1 /* $OpenBSD: packet.c,v 1.12 2014/03/24 11:01:47 mpi Exp $ */ 2 3 /* 4 * Copyright (c) 2004, 2005 Esben Norby <norby@openbsd.org> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #include <sys/types.h> 20 #include <sys/socket.h> 21 #include <sys/uio.h> 22 23 #include <netinet/in.h> 24 #include <netinet/in_systm.h> 25 #include <netinet/ip.h> 26 #include <netinet/ip6.h> 27 #include <arpa/inet.h> 28 #include <net/if_dl.h> 29 30 #include <errno.h> 31 #include <event.h> 32 #include <limits.h> 33 #include <stdlib.h> 34 #include <string.h> 35 36 #include "ospf6d.h" 37 #include "ospf6.h" 38 #include "log.h" 39 #include "ospfe.h" 40 41 int ip_hdr_sanity_check(const struct ip6_hdr *, u_int16_t); 42 int ospf_hdr_sanity_check(struct ospf_hdr *, u_int16_t, 43 const struct iface *, struct in6_addr *); 44 struct iface *find_iface(struct ospfd_conf *, unsigned int, 45 struct in6_addr *); 46 47 int 48 gen_ospf_hdr(struct ibuf *buf, struct iface *iface, u_int8_t type) 49 { 50 struct ospf_hdr ospf_hdr; 51 52 bzero(&ospf_hdr, sizeof(ospf_hdr)); 53 ospf_hdr.version = OSPF6_VERSION; 54 ospf_hdr.type = type; 55 ospf_hdr.rtr_id = ospfe_router_id(); 56 if (iface->type != IF_TYPE_VIRTUALLINK) 57 ospf_hdr.area_id = iface->area_id.s_addr; 58 ospf_hdr.instance = DEFAULT_INSTANCE_ID; 59 ospf_hdr.zero = 0; /* must be zero */ 60 61 return (ibuf_add(buf, &ospf_hdr, sizeof(ospf_hdr))); 62 } 63 64 int 65 upd_ospf_hdr(struct ibuf *buf, struct iface *iface) 66 { 67 struct ospf_hdr *ospf_hdr; 68 69 if ((ospf_hdr = ibuf_seek(buf, 0, sizeof(ospf_hdr))) == NULL) 70 fatalx("upd_ospf_hdr: buf_seek failed"); 71 72 /* update length */ 73 if (buf->wpos > USHRT_MAX) 74 fatalx("upd_ospf_hdr: resulting ospf packet too big"); 75 ospf_hdr->len = htons((u_int16_t)buf->wpos); 76 ospf_hdr->chksum = 0; /* calculated via IPV6_CHECKSUM */ 77 78 return (0); 79 } 80 81 /* send and receive packets */ 82 int 83 send_packet(struct iface *iface, void *pkt, size_t len, 84 struct in6_addr *dst) 85 { 86 struct sockaddr_in6 sa6; 87 88 /* setup buffer */ 89 bzero(&sa6, sizeof(sa6)); 90 91 sa6.sin6_family = AF_INET6; 92 sa6.sin6_len = sizeof(sa6); 93 sa6.sin6_addr = *dst; 94 95 /* don't we all love link local scope and all the needed hacks for it */ 96 if (IN6_IS_ADDR_LINKLOCAL(dst) || IN6_IS_ADDR_MC_LINKLOCAL(dst)) 97 sa6.sin6_scope_id = iface->ifindex; 98 99 /* set outgoing interface for multicast traffic */ 100 if (IN6_IS_ADDR_MULTICAST(dst)) 101 if (if_set_mcast(iface) == -1) { 102 log_warn("send_packet: error setting multicast " 103 "interface, %s", iface->name); 104 return (-1); 105 } 106 107 if (sendto(iface->fd, pkt, len, 0, (struct sockaddr *)&sa6, 108 sizeof(sa6)) == -1) { 109 log_warn("send_packet: error sending packet on interface %s", 110 iface->name); 111 return (-1); 112 } 113 114 return (0); 115 } 116 117 void 118 recv_packet(int fd, short