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 1.33 1999/04/26 08:54:24 brian Exp $ 21 * 22 */ 23 24 /* 25 * TODO: 26 */ 27 28 #include <sys/param.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 <errno.h> 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include <string.h> 44 #include <sys/sysctl.h> 45 #include <termios.h> 46 #include <unistd.h> 47 48 #include "layer.h" 49 #include "mbuf.h" 50 #include "log.h" 51 #include "id.h" 52 #include "timer.h" 53 #include "fsm.h" 54 #include "defs.h" 55 #include "iplist.h" 56 #include "throughput.h" 57 #include "slcompress.h" 58 #include "lqr.h" 59 #include "hdlc.h" 60 #include "ipcp.h" 61 #include "filter.h" 62 #include "descriptor.h" 63 #include "lcp.h" 64 #include "ccp.h" 65 #include "link.h" 66 #include "mp.h" 67 #ifndef NORADIUS 68 #include "radius.h" 69 #endif 70 #include "bundle.h" 71 #include "arp.h" 72 73 /* 74 * SET_SA_FAMILY - set the sa_family field of a struct sockaddr, 75 * if it exists. 76 */ 77 #define SET_SA_FAMILY(addr, family) \ 78 memset((char *) &(addr), '\0', sizeof(addr)); \ 79 addr.sa_family = (family); \ 80 addr.sa_len = sizeof(addr); 81 82 83 #if RTM_VERSION >= 3 84 85 /* 86 * arp_SetProxy - Make a proxy ARP entry for the peer. 87 */ 88 static struct { 89 struct rt_msghdr hdr; 90 struct sockaddr_inarp dst; 91 struct sockaddr_dl hwa; 92 char extra[128]; 93 } arpmsg; 94 95 static int 96 arp_ProxySub(struct bundle *bundle, struct in_addr addr, int add, int s) 97 { 98 int routes; 99 100 /* 101 * Get the hardware address of an interface on the same subnet as our local 102 * address. 103 */ 104 105 memset(&arpmsg, 0, sizeof arpmsg); 106 if (!get_ether_addr(s, addr, &arpmsg.hwa)) { 107 log_Printf(LogWARN, "%s: Cannot determine ethernet address for proxy ARP\n", 108 inet_ntoa(addr)); 109 return 0; 110 } 111 routes = ID0socket(PF_ROUTE, SOCK_RAW, AF_INET); 112 if (routes < 0) { 113 log_Printf(LogERROR, "arp_SetProxy: opening routing socket: %s\n", 114 strerror(errno)); 115 return 0; 116 } 117 arpmsg.hdr.rtm_type = add ? RTM_ADD : RTM_DELETE; 118 arpmsg.hdr.rtm_flags = RTF_ANNOUNCE | RTF_HOST | RTF_STATIC; 119 arpmsg.hdr.rtm_version = RTM_VERSION; 120 arpmsg.hdr.rtm_seq = ++bundle->routing_seq; 121 arpmsg.hdr.rtm_addrs = RTA_DST | RTA_GATEWAY; 122 arpmsg.hdr.rtm_inits = RTV_EXPIRE; 123 arpmsg.dst.sin_len = sizeof(struct sockaddr_inarp); 124 arpmsg.dst.sin_family = AF_INET; 125 arpmsg.dst.sin_addr.s_addr = addr.s_addr; 126 arpmsg.dst.sin_other = SIN_PROXY; 127 128 arpmsg.hdr.rtm_msglen = (char *) &arpmsg.hwa - (char *) &arpmsg 129 + arpmsg.hwa.sdl_len; 130 131 132 if (write(routes, &arpmsg, arpmsg.hdr.rtm_msglen) < 0 && 133 !(!add && errno == ESRCH)) { 134 log_Printf(LogERROR, "%s proxy arp entry %s: %s\n", 135 add ? "Add" : "Delete", inet_ntoa(addr), strerror(errno)); 136 close(routes); 137 return 0; 138 } 139 close(routes); 140 return 1; 141 } 142 143 int 144 arp_SetProxy(struct bundle *bundle, struct in_addr addr, int s) 145 { 146 147 return (arp_ProxySub(bundle, addr, 1, s)); 148 } 149 150 /* 151 * arp_ClearProxy - Delete the proxy ARP entry for the peer. 152 */ 153 int 154 arp_ClearProxy(struct bundle *bundle, struct in_addr addr, int s) 155 { 156 157 return (arp_ProxySub(bundle, addr, 0, s)); 158 } 159 160 #else /* RTM_VERSION */ 161 162 /* 163 * arp_SetProxy - Make a proxy ARP entry for the peer. 164 */ 165 int 166 arp_SetProxy(struct bundle *bundle, struct in_addr addr, int s) 167 { 168 struct arpreq arpreq; 169 struct { 170 struct sockaddr_dl sdl; 171 char space[128]; 172 } dls; 173 174 memset(&arpreq, '\0', sizeof arpreq); 175 176 /* 177 * Get the hardware address of an interface on the same subnet as our local 178 * address. 