872b698bd4
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1038 lines
28 KiB
C
1038 lines
28 KiB
C
/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (c) 1983, 1988, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include "defs.h"
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#ifdef __NetBSD__
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__RCSID("$NetBSD$");
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#elif defined(__FreeBSD__)
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__RCSID("$FreeBSD$");
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#else
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__RCSID("$Revision: 2.26 $");
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#ident "$Revision: 2.26 $"
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#endif
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static void input(struct sockaddr_in *, struct interface *, struct interface *,
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struct rip *, int);
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static void input_route(naddr, naddr, struct rt_spare *, struct netinfo *);
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static int ck_passwd(struct interface *, struct rip *, void *,
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naddr, struct msg_limit *);
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/* process RIP input
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*/
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void
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read_rip(int sock,
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struct interface *sifp)
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{
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struct sockaddr_in from;
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struct interface *aifp;
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socklen_t fromlen;
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int cc;
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#ifdef USE_PASSIFNAME
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static struct msg_limit bad_name;
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struct {
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char ifname[IFNAMSIZ];
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union pkt_buf pbuf;
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} inbuf;
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#else
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struct {
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union pkt_buf pbuf;
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} inbuf;
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#endif
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for (;;) {
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fromlen = sizeof(from);
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cc = recvfrom(sock, &inbuf, sizeof(inbuf), 0,
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(struct sockaddr*)&from, &fromlen);
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if (cc <= 0) {
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if (cc < 0 && errno != EWOULDBLOCK)
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LOGERR("recvfrom(rip)");
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break;
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}
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if (fromlen != sizeof(struct sockaddr_in))
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logbad(1,"impossible recvfrom(rip) fromlen=%d",
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(int)fromlen);
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/* aifp is the "authenticated" interface via which the packet
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* arrived. In fact, it is only the interface on which
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* the packet should have arrived based on is source
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* address.
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* sifp is interface associated with the socket through which
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* the packet was received.
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*/
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#ifdef USE_PASSIFNAME
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if ((cc -= sizeof(inbuf.ifname)) < 0)
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logbad(0,"missing USE_PASSIFNAME; only %d bytes",
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cc+sizeof(inbuf.ifname));
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/* check the remote interfaces first */
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LIST_FOREACH(aifp, &remote_if, remote_list) {
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if (aifp->int_addr == from.sin_addr.s_addr)
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break;
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}
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if (aifp == NULL) {
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aifp = ifwithname(inbuf.ifname, 0);
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if (aifp == NULL) {
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msglim(&bad_name, from.sin_addr.s_addr,
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"impossible interface name %.*s",
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IFNAMSIZ, inbuf.ifname);
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} else if (((aifp->int_if_flags & IFF_POINTOPOINT)
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&& aifp->int_dstaddr!=from.sin_addr.s_addr)
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|| (!(aifp->int_if_flags & IFF_POINTOPOINT)
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&& !on_net(from.sin_addr.s_addr,
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aifp->int_net,
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aifp->int_mask))) {
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/* If it came via the wrong interface, do not
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* trust it.
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*/
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aifp = NULL;
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}
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}
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#else
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aifp = iflookup(from.sin_addr.s_addr);
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#endif
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if (sifp == NULL)
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sifp = aifp;
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input(&from, sifp, aifp, &inbuf.pbuf.rip, cc);
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}
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}
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/* Process a RIP packet
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*/
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static void
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input(struct sockaddr_in *from, /* received from this IP address */
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struct interface *sifp, /* interface of incoming socket */
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struct interface *aifp, /* "authenticated" interface */
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struct rip *rip,
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int cc)
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{
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# define FROM_NADDR from->sin_addr.s_addr
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static struct msg_limit use_auth, bad_len, bad_mask;
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static struct msg_limit unk_router, bad_router, bad_nhop;
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struct rt_entry *rt;
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struct rt_spare new;
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struct netinfo *n, *lim;
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struct interface *ifp1;
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naddr gate, mask, v1_mask, dst, ddst_h = 0;
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struct auth *ap;
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struct tgate *tg = NULL;
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struct tgate_net *tn;
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int i, j;
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/* Notice when we hear from a remote gateway
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*/
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if (aifp != NULL
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&& (aifp->int_state & IS_REMOTE))
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aifp->int_act_time = now.tv_sec;
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trace_rip("Recv", "from", from, sifp, rip, cc);
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if (sifp == NULL) {
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trace_pkt(" discard a request from an indirect router"
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" (possibly an attack)");
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return;
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}
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if (rip->rip_vers == 0) {
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msglim(&bad_router, FROM_NADDR,
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"RIP version 0, cmd %d, packet received from %s",
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rip->rip_cmd, naddr_ntoa(FROM_NADDR));
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return;
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} else if (rip->rip_vers > RIPv2) {
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rip->rip_vers = RIPv2;
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}
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if (cc > (int)OVER_MAXPACKETSIZE) {
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msglim(&bad_router, FROM_NADDR,
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"packet at least %d bytes too long received from %s",
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cc-MAXPACKETSIZE, naddr_ntoa(FROM_NADDR));
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return;
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}
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n = rip->rip_nets;
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lim = (struct netinfo *)((char*)rip + cc);
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/* Notice authentication.
