arp.c revision 36285
16735Samurai/* 26735Samurai * sys-bsd.c - System-dependent procedures for setting up 36735Samurai * PPP interfaces on bsd-4.4-ish systems (including 386BSD, NetBSD, etc.) 46735Samurai * 56735Samurai * Copyright (c) 1989 Carnegie Mellon University. 66735Samurai * All rights reserved. 76735Samurai * 86735Samurai * Redistribution and use in source and binary forms are permitted 96735Samurai * provided that the above copyright notice and this paragraph are 106735Samurai * duplicated in all such forms and that any documentation, 116735Samurai * advertising materials, and other materials related to such 126735Samurai * distribution and use acknowledge that the software was developed 136735Samurai * by Carnegie Mellon University. The name of the 146735Samurai * University may not be used to endorse or promote products derived 156735Samurai * from this software without specific prior written permission. 166735Samurai * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 176735Samurai * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 186735Samurai * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 198857Srgrimes * 2036285Sbrian * $Id: arp.c,v 1.27.2.15 1998/05/01 19:23:46 brian Exp $ 218857Srgrimes * 226735Samurai */ 236735Samurai 246735Samurai/* 256735Samurai * TODO: 266735Samurai */ 276735Samurai 2836285Sbrian#include <sys/types.h> 296735Samurai#include <sys/socket.h> 306735Samurai#include <net/if.h> 316735Samurai#include <net/route.h> 326735Samurai#include <net/if_dl.h> 336735Samurai#include <netinet/in.h> 346735Samurai#include <netinet/if_ether.h> 3532721Sbrian#include <arpa/inet.h> 3636285Sbrian#include <netinet/in_systm.h> 3736285Sbrian#include <netinet/ip.h> 3836285Sbrian#include <sys/un.h> 3930715Sbrian 4030715Sbrian#include <stdio.h> 4132616Sbrian#include <stdlib.h> 4230715Sbrian#include <string.h> 4330715Sbrian#include <sys/errno.h> 4432616Sbrian#include <sys/sysctl.h> 4530715Sbrian#include <unistd.h> 4630715Sbrian 4730715Sbrian#include "mbuf.h" 4829265Sbrian#include "log.h" 4931061Sbrian#include "id.h" 5036285Sbrian#include "timer.h" 5136285Sbrian#include "fsm.h" 5236285Sbrian#include "defs.h" 5336285Sbrian#include "iplist.h" 5436285Sbrian#include "throughput.h" 5536285Sbrian#include "slcompress.h" 5636285Sbrian#include "ipcp.h" 5736285Sbrian#include "filter.h" 5836285Sbrian#include "descriptor.h" 5936285Sbrian#include "lqr.h" 6036285Sbrian#include "hdlc.h" 6136285Sbrian#include "lcp.h" 6236285Sbrian#include "ccp.h" 6336285Sbrian#include "link.h" 6436285Sbrian#include "mp.h" 6536285Sbrian#include "bundle.h" 6630715Sbrian#include "arp.h" 676735Samurai 6832616Sbrian/* 696735Samurai * SET_SA_FAMILY - set the sa_family field of a struct sockaddr, 706735Samurai * if it exists. 716735Samurai */ 726735Samurai#define SET_SA_FAMILY(addr, family) \ 7330715Sbrian memset((char *) &(addr), '\0', sizeof(addr)); \ 746735Samurai addr.sa_family = (family); \ 756735Samurai addr.sa_len = sizeof(addr); 766735Samurai 776735Samurai 786735Samurai#if RTM_VERSION >= 3 796735Samurai 806735Samurai/* 8136285Sbrian * arp_SetProxy - Make a proxy ARP entry for the peer. 826735Samurai */ 836735Samuraistatic struct { 8428679Sbrian struct rt_msghdr hdr; 8528679Sbrian struct sockaddr_inarp dst; 8628679Sbrian struct sockaddr_dl hwa; 8728679Sbrian char extra[128]; 8830715Sbrian} arpmsg; 896735Samurai 906735Samuraistatic int arpmsg_valid; 916735Samurai 926735Samuraiint 9336285Sbrianarp_SetProxy(struct bundle *bundle, struct in_addr addr, int s) 946735Samurai{ 9528679Sbrian int routes; 966735Samurai 9728679Sbrian /* 9828679Sbrian * Get the hardware address of an interface on the same subnet as our local 9928679Sbrian * address. 