1 /* $OpenBSD: packet.c,v 1.5 2015/12/07 19:14:49 mmcc 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/ip.h> 25 #include <netinet/ip_mroute.h> 26 #include <arpa/inet.h> 27 28 #include <errno.h> 29 #include <event.h> 30 #include <stdlib.h> 31 #include <string.h> 32 33 #include "igmp.h" 34 #include "dvmrpd.h" 35 #include "dvmrp.h" 36 #include "log.h" 37 #include "dvmrpe.h" 38 39 int ip_hdr_sanity_check(const struct ip *, u_int16_t); 40 int dvmrp_hdr_sanity_check(const struct ip *, struct dvmrp_hdr *, 41 u_int16_t, const struct iface *); 42 struct iface *find_iface(struct dvmrpd_conf *, struct in_addr); 43 44 extern struct dvmrpd_conf *deconf; 45 46 int 47 gen_dvmrp_hdr(struct ibuf *buf, struct iface *iface, u_int8_t code) 48 { 49 struct dvmrp_hdr dvmrp_hdr; 50 51 memset(&dvmrp_hdr, 0, sizeof(dvmrp_hdr)); 52 dvmrp_hdr.type = PKT_TYPE_DVMRP; 53 dvmrp_hdr.code = code; 54 dvmrp_hdr.chksum = 0; /* updated later */ 55 dvmrp_hdr.capabilities = DVMRP_CAP_DEFAULT; /* XXX update */ 56 dvmrp_hdr.minor_version = DVMRP_MINOR_VERSION; 57 dvmrp_hdr.major_version = DVMRP_MAJOR_VERSION; 58 59 return (ibuf_add(buf, &dvmrp_hdr, sizeof(dvmrp_hdr))); 60 } 61 62 /* send and receive packets */ 63 int 64 send_packet(struct iface *iface, void *pkt, size_t len, struct sockaddr_in *dst) 65 { 66 if (iface->passive) { 67 log_warnx("send_packet: cannot send packet on passive " 68 "interface %s", iface->name); 69 return (-1); 70 } 71 72 /* set outgoing interface for multicast traffic */ 73 if (IN_MULTICAST(ntohl(dst->sin_addr.s_addr))) 74 if (if_set_mcast(iface) == -1) { 75 log_warn("send_packet: error setting multicast " 76 "interface, %s", iface->name); 77 return (-1); 78 } 79 80 if (sendto(iface->fd, pkt, len, 0, 81 (struct sockaddr *)dst, sizeof(*dst)) == -1 ) { 82 log_warn("send_packet: error sending packet on interface %s", 83 iface->name); 84 return (-1); 85 } 86 87 return (0); 88 } 89 90 void 91 recv_packet(int fd, short event, void *bula) 92 { 93 struct dvmrpd_conf *xconf = bula; 94 struct ip ip_hdr; 95 struct dvmrp_hdr *dvmrp_hdr; 96 struct iface *iface; 97 struct nbr *nbr = NULL; 98 struct in_addr addr; 99 char *buf; 100 ssize_t r; 101 u_int16_t len; 102 int l; 103 104 if (event != EV_READ) 105 return; 106 107 /* setup buffer */ 108 buf = pkt_ptr; 109 110 if ((r = recvfrom(fd, buf, IBUF_READ_SIZE, 0, NULL, NULL)) == -1) { 111 if (errno != EAGAIN && errno != EINTR) 112 log_debug("recv_packet: error receiving packet"); 113 return; 114 } 115 116 len = (u_int16_t)r; 117 118 /* IP header sanity checks */ 119 if (len < sizeof(ip_hdr)) { 120 log_warnx("recv_packet: bad packet size"); 121 return; 122 } 123 124 memcpy(&ip_hdr, buf, sizeof(ip_hdr)); 125 if ((l = ip_hdr_sanity_check(&ip_hdr, len)) == -1) 126 return; 127 buf += l; 128 len -= l; 129 130 /* find a matching interface */ 131 if ((iface = find_iface(xconf, ip_hdr.ip_src)) == NULL) { 132 log_debug("recv_packet: cannot find valid interface, ip src %s", 133 inet_ntoa(ip_hdr.ip_src)); 134 return; 135 } 136 137 /* header sanity checks */ 138 if (len < sizeof(*dvmrp_hdr)) { 139 log_warnx("recv_packet: bad packet size"); 140 return; 141 } 142 dvmrp_hdr = (struct dvmrp_hdr *)buf; 143 144 switch (dvmrp_hdr->type) { 145 /* DVMRP */ 146 case PKT_TYPE_DVMRP: 147 if ((l = dvmrp_hdr_sanity_check(&ip_hdr, dvmrp_hdr, len, 148 iface)) == -1) 149 return; 150 151 /* 152 * mrouted compat 153 * 154 * Old mrouted versions, send route reports before establishing 155 * 2-WAY neighbor relationships. 