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/* $OpenBSD: packet.c,v 1.31 2014/10/25 03:23:49 lteo Exp $ */ |
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/* |
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* Copyright (c) 2004, 2005 Esben Norby <norby@openbsd.org> |
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* |
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* Permission to use, copy, modify, and distribute this software for any |
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* purpose with or without fee is hereby granted, provided that the above |
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* copyright notice and this permission notice appear in all copies. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
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*/ |
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#include <sys/types.h> |
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#include <sys/socket.h> |
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#include <sys/uio.h> |
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#include <netinet/in.h> |
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#include <netinet/ip.h> |
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#include <arpa/inet.h> |
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#include <net/if_dl.h> |
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#include <errno.h> |
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#include <event.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#include "ospfd.h" |
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#include "ospf.h" |
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#include "log.h" |
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#include "ospfe.h" |
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int ip_hdr_sanity_check(const struct ip *, u_int16_t); |
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int ospf_hdr_sanity_check(const struct ip *, |
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struct ospf_hdr *, u_int16_t, const struct iface *); |
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struct iface *find_iface(struct ospfd_conf *, unsigned int, struct in_addr); |
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int |
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gen_ospf_hdr(struct ibuf *buf, struct iface *iface, u_int8_t type) |
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{ |
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struct ospf_hdr ospf_hdr; |
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bzero(&ospf_hdr, sizeof(ospf_hdr)); |
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ospf_hdr.version = OSPF_VERSION; |
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ospf_hdr.type = type; |
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ospf_hdr.rtr_id = ospfe_router_id(); |
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if (iface->type != IF_TYPE_VIRTUALLINK) |
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ospf_hdr.area_id = iface->area->id.s_addr; |
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ospf_hdr.auth_type = htons(iface->auth_type); |
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return (ibuf_add(buf, &ospf_hdr, sizeof(ospf_hdr))); |
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} |
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/* send and receive packets */ |
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int |
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send_packet(struct iface *iface, struct ibuf *buf, struct sockaddr_in *dst) |
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{ |
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struct msghdr msg; |
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struct iovec iov[2]; |
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struct ip ip_hdr; |
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/* setup IP hdr */ |
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bzero(&ip_hdr, sizeof(ip_hdr)); |
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ip_hdr.ip_v = IPVERSION; |
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ip_hdr.ip_hl = sizeof(ip_hdr) >> 2; |
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ip_hdr.ip_tos = IPTOS_PREC_INTERNETCONTROL; |
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ip_hdr.ip_len = htons(ibuf_size(buf) + sizeof(ip_hdr)); |
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ip_hdr.ip_id = 0; /* 0 means kernel set appropriate value */ |
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ip_hdr.ip_off = 0; |
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ip_hdr.ip_ttl = iface->type != IF_TYPE_VIRTUALLINK ? |
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IP_DEFAULT_MULTICAST_TTL : MAXTTL; |
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ip_hdr.ip_p = IPPROTO_OSPF; |
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ip_hdr.ip_sum = 0; |
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ip_hdr.ip_src = iface->addr; |
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ip_hdr.ip_dst = dst->sin_addr; |
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/* setup buffer */ |
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bzero(&msg, sizeof(msg)); |
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iov[0].iov_base = &ip_hdr; |
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iov[0].iov_len = sizeof(ip_hdr); |
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iov[1].iov_base = buf->buf; |
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iov[1].iov_len = ibuf_size(buf); |
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msg.msg_name = dst; |
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msg.msg_namelen = sizeof(*dst); |
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msg.msg_iov = iov; |
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msg.msg_iovlen = 2; |
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/* set outgoing interface for multicast traffic */ |
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if (IN_MULTICAST(ntohl(dst->sin_addr.s_addr))) |
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if (if_set_mcast(iface) == -1) |
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return (-1); |
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if (sendmsg(iface->fd, &msg, 0) == -1) { |
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log_warn("send_packet: error sending packet on interface %s", |
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iface->name); |
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return (-1); |
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} |
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return (0); |
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} |
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void |
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recv_packet(int fd, short event, void *bula) |
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{ |
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union { |
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struct cmsghdr hdr; |
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char buf[CMSG_SPACE(sizeof(struct sockaddr_dl))]; |
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} cmsgbuf; |
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struct msghdr msg; |
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struct iovec iov; |
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struct ip ip_hdr; |
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struct in_addr addr; |
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struct ospfd_conf *xconf = bula; |
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struct ospf_hdr *ospf_hdr; |
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struct iface *iface; |
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struct nbr *nbr = NULL; |