10028679Sbrian */ 10131962Sbrian memset(&arpmsg, 0, sizeof arpmsg); 10236285Sbrian if (!get_ether_addr(s, addr, &arpmsg.hwa)) { 10336285Sbrian log_Printf(LogERROR, "Cannot determine ethernet address for proxy ARP\n"); 10428679Sbrian return 0; 10528679Sbrian } 10631061Sbrian routes = ID0socket(PF_ROUTE, SOCK_RAW, AF_INET); 10731061Sbrian if (routes < 0) { 10836285Sbrian log_Printf(LogERROR, "arp_SetProxy: opening routing socket: %s\n", 10928679Sbrian strerror(errno)); 11028679Sbrian return 0; 11128679Sbrian } 11228679Sbrian arpmsg.hdr.rtm_type = RTM_ADD; 11328679Sbrian arpmsg.hdr.rtm_flags = RTF_ANNOUNCE | RTF_HOST | RTF_STATIC; 11428679Sbrian arpmsg.hdr.rtm_version = RTM_VERSION; 11536285Sbrian arpmsg.hdr.rtm_seq = ++bundle->routing_seq; 11628679Sbrian arpmsg.hdr.rtm_addrs = RTA_DST | RTA_GATEWAY; 11728679Sbrian arpmsg.hdr.rtm_inits = RTV_EXPIRE; 11828679Sbrian arpmsg.dst.sin_len = sizeof(struct sockaddr_inarp); 11928679Sbrian arpmsg.dst.sin_family = AF_INET; 12036285Sbrian arpmsg.dst.sin_addr.s_addr = addr.s_addr; 12128679Sbrian arpmsg.dst.sin_other = SIN_PROXY; 1226735Samurai 12328679Sbrian arpmsg.hdr.rtm_msglen = (char *) &arpmsg.hwa - (char *) &arpmsg 12428679Sbrian + arpmsg.hwa.sdl_len; 12528679Sbrian if (write(routes, &arpmsg, arpmsg.hdr.rtm_msglen) < 0) { 12636285Sbrian log_Printf(LogERROR, "Add proxy arp entry: %s\n", strerror(errno)); 1276735Samurai close(routes); 12828679Sbrian return 0; 12928679Sbrian } 13028679Sbrian close(routes); 13128679Sbrian arpmsg_valid = 1; 13228679Sbrian return 1; 1336735Samurai} 1346735Samurai 1356735Samurai/* 13636285Sbrian * arp_ClearProxy - Delete the proxy ARP entry for the peer. 1376735Samurai */ 1386735Samuraiint 13936285Sbrianarp_ClearProxy(struct bundle *bundle, struct in_addr addr, int s) 1406735Samurai{ 14128679Sbrian int routes; 1426735Samurai 14328679Sbrian if (!arpmsg_valid) 14428679Sbrian return 0; 14528679Sbrian arpmsg_valid = 0; 1466735Samurai 14728679Sbrian arpmsg.hdr.rtm_type = RTM_DELETE; 14836285Sbrian arpmsg.hdr.rtm_seq = ++bundle->routing_seq; 1496735Samurai 15031061Sbrian routes = ID0socket(PF_ROUTE, SOCK_RAW, AF_INET); 15131061Sbrian if (routes < 0) { 15236285Sbrian log_Printf(LogERROR, "arp_SetProxy: opening routing socket: %s\n", 15328679Sbrian strerror(errno)); 15428679Sbrian return 0; 15528679Sbrian } 15628679Sbrian if (write(routes, &arpmsg, arpmsg.hdr.rtm_msglen) < 0) { 15736285Sbrian log_Printf(LogERROR, "Delete proxy arp entry: %s\n", strerror(errno)); 1586735Samurai close(routes); 15928679Sbrian return 0; 16028679Sbrian } 16128679Sbrian close(routes); 16228679Sbrian return 1; 1636735Samurai} 1646735Samurai 16528679Sbrian#else /* RTM_VERSION */ 1666735Samurai 1676735Samurai/* 16836285Sbrian * arp_SetProxy - Make a proxy ARP entry for the peer. 1696735Samurai */ 1706735Samuraiint 17136285Sbrianarp_SetProxy(struct bundle *bundle, struct in_addr addr, int s) 1726735Samurai{ 17328679Sbrian struct arpreq arpreq; 17428679Sbrian struct { 17528679Sbrian struct sockaddr_dl sdl; 17628679Sbrian char space[128]; 17728679Sbrian } dls; 1786735Samurai 17931962Sbrian memset(&arpreq, '\0', sizeof arpreq); 1806735Samurai 18128679Sbrian /* 18228679Sbrian * Get the hardware address of an interface on the same subnet as our local 18328679Sbrian * address. 18428679Sbrian */ 18536285Sbrian if (!get_ether_addr(s, addr, &dls.sdl)) { 18636285Sbrian log_Printf(LOG_PHASE_BIT, "Cannot determine ethernet address for proxy ARP\n"); 18728679Sbrian return 0; 18828679Sbrian } 18928679Sbrian arpreq.arp_ha.sa_len = sizeof(struct sockaddr); 19028679Sbrian arpreq.arp_ha.sa_family = AF_UNSPEC; 19130715Sbrian memcpy(arpreq.arp_ha.sa_data, LLADDR(&dls.sdl), dls.sdl.sdl_alen); 19228679Sbrian SET_SA_FAMILY(arpreq.arp_pa, AF_INET); 19336285Sbrian ((struct sockaddr_in *)&arpreq.arp_pa)->sin_addr.s_addr = addr.s_addr; 19428679Sbrian arpreq.arp_flags = ATF_PERM | ATF_PUBL; 19536285Sbrian if (ID0ioctl(s, SIOCSARP, (caddr_t) & arpreq) < 0) { 19636285Sbrian log_Printf(LogERROR, "arp_SetProxy: ioctl(SIOCSARP): %s\n", strerror(errno)); 19728679Sbrian return 0; 19828679Sbrian } 19928679Sbrian return 1; 2006735Samurai} 2016735Samurai 2026735Samurai/* 20336285Sbrian * arp_ClearProxy - Delete the proxy ARP entry for the peer. 2046735Samurai */ 2056735Samuraiint 20636285Sbrianarp_ClearProxy(struct bundle *bundle, struct in_addr addr, int s) 2076735Samurai{ 20828679Sbrian struct arpreq arpreq; 2096735Samurai 21031962Sbrian memset(&arpreq, '\0', sizeof arpreq); 21128679Sbrian SET_SA_FAMILY(arpreq.arp_pa, AF_INET); 21236285Sbrian ((struct sockaddr_in *)&arpreq.arp_pa)->sin_addr.s_addr = addr.s_addr; 21336285Sbrian if (ID0ioctl(s, SIOCDARP, (caddr_t) & arpreq) < 0) { 21436285Sbrian log_Printf(LogERROR, "arp_ClearProxy: ioctl(SIOCDARP): %s\n", strerror(errno)); 21528679Sbrian return 0; 21628679Sbrian } 21728679Sbrian return 1; 2186735Samurai} 2196735Samurai 22028679Sbrian#endif /* RTM_VERSION */ 2216735Samurai 22228679Sbrian 2236735Samurai/* 2246735Samurai * get_ether_addr - get the hardware address of an interface on the 2256735Samurai * the same subnet as ipaddr. 2266735Samurai */ 2276735Samurai 22836285Sbrianint 22932616Sbrianget_ether_addr(int s, struct in_addr ipaddr, struct sockaddr_dl *hwaddr) 2306735Samurai{ 23132721Sbrian int mib[6], sa_len, skip, b; 23232721Sbrian size_t needed; 23332721Sbrian char *buf, *ptr, *end; 23432721Sbrian struct if_msghdr *ifm; 23532721Sbrian struct ifa_msghdr *ifam; 23632721Sbrian struct sockaddr *sa; 23732616Sbrian struct sockaddr_dl *dl; 23832721Sbrian struct sockaddr_in *ifa, *mask; 2396735Samurai 24032616Sbrian mib[0] = CTL_NET; 24132616Sbrian mib[1] = PF_ROUTE; 24232616Sbrian mib[2] = 0; 24332616Sbrian mib[3] = 0; 24432721Sbrian mib[4] = NET_RT_IFLIST; 24532616Sbrian mib[5] = 0; 24632721Sbrian 24732616Sbrian if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) { 24836285Sbrian log_Printf(LogERROR, "get_ether_addr: sysctl: estimate: %s\n", 24932723Sbrian strerror(errno)); 25032616Sbrian return 0; 25128679Sbrian } 25232721Sbrian 25332721Sbrian