1 /* 2 * sys-bsd.c - System-dependent procedures for setting up 3 * PPP interfaces on bsd-4.4-ish systems (including 386BSD, NetBSD, etc.) 4 * 5 * Copyright (c) 1989 Carnegie Mellon University. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms are permitted 9 * provided that the above copyright notice and this paragraph are 10 * duplicated in all such forms and that any documentation, 11 * advertising materials, and other materials related to such 12 * distribution and use acknowledge that the software was developed 13 * by Carnegie Mellon University. The name of the 14 * University may not be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 18 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 19 * 20 * $Id: arp.c,v 1.29 1998/06/16 19:40:34 brian Exp $ 21 * 22 */ 23 24 /* 25 * TODO: 26 */ 27 28 #include <sys/types.h> 29 #include <sys/socket.h> 30 #include <net/if.h> 31 #include <net/route.h> 32 #include <net/if_dl.h> 33 #include <netinet/in.h> 34 #include <netinet/if_ether.h> 35 #include <arpa/inet.h> 36 #include <netinet/in_systm.h> 37 #include <netinet/ip.h> 38 #include <sys/un.h> 39 40 #include <stdio.h> 41 #include <stdlib.h> 42 #include <string.h> 43 #include <sys/errno.h> 44 #include <sys/sysctl.h> 45 #include <unistd.h> 46 47 #include "mbuf.h" 48 #include "log.h" 49 #include "id.h" 50 #include "timer.h" 51 #include "fsm.h" 52 #include "defs.h" 53 #include "iplist.h" 54 #include "throughput.h" 55 #include "slcompress.h" 56 #include "lqr.h" 57 #include "hdlc.h" 58 #include "ipcp.h" 59 #include "filter.h" 60 #include "descriptor.h" 61 #include "lcp.h" 62 #include "ccp.h" 63 #include "link.h" 64 #include "mp.h" 65 #include "bundle.h" 66 #include "arp.h" 67 68 /* 69 * SET_SA_FAMILY - set the sa_family field of a struct sockaddr, 70 * if it exists. 71 */ 72 #define SET_SA_FAMILY(addr, family) \ 73 memset((char *) &(addr), '\0', sizeof(addr)); \ 74 addr.sa_family = (family); \ 75 addr.sa_len = sizeof(addr); 76 77 78 #if RTM_VERSION >= 3 79 80 /* 81 * arp_SetProxy - Make a proxy ARP entry for the peer. 82 */ 83 static struct { 84 struct rt_msghdr hdr; 85 struct sockaddr_inarp dst; 86 struct sockaddr_dl hwa; 87 char extra[128]; 88 } arpmsg; 89 90 static int arpmsg_valid; 91 92 int 93 arp_SetProxy(struct bundle *bundle, struct in_addr addr, int s) 94 { 95 int routes; 96 97 /* 98 * Get the hardware address of an interface on the same subnet as our local 99 * address. 100 */ 101 memset(&arpmsg, 0, sizeof arpmsg); 102 if (!get_ether_addr(s, addr, &arpmsg.hwa)) { 103 log_Printf(LogWARN, "Cannot determine ethernet address for proxy ARP\n"); 104 return 0; 105 } 106 routes = ID0socket(PF_ROUTE, SOCK_RAW, AF_INET); 107 if (routes < 0) { 108 log_Printf(LogERROR, "arp_SetProxy: opening routing socket: %s\n", 109 strerror(errno)); 110 return 0; 111 } 112 arpmsg.hdr.rtm_type = RTM_ADD; 113 arpmsg.hdr.rtm_flags = RTF_ANNOUNCE | RTF_HOST | RTF_STATIC; 114 arpmsg.hdr.rtm_version = RTM_VERSION; 115 arpmsg.hdr.rtm_seq = ++bundle->routing_seq; 116 arpmsg.hdr.rtm_addrs = RTA_DST | RTA_GATEWAY; 117 