1 /* $OpenBSD: packet.c,v 1.1 2006/06/01 14:12:20 norby Exp $ */ 2 3 /* 4 * Copyright (c) 2004, 2005, 2006 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/time.h> 22 23 #include <netinet/in.h> 24 #include <netinet/in_systm.h> 25 #include <netinet/ip.h> 26 #include <netinet/ip_mroute.h> 27 #include <arpa/inet.h> 28 29 #include <errno.h> 30 #include <event.h> 31 #include <stdlib.h> 32 #include <strings.h> 33 34 #include "igmp.h" 35 #include "dvmrpd.h" 36 #include "dvmrp.h" 37 #include "log.h" 38 #include "dvmrpe.h" 39 40 int ip_hdr_sanity_check(const struct ip *, u_int16_t); 41 int dvmrp_hdr_sanity_check(const struct ip *, struct dvmrp_hdr *, 42 u_int16_t, const struct iface *); 43 struct iface *find_iface(struct dvmrpd_conf *, struct in_addr); 44 45 extern struct dvmrpd_conf *deconf; 46 47 int 48 gen_dvmrp_hdr(struct buf *buf, struct iface *iface, u_int8_t code) 49 { 50 struct dvmrp_hdr dvmrp_hdr; 51 52 bzero(&dvmrp_hdr, sizeof(dvmrp_hdr)); 53 dvmrp_hdr.type = PKT_TYPE_DVMRP; 54 dvmrp_hdr.code = code; 55 dvmrp_hdr.chksum = 0; /* updated later */ 56 dvmrp_hdr.capabilities = DVMRP_CAP_DEFAULT; /* XXX update */ 57 dvmrp_hdr.minor_version = DVMRP_MINOR_VERSION; 58 dvmrp_hdr.major_version = DVMRP_MAJOR_VERSION; 59 60 return (buf_add(buf, &dvmrp_hdr, sizeof(dvmrp_hdr))); 61 } 62 63 /* send and receive packets */ 64 int 65 send_packet(struct iface *iface, void *pkt, size_t len, struct sockaddr_in *dst) 66 { 67 if (iface->passive) { 68 log_warnx("send_packet: cannot send packet on passive " 69 "interface %s", iface->name); 70 return (-1); 71 } 72 73 /* set outgoing interface for multicast traffic */ 74 if (IN_MULTICAST(ntohl(dst->sin_addr.s_addr))) 75 if (if_set_mcast(iface) == -1) { 76 log_warn("send_packet: error setting multicast " 77 "interface, %s", iface->name); 78 return (-1); 79 } 80 81 if (sendto(iface->fd, pkt, len, 0, 82 (struct sockaddr *)dst, sizeof(*dst)) == -1 ) { 83 log_warn("send_packet: error sending packet on interface %s", 84 iface->name); 85 return (-1); 86 } 87 88 return (0); 89 } 90 91 void 92 recv_packet(int fd, short event, void *bula) 93 { 94 struct dvmrpd_conf *xconf = bula; 95 struct ip ip_hdr; 96 struct dvmrp_hdr *dvmrp_hdr; 97 struct iface *iface; 98 struct nbr *nbr = NULL; 99 struct in_addr addr; 100 char *buf; 101 ssize_t r; 102 u_int16_t len; 103 int l; 104 105 if (event != EV_READ) 106 return; 107 108 /* setup buffer */ 109 buf = pkt_ptr; 110 111 if ((r = recvfrom(fd, buf, READ_BUF_SIZE, 0, NULL, NULL)) == -1) { 112 if (errno != EAGAIN && errno != EINTR) 113 log_debug("recv_packet: error receiving packet"); 114 return; 115 } 116 117 len = (u_int16_t)r; 118 119 /* IP header sanity checks */ 120 if (len < sizeof(ip_hdr)) { 121 log_warnx("recv_packet: bad packet size"); 122 return; 123 } 124 125 memcpy(&ip_hdr, buf, sizeof(ip_hdr)); 126 if ((l = ip_hdr_sanity_check(&ip_hdr, len)) == -1) 127 return; 128 buf += l; 129 len -= l; 130 131 /* find a matching interface */ 132 if ((iface = find_iface(xconf, ip_hdr.ip_src)) == NULL) { 133 log_debug("recv_packet: cannot find valid interface, ip src %s", 134 inet_ntoa(ip_hdr.ip_src)); 135 return; 136 } 137 138 /* header sanity checks */ 139 if (len < sizeof(*dvmrp_hdr)) { 140 log_warnx("recv_packet: bad packet size"); 141 return; 142 } 143 dvmrp_hdr = (struct dvmrp_hdr *)buf; 144 145 switch (dvmrp_hdr->type) { 146 /* DVMRP */ 147 case PKT_TYPE_DVMRP: 148 if ((l = dvmrp_hdr_sanity_check(&ip_hdr, dvmrp_hdr, len, 149 iface)) == -1) 150 return; 151 152 /* 153 * mrouted compat 154 * 155 * Old mrouted versions, send route reports before establishing 156 * 2-WAY neighbor relationships. 