event, void *bula) 119 { 120 union { 121 struct cmsghdr hdr; 122 char buf[CMSG_SPACE(sizeof(struct in6_pktinfo))]; 123 } cmsgbuf; 124 struct msghdr msg; 125 struct iovec iov; 126 struct in6_addr addr, dest; 127 struct sockaddr_in6 src; 128 struct ospfd_conf *xconf = bula; 129 struct ospf_hdr *ospf_hdr; 130 struct iface *iface; 131 struct nbr *nbr = NULL; 132 char *buf; 133 struct cmsghdr *cmsg; 134 ssize_t r; 135 u_int16_t len; 136 int l; 137 unsigned int ifindex = 0; 138 139 if (event != EV_READ) 140 return; 141 142 /* setup buffer */ 143 bzero(&msg, sizeof(msg)); 144 iov.iov_base = buf = pkt_ptr; 145 iov.iov_len = READ_BUF_SIZE; 146 msg.msg_name = &src; 147 msg.msg_namelen = sizeof(src); 148 msg.msg_iov = &iov; 149 msg.msg_iovlen = 1; 150 msg.msg_control = &cmsgbuf.buf; 151 msg.msg_controllen = sizeof(cmsgbuf.buf); 152 153 if ((r = recvmsg(fd, &msg, 0)) == -1) { 154 if (errno != EAGAIN && errno != EINTR) 155 log_debug("recv_packet: read error: %s", 156 strerror(errno)); 157 return; 158 } 159 for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; 160 cmsg = CMSG_NXTHDR(&msg, cmsg)) { 161 if (cmsg->cmsg_level == IPPROTO_IPV6 && 162 cmsg->cmsg_type == IPV6_PKTINFO) { 163 ifindex = ((struct in6_pktinfo *) 164 CMSG_DATA(cmsg))->ipi6_ifindex; 165 dest = ((struct in6_pktinfo *) 166 CMSG_DATA(cmsg))->ipi6_addr; 167 break; 168 } 169 } 170 171 /* find a matching interface */ 172 if ((iface = find_iface(xconf, ifindex, &src.sin6_addr)) == NULL) { 173 /* XXX add a counter here */ 174 return; 175 } 176 /* 177 * Packet needs to be sent to AllSPFRouters or AllDRouters 178 * or to the address of the interface itself. 179 * AllDRouters is only valid for DR and BDR but this is checked later. 180 */ 181 inet_pton(AF_INET6, AllSPFRouters, &addr); 182 183 if (!IN6_ARE_ADDR_EQUAL(&dest, &addr)) { 184 inet_pton(AF_INET6, AllDRouters, &addr); 185 if (!IN6_ARE_ADDR_EQUAL(&dest, &addr)) { 186 if (!IN6_ARE_ADDR_EQUAL(&dest, &iface->addr)) { 187 log_debug("recv_packet: packet sent to wrong " 188 "address %s, interface %s", 189 log_in6addr(&dest), iface->name); 190 return; 191 } 192 } 193 } 194 195 len = (u_int16_t)r; 196 /* OSPF header sanity checks */ 197 if (len < sizeof(*ospf_hdr)) { 198 log_debug("recv_packet: bad packet size"); 199 return; 200 } 201 ospf_hdr = (struct ospf_hdr *)buf; 202 203 if ((l = ospf_hdr_sanity_check(ospf_hdr, len, iface, &dest)) == -1) 204 return; 205 206 nbr = nbr_find_id(iface, ospf_hdr->rtr_id); 207 if (ospf_hdr->type != PACKET_TYPE_HELLO && nbr == NULL) { 208 log_debug("recv_packet: unknown neighbor ID"); 209 return; 210 } 211 212 buf += sizeof(*ospf_hdr); 213 len = l - sizeof(*ospf_hdr); 214 215 /* switch OSPF packet type */ 216 switch (ospf_hdr->type) { 217 case PACKET_TYPE_HELLO: 218 inet_pton(AF_INET6, AllDRouters, &addr); 219 if (IN6_ARE_ADDR_EQUAL(&dest, &addr)) { 220 