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 1.11 1997/04/15 00:03:35 brian Exp $ 21 * 22 */ 23 24 /* 25 * TODO: 26 */ 27 28 #include <sys/ioctl.h> 29 #include <sys/types.h> 30 #include <sys/uio.h> 31 #include <sys/socket.h> 32 #include <sys/time.h> 33 #include <sys/errno.h> 34 #include <unistd.h> 35 #include <string.h> 36 37 #include <net/if.h> 38 #include <net/if_var.h> 39 #include <net/route.h> 40 #include <net/if_dl.h> 41 #include <netinet/in.h> 42 #include <stdio.h> 43 #include <fcntl.h> 44 #ifdef __bsdi__ 45 #include <kvm.h> 46 #endif 47 #include <net/if_types.h> 48 #include <netinet/in_var.h> 49 #include <netinet/if_ether.h> 50 #include "log.h" 51 52 #if RTM_VERSION >= 3 53 #include <netinet/if_ether.h> 54 #endif 55 56 static int rtm_seq; 57 58 static int get_ether_addr(int, u_long, struct sockaddr_dl *); 59 60 #define BCOPY(s, d, l) memcpy(d, s, l) 61 #define BZERO(s, n) memset(s, 0, n) 62 /* 63 * SET_SA_FAMILY - set the sa_family field of a struct sockaddr, 64 * if it exists. 65 */ 66 #define SET_SA_FAMILY(addr, family) \ 67 BZERO((char *) &(addr), sizeof(addr)); \ 68 addr.sa_family = (family); \ 69 addr.sa_len = sizeof(addr); 70 71 72 #if RTM_VERSION >= 3 73 74 /* 75 * sifproxyarp - Make a proxy ARP entry for the peer. 76 */ 77 static struct { 78 struct rt_msghdr hdr; 79 struct sockaddr_inarp dst; 80 struct sockaddr_dl hwa; 81 char extra[128]; 82 } arpmsg; 83 84 static int arpmsg_valid; 85 86 int 87 sifproxyarp(unit, hisaddr) 88 int unit; 89 u_long hisaddr; 90 { 91 int routes; 92 93 /* 94 * Get the hardware address of an interface on the same subnet 95 * as our local address. 96 */ 97 memset(&arpmsg, 0, sizeof(arpmsg)); 98 if (!get_ether_addr(unit, hisaddr, &arpmsg.hwa)) { 99 LogPrintf(LogERROR, "Cannot determine ethernet address" 100 " for proxy ARP\n"); 101 return 0; 102 } 103 104 if ((routes = socket(PF_ROUTE, SOCK_RAW, AF_INET)) < 0) { 105 LogPrintf(LogERROR, "sifproxyarp: opening routing socket: %s\n", 106 strerror(errno)); 107 return 0; 108 } 109 110 arpmsg.hdr.rtm_type = RTM_ADD; 111 arpmsg.hdr.rtm_flags = RTF_ANNOUNCE | RTF_HOST | RTF_STATIC; 112 arpmsg.hdr.rtm_version = RTM_VERSION; 113 arpmsg.hdr.rtm_seq = ++rtm_seq; 114 arpmsg.hdr.rtm_addrs = RTA_DST | RTA_GATEWAY; 115 arpmsg.hdr.rtm_inits = RTV_EXPIRE; 116 arpmsg.dst.sin_len = sizeof(struct sockaddr_inarp); 117 arpmsg.dst.sin_family = AF_INET; 118 arpmsg.dst.sin_addr.s_addr = hisaddr; 119 arpmsg.dst.sin_other = SIN_PROXY; 120 121 arpmsg.hdr.rtm_msglen = (char *) &arpmsg.hwa - (char *) &arpmsg 122 + arpmsg.hwa.sdl_len; 123 if (write(routes, &arpmsg, arpmsg.hdr.rtm_msglen) < 0) { 124 LogPrintf(LogERROR, "Add proxy arp entry: %s\n", strerror(errno)); 125 close(routes); 126 return 0; 127 } 128 129 close(routes); 130 arpmsg_valid = 1; 131 return 1; 132 } 133 134 /* 135 * cifproxyarp - Delete the proxy ARP entry for the peer. 136 */ 137 int 138 cifproxyarp(unit, hisaddr) 139 int unit; 140 u_long hisaddr; 141 { 142 int routes; 143 144 if (!arpmsg_valid) 145 return 0; 146 arpmsg_valid = 0; 147 148 arpmsg.hdr.rtm_type = RTM_DELETE; 149 arpmsg.hdr.rtm_seq = ++rtm_seq; 150 151 if ((routes = socket(PF_ROUTE, SOCK_RAW, AF_INET)) < 0) { 152 LogPrintf(LogERROR, "sifproxyarp: opening routing socket: %s\n", 153 strerror(errno)); 154 return 0; 155 } 156 157 if (write(routes, &arpmsg, arpmsg.hdr.rtm_msglen) < 0) { 158 LogPrintf(LogERROR, "Delete