input.c

VXWORKS源代码

                    }
                return;
                }

            /*
             * Update timer for interface route on which the message arrived.
             * If none is found and the sender is the other end of a 
             * point-to-point link that isn't registered in the routing 
             * tables, add or restore that route.
             */

            if ((rt = rtfind(from)) &&
                (rt->rt_state & (RTS_INTERFACE | RTS_REMOTE)))
                {
                rt->rt_timer = 0;
                if (rt->inKernel) 
                    ripRouteAgeUpdate (rt); /* Update age for IP group MIB. */
                }
            else if ((ifp = ripIfWithDstAddr(from, NULL)) &&
                     (rt == 0 || rt->rt_metric >= ifp->int_metric))
                addrouteforif(ifp);

            /* 
             * NOTE: The preceding rtfind() routine will not detect a 
             * match for updates from a router on the same supernet with 
             * a different class-based network number than the local
             * interfaces. (For instance, it will not reset the route 
             * timer for 192.168.254.0/23 when an update is received 
             * from 192.168.255.x/23 if the local interface has the 
             * address 192.168.254.x/23. This omission has no effect 
             * because the timer for an interface route is never 
             * incremented. The return value of 0 will not cause an
             * incorrect call to addrouteforif() because the search in
             *  ripIfWithDstAddr will always fail in this situation.
             */

            /*
             * Reset the pointer to validate the interface from which the
             * message arrived. Updates are accepted from routers directly 
             * connected via broadcast or point-to-point networks.
             */

            ifp = pErrorIfp;    /* Results of ripIfLookup on source address. */
            if ( (ifp->int_flags &
                     (IFF_BROADCAST | IFF_POINTOPOINT | IFF_REMOTE)) == 0 ||
                ifp->int_flags & IFF_PASSIVE)
                {
                /* Error: source does not use a directly-connected network. */

                if (memcmp(from, &badfrom, sizeof(badfrom)) != 0)
                    {
                    if (routedDebug)
                        logMsg ("packet from unknown router, %s\n",
                             (int)(*afswitch[from->sa_family].af_format)(from),
                                0, 0, 0, 0, 0);
                    badfrom = *from;
                    }
                pErrorIfp->ifStat.rip2IfStatRcvBadPackets++;
                return;
                }

            /*
             * At this point, the source address and port number of the 
             * response have been checked. It is from another host on a 
             * directly connected network and was sent to the correct port. 
             * Begin processing the datagram by ignoring the initial data 
             * (command, version, and two unused bytes) and leading 
             * authentication header, if any.
             */

            size = size - ((char *)n - (char *)rip);

            /* Now start processing actual route entries. */

            for (; size > 0; size -= sizeof (struct netinfo), n++)
                {
                if (size < sizeof (struct netinfo))
                    break;

                n->rip_dst.sa_family =
                    ntohs(osa(n->rip_dst)->sa_family);
                n->rip_dst.sa_len = sizeof(n->rip_dst);
                n->rip_metric = ntohl(n->rip_metric);

                /* Ignore any entry with an unknown address family. */

                if (n->rip_dst.sa_family >= AF_MAX ||
                    (afp = &afswitch[n->rip_dst.sa_family])->af_hash ==
                    (int (*)())0)
                    {
                    if (routedDebug)
                        logMsg("route in unsupported address family %d from %s"
                               "(af %d)\n", n->rip_dst.sa_family, 
                               (int)(*afswitch[from->sa_family].af_format)
                               (from), from->sa_family, 0, 0, 0);
                    pErrorIfp->ifStat.rip2IfStatRcvBadRoutes++;
                    continue;
                    }

                 /* 
                  * Ignore an entry if the unused fields are not zero.
                  * (These fields are only unused in version 1 updates).
                  */

                if (rip->rip_vers == 1)
                    {
                    if ( ((RIP2PKT *)n)->tag != 0)
                        {
                        pErrorIfp->ifStat.rip2IfStatRcvBadRoutes++;
                        continue;
                        }

                    if ( ((RIP2PKT *)n)->subnet != 0)
                        {
                        pErrorIfp->ifStat.rip2IfStatRcvBadRoutes++;
                        continue;
                        }

                    if ( ((RIP2PKT *)n)->gateway != 0)
                        {
                        pErrorIfp->ifStat.rip2IfStatRcvBadRoutes++;
                        continue;
                        }
                    }

                /* 
                 * Ignore any entry with an inappropriate address.
                 * The receiving interface is used to detect broadcast
                 * addresses if no netmask is present in the route update.
                 */

                if ( ((*afp->af_checkhost)(&n->rip_dst, ifp)) == 0)
                    {
                    if (routedDebug)
                        logMsg ("bad host in route from %s (af %d)\n",
                             (int)(*afswitch[from->sa_family].af_format)(from),
                                from->sa_family, 0, 0, 0, 0);
                    pErrorIfp->ifStat.rip2IfStatRcvBadRoutes++;
                    continue;
                    }

                if ((n->rip_metric == 0) ||
                    ((unsigned) n->rip_metric > HOPCNT_INFINITY))
                    {
                    if (memcmp(from, &badfrom2,
                               sizeof(badfrom2)) != 0)
                        {
                        if (routedDebug)
                            logMsg ("bad metric (%d) from %s\n", n->rip_metric,
                             (int)(*afswitch[from->sa_family].af_format)(from),
                                    0, 0, 0, 0);
                        badfrom2 = *from;
                        }
                    pErrorIfp->ifStat.rip2IfStatRcvBadRoutes++;
                    continue;
                    }

                rt = rtlookup (&n->rip_dst);

