAG_API 2099214518Srpaulo /* 2100214518Srpaulo * Add DAG devices. 2101214518Srpaulo */ 2102127664Sbms if (dag_platform_finddevs(alldevsp, errbuf) < 0) 2103127664Sbms return (-1); 2104127664Sbms#endif /* HAVE_DAG_API */ 2105127664Sbms 2106147894Ssam#ifdef HAVE_SEPTEL_API 2107214518Srpaulo /* 2108214518Srpaulo * Add Septel devices. 2109214518Srpaulo */ 2110147894Ssam if (septel_platform_finddevs(alldevsp, errbuf) < 0) 2111147894Ssam return (-1); 2112147894Ssam#endif /* HAVE_SEPTEL_API */ 2113147894Ssam 2114214518Srpaulo#ifdef HAVE_SNF_API 2115214518Srpaulo if (snf_platform_finddevs(alldevsp, errbuf) < 0) 2116214518Srpaulo return (-1); 2117214518Srpaulo#endif /* HAVE_SNF_API */ 2118214518Srpaulo 2119190225Srpaulo#ifdef PCAP_SUPPORT_BT 2120214518Srpaulo /* 2121214518Srpaulo * Add Bluetooth devices. 2122214518Srpaulo */ 2123190225Srpaulo if (bt_platform_finddevs(alldevsp, errbuf) < 0) 2124190225Srpaulo return (-1); 2125190225Srpaulo#endif 2126190225Srpaulo 2127190225Srpaulo#ifdef PCAP_SUPPORT_USB 2128214518Srpaulo /* 2129214518Srpaulo * Add USB devices. 2130214518Srpaulo */ 2131190225Srpaulo if (usb_platform_finddevs(alldevsp, errbuf) < 0) 2132190225Srpaulo return (-1); 2133190225Srpaulo#endif 2134190225Srpaulo 2135127664Sbms return (0); 2136127664Sbms} 2137127664Sbms 2138127664Sbms/* 2139127664Sbms * Attach the given BPF code to the packet capture device. 2140127664Sbms */ 2141127664Sbmsstatic int 2142214518Srpaulopcap_setfilter_linux_common(pcap_t *handle, struct bpf_program *filter, 2143214518Srpaulo int is_mmapped) 2144127664Sbms{ 214575107Sfenner#ifdef SO_ATTACH_FILTER 214675107Sfenner struct sock_fprog fcode; 214775107Sfenner int can_filter_in_kernel; 2148127664Sbms int err = 0; 214975107Sfenner#endif 215075107Sfenner 215175107Sfenner if (!handle) 215275107Sfenner return -1; 215375107Sfenner if (!filter) { 215475107Sfenner strncpy(handle->errbuf, "setfilter: No filter specified", 2155190225Srpaulo PCAP_ERRBUF_SIZE); 215675107Sfenner return -1; 215726175Sfenner } 215826175Sfenner 215975107Sfenner /* Make our private copy of the filter */ 216075107Sfenner 2161127664Sbms if (install_bpf_program(handle, filter) < 0) 2162127664Sbms /* install_bpf_program() filled in errbuf */ 216375107Sfenner return -1; 216439291Sfenner 2165127664Sbms /* 2166127664Sbms * Run user level packet filter by default. Will be overriden if 2167127664Sbms * installing a kernel filter succeeds. 216875107Sfenner */ 216975107Sfenner handle->md.use_bpf = 0; 217075107Sfenner 217175107Sfenner /* Install kernel level filter if possible */ 217275107Sfenner 217375107Sfenner#ifdef SO_ATTACH_FILTER 217475107Sfenner#ifdef USHRT_MAX 217575107Sfenner if (handle->fcode.bf_len > USHRT_MAX) { 217675107Sfenner /* 2177127664Sbms * fcode.len is an unsigned short for current kernel. 217875107Sfenner * I have yet to see BPF-Code with that much 217975107Sfenner * instructions but still it is possible. So for the 218075107Sfenner * sake of correctness I added this check. 218175107Sfenner */ 218275107Sfenner fprintf(stderr, "Warning: Filter too complex for kernel\n"); 2183172677Smlaier fcode.len = 0; 218475107Sfenner fcode.filter = NULL; 218575107Sfenner can_filter_in_kernel = 0; 218675107Sfenner } else 218775107Sfenner#endif /* USHRT_MAX */ 218875107Sfenner { 218975107Sfenner /* 219075107Sfenner * Oh joy, the Linux kernel uses struct sock_fprog instead 219175107Sfenner * of struct bpf_program and of course the length field is 219275107Sfenner * of different size. Pointed out by Sebastian 219375107Sfenner * 219475107Sfenner * Oh, and we also need to fix it up so that all "ret" 219575107Sfenner * instructions with non-zero operands have 65535 as the 2196214518Srpaulo * operand if we're not capturing in memory-mapped modee, 2197214518Srpaulo * and so that, if we're in cooked mode, all memory-reference 2198214518Srpaulo * instructions use special magic offsets in references to 2199214518Srpaulo * the link-layer header and assume that the link-layer 2200214518Srpaulo * payload begins at 0; "fix_program()" will do that. 220175107Sfenner */ 2202214518Srpaulo switch (fix_program(handle, &fcode, is_mmapped)) { 220375107Sfenner 220475107Sfenner case -1: 220575107Sfenner default: 220675107Sfenner /* 220775107Sfenner * Fatal error; just quit. 220875107Sfenner * (The "default" case shouldn't happen; we 220975107Sfenner * return -1 for that reason.) 221075107Sfenner */ 221175107Sfenner return -1; 221275107Sfenner 221375107Sfenner case 0: 221475107Sfenner /* 221575107Sfenner * The program performed checks that we can't make 221675107Sfenner * work in the kernel. 221775107Sfenner */ 221875107Sfenner can_filter_in_kernel = 0; 221975107Sfenner break; 222075107Sfenner 222175107Sfenner case 1: 222275107Sfenner /* 222375107Sfenner * We have a filter that'll work in the kernel. 222475107Sfenner */ 222575107Sfenner can_filter_in_kernel = 1; 222675107Sfenner break; 222775107Sfenner } 222839291Sfenner } 222939291Sfenner 223075107Sfenner if (can_filter_in_kernel) { 2231127664Sbms if ((err = set_kernel_filter(handle, &fcode)) == 0) 223275107Sfenner { 223375107Sfenner /* Installation succeded - using kernel filter. */ 223475107Sfenner handle->md.use_bpf = 1; 223575107Sfenner } 2236127664Sbms else if (err == -1) /* Non-fatal error */ 223775107Sfenner { 2238127664Sbms /* 223975107Sfenner * Print a warning if we weren't able to install 224075107Sfenner * the filter for a reason other than "this kernel 224175107Sfenner * isn't configured to support socket filters. 224275107Sfenner */ 224375107Sfenner if (errno != ENOPROTOOPT && errno != EOPNOTSUPP) { 224475107Sfenner fprintf(stderr, 2245127664Sbms "Warning: Kernel filter failed: %s\n", 224675107Sfenner pcap_strerror(errno)); 224775107Sfenner } 224875107Sfenner } 224939291Sfenner } 225039291Sfenner 225175107Sfenner /* 225298530Sfenner * If we're not using the kernel filter, get rid of any kernel 225398530Sfenner * filter that might've been there before, e.g. because the 225498530Sfenner * previous filter could work in the kernel, or because some other 225598530Sfenner * code attached a filter to the socket by some means other than 225698530Sfenner * calling "pcap_setfilter()". Otherwise, the kernel filter may 225798530Sfenner * filter out packets that would pass the new userland filter. 225898530Sfenner */ 225998530Sfenner if (!handle->md.use_bpf) 226098530Sfenner reset_kernel_filter(handle); 226198530Sfenner 226298530Sfenner /* 226375107Sfenner * Free up the copy of the filter that was made by "fix_program()". 226475107Sfenner */ 226575107Sfenner if (fcode.filter != NULL) 226675107Sfenner free(fcode.filter); 2267127664Sbms 2268127664Sbms if (err == -2) 2269127664Sbms /* Fatal error */ 2270127664Sbms return -1; 227175107Sfenner#endif /* SO_ATTACH_FILTER */ 227275107Sfenner 227375107Sfenner return 0; 227475107Sfenner} 227575107Sfenner 2276214518Srpaulostatic int 2277214518Srpaulopcap_setfilter_linux(pcap_t *handle, struct bpf_program *filter) 2278214518Srpaulo{ 2279214518Srpaulo return pcap_setfilter_linux_common(handle, filter, 0); 2280214518Srpaulo} 2281214518Srpaulo 2282214518Srpaulo 228375107Sfenner/* 2284147894Ssam * Set direction flag: Which packets do we accept on a forwarding 2285147894Ssam * single device? IN, OUT or both? 2286147894Ssam */ 2287147894Ssamstatic int 2288162012Ssampcap_setdirection_linux(pcap_t *handle, pcap_direction_t d) 2289147894Ssam{ 2290147894Ssam#ifdef HAVE_PF_PACKET_SOCKETS 2291147894Ssam if (!handle->md.sock_packet) { 2292147894Ssam handle->direction = d; 2293147894Ssam return 0; 2294147894Ssam } 2295147894Ssam#endif 2296147894Ssam /* 2297147894Ssam * We're not using PF_PACKET sockets, so we can't determine 2298147894Ssam * the direction of the packet. 2299147894Ssam */ 2300190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 2301147894Ssam "Setting direction is not supported on SOCK_PACKET sockets"); 2302147894Ssam return -1; 2303147894Ssam} 2304147894Ssam 2305190225Srpaulo 2306190225Srpaulo#ifdef HAVE_PF_PACKET_SOCKETS 2307147894Ssam/* 2308190225Srpaulo * Map the PACKET_ value to a LINUX_SLL_ value; we 2309190225Srpaulo * want the same numerical value to be used in 2310190225Srpaulo * the link-layer header even if the numerical values 2311190225Srpaulo * for the PACKET_ #defines change, so that programs 2312190225Srpaulo * that look at the packet type field will always be 2313190225Srpaulo * able to handle DLT_LINUX_SLL captures. 2314190225Srpaulo */ 2315190225Srpaulostatic short int 2316190225Srpaulomap_packet_type_to_sll_type(short int sll_pkttype) 2317190225Srpaulo{ 2318190225Srpaulo switch (sll_pkttype) { 2319190225Srpaulo 2320190225Srpaulo case PACKET_HOST: 2321190225Srpaulo return htons(LINUX_SLL_HOST); 2322190225Srpaulo 2323190225Srpaulo case PACKET_BROADCAST: 2324190225Srpaulo return htons(LINUX_SLL_BROADCAST); 2325190225Srpaulo 2326190225Srpaulo case PACKET_MULTICAST: 2327190225Srpaulo return htons(LINUX_SLL_MULTICAST); 2328190225Srpaulo 2329190225Srpaulo case PACKET_OTHERHOST: 2330190225Srpaulo return htons(LINUX_SLL_OTHERHOST); 2331190225Srpaulo 2332190225Srpaulo case PACKET_OUTGOING: 2333190225Srpaulo return htons(LINUX_SLL_OUTGOING); 2334190225Srpaulo 2335190225Srpaulo default: 2336190225Srpaulo return -1; 2337190225Srpaulo } 2338190225Srpaulo} 2339190225Srpaulo#endif 2340190225Srpaulo 2341190225Srpaulo/* 2342127664Sbms * Linux uses the ARP hardware type to identify the type of an 2343127664Sbms * interface. pcap uses the DLT_xxx constants for this. This 234498530Sfenner * function takes a pointer to a "pcap_t", and an ARPHRD_xxx 234598530Sfenner * constant, as arguments, and sets "handle->linktype" to the 234698530Sfenner * appropriate DLT_XXX constant and sets "handle->offset" to 234798530Sfenner * the appropriate value (to make "handle->offset" plus link-layer 234898530Sfenner * header length be a multiple of 4, so that the link-layer payload 234998530Sfenner * will be aligned on a 4-byte boundary when capturing packets). 235098530Sfenner * (If the offset isn't set here, it'll be 0; add code as appropriate 235198530Sfenner * for cases where it shouldn't be 0.) 2352127664Sbms * 2353127664Sbms * If "cooked_ok" is non-zero, we can use DLT_LINUX_SLL and capture 2354127664Sbms * in cooked mode; otherwise, we can't use cooked mode, so we have 2355127664Sbms * to pick some type that works in raw mode, or fail. 2356127664Sbms * 235798530Sfenner * Sets the link type to -1 if unable to map the type. 235875107Sfenner */ 2359127664Sbmsstatic void map_arphrd_to_dlt(pcap_t *handle, int arptype, int cooked_ok) 236075107Sfenner{ 236175107Sfenner switch (arptype) { 236298530Sfenner 236339291Sfenner case ARPHRD_ETHER: 2364146768Ssam /* 2365146768Ssam * This is (presumably) a real Ethernet capture; give it a 2366146768Ssam * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so 2367146768Ssam * that an application can let you choose it, in case you're 2368146768Ssam * capturing DOCSIS traffic that a Cisco Cable Modem 2369146768Ssam * Termination System is putting out onto an Ethernet (it 2370146768Ssam * doesn't put an Ethernet header onto the wire, it puts raw 2371146768Ssam * DOCSIS frames out on the wire inside the low-level 2372146768Ssam * Ethernet framing). 2373146768Ssam * 2374146768Ssam * XXX - are there any sorts of "fake Ethernet" that have 2375146768Ssam * ARPHRD_ETHER but that *shouldn't offer DLT_DOCSIS as 2376146768Ssam * a Cisco CMTS won't put traffic onto it or get traffic 2377190225Srpaulo * bridged onto it? ISDN is handled in "activate_new()", 2378146768Ssam * as we fall back on cooked mode there; are there any 2379146768Ssam * others? 2380146768Ssam */ 2381146768Ssam handle->dlt_list = (u_int *) malloc(sizeof(u_int) * 2); 2382146768Ssam /* 2383146768Ssam * If that fails, just leave the list empty. 2384146768Ssam */ 2385146768Ssam if (handle->dlt_list != NULL) { 2386146768Ssam handle->dlt_list[0] = DLT_EN10MB; 2387146768Ssam handle->dlt_list[1] = DLT_DOCSIS; 2388146768Ssam handle->dlt_count = 2; 2389146768Ssam } 2390146768Ssam /* FALLTHROUGH */ 2391146768Ssam 239239291Sfenner case ARPHRD_METRICOM: 239398530Sfenner case ARPHRD_LOOPBACK: 239498530Sfenner handle->linktype = DLT_EN10MB; 239598530Sfenner handle->offset = 2; 239698530Sfenner break; 239798530Sfenner 239898530Sfenner case ARPHRD_EETHER: 239998530Sfenner handle->linktype = DLT_EN3MB; 240098530Sfenner break; 240198530Sfenner 240298530Sfenner case ARPHRD_AX25: 2403190225Srpaulo handle->linktype = DLT_AX25_KISS; 240498530Sfenner break; 240598530Sfenner 240698530Sfenner case ARPHRD_PRONET: 240798530Sfenner handle->linktype = DLT_PRONET; 240898530Sfenner break; 240998530Sfenner 241098530Sfenner case ARPHRD_CHAOS: 241198530Sfenner handle->linktype = DLT_CHAOS; 241298530Sfenner break; 2413214518Srpaulo#ifndef ARPHRD_CAN 2414214518Srpaulo#define ARPHRD_CAN 280 2415214518Srpaulo#endif 2416214518Srpaulo case ARPHRD_CAN: 2417214518Srpaulo handle->linktype = DLT_CAN_SOCKETCAN; 2418214518Srpaulo break; 241998530Sfenner 242075107Sfenner#ifndef ARPHRD_IEEE802_TR 242175107Sfenner#define ARPHRD_IEEE802_TR 800 /* From Linux 2.4 */ 242275107Sfenner#endif 242375107Sfenner case ARPHRD_IEEE802_TR: 242498530Sfenner case ARPHRD_IEEE802: 242598530Sfenner handle->linktype = DLT_IEEE802; 242698530Sfenner handle->offset = 2; 242798530Sfenner break; 242839291Sfenner 242998530Sfenner case ARPHRD_ARCNET: 2430127664Sbms handle->linktype = DLT_ARCNET_LINUX; 243198530Sfenner break; 243298530Sfenner 2433127664Sbms#ifndef ARPHRD_FDDI /* From Linux 2.2.13 */ 2434127664Sbms#define ARPHRD_FDDI 774 2435127664Sbms#endif 243698530Sfenner case ARPHRD_FDDI: 243798530Sfenner handle->linktype = DLT_FDDI; 243898530Sfenner handle->offset = 3; 243998530Sfenner break; 244098530Sfenner 244175107Sfenner#ifndef ARPHRD_ATM /* FIXME: How to #include this? */ 244275107Sfenner#define ARPHRD_ATM 19 244375107Sfenner#endif 244498530Sfenner case ARPHRD_ATM: 244598530Sfenner /* 244698530Sfenner * The Classical IP implementation in ATM for Linux 244798530Sfenner * supports both what RFC 1483 calls "LLC Encapsulation", 244898530Sfenner * in which each packet has an LLC header, possibly 244998530Sfenner * with a SNAP header as well, prepended to it, and 245098530Sfenner * what RFC 1483 calls "VC Based Multiplexing", in which 245198530Sfenner * different virtual circuits carry different network 245298530Sfenner * layer protocols, and no header is prepended to packets. 