proxy arp entry: %s\n", strerror(errno)); 159 close(routes); 160 return 0; 161 } 162 163 close(routes); 164 return 1; 165 } 166 167 #else /* RTM_VERSION */ 168 169 /* 170 * sifproxyarp - Make a proxy ARP entry for the peer. 171 */ 172 int 173 sifproxyarp(unit, hisaddr) 174 int unit; 175 u_long hisaddr; 176 { 177 struct arpreq arpreq; 178 struct { 179 struct sockaddr_dl sdl; 180 char space[128]; 181 } dls; 182 183 BZERO(&arpreq, sizeof(arpreq)); 184 185 /* 186 * Get the hardware address of an interface on the same subnet 187 * as our local address. 188 */ 189 if (!get_ether_addr(unit, hisaddr, &dls.sdl)) { 190 LogPrintf(LOG_PHASE_BIT, "Cannot determine ethernet address for proxy ARP\n"); 191 return 0; 192 } 193 194 arpreq.arp_ha.sa_len = sizeof(struct sockaddr); 195 arpreq.arp_ha.sa_family = AF_UNSPEC; 196 BCOPY(LLADDR(&dls.sdl), arpreq.arp_ha.sa_data, dls.sdl.sdl_alen); 197 SET_SA_FAMILY(arpreq.arp_pa, AF_INET); 198 ((struct sockaddr_in *) &arpreq.arp_pa)->sin_addr.s_addr = hisaddr; 199 arpreq.arp_flags = ATF_PERM | ATF_PUBL; 200 if (ioctl(unit, SIOCSARP, (caddr_t)&arpreq) < 0) { 201 LogPrintf(LogERROR, "sifproxyarp: ioctl(SIOCSARP): \n"); 202 return 0; 203 } 204 205 return 1; 206 } 207 208 /* 209 * cifproxyarp - Delete the proxy ARP entry for the peer. 210 */ 211 int 212 cifproxyarp(unit, hisaddr) 213 int unit; 214 u_long hisaddr; 215 { 216 struct arpreq arpreq; 217 218 BZERO(&arpreq, sizeof(arpreq)); 219 SET_SA_FAMILY(arpreq.arp_pa, AF_INET); 220 ((struct sockaddr_in *) &arpreq.arp_pa)->sin_addr.s_addr = hisaddr; 221 if (ioctl(unit, SIOCDARP, (caddr_t)&arpreq) < 0) { 222 LogPrintf(LogERROR, "cifproxyarp: ioctl(SIOCDARP): \n"); 223 return 0; 224 } 225 return 1; 226 } 227 #endif /* RTM_VERSION */ 228 229 230 /* 231 * get_ether_addr - get the hardware address of an interface on the 232 * the same subnet as ipaddr. 233 */ 234 #define MAX_IFS 32 235 236 int 237 get_ether_addr(s, ipaddr, hwaddr) 238 int s; 239 u_long ipaddr; 240 struct sockaddr_dl *hwaddr; 241 { 242 struct ifreq *ifr, *ifend, *ifp; 243 u_long ina, mask; 244 struct sockaddr_dl *dla; 245 struct ifreq ifreq; 246 struct ifconf ifc; 247 struct ifreq ifs[MAX_IFS]; 248 249 ifc.ifc_len = sizeof(ifs); 250 ifc.ifc_req = ifs; 251 if (ioctl(s, SIOCGIFCONF, &ifc) < 0) { 252 LogPrintf(LogERROR, "get_ether_addr: ioctl(SIOCGIFCONF): \n"); 253 return 0; 254 } 255 256 /* 257 * Scan through looking for an interface with an Internet 258 * address on the same subnet as `ipaddr'. 259 */ 260 ifend = (struct ifreq *) (ifc.ifc_buf + ifc.ifc_len); 261 for (ifr = ifc.ifc_req; ifr < ifend; ) { 262 if (ifr->ifr_addr.sa_family == AF_INET) { 263 ina = ((struct sockaddr_in *) &ifr->ifr_addr)->sin_addr.s_addr; 264 strncpy(ifreq.ifr_name, ifr->ifr_name, sizeof(ifreq.ifr_name)); 265 ifreq.ifr_name[sizeof(ifreq.ifr_name)-1]='\0'; 266 /* 267 * Check that the interface is up, and not point-to-point 268 * or loopback. 269 */ 270 if (ioctl(s, SIOCGIFFLAGS, &ifreq) < 0) 271 continue; 272 if ((ifreq.ifr_flags & 273 (IFF_UP|IFF_BROADCAST|IFF_POINTOPOINT|IFF_LOOPBACK|IFF_NOARP)) 274 != (IFF_UP|IFF_BROADCAST)) 275 goto nextif; 276 /* 277 * Get its netmask and check that it's on the right subnet. 