1 /* $OpenBSD: packet.c,v 1.19 2021/01/19 09:43:40 claudio 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 86 /* setup sockaddr */ 87 bzero(&sa6, sizeof(sa6)); 88 sa6.sin6_family = AF_INET6; 89 sa6.sin6_len = sizeof(sa6); 90 sa6.sin6_addr = *dst; 91 92 /* don't we all love link local scope and all the needed hacks for it */ 93 if (IN6_IS_ADDR_LINKLOCAL(dst) || IN6_IS_ADDR_MC_LINKLOCAL(dst)) 94 sa6.sin6_scope_id = iface->ifindex; 95 96 /* set outgoing interface for multicast traffic */ 97 if (IN6_IS_ADDR_MULTICAST(dst)) 98 if (if_set_mcast(iface) == -1) { 99 log_warn("send_packet: error setting multicast " 100 "interface, %s", iface->name); 101 return (-1); 102 } 103 104 if (sendto(iface->fd, buf->buf, ibuf_size(buf), 0, 105 (struct sockaddr *)&sa6, sizeof(sa6)) == -1) { 106 log_warn("send_packet: error sending packet on interface %s", 107 iface->name); 108 return (-1); 109 } 110 111 return (0); 112 } 113 114 void 115 recv_packet(int fd, short event, void *bula) 116 { 117 static char pkt_ptr[READ_BUF_SIZE]; 118 union { 119 struct cmsghdr hdr; 120 char buf[CMSG_SPACE(sizeof(struct in6_pktinfo))]; 121 } cmsgbuf; 122 struct msghdr msg; 123 struct iovec iov; 124 struct in6_addr addr, dest; 125 struct sockaddr_in6 src; 126 struct ospfd_conf *xconf = bula; 127 struct ospf_hdr *ospf_hdr; 128 struct iface *iface; 129 struct nbr *nbr = NULL; 130 char *buf; 131 struct cmsghdr *cmsg; 132 ssize_t r; 133 u_int16_t len; 134 int l; 135 unsigned int ifindex = 0; 136 137 if (event != EV_READ) 138 return; 139 140 /* setup buffer */ 141 bzero(&msg, sizeof(msg)); 142 iov.iov_base = buf = pkt_ptr; 143 iov.iov_len = READ_BUF_SIZE; 144 msg.msg_name = &src; 145 msg.msg_namelen = sizeof(src); 146 msg.msg_iov = &iov; 147 msg.msg_iovlen = 1; 148 msg.msg_control = &cmsgbuf.buf; 149 msg.msg_controllen = sizeof(cmsgbuf.buf); 150 151 if ((r = recvmsg(fd, &msg, 0)) == -1) { 152 if (errno != EAGAIN && errno != EINTR) 153 log_debug("recv_packet: read error: %s", 154 strerror(errno)); 155 return; 156 } 157 for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; 158 cmsg = CMSG_NXTHDR(&msg, cmsg)) { 159 if (cmsg->cmsg_level == IPPROTO_IPV6 && 160 cmsg->cmsg_type == IPV6_PKTINFO) { 161 ifindex = ((struct in6_pktinfo *) 162 CMSG_DATA(cmsg))->ipi6_ifindex; 163 dest = ((struct in6_pktinfo *) 164 CMSG_DATA(cmsg))->ipi6_addr; 165 break; 166 } 167 } 168 169 /* find a matching interface */ 170 if ((iface = find_iface(xconf, ifindex, &src.sin6_addr)) == NULL) { 171 /* XXX add a counter here */ 172 return; 173 } 174 /* 175 * Packet needs to be sent to AllSPFRouters or AllDRouters 176 * or to the address of the interface itself. 177 * AllDRouters is only valid for DR and BDR but this is checked later. 178 */ 179 inet_pton(AF_INET6, AllSPFRouters, &addr); 180 if (!IN6_ARE_ADDR_EQUAL(&dest, &addr)) { 181 inet_pton(AF_INET6, AllDRouters, &addr); 182 if (!IN6_ARE_ADDR_EQUAL(&dest, &addr)) { 183 struct iface_addr *ia; 184 185 TAILQ_FOREACH(ia, &iface->ifa_list, entry) { 186 if (IN6_ARE_ADDR_EQUAL(&dest, &ia->addr)) 187 break; 188 } 189 if (ia == NULL) { 190 log_debug("recv_packet: packet sent to wrong " 191 "address %s, interface %s", 192 log_in6addr(&dest), iface->name); 193 return; 194 } 195 } 196 } 197 198 len = (u_int16_t)r; 199 /* OSPF header sanity checks */ 200 if (len < sizeof(*ospf_hdr)) { 201 log_debug("recv_packet: bad packet size"); 202 return; 203 } 204 ospf_hdr = (struct