118316Swollman/* 218316Swollman * Copyright (c) 1983, 1988, 1993 318316Swollman * The Regents of the University of California. All rights reserved. 418316Swollman * 518316Swollman * Redistribution and use in source and binary forms, with or without 618316Swollman * modification, are permitted provided that the following conditions 718316Swollman * are met: 818316Swollman * 1. Redistributions of source code must retain the above copyright 918316Swollman * notice, this list of conditions and the following disclaimer. 1018316Swollman * 2. Redistributions in binary form must reproduce the above copyright 1118316Swollman * notice, this list of conditions and the following disclaimer in the 1218316Swollman * documentation and/or other materials provided with the distribution. 1318316Swollman * 4. Neither the name of the University nor the names of its contributors 1418316Swollman * may be used to endorse or promote products derived from this software 1518316Swollman * without specific prior written permission. 1618316Swollman * 1718316Swollman * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 1818316Swollman * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 1918316Swollman * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 2018316Swollman * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 2118316Swollman * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 2218316Swollman * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2318316Swollman * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2418316Swollman * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2518316Swollman * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2618316Swollman * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 2718316Swollman * SUCH DAMAGE. 2846303Smarkm * 2950476Speter * $FreeBSD$ 3018316Swollman */ 3118316Swollman 3246303Smarkm#include "defs.h" 3346303Smarkm 34126250Sbms#ifdef __NetBSD__ 3546303Smarkm__RCSID("$NetBSD$"); 36126250Sbms#elif defined(__FreeBSD__) 37126250Sbms__RCSID("$FreeBSD$"); 38126250Sbms#else 39126250Sbms__RCSID("$Revision: 2.26 $"); 40126250Sbms#ident "$Revision: 2.26 $" 4118316Swollman#endif 4218316Swollman 4319880Swollmanstatic void input(struct sockaddr_in *, struct interface *, struct interface *, 4419880Swollman struct rip *, int); 4546303Smarkmstatic void input_route(naddr, naddr, struct rt_spare *, struct netinfo *); 4619880Swollmanstatic int ck_passwd(struct interface *, struct rip *, void *, 4719880Swollman naddr, struct msg_limit *); 4818316Swollman 4918316Swollman 5018316Swollman/* process RIP input 5118316Swollman */ 5218316Swollmanvoid 5318316Swollmanread_rip(int sock, 5419880Swollman struct interface *sifp) 5518316Swollman{ 5618316Swollman struct sockaddr_in from; 5719880Swollman struct interface *aifp; 58148726Sstefanf socklen_t fromlen; 59148726Sstefanf int cc; 6020339Swollman#ifdef USE_PASSIFNAME 6120339Swollman static struct msg_limit bad_name; 6219880Swollman struct { 6319880Swollman char ifname[IFNAMSIZ]; 6419880Swollman union pkt_buf pbuf; 6519880Swollman } inbuf; 6620339Swollman#else 6720339Swollman struct { 6820339Swollman union pkt_buf pbuf; 6920339Swollman } inbuf; 7020339Swollman#endif 7118316Swollman 7218316Swollman 7318316Swollman for (;;) { 7418316Swollman fromlen = sizeof(from); 7518316Swollman cc = recvfrom(sock, &inbuf, sizeof(inbuf), 0, 7618316Swollman (struct sockaddr*)&from, &fromlen); 7718316Swollman if (cc <= 0) { 7818316Swollman if (cc < 0 && errno != EWOULDBLOCK) 7918316Swollman LOGERR("recvfrom(rip)"); 8018316Swollman break; 8118316Swollman } 8218316Swollman if (fromlen != sizeof(struct sockaddr_in)) 8318316Swollman logbad(1,"impossible recvfrom(rip) fromlen=%d", 84148726Sstefanf (int)fromlen); 8518316Swollman 8619880Swollman /* aifp is the "authenticated" interface via which the packet 8719880Swollman * arrived. In fact, it is only the interface on which 8819880Swollman * the packet should have arrived based on is source 8919880Swollman * address. 9019880Swollman * sifp is interface associated with the socket through which 9119880Swollman * the packet was received. 9219880Swollman */ 9319880Swollman#ifdef USE_PASSIFNAME 9419880Swollman if ((cc -= sizeof(inbuf.ifname)) < 0) 9519880Swollman logbad(0,"missing USE_PASSIFNAME; only %d bytes", 9619880Swollman cc+sizeof(inbuf.ifname)); 9719880Swollman 9819880Swollman /* check the remote interfaces first */ 99190713Sphk LIST_FOREACH(aifp, &remote_if, remote_list) { 10019880Swollman if (aifp->int_addr == from.sin_addr.s_addr) 10119880Swollman break; 10219880Swollman } 10319880Swollman if (aifp == 0) { 10419880Swollman aifp = ifwithname(inbuf.ifname, 0); 10519880Swollman if (aifp == 0) { 10620606Swollman msglim(&bad_name, from.sin_addr.s_addr, 10720606Swollman "impossible interface name %.*s", 10820606Swollman IFNAMSIZ, inbuf.ifname); 10920606Swollman } else if (((aifp->int_if_flags & IFF_POINTOPOINT) 11020606Swollman && aifp->int_dstaddr!=from.sin_addr.s_addr) 11120606Swollman || (!