245398530Sfenner * 245498530Sfenner * They both have an ARPHRD_ type of ARPHRD_ATM, so 245598530Sfenner * you can't use the ARPHRD_ type to find out whether 245698530Sfenner * captured packets will have an LLC header, and, 245798530Sfenner * while there's a socket ioctl to *set* the encapsulation 245898530Sfenner * type, there's no ioctl to *get* the encapsulation type. 245998530Sfenner * 246098530Sfenner * This means that 246198530Sfenner * 246298530Sfenner * programs that dissect Linux Classical IP frames 246398530Sfenner * would have to check for an LLC header and, 246498530Sfenner * depending on whether they see one or not, dissect 246598530Sfenner * the frame as LLC-encapsulated or as raw IP (I 246698530Sfenner * don't know whether there's any traffic other than 246798530Sfenner * IP that would show up on the socket, or whether 246898530Sfenner * there's any support for IPv6 in the Linux 246998530Sfenner * Classical IP code); 247098530Sfenner * 247198530Sfenner * filter expressions would have to compile into 247298530Sfenner * code that checks for an LLC header and does 247398530Sfenner * the right thing. 247498530Sfenner * 247598530Sfenner * Both of those are a nuisance - and, at least on systems 247698530Sfenner * that support PF_PACKET sockets, we don't have to put 247798530Sfenner * up with those nuisances; instead, we can just capture 2478127664Sbms * in cooked mode. That's what we'll do, if we can. 2479127664Sbms * Otherwise, we'll just fail. 248098530Sfenner */ 2481127664Sbms if (cooked_ok) 2482127664Sbms handle->linktype = DLT_LINUX_SLL; 2483127664Sbms else 2484127664Sbms handle->linktype = -1; 248598530Sfenner break; 248639291Sfenner 248798530Sfenner#ifndef ARPHRD_IEEE80211 /* From Linux 2.4.6 */ 248898530Sfenner#define ARPHRD_IEEE80211 801 248998530Sfenner#endif 249098530Sfenner case ARPHRD_IEEE80211: 249198530Sfenner handle->linktype = DLT_IEEE802_11; 249298530Sfenner break; 249398530Sfenner 2494127664Sbms#ifndef ARPHRD_IEEE80211_PRISM /* From Linux 2.4.18 */ 2495127664Sbms#define ARPHRD_IEEE80211_PRISM 802 2496127664Sbms#endif 2497127664Sbms case ARPHRD_IEEE80211_PRISM: 2498127664Sbms handle->linktype = DLT_PRISM_HEADER; 2499127664Sbms break; 2500127664Sbms 2501162012Ssam#ifndef ARPHRD_IEEE80211_RADIOTAP /* new */ 2502162012Ssam#define ARPHRD_IEEE80211_RADIOTAP 803 2503162012Ssam#endif 2504162012Ssam case ARPHRD_IEEE80211_RADIOTAP: 2505162012Ssam handle->linktype = DLT_IEEE802_11_RADIO; 2506162012Ssam break; 2507162012Ssam 250875107Sfenner case ARPHRD_PPP: 250998530Sfenner /* 251098530Sfenner * Some PPP code in the kernel supplies no link-layer 251198530Sfenner * header whatsoever to PF_PACKET sockets; other PPP 251298530Sfenner * code supplies PPP link-layer headers ("syncppp.c"); 251398530Sfenner * some PPP code might supply random link-layer 251498530Sfenner * headers (PPP over ISDN - there's code in Ethereal, 251598530Sfenner * for example, to cope with PPP-over-ISDN captures 251698530Sfenner * with which the Ethereal developers have had to cope, 251798530Sfenner * heuristically trying to determine which of the 251898530Sfenner * oddball link-layer headers particular packets have). 251998530Sfenner * 252098530Sfenner * As such, we just punt, and run all PPP interfaces 2521127664Sbms * in cooked mode, if we can; otherwise, we just treat 2522127664Sbms * it as DLT_RAW, for now - if somebody needs to capture, 2523127664Sbms * on a 2.0[.x] kernel, on PPP devices that supply a 2524127664Sbms * link-layer header, they'll have to add code here to 2525127664Sbms * map to the appropriate DLT_ type (possibly adding a 2526127664Sbms * new DLT_ type, if necessary). 252798530Sfenner */ 2528127664Sbms if (cooked_ok) 2529127664Sbms handle->linktype = DLT_LINUX_SLL; 2530127664Sbms else { 2531127664Sbms /* 2532127664Sbms * XXX - handle ISDN types here? We can't fall 2533127664Sbms * back on cooked sockets, so we'd have to 2534127664Sbms * figure out from the device name what type of 2535127664Sbms * link-layer encapsulation it's using, and map 2536127664Sbms * that to an appropriate DLT_ value, meaning 2537127664Sbms * we'd map "isdnN" devices to DLT_RAW (they 2538127664Sbms * supply raw IP packets with no link-layer 2539127664Sbms * header) and "isdY" devices to a new DLT_I4L_IP 2540127664Sbms * type that has only an Ethernet packet type as 2541127664Sbms * a link-layer header. 2542127664Sbms * 2543127664Sbms * But sometimes we seem to get random crap 2544127664Sbms * in the link-layer header when capturing on 2545127664Sbms * ISDN devices.... 2546127664Sbms */ 2547127664Sbms handle->linktype = DLT_RAW; 2548127664Sbms } 254998530Sfenner break; 255098530Sfenner 2551127664Sbms#ifndef ARPHRD_CISCO 2552127664Sbms#define ARPHRD_CISCO 513 /* previously ARPHRD_HDLC */ 2553127664Sbms#endif 2554127664Sbms case ARPHRD_CISCO: 255598530Sfenner handle->linktype = DLT_C_HDLC; 255698530Sfenner break; 255798530Sfenner 255875107Sfenner /* Not sure if this is correct for all tunnels, but it 255975107Sfenner * works for CIPE */ 256075107Sfenner case ARPHRD_TUNNEL: 256175107Sfenner#ifndef ARPHRD_SIT 2562127664Sbms#define ARPHRD_SIT 776 /* From Linux 2.2.13 */ 256375107Sfenner#endif 256475107Sfenner case ARPHRD_SIT: 256575107Sfenner case ARPHRD_CSLIP: 256675107Sfenner case ARPHRD_SLIP6: 256775107Sfenner case ARPHRD_CSLIP6: 256898530Sfenner case ARPHRD_ADAPT: 256998530Sfenner case ARPHRD_SLIP: 2570127664Sbms#ifndef ARPHRD_RAWHDLC 2571127664Sbms#define ARPHRD_RAWHDLC 518 2572127664Sbms#endif 2573127664Sbms case ARPHRD_RAWHDLC: 2574127664Sbms#ifndef ARPHRD_DLCI 2575127664Sbms#define ARPHRD_DLCI 15 2576127664Sbms#endif 2577127664Sbms case ARPHRD_DLCI: 257898530Sfenner /* 257998530Sfenner * XXX - should some of those be mapped to DLT_LINUX_SLL 258098530Sfenner * instead? Should we just map all of them to DLT_LINUX_SLL? 258198530Sfenner */ 258298530Sfenner handle->linktype = DLT_RAW; 258398530Sfenner break; 258498530Sfenner 2585127664Sbms#ifndef ARPHRD_FRAD 2586127664Sbms#define ARPHRD_FRAD 770 2587127664Sbms#endif 2588127664Sbms case ARPHRD_FRAD: 2589127664Sbms handle->linktype = DLT_FRELAY; 2590127664Sbms break; 2591127664Sbms 259298530Sfenner case ARPHRD_LOCALTLK: 259398530Sfenner handle->linktype = DLT_LTALK; 259498530Sfenner break; 259598530Sfenner 2596127664Sbms#ifndef ARPHRD_FCPP 2597127664Sbms#define ARPHRD_FCPP 784 2598127664Sbms#endif 2599127664Sbms case ARPHRD_FCPP: 2600127664Sbms#ifndef ARPHRD_FCAL 2601127664Sbms#define ARPHRD_FCAL 785 2602127664Sbms#endif 2603127664Sbms case ARPHRD_FCAL: 2604127664Sbms#ifndef ARPHRD_FCPL 2605127664Sbms#define ARPHRD_FCPL 786 2606127664Sbms#endif 2607127664Sbms case ARPHRD_FCPL: 2608127664Sbms#ifndef ARPHRD_FCFABRIC 2609127664Sbms#define ARPHRD_FCFABRIC 787 2610127664Sbms#endif 2611127664Sbms case ARPHRD_FCFABRIC: 2612127664Sbms /* 2613127664Sbms * We assume that those all mean RFC 2625 IP-over- 2614127664Sbms * Fibre Channel, with the RFC 2625 header at 2615127664Sbms * the beginning of the packet. 2616127664Sbms */ 2617127664Sbms handle->linktype = DLT_IP_OVER_FC; 2618127664Sbms break; 2619127664Sbms 2620146768Ssam#ifndef ARPHRD_IRDA 2621146768Ssam#define ARPHRD_IRDA 783 2622146768Ssam#endif 2623127664Sbms case ARPHRD_IRDA: 2624127664Sbms /* Don't expect IP packet out of this interfaces... */ 2625127664Sbms handle->linktype = DLT_LINUX_IRDA; 2626127664Sbms /* We need to save packet direction for IrDA decoding, 2627127664Sbms * so let's use "Linux-cooked" mode. Jean II */ 2628127664Sbms //handle->md.cooked = 1; 2629127664Sbms break; 2630127664Sbms 2631172677Smlaier /* ARPHRD_LAPD is unofficial and randomly allocated, if reallocation 2632172677Smlaier * is needed, please report it to <daniele@orlandi.com> */ 2633172677Smlaier#ifndef ARPHRD_LAPD 2634172677Smlaier#define ARPHRD_LAPD 8445 2635172677Smlaier#endif 2636172677Smlaier case ARPHRD_LAPD: 2637172677Smlaier /* Don't expect IP packet out of this interfaces... */ 2638172677Smlaier handle->linktype = DLT_LINUX_LAPD; 2639172677Smlaier break; 2640172677Smlaier 2641190225Srpaulo#ifndef ARPHRD_NONE 2642190225Srpaulo#define ARPHRD_NONE 0xFFFE 2643190225Srpaulo#endif 2644190225Srpaulo case ARPHRD_NONE: 2645190225Srpaulo /* 2646190225Srpaulo * No link-layer header; packets are just IP 2647190225Srpaulo * packets, so use DLT_RAW. 2648190225Srpaulo */ 2649190225Srpaulo handle->linktype = DLT_RAW; 2650190225Srpaulo break; 2651190225Srpaulo 265298530Sfenner default: 265398530Sfenner handle->linktype = -1; 265498530Sfenner break; 265575107Sfenner } 265675107Sfenner} 265739291Sfenner 265875107Sfenner/* ===== Functions to interface to the newer kernels ================== */ 265939291Sfenner 266075107Sfenner/* 2661190225Srpaulo * Try to open a packet socket using the new kernel PF_PACKET interface. 2662190225Srpaulo * Returns 1 on success, 0 on an error that means the new interface isn't 2663190225Srpaulo * present (so the old SOCK_PACKET interface should be tried), and a 2664190225Srpaulo * PCAP_ERROR_ value on an error that means that the old mechanism won't 2665190225Srpaulo * work either (so it shouldn't be tried). 266675107Sfenner */ 266775107Sfennerstatic int 2668190225Srpauloactivate_new(pcap_t *handle) 266975107Sfenner{ 267075107Sfenner#ifdef HAVE_PF_PACKET_SOCKETS 2671214518Srpaulo const char *device = handle->opt.source; 2672214518Srpaulo int is_any_device = (strcmp(device, "any") == 0); 2673214518Srpaulo int sock_fd = -1, arptype; 2674214518Srpaulo#ifdef HAVE_PACKET_AUXDATA 2675214518Srpaulo int val; 2676214518Srpaulo#endif 2677190225Srpaulo int err = 0; 267875107Sfenner struct packet_mreq mr; 267939291Sfenner 2680190225Srpaulo /* 2681214518Srpaulo * Open a socket with protocol family packet. If the 2682214518Srpaulo * "any" device was specified, we open a SOCK_DGRAM 2683214518Srpaulo * socket for the cooked interface, otherwise we first 2684214518Srpaulo * try a SOCK_RAW socket for the raw interface. 2685190225Srpaulo */ 2686214518Srpaulo sock_fd = is_any_device ? 2687214518Srpaulo socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_ALL)) : 2688214518Srpaulo socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL)); 268939291Sfenner 2690190225Srpaulo if (sock_fd == -1) { 2691190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "socket: %s", 2692190225Srpaulo pcap_strerror(errno) ); 2693190225Srpaulo return 0; /* try old mechanism */ 2694190225Srpaulo } 269539291Sfenner 2696190225Srpaulo /* It seems the kernel supports the new interface. */ 2697190225Srpaulo handle->md.sock_packet = 0; 269839291Sfenner 2699190225Srpaulo /* 2700190225Srpaulo * Get the interface index of the loopback device. 2701190225Srpaulo * If the attempt fails, don't fail, just set the 2702190225Srpaulo * "md.lo_ifindex" to -1. 2703190225Srpaulo * 2704190225Srpaulo * XXX - can there be more than one device that loops 2705190225Srpaulo * packets back, i.e. devices other than "lo"? If so, 2706190225Srpaulo * we'd need to find them all, and have an array of 2707190225Srpaulo * indices for them, and check all of them in 2708190225Srpaulo * "pcap_read_packet()". 2709190225Srpaulo */ 2710190225Srpaulo handle->md.lo_ifindex = iface_get_id(sock_fd, "lo", handle->errbuf); 271175107Sfenner 2712190225Srpaulo /* 2713190225Srpaulo * Default value for offset to align link-layer payload 2714190225Srpaulo * on a 4-byte boundary. 2715190225Srpaulo */ 2716190225Srpaulo handle->offset = 0; 271775107Sfenner 2718190225Srpaulo /* 2719190225Srpaulo * What kind of frames do we have to deal with? Fall back 2720190225Srpaulo * to cooked mode if we have an unknown interface type 2721190225Srpaulo * or a type we know doesn't work well in raw mode. 2722190225Srpaulo */ 2723214518Srpaulo if (!is_any_device) { 2724190225Srpaulo /* Assume for now we don't need cooked mode. */ 2725190225Srpaulo handle->md.cooked = 0; 272698530Sfenner 2727190225Srpaulo if (handle->opt.rfmon) { 2728190225Srpaulo /* 2729190225Srpaulo * We were asked to turn on monitor mode. 2730190225Srpaulo * Do so before we get the link-layer type, 2731190225Srpaulo * because entering monitor mode could change 2732190225Srpaulo * the link-layer type. 2733190225Srpaulo */ 2734214518Srpaulo err = enter_rfmon_mode(handle, sock_fd, device); 2735190225Srpaulo if (err < 0) { 2736190225Srpaulo /* Hard failure */ 2737190225Srpaulo close(sock_fd); 2738190225Srpaulo return err; 2739127664Sbms } 2740190225Srpaulo if (err == 0) { 274175107Sfenner /* 2742190225Srpaulo * Nothing worked for turning monitor mode 2743190225Srpaulo * on. 274475107Sfenner */ 2745190225Srpaulo close(sock_fd); 2746190225Srpaulo return PCAP_ERROR_RFMON_NOTSUP; 2747190225Srpaulo } 2748214518Srpaulo 2749214518Srpaulo /* 2750214518Srpaulo * Either monitor mode has been turned on for 2751214518Srpaulo * the device, or we've been given a different 2752214518Srpaulo * device to open for monitor mode. If we've 2753214518Srpaulo * been given a different device, use it. 2754214518Srpaulo */ 2755214518Srpaulo if (handle->md.mondevice != NULL) 2756214518Srpaulo device = handle->md.mondevice; 2757190225Srpaulo } 2758190225Srpaulo arptype = iface_get_arptype(sock_fd, device, handle->errbuf); 2759190225Srpaulo if (arptype < 0) { 2760190225Srpaulo close(sock_fd); 2761190225Srpaulo return arptype; 2762190225Srpaulo } 2763190225Srpaulo map_arphrd_to_dlt(handle, arptype, 1); 2764190225Srpaulo if (handle->linktype == -1 || 2765190225Srpaulo handle->linktype == DLT_LINUX_SLL || 2766190225Srpaulo handle->linktype == DLT_LINUX_IRDA || 2767190225Srpaulo handle->linktype == DLT_LINUX_LAPD || 2768190225Srpaulo (handle->linktype == DLT_EN10MB && 2769190225Srpaulo (strncmp("isdn", device, 4) == 0 || 2770190225Srpaulo strncmp("isdY", device, 4) == 0))) { 2771190225Srpaulo /* 2772190225Srpaulo * Unknown interface type (-1), or a 2773190225Srpaulo * device we explicitly chose to run 2774190225Srpaulo * in cooked mode (e.g., PPP devices), 2775190225Srpaulo * or an ISDN device (whose link-layer 2776190225Srpaulo * type we can only determine by using 2777190225Srpaulo * APIs that may be different on different 2778190225Srpaulo * kernels) - reopen in cooked mode. 2779190225Srpaulo */ 2780190225Srpaulo if (close(sock_fd) == -1) { 2781190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 2782190225Srpaulo "close: %s", pcap_strerror(errno)); 2783190225Srpaulo return PCAP_ERROR; 2784190225Srpaulo } 2785190225Srpaulo sock_fd = socket(PF_PACKET, SOCK_DGRAM, 2786190225Srpaulo htons(ETH_P_ALL)); 2787190225Srpaulo if (sock_fd == -1) { 2788190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 2789190225Srpaulo "socket: %s", pcap_strerror(errno)); 2790190225Srpaulo return PCAP_ERROR; 2791190225Srpaulo } 2792190225Srpaulo handle->md.cooked = 1; 279375107Sfenner 2794190225Srpaulo /* 2795190225Srpaulo * Get rid of any link-layer type list 2796190225Srpaulo * we allocated - this only supports cooked 2797190225Srpaulo * capture. 