1 /* $OpenBSD: packet.c,v 1.6 2021/01/19 11:46:10 claudio 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 char pkt[READ_BUF_SIZE]; 101 ssize_t r; 102 u_int16_t len; 103 int l; 104 105 if (event != EV_READ) 106 return; 107 108 if ((r = recvfrom(fd, pkt, sizeof(pkt), 0, NULL, NULL)) == -1) { 109 if (errno != EAGAIN && errno != EINTR) 110 log_debug("recv_packet: error receiving packet"); 111 return; 112 } 113 114 len = (u_int16_t)r; 115 buf = pkt; 116 117 /* IP header sanity checks */ 118 if (len < sizeof(ip_hdr)) { 119 log_warnx("recv_packet: bad packet size"); 120 return; 121 } 122 123 memcpy(&ip_hdr, buf, sizeof(ip_hdr)); 124 if ((l = ip_hdr_sanity_check(&ip_hdr, len)) == -1) 125 return; 126 buf += l; 127 len -= l; 128 129 /* find a matching interface */ 130 if ((iface = find_iface(xconf, ip_hdr.ip_src)) == NULL) { 131 log_debug("recv_packet: cannot find valid interface, ip src %s", 132 inet_ntoa(ip_hdr.ip_src)); 133 return; 134 } 135 136 /* header sanity checks */ 137 if (len < sizeof(*dvmrp_hdr)) { 138 log_warnx("recv_packet: bad packet size"); 139 return; 140 } 141 dvmrp_hdr = (struct dvmrp_hdr *)buf; 142 143 switch (dvmrp_hdr->type) { 144 /* DVMRP */ 145 case PKT_TYPE_DVMRP: 146 if ((l = dvmrp_hdr_sanity_check(&ip_hdr, dvmrp_hdr, len, 147 iface)) == -1) 148 return; 149 150 /* 151 * mrouted compat 152 * 153 * Old mrouted versions, send route reports before establishing 154 * 2-WAY neighbor relationships. 155 */ 156 if ((nbr_find_ip(iface, ip_hdr.ip_src.s_addr) == NULL) && 157 (dvmrp_hdr->code == DVMRP_CODE_REPORT)) { 158 log_debug("recv_packet: route report from neighbor" 159 " ID %s, compat", inet_ntoa(ip_hdr.ip_src)); 160 nbr = nbr_new(ip_hdr.ip_src.s_addr, iface, 0); 161 nbr_fsm(nbr, NBR_EVT_PROBE_RCVD); 162 nbr->compat = 1; 163 nbr->addr = ip_hdr.ip_src; 164 } 165 166 if ((dvmrp_hdr->type == PKT_TYPE_DVMRP) && 167 (dvmrp_hdr->code != DVMRP_CODE_PROBE)) 168 /* find neighbor */ 169 if ((nbr = nbr_find_ip(iface, ip_hdr.ip_src.s_addr)) 170 == NULL) { 171 log_debug("recv_packet: unknown neighbor ID"); 172 return; 173 } 174 175 buf += sizeof(*dvmrp_hdr); 176 len = l - sizeof(*dvmrp_hdr); 177 178 inet_aton(AllDVMRPRouters, &addr); 179 if ((ip_hdr.ip_dst.s_addr != addr.s_addr) && 180 (ip_hdr.ip_dst.s_addr != iface->addr.s_addr)) { 181 log_debug("recv_packet: interface %s, invalid" 182 " destination IP address %s", iface->name, 183 inet_ntoa(ip_hdr.ip_dst)); 184 break; 185 } 186 187 switch (dvmrp_hdr->code) { 188 case DVMRP_CODE_PROBE: 189 recv_probe(iface, ip_hdr.ip_src, ip_hdr.ip_src.s_addr, 190 dvmrp_hdr->capabilities, buf, len); 191 break; 192 case DVMRP_CODE_REPORT: 193 recv_report(nbr, buf, len); 194 break; 195 case DVMRP_CODE_ASK_NBRS2: 196 recv_ask_nbrs2(nbr, buf,len); 197 break; 198 case DVMRP_CODE_NBRS2: 199 recv_nbrs2(nbr, buf,len); 200 break; 201 case DVMRP_CODE_PRUNE: 202 recv_prune(nbr, buf, len); 203 break; 204 case DVMRP_CODE_GRAFT: 205 recv_graft(nbr, buf,len); 206 break; 207 case DVMRP_CODE_GRAFT_ACK: 208 recv_graft_ack(nbr, buf,len); 209 break; 210 default: 211 log_debug("recv_packet: unknown DVMRP packet type, " 212 "interface %s", iface->name); 213 } 214 break; 215 /* IGMP */ 216 case PKT_TYPE_MEMBER_QUERY: 217 recv_igmp_query(iface, ip_hdr.ip_src, buf, len); 218 break; 219 case PKT_TYPE_MEMBER_REPORTv1: 220 case PKT_TYPE_MEMBER_REPORTv2: 221 recv_igmp_report(iface, ip_hdr.ip_src, buf, len, 222 dvmrp_hdr->type); 223 break; 224 case PKT_TYPE_LEAVE_GROUPv2: 225 recv_igmp_leave(iface, ip_hdr.ip_src, buf, len); 226 break; 227 default: 228 log_debug("recv_packet: unknown IGMP packet type, interface %s", 229 iface->name); 230 } 231 } 232 233 int 234 ip_hdr_sanity_check(const struct ip *ip_hdr, u_int16_t len) 235 { 236 if (ntohs(ip_hdr->ip_len) != len) { 237 log_debug("recv_packet: invalid IP packet length %u", 238 ntohs(ip_hdr->ip_len)); 239 return (-1); 240 } 241 242 if (ip_hdr->ip_p != IPPROTO_IGMP) 243 /* this is enforced by the socket itself */ 244 fatalx("recv_packet: invalid IP proto"); 245 246 return (ip_hdr->ip_hl << 2); 247 } 248 249 int 250 dvmrp_hdr_sanity_check(const struct ip *ip_hdr, struct dvmrp_hdr *dvmrp_hdr, 251 u_int16_t len, const struct iface *iface) 252 { 253 /* we only support DVMRPv3 */ 254 if (dvmrp_hdr->major_version != DVMRP_MAJOR_VERSION) { 255 log_debug("recv_packet: invalid DVMRP version"); 256 return (-1); 257 } 258 259 /* XXX enforce minor version as well, but not yet */ 260 261 /* XXX chksum */ 262 263 return (len); 264 } 265 266 struct iface * 267 find_iface(struct dvmrpd_conf *xconf, struct in_addr src) 268 { 269 struct iface *iface = NULL; 270 271 /* returned interface needs to be active */ 272 LIST_FOREACH(iface, &xconf->iface_list, entry) { 273 if (iface->fd > 0 && 274 (iface->type == IF_TYPE_POINTOPOINT) && 275 (iface->dst.s_addr == src.s_addr) && 276 !iface->passive) 277 return (iface); 278 279 if (iface->fd > 0 && (iface->addr.s_addr & 280 iface->mask.s_addr) == (src.s_addr & 281 iface->mask.s_addr) && !iface->passive) 282 return (iface); 283 } 284 285 return (NULL); 286 } 287