arpmsg.hdr.rtm_inits = RTV_EXPIRE; 118 arpmsg.dst.sin_len = sizeof(struct sockaddr_inarp); 119 arpmsg.dst.sin_family = AF_INET; 120 arpmsg.dst.sin_addr.s_addr = addr.s_addr; 121 arpmsg.dst.sin_other = SIN_PROXY; 122 123 arpmsg.hdr.rtm_msglen = (char *) &arpmsg.hwa - (char *) &arpmsg 124 + arpmsg.hwa.sdl_len; 125 if (write(routes, &arpmsg, arpmsg.hdr.rtm_msglen) < 0) { 126 log_Printf(LogERROR, "Add proxy arp entry: %s\n", strerror(errno)); 127 close(routes); 128 return 0; 129 } 130 close(routes); 131 arpmsg_valid = 1; 132 return 1; 133 } 134 135 /* 136 * arp_ClearProxy - Delete the proxy ARP entry for the peer. 137 */ 138 int 139 arp_ClearProxy(struct bundle *bundle, struct in_addr addr, int s) 140 { 141 int routes; 142 143 if (!arpmsg_valid) 144 return 0; 145 arpmsg_valid = 0; 146 147 arpmsg.hdr.rtm_type = RTM_DELETE; 148 arpmsg.hdr.rtm_seq = ++bundle->routing_seq; 149 150 routes = ID0socket(PF_ROUTE, SOCK_RAW, AF_INET); 151 if (routes < 0) { 152 log_Printf(LogERROR, "arp_SetProxy: opening routing socket: %s\n", 153 strerror(errno)); 154 return 0; 155 } 156 if (write(routes, &arpmsg, arpmsg.hdr.rtm_msglen) < 0) { 157 log_Printf(LogERROR, "Delete proxy arp entry: %s\n", strerror(errno)); 158 close(routes); 159 return 0; 160 } 161 close(routes); 162 return 1; 163 } 164 165 #else /* RTM_VERSION */ 166 167 /* 168 * arp_SetProxy - Make a proxy ARP entry for the peer. 169 */ 170 int 171 arp_SetProxy(struct bundle *bundle, struct in_addr addr, int s) 172 { 173 struct arpreq arpreq; 174 struct { 175 struct sockaddr_dl sdl; 176 char space[128]; 177 } dls; 178 179 memset(&arpreq, '\0', sizeof arpreq); 180 181 /* 182 * Get the hardware address of an interface on the same subnet as our local 183 * address. 184 */ 185 if (!get_ether_addr(s, addr, &dls.sdl)) { 186 log_Printf(LOG_PHASE_BIT, "Cannot determine ethernet address for proxy ARP\n"); 187 return 0; 188 } 189 arpreq.arp_ha.sa_len = sizeof(struct sockaddr); 190 arpreq.arp_ha.sa_family = AF_UNSPEC; 191 memcpy(arpreq.arp_ha.sa_data, LLADDR(&dls.sdl), dls.sdl.sdl_alen); 192 SET_SA_FAMILY(arpreq.arp_pa, AF_INET); 193 ((struct sockaddr_in *)&arpreq.arp_pa)->sin_addr.s_addr = addr.s_addr; 194 arpreq.arp_flags = ATF_PERM | ATF_PUBL; 195 if (ID0ioctl(s, SIOCSARP, (caddr_t) & arpreq) < 0) { 196 log_Printf(LogERROR, "arp_SetProxy: ioctl(SIOCSARP): %s\n", 197 strerror(errno)); 198 return 0; 199 } 200 return 1; 201 } 202 203 /* 204 * arp_ClearProxy - Delete the proxy ARP entry for the peer. 205 */ 206 int 207 arp_ClearProxy(struct bundle *bundle, struct in_addr addr, int s) 208 { 209 struct arpreq arpreq; 210 211 memset(&arpreq, '\0', sizeof arpreq); 212 SET_SA_FAMILY(arpreq.arp_pa, AF_INET); 213 ((struct sockaddr_in *)&arpreq.arp_pa)->sin_addr.s_addr = addr.s_addr; 214 if (ID0ioctl(s, SIOCDARP, (caddr_t) & arpreq) < 0) { 215 log_Printf(LogERROR, "arp_ClearProxy: ioctl(SIOCDARP): %s\n", 216 strerror(errno)); 217 return 0; 218 } 219 return 1; 220 } 221 222 #endif /* RTM_VERSION */ 223 224 225 /* 226 * get_ether_addr - get the hardware address of an interface on the 227 * the same subnet as ipaddr. 