2798190225Srpaulo */ 2799190225Srpaulo if (handle->dlt_list != NULL) { 2800190225Srpaulo free(handle->dlt_list); 2801190225Srpaulo handle->dlt_list = NULL; 2802190225Srpaulo handle->dlt_count = 0; 2803190225Srpaulo } 2804190225Srpaulo 2805190225Srpaulo if (handle->linktype == -1) { 2806146768Ssam /* 2807190225Srpaulo * Warn that we're falling back on 2808190225Srpaulo * cooked mode; we may want to 2809190225Srpaulo * update "map_arphrd_to_dlt()" 2810190225Srpaulo * to handle the new type. 2811146768Ssam */ 2812190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 2813190225Srpaulo "arptype %d not " 2814190225Srpaulo "supported by libpcap - " 2815190225Srpaulo "falling back to cooked " 2816190225Srpaulo "socket", 2817190225Srpaulo arptype); 281875107Sfenner } 281975107Sfenner 282075107Sfenner /* 2821190225Srpaulo * IrDA capture is not a real "cooked" capture, 2822190225Srpaulo * it's IrLAP frames, not IP packets. The 2823190225Srpaulo * same applies to LAPD capture. 282475107Sfenner */ 2825190225Srpaulo if (handle->linktype != DLT_LINUX_IRDA && 2826190225Srpaulo handle->linktype != DLT_LINUX_LAPD) 2827190225Srpaulo handle->linktype = DLT_LINUX_SLL; 2828190225Srpaulo } 282975107Sfenner 2830190225Srpaulo handle->md.ifindex = iface_get_id(sock_fd, device, 2831190225Srpaulo handle->errbuf); 2832190225Srpaulo if (handle->md.ifindex == -1) { 2833190225Srpaulo close(sock_fd); 2834190225Srpaulo return PCAP_ERROR; 283575107Sfenner } 283675107Sfenner 2837190225Srpaulo if ((err = iface_bind(sock_fd, handle->md.ifindex, 2838190225Srpaulo handle->errbuf)) != 1) { 2839190225Srpaulo close(sock_fd); 2840190225Srpaulo if (err < 0) 2841190225Srpaulo return err; 2842190225Srpaulo else 2843190225Srpaulo return 0; /* try old mechanism */ 2844190225Srpaulo } 2845190225Srpaulo } else { 2846127664Sbms /* 2847214518Srpaulo * The "any" device. 2848127664Sbms */ 2849214518Srpaulo if (handle->opt.rfmon) { 2850214518Srpaulo /* 2851214518Srpaulo * It doesn't support monitor mode. 2852214518Srpaulo */ 2853214518Srpaulo return PCAP_ERROR_RFMON_NOTSUP; 2854214518Srpaulo } 2855214518Srpaulo 2856214518Srpaulo /* 2857214518Srpaulo * It uses cooked mode. 2858214518Srpaulo */ 2859190225Srpaulo handle->md.cooked = 1; 2860190225Srpaulo handle->linktype = DLT_LINUX_SLL; 286175107Sfenner 2862127664Sbms /* 2863190225Srpaulo * We're not bound to a device. 2864190225Srpaulo * For now, we're using this as an indication 2865190225Srpaulo * that we can't transmit; stop doing that only 2866190225Srpaulo * if we figure out how to transmit in cooked 2867190225Srpaulo * mode. 286875107Sfenner */ 2869190225Srpaulo handle->md.ifindex = -1; 2870190225Srpaulo } 287175107Sfenner 2872190225Srpaulo /* 2873190225Srpaulo * Select promiscuous mode on if "promisc" is set. 2874190225Srpaulo * 2875190225Srpaulo * Do not turn allmulti mode on if we don't select 2876190225Srpaulo * promiscuous mode - on some devices (e.g., Orinoco 2877190225Srpaulo * wireless interfaces), allmulti mode isn't supported 2878190225Srpaulo * and the driver implements it by turning promiscuous 2879190225Srpaulo * mode on, and that screws up the operation of the 2880190225Srpaulo * card as a normal networking interface, and on no 2881190225Srpaulo * other platform I know of does starting a non- 2882190225Srpaulo * promiscuous capture affect which multicast packets 2883190225Srpaulo * are received by the interface. 2884190225Srpaulo */ 288539291Sfenner 2886190225Srpaulo /* 2887190225Srpaulo * Hmm, how can we set promiscuous mode on all interfaces? 2888214518Srpaulo * I am not sure if that is possible at all. For now, we 2889214518Srpaulo * silently ignore attempts to turn promiscuous mode on 2890214518Srpaulo * for the "any" device (so you don't have to explicitly 2891214518Srpaulo * disable it in programs such as tcpdump). 2892190225Srpaulo */ 289375107Sfenner 2894214518Srpaulo if (!is_any_device && handle->opt.promisc) { 2895190225Srpaulo memset(&mr, 0, sizeof(mr)); 2896190225Srpaulo mr.mr_ifindex = handle->md.ifindex; 2897190225Srpaulo mr.mr_type = PACKET_MR_PROMISC; 2898190225Srpaulo if (setsockopt(sock_fd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, 2899190225Srpaulo &mr, sizeof(mr)) == -1) { 2900190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 2901190225Srpaulo "setsockopt: %s", pcap_strerror(errno)); 2902190225Srpaulo close(sock_fd); 2903190225Srpaulo return PCAP_ERROR; 2904190225Srpaulo } 2905190225Srpaulo } 290675107Sfenner 2907190225Srpaulo /* Enable auxillary data if supported and reserve room for 2908190225Srpaulo * reconstructing VLAN headers. */ 2909190225Srpaulo#ifdef HAVE_PACKET_AUXDATA 2910190225Srpaulo val = 1; 2911190225Srpaulo if (setsockopt(sock_fd, SOL_PACKET, PACKET_AUXDATA, &val, 2912190225Srpaulo sizeof(val)) == -1 && errno != ENOPROTOOPT) { 2913190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 2914190225Srpaulo "setsockopt: %s", pcap_strerror(errno)); 2915190225Srpaulo close(sock_fd); 2916190225Srpaulo return PCAP_ERROR; 2917190225Srpaulo } 2918190225Srpaulo handle->offset += VLAN_TAG_LEN; 2919190225Srpaulo#endif /* HAVE_PACKET_AUXDATA */ 292075107Sfenner 2921190225Srpaulo /* 2922190225Srpaulo * This is a 2.2[.x] or later kernel (we know that 2923190225Srpaulo * because we're not using a SOCK_PACKET socket - 2924190225Srpaulo * PF_PACKET is supported only in 2.2 and later 2925190225Srpaulo * kernels). 2926190225Srpaulo * 2927190225Srpaulo * We can safely pass "recvfrom()" a byte count 2928190225Srpaulo * based on the snapshot length. 2929190225Srpaulo * 2930190225Srpaulo * If we're in cooked mode, make the snapshot length 2931190225Srpaulo * large enough to hold a "cooked mode" header plus 2932190225Srpaulo * 1 byte of packet data (so we don't pass a byte 2933190225Srpaulo * count of 0 to "recvfrom()"). 2934190225Srpaulo */ 2935190225Srpaulo if (handle->md.cooked) { 2936190225Srpaulo if (handle->snapshot < SLL_HDR_LEN + 1) 2937190225Srpaulo handle->snapshot = SLL_HDR_LEN + 1; 2938190225Srpaulo } 2939190225Srpaulo handle->bufsize = handle->snapshot; 294075107Sfenner 2941190225Srpaulo /* Save the socket FD in the pcap structure */ 2942190225Srpaulo handle->fd = sock_fd; 2943127664Sbms 2944190225Srpaulo return 1; 294575107Sfenner#else 2946127664Sbms strncpy(ebuf, 2947127664Sbms "New packet capturing interface not supported by build " 294875107Sfenner "environment", PCAP_ERRBUF_SIZE); 294975107Sfenner return 0; 295039291Sfenner#endif 295175107Sfenner} 295239291Sfenner 2953190225Srpaulostatic int 2954190225Srpauloactivate_mmap(pcap_t *handle) 2955190225Srpaulo{ 2956190225Srpaulo#ifdef HAVE_PACKET_RING 2957190225Srpaulo int ret; 2958190225Srpaulo 2959214518Srpaulo /* 2960214518Srpaulo * Attempt to allocate a buffer to hold the contents of one 2961214518Srpaulo * packet, for use by the oneshot callback. 2962214518Srpaulo */ 2963214518Srpaulo handle->md.oneshot_buffer = malloc(handle->snapshot); 2964214518Srpaulo if (handle->md.oneshot_buffer == NULL) { 2965214518Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 2966214518Srpaulo "can't allocate oneshot buffer: %s", 2967214518Srpaulo pcap_strerror(errno)); 2968214518Srpaulo return PCAP_ERROR; 2969214518Srpaulo } 2970214518Srpaulo 2971190225Srpaulo if (handle->opt.buffer_size == 0) { 2972190225Srpaulo /* by default request 2M for the ring buffer */ 2973190225Srpaulo handle->opt.buffer_size = 2*1024*1024; 2974190225Srpaulo } 2975190225Srpaulo ret = prepare_tpacket_socket(handle); 2976214518Srpaulo if (ret != 1) { 2977214518Srpaulo free(handle->md.oneshot_buffer); 2978190225Srpaulo return ret; 2979214518Srpaulo } 2980190225Srpaulo ret = create_ring(handle); 2981214518Srpaulo if (ret != 1) { 2982214518Srpaulo free(handle->md.oneshot_buffer); 2983190225Srpaulo return ret; 2984214518Srpaulo } 2985190225Srpaulo 2986190225Srpaulo /* override some defaults and inherit the other fields from 2987190225Srpaulo * activate_new 2988190225Srpaulo * handle->offset is used to get the current position into the rx ring 2989190225Srpaulo * handle->cc is used to store the ring size */ 2990190225Srpaulo handle->read_op = pcap_read_linux_mmap; 2991190225Srpaulo handle->cleanup_op = pcap_cleanup_linux_mmap; 2992190225Srpaulo handle->setfilter_op = pcap_setfilter_linux_mmap; 2993190225Srpaulo handle->setnonblock_op = pcap_setnonblock_mmap; 2994190225Srpaulo handle->getnonblock_op = pcap_getnonblock_mmap; 2995214518Srpaulo handle->oneshot_callback = pcap_oneshot_mmap; 2996190225Srpaulo handle->selectable_fd = handle->fd; 2997190225Srpaulo return 1; 2998190225Srpaulo#else /* HAVE_PACKET_RING */ 2999190225Srpaulo return 0; 3000190225Srpaulo#endif /* HAVE_PACKET_RING */ 3001190225Srpaulo} 3002190225Srpaulo 3003190225Srpaulo#ifdef HAVE_PACKET_RING 3004190225Srpaulostatic int 3005190225Srpauloprepare_tpacket_socket(pcap_t *handle) 3006190225Srpaulo{ 3007190225Srpaulo#ifdef HAVE_TPACKET2 3008190225Srpaulo socklen_t len; 3009190225Srpaulo int val; 3010190225Srpaulo#endif 3011190225Srpaulo 3012190225Srpaulo handle->md.tp_version = TPACKET_V1; 3013190225Srpaulo handle->md.tp_hdrlen = sizeof(struct tpacket_hdr); 3014190225Srpaulo 3015190225Srpaulo#ifdef HAVE_TPACKET2 3016190225Srpaulo /* Probe whether kernel supports TPACKET_V2 */ 3017190225Srpaulo val = TPACKET_V2; 3018190225Srpaulo len = sizeof(val); 3019190225Srpaulo if (getsockopt(handle->fd, SOL_PACKET, PACKET_HDRLEN, &val, &len) < 0) { 3020190225Srpaulo if (errno == ENOPROTOOPT) 3021214518Srpaulo return 1; /* no - just drive on */ 3022214518Srpaulo 3023214518Srpaulo /* Yes - treat as a failure. */ 3024190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 3025214518Srpaulo "can't get TPACKET_V2 header len on packet socket: %s", 3026214518Srpaulo pcap_strerror(errno)); 3027214518Srpaulo return -1; 3028190225Srpaulo } 3029190225Srpaulo handle->md.tp_hdrlen = val; 3030190225Srpaulo 3031190225Srpaulo val = TPACKET_V2; 3032190225Srpaulo if (setsockopt(handle->fd, SOL_PACKET, PACKET_VERSION, &val, 3033190225Srpaulo sizeof(val)) < 0) { 3034190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 3035214518Srpaulo "can't activate TPACKET_V2 on packet socket: %s", 3036214518Srpaulo pcap_strerror(errno)); 3037214518Srpaulo return -1; 3038190225Srpaulo } 3039190225Srpaulo handle->md.tp_version = TPACKET_V2; 3040190225Srpaulo 3041190225Srpaulo /* Reserve space for VLAN tag reconstruction */ 3042190225Srpaulo val = VLAN_TAG_LEN; 3043190225Srpaulo if (setsockopt(handle->fd, SOL_PACKET, PACKET_RESERVE, &val, 3044190225Srpaulo sizeof(val)) < 0) { 3045190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 3046214518Srpaulo "can't set up reserve on packet socket: %s", 3047214518Srpaulo pcap_strerror(errno)); 3048214518Srpaulo return -1; 3049190225Srpaulo } 3050190225Srpaulo 3051190225Srpaulo#endif /* HAVE_TPACKET2 */ 3052190225Srpaulo return 1; 3053190225Srpaulo} 3054190225Srpaulo 3055190225Srpaulostatic int 3056190225Srpaulocreate_ring(pcap_t *handle) 3057190225Srpaulo{ 3058214518Srpaulo unsigned i, j, frames_per_block; 3059190225Srpaulo struct tpacket_req req; 3060190225Srpaulo 3061190225Srpaulo /* Note that with large snapshot (say 64K) only a few frames 3062190225Srpaulo * will be available in the ring even with pretty large ring size 3063190225Srpaulo * (and a lot of memory will be unused). 3064190225Srpaulo * The snap len should be carefully chosen to achive best 3065190225Srpaulo * performance */ 3066190225Srpaulo req.tp_frame_size = TPACKET_ALIGN(handle->snapshot + 3067190225Srpaulo TPACKET_ALIGN(handle->md.tp_hdrlen) + 3068190225Srpaulo sizeof(struct sockaddr_ll)); 3069190225Srpaulo req.tp_frame_nr = handle->opt.buffer_size/req.tp_frame_size; 3070214518Srpaulo 3071214518Srpaulo /* compute the minumum block size that will handle this frame. 3072214518Srpaulo * The block has to be page size aligned. 3073214518Srpaulo * The max block size allowed by the kernel is arch-dependent and 3074214518Srpaulo * it's not explicitly checked here. */ 3075214518Srpaulo req.tp_block_size = getpagesize(); 3076214518Srpaulo while (req.tp_block_size < req.tp_frame_size) 3077214518Srpaulo req.tp_block_size <<= 1; 3078214518Srpaulo 3079214518Srpaulo frames_per_block = req.tp_block_size/req.tp_frame_size; 3080214518Srpaulo 3081214518Srpaulo /* ask the kernel to create the ring */ 3082214518Srpauloretry: 3083190225Srpaulo req.tp_block_nr = req.tp_frame_nr / frames_per_block; 3084190225Srpaulo 3085190225Srpaulo /* req.tp_frame_nr is requested to match frames_per_block*req.tp_block_nr */ 3086190225Srpaulo req.tp_frame_nr = req.tp_block_nr * frames_per_block; 3087214518Srpaulo 3088190225Srpaulo if (setsockopt(handle->fd, SOL_PACKET, PACKET_RX_RING, 3089190225Srpaulo (void *) &req, sizeof(req))) { 3090190225Srpaulo if ((errno == ENOMEM) && (req.tp_block_nr > 1)) { 3091214518Srpaulo /* 3092214518Srpaulo * Memory failure; try to reduce the requested ring 3093214518Srpaulo * size. 3094214518Srpaulo * 3095214518Srpaulo * We used to reduce this by half -- do 5% instead. 3096214518Srpaulo * That may result in more iterations and a longer 3097214518Srpaulo * startup, but the user will be much happier with 3098214518Srpaulo * the resulting buffer size. 3099214518Srpaulo */ 3100214518Srpaulo if (req.tp_frame_nr < 20) 3101214518Srpaulo req.tp_frame_nr -= 1; 3102214518Srpaulo else 3103214518Srpaulo req.tp_frame_nr -= req.tp_frame_nr/20; 3104190225Srpaulo goto retry; 3105190225Srpaulo } 3106214518Srpaulo if (errno == ENOPROTOOPT) { 3107214518Srpaulo /* 3108214518Srpaulo * We don't have ring buffer support in this kernel. 