(aifp->int_if_flags & IFF_POINTOPOINT) 11220606Swollman && !on_net(from.sin_addr.s_addr, 11320606Swollman aifp->int_net, 11420606Swollman aifp->int_mask))) { 11520606Swollman /* If it came via the wrong interface, do not 11620606Swollman * trust it. 11720606Swollman */ 11820606Swollman aifp = 0; 11919880Swollman } 12019880Swollman } 12119880Swollman#else 12219880Swollman aifp = iflookup(from.sin_addr.s_addr); 12319880Swollman#endif 12419880Swollman if (sifp == 0) 12519880Swollman sifp = aifp; 12619880Swollman 12719880Swollman input(&from, sifp, aifp, &inbuf.pbuf.rip, cc); 12818316Swollman } 12918316Swollman} 13018316Swollman 13118316Swollman 13218316Swollman/* Process a RIP packet 13318316Swollman */ 13418316Swollmanstatic void 13518316Swollmaninput(struct sockaddr_in *from, /* received from this IP address */ 13619880Swollman struct interface *sifp, /* interface of incoming socket */ 13719880Swollman struct interface *aifp, /* "authenticated" interface */ 13818316Swollman struct rip *rip, 13919880Swollman int cc) 14018316Swollman{ 14118316Swollman# define FROM_NADDR from->sin_addr.s_addr 14219880Swollman static struct msg_limit use_auth, bad_len, bad_mask; 14346303Smarkm static struct msg_limit unk_router, bad_router, bad_nhop; 14418316Swollman 14518316Swollman struct rt_entry *rt; 14646303Smarkm struct rt_spare new; 14718316Swollman struct netinfo *n, *lim; 14818316Swollman struct interface *ifp1; 14946303Smarkm naddr gate, mask, v1_mask, dst, ddst_h = 0; 15020339Swollman struct auth *ap; 15146303Smarkm struct tgate *tg = 0; 15246303Smarkm struct tgate_net *tn; 15346303Smarkm int i, j; 15418316Swollman 15519880Swollman /* Notice when we hear from a remote gateway 15619880Swollman */ 15719880Swollman if (aifp != 0 15819880Swollman && (aifp->int_state & IS_REMOTE)) 15919880Swollman aifp->int_act_time = now.tv_sec; 16018316Swollman 16119880Swollman trace_rip("Recv", "from", from, sifp, rip, cc); 16218316Swollman 163286351Sdelphij if (sifp == 0) { 164286351Sdelphij trace_pkt(" discard a request from an indirect router" 165286351Sdelphij " (possibly an attack)"); 166286351Sdelphij return; 167286351Sdelphij } 168286351Sdelphij 16918316Swollman if (rip->rip_vers == 0) { 17019880Swollman msglim(&bad_router, FROM_NADDR, 17119880Swollman "RIP version 0, cmd %d, packet received from %s", 17219880Swollman rip->rip_cmd, naddr_ntoa(FROM_NADDR)); 17318316Swollman return; 17418316Swollman } else if (rip->rip_vers > RIPv2) { 17518316Swollman rip->rip_vers = RIPv2; 17618316Swollman } 17746303Smarkm if (cc > (int)OVER_MAXPACKETSIZE) { 17819880Swollman msglim(&bad_router, FROM_NADDR, 17919880Swollman "packet at least %d bytes too long received from %s", 18019880Swollman cc-MAXPACKETSIZE, naddr_ntoa(FROM_NADDR)); 18118316Swollman return; 18218316Swollman } 18318316Swollman 18418316Swollman n = rip->rip_nets; 18519880Swollman lim = (struct netinfo *)((char*)rip + cc); 18618316Swollman 18718316Swollman /* Notice authentication. 18818316Swollman * As required by section 4.2 in RFC 1723, discard authenticated 18918316Swollman * RIPv2 messages, but only if configured for that silliness. 19018316Swollman * 19119880Swollman * RIPv2 authentication is lame. Why authenticate queries? 19218316Swollman * Why should a RIPv2 implementation with authentication disabled 19337908Scharnier * not be able to listen to RIPv2 packets with authentication, while 19418316Swollman * RIPv1 systems will listen? Crazy! 19518316Swollman */ 19618316Swollman if (!auth_ok 19718316Swollman && rip->rip_vers == RIPv2 19818316Swollman && n < lim && n->n_family == RIP_AF_AUTH) { 19919880Swollman msglim(&use_auth, FROM_NADDR, 20019880Swollman "RIPv2 message with authentication from %s discarded", 20119880Swollman naddr_ntoa(FROM_NADDR)); 20218316Swollman return; 20318316Swollman } 20418316Swollman 20518316Swollman switch (rip->rip_cmd) { 20618316Swollman case RIPCMD_REQUEST: 20719880Swollman /* For mere requests, be a little sloppy about the source 20818316Swollman */ 20919880Swollman if (aifp == 0) 21019880Swollman aifp = sifp; 21119880Swollman 21219880Swollman /* Are we talking to ourself or a remote gateway? 21319880Swollman */ 21419880Swollman ifp1 = ifwithaddr(FROM_NADDR, 0, 1); 21519880Swollman if (ifp1) { 21619880Swollman if (ifp1->int_state & IS_REMOTE) { 21719880Swollman /* remote gateway */ 21819880Swollman aifp = ifp1; 21919880Swollman if (check_remote(aifp)) { 22019880Swollman aifp->int_act_time = now.tv_sec; 22119880Swollman (void)if_ok(aifp, "remote "); 22219880Swollman } 22319880Swollman } else if (from->sin_port == htons(RIP_PORT)) { 22419880Swollman trace_pkt(" discard our own RIP request"); 22518316Swollman return; 22618316Swollman } 22719880Swollman } 22818316Swollman 22919880Swollman /* did the request come from a router? 23019880Swollman */ 23119880Swollman if (from->sin_port == htons(RIP_PORT)) { 23219880Swollman /* yes, ignore the request if RIP is off so that 23319880Swollman * the router does not depend on us. 23418316Swollman */ 23519880Swollman if (rip_sock < 0 23619880Swollman || (aifp != 0 23719880Swollman && IS_RIP_OUT_OFF(aifp->int_state))) { 23819880Swollman trace_pkt(" discard request while RIP off"); 23918316Swollman return; 24018316Swollman } 24118316Swollman } 24218316Swollman 24337908Scharnier /* According to RFC 1723, we should ignore unauthenticated 24418316Swollman * queries. That is too silly to bother with. Sheesh! 