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 * $FreeBSD: src/usr.sbin/ppp/arp.c,v 1.46.26.1 2010/12/21 17:10:29 kensmith 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 "ncpaddr.h" 61 #include "ipcp.h" 62 #include "ipv6cp.h" 63 #include "descriptor.h" 64 #include "lcp.h" 65 #include "ccp.h" 66 #include "link.h" 67 #include "mp.h" 68 #include "ncp.h" 69 #include "filter.h" 70 #ifndef NORADIUS 71 #include "radius.h" 72 #endif 73 #include "bundle.h" 74 #include "iface.h" 75 #include "arp.h" 76 77 /* 78 * SET_SA_FAMILY - set the sa_family field of a struct sockaddr, 79 * if it exists. 80 */ 81 #define SET_SA_FAMILY(addr, family) \ 82 memset((char *) &(addr), '\0', sizeof(addr)); \ 83 addr.sa_family = (family); \ 84 addr.sa_len = sizeof(addr); 85 86 87 #if RTM_VERSION >= 3 88 89 /* 90 * arp_SetProxy - Make a proxy ARP entry for the peer. 91 */ 92 static struct { 93 struct rt_msghdr hdr; 94 struct sockaddr_inarp dst; 95 struct sockaddr_dl hwa; 96 char extra[128]; 97 } arpmsg; 98 99 static int 100 arp_ProxySub(struct bundle *bundle, struct in_addr addr, int add) 101 { 102 int routes; 103 104 /* 105 * Get the hardware address of an interface on the same subnet as our local 106 * address. 107 */ 108 109 memset(&arpmsg, 0, sizeof arpmsg); 110 if (!arp_EtherAddr(addr, &arpmsg.hwa, 0)) { 111 log_Printf(LogWARN, "%s: Cannot determine ethernet address for proxy ARP\n", 112 inet_ntoa(addr)); 113 return 0; 114 } 115 routes = ID0socket(PF_ROUTE, SOCK_RAW, AF_INET); 116 if (routes < 0) { 117 log_Printf(LogERROR, "arp_SetProxy: opening routing socket: %s\n", 118 strerror(errno)); 119 return 0; 120 } 121 arpmsg.hdr.rtm_type = add ? RTM_ADD : RTM_DELETE; 122 arpmsg.hdr.rtm_flags = RTF_ANNOUNCE | RTF_HOST | RTF_STATIC; 123 arpmsg.hdr.rtm_version = RTM_VERSION; 124 arpmsg.hdr.rtm_seq = ++bundle->routing_seq; 125 arpmsg.hdr.rtm_addrs = RTA_DST | RTA_GATEWAY; 126 arpmsg.hdr.rtm_inits = RTV_EXPIRE; 127 arpmsg.dst.sin_len = sizeof(struct sockaddr_inarp); 128 arpmsg.dst.sin_family = AF_INET; 129 arpmsg.dst.sin_addr.s_addr = addr.s_addr; 130 arpmsg.dst.sin_other = SIN_PROXY; 131 132 arpmsg.hdr.rtm_msglen = (char *) &arpmsg.hwa - (char *) &arpmsg 133 + arpmsg.hwa.sdl_len; 134 135 136 if (ID0write(routes, &arpmsg, arpmsg.hdr.rtm_msglen) < 0 && 137 !(!add && errno == ESRCH)) { 138 log_Printf(LogERROR, "%s proxy arp entry %s: %s\n", 139 add ? "Add" : "Delete", inet_ntoa(addr), strerror(errno)); 140 close(routes); 141 return 0; 142 } 143 close(routes); 144 return 1; 145 } 146 147 int 148 arp_SetProxy(struct bundle *bundle, struct in_addr addr) 149 { 150 return (arp_ProxySub(bundle, addr, 1)); 151 } 152 153 /* 154 * arp_ClearProxy - Delete the proxy ARP entry for the peer. 155 */ 156 int 157 arp_ClearProxy(struct bundle *bundle, struct in_addr addr) 158 { 159 return (arp_ProxySub(bundle, addr, 0)); 160 } 161 162 #else /* RTM_VERSION */ 163 164 /* 165 * arp_SetProxy - Make a proxy ARP entry for the peer. 166 */ 167 int 168 arp_SetProxy(struct bundle *bundle, struct in_addr addr, int s) 169 { 170 struct arpreq arpreq; 171 struct { 172 struct sockaddr_dl sdl; 173 char space[128]; 174 } dls; 175 176 memset(&arpreq, '\0', sizeof arpreq); 177 178 /* 179 * Get the hardware address of an interface on the same subnet as our local 180 * address. 