3109214518Srpaulo */ 3110214518Srpaulo return 0; 3111214518Srpaulo } 3112214518Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 3113214518Srpaulo "can't create rx ring on packet socket: %s", 3114214518Srpaulo pcap_strerror(errno)); 3115214518Srpaulo return -1; 3116190225Srpaulo } 3117190225Srpaulo 3118190225Srpaulo /* memory map the rx ring */ 3119214518Srpaulo handle->md.mmapbuflen = req.tp_block_nr * req.tp_block_size; 3120214518Srpaulo handle->md.mmapbuf = mmap(0, handle->md.mmapbuflen, 3121214518Srpaulo PROT_READ|PROT_WRITE, MAP_SHARED, handle->fd, 0); 3122214518Srpaulo if (handle->md.mmapbuf == MAP_FAILED) { 3123214518Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 3124214518Srpaulo "can't mmap rx ring: %s", pcap_strerror(errno)); 3125190225Srpaulo 3126190225Srpaulo /* clear the allocated ring on error*/ 3127190225Srpaulo destroy_ring(handle); 3128214518Srpaulo return -1; 3129190225Srpaulo } 3130190225Srpaulo 3131190225Srpaulo /* allocate a ring for each frame header pointer*/ 3132190225Srpaulo handle->cc = req.tp_frame_nr; 3133190225Srpaulo handle->buffer = malloc(handle->cc * sizeof(union thdr *)); 3134190225Srpaulo if (!handle->buffer) { 3135214518Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 3136214518Srpaulo "can't allocate ring of frame headers: %s", 3137214518Srpaulo pcap_strerror(errno)); 3138214518Srpaulo 3139190225Srpaulo destroy_ring(handle); 3140214518Srpaulo return -1; 3141190225Srpaulo } 3142190225Srpaulo 3143190225Srpaulo /* fill the header ring with proper frame ptr*/ 3144190225Srpaulo handle->offset = 0; 3145190225Srpaulo for (i=0; i<req.tp_block_nr; ++i) { 3146214518Srpaulo void *base = &handle->md.mmapbuf[i*req.tp_block_size]; 3147190225Srpaulo for (j=0; j<frames_per_block; ++j, ++handle->offset) { 3148190225Srpaulo RING_GET_FRAME(handle) = base; 3149190225Srpaulo base += req.tp_frame_size; 3150190225Srpaulo } 3151190225Srpaulo } 3152190225Srpaulo 3153190225Srpaulo handle->bufsize = req.tp_frame_size; 3154190225Srpaulo handle->offset = 0; 3155190225Srpaulo return 1; 3156190225Srpaulo} 3157190225Srpaulo 3158190225Srpaulo/* free all ring related resources*/ 3159190225Srpaulostatic void 3160190225Srpaulodestroy_ring(pcap_t *handle) 3161190225Srpaulo{ 3162190225Srpaulo /* tell the kernel to destroy the ring*/ 3163190225Srpaulo struct tpacket_req req; 3164190225Srpaulo memset(&req, 0, sizeof(req)); 3165190225Srpaulo setsockopt(handle->fd, SOL_PACKET, PACKET_RX_RING, 3166190225Srpaulo (void *) &req, sizeof(req)); 3167190225Srpaulo 3168190225Srpaulo /* if ring is mapped, unmap it*/ 3169214518Srpaulo if (handle->md.mmapbuf) { 3170214518Srpaulo /* do not test for mmap failure, as we can't recover from any error */ 3171214518Srpaulo munmap(handle->md.mmapbuf, handle->md.mmapbuflen); 3172214518Srpaulo handle->md.mmapbuf = NULL; 3173190225Srpaulo } 3174190225Srpaulo} 3175190225Srpaulo 3176214518Srpaulo/* 3177214518Srpaulo * Special one-shot callback, used for pcap_next() and pcap_next_ex(), 3178214518Srpaulo * for Linux mmapped capture. 3179214518Srpaulo * 3180214518Srpaulo * The problem is that pcap_next() and pcap_next_ex() expect the packet 3181214518Srpaulo * data handed to the callback to be valid after the callback returns, 3182214518Srpaulo * but pcap_read_linux_mmap() has to release that packet as soon as 3183214518Srpaulo * the callback returns (otherwise, the kernel thinks there's still 3184214518Srpaulo * at least one unprocessed packet available in the ring, so a select() 3185214518Srpaulo * will immediately return indicating that there's data to process), so, 3186214518Srpaulo * in the callback, we have to make a copy of the packet. 3187214518Srpaulo * 3188214518Srpaulo * Yes, this means that, if the capture is using the ring buffer, using 3189214518Srpaulo * pcap_next() or pcap_next_ex() requires more copies than using 3190214518Srpaulo * pcap_loop() or pcap_dispatch(). If that bothers you, don't use 3191214518Srpaulo * pcap_next() or pcap_next_ex(). 3192214518Srpaulo */ 3193190225Srpaulostatic void 3194214518Srpaulopcap_oneshot_mmap(u_char *user, const struct pcap_pkthdr *h, 3195214518Srpaulo const u_char *bytes) 3196214518Srpaulo{ 3197214518Srpaulo struct oneshot_userdata *sp = (struct oneshot_userdata *)user; 3198214518Srpaulo 3199214518Srpaulo *sp->hdr = *h; 3200214518Srpaulo memcpy(sp->pd->md.oneshot_buffer, bytes, h->caplen); 3201214518Srpaulo *sp->pkt = sp->pd->md.oneshot_buffer; 3202214518Srpaulo} 3203214518Srpaulo 3204214518Srpaulostatic void 3205190225Srpaulopcap_cleanup_linux_mmap( pcap_t *handle ) 3206190225Srpaulo{ 3207190225Srpaulo destroy_ring(handle); 3208214518Srpaulo if (handle->md.oneshot_buffer != NULL) { 3209214518Srpaulo free(handle->md.oneshot_buffer); 3210214518Srpaulo handle->md.oneshot_buffer = NULL; 3211214518Srpaulo } 3212190225Srpaulo pcap_cleanup_linux(handle); 3213190225Srpaulo} 3214190225Srpaulo 3215190225Srpaulo 3216190225Srpaulostatic int 3217190225Srpaulopcap_getnonblock_mmap(pcap_t *p, char *errbuf) 3218190225Srpaulo{ 3219190225Srpaulo /* use negative value of timeout to indicate non blocking ops */ 3220190225Srpaulo return (p->md.timeout<0); 3221190225Srpaulo} 3222190225Srpaulo 3223190225Srpaulostatic int 3224190225Srpaulopcap_setnonblock_mmap(pcap_t *p, int nonblock, char *errbuf) 3225190225Srpaulo{ 3226190225Srpaulo /* map each value to the corresponding 2's complement, to 3227190225Srpaulo * preserve the timeout value provided with pcap_set_timeout */ 3228190225Srpaulo if (nonblock) { 3229214518Srpaulo if (p->md.timeout >= 0) { 3230214518Srpaulo /* 3231214518Srpaulo * Timeout is non-negative, so we're not already 3232214518Srpaulo * in non-blocking mode; set it to the 2's 3233214518Srpaulo * complement, to make it negative, as an 3234214518Srpaulo * indication that we're in non-blocking mode. 3235214518Srpaulo */ 3236190225Srpaulo p->md.timeout = p->md.timeout*-1 - 1; 3237214518Srpaulo } 3238214518Srpaulo } else { 3239214518Srpaulo if (p->md.timeout < 0) { 3240214518Srpaulo /* 3241214518Srpaulo * Timeout is negative, so we're not already 3242214518Srpaulo * in blocking mode; reverse the previous 3243214518Srpaulo * operation, to make the timeout non-negative 3244214518Srpaulo * again. 3245214518Srpaulo */ 3246190225Srpaulo p->md.timeout = (p->md.timeout+1)*-1; 3247214518Srpaulo } 3248214518Srpaulo } 3249190225Srpaulo return 0; 3250190225Srpaulo} 3251190225Srpaulo 3252190225Srpaulostatic inline union thdr * 3253190225Srpaulopcap_get_ring_frame(pcap_t *handle, int status) 3254190225Srpaulo{ 3255190225Srpaulo union thdr h; 3256190225Srpaulo 3257190225Srpaulo h.raw = RING_GET_FRAME(handle); 3258190225Srpaulo switch (handle->md.tp_version) { 3259190225Srpaulo case TPACKET_V1: 3260190225Srpaulo if (status != (h.h1->tp_status ? TP_STATUS_USER : 3261190225Srpaulo TP_STATUS_KERNEL)) 3262190225Srpaulo return NULL; 3263190225Srpaulo break; 3264190225Srpaulo#ifdef HAVE_TPACKET2 3265190225Srpaulo case TPACKET_V2: 3266190225Srpaulo if (status != (h.h2->tp_status ? TP_STATUS_USER : 3267190225Srpaulo TP_STATUS_KERNEL)) 3268190225Srpaulo return NULL; 3269190225Srpaulo break; 3270190225Srpaulo#endif 3271190225Srpaulo } 3272190225Srpaulo return h.raw; 3273190225Srpaulo} 3274190225Srpaulo 3275214518Srpaulo#ifndef POLLRDHUP 3276214518Srpaulo#define POLLRDHUP 0 3277214518Srpaulo#endif 3278214518Srpaulo 3279190225Srpaulostatic int 3280190225Srpaulopcap_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, 3281190225Srpaulo u_char *user) 3282190225Srpaulo{ 3283214518Srpaulo int timeout; 3284190225Srpaulo int pkts = 0; 3285214518Srpaulo char c; 3286190225Srpaulo 3287190225Srpaulo /* wait for frames availability.*/ 3288214518Srpaulo if (!pcap_get_ring_frame(handle, TP_STATUS_USER)) { 3289190225Srpaulo struct pollfd pollinfo; 3290190225Srpaulo int ret; 3291190225Srpaulo 3292190225Srpaulo pollinfo.fd = handle->fd; 3293190225Srpaulo pollinfo.events = POLLIN; 3294190225Srpaulo 3295214518Srpaulo if (handle->md.timeout == 0) 3296214518Srpaulo timeout = -1; /* block forever */ 3297214518Srpaulo else if (handle->md.timeout > 0) 3298214518Srpaulo timeout = handle->md.timeout; /* block for that amount of time */ 3299214518Srpaulo else 3300214518Srpaulo timeout = 0; /* non-blocking mode - poll to pick up errors */ 3301190225Srpaulo do { 3302214518Srpaulo ret = poll(&pollinfo, 1, timeout); 3303214518Srpaulo if (ret < 0 && errno != EINTR) { 3304190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 3305214518Srpaulo "can't poll on packet socket: %s", 3306214518Srpaulo pcap_strerror(errno)); 3307214518Srpaulo return PCAP_ERROR; 3308214518Srpaulo } else if (ret > 0 && 3309214518Srpaulo (pollinfo.revents & (POLLHUP|POLLRDHUP|POLLERR|POLLNVAL))) { 3310214518Srpaulo /* 3311214518Srpaulo * There's some indication other than 3312214518Srpaulo * "you can read on this descriptor" on 3313214518Srpaulo * the descriptor. 3314214518Srpaulo */ 3315214518Srpaulo if (pollinfo.revents & (POLLHUP | POLLRDHUP)) { 3316214518Srpaulo snprintf(handle->errbuf, 3317214518Srpaulo PCAP_ERRBUF_SIZE, 3318214518Srpaulo "Hangup on packet socket"); 3319214518Srpaulo return PCAP_ERROR; 3320214518Srpaulo } 3321214518Srpaulo if (pollinfo.revents & POLLERR) { 3322214518Srpaulo /* 3323214518Srpaulo * A recv() will give us the 3324214518Srpaulo * actual error code. 3325214518Srpaulo * 3326214518Srpaulo * XXX - make the socket non-blocking? 3327214518Srpaulo */ 3328214518Srpaulo if (recv(handle->fd, &c, sizeof c, 3329214518Srpaulo MSG_PEEK) != -1) 3330214518Srpaulo continue; /* what, no error? */ 3331214518Srpaulo if (errno == ENETDOWN) { 3332214518Srpaulo /* 3333214518Srpaulo * The device on which we're 3334214518Srpaulo * capturing went away. 3335214518Srpaulo * 3336214518Srpaulo * XXX - we should really return 3337214518Srpaulo * PCAP_ERROR_IFACE_NOT_UP, 3338214518Srpaulo * but pcap_dispatch() etc. 3339214518Srpaulo * aren't defined to return 3340214518Srpaulo * that. 3341214518Srpaulo */ 3342214518Srpaulo snprintf(handle->errbuf, 3343214518Srpaulo PCAP_ERRBUF_SIZE, 3344214518Srpaulo "The interface went down"); 3345214518Srpaulo } else { 3346214518Srpaulo snprintf(handle->errbuf, 3347214518Srpaulo PCAP_ERRBUF_SIZE, 3348214518Srpaulo "Error condition on packet socket: %s", 3349214518Srpaulo strerror(errno)); 3350214518Srpaulo } 3351214518Srpaulo return PCAP_ERROR; 3352214518Srpaulo } 3353214518Srpaulo if (pollinfo.revents & POLLNVAL) { 3354214518Srpaulo snprintf(handle->errbuf, 3355214518Srpaulo PCAP_ERRBUF_SIZE, 3356214518Srpaulo "Invalid polling request on packet socket"); 3357214518Srpaulo return PCAP_ERROR; 3358214518Srpaulo } 3359214518Srpaulo } 3360190225Srpaulo /* check for break loop condition on interrupted syscall*/ 3361190225Srpaulo if (handle->break_loop) { 3362190225Srpaulo handle->break_loop = 0; 3363214518Srpaulo return PCAP_ERROR_BREAK; 3364190225Srpaulo } 3365190225Srpaulo } while (ret < 0); 3366190225Srpaulo } 3367190225Srpaulo 3368190225Srpaulo /* non-positive values of max_packets are used to require all 3369190225Srpaulo * packets currently available in the ring */ 3370190225Srpaulo while ((pkts < max_packets) || (max_packets <= 0)) { 3371190225Srpaulo int run_bpf; 3372190225Srpaulo struct sockaddr_ll *sll; 3373190225Srpaulo struct pcap_pkthdr pcaphdr; 3374190225Srpaulo unsigned char *bp; 3375190225Srpaulo union thdr h; 3376190225Srpaulo unsigned int tp_len; 3377190225Srpaulo unsigned int tp_mac; 3378190225Srpaulo unsigned int tp_snaplen; 3379190225Srpaulo unsigned int tp_sec; 3380190225Srpaulo unsigned int tp_usec; 3381190225Srpaulo 3382190225Srpaulo h.raw = pcap_get_ring_frame(handle, TP_STATUS_USER); 3383190225Srpaulo if (!h.raw) 3384190225Srpaulo break; 3385190225Srpaulo 3386190225Srpaulo switch (handle->md.tp_version) { 3387190225Srpaulo case TPACKET_V1: 3388190225Srpaulo tp_len = h.h1->tp_len; 3389190225Srpaulo tp_mac = h.h1->tp_mac; 3390190225Srpaulo tp_snaplen = h.h1->tp_snaplen; 3391190225Srpaulo tp_sec = h.h1->tp_sec; 3392190225Srpaulo tp_usec = h.h1->tp_usec; 3393190225Srpaulo break; 3394190225Srpaulo#ifdef HAVE_TPACKET2 3395190225Srpaulo case TPACKET_V2: 3396190225Srpaulo tp_len = h.h2->tp_len; 3397190225Srpaulo tp_mac = h.h2->tp_mac; 3398190225Srpaulo tp_snaplen = h.h2->tp_snaplen; 3399190225Srpaulo tp_sec = h.h2->tp_sec; 3400190225Srpaulo tp_usec = h.h2->tp_nsec / 1000; 3401190225Srpaulo break; 3402190225Srpaulo#endif 3403190225Srpaulo default: 3404190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 3405190225Srpaulo "unsupported tpacket version %d", 3406190225Srpaulo handle->md.tp_version); 3407190225Srpaulo return -1; 3408190225Srpaulo } 3409190225Srpaulo /* perform sanity check on internal offset. */ 3410190225Srpaulo if (tp_mac + tp_snaplen > handle->bufsize) { 3411190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 3412190225Srpaulo "corrupted frame on kernel ring mac " 3413190225Srpaulo "offset %d + caplen %d > frame len %d", 3414190225Srpaulo tp_mac, tp_snaplen, handle->bufsize); 3415190225Srpaulo return -1; 3416190225Srpaulo } 3417190225Srpaulo 3418190225Srpaulo /* run filter on received packet 3419190225Srpaulo * If the kernel filtering is enabled we need to run the 3420190225Srpaulo * filter until all the frames present into the ring 3421190225Srpaulo * at filter creation time are processed. 3422190225Srpaulo * In such case md.use_bpf is used as a counter for the 3423190225Srpaulo * packet we need to filter. 3424190225Srpaulo * Note: alternatively it could be possible to stop applying 3425190225Srpaulo * the filter when the ring became empty, but it can possibly 3426190225Srpaulo * happen a lot later... */ 3427190225Srpaulo bp = (unsigned char*)h.raw + tp_mac; 3428190225Srpaulo run_bpf = (!handle->md.use_bpf) || 3429190225Srpaulo ((handle->md.use_bpf>1) && handle->md.use_bpf--); 3430190225Srpaulo if (run_bpf && handle->fcode.bf_insns && 3431190225Srpaulo (bpf_filter(handle->fcode.bf_insns, bp, 3432190225Srpaulo tp_len, tp_snaplen) == 0)) 3433190225Srpaulo goto skip; 3434190225Srpaulo 3435214518Srpaulo /* 3436214518Srpaulo * Do checks based on packet direction. 3437214518Srpaulo */ 3438190225Srpaulo sll = (void *)h.raw + TPACKET_ALIGN(handle->md.tp_hdrlen); 3439214518Srpaulo if (sll->sll_pkttype == PACKET_OUTGOING) { 3440214518Srpaulo /* 3441214518Srpaulo * Outgoing packet. 3442214518Srpaulo * If this is from the loopback device, reject it; 3443214518Srpaulo * we'll see the packet as an incoming packet as well, 3444214518Srpaulo * and we don't want to see it twice. 3445214518Srpaulo */ 3446214518Srpaulo if (sll->sll_ifindex == handle->md.lo_ifindex) 3447214518Srpaulo goto skip; 3448190225Srpaulo 3449214518Srpaulo /* 3450214518Srpaulo * If the user only wants incoming packets, reject it. 3451214518Srpaulo */ 3452214518Srpaulo if (handle->direction == PCAP_D_IN) 3453214518Srpaulo goto skip; 3454214518Srpaulo } else { 3455214518Srpaulo /* 3456214518Srpaulo * Incoming packet. 3457214518Srpaulo * If the user only wants outgoing packets, reject it. 3458214518Srpaulo */ 3459214518Srpaulo if (handle->direction == PCAP_D_OUT) 3460214518Srpaulo goto skip; 3461214518Srpaulo } 3462214518Srpaulo 3463190225Srpaulo /* get required packet info from ring header */ 3464190225Srpaulo pcaphdr.ts.tv_sec = tp_sec; 3465190225Srpaulo pcaphdr.ts.tv_usec = tp_usec; 3466190225Srpaulo pcaphdr.caplen = tp_snaplen; 3467190225Srpaulo pcaphdr.len = tp_len; 3468190225Srpaulo 3469190225Srpaulo /* if required build in place the sll header*/ 3470190225Srpaulo if (handle->md.cooked) { 3471190225Srpaulo struct sll_header *hdrp; 3472190225Srpaulo 3473190225Srpaulo /* 3474190225Srpaulo * The kernel should have left us with enough 3475190225Srpaulo * space for an sll header; back up the packet 3476190225Srpaulo * data pointer into that space, as that'll be 3477190225Srpaulo * the beginning of the packet we pass to the 3478190225Srpaulo * callback. 