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char *buf; |
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struct cmsghdr *cmsg; |
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ssize_t r; |
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u_int16_t len; |
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int l; |
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unsigned int ifindex = 0; |
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if (event != EV_READ) |
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return; |
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/* setup buffer */ |
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bzero(&msg, sizeof(msg)); |
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iov.iov_base = buf = pkt_ptr; |
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iov.iov_len = READ_BUF_SIZE; |
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msg.msg_iov = &iov; |
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msg.msg_iovlen = 1; |
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msg.msg_control = &cmsgbuf.buf; |
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msg.msg_controllen = sizeof(cmsgbuf.buf); |
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if ((r = recvmsg(fd, &msg, 0)) == -1) { |
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if (errno != EAGAIN && errno != EINTR) |
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log_debug("recv_packet: read error: %s", |
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strerror(errno)); |
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return; |
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} |
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for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; |
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cmsg = CMSG_NXTHDR(&msg, cmsg)) { |
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if (cmsg->cmsg_level == IPPROTO_IP && |
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cmsg->cmsg_type == IP_RECVIF) { |
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ifindex = ((struct sockaddr_dl *) |
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CMSG_DATA(cmsg))->sdl_index; |
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break; |
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} |
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} |
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len = (u_int16_t)r; |
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/* IP header sanity checks */ |
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if (len < sizeof(ip_hdr)) { |
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log_warnx("recv_packet: bad packet size"); |
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return; |
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} |
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memcpy(&ip_hdr, buf, sizeof(ip_hdr)); |
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if ((l = ip_hdr_sanity_check(&ip_hdr, len)) == -1) |
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return; |
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buf += l; |
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len -= l; |
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/* find a matching interface */ |
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if ((iface = find_iface(xconf, ifindex, ip_hdr.ip_src)) == NULL) { |
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/* XXX add a counter here */ |
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return; |
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} |
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/* |
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* Packet needs to be sent to AllSPFRouters or AllDRouters |
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* or to the address of the interface itself. |
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* AllDRouters is only valid for DR and BDR but this is checked later. |
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*/ |
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inet_aton(AllSPFRouters, &addr); |
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if (ip_hdr.ip_dst.s_addr != addr.s_addr) { |
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inet_aton(AllDRouters, &addr); |
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if (ip_hdr.ip_dst.s_addr != addr.s_addr) { |
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if (ip_hdr.ip_dst.s_addr != iface->addr.s_addr) { |
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log_debug("recv_packet: packet sent to wrong " |
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"address %s, interface %s", |
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inet_ntoa(ip_hdr.ip_dst), iface->name); |
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return; |
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} |
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} |
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} |
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/* OSPF header sanity checks */ |
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if (len < sizeof(*ospf_hdr)) { |
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log_debug("recv_packet: bad packet size"); |
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return; |
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} |
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ospf_hdr = (struct ospf_hdr *)buf; |
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if ((l = ospf_hdr_sanity_check(&ip_hdr, ospf_hdr, len, iface)) == -1) |
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return; |
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nbr = nbr_find_id(iface, ospf_hdr->rtr_id); |
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if (ospf_hdr->type != PACKET_TYPE_HELLO && nbr == NULL) { |
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log_debug("recv_packet: unknown neighbor ID"); |
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return; |
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} |
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if (auth_validate(buf, len, iface, nbr)) { |
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log_warnx("recv_packet: authentication error, " |
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"interface %s", iface->name); |
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return; |
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} |
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buf += sizeof(*ospf_hdr); |
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len = l - sizeof(*ospf_hdr); |
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/* switch OSPF packet type */ |
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switch (ospf_hdr->type) { |
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case PACKET_TYPE_HELLO: |
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inet_aton(AllDRouters, &addr); |
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if (ip_hdr.ip_dst.s_addr == addr.s_addr) { |
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log_debug("recv_packet: invalid destination IP " |
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"address"); |
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break; |
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} |
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recv_hello(iface, ip_hdr.ip_src, ospf_hdr->rtr_id, buf, len); |
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break; |
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case PACKET_TYPE_DD: |
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recv_db_description(nbr, buf, len); |
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break; |
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case PACKET_TYPE_LS_REQUEST: |
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recv_ls_req(nbr, buf, len); |
