1/* $Id$ */ 2 3/*** 4 This file is part of avahi. 5 6 avahi is free software; you can redistribute it and/or modify it 7 under the terms of the GNU Lesser General Public License as 8 published by the Free Software Foundation; either version 2.1 of the 9 License, or (at your option) any later version. 10 11 avahi is distributed in the hope that it will be useful, but WITHOUT 12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 13 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General 14 Public License for more details. 15 16 You should have received a copy of the GNU Lesser General Public 17 License along with avahi; if not, write to the Free Software 18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 19 USA. 20***/ 21 22#ifdef HAVE_CONFIG_H 23#include <config.h> 24#endif 25 26#include <sys/socket.h> 27#include <errno.h> 28#include <string.h> 29#include <unistd.h> 30#include <arpa/inet.h> 31 32#include <linux/types.h> 33#include <linux/netlink.h> 34#include <linux/rtnetlink.h> 35#include <linux/if.h> 36#include <linux/if_arp.h> 37 38#include <libdaemon/dlog.h> 39 40#include <avahi-common/llist.h> 41#include <avahi-common/malloc.h> 42 43#ifndef IFLA_RTA 44#include <linux/if_addr.h> 45#define IFLA_RTA(r) ((struct rtattr*)(((char*)(r)) + NLMSG_ALIGN(sizeof(struct ifinfomsg)))) 46#endif 47 48#ifndef IFA_RTA 49#include <linux/if_addr.h> 50#define IFA_RTA(r) ((struct rtattr*)(((char*)(r)) + NLMSG_ALIGN(sizeof(struct ifaddrmsg)))) 51#endif 52 53#include "iface.h" 54 55static int fd = -1; 56static int ifindex = -1; 57 58typedef struct Address Address; 59 60struct Address { 61 uint32_t address; 62 AVAHI_LLIST_FIELDS(Address, addresses); 63}; 64 65AVAHI_LLIST_HEAD(Address, addresses) = NULL; 66 67int iface_init(int i) { 68 struct sockaddr_nl addr; 69 int on = 1; 70 71 if ((fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE)) < 0) { 72 daemon_log(LOG_ERR, "socket(PF_NETLINK): %s", strerror(errno)); 73 goto fail; 74 } 75 76 memset(&addr, 0, sizeof(addr)); 77 addr.nl_family = AF_NETLINK; 78 addr.nl_groups = RTMGRP_LINK|RTMGRP_IPV4_IFADDR; 79 addr.nl_pid = getpid(); 80 81 if (bind(fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) { 82 daemon_log(LOG_ERR, "bind(): %s", strerror(errno)); 83 goto fail; 84 } 85 86 if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)) < 0) { 87 daemon_log(LOG_ERR, "SO_PASSCRED: %s", strerror(errno)); 88 goto fail; 89 } 90 91 ifindex = i; 92 93 return fd; 94 95fail: 96 if (fd >= 0) { 97 close(fd); 98 fd = -1; 99 } 100 101 return -1; 102} 103 104static int process_nlmsg(struct nlmsghdr *n) { 105 assert(n); 106 107 if (n->nlmsg_type == RTM_NEWLINK || n->nlmsg_type == RTM_DELLINK) { 108 /* A link appeared or was removed */ 109 110 struct ifinfomsg *ifi; 111 ifi = NLMSG_DATA(n); 112 113 if (ifi->ifi_family != AF_UNSPEC || (int) ifi->ifi_index != ifindex) 114 return 0; 115 116 if (n->nlmsg_type == RTM_DELLINK) { 117 daemon_log(LOG_ERR, "Interface vanished."); 118 return -1; 119 } 120 121 assert(n->nlmsg_type == RTM_NEWLINK); 122 123 if ((ifi->ifi_flags & IFF_LOOPBACK) || 124 (ifi->ifi_flags & IFF_NOARP) || 125 ifi->ifi_type != ARPHRD_ETHER) { 126 daemon_log(LOG_ERR, "Interface not suitable."); 127 return -1; 128 } 129 130 } else if (n->nlmsg_type == RTM_NEWADDR || n->nlmsg_type == RTM_DELADDR) { 131 132 /* An address was added or removed */ 133 134 struct rtattr *a = NULL; 135 struct ifaddrmsg *ifa; 136 int l; 137 uint32_t address = 0; 138 Address *i; 139 140 ifa = NLMSG_DATA(n); 141 142 if (ifa->ifa_family != AF_INET || (int) ifa->ifa_index != ifindex) 143 return 0; 144 145 l = NLMSG_PAYLOAD(n, sizeof(*ifa)); 146 a = IFLA_RTA(ifa); 147 148 while(RTA_OK(a, l)) { 149 150 switch(a->rta_type) { 151 case IFA_LOCAL: 152 case IFA_ADDRESS: 153 assert(RTA_PAYLOAD(a) == 4); 154 memcpy(&address, RTA_DATA(a), sizeof(uint32_t)); 155 break; 156 } 157 158 a = RTA_NEXT(a, l); 159 } 160 161 if (!address || is_ll_address(address)) 162 return 0; 163 164 for (i = addresses; i; i = i->addresses_next) 165 if (i->address == address) 166 break; 167 168 if (n->nlmsg_type == RTM_DELADDR && i) { 169 AVAHI_LLIST_REMOVE(Address, addresses, addresses, i); 170 avahi_free(i); 171 } if (n->nlmsg_type == RTM_NEWADDR && !i) { 172 i = avahi_new(Address, 1); 173 i->address = address; 174 AVAHI_LLIST_PREPEND(Address, addresses, addresses, i); 175 } 176 } 177 178 return 0; 179} 180 181static int process_response(int wait_for_done, unsigned seq) { 182 assert(fd >= 0); 183 184 do { 185 size_t bytes; 186 ssize_t r; 187 char replybuf[8*1024]; 188 char cred_msg[CMSG_SPACE(sizeof(struct ucred))]; 189 struct msghdr msghdr; 190 struct cmsghdr *cmsghdr; 191 struct ucred *ucred; 192 struct iovec iov; 193 struct nlmsghdr *p = (struct nlmsghdr *) replybuf; 194 195 memset(&iov, 0, sizeof(iov)); 196 iov.iov_base = replybuf; 197 iov.iov_len = sizeof(replybuf); 198 199 memset(&msghdr, 0, sizeof(msghdr)); 200 msghdr.msg_name = (void*) NULL; 201 msghdr.msg_namelen = 0; 202 msghdr.msg_iov = &iov; 203 msghdr.msg_iovlen = 1; 204 msghdr.msg_control = cred_msg; 205 msghdr.msg_controllen = sizeof(cred_msg); 206 msghdr.msg_flags = 0; 207 208 if ((r = recvmsg(fd, &msghdr, 0)) < 0) { 209 daemon_log(LOG_ERR, "recvmsg() failed: %s", strerror(errno)); 210 return -1; 211 } 212 213 if (!(cmsghdr = CMSG_FIRSTHDR(&msghdr)) || cmsghdr->cmsg_type != SCM_CREDENTIALS) { 214 daemon_log(LOG_WARNING, "No sender credentials received, ignoring data."); 215 return -1; 216 } 217 218 ucred = (struct ucred*) CMSG_DATA(cmsghdr); 219 220 if (ucred->uid != 0) 221 return -1; 222 223 bytes = (size_t) r; 224 225 for (; bytes > 0; p = NLMSG_NEXT(p, bytes)) { 226 227 if (!NLMSG_OK(p, bytes) || bytes < sizeof(struct nlmsghdr) || bytes < p->nlmsg_len) { 228 daemon_log(LOG_ERR, "Netlink packet too small."); 229 return -1; 230 } 231 232 if (p->nlmsg_type == NLMSG_DONE && wait_for_done && p->nlmsg_seq == seq && (pid_t) p->nlmsg_pid == getpid()) 233 return 0; 234 235 if (p->nlmsg_type == NLMSG_ERROR) { 236 struct nlmsgerr *e = (struct nlmsgerr *) NLMSG_DATA (p); 237 238 if (e->error) { 239 daemon_log(LOG_ERR, "Netlink error: %s", strerror(-e->error)); 240 return -1; 241 } 242 } 243 244 if (process_nlmsg(p) < 0) 245 return -1; 246 } 247 } while (wait_for_done); 248 249 return 0; 250} 251 252int iface_get_initial_state(State *state) { 253 struct nlmsghdr *n; 254 struct ifinfomsg *ifi; 255 struct ifaddrmsg *ifa; 256 uint8_t req[1024]; 257 int seq = 0; 258 259 assert(fd >= 0); 260 assert(state); 261 262 memset(&req, 0, sizeof(req)); 263 n = (struct nlmsghdr*) req; 264 n->nlmsg_len = NLMSG_LENGTH(sizeof(*ifi)); 265 n->nlmsg_type = RTM_GETLINK; 266 n->nlmsg_seq = seq; 267 n->nlmsg_flags = NLM_F_MATCH|NLM_F_REQUEST|NLM_F_ACK; 268 n->nlmsg_pid = 0; 269 270 ifi = NLMSG_DATA(n); 271 ifi->ifi_family = AF_UNSPEC; 272 ifi->ifi_change = -1; 273 274 if (send(fd, n, n->nlmsg_len, 0) < 0) { 275 daemon_log(LOG_ERR, "send(): %s", strerror(errno)); 276 return -1; 277 } 278 279 if (process_response(1, 0) < 0) 280 return -1; 281 282 n->nlmsg_type = RTM_GETADDR; 283 n->nlmsg_len = NLMSG_LENGTH(sizeof(*ifa)); 284 n->nlmsg_seq = ++seq; 285 286 ifa = NLMSG_DATA(n); 287 ifa->ifa_family = AF_INET; 288 ifa->ifa_index = ifindex; 289 290 if (send(fd, n, n->nlmsg_len, 0) < 0) { 291 daemon_log(LOG_ERR, "send(): %s", strerror(errno)); 292 return -1; 293 } 294 295 if (process_response(1, seq) < 0) 296 return -1; 297 298 *state = addresses ? STATE_SLEEPING : STATE_START; 299 300 return 0; 301} 302 303int iface_process(Event *event) { 304 int b; 305 assert(fd >= 0); 306 307 b = !!addresses; 308 309 if (process_response(0, 0) < 0) 310 return -1; 311 312 if (b && !addresses) 313 *event = EVENT_ROUTABLE_ADDR_UNCONFIGURED; 314 else if (!b && addresses) 315 *event = EVENT_ROUTABLE_ADDR_CONFIGURED; 316 317 return 0; 318} 319 320void iface_done(void) { 321 Address *a; 322 323 if (fd >= 0) { 324 close(fd); 325 fd = -1; 326 } 327 328 while ((a = addresses)) { 329 AVAHI_LLIST_REMOVE(Address, addresses, addresses, a); 330 avahi_free(a); 331 } 332} 333 334 335