3479190225Srpaulo */ 3480190225Srpaulo bp -= SLL_HDR_LEN; 3481190225Srpaulo 3482190225Srpaulo /* 3483190225Srpaulo * Let's make sure that's past the end of 3484190225Srpaulo * the tpacket header, i.e. >= 3485190225Srpaulo * ((u_char *)thdr + TPACKET_HDRLEN), so we 3486190225Srpaulo * don't step on the header when we construct 3487190225Srpaulo * the sll header. 3488190225Srpaulo */ 3489190225Srpaulo if (bp < (u_char *)h.raw + 3490190225Srpaulo TPACKET_ALIGN(handle->md.tp_hdrlen) + 3491190225Srpaulo sizeof(struct sockaddr_ll)) { 3492190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 3493190225Srpaulo "cooked-mode frame doesn't have room for sll header"); 3494190225Srpaulo return -1; 3495190225Srpaulo } 3496190225Srpaulo 3497190225Srpaulo /* 3498190225Srpaulo * OK, that worked; construct the sll header. 3499190225Srpaulo */ 3500190225Srpaulo hdrp = (struct sll_header *)bp; 3501190225Srpaulo hdrp->sll_pkttype = map_packet_type_to_sll_type( 3502190225Srpaulo sll->sll_pkttype); 3503190225Srpaulo hdrp->sll_hatype = htons(sll->sll_hatype); 3504190225Srpaulo hdrp->sll_halen = htons(sll->sll_halen); 3505190225Srpaulo memcpy(hdrp->sll_addr, sll->sll_addr, SLL_ADDRLEN); 3506190225Srpaulo hdrp->sll_protocol = sll->sll_protocol; 3507190225Srpaulo 3508190225Srpaulo /* update packet len */ 3509190225Srpaulo pcaphdr.caplen += SLL_HDR_LEN; 3510190225Srpaulo pcaphdr.len += SLL_HDR_LEN; 3511190225Srpaulo } 3512190225Srpaulo 3513190225Srpaulo#ifdef HAVE_TPACKET2 3514190225Srpaulo if (handle->md.tp_version == TPACKET_V2 && h.h2->tp_vlan_tci && 3515190225Srpaulo tp_snaplen >= 2 * ETH_ALEN) { 3516190225Srpaulo struct vlan_tag *tag; 3517190225Srpaulo 3518190225Srpaulo bp -= VLAN_TAG_LEN; 3519190225Srpaulo memmove(bp, bp + VLAN_TAG_LEN, 2 * ETH_ALEN); 3520190225Srpaulo 3521190225Srpaulo tag = (struct vlan_tag *)(bp + 2 * ETH_ALEN); 3522190225Srpaulo tag->vlan_tpid = htons(ETH_P_8021Q); 3523190225Srpaulo tag->vlan_tci = htons(h.h2->tp_vlan_tci); 3524190225Srpaulo 3525190225Srpaulo pcaphdr.caplen += VLAN_TAG_LEN; 3526190225Srpaulo pcaphdr.len += VLAN_TAG_LEN; 3527190225Srpaulo } 3528190225Srpaulo#endif 3529190225Srpaulo 3530214518Srpaulo /* 3531214518Srpaulo * The only way to tell the kernel to cut off the 3532214518Srpaulo * packet at a snapshot length is with a filter program; 3533214518Srpaulo * if there's no filter program, the kernel won't cut 3534214518Srpaulo * the packet off. 3535214518Srpaulo * 3536214518Srpaulo * Trim the snapshot length to be no longer than the 3537214518Srpaulo * specified snapshot length. 3538214518Srpaulo */ 3539214518Srpaulo if (pcaphdr.caplen > handle->snapshot) 3540214518Srpaulo pcaphdr.caplen = handle->snapshot; 3541214518Srpaulo 3542190225Srpaulo /* pass the packet to the user */ 3543190225Srpaulo pkts++; 3544190225Srpaulo callback(user, &pcaphdr, bp); 3545190225Srpaulo handle->md.packets_read++; 3546190225Srpaulo 3547190225Srpauloskip: 3548190225Srpaulo /* next packet */ 3549190225Srpaulo switch (handle->md.tp_version) { 3550190225Srpaulo case TPACKET_V1: 3551190225Srpaulo h.h1->tp_status = TP_STATUS_KERNEL; 3552190225Srpaulo break; 3553190225Srpaulo#ifdef HAVE_TPACKET2 3554190225Srpaulo case TPACKET_V2: 3555190225Srpaulo h.h2->tp_status = TP_STATUS_KERNEL; 3556190225Srpaulo break; 3557190225Srpaulo#endif 3558190225Srpaulo } 3559190225Srpaulo if (++handle->offset >= handle->cc) 3560190225Srpaulo handle->offset = 0; 3561190225Srpaulo 3562190225Srpaulo /* check for break loop condition*/ 3563190225Srpaulo if (handle->break_loop) { 3564190225Srpaulo handle->break_loop = 0; 3565214518Srpaulo return PCAP_ERROR_BREAK; 3566190225Srpaulo } 3567190225Srpaulo } 3568190225Srpaulo return pkts; 3569190225Srpaulo} 3570190225Srpaulo 3571190225Srpaulostatic int 3572190225Srpaulopcap_setfilter_linux_mmap(pcap_t *handle, struct bpf_program *filter) 3573190225Srpaulo{ 3574190225Srpaulo int n, offset; 3575214518Srpaulo int ret; 3576214518Srpaulo 3577214518Srpaulo /* 3578214518Srpaulo * Don't rewrite "ret" instructions; we don't need to, as 3579214518Srpaulo * we're not reading packets with recvmsg(), and we don't 3580214518Srpaulo * want to, as, by not rewriting them, the kernel can avoid 3581214518Srpaulo * copying extra data. 3582214518Srpaulo */ 3583214518Srpaulo ret = pcap_setfilter_linux_common(handle, filter, 1); 3584190225Srpaulo if (ret < 0) 3585190225Srpaulo return ret; 3586190225Srpaulo 3587190225Srpaulo /* if the kernel filter is enabled, we need to apply the filter on 3588190225Srpaulo * all packets present into the ring. Get an upper bound of their number 3589190225Srpaulo */ 3590190225Srpaulo if (!handle->md.use_bpf) 3591190225Srpaulo return ret; 3592190225Srpaulo 3593190225Srpaulo /* walk the ring backward and count the free slot */ 3594190225Srpaulo offset = handle->offset; 3595190225Srpaulo if (--handle->offset < 0) 3596190225Srpaulo handle->offset = handle->cc - 1; 3597190225Srpaulo for (n=0; n < handle->cc; ++n) { 3598190225Srpaulo if (--handle->offset < 0) 3599190225Srpaulo handle->offset = handle->cc - 1; 3600190225Srpaulo if (!pcap_get_ring_frame(handle, TP_STATUS_KERNEL)) 3601190225Srpaulo break; 3602190225Srpaulo } 3603190225Srpaulo 3604190225Srpaulo /* be careful to not change current ring position */ 3605190225Srpaulo handle->offset = offset; 3606190225Srpaulo 3607190225Srpaulo /* store the number of packets currently present in the ring */ 3608190225Srpaulo handle->md.use_bpf = 1 + (handle->cc - n); 3609190225Srpaulo return ret; 3610190225Srpaulo} 3611190225Srpaulo 3612190225Srpaulo#endif /* HAVE_PACKET_RING */ 3613190225Srpaulo 3614190225Srpaulo 361575107Sfenner#ifdef HAVE_PF_PACKET_SOCKETS 361675107Sfenner/* 3617127664Sbms * Return the index of the given device name. Fill ebuf and return 361875107Sfenner * -1 on failure. 361975107Sfenner */ 362075107Sfennerstatic int 362175107Sfenneriface_get_id(int fd, const char *device, char *ebuf) 362275107Sfenner{ 362375107Sfenner struct ifreq ifr; 362426175Sfenner 362539291Sfenner memset(&ifr, 0, sizeof(ifr)); 362639291Sfenner strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); 362775107Sfenner 362875107Sfenner if (ioctl(fd, SIOCGIFINDEX, &ifr) == -1) { 362975107Sfenner snprintf(ebuf, PCAP_ERRBUF_SIZE, 3630172677Smlaier "SIOCGIFINDEX: %s", pcap_strerror(errno)); 363175107Sfenner return -1; 363226175Sfenner } 363326175Sfenner 363475107Sfenner return ifr.ifr_ifindex; 363575107Sfenner} 363626175Sfenner 363775107Sfenner/* 3638127664Sbms * Bind the socket associated with FD to the given device. 3639190225Srpaulo * Return 1 on success, 0 if we should try a SOCK_PACKET socket, 3640190225Srpaulo * or a PCAP_ERROR_ value on a hard error. 364175107Sfenner */ 364275107Sfennerstatic int 364375107Sfenneriface_bind(int fd, int ifindex, char *ebuf) 364475107Sfenner{ 364575107Sfenner struct sockaddr_ll sll; 3646127664Sbms int err; 3647127664Sbms socklen_t errlen = sizeof(err); 364875107Sfenner 364975107Sfenner memset(&sll, 0, sizeof(sll)); 365075107Sfenner sll.sll_family = AF_PACKET; 365175107Sfenner sll.sll_ifindex = ifindex; 365275107Sfenner sll.sll_protocol = htons(ETH_P_ALL); 365375107Sfenner 365475107Sfenner if (bind(fd, (struct sockaddr *) &sll, sizeof(sll)) == -1) { 3655190225Srpaulo if (errno == ENETDOWN) { 3656190225Srpaulo /* 3657190225Srpaulo * Return a "network down" indication, so that 3658190225Srpaulo * the application can report that rather than 3659190225Srpaulo * saying we had a mysterious failure and 3660190225Srpaulo * suggest that they report a problem to the 3661190225Srpaulo * libpcap developers. 3662190225Srpaulo */ 3663190225Srpaulo return PCAP_ERROR_IFACE_NOT_UP; 3664190225Srpaulo } else { 3665190225Srpaulo snprintf(ebuf, PCAP_ERRBUF_SIZE, 3666190225Srpaulo "bind: %s", pcap_strerror(errno)); 3667190225Srpaulo return PCAP_ERROR; 3668190225Srpaulo } 366926175Sfenner } 367026175Sfenner 3671127664Sbms /* Any pending errors, e.g., network is down? */ 3672127664Sbms 3673127664Sbms if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &errlen) == -1) { 3674127664Sbms snprintf(ebuf, PCAP_ERRBUF_SIZE, 3675127664Sbms "getsockopt: %s", pcap_strerror(errno)); 3676190225Srpaulo return 0; 3677127664Sbms } 3678127664Sbms 3679190225Srpaulo if (err == ENETDOWN) { 3680190225Srpaulo /* 3681190225Srpaulo * Return a "network down" indication, so that 3682190225Srpaulo * the application can report that rather than 3683190225Srpaulo * saying we had a mysterious failure and 3684190225Srpaulo * suggest that they report a problem to the 3685190225Srpaulo * libpcap developers. 3686190225Srpaulo */ 3687190225Srpaulo return PCAP_ERROR_IFACE_NOT_UP; 3688190225Srpaulo } else if (err > 0) { 3689127664Sbms snprintf(ebuf, PCAP_ERRBUF_SIZE, 3690127664Sbms "bind: %s", pcap_strerror(err)); 3691190225Srpaulo return 0; 3692127664Sbms } 3693127664Sbms 3694190225Srpaulo return 1; 369575107Sfenner} 369675107Sfenner 3697214518Srpaulo#ifdef IW_MODE_MONITOR 369875107Sfenner/* 3699190225Srpaulo * Check whether the device supports the Wireless Extensions. 3700190225Srpaulo * Returns 1 if it does, 0 if it doesn't, PCAP_ERROR_NO_SUCH_DEVICE 3701190225Srpaulo * if the device doesn't even exist. 370275107Sfenner */ 3703190225Srpaulostatic int 3704190225Srpaulohas_wext(int sock_fd, const char *device, char *ebuf) 3705190225Srpaulo{ 3706190225Srpaulo struct iwreq ireq; 370775107Sfenner 3708190225Srpaulo strncpy(ireq.ifr_ifrn.ifrn_name, device, 3709190225Srpaulo sizeof ireq.ifr_ifrn.ifrn_name); 3710190225Srpaulo ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0; 3711190225Srpaulo if (ioctl(sock_fd, SIOCGIWNAME, &ireq) >= 0) 3712190225Srpaulo return 1; /* yes */ 3713190225Srpaulo snprintf(ebuf, PCAP_ERRBUF_SIZE, 3714190225Srpaulo "%s: SIOCGIWPRIV: %s", device, pcap_strerror(errno)); 3715190225Srpaulo if (errno == ENODEV) 3716190225Srpaulo return PCAP_ERROR_NO_SUCH_DEVICE; 3717190225Srpaulo return 0; 3718190225Srpaulo} 3719190225Srpaulo 372075107Sfenner/* 3721190225Srpaulo * Per me si va ne la citta dolente, 3722190225Srpaulo * Per me si va ne l'etterno dolore, 3723190225Srpaulo * ... 3724190225Srpaulo * Lasciate ogne speranza, voi ch'intrate. 3725190225Srpaulo * 3726190225Srpaulo * XXX - airmon-ng does special stuff with the Orinoco driver and the 3727190225Srpaulo * wlan-ng driver. 372875107Sfenner */ 3729190225Srpaulotypedef enum { 3730190225Srpaulo MONITOR_WEXT, 3731190225Srpaulo MONITOR_HOSTAP, 3732190225Srpaulo MONITOR_PRISM, 3733190225Srpaulo MONITOR_PRISM54, 3734190225Srpaulo MONITOR_ACX100, 3735190225Srpaulo MONITOR_RT2500, 3736190225Srpaulo MONITOR_RT2570, 3737190225Srpaulo MONITOR_RT73, 3738190225Srpaulo MONITOR_RTL8XXX 3739190225Srpaulo} monitor_type; 374075107Sfenner 374175107Sfenner/* 3742190225Srpaulo * Use the Wireless Extensions, if we have them, to try to turn monitor mode 3743190225Srpaulo * on if it's not already on. 3744190225Srpaulo * 3745190225Srpaulo * Returns 1 on success, 0 if we don't support the Wireless Extensions 3746190225Srpaulo * on this device, or a PCAP_ERROR_ value if we do support them but 3747190225Srpaulo * we weren't able to turn monitor mode on. 374875107Sfenner */ 3749190225Srpaulostatic int 3750190225Srpauloenter_rfmon_mode_wext(pcap_t *handle, int sock_fd, const char *device) 375175107Sfenner{ 3752190225Srpaulo /* 3753190225Srpaulo * XXX - at least some adapters require non-Wireless Extensions 3754190225Srpaulo * mechanisms to turn monitor mode on. 3755190225Srpaulo * 3756190225Srpaulo * Atheros cards might require that a separate "monitor virtual access 3757190225Srpaulo * point" be created, with later versions of the madwifi driver. 3758190225Srpaulo * airmon-ng does "wlanconfig ath create wlandev {if} wlanmode 3759190225Srpaulo * monitor -bssid", which apparently spits out a line "athN" 3760190225Srpaulo * where "athN" is the monitor mode device. To leave monitor 3761190225Srpaulo * mode, it destroys the monitor mode device. 3762190225Srpaulo * 3763190225Srpaulo * Some Intel Centrino adapters might require private ioctls to get 3764190225Srpaulo * radio headers; the ipw2200 and ipw3945 drivers allow you to 3765190225Srpaulo * configure a separate "rtapN" interface to capture in monitor 3766190225Srpaulo * mode without preventing the adapter from operating normally. 3767190225Srpaulo * (airmon-ng doesn't appear to use that, though.) 3768190225Srpaulo * 3769190225Srpaulo * It would be Truly Wonderful if mac80211 and nl80211 cleaned this 3770190225Srpaulo * up, and if all drivers were converted to mac80211 drivers. 3771190225Srpaulo * 3772190225Srpaulo * If interface {if} is a mac80211 driver, the file 3773190225Srpaulo * /sys/class/net/{if}/phy80211 is a symlink to 3774190225Srpaulo * /sys/class/ieee80211/{phydev}, for some {phydev}. 3775190225Srpaulo * 3776190225Srpaulo * On Fedora 9, with a 2.6.26.3-29 kernel, my Zydas stick, at 3777190225Srpaulo * least, has a "wmaster0" device and a "wlan0" device; the 3778190225Srpaulo * latter is the one with the IP address. Both show up in 3779190225Srpaulo * "tcpdump -D" output. Capturing on the wmaster0 device 3780190225Srpaulo * captures with 802.11 headers. 3781190225Srpaulo * 3782190225Srpaulo * airmon-ng searches through /sys/class/net for devices named 3783190225Srpaulo * monN, starting with mon0; as soon as one *doesn't* exist, 3784190225Srpaulo * it chooses that as the monitor device name. If the "iw" 3785190225Srpaulo * command exists, it does "iw dev {if} interface add {monif} 3786190225Srpaulo * type monitor", where {monif} is the monitor device. It 3787190225Srpaulo * then (sigh) sleeps .1 second, and then configures the 3788190225Srpaulo * device up. Otherwise, if /sys/class/ieee80211/{phydev}/add_iface 3789190225Srpaulo * is a file, it writes {mondev}, without a newline, to that file, 3790190225Srpaulo * and again (sigh) sleeps .1 second, and then iwconfig's that 3791190225Srpaulo * device into monitor mode and configures it up. Otherwise, 3792190225Srpaulo * you can't do monitor mode. 3793190225Srpaulo * 3794190225Srpaulo * All these devices are "glued" together by having the 3795190225Srpaulo * /sys/class/net/{device}/phy80211 links pointing to the same 3796190225Srpaulo * place, so, given a wmaster, wlan, or mon device, you can 3797190225Srpaulo * find the other devices by looking for devices with 3798190225Srpaulo * the same phy80211 link. 3799190225Srpaulo * 3800190225Srpaulo * To turn monitor mode off, delete the monitor interface, 3801190225Srpaulo * either with "iw dev {monif} interface del" or by sending 3802190225Srpaulo * {monif}, with no NL, down /sys/class/ieee80211/{phydev}/remove_iface 3803190225Srpaulo * 3804190225Srpaulo * Note: if you try to create a monitor device named "monN", and 3805190225Srpaulo * there's already a "monN" device, it fails, as least with 3806190225Srpaulo * the netlink interface (which is what iw uses), with a return 3807190225Srpaulo * value of -ENFILE. (Return values are negative errnos.) We 3808190225Srpaulo * could probably use that to find an unused device. 