/* * Copyright 2004 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. * * Copyright (c) 1983, 1988, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgment: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * $FreeBSD: src/sbin/routed/input.c,v 1.9 2001/06/06 20:52:30 phk Exp $ */ #pragma ident "%Z%%M% %I% %E% SMI" #include "defs.h" #include /* * The size of the control buffer passed to recvmsg() used to receive * ancillary data. */ #define CONTROL_BUFSIZE 1024 static void input(struct sockaddr_in *, struct interface *, struct rip *, int); static boolean_t ck_passwd(struct interface *, struct rip *, uint8_t *, in_addr_t, struct msg_limit *); /* * Find the interface which received the given message. */ struct interface * receiving_interface(struct msghdr *msg, boolean_t findremote) { struct interface *ifp, *ifp1, *ifp2; struct sockaddr_in *from; void *opt; uint_t ifindex; from = (struct sockaddr_in *)msg->msg_name; /* First see if this packet came from a remote gateway. */ if (findremote && ((ifp = findremoteif(from->sin_addr.s_addr)) != NULL)) return (ifp); /* * It did not come from a remote gateway. Determine which * physical interface this packet was received on by * processing the message's ancillary data to find the * IP_RECVIF option we requested. */ if ((opt = find_ancillary(msg, IP_RECVIF)) == NULL) { msglog("unable to retrieve IP_RECVIF"); } else { ifindex = *(uint_t *)opt; if ((ifp = ifwithindex(ifindex, _B_TRUE)) != NULL) { /* Find the best match of the aliases */ ifp2 = NULL; for (ifp1 = ifp; ifp1 != NULL; ifp1 = ifp1->int_ilist.hl_next) { if (ifp1->int_addr == from->sin_addr.s_addr) return (ifp1); if ((ifp2 == NULL || (ifp2->int_state & IS_ALIAS)) && on_net(from->sin_addr.s_addr, ifp1->int_net, ifp1->int_mask)) ifp2 = ifp1; } if (ifp2 != NULL) ifp = ifp2; return (ifp); } } /* * As a last resort (for some reason, ip didn't give us the * IP_RECVIF index we requested), try to deduce the receiving * interface based on the source address of the packet. */ return (iflookup(from->sin_addr.s_addr)); } /* * Process RIP input on rip_sock. Returns 0 for success, -1 for failure. */ int read_rip() { struct sockaddr_in from; struct interface *ifp; int cc; union pkt_buf inbuf; struct msghdr msg; struct iovec iov; uint8_t ancillary_data[CONTROL_BUFSIZE]; iov.iov_base = &inbuf; iov.iov_len = sizeof (inbuf); msg.msg_iov = &iov; msg.msg_iovlen = 1; msg.msg_name = &from; msg.msg_control = &ancillary_data; for (;;) { msg.msg_namelen = sizeof (from); msg.msg_controllen = sizeof (ancillary_data); cc = recvmsg(rip_sock, &msg, 0); if (cc == 0) return (-1); if (cc < 0) { if (errno == EWOULDBLOCK || errno == EINTR) return (0); LOGERR("recvmsg(rip_sock)"); return (-1); } /* * ifp is the interface via which the packet arrived. */ ifp = receiving_interface(&msg, _B_TRUE); input(&from, ifp, &inbuf.rip, cc); } } /* Process a RIP packet */ static void input(struct sockaddr_in *from, /* received from this IP address */ struct interface *ifp, /* interface of incoming socket */ struct rip *rip, int cc) { #define FROM_NADDR from->sin_addr.s_addr static struct msg_limit use_auth, bad_len, bad_mask; static struct msg_limit unk_router, bad_router, bad_nhop; struct rt_entry *rt; struct rt_spare new; struct netinfo *n, *lim; struct interface *ifp1; in_addr_t gate, mask, v1_mask, dst, ddst_h = 0; struct auth *ap; struct tgate *tg = NULL; struct tgate_net *tn; int i, j; boolean_t poll_answer = _B_FALSE; /* Set to _B_TRUE if RIPCMD_POLL */ uint16_t rt_state = 0; /* Extra route state to pass to input_route() */ uint8_t metric; (void) memset(&new, 0, sizeof (new)); /* Notice when we hear from a remote gateway */ if (ifp != NULL && (ifp->int_state & IS_REMOTE)) ifp->int_act_time = now.tv_sec; trace_rip("Recv", "from", from, ifp, rip, cc); if (ifp != NULL && (ifp->int_if_flags & IFF_NORTEXCH)) { trace_misc("discard RIP packet received over %s (IFF_NORTEXCH)", ifp->int_name); return; } gate = ntohl(FROM_NADDR); if (IN_EXPERIMENTAL(gate) || (gate >> IN_CLASSA_NSHIFT) == 0) { msglim(&bad_router, FROM_NADDR, "source address %s unusable", naddr_ntoa(FROM_NADDR)); return; } if (rip->rip_vers == 0) { msglim(&bad_router, FROM_NADDR, "RIP version 0, cmd %d, packet received from %s", rip->rip_cmd, naddr_ntoa(FROM_NADDR)); return; } if (rip->rip_vers > RIPv2) { msglim(&bad_router, FROM_NADDR, "Treating RIP version %d packet received from %s as " "version %d", rip->rip_vers, naddr_ntoa(FROM_NADDR), RIPv2); rip->rip_vers = RIPv2; } if (cc > (int)OVER_MAXPACKETSIZE) { msglim(&bad_router, FROM_NADDR, "packet