                /* 
                 * Do not allow a route learnt from other protocols to be
                 * replaced
                 */

                if (rt && ((rt->rt_state & RTS_OTHER) != 0))
                    continue;
                
                if (rt == 0 ||
                    (rt->rt_state & (RTS_INTERNAL|RTS_INTERFACE)) ==
                    (RTS_INTERNAL|RTS_INTERFACE))
                    {
                    /*
                     * If we're hearing a logical network route
                     * back from a peer to which we sent it,
                     * ignore it.
                     */
                    if (rt && rt->rt_state & RTS_SUBNET &&
                        (*afp->af_sendroute)(rt, from, ifp))
                        {
                        pErrorIfp->ifStat.rip2IfStatRcvBadRoutes++;
                        continue;
                        }

                    /*
                     * Adjust metric according to incoming interface.
                     */
                    if ((unsigned)n->rip_metric < HOPCNT_INFINITY)
                        {
                        /*
                         * Look for an equivalent route that
                         * includes this one before adding
                         * this route.
                         */

                        rt = rtfind(&n->rip_dst);
                        if ((rt && equal(from, &rt->rt_router)) &&
                            (rt->rt_metric <= n->rip_metric))
                            continue;

                        n->rip_metric += ifp->int_metric;

                        if (rip->rip_vers < 2)
                            {
                            rtadd (&n->rip_dst, from, n->rip_metric, 
                                   0, NULL, M2_ipRouteProto_rip, 0,
                                   ((struct sockaddr_in *)from)->
                                    sin_addr.s_addr, pErrorIfp);
                            }
                        else
                            {
                            ripSplitPacket (ifp, (struct sockaddr_in *)from, 
                                            &n->rip_dst, &gateway, &netmask,
                                            &tag);
                            if (((struct sockaddr_in *)&netmask)->
                                sin_addr.s_addr == -1)
                                {
                                pErrorIfp->ifStat.rip2IfStatRcvBadRoutes++;
                                continue;
                                }

                            /*
                             * RFC 1723, Section 3.4: check to see that the 
                             * gateway is directly reachable. If not, treat 
                             * that value as 0.0.0.0 by using the originator 
                             * as the gateway.
                             */

                            if ((((struct sockaddr_in *)&gateway)->
                                 sin_addr.s_addr & 
                                 htonl (ifp->int_subnetmask)) != 
                                (((struct sockaddr_in *)&ifp->int_addr)->
                                 sin_addr.s_addr & 
                                 htonl (ifp->int_subnetmask)))
                                {
                                ((struct sockaddr_in *)&gateway)->
                                    sin_addr.s_addr = 
                                    ((struct sockaddr_in *)from)->
                                    sin_addr.s_addr;
                                }

                            rtadd(&n->rip_dst, &gateway, n->rip_metric, 0,
                                  &netmask, M2_ipRouteProto_rip, tag,
                                  ((struct sockaddr_in *)from)->
                                  sin_addr.s_addr, pErrorIfp);
                            }
                        changes++;
                        }

                    continue;
                    }
                /*
                 * Update if from gateway and different,
                 * shorter, or equivalent but old route
                 * is getting stale.
                 */

                /*
                 * If this was a pre-existinng route then we can
                 * update it to be "infinite" and should.
                 * ANVL 7.13.
                 */

                origMetric = n->rip_metric;
                if ((unsigned) n->rip_metric < HOPCNT_INFINITY)
                    n->rip_metric += ifp->int_metric;

                if (n->rip_metric > HOPCNT_INFINITY)
                    {
                    pErrorIfp->ifStat.rip2IfStatRcvBadRoutes++;
                    continue;
                    }

                if (rip->rip_vers > 1)
                    {
                    ripSplitPacket(ifp, (struct sockaddr_in *)from, 
                                   &n->rip_dst, &gateway, &netmask,
                                   &tag);
                    if (((struct sockaddr_in *)&netmask)->
                        sin_addr.s_addr == -1)
                        {
                        pErrorIfp->ifStat.rip2IfStatRcvBadRoutes++;
                        continue;
                        }

                    /*
                     * RFC 1723, Section 3.4: check to see that the 
                     * gateway is directly reachable. If not, treat 
                     * that value as 0.0.0.0 by using the originator 
                     * as the gateway.
                     */
                    if ((((struct sockaddr_in *)&gateway)->sin_addr.s_addr & 
                         htonl (ifp->int_subnetmask)) != 
                        (((struct sockaddr_in *)&ifp->int_addr)->
                         sin_addr.s_addr & htonl (ifp->int_subnetmask)))
                        {
                        ((struct sockaddr_in *)&gateway)->sin_addr.s_addr = 
                            ((struct sockaddr_in *)from)->sin_addr.s_addr;
                        }
                    }

                /*
                 * We are making an assumption here that the address
                 * is an internet address (4 bytes long). Since we currently
                 * support only the AF_INET family its OK, but if that
                 * changes, the following check will need to be changed
                 * accordingly
                 */

                if (((struct sockaddr_in *)from)->sin_addr.s_addr ==
                    rt->rt_orgrouter)