278 */ 279 if (ioctl(s, SIOCGIFNETMASK, &ifreq) < 0) 280 continue; 281 mask = ((struct sockaddr_in *) &ifreq.ifr_addr)->sin_addr.s_addr; 282 if ((ipaddr & mask) != (ina & mask)) 283 goto nextif; 284 285 break; 286 } 287 nextif: 288 ifr = (struct ifreq *) ((char *)&ifr->ifr_addr + ifr->ifr_addr.sa_len); 289 } 290 291 if (ifr >= ifend) 292 return 0; 293 LogPrintf(LogPHASE, "Found interface %s for proxy arp\n", ifr->ifr_name); 294 295 /* 296 * Now scan through again looking for a link-level address 297 * for this interface. 298 */ 299 ifp = ifr; 300 for (ifr = ifc.ifc_req; ifr < ifend; ) { 301 if (strcmp(ifp->ifr_name, ifr->ifr_name) == 0 302 && ifr->ifr_addr.sa_family == AF_LINK) { 303 /* 304 * Found the link-level address - copy it out 305 */ 306 dla = (struct sockaddr_dl *) &ifr->ifr_addr; 307 #ifdef __bsdi__ 308 if (dla->sdl_alen == 0) 309 kmemgetether(ifr->ifr_name, dla); 310 #endif 311 BCOPY(dla, hwaddr, dla->sdl_len); 312 return 1; 313 } 314 ifr = (struct ifreq *) ((char *)&ifr->ifr_addr + ifr->ifr_addr.sa_len); 315 } 316 317 return 0; 318 } 319 320 #ifdef __bsdi__ 321 #include <nlist.h> 322 323 struct nlist nl[] = { 324 #define N_IFNET 0 325 { "_ifnet" }, 326 "", 327 }; 328 329 330 kvm_t *kvmd; 331 332 /* 333 * Read kernel memory, return 0 on success. 334 */ 335 int 336 kread(addr, buf, size) 337 u_long addr; 338 char *buf; 339 int size; 340 { 341 if (kvm_read(kvmd, addr, buf, size) != size) { 342 /* XXX this duplicates kvm_read's error printout */ 343 LogPrintf(LogERROR, "kvm_read %s\n", kvm_geterr(kvmd)); 344 return -1; 345 } 346 return 0; 347 } 348 349 kmemgetether(ifname, dlo) 350 char *ifname; 351 struct sockaddr_dl *dlo; 352 { 353 struct ifnet ifnet; 354 int n; 355 u_long addr, ifaddraddr, ifnetfound, ifaddrfound; 356 char name[16+32]; 357 struct sockaddr *sa; 358 char *cp; 359 struct sockaddr_dl *sdl; 360 union { 361 struct ifaddr ifa; 362 struct in_ifaddr in; 363 } ifaddr; 364 struct arpcom ac; 365 366 kvmd = kvm_open(NULL, NULL, NULL, O_RDONLY, NULL); 367 if (kvmd) { 368 n = kvm_nlist(kvmd, nl); 369 if (n >= 0) { 370 addr = nl[N_IFNET].n_value; 371 kread(addr, (char *)&addr, sizeof(addr)); 372 ifaddraddr = ifnetfound = 0; 373 while (addr || ifaddraddr) { 374 ifnetfound = addr; 375 if (ifaddraddr == 0) { 376 if (kread(addr, (char *)&ifnet, sizeof(ifnet)) || 377 kread((u_long)ifnet.if_name, name, 16)) 378 return; 379 name[15] = 0; 380 addr = (u_long) ifnet.if_next; 381 cp = (char *)index(name, '\0'); 382 cp += sprintf(cp, "%d", ifnet.if_unit); 383 *cp = '\0'; 384 ifaddraddr = (u_long)ifnet.if_addrlist; 385 } 386 ifaddrfound = ifaddraddr; 387 if (ifaddraddr) { 388 if (kread(ifaddraddr, (char *)&ifaddr, sizeof ifaddr)) { 389 ifaddraddr = 0; 390 continue; 391 } 392 #define CP(x) ((char *)(x)) 393 cp = (CP(ifaddr.ifa.ifa_addr) - CP(ifaddraddr)) + CP(&ifaddr); 394 sa = (struct sockaddr *)cp; 395 if (sa->sa_family == AF_LINK && strcmp(ifname, name) == 0) { 396 sdl = (struct sockaddr_dl *)sa; 397 cp = (char *)LLADDR(sdl); 398 n = sdl->sdl_alen; 399 if (ifnet.if_type == IFT_ETHER) { 400 if (n == 0) { 401 kread(ifnetfound, (char *)&ac, sizeof(ac)); 402 cp = (char *)LLADDR(sdl); 403 bcopy((char *)ac.ac_enaddr, cp, 6); 404 sdl->sdl_alen = 6; 405 } 406 bcopy(sdl, dlo, sizeof(*sdl)); 407 return; 408 } 409 } 410 ifaddraddr = (u_long)ifaddr.ifa.ifa_next; 411 } 412 } 413 } 414 } 415 } 416 #endif 417 418 #ifdef DEBUG 419 main() 420 { 421 u_long ipaddr; 422 int s; 423 424 s = socket(AF_INET, SOCK_DGRAM, 0); 425 ipaddr = inet_addr("192.168.1.32"); 426 sifproxyarp(s, ipaddr); 427 close(s); 428 } 429 #endif 430