at least %d bytes too long received from %s", cc-MAXPACKETSIZE, naddr_ntoa(FROM_NADDR)); } n = rip->rip_nets; lim = n + (cc - 4) / sizeof (struct netinfo); /* * Notice authentication. * As required by section 5.2 of RFC 2453, discard authenticated * RIPv2 messages, but only if configured for that silliness. * * RIPv2 authentication is lame. Why authenticate queries? * Why should a RIPv2 implementation with authentication disabled * not be able to listen to RIPv2 packets with authentication, while * RIPv1 systems will listen? Crazy! */ if (!auth_ok && rip->rip_vers == RIPv2 && n < lim && n->n_family == RIP_AF_AUTH) { msglim(&use_auth, FROM_NADDR, "RIPv2 message with authentication from %s discarded", naddr_ntoa(FROM_NADDR)); return; } switch (rip->rip_cmd) { case RIPCMD_POLL: /* * Similar to RIPCMD_REQUEST, this command is used to * request either a full-table or a set of entries. Both * silent processes and routers can respond to this * command. */ poll_answer = _B_TRUE; /* FALLTHRU */ case RIPCMD_REQUEST: /* Are we talking to ourself or a remote gateway? */ ifp1 = ifwithaddr(FROM_NADDR, _B_FALSE, _B_TRUE); if (ifp1 != NULL) { if (ifp1->int_state & IS_REMOTE) { /* remote gateway */ ifp = ifp1; if (check_remote(ifp)) { ifp->int_act_time = now.tv_sec; if_ok(ifp, "remote ", _B_FALSE); } } else if (from->sin_port == htons(RIP_PORT)) { trace_pkt(" discard our own RIP request"); return; } } /* did the request come from a router? */ if (!poll_answer && (from->sin_port == htons(RIP_PORT))) { /* * yes, ignore the request if RIP is off so that * the router does not depend on us. */ if (ripout_interfaces == 0 || (ifp != NULL && (IS_RIP_OUT_OFF(ifp->int_state) || !IS_IFF_ROUTING(ifp->int_if_flags)))) { trace_pkt(" discard request while RIP off"); return; } } /* * According to RFC 2453 section 5.2, we should ignore * unauthenticated queries when authentication is * configured. That is too silly to bother with. Sheesh! * Are forwarding tables supposed to be secret even though * a bad guy can infer them with test traffic? RIP is * still the most common router-discovery protocol, so * hosts need to send queries that will be answered. What * about `rtquery`? Maybe on firewalls you'd care, but not * enough to give up the diagnostic facilities of remote * probing. */ if (n >= lim) { msglim(&bad_len, FROM_NADDR, "empty request from %s", naddr_ntoa(FROM_NADDR)); return; } if (cc%sizeof (*n) != sizeof (struct rip)%sizeof (*n)) { msglim(&bad_len, FROM_NADDR, "request of bad length (%d) from %s", cc, naddr_ntoa(FROM_NADDR)); } if (rip->rip_vers == RIPv2 && (ifp == NULL || (ifp->int_state & IS_NO_RIPV1_OUT))) { v12buf.buf->rip_vers = RIPv2; /* * If we have a secret but it is a cleartext secret, * do not disclose our secret unless the other guy * already knows it. */ ap = find_auth(ifp); if (ap != NULL && (ulong_t)ap->end < (ulong_t)clk.tv_sec) { /* * Don't authenticate incoming packets * using an expired key. */ msglim(&use_auth, FROM_NADDR, "%s attempting to authenticate using " "an expired password.", naddr_ntoa(FROM_NADDR)); ap = NULL; } if (ap != NULL && ap->type == RIP_AUTH_PW && (n->n_family != RIP_AF_AUTH || !ck_passwd(ifp, rip, (uint8_t *)lim, FROM_NADDR, &use_auth))) ap = NULL; } else { v12buf.buf->rip_vers = RIPv1; ap = NULL; } clr_ws_buf(&v12buf, ap); do { n->n_metric = ntohl(n->n_metric); /* * A single entry with family RIP_AF_UNSPEC and * metric HOPCNT_INFINITY means "all routes". * We respond to routers only if we are acting * as a supplier, or to anyone other than a router * (i.e. a query). */ if (n->n_family == RIP_AF_UNSPEC && n->n_metric == HOPCNT_INFINITY) { /* * Answer a full-table query from a utility * program with all we know. */ if (poll_answer || (from->sin_port != htons(RIP_PORT))) { supply(from, ifp, OUT_QUERY, 0, rip->rip_vers, ap != NULL); return; } /* * A router is trying to prime its tables. * Filter the answer in the same way * broadcasts are filtered. * * Only answer a router if we are a supplier * to keep an unwary host that is just starting * from picking us as a router. */ if (ifp == NULL) { trace_pkt("ignore distant router"); return; } if (IS_RIP_OFF(ifp->int_state) || !should_supply(ifp)) { trace_pkt("ignore; not supplying"); return; } /* * Do not answer a RIPv1 router if * we are sending RIPv2. But do offer * poor man's router discovery. */ if ((ifp->int_state & IS_NO_RIPV1_OUT) && rip->rip_vers == RIPv1) { if (!