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* As required by section 4.2 in RFC 1723, discard authenticated
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* RIPv2 messages, but only if configured for that silliness.
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*
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* RIPv2 authentication is lame. Why authenticate queries?
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* Why should a RIPv2 implementation with authentication disabled
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* not be able to listen to RIPv2 packets with authentication, while
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* RIPv1 systems will listen? Crazy!
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*/
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if (!auth_ok
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&& rip->rip_vers == RIPv2
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&& n < lim && n->n_family == RIP_AF_AUTH) {
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msglim(&use_auth, FROM_NADDR,
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"RIPv2 message with authentication from %s discarded",
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naddr_ntoa(FROM_NADDR));
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return;
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}
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switch (rip->rip_cmd) {
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case RIPCMD_REQUEST:
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/* For mere requests, be a little sloppy about the source
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*/
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if (aifp == NULL)
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aifp = sifp;
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/* Are we talking to ourself or a remote gateway?
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*/
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ifp1 = ifwithaddr(FROM_NADDR, 0, 1);
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if (ifp1) {
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if (ifp1->int_state & IS_REMOTE) {
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/* remote gateway */
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aifp = ifp1;
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if (check_remote(aifp)) {
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aifp->int_act_time = now.tv_sec;
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(void)if_ok(aifp, "remote ");
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}
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} else if (from->sin_port == htons(RIP_PORT)) {
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trace_pkt(" discard our own RIP request");
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return;
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}
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}
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/* did the request come from a router?
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*/
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if (from->sin_port == htons(RIP_PORT)) {
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/* yes, ignore the request if RIP is off so that
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* the router does not depend on us.
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*/
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if (rip_sock < 0
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|| (aifp != NULL
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&& IS_RIP_OUT_OFF(aifp->int_state))) {
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trace_pkt(" discard request while RIP off");
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return;
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}
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}
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/* According to RFC 1723, we should ignore unauthenticated
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* queries. That is too silly to bother with. Sheesh!
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* Are forwarding tables supposed to be secret, when
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* a bad guy can infer them with test traffic? When RIP
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* is still the most common router-discovery protocol
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* and so hosts need to send queries that will be answered?
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* What about `rtquery`?
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* Maybe on firewalls you'd care, but not enough to
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* give up the diagnostic facilities of remote probing.
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*/
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if (n >= lim) {
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msglim(&bad_len, FROM_NADDR, "empty request from %s",
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naddr_ntoa(FROM_NADDR));
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return;
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}
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if (cc%sizeof(*n) != sizeof(struct rip)%sizeof(*n)) {
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msglim(&bad_len, FROM_NADDR,
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"request of bad length (%d) from %s",
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cc, naddr_ntoa(FROM_NADDR));
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}
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if (rip->rip_vers == RIPv2
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&& (aifp == NULL || (aifp->int_state & IS_NO_RIPV1_OUT))) {
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v12buf.buf->rip_vers = RIPv2;
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/* If we have a secret but it is a cleartext secret,
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* do not disclose our secret unless the other guy
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* already knows it.