181 */ 182 if (!arp_EtherAddr(addr, &dls.sdl, 1)) { 183 log_Printf(LOG_PHASE_BIT, "Cannot determine ethernet address for " 184 "proxy ARP\n"); 185 return 0; 186 } 187 arpreq.arp_ha.sa_len = sizeof(struct sockaddr); 188 arpreq.arp_ha.sa_family = AF_UNSPEC; 189 memcpy(arpreq.arp_ha.sa_data, LLADDR(&dls.sdl), dls.sdl.sdl_alen); 190 SET_SA_FAMILY(arpreq.arp_pa, AF_INET); 191 ((struct sockaddr_in *)&arpreq.arp_pa)->sin_addr.s_addr = addr.s_addr; 192 arpreq.arp_flags = ATF_PERM | ATF_PUBL; 193 if (ID0ioctl(s, SIOCSARP, (caddr_t) & arpreq) < 0) { 194 log_Printf(LogERROR, "arp_SetProxy: ioctl(SIOCSARP): %s\n", 195 strerror(errno)); 196 return 0; 197 } 198 return 1; 199 } 200 201 /* 202 * arp_ClearProxy - Delete the proxy ARP entry for the peer. 203 */ 204 int 205 arp_ClearProxy(struct bundle *bundle, struct in_addr addr, int s) 206 { 207 struct arpreq arpreq; 208 209 memset(&arpreq, '\0', sizeof arpreq); 210 SET_SA_FAMILY(arpreq.arp_pa, AF_INET); 211 ((struct sockaddr_in *)&arpreq.arp_pa)->sin_addr.s_addr = addr.s_addr; 212 if (ID0ioctl(s, SIOCDARP, (caddr_t) & arpreq) < 0) { 213 log_Printf(LogERROR, "arp_ClearProxy: ioctl(SIOCDARP): %s\n", 214 strerror(errno)); 215 return 0; 216 } 217 return 1; 218 } 219 220 #endif /* RTM_VERSION */ 221 222 223 /* 224 * arp_EtherAddr - get the hardware address of an interface on the 225 * the same subnet as ipaddr. 226 */ 227 228 int 229 arp_EtherAddr(struct in_addr ipaddr, struct sockaddr_dl *hwaddr, 230 int verbose) 231 { 232 int mib[6], skip; 233 size_t needed; 234 char *buf, *ptr, *end; 235 struct if_msghdr *ifm; 236 struct ifa_msghdr *ifam; 237 struct sockaddr_dl *dl; 238 struct sockaddr *sa[RTAX_MAX]; 239 240 mib[0] = CTL_NET; 241 mib[1] = PF_ROUTE; 242 mib[2] = 0; 243 mib[3] = 0; 244 mib[4] = NET_RT_IFLIST; 245 mib[5] = 0; 246 247 if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0) { 248 log_Printf(LogERROR, "arp_EtherAddr: sysctl: estimate: %s\n", 249 strerror(errno)); 250 return 0; 251 } 252 253 if ((buf = malloc(needed)) == NULL) 254 return 0; 255 256 if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) { 257 free(buf); 258 return 0; 259 } 260 end = buf + needed; 261 262 ptr = buf; 263 while (ptr < end) { 264 ifm = (struct if_msghdr *)ptr; /* On if_msghdr */ 265 if (ifm->ifm_type != RTM_IFINFO) 266 break; 267 dl = (struct sockaddr_dl *)(ifm + 1); /* Single _dl at end */ 268 skip = (ifm->ifm_flags & (IFF_UP | IFF_BROADCAST | IFF_POINTOPOINT | 269 IFF_NOARP | IFF_LOOPBACK)) != (IFF_UP | IFF_BROADCAST); 270 ptr += ifm->ifm_msglen; /* First ifa_msghdr */ 271 while (ptr < end) { 272 ifam = (struct ifa_msghdr *)ptr; /* Next ifa_msghdr (alias) */ 273 if (ifam->ifam_type != RTM_NEWADDR) /* finished ? */ 274 break; 275 ptr += ifam->ifam_msglen; 276 if (skip || (ifam->ifam_addrs & (RTA_NETMASK|RTA_IFA)) != 277 (RTA_NETMASK|RTA_IFA)) 278 continue; 279 /* Found a candidate. Do the addresses match ? */ 280 if (log_IsKept(LogDEBUG) && 281 ptr == (char *)ifm + ifm->ifm_msglen + ifam->ifam_msglen) 282 log_Printf(LogDEBUG, "%.*s interface is a candidate for proxy\n", 283 dl->sdl_nlen, dl->sdl_data); 284 285 iface_ParseHdr(ifam, sa); 286 287 if (sa[RTAX_IFA]->sa_family == AF_INET) { 288 struct sockaddr_in *ifa, *netmask; 289 290 ifa = (struct sockaddr_in *)sa[RTAX_IFA]; 291 netmask = (struct sockaddr_in *)sa[RTAX_NETMASK]; 292 293 if (log_IsKept(LogDEBUG)) { 294 char a[16]; 295 296 strncpy(a, inet_ntoa(netmask->sin_addr), sizeof a - 1); 297 a[sizeof a - 1] = '\0'; 298 log_Printf(LogDEBUG, "Check addr %s, mask %s\n", 299 inet_ntoa(ifa->sin_addr), a); 300 } 301 302 if ((ifa->sin_addr.s_addr & netmask->sin_addr.s_addr) == 303 (ipaddr.s_addr & netmask->sin_addr.s_addr)) { 304 log_Printf(verbose ? LogPHASE : LogDEBUG, 305 "Found interface %.*s for %s\n", dl->sdl_nlen, 306 dl->sdl_data, inet_ntoa(ipaddr)); 307 memcpy(hwaddr, dl, dl->sdl_len); 308 free(buf); 309 return 1; 310 } 311 } 312 } 313 } 314 free(buf); 315 316 return 0; 317 } 318