24519880Swollman * Are forwarding tables supposed to be secret, when 24619880Swollman * a bad guy can infer them with test traffic? When RIP 24719880Swollman * is still the most common router-discovery protocol 24819880Swollman * and so hosts need to send queries that will be answered? 24919880Swollman * What about `rtquery`? 25018316Swollman * Maybe on firewalls you'd care, but not enough to 25118316Swollman * give up the diagnostic facilities of remote probing. 25218316Swollman */ 25318316Swollman 25419880Swollman if (n >= lim) { 25519880Swollman msglim(&bad_len, FROM_NADDR, "empty request from %s", 25619880Swollman naddr_ntoa(FROM_NADDR)); 25719880Swollman return; 25818316Swollman } 25919880Swollman if (cc%sizeof(*n) != sizeof(struct rip)%sizeof(*n)) { 26019880Swollman msglim(&bad_len, FROM_NADDR, 26119880Swollman "request of bad length (%d) from %s", 26219880Swollman cc, naddr_ntoa(FROM_NADDR)); 26319880Swollman } 26418316Swollman 26519880Swollman if (rip->rip_vers == RIPv2 26619880Swollman && (aifp == 0 || (aifp->int_state & IS_NO_RIPV1_OUT))) { 26719880Swollman v12buf.buf->rip_vers = RIPv2; 26819880Swollman /* If we have a secret but it is a cleartext secret, 26919880Swollman * do not disclose our secret unless the other guy 27019880Swollman * already knows it. 27119880Swollman */ 27220339Swollman ap = find_auth(aifp); 27320735Sache if (ap != 0 && ap->type == RIP_AUTH_PW 27420339Swollman && n->n_family == RIP_AF_AUTH 27519880Swollman && !ck_passwd(aifp,rip,lim,FROM_NADDR,&use_auth)) 27619880Swollman ap = 0; 27719880Swollman } else { 27819880Swollman v12buf.buf->rip_vers = RIPv1; 27919880Swollman ap = 0; 28019880Swollman } 28120339Swollman clr_ws_buf(&v12buf, ap); 28219880Swollman 28319880Swollman do { 28490868Smike n->n_metric = ntohl(n->n_metric); 28519880Swollman 28618316Swollman /* A single entry with family RIP_AF_UNSPEC and 28718316Swollman * metric HOPCNT_INFINITY means "all routes". 28818316Swollman * We respond to routers only if we are acting 28918316Swollman * as a supplier, or to anyone other than a router 29018316Swollman * (i.e. a query). 29118316Swollman */ 29218316Swollman if (n->n_family == RIP_AF_UNSPEC 29319880Swollman && n->n_metric == HOPCNT_INFINITY) { 29446303Smarkm /* Answer a query from a utility program 29546303Smarkm * with all we know. 29646303Smarkm */ 297273414Sdelphij if (aifp == NULL) { 298273414Sdelphij trace_pkt("ignore remote query"); 299273414Sdelphij return; 300273414Sdelphij } 30118316Swollman if (from->sin_port != htons(RIP_PORT)) { 30219880Swollman supply(from, aifp, OUT_QUERY, 0, 30319880Swollman rip->rip_vers, ap != 0); 30418316Swollman return; 30518316Swollman } 30619880Swollman 30718316Swollman /* A router trying to prime its tables. 30818316Swollman * Filter the answer in the about same way 30918316Swollman * broadcasts are filtered. 31018316Swollman * 31118316Swollman * Only answer a router if we are a supplier 31218316Swollman * to keep an unwary host that is just starting 31346303Smarkm * from picking us as a router. 31418316Swollman */ 31519880Swollman if (aifp == 0) { 31619880Swollman trace_pkt("ignore distant router"); 31719880Swollman return; 31819880Swollman } 31918316Swollman if (!supplier 32019880Swollman || IS_RIP_OFF(aifp->int_state)) { 32119880Swollman trace_pkt("ignore; not supplying"); 32218316Swollman return; 32319880Swollman } 32418316Swollman 32546303Smarkm /* Do not answer a RIPv1 router if 32646303Smarkm * we are sending RIPv2. But do offer 32746303Smarkm * poor man's router discovery. 32846303Smarkm */ 32946303Smarkm if ((aifp->int_state & IS_NO_RIPV1_OUT) 33046303Smarkm && rip->rip_vers == RIPv1) { 33146303Smarkm if (!(aifp->int_state & IS_PM_RDISC)) { 33246303Smarkm trace_pkt("ignore; sending RIPv2"); 33346303Smarkm return; 33446303Smarkm } 33546303Smarkm 33646303Smarkm v12buf.n->n_family = RIP_AF_INET; 33746303Smarkm v12buf.n->n_dst = RIP_DEFAULT; 33846303Smarkm i = aifp->int_d_metric; 339126250Sbms if (0 != (rt = rtget(RIP_DEFAULT, 0))) { 340126250Sbms j = (rt->rt_metric 341126250Sbms +aifp->int_metric 342126250Sbms +aifp->int_adj_outmetric 343126250Sbms +1); 344126250Sbms if (i > j) 345126250Sbms i = j; 346126250Sbms } 34746303Smarkm v12buf.n->n_metric = htonl(i); 34846303Smarkm v12buf.n++; 34946303Smarkm break; 35046303Smarkm } 35146303Smarkm 35246303Smarkm /* Respond with RIPv1 instead of RIPv2 if 35346303Smarkm * that is what we are broadcasting on the 35446303Smarkm * interface to keep the remote router from 35546303Smarkm * getting the wrong initial idea of the 35646303Smarkm * routes we send. 35746303Smarkm */ 35818316Swollman supply(from, aifp, OUT_UNICAST, 0, 35946303Smarkm (aifp->int_state & IS_NO_RIPV1_OUT) 36019880Swollman ? RIPv2 : RIPv1, 36119880Swollman ap != 0); 36218316Swollman return; 36318316Swollman } 36418316Swollman 36519880Swollman /* Ignore authentication */ 36619880Swollman if (n->n_family == RIP_AF_AUTH) 36719880Swollman continue; 36819880Swollman 36918316Swollman if (n->n_family != RIP_AF_INET) { 37019880Swollman msglim(&bad_router, FROM_NADDR, 37146303Smarkm "request from %s for unsupported" 37246303Smarkm " (af %d) %s", 37319880Swollman naddr_ntoa(FROM_NADDR), 37419880Swollman ntohs(n->n_family), 37519880Swollman naddr_ntoa(n->n_dst)); 37618316Swollman return; 37718316Swollman } 37818316Swollman 37919880Swollman /* We are being asked about a specific destination. 