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*/
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ap = find_auth(aifp);
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if (ap != NULL && ap->type == RIP_AUTH_PW
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&& n->n_family == RIP_AF_AUTH
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&& !ck_passwd(aifp,rip,lim,FROM_NADDR,&use_auth))
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ap = NULL;
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} else {
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v12buf.buf->rip_vers = RIPv1;
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ap = NULL;
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}
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clr_ws_buf(&v12buf, ap);
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do {
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n->n_metric = ntohl(n->n_metric);
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/* A single entry with family RIP_AF_UNSPEC and
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* metric HOPCNT_INFINITY means "all routes".
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* We respond to routers only if we are acting
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* as a supplier, or to anyone other than a router
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* (i.e. a query).
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*/
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if (n->n_family == RIP_AF_UNSPEC
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&& n->n_metric == HOPCNT_INFINITY) {
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/* Answer a query from a utility program
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* with all we know.
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*/
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if (aifp == NULL) {
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trace_pkt("ignore remote query");
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return;
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}
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if (from->sin_port != htons(RIP_PORT)) {
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/*
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* insecure: query from non-router node
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* > 1: allow from distant node
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* > 0: allow from neighbor node
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* == 0: deny
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*/
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if ((aifp != NULL && insecure > 0) ||
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(aifp == NULL && insecure > 1))
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supply(from, aifp, OUT_QUERY, 0,
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rip->rip_vers,
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ap != NULL);
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else
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trace_pkt("Warning: "
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"possible attack detected");
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return;
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}
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/* A router trying to prime its tables.
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* Filter the answer in the about same way
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* broadcasts are filtered.
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*
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* Only answer a router if we are a supplier
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* to keep an unwary host that is just starting
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* from picking us as a router.
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*/
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if (aifp == NULL) {
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trace_pkt("ignore distant router");
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return;
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}
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if (!supplier
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|| IS_RIP_OFF(aifp->int_state)) {
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trace_pkt("ignore; not supplying");
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return;
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}
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/* Do not answer a RIPv1 router if
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* we are sending RIPv2. But do offer
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* poor man's router discovery.
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*/
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if ((aifp->int_state & IS_NO_RIPV1_OUT)
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&& rip->rip_vers == RIPv1) {
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if (!(aifp->int_state & IS_PM_RDISC)) {
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trace_pkt("ignore; sending RIPv2");
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return;
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}
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v12buf.n->n_family = RIP_AF_INET;
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v12buf.n->n_dst = RIP_DEFAULT;
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i = aifp->int_d_metric;
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if (NULL != (rt = rtget(RIP_DEFAULT, 0))) {
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j = (rt->rt_metric
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+aifp->int_metric
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+aifp->int_adj_outmetric
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+1);
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if (i > j)
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i = j;
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}
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v12buf.n->n_metric = htonl(i);
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v12buf.n++;
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break;
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}
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/* Respond with RIPv1 instead of RIPv2 if
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* that is what we are broadcasting on the
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* interface to keep the remote router from
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* getting the wrong initial idea of the
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* routes we send.
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*/
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supply(from, aifp, OUT_UNICAST, 0,
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(aifp->int_state & IS_NO_RIPV1_OUT)
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? RIPv2 : RIPv1,
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ap != NULL);
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return;
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}
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/* Ignore authentication */
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if (n->n_family == RIP_AF_AUTH)
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continue;
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if (n->n_family != RIP_AF_INET) {
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msglim(&bad_router, FROM_NADDR,
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"request from %s for unsupported"
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" (af %d) %s",
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naddr_ntoa(FROM_NADDR),
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ntohs(n->n_family),
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naddr_ntoa(n->n_dst));
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return;
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}
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/* We are being asked about a specific destination.
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*/
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dst = n->n_dst;
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if (!check_dst(dst)) {
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msglim(&bad_router, FROM_NADDR,
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"bad queried destination %s from %s",
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naddr_ntoa(dst),
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naddr_ntoa(FROM_NADDR));
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return;
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}
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/* decide what mask was intended */
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if (rip->rip_vers == RIPv1
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|| 0 == (mask = ntohl(n->n_mask))
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|| 0 != (ntohl(dst) & ~mask))
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mask = ripv1_mask_host(dst, aifp);
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/* try to find the answer */
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rt = rtget(dst, mask);
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if (!rt && dst != RIP_DEFAULT)
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rt = rtfind(n->n_dst);
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if (v12buf.buf->rip_vers != RIPv1)
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v12buf.n->n_mask = mask;
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if (rt == NULL) {
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/* we do not have the answer */
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v12buf.n->n_metric = HOPCNT_INFINITY;
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} else {
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/* we have the answer, so compute the
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* right metric and next hop.