(ifp->int_state & IS_PM_RDISC)) { trace_pkt("ignore; sending RIPv2"); return; } v12buf.n->n_family = RIP_AF_INET; v12buf.n->n_dst = RIP_DEFAULT; metric = ifp->int_d_metric; if (NULL != (rt = rtget(RIP_DEFAULT, 0))) metric = MIN(metric, (rt->rt_metric + 1)); v12buf.n->n_metric = htonl(metric); v12buf.n++; break; } /* * Respond with RIPv1 instead of RIPv2 if * that is what we are broadcasting on the * interface to keep the remote router from * getting the wrong initial idea of the * routes we send. */ supply(from, ifp, OUT_UNICAST, 0, (ifp->int_state & IS_NO_RIPV1_OUT) ? RIPv2 : RIPv1, ap != NULL); return; } /* Ignore authentication */ if (n->n_family == RIP_AF_AUTH) continue; if (n->n_family != RIP_AF_INET) { msglim(&bad_router, FROM_NADDR, "request from %s for unsupported" " (af %d) %s", naddr_ntoa(FROM_NADDR), ntohs(n->n_family), naddr_ntoa(n->n_dst)); return; } /* We are being asked about a specific destination. */ v12buf.n->n_dst = dst = n->n_dst; v12buf.n->n_family = RIP_AF_INET; if (!check_dst(dst)) { msglim(&bad_router, FROM_NADDR, "bad queried destination %s from %s", naddr_ntoa(dst), naddr_ntoa(FROM_NADDR)); v12buf.n->n_metric = HOPCNT_INFINITY; goto rte_done; } /* decide what mask was intended */ if (rip->rip_vers == RIPv1 || 0 == (mask = ntohl(n->n_mask)) || 0 != (ntohl(dst) & ~mask)) mask = ripv1_mask_host(dst, ifp); /* * Try to find the answer. If we don't have an * explicit route for the destination, use the best * route to the destination. */ rt = rtget(dst, mask); if (rt == NULL && dst != RIP_DEFAULT) rt = rtfind(n->n_dst); if (v12buf.buf->rip_vers != RIPv1) v12buf.n->n_mask = htonl(mask); if (rt == NULL) { /* we do not have the answer */ v12buf.n->n_metric = HOPCNT_INFINITY; goto rte_done; } /* * we have the answer, so compute the right metric * and next hop. */ v12buf.n->n_metric = rt->rt_metric + 1; if (v12buf.n->n_metric > HOPCNT_INFINITY) v12buf.n->n_metric = HOPCNT_INFINITY; if (v12buf.buf->rip_vers != RIPv1) { v12buf.n->n_tag = rt->rt_tag; if (ifp != NULL && on_net(rt->rt_gate, ifp->int_net, ifp->int_mask) && rt->rt_gate != ifp->int_addr) v12buf.n->n_nhop = rt->rt_gate; } rte_done: v12buf.n->n_metric = htonl(v12buf.n->n_metric); /* * Stop paying attention if we fill the output buffer. */ if (++v12buf.n >= v12buf.lim) break; } while (++n < lim); /* * If our response is authenticated with md5, complete the * md5 computation. */ if (ap != NULL && ap->type == RIP_AUTH_MD5) end_md5_auth(&v12buf, ap); /* * Diagnostic programs make specific requests * from ports other than 520. Log other types * of specific requests as suspicious. */ if (!poll_answer && (from->sin_port == htons(RIP_PORT))) { writelog(LOG_WARNING, "Received suspicious request from %s port %d", naddr_ntoa(FROM_NADDR), RIP_PORT); } if (poll_answer || (from->sin_port != htons(RIP_PORT))) { /* query */ (void) output(OUT_QUERY, from, ifp, v12buf.buf, ((char *)v12buf.n - (char *)v12buf.buf)); } else { (void) output(OUT_UNICAST, from, ifp, v12buf.buf, ((char *)v12buf.n - (char *)v12buf.buf)); } return; case RIPCMD_TRACEON: case RIPCMD_TRACEOFF: /* * Notice that trace messages are turned off for all possible * abuse if PATH_TRACE is undefined in pathnames.h. * Notice also that because of the way the trace file is * handled in trace.c, no abuse is plausible even if * PATH_TRACE is defined. * * First verify message came from a privileged port. */ if (ntohs(from->sin_port) > IPPORT_RESERVED) { trace_pkt("trace command from untrusted port %d on %s", ntohs(from->sin_port), naddr_ntoa(FROM_NADDR)); return; } if (ifp == NULL || !remote_address_ok(ifp, FROM_NADDR)) { /* * Use a message here to warn about strange * messages from remote systems. */ msglim(&bad_router, FROM_NADDR, "trace command from non-local host %s", naddr_ntoa(FROM_NADDR)); return; } if (ifp->int_state & IS_DISTRUST) { tg = tgates; while (tg->tgate_addr != FROM_NADDR) { tg = tg->tgate_next; if (tg == NULL) { trace_pkt("trace command from " "untrusted host %s", naddr_ntoa(FROM_NADDR)); return; } } } if (ifp->int_auth[0].type != RIP_AUTH_NONE) { /* * Technically, it would be fairly easy to add * standard authentication to the existing * trace commands -- just bracket the payload * with the authentication information. * However, the tracing message behavior * itself is marginal enough that we don't * actually care. Just discard if * authentication is needed. */ trace_pkt("trace command unauthenticated from %s", naddr_ntoa(FROM_NADDR)); return; } if (rip->rip_cmd == RIPCMD_TRACEON) { rip->rip_tracefile[cc-4] = '\0'; set_tracefile(rip->rip_tracefile, "trace command: %s\n", 0); } else { trace_off("tracing turned off by %s", naddr_ntoa(FROM_NADDR)); } return; case RIPCMD_RESPONSE: if (ifp != NULL && (ifp->int_if_flags & IFF_NOXMIT)) { trace_misc("discard RIP response received over %s " "(IFF_NOXMIT)", ifp->int_name); return; } if (cc%sizeof (*n) != sizeof (struct rip)%sizeof (*n)) { msglim(&bad_len, FROM_NADDR, "response of bad length (%d) from %s", cc, naddr_ntoa(FROM_NADDR)); } if ((ntohl(FROM_NADDR) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { msglim(&bad_router, FROM_NADDR, "discard RIP response from bad source address %s", naddr_ntoa(FROM_NADDR)); return; } /* verify message came from a router */ if (from->sin_port != htons(RIP_PORT)) { msglim(&bad_router, FROM_NADDR, " discard RIP response from unknown port" " %d on host %s", ntohs(from->sin_port), naddr_ntoa(FROM_NADDR)); return; } if (!rip_enabled) { trace_pkt(" discard response while RIP off"); return; } /* Are we talking to ourself or a remote gateway? */ ifp1 = ifwithaddr(FROM_NADDR, _B_FALSE, _B_TRUE); if (ifp1 != NULL) { if (ifp1->int_state & IS_REMOTE) { /* remote gateway */ ifp = ifp1; if (check_remote(ifp)) { ifp->int_act_time = now.tv_sec; if_ok(ifp, "remote ", _B_FALSE); } } else { trace_pkt(" discard our own RIP response"); return; } } else { /* * If it's not a remote gateway, then the * remote address *must* be directly * connected. Make sure that it is. */ if (ifp != NULL && !remote_address_ok(ifp, FROM_NADDR)) { msglim(&bad_router, FROM_NADDR, "discard RIP response; source %s not on " "interface %s", naddr_ntoa(FROM_NADDR), ifp->int_name); return; } } /* * Accept routing packets from routers directly connected * via broadcast or point-to-point networks, and from * those listed in /etc/gateways. */ if (ifp == NULL) { msglim(&unk_router, FROM_NADDR, " discard response from %s" " via unexpected interface", naddr_ntoa(FROM_NADDR)); return; } if (IS_RIP_IN_OFF(ifp->int_state)) { trace_pkt(" discard RIPv%d response" " via disabled interface %s", rip->rip_vers, ifp->int_name); return; } if (n >= lim) { msglim(&bad_len, FROM_NADDR, "empty response from %s", naddr_ntoa(FROM_NADDR)); return; } if (((ifp->int_state & IS_NO_RIPV1_IN) && rip->rip_vers == RIPv1) || ((ifp->int_state & IS_NO_RIPV2_IN) && rip->rip_vers != RIPv1)) { trace_pkt(" discard RIPv%d response", rip->rip_vers); return; } /* * Continue to listen to routes via broken interfaces * which might be declared IS_BROKE because of * device-driver idiosyncracies, but might otherwise * be perfectly healthy. */ if (ifp->int_state & IS_BROKE) { trace_pkt("response via broken interface %s", ifp->int_name); } /* * If the interface cares, ignore bad routers. * Trace but do not log this problem, because where it * happens, it happens frequently. */ if (ifp->int_state & IS_DISTRUST) { tg = tgates; while (tg->tgate_addr != FROM_NADDR) { tg = tg->tgate_next; if (tg == NULL) { trace_pkt(" discard RIP response" " from untrusted router %s", naddr_ntoa(FROM_NADDR)); return; } } } /* * Authenticate the packet if we have a secret. * If we do not have any secrets, ignore the error in * RFC 1723 and accept it regardless. */ if (ifp->int_auth[0].type != RIP_AUTH_NONE && rip->rip_vers != RIPv1 && !ck_passwd(ifp, rip, (uint8_t *)lim, FROM_NADDR, &use_auth)) return; /* * Do this only if we're supplying routes to *nobody*. */ if (!should_supply(NULL) && save_space) { /* * "-S" option. Instead of entering all routes, * only enter a default route for the sender of * this RESPONSE message */ /* Should we trust this route from this router? */ if (tg != NULL && tg->tgate_nets->mask != 0) { trace_pkt(" ignored unauthorized %s", addrname(RIP_DEFAULT, 0, 0)); break; } new.rts_gate = FROM_NADDR; new.rts_router = FROM_NADDR; new.rts_metric = HOPCNT_INFINITY-1; new.rts_tag = n->n_tag; new.rts_time = now.tv_sec; new.rts_ifp = ifp; new.rts_de_ag = 0; new.rts_origin = RO_RIP; /* * Add the newly generated default route, but don't * propagate the madness. Treat it the same way as * default routes learned from Router Discovery. */ input_route(RIP_DEFAULT, 0, &new, n, RS_NOPROPAGATE); return; } if (!IS_IFF_ROUTING(ifp->int_if_flags)) { /* * We don't want to propagate routes which would * result in a black-hole. */ rt_state = RS_NOPROPAGATE; } do { if (n->n_family == RIP_AF_AUTH) continue; n->n_metric = ntohl(n->n_metric); dst = n->n_dst; if (n->n_family != RIP_AF_INET && (n->n_family != RIP_AF_UNSPEC || dst != RIP_DEFAULT)) { msglim(&bad_router, FROM_NADDR, "route from %s to unsupported" " address family=%d destination=%s", naddr_ntoa(FROM_NADDR), n->n_family, naddr_ntoa(dst)); continue; } if (!check_dst(dst)) { msglim(&bad_router, FROM_NADDR, "bad destination %s from %s", naddr_ntoa(dst), naddr_ntoa(FROM_NADDR)); continue; } if (n->n_metric == 0 || n->n_metric > HOPCNT_INFINITY) { msglim(&bad_router, FROM_NADDR, "bad metric %d from %s" " for destination %s", n->n_metric, naddr_ntoa(FROM_NADDR), naddr_ntoa(dst)); continue; } /* * Notice the next-hop. */ gate = FROM_NADDR; if (n->n_nhop != 0) { if (rip->rip_vers == RIPv1) { n->n_nhop = 0; } else { /* Use it only if it is valid. */ if (on_net(n->n_nhop, ifp->int_net, ifp->int_mask) && check_dst(n->n_nhop)) { gate = n->n_nhop; } else { msglim(&bad_nhop, FROM_NADDR, "router %s to %s" " has bad next hop %s", naddr_ntoa(FROM_NADDR), naddr_ntoa(dst), naddr_ntoa(n->n_nhop)); n->n_nhop = 0; } } } if (rip->rip_vers == RIPv1 || 0 == (mask = ntohl(n->n_mask))) { mask = ripv1_mask_host(dst, ifp); } else if ((ntohl(dst) & ~mask) != 0) { msglim(&bad_mask, FROM_NADDR, "router %s sent bad netmask %s with %s", naddr_ntoa(FROM_NADDR), naddr_ntoa(htonl(mask)), naddr_ntoa(dst)); continue; } if (mask == HOST_MASK && (ifp->int_state & IS_NO_HOST)) { trace_pkt(" ignored host route %s", addrname(dst, mask, 0)); continue; } if (rip->rip_vers == RIPv1) n->n_tag = 0; /* * Adjust metric according to incoming interface cost. * We intentionally don't drop incoming routes with * metric 15 on the floor even though they will * not be advertised to other routers. We can use * such routes locally, resulting in a network with * a maximum width of 15 hops rather than 14. */ n->n_metric += ifp->int_metric; if (n->n_metric > HOPCNT_INFINITY) n->n_metric = HOPCNT_INFINITY; /* * Should we trust this route from this router? */ if (tg != NULL && (tn = tg->tgate_nets)->mask != 0) { for (i = 0; i < MAX_TGATE_NETS; i++, tn++) { if (on_net(dst, tn->net, tn->mask) && tn->mask <= mask) break; } if (i >= MAX_TGATE_NETS || tn->mask == 0) { trace_pkt(" ignored unauthorized %s", addrname(dst, mask, 0)); continue; } } /* * Recognize and ignore a default route we faked * which is being sent back to us by a machine with * broken split-horizon. Be a little more paranoid * than that, and reject default routes with the * same metric we advertised. */ if (ifp->int_d_metric != 0 && dst == RIP_DEFAULT && n->n_metric >= ifp->int_d_metric) continue; /* * We can receive aggregated RIPv2 routes that must * be broken down before they are transmitted by * RIPv1 via an interface on a subnet. We might * also receive the same routes aggregated via * other RIPv2 interfaces. This could cause * duplicate routes to be sent on the RIPv1 * interfaces. "Longest matching variable length * netmasks" lets RIPv2 listeners understand, but * breaking down the aggregated routes for RIPv1 * listeners can produce duplicate routes. * * Breaking down aggregated routes here bloats the * daemon table, but does not hurt the kernel * table, since routes are always aggregated for * the kernel. * * Notice that this does not break down network * routes corresponding to subnets. This is part of * the defense against RS_NET_SYN. */ if (have_ripv1_out && (((rt = rtget(dst, mask)) == NULL || !(rt->rt_state & RS_NET_SYN))) && (v1_mask = ripv1_mask_net(dst, 0)) > mask) { /* Get least significant set bit */ ddst_h = v1_mask & -v1_mask; i = (v1_mask & ~mask)/ddst_h; /* * If you're going to make 512 or more * routes, then that's just too many. The * reason here is that breaking an old * class B into /24 allocations is common * enough that allowing for the creation of * at least 256 deaggregated routes is * good. The next power of 2 is 512. */ if (i >= 511) { /* * Punt if we would have to * generate an unreasonable number * of routes. */ if (TRACECONTENTS) trace_misc("accept %s-->%s as 1" " instead of %d routes", addrname(dst, mask, 0), naddr_ntoa(FROM_NADDR), i + 1); i = 0; } else { mask = v1_mask; } } else { i = 0; } new.rts_gate = gate; new.rts_router = FROM_NADDR; new.rts_metric = n->n_metric; new.rts_tag = n->n_tag; new.rts_time = now.tv_sec; new.rts_ifp = ifp; new.rts_de_ag = i; new.rts_origin = RO_RIP; j = 0; for (;;) { input_route(dst, mask, &new, n, rt_state); if (++j > i) break; dst = htonl(ntohl(dst) + ddst_h); } } while (++n < lim); return; case RIPCMD_POLLENTRY: /* * With this command one can request a single entry. * Both silent processes and routers can respond to this * command */ if (n >= lim) { msglim(&bad_len, FROM_NADDR, "empty request from %s", naddr_ntoa(FROM_NADDR)); return; } if (cc%sizeof (*n) != sizeof (struct rip)%sizeof (*n)) { msglim(&bad_len, FROM_NADDR, "request of bad