ospf_hdr *)buf; 205 206 if ((l = ospf_hdr_sanity_check(ospf_hdr, len, iface, &dest)) == -1) 207 return; 208 209 nbr = nbr_find_id(iface, ospf_hdr->rtr_id); 210 if (ospf_hdr->type != PACKET_TYPE_HELLO && nbr == NULL) { 211 log_debug("recv_packet: unknown neighbor ID"); 212 return; 213 } 214 215 buf += sizeof(*ospf_hdr); 216 len = l - sizeof(*ospf_hdr); 217 218 /* switch OSPF packet type */ 219 switch (ospf_hdr->type) { 220 case PACKET_TYPE_HELLO: 221 inet_pton(AF_INET6, AllDRouters, &addr); 222 if (IN6_ARE_ADDR_EQUAL(&dest, &addr)) { 223 log_debug("recv_packet: invalid destination IP " 224 "address"); 225 break; 226 } 227 228 recv_hello(iface, &src.sin6_addr, ospf_hdr->rtr_id, buf, len); 229 break; 230 case PACKET_TYPE_DD: 231 recv_db_description(nbr, buf, len); 232 break; 233 case PACKET_TYPE_LS_REQUEST: 234 recv_ls_req(nbr, buf, len); 235 break; 236 case PACKET_TYPE_LS_UPDATE: 237 recv_ls_update(nbr, buf, len); 238 break; 239 case PACKET_TYPE_LS_ACK: 240 recv_ls_ack(nbr, buf, len); 241 break; 242 default: 243 log_debug("recv_packet: unknown OSPF packet type, interface %s", 244 iface->name); 245 } 246 } 247 248 int 249 ospf_hdr_sanity_check(struct ospf_hdr *ospf_hdr, u_int16_t len, 250 const struct iface *iface, struct in6_addr *dst) 251 { 252 struct in6_addr addr; 253 struct in_addr id; 254 255 if (ospf_hdr->version != OSPF6_VERSION) { 256 log_debug("recv_packet: invalid OSPF version %d", 257 ospf_hdr->version); 258 return (-1); 259 } 260 261 if (ntohs(ospf_hdr->len) > len || 262 len <= sizeof(struct ospf_hdr)) { 263 log_debug("recv_packet: invalid OSPF packet length %d", 264 ntohs(ospf_hdr->len)); 265 return (-1); 266 } 267 268 if (iface->type != IF_TYPE_VIRTUALLINK) { 269 if (ospf_hdr->area_id != iface->area->id.s_addr) { 270 id.s_addr = ospf_hdr->area_id; 271 log_debug("recv_packet: invalid area ID %s, " 272 "interface %s", inet_ntoa(id), iface->name); 273 return (-1); 274 } 275 } else { 276 if (ospf_hdr->area_id != 0) { 277 id.s_addr = ospf_hdr->area_id; 278 log_debug("recv_packet: invalid area ID %s, " 279 "interface %s", inet_ntoa(id), iface->name); 280 return (-1); 281 } 282 } 283 284 if (iface->type == IF_TYPE_BROADCAST || iface->type == IF_TYPE_NBMA) { 285 if (inet_pton(AF_INET6, AllDRouters, &addr) == 0) 286 fatalx("recv_packet: inet_pton"); 287 if (IN6_ARE_ADDR_EQUAL(dst, &addr) && 288 (iface->state & IF_STA_DRORBDR) == 0) { 289 log_debug("recv_packet: invalid destination IP in " 290 "state %s, interface %s", 291 if_state_name(iface->state), iface->name); 292 return (-1); 293 } 294 } 295 296 return (ntohs(ospf_hdr->len)); 297 } 298 299 struct iface * 300 find_iface(struct ospfd_conf *xconf, unsigned int ifindex, struct in6_addr *src) 301 { 302 struct area *area; 303 struct iface *iface, *match = NULL; 304 305 /* 306 * Returned interface needs to be active. 307 * Virtual-Links have higher precedence so the full interface 308 * list needs to be scanned for possible matches. 309 */ 310 LIST_FOREACH(area, &xconf->area_list, entry) { 311 LIST_FOREACH(iface, &area->iface_list, entry) { 312 switch (iface->type) { 313 case IF_TYPE_VIRTUALLINK: 314 if (IN6_ARE_ADDR_EQUAL(src, &iface->dst) && 315 !(iface->cflags & F_IFACE_PASSIVE)) 316 return (iface); 317 break; 318 default: 319 if (ifindex == iface->ifindex && 320 !(iface->cflags & F_IFACE_PASSIVE)) 321 match = iface; 322 break; 323 } 324 } 325 } 326 327 return (match); 328 } 329