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*/
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v12buf.n->n_family = RIP_AF_INET;
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v12buf.n->n_dst = dst;
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j = rt->rt_metric+1;
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if (!aifp)
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++j;
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else
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j += (aifp->int_metric
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+ aifp->int_adj_outmetric);
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if (j < HOPCNT_INFINITY)
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v12buf.n->n_metric = j;
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else
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v12buf.n->n_metric = HOPCNT_INFINITY;
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if (v12buf.buf->rip_vers != RIPv1) {
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v12buf.n->n_tag = rt->rt_tag;
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v12buf.n->n_mask = mask;
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if (aifp != NULL
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&& on_net(rt->rt_gate,
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aifp->int_net,
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aifp->int_mask)
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&& rt->rt_gate != aifp->int_addr)
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v12buf.n->n_nhop = rt->rt_gate;
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}
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}
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v12buf.n->n_metric = htonl(v12buf.n->n_metric);
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/* Stop paying attention if we fill the output buffer.
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*/
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if (++v12buf.n >= v12buf.lim)
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break;
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} while (++n < lim);
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/* Send the answer about specific routes.
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*/
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if (ap != NULL && ap->type == RIP_AUTH_MD5)
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end_md5_auth(&v12buf, ap);
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if (from->sin_port != htons(RIP_PORT)) {
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/* query */
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(void)output(OUT_QUERY, from, aifp,
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v12buf.buf,
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((char *)v12buf.n - (char*)v12buf.buf));
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} else if (supplier) {
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(void)output(OUT_UNICAST, from, aifp,
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v12buf.buf,
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((char *)v12buf.n - (char*)v12buf.buf));
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} else {
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/* Only answer a router if we are a supplier
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* to keep an unwary host that is just starting
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* from picking us an a router.
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*/
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;
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}
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return;
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case RIPCMD_TRACEON:
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case RIPCMD_TRACEOFF:
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/* Notice that trace messages are turned off for all possible
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* abuse if _PATH_TRACE is undefined in pathnames.h.
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* Notice also that because of the way the trace file is
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* handled in trace.c, no abuse is plausible even if
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* _PATH_TRACE_ is defined.
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*
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* First verify message came from a privileged port. */
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if (ntohs(from->sin_port) > IPPORT_RESERVED) {
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msglog("trace command from untrusted port on %s",
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naddr_ntoa(FROM_NADDR));
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return;
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}
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if (aifp == NULL) {
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msglog("trace command from unknown router %s",
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naddr_ntoa(FROM_NADDR));
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return;
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}
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if (rip->rip_cmd == RIPCMD_TRACEON) {
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rip->rip_tracefile[cc-4] = '\0';
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|
set_tracefile((char*)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 (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));
|
|
}
|
|
|
|
/* verify message came from a router */
|
|
if (from->sin_port != ntohs(RIP_PORT)) {
|
|
msglim(&bad_router, FROM_NADDR,
|
|
" discard RIP response from unknown port"
|
|
" %d on %s",
|
|
ntohs(from->sin_port), naddr_ntoa(FROM_NADDR));
|
|
return;
|
|
}
|
|
|
|
if (rip_sock < 0) {
|
|
trace_pkt(" discard response while RIP off");
|
|
return;
|
|
}
|
|
|
|
/* Are we talking to ourself or a remote gateway?
|
|
*/
|
|
ifp1 = ifwithaddr(FROM_NADDR, 0, 1);
|
|
if (ifp1) {
|
|
if (ifp1->int_state & IS_REMOTE) {
|
|
/* remote gateway */
|
|
aifp = ifp1;
|
|
if (check_remote(aifp)) {
|
|
aifp->int_act_time = now.tv_sec;
|
|
(void)if_ok(aifp, "remote ");
|
|
}
|
|
} else {
|
|
trace_pkt(" discard our own RIP response");
|
|
return;
|
|
}
|
|
}
|
|
|
|
/* Accept routing packets from routers directly connected
|
|
* via broadcast or point-to-point networks, and from
|
|
* those listed in /etc/gateways.