if ((buf = malloc(needed)) == NULL) 25428679Sbrian return 0; 25532721Sbrian 25632721Sbrian if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) { 25732721Sbrian free(buf); 25832616Sbrian return 0; 25932616Sbrian } 26032721Sbrian end = buf + needed; 2616735Samurai 26232721Sbrian ptr = buf; 26332721Sbrian while (ptr < end) { 26432721Sbrian ifm = (struct if_msghdr *)ptr; /* On if_msghdr */ 26532721Sbrian if (ifm->ifm_type != RTM_IFINFO) 26632721Sbrian break; 26732721Sbrian dl = (struct sockaddr_dl *)(ifm + 1); /* Single _dl at end */ 26832721Sbrian skip = (ifm->ifm_flags & (IFF_UP | IFF_BROADCAST | IFF_POINTOPOINT | 26932721Sbrian IFF_NOARP | IFF_LOOPBACK)) != (IFF_UP | IFF_BROADCAST); 27032721Sbrian ptr += ifm->ifm_msglen; /* First ifa_msghdr */ 27132721Sbrian while (ptr < end) { 27232721Sbrian ifam = (struct ifa_msghdr *)ptr; /* Next ifa_msghdr (alias) */ 27332721Sbrian if (ifam->ifam_type != RTM_NEWADDR) /* finished ? */ 27432721Sbrian break; 27532721Sbrian sa = (struct sockaddr *)(ifam+1); /* pile of sa's at end */ 27632721Sbrian ptr += ifam->ifam_msglen; 27732721Sbrian if (skip || (ifam->ifam_addrs & (RTA_NETMASK|RTA_IFA)) != 27832721Sbrian (RTA_NETMASK|RTA_IFA)) 27932721Sbrian continue; 28032721Sbrian /* Found a candidate. Do the addresses match ? */ 28136285Sbrian if (log_IsKept(LogDEBUG) && 28232721Sbrian ptr == (char *)ifm + ifm->ifm_msglen + ifam->ifam_msglen) 28336285Sbrian log_Printf(LogDEBUG, "%.*s interface is a candidate for proxy\n", 28432721Sbrian dl->sdl_nlen, dl->sdl_data); 28532721Sbrian b = 1; 28632722Sbrian ifa = mask = NULL; 28732721Sbrian while (b < (RTA_NETMASK|RTA_IFA) && sa < (struct sockaddr *)ptr) { 28832721Sbrian switch (b) { 28932721Sbrian case RTA_IFA: 29032721Sbrian ifa = (struct sockaddr_in *)sa; 29132721Sbrian break; 29232721Sbrian case RTA_NETMASK: 29332721Sbrian /* 29432721Sbrian * Careful here ! this sockaddr doesn't have sa_family set to 29532721Sbrian * AF_INET, and is only 8 bytes big ! I have no idea why ! 29632721Sbrian */ 29732721Sbrian mask = (struct sockaddr_in *)sa; 29832721Sbrian break; 29932616Sbrian } 30032721Sbrian if (ifam->ifam_addrs & b) { 30132721Sbrian#define ALN sizeof(ifa->sin_addr.s_addr) 30232721Sbrian sa_len = sa->sa_len > 0 ? ((sa->sa_len-1)|(ALN-1))+1 : ALN; 30332721Sbrian sa = (struct sockaddr *)((char *)sa + sa_len); 30432721Sbrian } 30532721Sbrian b <<= 1; 30632616Sbrian } 30736285Sbrian if (log_IsKept(LogDEBUG)) { 30832721Sbrian char a[16]; 30932721Sbrian strncpy(a, inet_ntoa(mask->sin_addr), sizeof a - 1); 31032721Sbrian a[sizeof a - 1] = '\0'; 31136285Sbrian log_Printf(LogDEBUG, "Check addr %s, mask %s\n", 31232721Sbrian inet_ntoa(ifa->sin_addr), a); 31332721Sbrian } 31432721Sbrian if (ifa->sin_family == AF_INET && 31532721Sbrian (ifa->sin_addr.s_addr & mask->sin_addr.s_addr) == 31632721Sbrian (ipaddr.s_addr & mask->sin_addr.s_addr)) { 31736285Sbrian log_Printf(LogPHASE, "Found interface %.*s for %s\n", 31836285Sbrian dl->sdl_alen, dl->sdl_data, inet_ntoa(ipaddr)); 31932721Sbrian memcpy(hwaddr, dl, dl->sdl_len); 32032721Sbrian free(buf); 32132721Sbrian return 1; 32232721Sbrian } 3236735Samurai } 32428679Sbrian } 32532721Sbrian free(buf); 32632721Sbrian 32728679Sbrian return 0; 3286735Samurai} 329