length (%d) from %s", cc, naddr_ntoa(FROM_NADDR)); } if (rip->rip_vers == RIPv2 && (ifp == NULL || (ifp->int_state & IS_NO_RIPV1_OUT))) { v12buf.buf->rip_vers = RIPv2; } else { v12buf.buf->rip_vers = RIPv1; } /* Dont bother with md5 authentication with POLLENTRY */ ap = NULL; clr_ws_buf(&v12buf, ap); n->n_metric = ntohl(n->n_metric); if (n->n_family != RIP_AF_INET) { msglim(&bad_router, FROM_NADDR, "POLLENTRY request from %s for unsupported" " (af %d) %s", naddr_ntoa(FROM_NADDR), ntohs(n->n_family), naddr_ntoa(n->n_dst)); return; } /* We are being asked about a specific destination. */ v12buf.n->n_dst = dst = n->n_dst; v12buf.n->n_family = RIP_AF_INET; if (!check_dst(dst)) { msglim(&bad_router, FROM_NADDR, "bad queried destination %s from %s", naddr_ntoa(dst), naddr_ntoa(FROM_NADDR)); v12buf.n->n_metric = HOPCNT_INFINITY; goto pollentry_done; } /* decide what mask was intended */ if (rip->rip_vers == RIPv1 || 0 == (mask = ntohl(n->n_mask)) || 0 != (ntohl(dst) & ~mask)) mask = ripv1_mask_host(dst, ifp); /* try to find the answer */ rt = rtget(dst, mask); if (rt == NULL && dst != RIP_DEFAULT) rt = rtfind(n->n_dst); if (v12buf.buf->rip_vers != RIPv1) v12buf.n->n_mask = htonl(mask); if (rt == NULL) { /* we do not have the answer */ v12buf.n->n_metric = HOPCNT_INFINITY; goto pollentry_done; } /* * we have the answer, so compute the right metric and next * hop. */ v12buf.n->n_metric = rt->rt_metric + 1; if (v12buf.n->n_metric > HOPCNT_INFINITY) v12buf.n->n_metric = HOPCNT_INFINITY; if (v12buf.buf->rip_vers != RIPv1) { v12buf.n->n_tag = rt->rt_tag; if (ifp != NULL && on_net(rt->rt_gate, ifp->int_net, ifp->int_mask) && rt->rt_gate != ifp->int_addr) v12buf.n->n_nhop = rt->rt_gate; } pollentry_done: v12buf.n->n_metric = htonl(v12buf.n->n_metric); /* * Send the answer about specific routes. */ (void) output(OUT_QUERY, from, ifp, v12buf.buf, ((char *)v12buf.n - (char *)v12buf.buf)); break; } #undef FROM_NADDR } /* * Process a single input route. */ void input_route(in_addr_t dst, /* network order */ in_addr_t mask, struct rt_spare *new, struct netinfo *n, uint16_t rt_state) { int i; struct rt_entry *rt; struct rt_spare *rts, *rts0; struct interface *ifp1; struct rt_spare *ptr; size_t ptrsize; /* * See if we can already get there by a working interface. Ignore * if so. */ ifp1 = ifwithaddr(dst, _B_TRUE, _B_FALSE); if (ifp1 != NULL && (ifp1->int_state & IS_PASSIVE)) return; /* * Look for the route in our table. */ rt = rtget(dst, mask); /* Consider adding the route if we do not already have it. */ if (rt == NULL) { /* Ignore unknown routes being poisoned. */ if (new->rts_metric == HOPCNT_INFINITY) return; /* Ignore the route if it points to us */ if (n != NULL && n->n_nhop != 0 && NULL != ifwithaddr(n->n_nhop, _B_TRUE, _B_FALSE)) return; /* * If something has not gone crazy and tried to fill * our memory, accept the new route. */ rtadd(dst, mask, rt_state, new); return; } /* * We already know about the route. Consider this update. * * If (rt->rt_state & RS_NET_SYN), then this route * is the same as a network route we have inferred * for subnets we know, in order to tell RIPv1 routers * about the subnets. * * It is impossible to tell if the route is coming * from a distant RIPv2 router with the standard * netmask because that router knows about the entire * network, or if it is a round-about echo of a * synthetic, RIPv1 network route of our own. * The worst is that both kinds of routes might be * received, and the bad one might have the smaller * metric. Partly solve this problem by never * aggregating into such a route. Also keep it * around as long as the interface exists. */ rts0 = rt->rt_spares; trace_misc("rt 0x%lx num_spares %d", rt, rt->rt_num_spares); for (rts = rts0, i = rt->rt_num_spares; i != 0; i--, rts++) { if (rts->rts_router == new->rts_router) break; /* * Note the worst slot to reuse, * other than the current slot. */ if (BETTER_LINK(rt, rts0, rts)) rts0 = rts; } if (i != 0) { /* * Found a route from the router already in the table. */ /* * If the new route is a route broken down from an * aggregated route, and if the previous route is either * not a broken down route or was broken down from a finer * netmask, and if the previous route is current, * then forget this one. */ if (new->rts_de_ag > rts->rts_de_ag && now_stale <= rts->rts_time) return; /* * Keep poisoned routes around only long enough to pass * the poison on. Use a new timestamp for good routes. */ if (rts->rts_metric == HOPCNT_INFINITY && new->rts_metric == HOPCNT_INFINITY) new->rts_time = rts->rts_time; /* * If this is an update for the router we currently prefer, * then note it. */ if (i == rt->rt_num_spares) { rtchange(rt, rt->rt_state | rt_state, new, 0); /* * If the route got worse, check for something better. */ if (new->rts_metric != rts->rts_metric) rtswitch(rt, 0); return; } /* * This is an update for a spare route. * Finished if the route is unchanged. */ if (rts->rts_gate == new->rts_gate && rts->rts_metric == new->rts_metric && rts->rts_tag == new->rts_tag) { if ((rt->rt_dst == RIP_DEFAULT) && (rts->rts_ifp != new->rts_ifp)) trace_misc("input_route update for spare"); trace_upslot(rt, rts, new); *rts = *new; return; } /* * Forget it if it has gone bad. */ if (new->rts_metric == HOPCNT_INFINITY) { rts_delete(rt, rts); return; } } else { /* * The update is for a route we know about, * but not from a familiar router. * * Ignore the route if it points to us. */ if (n != NULL && n->n_nhop != 0 && NULL != ifwithaddr(n->n_nhop, _B_TRUE, _B_FALSE)) return; /* the loop above set rts0=worst spare */ if (rts0->rts_metric < HOPCNT_INFINITY) { ptrsize = (rt->rt_num_spares + SPARE_INC) * sizeof (struct rt_spare); ptr = realloc(rt->rt_spares, ptrsize); if (ptr != NULL) { rt->rt_spares = ptr; rts0 = &rt->rt_spares[rt->rt_num_spares]; (void) memset(rts0, 0, SPARE_INC * sizeof (struct rt_spare)); rt->rt_num_spares += SPARE_INC; for (rts = rts0, i = SPARE_INC; i != 0; i--, rts++) rts->rts_metric = HOPCNT_INFINITY; } } rts = rts0; /* * Save the route as a spare only if it has * a better metric than our worst spare. * This also ignores poisoned routes (those * received with metric HOPCNT_INFINITY). */ if (new->rts_metric >= rts->rts_metric) return; } trace_upslot(rt, rts, new); *rts = *new; /* try to switch to a better route */ rtswitch(rt, rts); } /* * Recorded information about peer's MD5 sequence numbers. This is * used to validate that received sequence numbers are in * non-decreasing order as per the RFC. */ struct peer_hash { struct peer_hash *ph_next; in_addr_t ph_addr; time_t ph_heard; uint32_t ph_seqno; }; static struct peer_hash **peer_hashes; static int ph_index; static int ph_num_peers; /* * Get a peer_hash structure from the hash of known peers. Create a * new one if not found. Returns NULL on unrecoverable allocation * failure. */ static struct peer_hash * get_peer_info(in_addr_t from) { struct peer_hash *php; struct peer_hash *pnhp; struct peer_hash **ph_pp; struct peer_hash **ph2_pp; struct peer_hash **ph3_pp; int i; static uint_t failed_count; if (peer_hashes == NULL) { peer_hashes = calloc(hash_table_sizes[0], sizeof (peer_hashes[0])); if (peer_hashes == NULL) { if (++failed_count % 100 == 1) msglog("no memory for peer hash"); return (NULL); } } /* Search for peer in existing hash table */ ph_pp = peer_hashes + (from % hash_table_sizes[ph_index]); for (php = ph_pp[0]; php != NULL; php = php->ph_next) { if (php->ph_addr == from) return (php); } /* * Not found; we need to add this peer to the table. If there * are already too many peers, then try to expand the table * first. It's not a big deal if we can't expand the table * right now due to memory constraints. We'll try again * later. */ if (ph_num_peers >= hash_table_sizes[ph_index] * 5 && hash_table_sizes[ph_index + 1] != 0 && (ph_pp = calloc(hash_table_sizes[ph_index + 1], sizeof (peer_hashes[0]))) != NULL) { ph2_pp = peer_hashes; for (i = hash_table_sizes[ph_index] - 1; i >= 0; i--) { for (php = ph2_pp[i]; php != NULL; php = pnhp) { pnhp = php->ph_next; ph3_pp = ph_pp + (php->ph_addr % hash_table_sizes[ph_index + 1]); php->ph_next = ph3_pp[0]; ph3_pp[0] = php; } } ph_index++; free(peer_hashes); peer_hashes = ph_pp; ph_pp += from % hash_table_sizes[ph_index]; } php = calloc(sizeof (*php), 1); if (php == NULL) { if (++failed_count % 100 == 1) msglog("no memory for peer hash entry"); } else { php->ph_addr = from; php->ph_heard = now.tv_sec; php->ph_next = ph_pp[0]; ph_pp[0] = php; ph_num_peers++; } return (php); } /* * Age out entries in the peer table. This is called every time we do * a normal 30 second broadcast. */ void age_peer_info(void) { struct peer_hash *php; struct peer_hash *next_ph; struct peer_hash *prev_ph; struct peer_hash **ph_pp; int i; /* * Scan through the list and remove peers that should not * still have valid authenticated entries in the routing * table. */ if ((ph_pp = peer_hashes) == NULL || ph_num_peers == 0) return; for (i = hash_table_sizes[ph_index] - 1; i >= 0; i--) { prev_ph = NULL; for (php = ph_pp[i]; php != NULL; php = next_ph) { next_ph = php->ph_next; if (php->ph_heard <= now_expire) { if (prev_ph == NULL) ph_pp[i] = next_ph; else prev_ph->ph_next = next_ph; free(php); if (--ph_num_peers == 0) return; } else { prev_ph = php; } } } } static boolean_t /* _B_FALSE if bad, _B_TRUE if good */ ck_passwd(struct interface *aifp, struct rip *rip, uint8_t *lim, in_addr_t from, struct msg_limit *use_authp) { #define NA (rip->rip_auths) struct netauth *na2; struct auth *ap; MD5_CTX md5_ctx; uchar_t hash[RIP_AUTH_PW_LEN]; int i, len; struct peer_hash *php; uint32_t seqno; if ((uint8_t *)NA >= lim || NA->a_family != RIP_AF_AUTH) { msglim(use_authp, from, "missing auth data from %s", naddr_ntoa(from)); return (_B_FALSE); } /* * Validate sequence number on RIPv2 responses using keyed MD5 * authentication per RFC 2082 section 3.2.2. Note that if we * can't locate the peer information (due to transient * allocation problems), then we don't do the test. Also note * that we assume that all sequence numbers 0x80000000 or more * away are "less than." * * We intentionally violate RFC 2082 with respect to one case: * restablishing contact. The RFC says that you should * continue to ignore old sequence numbers in this case but * make a special allowance for 0. This is extremely foolish. * The problem is that if the router has crashed, it's * entirely possible that either we'll miss sequence zero (or * that it might not even send it!) or that the peer doesn't * remember what it last used for a sequence number. In * either case, we'll create a failure state that persists * until the sequence number happens to advance past the last * one we saw. This is bad because it means that we may have * to wait until the router has been up for at least as long * as it was last time before we even pay attention to it. * Meanwhile, other routers may listen to it if they hadn't * seen it before (i.e., if they crashed in the meantime). * This means -- perversely -- that stable systems that stay * "up" for a long time pay a penalty for doing so. */ if (rip->rip_cmd == RIPCMD_RESPONSE && NA->a_type == RIP_AUTH_MD5 && (php = get_peer_info(from)) != NULL) { /* * If the entry that we find has been updated * recently enough that the routes are known * to still be good, but the sequence number * looks bad, then discard the packet. */ seqno = ntohl(NA->au.a_md5.md5_seqno); if (php->ph_heard > now_expire && php->ph_seqno != 0 && (seqno == 0 || ((seqno - php->ph_seqno) & 0x80000000ul))) { msglim(use_authp, from, "discarding sequence %x (older than %x)", (unsigned)seqno, (unsigned)php->ph_seqno); return (_B_FALSE); } php->ph_heard = now.tv_sec; php->ph_seqno = seqno; } /* * accept any current (+/- 24 hours) password */ for (ap = aifp->int_auth, i = 0; i < MAX_AUTH_KEYS; i++, ap++) { if (ap->type != NA->a_type || (ulong_t)ap->start > (ulong_t)clk.tv_sec+DAY || (ulong_t)ap->end+DAY < (ulong_t)clk.tv_sec) continue; if (NA->a_type == RIP_AUTH_PW) { if (0 == memcmp(NA->au.au_pw, ap->key, RIP_AUTH_PW_LEN)) return (_B_TRUE); } else { /* * accept MD5 secret with the right key ID */ if (NA->au.a_md5.md5_keyid != ap->keyid) continue; len = ntohs(NA->au.a_md5.md5_pkt_len); if ((len - sizeof (*rip)) % sizeof (*NA) != 0 || len > (lim - (uint8_t *)rip - sizeof (*NA))) { msglim(use_authp, from, "wrong MD5 RIPv2 packet length of %d" " instead of %d from %s", len, lim - (uint8_t *)rip - sizeof (*NA), naddr_ntoa(from)); return (_B_FALSE); } na2 = (struct netauth *)(rip->rip_nets + (len - 4) / sizeof (struct netinfo)); /* * Given a good hash value, these are not security * problems so be generous and accept the routes, * after complaining. */ if (TRACEPACKETS) { if (NA->au.a_md5.md5_auth_len != RIP_AUTH_MD5_LEN) msglim(use_authp, from, "unknown MD5 RIPv2 auth len %#x" " instead of %#x from %s", NA->au.a_md5.md5_auth_len, RIP_AUTH_MD5_LEN, naddr_ntoa(from)); if (na2->a_family != RIP_AF_AUTH) msglim(use_authp, from, "unknown MD5 RIPv2 family %#x" " instead of %#x from %s", na2->a_family, RIP_AF_AUTH, naddr_ntoa(from)); if (na2->a_type != RIP_AUTH_TRAILER) msglim(use_authp, from, "MD5 RIPv2 hash has %#x" " instead of %#x from %s", ntohs(na2->a_type), ntohs(RIP_AUTH_TRAILER), naddr_ntoa(from)); } MD5Init(&md5_ctx); /* * len+4 to include auth trailer's family/type in * MD5 sum */ MD5Update(&md5_ctx, (uchar_t *)rip, len + 4); MD5Update(&md5_ctx, ap->key, RIP_AUTH_MD5_LEN); MD5Final(hash, &md5_ctx); if (0 == memcmp(hash, na2->au.au_pw, sizeof (hash))) return (_B_TRUE); } } msglim(use_authp, from, "bad auth data from %s", naddr_ntoa(from)); return (_B_FALSE); #undef NA }