1 /* $OpenBSD: packet.c,v 1.17 2019/12/23 07:33:49 denis 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/ip.h> 25 #include <netinet/ip6.h> 26 #include <arpa/inet.h> 27 28 #include <errno.h> 29 #include <event.h> 30 #include <limits.h> 31 #include <stdlib.h> 32 #include <string.h> 33 34 #include "ospf6d.h" 35 #include "ospf6.h" 36 #include "log.h" 37 #include "ospfe.h" 38 39 int ip_hdr_sanity_check(const struct ip6_hdr *, u_int16_t); 40 int ospf_hdr_sanity_check(struct ospf_hdr *, u_int16_t, 41 const struct iface *, struct in6_addr *); 42 struct iface *find_iface(struct ospfd_conf *, unsigned int, 43 struct in6_addr *); 44 45 int 46 gen_ospf_hdr(struct ibuf *buf, struct iface *iface, u_int8_t type) 47 { 48 struct ospf_hdr ospf_hdr; 49 50 bzero(&ospf_hdr, sizeof(ospf_hdr)); 51 ospf_hdr.version = OSPF6_VERSION; 52 ospf_hdr.type = type; 53 ospf_hdr.rtr_id = ospfe_router_id(); 54 if (iface->type != IF_TYPE_VIRTUALLINK) 55 ospf_hdr.area_id = iface->area->id.s_addr; 56 ospf_hdr.instance = DEFAULT_INSTANCE_ID; 57 ospf_hdr.zero = 0; /* must be zero */ 58 59 return (ibuf_add(buf, &ospf_hdr, sizeof(ospf_hdr))); 60 } 61 62 int 63 upd_ospf_hdr(struct ibuf *buf, struct iface *iface) 64 { 65 struct ospf_hdr *ospf_hdr; 66 67 if ((ospf_hdr = ibuf_seek(buf, 0, sizeof(*ospf_hdr))) == NULL) 68 fatalx("upd_ospf_hdr: buf_seek failed"); 69 70 /* update length */ 71 if (buf->wpos > USHRT_MAX) 72 fatalx("upd_ospf_hdr: resulting ospf packet too big"); 73 ospf_hdr->len = htons((u_int16_t)buf->wpos); 74 ospf_hdr->chksum = 0; /* calculated via IPV6_CHECKSUM */ 75 76 return (0); 77 } 78 79 /* send and receive packets */ 80 int 81 send_packet(struct iface *iface, struct ibuf *buf, 82 struct in6_addr *dst) 83 { 84 struct sockaddr_in6 sa6; 85 struct msghdr msg; 86 struct iovec iov[1]; 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 bzero(&msg, sizeof(msg)); 108 msg.msg_name = &sa6; 109 msg.msg_namelen = sizeof(sa6); 110 iov[0].iov_base = buf->buf; 111 iov[0].iov_len = ibuf_size(buf); 112 msg.msg_iov = iov; 113 msg.msg_iovlen = 1; 114 115 if (sendmsg(iface->fd, &msg, 0) == -1) { 116 log_warn("send_packet: error sending packet on interface %s", 117 iface->name); 118 return (-1); 119 } 120 121 return (0); 122 } 123 124 void 125 recv_packet(int fd, short event, void *bula) 126 { 127 union { 128 struct cmsghdr hdr; 129 char buf[CMSG_SPACE(sizeof(struct in6_pktinfo))]; 130 } cmsgbuf; 131 struct msghdr msg; 132 struct iovec iov; 133 struct in6_addr addr, dest; 134 struct sockaddr_in6 src; 135 struct ospfd_conf *xconf = bula; 136 struct ospf_hdr *ospf_hdr; 137 struct iface *iface; 138 struct nbr *nbr = NULL; 139 char *buf; 140 struct cmsghdr *cmsg; 141 ssize_t r; 142 u_int16_t len; 143 int l; 144 unsigned int ifindex = 0; 145 146 if (event != EV_READ) 147 return; 148 149 /* setup buffer */ 150 bzero(&msg, sizeof(msg)); 151 iov.iov_base = buf = pkt_ptr; 152 iov.iov_len = READ_BUF_SIZE; 153 msg.msg_name = &src; 154 msg.msg_namelen = sizeof(src); 155 msg.msg_iov = &iov; 156 msg.msg_iovlen = 1; 157 msg.msg_control = &cmsgbuf.buf; 158 msg.msg_controllen = sizeof(cmsgbuf.buf); 159 160 if ((r = recvmsg(fd, &msg, 0)) == -1) { 161 if (errno != EAGAIN && errno != EINTR) 162 log_debug("recv_packet: read error: %s", 163 strerror(errno)); 164 return; 165 } 166 for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; 167 cmsg = CMSG_NXTHDR(&msg, cmsg)) { 168 if (cmsg->cmsg_level == IPPROTO_IPV6 && 169 cmsg->cmsg_type == IPV6_PKTINFO) { 170 ifindex = ((struct in6_pktinfo *) 171 CMSG_DATA(cmsg))->ipi6_ifindex; 172 dest = ((struct in6_pktinfo *) 173 CMSG_DATA(cmsg))->ipi6_addr; 174 break; 175 } 176 } 177 178 /* find a matching interface */ 179 if ((iface = find_iface(xconf, ifindex, &src.sin6_addr)) == NULL) { 180 /* XXX add a counter here */ 181 return; 182 } 183 /* 184 * Packet needs to be sent to AllSPFRouters or AllDRouters 185 * or to the address of the interface itself. 