3809190225Srpaulo */ 3810190225Srpaulo int err; 3811190225Srpaulo struct iwreq ireq; 3812190225Srpaulo struct iw_priv_args *priv; 3813190225Srpaulo monitor_type montype; 3814190225Srpaulo int i; 3815190225Srpaulo __u32 cmd; 3816190225Srpaulo int args[2]; 3817190225Srpaulo int channel; 381875107Sfenner 3819190225Srpaulo /* 3820190225Srpaulo * Does this device *support* the Wireless Extensions? 3821190225Srpaulo */ 3822190225Srpaulo err = has_wext(sock_fd, device, handle->errbuf); 3823190225Srpaulo if (err <= 0) 3824190225Srpaulo return err; /* either it doesn't or the device doesn't even exist */ 3825190225Srpaulo /* 3826190225Srpaulo * Try to get all the Wireless Extensions private ioctls 3827190225Srpaulo * supported by this device. 3828190225Srpaulo * 3829190225Srpaulo * First, get the size of the buffer we need, by supplying no 3830190225Srpaulo * buffer and a length of 0. If the device supports private 3831190225Srpaulo * ioctls, it should return E2BIG, with ireq.u.data.length set 3832190225Srpaulo * to the length we need. If it doesn't support them, it should 3833190225Srpaulo * return EOPNOTSUPP. 3834190225Srpaulo */ 3835190225Srpaulo memset(&ireq, 0, sizeof ireq); 3836190225Srpaulo strncpy(ireq.ifr_ifrn.ifrn_name, device, 3837190225Srpaulo sizeof ireq.ifr_ifrn.ifrn_name); 3838190225Srpaulo ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0; 3839214518Srpaulo ireq.u.data.pointer = (void *)args; 3840190225Srpaulo ireq.u.data.length = 0; 3841190225Srpaulo ireq.u.data.flags = 0; 3842190225Srpaulo if (ioctl(sock_fd, SIOCGIWPRIV, &ireq) != -1) { 3843190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 3844190225Srpaulo "%s: SIOCGIWPRIV with a zero-length buffer didn't fail!", 3845190225Srpaulo device); 3846190225Srpaulo return PCAP_ERROR; 3847190225Srpaulo } 3848190225Srpaulo if (errno == EOPNOTSUPP) { 3849190225Srpaulo /* 3850190225Srpaulo * No private ioctls, so we assume that there's only one 3851190225Srpaulo * DLT_ for monitor mode. 3852190225Srpaulo */ 3853190225Srpaulo return 0; 3854190225Srpaulo } 3855190225Srpaulo if (errno != E2BIG) { 3856190225Srpaulo /* 3857190225Srpaulo * Failed. 3858190225Srpaulo */ 3859190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 3860190225Srpaulo "%s: SIOCGIWPRIV: %s", device, pcap_strerror(errno)); 3861190225Srpaulo return PCAP_ERROR; 3862190225Srpaulo } 3863190225Srpaulo priv = malloc(ireq.u.data.length * sizeof (struct iw_priv_args)); 3864190225Srpaulo if (priv == NULL) { 3865190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 3866190225Srpaulo "malloc: %s", pcap_strerror(errno)); 3867190225Srpaulo return PCAP_ERROR; 3868190225Srpaulo } 3869214518Srpaulo ireq.u.data.pointer = (void *)priv; 3870190225Srpaulo if (ioctl(sock_fd, SIOCGIWPRIV, &ireq) == -1) { 3871190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 3872190225Srpaulo "%s: SIOCGIWPRIV: %s", device, pcap_strerror(errno)); 3873190225Srpaulo free(priv); 3874190225Srpaulo return PCAP_ERROR; 3875190225Srpaulo } 387675107Sfenner 3877190225Srpaulo /* 3878190225Srpaulo * Look for private ioctls to turn monitor mode on or, if 3879190225Srpaulo * monitor mode is on, to set the header type. 3880190225Srpaulo */ 3881190225Srpaulo montype = MONITOR_WEXT; 3882190225Srpaulo cmd = 0; 3883190225Srpaulo for (i = 0; i < ireq.u.data.length; i++) { 3884190225Srpaulo if (strcmp(priv[i].name, "monitor_type") == 0) { 3885190225Srpaulo /* 3886190225Srpaulo * Hostap driver, use this one. 3887190225Srpaulo * Set monitor mode first. 3888190225Srpaulo * You can set it to 0 to get DLT_IEEE80211, 3889214518Srpaulo * 1 to get DLT_PRISM, 2 to get 3890214518Srpaulo * DLT_IEEE80211_RADIO_AVS, and, with more 3891214518Srpaulo * recent versions of the driver, 3 to get 3892214518Srpaulo * DLT_IEEE80211_RADIO. 3893190225Srpaulo */ 3894190225Srpaulo if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT) 3895190225Srpaulo break; 3896190225Srpaulo if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED)) 3897190225Srpaulo break; 3898190225Srpaulo if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1) 3899190225Srpaulo break; 3900190225Srpaulo montype = MONITOR_HOSTAP; 3901190225Srpaulo cmd = priv[i].cmd; 3902190225Srpaulo break; 3903190225Srpaulo } 3904190225Srpaulo if (strcmp(priv[i].name, "set_prismhdr") == 0) { 3905190225Srpaulo /* 3906190225Srpaulo * Prism54 driver, use this one. 3907190225Srpaulo * Set monitor mode first. 3908190225Srpaulo * You can set it to 2 to get DLT_IEEE80211 3909190225Srpaulo * or 3 or get DLT_PRISM. 3910190225Srpaulo */ 3911190225Srpaulo if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT) 3912190225Srpaulo break; 3913190225Srpaulo if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED)) 3914190225Srpaulo break; 3915190225Srpaulo if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1) 3916190225Srpaulo break; 3917190225Srpaulo montype = MONITOR_PRISM54; 3918190225Srpaulo cmd = priv[i].cmd; 3919190225Srpaulo break; 3920190225Srpaulo } 3921190225Srpaulo if (strcmp(priv[i].name, "forceprismheader") == 0) { 3922190225Srpaulo /* 3923190225Srpaulo * RT2570 driver, use this one. 3924190225Srpaulo * Do this after turning monitor mode on. 3925190225Srpaulo * You can set it to 1 to get DLT_PRISM or 2 3926190225Srpaulo * to get DLT_IEEE80211. 3927190225Srpaulo */ 3928190225Srpaulo if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT) 3929190225Srpaulo break; 3930190225Srpaulo if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED)) 3931190225Srpaulo break; 3932190225Srpaulo if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1) 3933190225Srpaulo break; 3934190225Srpaulo montype = MONITOR_RT2570; 3935190225Srpaulo cmd = priv[i].cmd; 3936190225Srpaulo break; 3937190225Srpaulo } 3938190225Srpaulo if (strcmp(priv[i].name, "forceprism") == 0) { 3939190225Srpaulo /* 3940190225Srpaulo * RT73 driver, use this one. 3941190225Srpaulo * Do this after turning monitor mode on. 3942190225Srpaulo * Its argument is a *string*; you can 3943190225Srpaulo * set it to "1" to get DLT_PRISM or "2" 3944190225Srpaulo * to get DLT_IEEE80211. 3945190225Srpaulo */ 3946190225Srpaulo if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_CHAR) 3947190225Srpaulo break; 3948190225Srpaulo if (priv[i].set_args & IW_PRIV_SIZE_FIXED) 3949190225Srpaulo break; 3950190225Srpaulo montype = MONITOR_RT73; 3951190225Srpaulo cmd = priv[i].cmd; 3952190225Srpaulo break; 3953190225Srpaulo } 3954190225Srpaulo if (strcmp(priv[i].name, "prismhdr") == 0) { 3955190225Srpaulo /* 3956190225Srpaulo * One of the RTL8xxx drivers, use this one. 3957190225Srpaulo * It can only be done after monitor mode 3958190225Srpaulo * has been turned on. You can set it to 1 3959190225Srpaulo * to get DLT_PRISM or 0 to get DLT_IEEE80211. 3960190225Srpaulo */ 3961190225Srpaulo if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT) 3962190225Srpaulo break; 3963190225Srpaulo if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED)) 3964190225Srpaulo break; 3965190225Srpaulo if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1) 3966190225Srpaulo break; 3967190225Srpaulo montype = MONITOR_RTL8XXX; 3968190225Srpaulo cmd = priv[i].cmd; 3969190225Srpaulo break; 3970190225Srpaulo } 3971190225Srpaulo if (strcmp(priv[i].name, "rfmontx") == 0) { 3972190225Srpaulo /* 3973190225Srpaulo * RT2500 or RT61 driver, use this one. 3974190225Srpaulo * It has one one-byte parameter; set 3975190225Srpaulo * u.data.length to 1 and u.data.pointer to 3976190225Srpaulo * point to the parameter. 3977190225Srpaulo * It doesn't itself turn monitor mode on. 3978190225Srpaulo * You can set it to 1 to allow transmitting 3979190225Srpaulo * in monitor mode(?) and get DLT_IEEE80211, 3980190225Srpaulo * or set it to 0 to disallow transmitting in 3981190225Srpaulo * monitor mode(?) and get DLT_PRISM. 3982190225Srpaulo */ 3983190225Srpaulo if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT) 3984190225Srpaulo break; 3985190225Srpaulo if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 2) 3986190225Srpaulo break; 3987190225Srpaulo montype = MONITOR_RT2500; 3988190225Srpaulo cmd = priv[i].cmd; 3989190225Srpaulo break; 3990190225Srpaulo } 3991190225Srpaulo if (strcmp(priv[i].name, "monitor") == 0) { 3992190225Srpaulo /* 3993190225Srpaulo * Either ACX100 or hostap, use this one. 3994190225Srpaulo * It turns monitor mode on. 3995190225Srpaulo * If it takes two arguments, it's ACX100; 3996190225Srpaulo * the first argument is 1 for DLT_PRISM 3997190225Srpaulo * or 2 for DLT_IEEE80211, and the second 3998190225Srpaulo * argument is the channel on which to 3999190225Srpaulo * run. If it takes one argument, it's 4000190225Srpaulo * HostAP, and the argument is 2 for 4001190225Srpaulo * DLT_IEEE80211 and 3 for DLT_PRISM. 4002190225Srpaulo * 4003190225Srpaulo * If we see this, we don't quit, as this 4004190225Srpaulo * might be a version of the hostap driver 4005190225Srpaulo * that also supports "monitor_type". 4006190225Srpaulo */ 4007190225Srpaulo if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT) 4008190225Srpaulo break; 4009190225Srpaulo if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED)) 4010190225Srpaulo break; 4011190225Srpaulo switch (priv[i].set_args & IW_PRIV_SIZE_MASK) { 401275107Sfenner 4013190225Srpaulo case 1: 4014190225Srpaulo montype = MONITOR_PRISM; 4015190225Srpaulo cmd = priv[i].cmd; 4016190225Srpaulo break; 4017190225Srpaulo 4018190225Srpaulo case 2: 4019190225Srpaulo montype = MONITOR_ACX100; 4020190225Srpaulo cmd = priv[i].cmd; 4021190225Srpaulo break; 4022190225Srpaulo 4023190225Srpaulo default: 4024190225Srpaulo break; 4025190225Srpaulo } 4026190225Srpaulo } 4027190225Srpaulo } 4028190225Srpaulo free(priv); 4029190225Srpaulo 4030190225Srpaulo /* 4031190225Srpaulo * XXX - ipw3945? islism? 4032190225Srpaulo */ 4033190225Srpaulo 4034190225Srpaulo /* 4035190225Srpaulo * Get the old mode. 4036190225Srpaulo */ 4037190225Srpaulo strncpy(ireq.ifr_ifrn.ifrn_name, device, 4038190225Srpaulo sizeof ireq.ifr_ifrn.ifrn_name); 4039190225Srpaulo ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0; 4040190225Srpaulo if (ioctl(sock_fd, SIOCGIWMODE, &ireq) == -1) { 404175107Sfenner /* 4042190225Srpaulo * We probably won't be able to set the mode, either. 4043190225Srpaulo */ 4044190225Srpaulo return PCAP_ERROR_RFMON_NOTSUP; 4045190225Srpaulo } 4046190225Srpaulo 4047190225Srpaulo /* 4048190225Srpaulo * Is it currently in monitor mode? 4049190225Srpaulo */ 4050190225Srpaulo if (ireq.u.mode == IW_MODE_MONITOR) { 4051190225Srpaulo /* 4052190225Srpaulo * Yes. Just leave things as they are. 4053190225Srpaulo * We don't offer multiple link-layer types, as 4054190225Srpaulo * changing the link-layer type out from under 4055190225Srpaulo * somebody else capturing in monitor mode would 4056190225Srpaulo * be considered rude. 4057190225Srpaulo */ 4058190225Srpaulo return 1; 4059190225Srpaulo } 4060190225Srpaulo /* 4061190225Srpaulo * No. We have to put the adapter into rfmon mode. 4062190225Srpaulo */ 4063190225Srpaulo 4064190225Srpaulo /* 4065190225Srpaulo * If we haven't already done so, arrange to have 4066190225Srpaulo * "pcap_close_all()" called when we exit. 4067190225Srpaulo */ 4068190225Srpaulo if (!pcap_do_addexit(handle)) { 4069190225Srpaulo /* 4070190225Srpaulo * "atexit()" failed; don't put the interface 4071190225Srpaulo * in rfmon mode, just give up. 4072190225Srpaulo */ 4073190225Srpaulo return PCAP_ERROR_RFMON_NOTSUP; 4074190225Srpaulo } 4075190225Srpaulo 4076190225Srpaulo /* 4077190225Srpaulo * Save the old mode. 4078190225Srpaulo */ 4079190225Srpaulo handle->md.oldmode = ireq.u.mode; 4080190225Srpaulo 4081190225Srpaulo /* 4082190225Srpaulo * Put the adapter in rfmon mode. How we do this depends 4083190225Srpaulo * on whether we have a special private ioctl or not. 4084190225Srpaulo */ 4085190225Srpaulo if (montype == MONITOR_PRISM) { 4086190225Srpaulo /* 4087190225Srpaulo * We have the "monitor" private ioctl, but none of 4088190225Srpaulo * the other private ioctls. Use this, and select 4089190225Srpaulo * the Prism header. 409075107Sfenner * 4091190225Srpaulo * If it fails, just fall back on SIOCSIWMODE. 409275107Sfenner */ 4093190225Srpaulo memset(&ireq, 0, sizeof ireq); 4094190225Srpaulo strncpy(ireq.ifr_ifrn.ifrn_name, device, 4095190225Srpaulo sizeof ireq.ifr_ifrn.ifrn_name); 4096190225Srpaulo ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0; 4097190225Srpaulo ireq.u.data.length = 1; /* 1 argument */ 4098190225Srpaulo args[0] = 3; /* request Prism header */ 4099190225Srpaulo memcpy(ireq.u.name, args, IFNAMSIZ); 4100190225Srpaulo if (ioctl(sock_fd, cmd, &ireq) != -1) { 4101190225Srpaulo /* 4102190225Srpaulo * Success. 4103190225Srpaulo * Note that we have to put the old mode back 4104190225Srpaulo * when we close the device. 4105190225Srpaulo */ 4106214518Srpaulo handle->md.must_do_on_close |= MUST_CLEAR_RFMON; 4107190225Srpaulo 4108190225Srpaulo /* 4109190225Srpaulo * Add this to the list of pcaps to close 4110190225Srpaulo * when we exit. 4111190225Srpaulo */ 4112190225Srpaulo pcap_add_to_pcaps_to_close(handle); 4113190225Srpaulo 4114190225Srpaulo return 1; 411526175Sfenner } 411675107Sfenner 411775107Sfenner /* 4118190225Srpaulo * Failure. Fall back on SIOCSIWMODE. 411975107Sfenner */ 4120190225Srpaulo } 4121190225Srpaulo 4122190225Srpaulo /* 4123190225Srpaulo * First, turn monitor mode on. 4124190225Srpaulo */ 4125190225Srpaulo strncpy(ireq.ifr_ifrn.ifrn_name, device, 4126190225Srpaulo sizeof ireq.ifr_ifrn.ifrn_name); 4127190225Srpaulo ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0; 4128190225Srpaulo ireq.u.mode = IW_MODE_MONITOR; 4129190225Srpaulo if (ioctl(sock_fd, SIOCSIWMODE, &ireq) == -1) { 4130190225Srpaulo /* 4131190225Srpaulo * Scientist, you've failed. 4132190225Srpaulo */ 4133190225Srpaulo return PCAP_ERROR_RFMON_NOTSUP; 4134190225Srpaulo } 4135190225Srpaulo 4136190225Srpaulo /* 4137190225Srpaulo * XXX - airmon-ng does "iwconfig {if} key off" after setting 4138190225Srpaulo * monitor mode and setting the channel, and then does 4139190225Srpaulo * "iwconfig up". 4140190225Srpaulo */ 4141190225Srpaulo 4142190225Srpaulo /* 4143190225Srpaulo * Now select the appropriate radio header. 4144190225Srpaulo */ 4145190225Srpaulo switch (montype) { 4146190225Srpaulo 4147190225Srpaulo case MONITOR_WEXT: 4148190225Srpaulo /* 4149190225Srpaulo * We don't have any private ioctl to set the header. 