38019880Swollman */ 38118316Swollman dst = n->n_dst; 38218316Swollman if (!check_dst(dst)) { 38319880Swollman msglim(&bad_router, FROM_NADDR, 38419880Swollman "bad queried destination %s from %s", 38519880Swollman naddr_ntoa(dst), 38619880Swollman naddr_ntoa(FROM_NADDR)); 38718316Swollman return; 38818316Swollman } 38918316Swollman 39019880Swollman /* decide what mask was intended */ 39118316Swollman if (rip->rip_vers == RIPv1 39218316Swollman || 0 == (mask = ntohl(n->n_mask)) 39318316Swollman || 0 != (ntohl(dst) & ~mask)) 39419880Swollman mask = ripv1_mask_host(dst, aifp); 39518316Swollman 39619880Swollman /* try to find the answer */ 39718316Swollman rt = rtget(dst, mask); 39818316Swollman if (!rt && dst != RIP_DEFAULT) 39918316Swollman rt = rtfind(n->n_dst); 40018316Swollman 40119880Swollman if (v12buf.buf->rip_vers != RIPv1) 40219880Swollman v12buf.n->n_mask = mask; 40318316Swollman if (rt == 0) { 40419880Swollman /* we do not have the answer */ 40519880Swollman v12buf.n->n_metric = HOPCNT_INFINITY; 40618316Swollman } else { 40719880Swollman /* we have the answer, so compute the 40819880Swollman * right metric and next hop. 40919880Swollman */ 41019880Swollman v12buf.n->n_family = RIP_AF_INET; 41119880Swollman v12buf.n->n_dst = dst; 412126250Sbms j = rt->rt_metric+1; 413126250Sbms if (!aifp) 414126250Sbms ++j; 415126250Sbms else 416126250Sbms j += (aifp->int_metric 417126250Sbms + aifp->int_adj_outmetric); 418126250Sbms if (j < HOPCNT_INFINITY) 419126250Sbms v12buf.n->n_metric = j; 420126250Sbms else 42119880Swollman v12buf.n->n_metric = HOPCNT_INFINITY; 42219880Swollman if (v12buf.buf->rip_vers != RIPv1) { 42319880Swollman v12buf.n->n_tag = rt->rt_tag; 42419880Swollman v12buf.n->n_mask = mask; 42519880Swollman if (aifp != 0 42618316Swollman && on_net(rt->rt_gate, 42719880Swollman aifp->int_net, 42819880Swollman aifp->int_mask) 42919880Swollman && rt->rt_gate != aifp->int_addr) 43019880Swollman v12buf.n->n_nhop = rt->rt_gate; 43118316Swollman } 43218316Swollman } 43390868Smike v12buf.n->n_metric = htonl(v12buf.n->n_metric); 43419880Swollman 43519880Swollman /* Stop paying attention if we fill the output buffer. 43619880Swollman */ 43719880Swollman if (++v12buf.n >= v12buf.lim) 43819880Swollman break; 43919880Swollman } while (++n < lim); 44019880Swollman 44119880Swollman /* Send the answer about specific routes. 44218316Swollman */ 44320339Swollman if (ap != 0 && ap->type == RIP_AUTH_MD5) 44419880Swollman end_md5_auth(&v12buf, ap); 44519880Swollman 44618316Swollman if (from->sin_port != htons(RIP_PORT)) { 44718316Swollman /* query */ 44819880Swollman (void)output(OUT_QUERY, from, aifp, 44919880Swollman v12buf.buf, 45019880Swollman ((char *)v12buf.n - (char*)v12buf.buf)); 45118316Swollman } else if (supplier) { 45219880Swollman (void)output(OUT_UNICAST, from, aifp, 45319880Swollman v12buf.buf, 45419880Swollman ((char *)v12buf.n - (char*)v12buf.buf)); 45519880Swollman } else { 45619880Swollman /* Only answer a router if we are a supplier 45719880Swollman * to keep an unwary host that is just starting 45819880Swollman * from picking us an a router. 45919880Swollman */ 46019880Swollman ; 46118316Swollman } 46218316Swollman return; 46318316Swollman 46418316Swollman case RIPCMD_TRACEON: 46518316Swollman case RIPCMD_TRACEOFF: 46646303Smarkm /* Notice that trace messages are turned off for all possible 46746303Smarkm * abuse if _PATH_TRACE is undefined in pathnames.h. 46846303Smarkm * Notice also that because of the way the trace file is 46946303Smarkm * handled in trace.c, no abuse is plausible even if 47046303Smarkm * _PATH_TRACE_ is defined. 47146303Smarkm * 47246303Smarkm * First verify message came from a privileged port. */ 47318316Swollman if (ntohs(from->sin_port) > IPPORT_RESERVED) { 47418316Swollman msglog("trace command from untrusted port on %s", 47518316Swollman naddr_ntoa(FROM_NADDR)); 47618316Swollman return; 47718316Swollman } 47818316Swollman if (aifp == 0) { 47918316Swollman msglog("trace command from unknown router %s", 48018316Swollman naddr_ntoa(FROM_NADDR)); 48118316Swollman return; 48218316Swollman } 48318316Swollman if (rip->rip_cmd == RIPCMD_TRACEON) { 48419880Swollman rip->rip_tracefile[cc-4] = '\0'; 48520339Swollman set_tracefile((char*)rip->rip_tracefile, 48620339Swollman "trace command: %s\n", 0); 48718316Swollman } else { 48846303Smarkm trace_off("tracing turned off by %s", 48918316Swollman naddr_ntoa(FROM_NADDR)); 49018316Swollman } 49118316Swollman return; 49218316Swollman 49318316Swollman case RIPCMD_RESPONSE: 49419880Swollman if (cc%sizeof(*n) != sizeof(struct rip)%sizeof(*n)) { 49519880Swollman msglim(&bad_len, FROM_NADDR, 49619880Swollman "response of bad length (%d) from %s", 49719880Swollman cc, naddr_ntoa(FROM_NADDR)); 49818316Swollman } 49918316Swollman 50018316Swollman /* verify message came from a router */ 50118316Swollman if (from->sin_port != ntohs(RIP_PORT)) { 50219880Swollman msglim(&bad_router, FROM_NADDR, 50319880Swollman " discard RIP response from unknown port" 504126250Sbms " %d on %s", 505126250Sbms ntohs(from->sin_port), naddr_ntoa(FROM_NADDR)); 50618316Swollman return; 50718316Swollman } 50818316Swollman 50918316Swollman if (rip_sock < 0) { 51019880Swollman trace_pkt(" discard response while RIP off"); 51118316Swollman return; 51218316Swollman } 51318316Swollman 51418316Swollman /* Are we talking to ourself or a remote gateway? 