179 */ 180 if (!get_ether_addr(s, addr, &dls.sdl)) { 181 log_Printf(LOG_PHASE_BIT, "Cannot determine ethernet address for proxy ARP\n"); 182 return 0; 183 } 184 arpreq.arp_ha.sa_len = sizeof(struct sockaddr); 185 arpreq.arp_ha.sa_family = AF_UNSPEC; 186 memcpy(arpreq.arp_ha.sa_data, LLADDR(&dls.sdl), dls.sdl.sdl_alen); 187 SET_SA_FAMILY(arpreq.arp_pa, AF_INET); 188 ((struct sockaddr_in *)&arpreq.arp_pa)->sin_addr.s_addr = addr.s_addr; 189 arpreq.arp_flags = ATF_PERM | ATF_PUBL; 190 if (ID0ioctl(s, SIOCSARP, (caddr_t) & arpreq) < 0) { 191 log_Printf(LogERROR, "arp_SetProxy: ioctl(SIOCSARP): %s\n", 192 strerror(errno)); 193 return 0; 194 } 195 return 1; 196 } 197 198 /* 199 * arp_ClearProxy - Delete the proxy ARP entry for the peer. 200 */ 201 int 202 arp_ClearProxy(struct bundle *bundle, struct in_addr addr, int s) 203 { 204 struct arpreq arpreq; 205 206 memset(&arpreq, '\0', sizeof arpreq); 207 SET_SA_FAMILY(arpreq.arp_pa, AF_INET); 208 ((struct sockaddr_in *)&arpreq.arp_pa)->sin_addr.s_addr = addr.s_addr; 209 if (ID0ioctl(s, SIOCDARP, (caddr_t) & arpreq) < 0) { 210 log_Printf(LogERROR, "arp_ClearProxy: ioctl(SIOCDARP): %s\n", 211 strerror(errno)); 212 return 0; 213 } 214 return 1; 215 } 216 217 #endif /* RTM_VERSION */ 218 219 220 /* 221 * get_ether_addr - get the hardware address of an interface on the 222 * the same subnet as ipaddr. 223 */ 224 225 int 226 get_ether_addr(int s, struct in_addr ipaddr, struct sockaddr_dl *hwaddr) 227 { 228 int mib[6], sa_len, skip, b; 229 size_t needed; 230 char *buf, *ptr, *end; 231 struct if_msghdr *ifm; 232 struct ifa_msghdr *ifam; 233 struct sockaddr *sa; 234 struct sockaddr_dl *dl; 235 struct sockaddr_in *ifa, *mask; 236 237 mib[0] = CTL_NET; 238 mib[1] = PF_ROUTE; 239 mib[2] = 0; 240 mib[3] = 0; 241 mib[4] = NET_RT_IFLIST; 242 mib[5] = 0; 243 244 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) { 245 log_Printf(LogERROR, "get_ether_addr: sysctl: estimate: %s\n", 246 strerror(errno)); 247 return 0; 248 } 249 250 if ((buf = malloc(needed)) == NULL) 251 return 0; 252 253 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) { 254 free(buf); 255 return 0; 256 } 257 end = buf + needed; 258 259 ptr = buf; 260 while (ptr < end) { 261 ifm = (struct if_msghdr *)ptr; /* On if_msghdr */ 262 if (ifm->ifm_type != RTM_IFINFO) 263 break; 264 dl = (struct sockaddr_dl *)(ifm + 1); /* Single _dl at end */ 265 skip = (ifm->ifm_flags & (IFF_UP | IFF_BROADCAST | IFF_POINTOPOINT | 266 IFF_NOARP | IFF_LOOPBACK)) != (IFF_UP | IFF_BROADCAST); 267 ptr += ifm->ifm_msglen; /* First ifa_msghdr */ 268 while (ptr < end) { 269 ifam = (struct ifa_msghdr *)ptr; /* Next ifa_msghdr (alias) */ 270 if (ifam->ifam_type != RTM_NEWADDR) /* finished ? */ 271 break; 272 sa = (struct sockaddr *)(ifam+1); /* pile of sa's at end */ 273 ptr += ifam->ifam_msglen; 274 if (skip || (ifam->ifam_addrs & (RTA_NETMASK|RTA_IFA)) != 275 (RTA_NETMASK|RTA_IFA)) 276 continue; 277 /* Found a candidate. Do the addresses match ? */ 278 if (log_IsKept(LogDEBUG) && 279 ptr == (char *)ifm + ifm->ifm_msglen + ifam->ifam_msglen) 280 log_Printf(LogDEBUG, "%.*s interface is a candidate for proxy\n", 281 dl->sdl_nlen, dl->sdl_data); 282 b = 1; 283 ifa = mask = NULL; 284 while (b < (RTA_NETMASK|RTA_IFA) && sa < (struct sockaddr *)ptr) { 285 switch (b) { 286 case RTA_IFA: 287 ifa = (struct sockaddr_in *)sa; 288 break; 289 case RTA_NETMASK: 290 /* 291 * Careful here ! this sockaddr doesn't have sa_family set to 292 * AF_INET, and is only 8 bytes big ! I have no idea why ! 293 */ 294 mask = (struct sockaddr_in *)sa; 295 break; 296 } 297 if (ifam->ifam_addrs & b) { 298 #define ALN sizeof(ifa->sin_addr.s_addr) 299 sa_len = sa->sa_len > 0 ? ((sa->sa_len-1)|(ALN-1))+1 : ALN; 300 sa = (struct sockaddr *)((char *)sa + sa_len); 301 } 302 b <<= 1; 303 } 304 if (log_IsKept(LogDEBUG)) { 305 char a[16]; 306 strncpy(a, inet_ntoa(mask->sin_addr), sizeof a - 1); 307 a[sizeof a - 1] = '\0'; 308 log_Printf(LogDEBUG, "Check addr %s, mask %s\n", 309 inet_ntoa(ifa->sin_addr), a); 310 } 311 if (ifa->sin_family == AF_INET && 312 (ifa->sin_addr.s_addr & mask->sin_addr.s_addr) == 313 (ipaddr.s_addr & mask->sin_addr.s_addr)) { 314 log_Printf(LogPHASE, "Found interface %.*s for %s\n", 315 dl->sdl_alen, dl->sdl_data, inet_ntoa(ipaddr)); 316 memcpy(hwaddr, dl, dl->sdl_len); 317 free(buf); 318 return 1; 319 } 320 } 321 } 322 free(buf); 323 324 return 0; 325 } 326