|
|
*/
|
|
if (aifp == NULL) {
|
|
msglim(&unk_router, FROM_NADDR,
|
|
" discard response from %s"
|
|
" via unexpected interface",
|
|
naddr_ntoa(FROM_NADDR));
|
|
return;
|
|
}
|
|
if (IS_RIP_IN_OFF(aifp->int_state)) {
|
|
trace_pkt(" discard RIPv%d response"
|
|
" via disabled interface %s",
|
|
rip->rip_vers, aifp->int_name);
|
|
return;
|
|
}
|
|
|
|
if (n >= lim) {
|
|
msglim(&bad_len, FROM_NADDR, "empty response from %s",
|
|
naddr_ntoa(FROM_NADDR));
|
|
return;
|
|
}
|
|
|
|
if (((aifp->int_state & IS_NO_RIPV1_IN)
|
|
&& rip->rip_vers == RIPv1)
|
|
|| ((aifp->int_state & IS_NO_RIPV2_IN)
|
|
&& rip->rip_vers != RIPv1)) {
|
|
trace_pkt(" discard RIPv%d response",
|
|
rip->rip_vers);
|
|
return;
|
|
}
|
|
|
|
/* Ignore routes via dead interface.
|
|
*/
|
|
if (aifp->int_state & IS_BROKE) {
|
|
trace_pkt("discard response via broken interface %s",
|
|
aifp->int_name);
|
|
return;
|
|
}
|
|
|
|
/* If the interface cares, ignore bad routers.
|
|
* Trace but do not log this problem, because where it
|
|
* happens, it happens frequently.
|
|
*/
|
|
if (aifp->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 (aifp->int_auth[0].type != RIP_AUTH_NONE
|
|
&& rip->rip_vers != RIPv1
|
|
&& !ck_passwd(aifp,rip,lim,FROM_NADDR,&use_auth))
|
|
return;
|
|
|
|
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));
|
|
return;
|
|
}
|
|
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));
|
|
return;
|
|
}
|
|
|
|
/* 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,
|
|
aifp->int_net, aifp->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,aifp);
|
|
} else if ((ntohl(dst) & ~mask) != 0) {
|
|
msglim(&bad_mask, FROM_NADDR,
|
|
"router %s sent bad netmask"
|
|
" %#lx with %s",
|
|
naddr_ntoa(FROM_NADDR),
|
|
(u_long)mask,
|
|
naddr_ntoa(dst));
|
|
continue;
|
|
}
|
|
if (rip->rip_vers == RIPv1)
|
|
n->n_tag = 0;
|
|
|
|
/* Adjust metric according to incoming interface..
|
|
*/
|
|
n->n_metric += (aifp->int_metric
|
|
+ aifp->int_adj_inmetric);
|
|
if (n->n_metric > HOPCNT_INFINITY)
|
|
n->n_metric = HOPCNT_INFINITY;
|
|
|
|
/* Should we trust this route from this router? */
|
|
if (tg && (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 (aifp->int_d_metric != 0
|
|
&& dst == RIP_DEFAULT
|
|
&& (int)n->n_metric >= aifp->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) {
|
|
ddst_h = v1_mask & -v1_mask;
|
|
i = (v1_mask & ~mask)/ddst_h;
|
|
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 = aifp;
|
|
new.rts_de_ag = i;
|
|
j = 0;
|
|
for (;;) {
|
|
input_route(dst, mask, &new, n);
|
|
if (++j > i)
|
|
break;
|
|
dst = htonl(ntohl(dst) + ddst_h);
|
|
}
|
|
} while (++n < lim);
|
|
break;
|
|
}
|
|
#undef FROM_NADDR
|
|
}
|
|
|
|
|
|
/* Process a single input route.
|
|
*/
|
|
static void
|
|
input_route(naddr dst, /* network order */
|
|
naddr mask,
|
|
struct rt_spare *new,
|
|
struct netinfo *n)
|
|
{
|
|
int i;
|
|
struct rt_entry *rt;
|
|
struct rt_spare *rts, *rts0;
|
|
struct interface *ifp1;
|
|
|
|
|
|
/* See if the other guy is telling us to send our packets to him.