157 */ 158 if ((nbr_find_ip(iface, ip_hdr.ip_src.s_addr) == NULL) && 159 (dvmrp_hdr->code == DVMRP_CODE_REPORT)) { 160 log_debug("recv_packet: route report from neighbor" 161 " ID %s, compat", inet_ntoa(ip_hdr.ip_src)); 162 nbr = nbr_new(ip_hdr.ip_src.s_addr, iface, 0); 163 nbr_fsm(nbr, NBR_EVT_PROBE_RCVD); 164 nbr->compat = 1; 165 nbr->addr = ip_hdr.ip_src; 166 } 167 168 if ((dvmrp_hdr->type == PKT_TYPE_DVMRP) && 169 (dvmrp_hdr->code != DVMRP_CODE_PROBE)) 170 /* find neighbor */ 171 if ((nbr = nbr_find_ip(iface, ip_hdr.ip_src.s_addr)) 172 == NULL) { 173 log_debug("recv_packet: unknown neighbor ID"); 174 return; 175 } 176 177 buf += sizeof(*dvmrp_hdr); 178 len = l - sizeof(*dvmrp_hdr); 179 180 inet_aton(AllDVMRPRouters, &addr); 181 if ((ip_hdr.ip_dst.s_addr != addr.s_addr) && 182 (ip_hdr.ip_dst.s_addr != iface->addr.s_addr)) { 183 log_debug("recv_packet: interface %s, invalid" 184 " destination IP address %s", iface->name, 185 inet_ntoa(ip_hdr.ip_dst)); 186 break; 187 } 188 189 switch (dvmrp_hdr->code) { 190 case DVMRP_CODE_PROBE: 191 recv_probe(iface, ip_hdr.ip_src, ip_hdr.ip_src.s_addr, 192 dvmrp_hdr->capabilities, buf, len); 193 break; 194 case DVMRP_CODE_REPORT: 195 recv_report(nbr, buf, len); 196 break; 197 case DVMRP_CODE_ASK_NBRS2: 198 recv_ask_nbrs2(nbr, buf,len); 199 break; 200 case DVMRP_CODE_NBRS2: 201 recv_nbrs2(nbr, buf,len); 202 break; 203 case DVMRP_CODE_PRUNE: 204 recv_prune(nbr, buf, len); 205 break; 206 case DVMRP_CODE_GRAFT: 207 recv_graft(nbr, buf,len); 208 break; 209 case DVMRP_CODE_GRAFT_ACK: 210 recv_graft_ack(nbr, buf,len); 211 break; 212 default: 213 log_debug("recv_packet: unknown DVMRP packet type, " 214 "interface %s", iface->name); 215 } 216 break; 217 /* IGMP */ 218 case PKT_TYPE_MEMBER_QUERY: 219 recv_igmp_query(iface, ip_hdr.ip_src, buf, len); 220 break; 221 case PKT_TYPE_MEMBER_REPORTv1: 222 case PKT_TYPE_MEMBER_REPORTv2: 223 recv_igmp_report(iface, ip_hdr.ip_src, buf, len, 224 dvmrp_hdr->type); 225 break; 226 case PKT_TYPE_LEAVE_GROUPv2: 227 recv_igmp_leave(iface, ip_hdr.ip_src, buf, len); 228 break; 229 default: 230 log_debug("recv_packet: unknown IGMP packet type, interface %s", 231 iface->name); 232 } 233 } 234 235 int 236 ip_hdr_sanity_check(const struct ip *ip_hdr, u_int16_t len) 237 { 238 if (ntohs(ip_hdr->ip_len) != len) { 239 log_debug("recv_packet: invalid IP packet length %u", 240 ntohs(ip_hdr->ip_len)); 241 return (-1); 242 } 243 244 if (ip_hdr->ip_p != IPPROTO_IGMP) 245 /* this is enforced by the socket itself */ 246 fatalx("recv_packet: invalid IP proto"); 247 248 return (ip_hdr->ip_hl << 2); 249 } 250 251 int 252 dvmrp_hdr_sanity_check(const struct ip *ip_hdr, struct dvmrp_hdr *dvmrp_hdr, 253 u_int16_t len, const struct iface *iface) 254 { 255 /* we only support DVMRPv3 */ 256 if (dvmrp_hdr->major_version != DVMRP_MAJOR_VERSION) { 257 log_debug("recv_packet: invalid DVMRP version"); 258 return (-1); 259 } 260 261 /* XXX enforce minor version as well, but not yet */ 262 263 /* XXX chksum */ 264 265 return (len); 266 } 267 268 struct iface * 269 find_iface(struct dvmrpd_conf *xconf, struct in_addr src) 270 { 271 struct iface *iface = NULL; 272 273 /* returned interface needs to be active */ 274 LIST_FOREACH(iface, &xconf->iface_list, entry) { 275 if (iface->fd > 0 && 276 (iface->type == IF_TYPE_POINTOPOINT) && 277 (iface->dst.s_addr == src.s_addr) && 278 !iface->passive) 279 return (iface); 280 281 if (iface->fd > 0 && (iface->addr.s_addr & 282 iface->mask.s_addr) == (src.s_addr & 283 iface->mask.s_addr) && !iface->passive) 284 return (iface); 285 } 286 287 return (NULL); 288 } 289