4150190225Srpaulo */ 4151190225Srpaulo break; 4152190225Srpaulo 4153190225Srpaulo case MONITOR_HOSTAP: 4154190225Srpaulo /* 4155214518Srpaulo * Try to select the radiotap header. 4156190225Srpaulo */ 4157190225Srpaulo memset(&ireq, 0, sizeof ireq); 4158190225Srpaulo strncpy(ireq.ifr_ifrn.ifrn_name, device, 4159190225Srpaulo sizeof ireq.ifr_ifrn.ifrn_name); 4160190225Srpaulo ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0; 4161214518Srpaulo args[0] = 3; /* request radiotap header */ 4162214518Srpaulo memcpy(ireq.u.name, args, sizeof (int)); 4163214518Srpaulo if (ioctl(sock_fd, cmd, &ireq) != -1) 4164214518Srpaulo break; /* success */ 4165214518Srpaulo 4166214518Srpaulo /* 4167214518Srpaulo * That failed. Try to select the AVS header. 4168214518Srpaulo */ 4169214518Srpaulo memset(&ireq, 0, sizeof ireq); 4170214518Srpaulo strncpy(ireq.ifr_ifrn.ifrn_name, device, 4171214518Srpaulo sizeof ireq.ifr_ifrn.ifrn_name); 4172214518Srpaulo ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0; 4173190225Srpaulo args[0] = 2; /* request AVS header */ 4174190225Srpaulo memcpy(ireq.u.name, args, sizeof (int)); 4175214518Srpaulo if (ioctl(sock_fd, cmd, &ireq) != -1) 4176214518Srpaulo break; /* success */ 4177214518Srpaulo 4178214518Srpaulo /* 4179214518Srpaulo * That failed. Try to select the Prism header. 4180214518Srpaulo */ 4181214518Srpaulo memset(&ireq, 0, sizeof ireq); 4182214518Srpaulo strncpy(ireq.ifr_ifrn.ifrn_name, device, 4183214518Srpaulo sizeof ireq.ifr_ifrn.ifrn_name); 4184214518Srpaulo ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0; 4185214518Srpaulo args[0] = 1; /* request Prism header */ 4186214518Srpaulo memcpy(ireq.u.name, args, sizeof (int)); 4187214518Srpaulo ioctl(sock_fd, cmd, &ireq); 4188190225Srpaulo break; 4189190225Srpaulo 4190190225Srpaulo case MONITOR_PRISM: 4191190225Srpaulo /* 4192190225Srpaulo * The private ioctl failed. 4193190225Srpaulo */ 4194190225Srpaulo break; 4195190225Srpaulo 4196190225Srpaulo case MONITOR_PRISM54: 4197190225Srpaulo /* 4198190225Srpaulo * Select the Prism header. 4199190225Srpaulo */ 4200190225Srpaulo memset(&ireq, 0, sizeof ireq); 4201190225Srpaulo strncpy(ireq.ifr_ifrn.ifrn_name, device, 4202190225Srpaulo sizeof ireq.ifr_ifrn.ifrn_name); 4203190225Srpaulo ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0; 4204190225Srpaulo args[0] = 3; /* request Prism header */ 4205190225Srpaulo memcpy(ireq.u.name, args, sizeof (int)); 4206190225Srpaulo ioctl(sock_fd, cmd, &ireq); 4207190225Srpaulo break; 4208190225Srpaulo 4209190225Srpaulo case MONITOR_ACX100: 4210190225Srpaulo /* 4211190225Srpaulo * Get the current channel. 4212190225Srpaulo */ 4213190225Srpaulo memset(&ireq, 0, sizeof ireq); 4214190225Srpaulo strncpy(ireq.ifr_ifrn.ifrn_name, device, 4215190225Srpaulo sizeof ireq.ifr_ifrn.ifrn_name); 4216190225Srpaulo ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0; 4217190225Srpaulo if (ioctl(sock_fd, SIOCGIWFREQ, &ireq) == -1) { 4218190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 4219190225Srpaulo "%s: SIOCGIWFREQ: %s", device, 4220190225Srpaulo pcap_strerror(errno)); 4221190225Srpaulo return PCAP_ERROR; 4222190225Srpaulo } 4223190225Srpaulo channel = ireq.u.freq.m; 4224190225Srpaulo 4225190225Srpaulo /* 4226190225Srpaulo * Select the Prism header, and set the channel to the 4227190225Srpaulo * current value. 4228190225Srpaulo */ 4229190225Srpaulo memset(&ireq, 0, sizeof ireq); 4230190225Srpaulo strncpy(ireq.ifr_ifrn.ifrn_name, device, 4231190225Srpaulo sizeof ireq.ifr_ifrn.ifrn_name); 4232190225Srpaulo ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0; 4233190225Srpaulo args[0] = 1; /* request Prism header */ 4234190225Srpaulo args[1] = channel; /* set channel */ 4235190225Srpaulo memcpy(ireq.u.name, args, 2*sizeof (int)); 4236190225Srpaulo ioctl(sock_fd, cmd, &ireq); 4237190225Srpaulo break; 4238190225Srpaulo 4239190225Srpaulo case MONITOR_RT2500: 4240190225Srpaulo /* 4241190225Srpaulo * Disallow transmission - that turns on the 4242190225Srpaulo * Prism header. 4243190225Srpaulo */ 4244190225Srpaulo memset(&ireq, 0, sizeof ireq); 4245190225Srpaulo strncpy(ireq.ifr_ifrn.ifrn_name, device, 4246190225Srpaulo sizeof ireq.ifr_ifrn.ifrn_name); 4247190225Srpaulo ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0; 4248190225Srpaulo args[0] = 0; /* disallow transmitting */ 4249190225Srpaulo memcpy(ireq.u.name, args, sizeof (int)); 4250190225Srpaulo ioctl(sock_fd, cmd, &ireq); 4251190225Srpaulo break; 4252190225Srpaulo 4253190225Srpaulo case MONITOR_RT2570: 4254190225Srpaulo /* 4255190225Srpaulo * Force the Prism header. 4256190225Srpaulo */ 4257190225Srpaulo memset(&ireq, 0, sizeof ireq); 4258190225Srpaulo strncpy(ireq.ifr_ifrn.ifrn_name, device, 4259190225Srpaulo sizeof ireq.ifr_ifrn.ifrn_name); 4260190225Srpaulo ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0; 4261190225Srpaulo args[0] = 1; /* request Prism header */ 4262190225Srpaulo memcpy(ireq.u.name, args, sizeof (int)); 4263190225Srpaulo ioctl(sock_fd, cmd, &ireq); 4264190225Srpaulo break; 4265190225Srpaulo 4266190225Srpaulo case MONITOR_RT73: 4267190225Srpaulo /* 4268190225Srpaulo * Force the Prism header. 4269190225Srpaulo */ 4270190225Srpaulo memset(&ireq, 0, sizeof ireq); 4271190225Srpaulo strncpy(ireq.ifr_ifrn.ifrn_name, device, 4272190225Srpaulo sizeof ireq.ifr_ifrn.ifrn_name); 4273190225Srpaulo ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0; 4274190225Srpaulo ireq.u.data.length = 1; /* 1 argument */ 4275190225Srpaulo ireq.u.data.pointer = "1"; 4276190225Srpaulo ireq.u.data.flags = 0; 4277190225Srpaulo ioctl(sock_fd, cmd, &ireq); 4278190225Srpaulo break; 4279190225Srpaulo 4280190225Srpaulo case MONITOR_RTL8XXX: 4281190225Srpaulo /* 4282190225Srpaulo * Force the Prism header. 4283190225Srpaulo */ 4284190225Srpaulo memset(&ireq, 0, sizeof ireq); 4285190225Srpaulo strncpy(ireq.ifr_ifrn.ifrn_name, device, 4286190225Srpaulo sizeof ireq.ifr_ifrn.ifrn_name); 4287190225Srpaulo ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0; 4288190225Srpaulo args[0] = 1; /* request Prism header */ 4289190225Srpaulo memcpy(ireq.u.name, args, sizeof (int)); 4290190225Srpaulo ioctl(sock_fd, cmd, &ireq); 4291190225Srpaulo break; 429226175Sfenner } 4293127664Sbms 4294190225Srpaulo /* 4295190225Srpaulo * Note that we have to put the old mode back when we 4296190225Srpaulo * close the device. 4297190225Srpaulo */ 4298214518Srpaulo handle->md.must_do_on_close |= MUST_CLEAR_RFMON; 4299190225Srpaulo 4300190225Srpaulo /* 4301190225Srpaulo * Add this to the list of pcaps to close when we exit. 4302190225Srpaulo */ 4303190225Srpaulo pcap_add_to_pcaps_to_close(handle); 4304190225Srpaulo 4305190225Srpaulo return 1; 4306214518Srpaulo} 4307214518Srpaulo#endif /* IW_MODE_MONITOR */ 4308214518Srpaulo 4309214518Srpaulo/* 4310214518Srpaulo * Try various mechanisms to enter monitor mode. 4311214518Srpaulo */ 4312214518Srpaulostatic int 4313214518Srpauloenter_rfmon_mode(pcap_t *handle, int sock_fd, const char *device) 4314214518Srpaulo{ 4315214518Srpaulo#if defined(HAVE_LIBNL) || defined(IW_MODE_MONITOR) 4316214518Srpaulo int ret; 4317214518Srpaulo#endif 4318214518Srpaulo 4319214518Srpaulo#ifdef HAVE_LIBNL 4320214518Srpaulo ret = enter_rfmon_mode_mac80211(handle, sock_fd, device); 4321214518Srpaulo if (ret < 0) 4322214518Srpaulo return ret; /* error attempting to do so */ 4323214518Srpaulo if (ret == 1) 4324214518Srpaulo return 1; /* success */ 4325214518Srpaulo#endif /* HAVE_LIBNL */ 4326214518Srpaulo 4327214518Srpaulo#ifdef IW_MODE_MONITOR 4328214518Srpaulo ret = enter_rfmon_mode_wext(handle, sock_fd, device); 4329214518Srpaulo if (ret < 0) 4330214518Srpaulo return ret; /* error attempting to do so */ 4331214518Srpaulo if (ret == 1) 4332214518Srpaulo return 1; /* success */ 4333214518Srpaulo#endif /* IW_MODE_MONITOR */ 4334214518Srpaulo 4335190225Srpaulo /* 4336214518Srpaulo * Either none of the mechanisms we know about work or none 4337214518Srpaulo * of those mechanisms are available, so we can't do monitor 4338214518Srpaulo * mode. 4339190225Srpaulo */ 4340190225Srpaulo return 0; 434175107Sfenner} 434226175Sfenner 4343190225Srpaulo#endif /* HAVE_PF_PACKET_SOCKETS */ 4344190225Srpaulo 4345190225Srpaulo/* ===== Functions to interface to the older kernels ================== */ 4346190225Srpaulo 434775107Sfenner/* 4348190225Srpaulo * Try to open a packet socket using the old kernel interface. 4349190225Srpaulo * Returns 1 on success and a PCAP_ERROR_ value on an error. 435075107Sfenner */ 435175107Sfennerstatic int 4352190225Srpauloactivate_old(pcap_t *handle) 435375107Sfenner{ 4354127664Sbms int arptype; 435575107Sfenner struct ifreq ifr; 4356190225Srpaulo const char *device = handle->opt.source; 4357190225Srpaulo struct utsname utsname; 4358190225Srpaulo int mtu; 435975107Sfenner 4360190225Srpaulo /* Open the socket */ 436175107Sfenner 4362190225Srpaulo handle->fd = socket(PF_INET, SOCK_PACKET, htons(ETH_P_ALL)); 4363190225Srpaulo if (handle->fd == -1) { 4364190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 4365190225Srpaulo "socket: %s", pcap_strerror(errno)); 4366190225Srpaulo return PCAP_ERROR_PERM_DENIED; 4367190225Srpaulo } 436875107Sfenner 4369190225Srpaulo /* It worked - we are using the old interface */ 4370190225Srpaulo handle->md.sock_packet = 1; 437175107Sfenner 4372190225Srpaulo /* ...which means we get the link-layer header. */ 4373190225Srpaulo handle->md.cooked = 0; 437475107Sfenner 4375190225Srpaulo /* Bind to the given device */ 437675107Sfenner 4377214518Srpaulo if (strcmp(device, "any") == 0) { 4378190225Srpaulo strncpy(handle->errbuf, "pcap_activate: The \"any\" device isn't supported on 2.0[.x]-kernel systems", 4379190225Srpaulo PCAP_ERRBUF_SIZE); 4380190225Srpaulo return PCAP_ERROR; 4381190225Srpaulo } 4382190225Srpaulo if (iface_bind_old(handle->fd, device, handle->errbuf) == -1) 4383190225Srpaulo return PCAP_ERROR; 438475107Sfenner 4385190225Srpaulo /* 4386190225Srpaulo * Try to get the link-layer type. 4387190225Srpaulo */ 4388190225Srpaulo arptype = iface_get_arptype(handle->fd, device, handle->errbuf); 4389190225Srpaulo if (arptype < 0) 4390190225Srpaulo return PCAP_ERROR; 4391127664Sbms 4392190225Srpaulo /* 4393190225Srpaulo * Try to find the DLT_ type corresponding to that 4394190225Srpaulo * link-layer type. 4395190225Srpaulo */ 4396190225Srpaulo map_arphrd_to_dlt(handle, arptype, 0); 4397190225Srpaulo if (handle->linktype == -1) { 4398190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 4399190225Srpaulo "unknown arptype %d", arptype); 4400190225Srpaulo return PCAP_ERROR; 4401190225Srpaulo } 4402127664Sbms 4403190225Srpaulo /* Go to promisc mode if requested */ 4404127664Sbms 4405190225Srpaulo if (handle->opt.promisc) { 4406190225Srpaulo memset(&ifr, 0, sizeof(ifr)); 4407190225Srpaulo strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); 4408190225Srpaulo if (ioctl(handle->fd, SIOCGIFFLAGS, &ifr) == -1) { 4409190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 4410190225Srpaulo "SIOCGIFFLAGS: %s", pcap_strerror(errno)); 4411190225Srpaulo return PCAP_ERROR; 4412190225Srpaulo } 4413190225Srpaulo if ((ifr.ifr_flags & IFF_PROMISC) == 0) { 4414190225Srpaulo /* 4415190225Srpaulo * Promiscuous mode isn't currently on, 4416190225Srpaulo * so turn it on, and remember that 4417190225Srpaulo * we should turn it off when the 4418190225Srpaulo * pcap_t is closed. 4419190225Srpaulo */ 442075107Sfenner 4421190225Srpaulo /* 4422190225Srpaulo * If we haven't already done so, arrange 4423190225Srpaulo * to have "pcap_close_all()" called when 4424190225Srpaulo * we exit. 4425190225Srpaulo */ 4426190225Srpaulo if (!pcap_do_addexit(handle)) { 442775107Sfenner /* 4428190225Srpaulo * "atexit()" failed; don't put 4429190225Srpaulo * the interface in promiscuous 4430190225Srpaulo * mode, just give up. 443175107Sfenner */ 4432190225Srpaulo return PCAP_ERROR; 4433190225Srpaulo } 443475107Sfenner 4435190225Srpaulo ifr.ifr_flags |= IFF_PROMISC; 4436190225Srpaulo if (ioctl(handle->fd, SIOCSIFFLAGS, &ifr) == -1) { 4437190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 4438190225Srpaulo "SIOCSIFFLAGS: %s", 4439190225Srpaulo pcap_strerror(errno)); 4440190225Srpaulo return PCAP_ERROR; 4441190225Srpaulo } 4442214518Srpaulo handle->md.must_do_on_close |= MUST_CLEAR_PROMISC; 444375107Sfenner 4444190225Srpaulo /* 4445190225Srpaulo * Add this to the list of pcaps 4446190225Srpaulo * to close when we exit. 4447190225Srpaulo */ 4448190225Srpaulo pcap_add_to_pcaps_to_close(handle); 444975107Sfenner } 4450190225Srpaulo } 445175107Sfenner 4452190225Srpaulo /* 4453190225Srpaulo * Compute the buffer size. 4454190225Srpaulo * 4455190225Srpaulo * We're using SOCK_PACKET, so this might be a 2.0[.x] 4456190225Srpaulo * kernel, and might require special handling - check. 4457190225Srpaulo */ 4458190225Srpaulo if (uname(&utsname) < 0 || 4459190225Srpaulo strncmp(utsname.release, "2.0", 3) == 0) { 446098530Sfenner /* 4461190225Srpaulo * Either we couldn't find out what kernel release 4462190225Srpaulo * this is, or it's a 2.0[.x] kernel. 4463190225Srpaulo * 4464190225Srpaulo * In the 2.0[.x] kernel, a "recvfrom()" on 4465190225Srpaulo * a SOCK_PACKET socket, with MSG_TRUNC set, will 4466190225Srpaulo * return the number of bytes read, so if we pass 4467190225Srpaulo * a length based on the snapshot length, it'll 4468190225Srpaulo * return the number of bytes from the packet 4469190225Srpaulo * copied to userland, not the actual length 4470190225Srpaulo * of the packet. 4471190225Srpaulo * 4472190225Srpaulo * This means that, for example, the IP dissector 4473190225Srpaulo * in tcpdump will get handed a packet length less 4474190225Srpaulo * than the length in the IP header, and will 4475190225Srpaulo * complain about "truncated-ip". 