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break; |
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case PACKET_TYPE_LS_UPDATE: |
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recv_ls_update(nbr, buf, len); |
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break; |
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case PACKET_TYPE_LS_ACK: |
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recv_ls_ack(nbr, buf, len); |
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break; |
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default: |
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log_debug("recv_packet: unknown OSPF packet type, interface %s", |
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iface->name); |
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} |
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} |
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int |
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ip_hdr_sanity_check(const struct ip *ip_hdr, u_int16_t len) |
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{ |
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if (ntohs(ip_hdr->ip_len) != len) { |
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log_debug("recv_packet: invalid IP packet length %u", |
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ntohs(ip_hdr->ip_len)); |
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return (-1); |
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} |
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if (ip_hdr->ip_p != IPPROTO_OSPF) |
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/* this is enforced by the socket itself */ |
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fatalx("recv_packet: invalid IP proto"); |
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return (ip_hdr->ip_hl << 2); |
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} |
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int |
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ospf_hdr_sanity_check(const struct ip *ip_hdr, struct ospf_hdr *ospf_hdr, |
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u_int16_t len, const struct iface *iface) |
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{ |
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struct in_addr addr; |
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if (ospf_hdr->version != OSPF_VERSION) { |
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log_debug("recv_packet: invalid OSPF version %d", |
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ospf_hdr->version); |
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return (-1); |
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} |
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if (ntohs(ospf_hdr->len) > len || |
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len <= sizeof(struct ospf_hdr)) { |
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log_debug("recv_packet: invalid OSPF packet length %d", |
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ntohs(ospf_hdr->len)); |
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return (-1); |
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} |
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if (iface->type != IF_TYPE_VIRTUALLINK) { |
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if (ospf_hdr->area_id != iface->area->id.s_addr) { |
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addr.s_addr = ospf_hdr->area_id; |
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log_debug("recv_packet: invalid area ID %s, " |
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"interface %s", inet_ntoa(addr), iface->name); |
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return (-1); |
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} |
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} else { |
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if (ospf_hdr->area_id != 0) { |
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addr.s_addr = ospf_hdr->area_id; |
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log_debug("recv_packet: invalid area ID %s, " |
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"interface %s", inet_ntoa(addr), iface->name); |
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return (-1); |
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} |
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} |
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if (iface->type == IF_TYPE_BROADCAST || iface->type == IF_TYPE_NBMA) { |
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if (inet_aton(AllDRouters, &addr) == 0) |
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fatalx("recv_packet: inet_aton"); |
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if (ip_hdr->ip_dst.s_addr == addr.s_addr && |
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(iface->state & IF_STA_DRORBDR) == 0) { |
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log_debug("recv_packet: invalid destination IP in " |
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"state %s, interface %s", |
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if_state_name(iface->state), iface->name); |
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return (-1); |
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} |
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} |
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return (ntohs(ospf_hdr->len)); |
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} |
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struct iface * |
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find_iface(struct ospfd_conf *xconf, unsigned int ifindex, struct in_addr src) |
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{ |
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struct area *area = NULL; |
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struct iface *iface = NULL; |
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/* returned interface needs to be active */ |
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LIST_FOREACH(area, &xconf->area_list, entry) { |
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LIST_FOREACH(iface, &area->iface_list, entry) { |
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switch (iface->type) { |
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case IF_TYPE_VIRTUALLINK: |
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if ((src.s_addr == iface->dst.s_addr) && |
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!iface->passive) |
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return (iface); |
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break; |
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case IF_TYPE_POINTOPOINT: |
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if (ifindex == iface->ifindex && |
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!iface->passive) |
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return (iface); |
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break; |
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default: |
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if (ifindex == iface->ifindex && |
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(iface->addr.s_addr & iface->mask.s_addr) == |
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(src.s_addr & iface->mask.s_addr) && |
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!iface->passive) |
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return (iface); |
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break; |
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} |
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} |
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} |
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return (NULL); |
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} |