|
|
* Sometimes network routes arrive over a point-to-point link for
|
|
* the network containing the address(es) of the link.
|
|
*
|
|
* If our interface is broken, switch to using the other guy.
|
|
*/
|
|
ifp1 = ifwithaddr(dst, 1, 1);
|
|
if (ifp1 != NULL
|
|
&& (!(ifp1->int_state & IS_BROKE)
|
|
|| (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->n_nhop != 0
|
|
&& ifwithaddr(n->n_nhop, 1, 0) != NULL)
|
|
return;
|
|
|
|
/* If something has not gone crazy and tried to fill
|
|
* our memory, accept the new route.
|
|
*/
|
|
if (total_routes < MAX_ROUTES)
|
|
rtadd(dst, mask, 0, 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;
|
|
for (rts = rts0, i = 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 (rts0 == rt->rt_spares
|
|
|| 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 == NUM_SPARES) {
|
|
rtchange(rt, rt->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) {
|
|
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->n_nhop != 0
|
|
&& NULL != ifwithaddr(n->n_nhop, 1, 0))
|
|
return;
|
|
|
|
/* the loop above set rts0=worst spare */
|
|
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);
|
|
}
|
|
|
|
|
|
static int /* 0 if bad */
|
|
ck_passwd(struct interface *aifp,
|
|
struct rip *rip,
|
|
void *lim,
|
|
naddr from,
|
|
struct msg_limit *use_authp)
|
|
{
|
|
# define NA (rip->rip_auths)
|
|
struct netauth *na2;
|
|
struct auth *ap;
|
|
MD5_CTX md5_ctx;
|
|
u_char hash[RIP_AUTH_PW_LEN];
|
|
int i, len;
|
|
|
|
assert(aifp != NULL);
|
|
if ((void *)NA >= lim || NA->a_family != RIP_AF_AUTH) {
|
|
msglim(use_authp, from, "missing password from %s",
|
|
naddr_ntoa(from));
|
|
return 0;
|
|
}
|
|
|
|
/* 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
|
|
|| (u_long)ap->start > (u_long)clk.tv_sec+DAY
|
|
|| (u_long)ap->end+DAY < (u_long)clk.tv_sec)
|
|
continue;
|
|
|
|
if (NA->a_type == RIP_AUTH_PW) {
|
|
if (!memcmp(NA->au.au_pw, ap->key, RIP_AUTH_PW_LEN))
|
|
return 1;
|
|
|
|
} 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 != (char *)lim-(char*)rip-(int)sizeof(*NA)) {
|
|
msglim(use_authp, from,
|
|
"wrong MD5 RIPv2 packet length of %d"
|
|
" instead of %d from %s",
|
|
len, (int)((char *)lim-(char *)rip
|
|
-sizeof(*NA)),
|
|
naddr_ntoa(from));
|
|
return 0;
|
|
}
|
|
na2 = (struct netauth *)((char *)rip+len);
|
|
|
|
/* 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_HASH_LEN)
|
|
msglim(use_authp, from,
|
|
"unknown MD5 RIPv2 auth len %#x"
|
|
" instead of %#x from %s",
|
|
NA->au.a_md5.md5_auth_len,
|
|
(unsigned)RIP_AUTH_MD5_HASH_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 != ntohs(1))
|
|
msglim(use_authp, from,
|
|
"MD5 RIPv2 hash has %#x"
|
|
" instead of %#x from %s",
|
|
na2->a_type, ntohs(1),
|
|
naddr_ntoa(from));
|
|
}
|
|
|
|
MD5Init(&md5_ctx);
|
|
MD5Update(&md5_ctx, (u_char *)rip,
|
|
len + RIP_AUTH_MD5_HASH_XTRA);
|
|
MD5Update(&md5_ctx, ap->key, RIP_AUTH_MD5_KEY_LEN);
|
|
MD5Final(hash, &md5_ctx);
|
|
if (!memcmp(hash, na2->au.au_pw, sizeof(hash)))
|
|
return 1;
|
|
}
|
|
}
|
|
|
|
msglim(use_authp, from, "bad password from %s",
|
|
naddr_ntoa(from));
|
|
return 0;
|
|
#undef NA
|
|
}
|