4476190225Srpaulo * 4477190225Srpaulo * So we don't bother trying to copy from the 4478190225Srpaulo * kernel only the bytes in which we're interested, 4479190225Srpaulo * but instead copy them all, just as the older 4480190225Srpaulo * versions of libpcap for Linux did. 4481190225Srpaulo * 4482190225Srpaulo * The buffer therefore needs to be big enough to 4483190225Srpaulo * hold the largest packet we can get from this 4484190225Srpaulo * device. Unfortunately, we can't get the MRU 4485190225Srpaulo * of the network; we can only get the MTU. The 4486190225Srpaulo * MTU may be too small, in which case a packet larger 4487190225Srpaulo * than the buffer size will be truncated *and* we 4488190225Srpaulo * won't get the actual packet size. 4489190225Srpaulo * 4490190225Srpaulo * However, if the snapshot length is larger than 4491190225Srpaulo * the buffer size based on the MTU, we use the 4492190225Srpaulo * snapshot length as the buffer size, instead; 4493190225Srpaulo * this means that with a sufficiently large snapshot 4494190225Srpaulo * length we won't artificially truncate packets 4495190225Srpaulo * to the MTU-based size. 4496190225Srpaulo * 4497190225Srpaulo * This mess just one of many problems with packet 4498190225Srpaulo * capture on 2.0[.x] kernels; you really want a 4499190225Srpaulo * 2.2[.x] or later kernel if you want packet capture 4500190225Srpaulo * to work well. 450198530Sfenner */ 4502190225Srpaulo mtu = iface_get_mtu(handle->fd, device, handle->errbuf); 4503190225Srpaulo if (mtu == -1) 4504190225Srpaulo return PCAP_ERROR; 4505190225Srpaulo handle->bufsize = MAX_LINKHEADER_SIZE + mtu; 4506190225Srpaulo if (handle->bufsize < handle->snapshot) 4507190225Srpaulo handle->bufsize = handle->snapshot; 4508190225Srpaulo } else { 4509190225Srpaulo /* 4510190225Srpaulo * This is a 2.2[.x] or later kernel. 4511190225Srpaulo * 4512190225Srpaulo * We can safely pass "recvfrom()" a byte count 4513190225Srpaulo * based on the snapshot length. 4514190225Srpaulo */ 4515190225Srpaulo handle->bufsize = handle->snapshot; 4516190225Srpaulo } 451798530Sfenner 4518190225Srpaulo /* 4519190225Srpaulo * Default value for offset to align link-layer payload 4520190225Srpaulo * on a 4-byte boundary. 4521190225Srpaulo */ 4522190225Srpaulo handle->offset = 0; 452375107Sfenner 4524190225Srpaulo return 1; 452575107Sfenner} 452675107Sfenner 452775107Sfenner/* 4528127664Sbms * Bind the socket associated with FD to the given device using the 452975107Sfenner * interface of the old kernels. 453075107Sfenner */ 453175107Sfennerstatic int 453275107Sfenneriface_bind_old(int fd, const char *device, char *ebuf) 453375107Sfenner{ 453475107Sfenner struct sockaddr saddr; 4535127664Sbms int err; 4536127664Sbms socklen_t errlen = sizeof(err); 453775107Sfenner 453875107Sfenner memset(&saddr, 0, sizeof(saddr)); 453975107Sfenner strncpy(saddr.sa_data, device, sizeof(saddr.sa_data)); 454075107Sfenner if (bind(fd, &saddr, sizeof(saddr)) == -1) { 454175107Sfenner snprintf(ebuf, PCAP_ERRBUF_SIZE, 454275107Sfenner "bind: %s", pcap_strerror(errno)); 454375107Sfenner return -1; 454426175Sfenner } 454526175Sfenner 4546127664Sbms /* Any pending errors, e.g., network is down? */ 4547127664Sbms 4548127664Sbms if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &errlen) == -1) { 4549127664Sbms snprintf(ebuf, PCAP_ERRBUF_SIZE, 4550127664Sbms "getsockopt: %s", pcap_strerror(errno)); 4551127664Sbms return -1; 4552127664Sbms } 4553127664Sbms 4554127664Sbms if (err > 0) { 4555127664Sbms snprintf(ebuf, PCAP_ERRBUF_SIZE, 4556127664Sbms "bind: %s", pcap_strerror(err)); 4557127664Sbms return -1; 4558127664Sbms } 4559127664Sbms 456075107Sfenner return 0; 456126175Sfenner} 456226175Sfenner 456375107Sfenner 456475107Sfenner/* ===== System calls available on all supported kernels ============== */ 456575107Sfenner 456675107Sfenner/* 4567127664Sbms * Query the kernel for the MTU of the given interface. 456875107Sfenner */ 456975107Sfennerstatic int 457075107Sfenneriface_get_mtu(int fd, const char *device, char *ebuf) 457126175Sfenner{ 457275107Sfenner struct ifreq ifr; 457326175Sfenner 457475107Sfenner if (!device) 457575107Sfenner return BIGGER_THAN_ALL_MTUS; 457675107Sfenner 457775107Sfenner memset(&ifr, 0, sizeof(ifr)); 457875107Sfenner strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); 457975107Sfenner 458075107Sfenner if (ioctl(fd, SIOCGIFMTU, &ifr) == -1) { 458175107Sfenner snprintf(ebuf, PCAP_ERRBUF_SIZE, 4582172677Smlaier "SIOCGIFMTU: %s", pcap_strerror(errno)); 458375107Sfenner return -1; 458475107Sfenner } 458575107Sfenner 458675107Sfenner return ifr.ifr_mtu; 458726175Sfenner} 458826175Sfenner 458975107Sfenner/* 459075107Sfenner * Get the hardware type of the given interface as ARPHRD_xxx constant. 459175107Sfenner */ 459275107Sfennerstatic int 459375107Sfenneriface_get_arptype(int fd, const char *device, char *ebuf) 459426175Sfenner{ 459575107Sfenner struct ifreq ifr; 459626175Sfenner 459775107Sfenner memset(&ifr, 0, sizeof(ifr)); 459875107Sfenner strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); 459975107Sfenner 460075107Sfenner if (ioctl(fd, SIOCGIFHWADDR, &ifr) == -1) { 460175107Sfenner snprintf(ebuf, PCAP_ERRBUF_SIZE, 4602172677Smlaier "SIOCGIFHWADDR: %s", pcap_strerror(errno)); 4603190225Srpaulo if (errno == ENODEV) { 4604190225Srpaulo /* 4605190225Srpaulo * No such device. 4606190225Srpaulo */ 4607190225Srpaulo return PCAP_ERROR_NO_SUCH_DEVICE; 4608190225Srpaulo } 4609190225Srpaulo return PCAP_ERROR; 461075107Sfenner } 461175107Sfenner 461275107Sfenner return ifr.ifr_hwaddr.sa_family; 461326175Sfenner} 461475107Sfenner 461598530Sfenner#ifdef SO_ATTACH_FILTER 461675107Sfennerstatic int 4617214518Srpaulofix_program(pcap_t *handle, struct sock_fprog *fcode, int is_mmapped) 461875107Sfenner{ 461975107Sfenner size_t prog_size; 462075107Sfenner register int i; 462175107Sfenner register struct bpf_insn *p; 462275107Sfenner struct bpf_insn *f; 462375107Sfenner int len; 462475107Sfenner 462575107Sfenner /* 462675107Sfenner * Make a copy of the filter, and modify that copy if 462775107Sfenner * necessary. 462875107Sfenner */ 462975107Sfenner prog_size = sizeof(*handle->fcode.bf_insns) * handle->fcode.bf_len; 463075107Sfenner len = handle->fcode.bf_len; 463175107Sfenner f = (struct bpf_insn *)malloc(prog_size); 463275107Sfenner if (f == NULL) { 4633190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 463475107Sfenner "malloc: %s", pcap_strerror(errno)); 463575107Sfenner return -1; 463675107Sfenner } 463775107Sfenner memcpy(f, handle->fcode.bf_insns, prog_size); 463875107Sfenner fcode->len = len; 463975107Sfenner fcode->filter = (struct sock_filter *) f; 464075107Sfenner 464175107Sfenner for (i = 0; i < len; ++i) { 464275107Sfenner p = &f[i]; 464375107Sfenner /* 464475107Sfenner * What type of instruction is this? 464575107Sfenner */ 464675107Sfenner switch (BPF_CLASS(p->code)) { 464775107Sfenner 464875107Sfenner case BPF_RET: 464975107Sfenner /* 4650214518Srpaulo * It's a return instruction; are we capturing 4651214518Srpaulo * in memory-mapped mode? 465275107Sfenner */ 4653214518Srpaulo if (!is_mmapped) { 465475107Sfenner /* 4655214518Srpaulo * No; is the snapshot length a constant, 4656214518Srpaulo * rather than the contents of the 4657214518Srpaulo * accumulator? 465875107Sfenner */ 4659214518Srpaulo if (BPF_MODE(p->code) == BPF_K) { 4660214518Srpaulo /* 4661214518Srpaulo * Yes - if the value to be returned, 4662214518Srpaulo * i.e. the snapshot length, is 4663214518Srpaulo * anything other than 0, make it 4664214518Srpaulo * 65535, so that the packet is 4665214518Srpaulo * truncated by "recvfrom()", 4666214518Srpaulo * not by the filter. 4667214518Srpaulo * 4668214518Srpaulo * XXX - there's nothing we can 4669214518Srpaulo * easily do if it's getting the 4670214518Srpaulo * value from the accumulator; we'd 4671214518Srpaulo * have to insert code to force 4672214518Srpaulo * non-zero values to be 65535. 4673214518Srpaulo */ 4674214518Srpaulo if (p->k != 0) 4675214518Srpaulo p->k = 65535; 4676214518Srpaulo } 467775107Sfenner } 467875107Sfenner break; 467975107Sfenner 468075107Sfenner case BPF_LD: 468175107Sfenner case BPF_LDX: 468275107Sfenner /* 468375107Sfenner * It's a load instruction; is it loading 468475107Sfenner * from the packet? 468575107Sfenner */ 468675107Sfenner switch (BPF_MODE(p->code)) { 468775107Sfenner 468875107Sfenner case BPF_ABS: 468975107Sfenner case BPF_IND: 469075107Sfenner case BPF_MSH: 469175107Sfenner /* 469275107Sfenner * Yes; are we in cooked mode? 469375107Sfenner */ 469475107Sfenner if (handle->md.cooked) { 469575107Sfenner /* 469675107Sfenner * Yes, so we need to fix this 469775107Sfenner * instruction. 469875107Sfenner */ 469975107Sfenner if (fix_offset(p) < 0) { 470075107Sfenner /* 470175107Sfenner * We failed to do so. 470275107Sfenner * Return 0, so our caller 470375107Sfenner * knows to punt to userland. 470475107Sfenner */ 470575107Sfenner return 0; 470675107Sfenner } 470775107Sfenner } 470875107Sfenner break; 470975107Sfenner } 471075107Sfenner break; 471175107Sfenner } 471275107Sfenner } 471375107Sfenner return 1; /* we succeeded */ 471475107Sfenner} 471575107Sfenner 471675107Sfennerstatic int 471775107Sfennerfix_offset(struct bpf_insn *p) 471875107Sfenner{ 471975107Sfenner /* 472075107Sfenner * What's the offset? 472175107Sfenner */ 472275107Sfenner if (p->k >= SLL_HDR_LEN) { 472375107Sfenner /* 472475107Sfenner * It's within the link-layer payload; that starts at an 472575107Sfenner * offset of 0, as far as the kernel packet filter is 472675107Sfenner * concerned, so subtract the length of the link-layer 472775107Sfenner * header. 472875107Sfenner */ 472975107Sfenner p->k -= SLL_HDR_LEN; 473075107Sfenner } else if (p->k == 14) { 473175107Sfenner /* 473275107Sfenner * It's the protocol field; map it to the special magic 473375107Sfenner * kernel offset for that field. 473475107Sfenner */ 473575107Sfenner p->k = SKF_AD_OFF + SKF_AD_PROTOCOL; 473675107Sfenner } else { 473775107Sfenner /* 473875107Sfenner * It's within the header, but it's not one of those 473975107Sfenner * fields; we can't do that in the kernel, so punt 474075107Sfenner * to userland. 474175107Sfenner */ 474275107Sfenner return -1; 474375107Sfenner } 474475107Sfenner return 0; 474575107Sfenner} 474698530Sfenner 474798530Sfennerstatic int 474898530Sfennerset_kernel_filter(pcap_t *handle, struct sock_fprog *fcode) 474998530Sfenner{ 475098530Sfenner int total_filter_on = 0; 475198530Sfenner int save_mode; 475298530Sfenner int ret; 475398530Sfenner int save_errno; 475498530Sfenner 475598530Sfenner /* 475698530Sfenner * The socket filter code doesn't discard all packets queued 475798530Sfenner * up on the socket when the filter is changed; this means 475898530Sfenner * that packets that don't match the new filter may show up 475998530Sfenner * after the new filter is put onto the socket, if those 476098530Sfenner * packets haven't yet been read. 476198530Sfenner * 476298530Sfenner * This means, for example, that if you do a tcpdump capture 476398530Sfenner * with a filter, the first few packets in the capture might 476498530Sfenner * be packets that wouldn't have passed the filter. 476598530Sfenner * 476698530Sfenner * We therefore discard all packets queued up on the socket 476798530Sfenner * when setting a kernel filter. (This isn't an issue for 476898530Sfenner * userland filters, as the userland filtering is done after 476998530Sfenner * packets are queued up.) 477098530Sfenner * 477198530Sfenner * To flush those packets, we put the socket in read-only mode, 477298530Sfenner * and read packets from the socket until there are no more to 477398530Sfenner * read. 477498530Sfenner * 477598530Sfenner * In order to keep that from being an infinite loop - i.e., 477698530Sfenner * to keep more packets from arriving while we're draining 477798530Sfenner * the queue - we put the "total filter", which is a filter 477898530Sfenner * that rejects all packets, onto the socket before draining 477998530Sfenner * the queue. 478098530Sfenner * 478198530Sfenner * This code deliberately ignores any errors, so that you may 478298530Sfenner * get bogus packets if an error occurs, rather than having 478398530Sfenner * the filtering done in userland even if it could have been 478498530Sfenner * done in the kernel. 478598530Sfenner */ 4786127664Sbms if (setsockopt(handle->fd, SOL_SOCKET, SO_ATTACH_FILTER, 478798530Sfenner &total_fcode, sizeof(total_fcode)) == 0) { 478898530Sfenner char drain[1]; 478998530Sfenner 479098530Sfenner /* 479198530Sfenner * Note that we've put the total filter onto the socket. 479298530Sfenner */ 479398530Sfenner total_filter_on = 1; 479498530Sfenner 479598530Sfenner /* 479698530Sfenner * Save the socket's current mode, and put it in 479798530Sfenner * non-blocking mode; we drain it by reading packets 4798127664Sbms * until we get an error (which is normally a 479998530Sfenner * "nothing more to be read" error). 480098530Sfenner */ 480198530Sfenner save_mode = fcntl(handle->fd, F_GETFL, 0); 480298530Sfenner if (save_mode != -1 && 480398530Sfenner fcntl(handle->fd, F_SETFL, save_mode | O_NONBLOCK) >= 0) { 480498530Sfenner while (recv(handle->fd, &drain, sizeof drain, 480598530Sfenner MSG_TRUNC) >= 0) 480698530Sfenner ; 4807127664Sbms save_errno = errno; 480898530Sfenner fcntl(handle->fd, F_SETFL, save_mode); 4809127664Sbms if (save_errno != EAGAIN) { 4810127664Sbms /* Fatal error */ 4811127664Sbms reset_kernel_filter(handle); 4812190225Srpaulo snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, 4813127664Sbms "recv: %s", pcap_strerror(save_errno)); 4814127664Sbms return -2; 4815127664Sbms } 481698530Sfenner } 481798530Sfenner } 481898530Sfenner 481998530Sfenner /* 482098530Sfenner * Now attach the new filter. 482198530Sfenner */ 4822127664Sbms ret = setsockopt(handle->fd, SOL_SOCKET, SO_ATTACH_FILTER, 482398530Sfenner fcode, sizeof(*fcode)); 482498530Sfenner if (ret == -1 && total_filter_on) { 482598530Sfenner /* 482698530Sfenner * Well, we couldn't set that filter on the socket, 482798530Sfenner * but we could set the total filter on the socket. 482898530Sfenner * 482998530Sfenner * This could, for example, mean that the filter was 483098530Sfenner * too big to put into the kernel, so we'll have to 483198530Sfenner * filter in userland; in any case, we'll be doing 483298530Sfenner * filtering in userland, so we need to remove the 483398530Sfenner * total filter so we see packets. 483498530Sfenner */ 483598530Sfenner save_errno = errno; 483698530Sfenner 483798530Sfenner /* 483898530Sfenner * XXX - if this fails, we're really screwed; 483998530Sfenner * we have the total filter on the socket, 484098530Sfenner * and it won't come off. What do we do then? 484198530Sfenner */ 484298530Sfenner reset_kernel_filter(handle); 484398530Sfenner 484498530Sfenner errno = save_errno; 484598530Sfenner } 4846127664Sbms return ret; 484798530Sfenner} 484898530Sfenner 484998530Sfennerstatic int 485098530Sfennerreset_kernel_filter(pcap_t *handle) 485198530Sfenner{ 4852172677Smlaier /* 4853172677Smlaier * setsockopt() barfs unless it get a dummy parameter. 4854172677Smlaier * valgrind whines unless the value is initialized, 4855172677Smlaier * as it has no idea that setsockopt() ignores its 4856172677Smlaier * parameter. 4857172677Smlaier */ 4858172677Smlaier int dummy = 0; 485998530Sfenner 486098530Sfenner return setsockopt(handle->fd, SOL_SOCKET, SO_DETACH_FILTER, 486198530Sfenner &dummy, sizeof(dummy)); 486298530Sfenner} 486375107Sfenner#endif 4864