log_debug("recv_packet: invalid destination IP " 221 "address"); 222 break; 223 } 224 225 recv_hello(iface, &src.sin6_addr, ospf_hdr->rtr_id, buf, len); 226 break; 227 case PACKET_TYPE_DD: 228 recv_db_description(nbr, buf, len); 229 break; 230 case PACKET_TYPE_LS_REQUEST: 231 recv_ls_req(nbr, buf, len); 232 break; 233 case PACKET_TYPE_LS_UPDATE: 234 recv_ls_update(nbr, buf, len); 235 break; 236 case PACKET_TYPE_LS_ACK: 237 recv_ls_ack(nbr, buf, len); 238 break; 239 default: 240 log_debug("recv_packet: unknown OSPF packet type, interface %s", 241 iface->name); 242 } 243 } 244 245 int 246 ospf_hdr_sanity_check(struct ospf_hdr *ospf_hdr, u_int16_t len, 247 const struct iface *iface, struct in6_addr *dst) 248 { 249 struct in6_addr addr; 250 struct in_addr id; 251 252 if (ospf_hdr->version != OSPF6_VERSION) { 253 log_debug("recv_packet: invalid OSPF version %d", 254 ospf_hdr->version); 255 return (-1); 256 } 257 258 if (ntohs(ospf_hdr->len) > len || 259 len <= sizeof(struct ospf_hdr)) { 260 log_debug("recv_packet: invalid OSPF packet length %d", 261 ntohs(ospf_hdr->len)); 262 return (-1); 263 } 264 265 if (iface->type != IF_TYPE_VIRTUALLINK) { 266 if (ospf_hdr->area_id != iface->area_id.s_addr) { 267 id.s_addr = ospf_hdr->area_id; 268 log_debug("recv_packet: invalid area ID %s, " 269 "interface %s", inet_ntoa(id), iface->name); 270 return (-1); 271 } 272 } else { 273 if (ospf_hdr->area_id != 0) { 274 id.s_addr = ospf_hdr->area_id; 275 log_debug("recv_packet: invalid area ID %s, " 276 "interface %s", inet_ntoa(id), iface->name); 277 return (-1); 278 } 279 } 280 281 if (iface->type == IF_TYPE_BROADCAST || iface->type == IF_TYPE_NBMA) { 282 if (inet_pton(AF_INET6, AllDRouters, &addr) == 0) 283 fatalx("recv_packet: inet_pton"); 284 if (IN6_ARE_ADDR_EQUAL(dst, &addr) && 285 (iface->state & IF_STA_DRORBDR) == 0) { 286 log_debug("recv_packet: invalid destination IP in " 287 "state %s, interface %s", 288 if_state_name(iface->state), iface->name); 289 return (-1); 290 } 291 } 292 293 return (ntohs(ospf_hdr->len)); 294 } 295 296 struct iface * 297 find_iface(struct ospfd_conf *xconf, unsigned int ifindex, struct in6_addr *src) 298 { 299 struct area *area; 300 struct iface *iface, *match = NULL; 301 302 /* 303 * Returned interface needs to be active. 304 * Virtual-Links have higher precedence so the full interface 305 * list needs to be scanned for possible matches. 306 */ 307 LIST_FOREACH(area, &xconf->area_list, entry) { 308 LIST_FOREACH(iface, &area->iface_list, entry) { 309 switch (iface->type) { 310 case IF_TYPE_VIRTUALLINK: 311 if (IN6_ARE_ADDR_EQUAL(src, &iface->dst) && 312 !(iface->cflags & F_IFACE_PASSIVE)) 313 return (iface); 314 break; 315 default: 316 if (ifindex == iface->ifindex && 317 !(iface->cflags & F_IFACE_PASSIVE)) 318 match = iface; 319 break; 320 } 321 } 322 } 323 324 return (match); 325 } 326