51518316Swollman */ 51618316Swollman ifp1 = ifwithaddr(FROM_NADDR, 0, 1); 51718316Swollman if (ifp1) { 51818316Swollman if (ifp1->int_state & IS_REMOTE) { 51919880Swollman /* remote gateway */ 52019880Swollman aifp = ifp1; 52119880Swollman if (check_remote(aifp)) { 52219880Swollman aifp->int_act_time = now.tv_sec; 52319880Swollman (void)if_ok(aifp, "remote "); 52418316Swollman } 52518316Swollman } else { 52619880Swollman trace_pkt(" discard our own RIP response"); 52719880Swollman return; 52818316Swollman } 52918316Swollman } 53018316Swollman 53119880Swollman /* Accept routing packets from routers directly connected 53219880Swollman * via broadcast or point-to-point networks, and from 53318316Swollman * those listed in /etc/gateways. 53418316Swollman */ 53519880Swollman if (aifp == 0) { 53619880Swollman msglim(&unk_router, FROM_NADDR, 53719880Swollman " discard response from %s" 53819880Swollman " via unexpected interface", 53919880Swollman naddr_ntoa(FROM_NADDR)); 54018316Swollman return; 54118316Swollman } 54219880Swollman if (IS_RIP_IN_OFF(aifp->int_state)) { 54319880Swollman trace_pkt(" discard RIPv%d response" 54419880Swollman " via disabled interface %s", 54519880Swollman rip->rip_vers, aifp->int_name); 54618316Swollman return; 54718316Swollman } 54818316Swollman 54919880Swollman if (n >= lim) { 55019880Swollman msglim(&bad_len, FROM_NADDR, "empty response from %s", 55119880Swollman naddr_ntoa(FROM_NADDR)); 55219880Swollman return; 55319880Swollman } 55419880Swollman 55518316Swollman if (((aifp->int_state & IS_NO_RIPV1_IN) 55618316Swollman && rip->rip_vers == RIPv1) 55718316Swollman || ((aifp->int_state & IS_NO_RIPV2_IN) 55818316Swollman && rip->rip_vers != RIPv1)) { 55919880Swollman trace_pkt(" discard RIPv%d response", 56018316Swollman rip->rip_vers); 56118316Swollman return; 56218316Swollman } 56318316Swollman 56418316Swollman /* Ignore routes via dead interface. 56518316Swollman */ 56618316Swollman if (aifp->int_state & IS_BROKE) { 56746303Smarkm trace_pkt("discard response via broken interface %s", 56818316Swollman aifp->int_name); 56918316Swollman return; 57018316Swollman } 57118316Swollman 57219880Swollman /* If the interface cares, ignore bad routers. 57320339Swollman * Trace but do not log this problem, because where it 57420339Swollman * happens, it happens frequently. 57519880Swollman */ 57619880Swollman if (aifp->int_state & IS_DISTRUST) { 57746303Smarkm tg = tgates; 57819880Swollman while (tg->tgate_addr != FROM_NADDR) { 57919880Swollman tg = tg->tgate_next; 58019880Swollman if (tg == 0) { 58119880Swollman trace_pkt(" discard RIP response" 58219880Swollman " from untrusted router %s", 58319880Swollman naddr_ntoa(FROM_NADDR)); 58419880Swollman return; 58519880Swollman } 58619880Swollman } 58719880Swollman } 58819880Swollman 58918316Swollman /* Authenticate the packet if we have a secret. 59020339Swollman * If we do not have any secrets, ignore the error in 59120339Swollman * RFC 1723 and accept it regardless. 59218316Swollman */ 59320339Swollman if (aifp->int_auth[0].type != RIP_AUTH_NONE 59420339Swollman && rip->rip_vers != RIPv1 59520339Swollman && !ck_passwd(aifp,rip,lim,FROM_NADDR,&use_auth)) 59620339Swollman return; 59718316Swollman 59819880Swollman do { 59918316Swollman if (n->n_family == RIP_AF_AUTH) 60018316Swollman continue; 60118316Swollman 60290868Smike n->n_metric = ntohl(n->n_metric); 60318316Swollman dst = n->n_dst; 60418316Swollman if (n->n_family != RIP_AF_INET 60518316Swollman && (n->n_family != RIP_AF_UNSPEC 60618316Swollman || dst != RIP_DEFAULT)) { 60719880Swollman msglim(&bad_router, FROM_NADDR, 60819880Swollman "route from %s to unsupported" 60919880Swollman " address family=%d destination=%s", 61019880Swollman naddr_ntoa(FROM_NADDR), 61119880Swollman n->n_family, 61219880Swollman naddr_ntoa(dst)); 61318316Swollman continue; 61418316Swollman } 61518316Swollman if (!check_dst(dst)) { 61619880Swollman msglim(&bad_router, FROM_NADDR, 61719880Swollman "bad destination %s from %s", 61819880Swollman naddr_ntoa(dst), 61919880Swollman naddr_ntoa(FROM_NADDR)); 62018316Swollman return; 62118316Swollman } 62218316Swollman if (n->n_metric == 0 62318316Swollman || n->n_metric > HOPCNT_INFINITY) { 62419880Swollman msglim(&bad_router, FROM_NADDR, 62519880Swollman "bad metric %d from %s" 62619880Swollman " for destination %s", 62719880Swollman n->n_metric, 62819880Swollman naddr_ntoa(FROM_NADDR), 62919880Swollman naddr_ntoa(dst)); 63018316Swollman return; 63118316Swollman } 63218316Swollman 63318316Swollman /* Notice the next-hop. 63418316Swollman */ 63519880Swollman gate = FROM_NADDR; 63618316Swollman if (n->n_nhop != 0) { 63746303Smarkm if (rip->rip_vers == RIPv1) { 63818316Swollman n->n_nhop = 0; 63918316Swollman } else { 64018316Swollman /* Use it only if it is valid. */ 64118316Swollman if (on_net(n->n_nhop, 64218316Swollman aifp->int_net, aifp->int_mask) 64318316Swollman && check_dst(n->n_nhop)) { 64418316Swollman gate = n->n_nhop; 64518316Swollman } else { 64619880Swollman msglim(&bad_nhop, FROM_NADDR, 64719880Swollman "router %s to %s" 64819880Swollman " has bad next hop %s", 64919880Swollman naddr_ntoa(FROM_NADDR), 65019880Swollman naddr_ntoa(dst), 65119880Swollman naddr_ntoa(n->n_nhop)); 65219880Swollman n->n_nhop = 0; 65318316Swollman } 65418316Swollman } 65518316Swollman } 65618316Swollman 65718316Swollman if (rip->rip_vers == RIPv1 65818316Swollman || 0 == (mask = ntohl(n->n_mask))) { 65918316Swollman mask = ripv1_mask_host(dst,aifp); 66018316Swollman } else if ((ntohl(dst) & ~mask) != 0) { 66119880Swollman msglim(&bad_mask, FROM_NADDR, 66219880Swollman "router %s sent bad netmask" 66346303Smarkm " %#lx with %s", 66419880Swollman naddr_ntoa(FROM_NADDR), 66546303Smarkm (u_long)mask, 66619880Swollman naddr_ntoa(dst)); 66718316Swollman continue; 66818316Swollman } 66918316Swollman if (rip->rip_vers == RIPv1) 67018316Swollman n->n_tag = 0; 67118316Swollman 67218316Swollman /* Adjust metric according to incoming interface.. 67318316Swollman */ 674126250Sbms n->n_metric += (aifp->int_metric 675126250Sbms + aifp->int_adj_inmetric); 67618316Swollman if (n->n_metric > HOPCNT_INFINITY) 67718316Swollman n->n_metric = HOPCNT_INFINITY; 67818316Swollman 67946303Smarkm /* Should we trust this route from this router? */ 68046303Smarkm if (tg && (tn = tg->tgate_nets)->mask != 0) { 68146303Smarkm for (i = 0; i < MAX_TGATE_NETS; i++, tn++) { 68246303Smarkm if (on_net(dst, tn->net, tn->mask) 68346303Smarkm && tn->mask <= mask) 68446303Smarkm break; 68546303Smarkm } 68646303Smarkm if (i >= MAX_TGATE_NETS || tn->mask == 0) { 68746303Smarkm trace_pkt(" ignored unauthorized %s", 68846303Smarkm addrname(dst,mask,0)); 68946303Smarkm continue; 69046303Smarkm } 69146303Smarkm } 69246303Smarkm 69318316Swollman /* Recognize and ignore a default route we faked 69418316Swollman * which is being sent back to us by a machine with 69518316Swollman * broken split-horizon. 69618316Swollman * Be a little more paranoid than that, and reject 69718316Swollman * default routes with the same metric we advertised. 69818316Swollman */ 69918316Swollman if (aifp->int_d_metric != 0 70018316Swollman && dst == RIP_DEFAULT 70146303Smarkm && (int)n->n_metric >= aifp->int_d_metric) 70218316Swollman continue; 70318316Swollman 70418316Swollman /* We can receive aggregated RIPv2 routes that must 70518316Swollman * be broken down before they are transmitted by 70618316Swollman * RIPv1 via an interface on a subnet. 70718316Swollman * We might also receive the same routes aggregated 70818316Swollman * via other RIPv2 interfaces. 70918316Swollman * This could cause duplicate routes to be sent on 71018316Swollman * the RIPv1 interfaces. "Longest matching variable 71118316Swollman * length netmasks" lets RIPv2 listeners understand, 71218316Swollman * but breaking down the aggregated routes for RIPv1 71318316Swollman * listeners can produce duplicate routes. 71418316Swollman * 71518316Swollman * Breaking down aggregated routes here bloats 71618316Swollman * the daemon table, but does not hurt the kernel 71718316Swollman * table, since routes are always aggregated for 71818316Swollman * the kernel. 71918316Swollman * 72018316Swollman * Notice that this does not break down network 72118316Swollman * routes corresponding to subnets. This is part 72218316Swollman * of the defense against RS_NET_SYN. 72318316Swollman */ 72418316Swollman if (have_ripv1_out 72518316Swollman && (((rt = rtget(dst,mask)) == 0 72619880Swollman || !(rt->rt_state & RS_NET_SYN))) 72719880Swollman && (v1_mask = ripv1_mask_net(dst,0)) > mask) { 72818316Swollman ddst_h = v1_mask & -v1_mask; 72918316Swollman i = (v1_mask & ~mask)/ddst_h; 73018316Swollman if (i >= 511) { 73118316Swollman /* Punt if we would have to generate 73218316Swollman * an unreasonable number of routes. 73318316Swollman */ 73446303Smarkm if (TRACECONTENTS) 73546303Smarkm trace_misc("accept %s-->%s as 1" 73646303Smarkm " instead of %d routes", 73746303Smarkm addrname(dst,mask,0), 73846303Smarkm naddr_ntoa(FROM_NADDR), 73946303Smarkm i+1); 74018316Swollman i = 0; 74118316Swollman } else { 74218316Swollman mask = v1_mask; 74318316Swollman } 74418316Swollman } else { 74518316Swollman i = 0; 74618316Swollman } 74718316Swollman 74846303Smarkm new.rts_gate = gate; 74946303Smarkm new.rts_router = FROM_NADDR; 75046303Smarkm new.rts_metric = n->n_metric; 75146303Smarkm new.rts_tag = n->n_tag; 75246303Smarkm new.rts_time = now.tv_sec; 75346303Smarkm new.rts_ifp = aifp; 75446303Smarkm new.rts_de_ag = i; 75546303Smarkm j = 0; 75618316Swollman for (;;) { 75746303Smarkm input_route(dst, mask, &new, n); 75846303Smarkm if (++j > i) 75918316Swollman break; 76018316Swollman dst = htonl(ntohl(dst) + ddst_h); 76118316Swollman } 76219880Swollman } while (++n < lim); 76318316Swollman break; 76418316Swollman } 76519880Swollman#undef FROM_NADDR 76618316Swollman} 76718316Swollman 76818316Swollman 76918316Swollman/* Process a single input route. 