mirror/freebsd
1
0
Fork 0
mirror of https://git.FreeBSD.org/src.git synced 2024-12-14 10:09:48 +00:00
Code Issues Releases Activity
05aa6e583b
freebsd/sbin/routed/input.c
Pedro F. Giffuni 8a16b7a18f General further adoption of SPDX licensing ID tags. 
Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
2017-11-20 19:49:47 +00:00

1038 lines
28 KiB
C
Raw Blame History

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