228 */ 229 230 int 231 get_ether_addr(int s, struct in_addr ipaddr, struct sockaddr_dl *hwaddr) 232 { 233 int mib[6], sa_len, skip, b; 234 size_t needed; 235 char *buf, *ptr, *end; 236 struct if_msghdr *ifm; 237 struct ifa_msghdr *ifam; 238 struct sockaddr *sa; 239 struct sockaddr_dl *dl; 240 struct sockaddr_in *ifa, *mask; 241 242 mib[0] = CTL_NET; 243 mib[1] = PF_ROUTE; 244 mib[2] = 0; 245 mib[3] = 0; 246 mib[4] = NET_RT_IFLIST; 247 mib[5] = 0; 248 249 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) { 250 log_Printf(LogERROR, "get_ether_addr: sysctl: estimate: %s\n", 251 strerror(errno)); 252 return 0; 253 } 254 255 if ((buf = malloc(needed)) == NULL) 256 return 0; 257 258 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) { 259 free(buf); 260 return 0; 261 } 262 end = buf + needed; 263 264 ptr = buf; 265 while (ptr < end) { 266 ifm = (struct if_msghdr *)ptr; /* On if_msghdr */ 267 if (ifm->ifm_type != RTM_IFINFO) 268 break; 269 dl = (struct sockaddr_dl *)(ifm + 1); /* Single _dl at end */ 270 skip = (ifm->ifm_flags & (IFF_UP | IFF_BROADCAST | IFF_POINTOPOINT | 271 IFF_NOARP | IFF_LOOPBACK)) != (IFF_UP | IFF_BROADCAST); 272 ptr += ifm->ifm_msglen; /* First ifa_msghdr */ 273 while (ptr < end) { 274 ifam = (struct ifa_msghdr *)ptr; /* Next ifa_msghdr (alias) */ 275 if (ifam->ifam_type != RTM_NEWADDR) /* finished ? */ 276 break; 277 sa = (struct sockaddr *)(ifam+1); /* pile of sa's at end */ 278 ptr += ifam->ifam_msglen; 279 if (skip || (ifam->ifam_addrs & (RTA_NETMASK|RTA_IFA)) != 280 (RTA_NETMASK|RTA_IFA)) 281 continue; 282 /* Found a candidate. Do the addresses match ? */ 283 if (log_IsKept(LogDEBUG) && 284 ptr == (char *)ifm + ifm->ifm_msglen + ifam->ifam_msglen) 285 log_Printf(LogDEBUG, "%.*s interface is a candidate for proxy\n", 286 dl->sdl_nlen, dl->sdl_data); 287 b = 1; 288 ifa = mask = NULL; 289 while (b < (RTA_NETMASK|RTA_IFA) && sa < (struct sockaddr *)ptr) { 290 switch (b) { 291 case RTA_IFA: 292 ifa = (struct sockaddr_in *)sa; 293 break; 294 case RTA_NETMASK: 295 /* 296 * Careful here ! this sockaddr doesn't have sa_family set to 297 * AF_INET, and is only 8 bytes big ! I have no idea why ! 298 */ 299 mask = (struct sockaddr_in *)sa; 300 break; 301 } 302 if (ifam->ifam_addrs & b) { 303 #define ALN sizeof(ifa->sin_addr.s_addr) 304 sa_len = sa->sa_len > 0 ? ((sa->sa_len-1)|(ALN-1))+1 : ALN; 305 sa = (struct sockaddr *)((char *)sa + sa_len); 306 } 307 b <<= 1; 308 } 309 if (log_IsKept(LogDEBUG)) { 310 char a[16]; 311 strncpy(a, inet_ntoa(mask->sin_addr), sizeof a - 1); 312 a[sizeof a - 1] = '\0'; 313 log_Printf(LogDEBUG, "Check addr %s, mask %s\n", 314 inet_ntoa(ifa->sin_addr), a); 315 } 316 if (ifa->sin_family == AF_INET && 317 (ifa->sin_addr.s_addr & mask->sin_addr.s_addr) == 318 (ipaddr.s_addr & mask->sin_addr.s_addr)) { 319 log_Printf(LogPHASE, "Found interface %.*s for %s\n", 320 dl->sdl_alen, dl->sdl_data, inet_ntoa(ipaddr)); 321 memcpy(hwaddr, dl, dl->sdl_len); 322 free(buf); 323 return 1; 324 } 325 } 326 } 327 free(buf); 328 329 return 0; 330 } 331