77018316Swollman */ 77118316Swollmanstatic void 77246303Smarkminput_route(naddr dst, /* network order */ 77318316Swollman naddr mask, 77446303Smarkm struct rt_spare *new, 77518316Swollman struct netinfo *n) 77618316Swollman{ 77718316Swollman int i; 77818316Swollman struct rt_entry *rt; 77918316Swollman struct rt_spare *rts, *rts0; 78018316Swollman struct interface *ifp1; 78118316Swollman 78218316Swollman 78318316Swollman /* See if the other guy is telling us to send our packets to him. 78418316Swollman * Sometimes network routes arrive over a point-to-point link for 78518316Swollman * the network containing the address(es) of the link. 78618316Swollman * 78718316Swollman * If our interface is broken, switch to using the other guy. 78818316Swollman */ 78918316Swollman ifp1 = ifwithaddr(dst, 1, 1); 79018316Swollman if (ifp1 != 0 79119880Swollman && (!(ifp1->int_state & IS_BROKE) 79219880Swollman || (ifp1->int_state & IS_PASSIVE))) 79318316Swollman return; 79418316Swollman 79518316Swollman /* Look for the route in our table. 79618316Swollman */ 79718316Swollman rt = rtget(dst, mask); 79818316Swollman 79918316Swollman /* Consider adding the route if we do not already have it. 80018316Swollman */ 80118316Swollman if (rt == 0) { 80218316Swollman /* Ignore unknown routes being poisoned. 80318316Swollman */ 80446303Smarkm if (new->rts_metric == HOPCNT_INFINITY) 80518316Swollman return; 80618316Swollman 80718316Swollman /* Ignore the route if it points to us */ 80818316Swollman if (n->n_nhop != 0 80918316Swollman && 0 != ifwithaddr(n->n_nhop, 1, 0)) 81018316Swollman return; 81118316Swollman 81218316Swollman /* If something has not gone crazy and tried to fill 81318316Swollman * our memory, accept the new route. 81418316Swollman */ 81518316Swollman if (total_routes < MAX_ROUTES) 81646303Smarkm rtadd(dst, mask, 0, new); 81718316Swollman return; 81818316Swollman } 81918316Swollman 82018316Swollman /* We already know about the route. Consider this update. 82118316Swollman * 82218316Swollman * If (rt->rt_state & RS_NET_SYN), then this route 82318316Swollman * is the same as a network route we have inferred 82418316Swollman * for subnets we know, in order to tell RIPv1 routers 82518316Swollman * about the subnets. 82618316Swollman * 82718316Swollman * It is impossible to tell if the route is coming 82818316Swollman * from a distant RIPv2 router with the standard 82918316Swollman * netmask because that router knows about the entire 83018316Swollman * network, or if it is a round-about echo of a 83118316Swollman * synthetic, RIPv1 network route of our own. 83218316Swollman * The worst is that both kinds of routes might be 83318316Swollman * received, and the bad one might have the smaller 83418316Swollman * metric. Partly solve this problem by never 83518316Swollman * aggregating into such a route. Also keep it 83618316Swollman * around as long as the interface exists. 83718316Swollman */ 83818316Swollman 83918316Swollman rts0 = rt->rt_spares; 84018316Swollman for (rts = rts0, i = NUM_SPARES; i != 0; i--, rts++) { 84146303Smarkm if (rts->rts_router == new->rts_router) 84218316Swollman break; 84318316Swollman /* Note the worst slot to reuse, 84418316Swollman * other than the current slot. 84518316Swollman */ 84618316Swollman if (rts0 == rt->rt_spares 84718316Swollman || BETTER_LINK(rt, rts0, rts)) 84818316Swollman rts0 = rts; 84918316Swollman } 85018316Swollman if (i != 0) { 85146303Smarkm /* Found a route from the router already in the table. 85218316Swollman */ 85318316Swollman 85446303Smarkm /* If the new route is a route broken down from an 85546303Smarkm * aggregated route, and if the previous route is either 85646303Smarkm * not a broken down route or was broken down from a finer 85746303Smarkm * netmask, and if the previous route is current, 85846303Smarkm * then forget this one. 85946303Smarkm */ 86046303Smarkm if (new->rts_de_ag > rts->rts_de_ag 86146303Smarkm && now_stale <= rts->rts_time) 86246303Smarkm return; 86346303Smarkm 86418316Swollman /* Keep poisoned routes around only long enough to pass 86546303Smarkm * the poison on. Use a new timestamp for good routes. 86618316Swollman */ 86746303Smarkm if (rts->rts_metric == HOPCNT_INFINITY 86846303Smarkm && new->rts_metric == HOPCNT_INFINITY) 86946303Smarkm new->rts_time = rts->rts_time; 87018316Swollman 87118316Swollman /* If this is an update for the router we currently prefer, 87218316Swollman * then note it. 87318316Swollman */ 87418316Swollman if (i == NUM_SPARES) { 87546303Smarkm rtchange(rt, rt->rt_state, new, 0); 87618316Swollman /* If the route got worse, check for something better. 87718316Swollman */ 87846303Smarkm if (new->rts_metric > rts->rts_metric) 87918316Swollman rtswitch(rt, 0); 88018316Swollman return; 88118316Swollman } 88218316Swollman 88318316Swollman /* This is an update for a spare route. 88418316Swollman * Finished if the route is unchanged. 