156 */ 157 if ((nbr_find_ip(iface, ip_hdr.ip_src.s_addr) == NULL) && 158 (dvmrp_hdr->code == DVMRP_CODE_REPORT)) { 159 log_debug("recv_packet: route report from neighbor" 160 " ID %s, compat", inet_ntoa(ip_hdr.ip_src)); 161 nbr = nbr_new(ip_hdr.ip_src.s_addr, iface, 0); 162 nbr_fsm(nbr, NBR_EVT_PROBE_RCVD); 163 nbr->compat = 1; 164 nbr->addr = ip_hdr.ip_src; 165 } 166 167 if ((dvmrp_hdr->type == PKT_TYPE_DVMRP) && 168 (dvmrp_hdr->code != DVMRP_CODE_PROBE)) 169 /* find neighbor */ 170 if ((nbr = nbr_find_ip(iface, ip_hdr.ip_src.s_addr)) 171 == NULL) { 172 log_debug("recv_packet: unknown neighbor ID"); 173 return; 174 } 175 176 buf += sizeof(*dvmrp_hdr); 177 len = l - sizeof(*dvmrp_hdr); 178 179 inet_aton(AllDVMRPRouters, &addr); 180 if ((ip_hdr.ip_dst.s_addr != addr.s_addr) && 181 (ip_hdr.ip_dst.s_addr != iface->addr.s_addr)) { 182 log_debug("recv_packet: interface %s, invalid" 183 " destination IP address %s", iface->name, 184 inet_ntoa(ip_hdr.ip_dst)); 185 break; 186 } 187 188 switch (dvmrp_hdr->code) { 189 case DVMRP_CODE_PROBE: 190 recv_probe(iface, ip_hdr.ip_src, ip_hdr.ip_src.s_addr, 191 dvmrp_hdr->capabilities, buf, len); 192 break; 193 case DVMRP_CODE_REPORT: 194 recv_report(nbr, buf, len); 195 break; 196 case DVMRP_CODE_ASK_NBRS2: 197 recv_ask_nbrs2(nbr, buf,len); 198 break; 199 case DVMRP_CODE_NBRS2: 200 recv_nbrs2(nbr, buf,len); 201 break; 202 case DVMRP_CODE_PRUNE: 203 recv_prune(nbr, buf, len); 204 break; 205 case DVMRP_CODE_GRAFT: 206 recv_graft(nbr, buf,len); 207 break; 208 case DVMRP_CODE_GRAFT_ACK: 209 recv_graft_ack(nbr, buf,len); 210 break; 211 default: 212 log_debug("recv_packet: unknown DVMRP packet type, " 213 "interface %s", iface->name); 214 } 215 break; 216 /* IGMP */ 217 case PKT_TYPE_MEMBER_QUERY: 218 recv_igmp_query(iface, ip_hdr.ip_src, buf, len); 219 break; 220 case PKT_TYPE_MEMBER_REPORTv1: 221 case PKT_TYPE_MEMBER_REPORTv2: 222 recv_igmp_report(iface, ip_hdr.ip_src, buf, len, 223 dvmrp_hdr->type); 224 break; 225 case PKT_TYPE_LEAVE_GROUPv2: 226 recv_igmp_leave(iface, ip_hdr.ip_src, buf, len); 227 break; 228 default: 229 log_debug("recv_packet: unknown IGMP packet type, interface %s", 230 iface->name); 231 } 232 } 233 234 int 235 ip_hdr_sanity_check(const struct ip *ip_hdr, u_int16_t len) 236 { 237 if (ntohs(ip_hdr->ip_len) != len) { 238 log_debug("recv_packet: invalid IP packet length %u", 239 ntohs(ip_hdr->ip_len)); 240 return (-1); 241 } 242 243 if (ip_hdr->ip_p != IPPROTO_IGMP) 244 /* this is enforced by the socket itself */ 245 fatalx("recv_packet: invalid IP proto"); 246 247 return (ip_hdr->ip_hl << 2); 248 } 249 250 int 251 dvmrp_hdr_sanity_check(const struct ip *ip_hdr, struct dvmrp_hdr *dvmrp_hdr, 252 u_int16_t len, const struct iface *iface) 253 { 254 /* we only support DVMRPv3 */ 255 if (dvmrp_hdr->major_version != DVMRP_MAJOR_VERSION) { 256 log_debug("recv_packet: invalid DVMRP version"); 257 return (-1); 258 } 259 260 /* XXX enforce minor version as well, but not yet */ 261 262 /* XXX chksum */ 263 264 return (len); 265 } 266 267 struct iface * 268 find_iface(struct dvmrpd_conf *xconf, struct in_addr src) 269 { 270 struct iface *iface = NULL; 271 272 /* returned interface needs to be active */ 273 LIST_FOREACH(iface, &xconf->iface_list, entry) { 274 if (iface->fd > 0 && 275 (iface->type == IF_TYPE_POINTOPOINT) && 276 (iface->dst.s_addr == src.s_addr) && 277 !iface->passive) 278 return (iface); 279 280 if (iface->fd > 0 && (iface->addr.s_addr & 281 iface->mask.s_addr) == (src.s_addr & 282 iface->mask.s_addr) && !iface->passive) 283 return (iface); 284 } 285 286 return (NULL); 287 } 288