1 #ifndef lint 2 static char sccsid[] = "@(#)input.c 4.1 11/02/82"; 3 #endif 4 5 /* 6 * Routing Table Management Daemon 7 */ 8 #include "router.h" 9 10 /* 11 * Process a newly received packet. 12 */ 13 rip_input(from, size) 14 struct sockaddr *from; 15 int size; 16 { 17 struct rt_entry *rt; 18 struct netinfo *n; 19 struct interface *ifp; 20 int newsize; 21 struct afswitch *afp; 22 23 ifp = 0; 24 TRACE_INPUT(ifp, from, size); 25 if (from->sa_family >= AF_MAX) 26 return; 27 afp = &afswitch[from->sa_family]; 28 switch (msg->rip_cmd) { 29 30 case RIPCMD_REQUEST: 31 newsize = 0; 32 size -= 4 * sizeof (char); 33 n = msg->rip_nets; 34 while (size > 0) { 35 if (size < sizeof (struct netinfo)) 36 break; 37 size -= sizeof (struct netinfo); 38 39 /* 40 * A single entry with sa_family == AF_UNSPEC and 41 * metric ``infinity'' means ``all routes''. 42 */ 43 if (n->rip_dst.sa_family == AF_UNSPEC && 44 n->rip_metric == HOPCNT_INFINITY && size == 0) { 45 supply(from, 0, ifp); 46 return; 47 } 48 rt = rtlookup(&n->rip_dst); 49 n->rip_metric = rt == 0 ? HOPCNT_INFINITY : 50 min(rt->rt_metric+1, HOPCNT_INFINITY); 51 n++, newsize += sizeof (struct netinfo); 52 } 53 if (newsize > 0) { 54 msg->rip_cmd = RIPCMD_RESPONSE; 55 newsize += sizeof (int); 56 (*afp->af_output)(s, from, newsize); 57 } 58 return; 59 60 case RIPCMD_TRACEON: 61 case RIPCMD_TRACEOFF: 62 /* verify message came from a priviledged port */ 63 if ((*afp->af_portcheck)(from) == 0) 64 return; 65 packet[size] = '\0'; 66 if (msg->rip_cmd == RIPCMD_TRACEON) 67 traceon(msg->rip_tracefile); 68 else 69 traceoff(); 70 return; 71 72 case RIPCMD_RESPONSE: 73 /* verify message came from a router */ 74 if ((*afp->af_portmatch)(from) == 0) 75 return; 76 (*afp->af_canon)(from); 77 /* are we talking to ourselves? */ 78 ifp = if_ifwithaddr(from); 79 if (ifp) { 80 rt = rtfind(from); 81 if (rt == 0) 82 addrouteforif(ifp); 83 else 84 rt->rt_timer = 0; 85 return; 86 } 87 size -= 4 * sizeof (char); 88 n = msg->rip_nets; 89 for (; size > 0; size -= sizeof (struct netinfo), n++) { 90 if (size < sizeof (struct netinfo)) 91 break; 92 if (n->rip_metric >= HOPCNT_INFINITY) 93 continue; 94 rt = rtlookup(&n->rip_dst); 95 if (rt == 0) { 96 rtadd(&n->rip_dst, from, n->rip_metric, 0); 97 continue; 98 } 99 100 /* 101 * Update if from gateway, shorter, or getting 102 * stale and equivalent. 103 */ 104 if (equal(from, &rt->rt_router) || 105 n->rip_metric < rt->rt_metric || 106 (rt->rt_timer > (EXPIRE_TIME/2) && 107 rt->rt_metric == n->rip_metric)) { 108 rtchange(rt, from, n->rip_metric); 109 rt->rt_timer = 0; 110 } 111 } 112 return; 113 } 114 } 115