186 * AllDRouters is only valid for DR and BDR but this is checked later. 187 */ 188 inet_pton(AF_INET6, AllSPFRouters, &addr); 189 190 if (!IN6_ARE_ADDR_EQUAL(&dest, &addr)) { 191 inet_pton(AF_INET6, AllDRouters, &addr); 192 if (!IN6_ARE_ADDR_EQUAL(&dest, &addr)) { 193 if (!IN6_ARE_ADDR_EQUAL(&dest, &iface->addr)) { 194 log_debug("recv_packet: packet sent to wrong " 195 "address %s, interface %s", 196 log_in6addr(&dest), iface->name); 197 return; 198 } 199 } 200 } 201 202 len = (u_int16_t)r; 203 /* OSPF header sanity checks */ 204 if (len < sizeof(*ospf_hdr)) { 205 log_debug("recv_packet: bad packet size"); 206 return; 207 } 208 ospf_hdr = (struct ospf_hdr *)buf; 209 210 if ((l = ospf_hdr_sanity_check(ospf_hdr, len, iface, &dest)) == -1) 211 return; 212 213 nbr = nbr_find_id(iface, ospf_hdr->rtr_id); 214 if (ospf_hdr->type != PACKET_TYPE_HELLO && nbr == NULL) { 215 log_debug("recv_packet: unknown neighbor ID"); 216 return; 217 } 218 219 buf += sizeof(*ospf_hdr); 220 len = l - sizeof(*ospf_hdr); 221 222 /* switch OSPF packet type */ 223 switch (ospf_hdr->type) { 224 case PACKET_TYPE_HELLO: 225 inet_pton(AF_INET6, AllDRouters, &addr); 226 if (IN6_ARE_ADDR_EQUAL(&dest, &addr)) { 227 log_debug("recv_packet: invalid destination IP " 228 "address"); 229 break; 230 } 231 232 recv_hello(iface, &src.sin6_addr, ospf_hdr->rtr_id, buf, len); 233 break; 234 case PACKET_TYPE_DD: 235 recv_db_description(nbr, buf, len); 236 break; 237 case PACKET_TYPE_LS_REQUEST: 238 recv_ls_req(nbr, buf, len); 239 break; 240 case PACKET_TYPE_LS_UPDATE: 241 recv_ls_update(nbr, buf, len); 242 break; 243 case PACKET_TYPE_LS_ACK: 244 recv_ls_ack(nbr, buf, len); 245 break; 246 default: 247 log_debug("recv_packet: unknown OSPF packet type, interface %s", 248 iface->name); 249 } 250 } 251 252 int 253 ospf_hdr_sanity_check(struct ospf_hdr *ospf_hdr, u_int16_t len, 254 const struct iface *iface, struct in6_addr *dst) 255 { 256 struct in6_addr addr; 257 struct in_addr id; 258 259 if (ospf_hdr->version != OSPF6_VERSION) { 260 log_debug("recv_packet: invalid OSPF version %d", 261 ospf_hdr->version); 262 return (-1); 263 } 264 265 if (ntohs(ospf_hdr->len) > len || 266 len <= sizeof(struct ospf_hdr)) { 267 log_debug("recv_packet: invalid OSPF packet length %d", 268 ntohs(ospf_hdr->len)); 269 return (-1); 270 } 271 272 if (iface->type != IF_TYPE_VIRTUALLINK) { 273 if (ospf_hdr->area_id != iface->area->id.s_addr) { 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 } else { 280 if (ospf_hdr->area_id != 0) { 281 id.s_addr = ospf_hdr->area_id; 282 log_debug("recv_packet: invalid area ID %s, " 283 "interface %s", inet_ntoa(id), iface->name); 284 return (-1); 285 } 286 } 287 288 if (iface->type == IF_TYPE_BROADCAST || iface->type == IF_TYPE_NBMA) { 289 if (inet_pton(AF_INET6, AllDRouters, &addr) == 0) 290 fatalx("recv_packet: inet_pton"); 291 if (IN6_ARE_ADDR_EQUAL(dst, &addr) && 292 (iface->state & IF_STA_DRORBDR) == 0) { 293 log_debug("recv_packet: invalid destination IP in " 294 "state %s, interface %s", 295 if_state_name(iface->state), iface->name); 296 return (-1); 297 } 298 } 299 300 return (ntohs(ospf_hdr->len)); 301 } 302 303 struct iface * 304 find_iface(struct ospfd_conf *xconf, unsigned int ifindex, struct in6_addr *src) 305 { 306 struct area *area; 307 struct iface *iface, *match = NULL; 308 309 /* 310 * Returned interface needs to be active. 311 * Virtual-Links have higher precedence so the full interface 312 * list needs to be scanned for possible matches. 313 */ 314 LIST_FOREACH(area, &xconf->area_list, entry) { 315 LIST_FOREACH(iface, &area->iface_list, entry) { 316 switch (iface->type) { 317 case IF_TYPE_VIRTUALLINK: 318 if (IN6_ARE_ADDR_EQUAL(src, &iface->dst) && 319 !(iface->cflags & F_IFACE_PASSIVE)) 320 return (iface); 321 break; 322 default: 323 if (ifindex == iface->ifindex && 324 !(iface->cflags & F_IFACE_PASSIVE)) 325 match = iface; 326 break; 327 } 328 } 329 } 330 331 return (match); 332 } 333