88518316Swollman */ 88646303Smarkm if (rts->rts_gate == new->rts_gate 88746303Smarkm && rts->rts_metric == new->rts_metric 88846303Smarkm && rts->rts_tag == new->rts_tag) { 88946303Smarkm trace_upslot(rt, rts, new); 89046303Smarkm *rts = *new; 89118316Swollman return; 89218316Swollman } 89346303Smarkm /* Forget it if it has gone bad. 89446303Smarkm */ 89546303Smarkm if (new->rts_metric == HOPCNT_INFINITY) { 89646303Smarkm rts_delete(rt, rts); 89746303Smarkm return; 89846303Smarkm } 89918316Swollman 90018316Swollman } else { 90118316Swollman /* The update is for a route we know about, 90218316Swollman * but not from a familiar router. 90318316Swollman * 90418316Swollman * Ignore the route if it points to us. 90518316Swollman */ 90618316Swollman if (n->n_nhop != 0 90718316Swollman && 0 != ifwithaddr(n->n_nhop, 1, 0)) 90818316Swollman return; 90918316Swollman 91046303Smarkm /* the loop above set rts0=worst spare */ 91118316Swollman rts = rts0; 91218316Swollman 91318316Swollman /* Save the route as a spare only if it has 91418316Swollman * a better metric than our worst spare. 91518316Swollman * This also ignores poisoned routes (those 91618316Swollman * received with metric HOPCNT_INFINITY). 91718316Swollman */ 91846303Smarkm if (new->rts_metric >= rts->rts_metric) 91918316Swollman return; 92018316Swollman } 92118316Swollman 92246303Smarkm trace_upslot(rt, rts, new); 92346303Smarkm *rts = *new; 92418316Swollman 92518316Swollman /* try to switch to a better route */ 92618316Swollman rtswitch(rt, rts); 92718316Swollman} 92819880Swollman 92919880Swollman 93019880Swollmanstatic int /* 0 if bad */ 93119880Swollmanck_passwd(struct interface *aifp, 93219880Swollman struct rip *rip, 93319880Swollman void *lim, 93419880Swollman naddr from, 93519880Swollman struct msg_limit *use_authp) 93619880Swollman{ 93719880Swollman# define NA (rip->rip_auths) 93819880Swollman struct netauth *na2; 93920339Swollman struct auth *ap; 94019880Swollman MD5_CTX md5_ctx; 94119880Swollman u_char hash[RIP_AUTH_PW_LEN]; 94246303Smarkm int i, len; 94319880Swollman 944190718Sphk assert(aifp != NULL); 94519880Swollman if ((void *)NA >= lim || NA->a_family != RIP_AF_AUTH) { 94619880Swollman msglim(use_authp, from, "missing password from %s", 94719880Swollman naddr_ntoa(from)); 94819880Swollman return 0; 94919880Swollman } 95019880Swollman 95120339Swollman /* accept any current (+/- 24 hours) password 95220339Swollman */ 95320339Swollman for (ap = aifp->int_auth, i = 0; i < MAX_AUTH_KEYS; i++, ap++) { 95420339Swollman if (ap->type != NA->a_type 95520339Swollman || (u_long)ap->start > (u_long)clk.tv_sec+DAY 95620339Swollman || (u_long)ap->end+DAY < (u_long)clk.tv_sec) 95720339Swollman continue; 95819880Swollman 95920339Swollman if (NA->a_type == RIP_AUTH_PW) { 96046303Smarkm if (!memcmp(NA->au.au_pw, ap->key, RIP_AUTH_PW_LEN)) 96119880Swollman return 1; 96219880Swollman 96320339Swollman } else { 96420339Swollman /* accept MD5 secret with the right key ID 96520339Swollman */ 96620339Swollman if (NA->au.a_md5.md5_keyid != ap->keyid) 96720339Swollman continue; 96819880Swollman 96946303Smarkm len = ntohs(NA->au.a_md5.md5_pkt_len); 97046303Smarkm if ((len-sizeof(*rip)) % sizeof(*NA) != 0 97146303Smarkm || len != (char *)lim-(char*)rip-(int)sizeof(*NA)) { 97219880Swollman msglim(use_authp, from, 97346303Smarkm "wrong MD5 RIPv2 packet length of %d" 97446303Smarkm " instead of %d from %s", 97546303Smarkm len, (int)((char *)lim-(char *)rip 97646303Smarkm -sizeof(*NA)), 97719880Swollman naddr_ntoa(from)); 97819880Swollman return 0; 97919880Swollman } 98046303Smarkm na2 = (struct netauth *)((char *)rip+len); 98146303Smarkm 98246303Smarkm /* Given a good hash value, these are not security 98346303Smarkm * problems so be generous and accept the routes, 98446303Smarkm * after complaining. 98546303Smarkm */ 98646303Smarkm if (TRACEPACKETS) { 98746303Smarkm if (NA->au.a_md5.md5_auth_len 988126250Sbms != RIP_AUTH_MD5_HASH_LEN) 98946303Smarkm msglim(use_authp, from, 99046303Smarkm "unknown MD5 RIPv2 auth len %#x" 99146303Smarkm " instead of %#x from %s", 99246303Smarkm NA->au.a_md5.md5_auth_len, 993190745Sphk (unsigned)RIP_AUTH_MD5_HASH_LEN, 99446303Smarkm naddr_ntoa(from)); 99546303Smarkm if (na2->a_family != RIP_AF_AUTH) 99646303Smarkm msglim(use_authp, from, 99746303Smarkm "unknown MD5 RIPv2 family %#x" 99846303Smarkm " instead of %#x from %s", 99946303Smarkm na2->a_family, RIP_AF_AUTH, 100046303Smarkm naddr_ntoa(from)); 100146303Smarkm if (na2->a_type != ntohs(1)) 100246303Smarkm msglim(use_authp, from, 100346303Smarkm "MD5 RIPv2 hash has %#x" 100446303Smarkm " instead of %#x from %s", 100546303Smarkm na2->a_type, ntohs(1), 100646303Smarkm naddr_ntoa(from)); 100746303Smarkm } 100846303Smarkm 100919880Swollman MD5Init(&md5_ctx); 1010126250Sbms MD5Update(&md5_ctx, (u_char *)rip, 1011126250Sbms len + RIP_AUTH_MD5_HASH_XTRA); 1012126250Sbms MD5Update(&md5_ctx, ap->key, RIP_AUTH_MD5_KEY_LEN); 101319880Swollman MD5Final(hash, &md5_ctx); 101446303Smarkm if (!memcmp(hash, na2->au.au_pw, sizeof(hash))) 101546303Smarkm return 1; 101619880Swollman } 101719880Swollman } 101819880Swollman 101919880Swollman msglim(use_authp, from, "bad password from %s", 102019880Swollman naddr_ntoa(from)); 102119880Swollman return 0; 102219880Swollman#undef NA 102319880Swollman} 1024