1 /*
2 * Copyright (c) 1985, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This file includes significant work done at Cornell University by
6 * Bill Nesheim. That work included by permission.
7 *
8 * %sccs.include.redist.c%
9 */
10
11 #ifndef lint
12 static char sccsid[] = "@(#)input.c 8.1 (Berkeley) 06/05/93";
13 #endif /* not lint */
14
15 /*
16 * XNS Routing Table Management Daemon
17 */
18 #include "defs.h"
19
20 struct sockaddr *
xns_nettosa(net)21 xns_nettosa(net)
22 union ns_net net;
23 {
24 static struct sockaddr_ns sxn;
25 extern char ether_broadcast_addr[6];
26
27 bzero(&sxn, sizeof (struct sockaddr_ns));
28 sxn.sns_family = AF_NS;
29 sxn.sns_len = sizeof (sxn);
30 sxn.sns_addr.x_net = net;
31 sxn.sns_addr.x_host = *(union ns_host *)ether_broadcast_addr;
32 return( (struct sockaddr *)&sxn);
33
34 }
35
36 /*
37 * Process a newly received packet.
38 */
39 rip_input(from, size)
40 struct sockaddr *from;
41 int size;
42 {
43 struct rt_entry *rt;
44 struct netinfo *n;
45 struct interface *ifp;
46 int newsize;
47 struct afswitch *afp;
48
49
50 ifp = 0;
51 TRACE_INPUT(ifp, from, size);
52 if (from->sa_family >= AF_MAX)
53 return;
54 afp = &afswitch[from->sa_family];
55
56 size -= sizeof (u_short) /* command */;
57 n = msg->rip_nets;
58
59 switch (ntohs(msg->rip_cmd)) {
60
61 case RIPCMD_REQUEST:
62 newsize = 0;
63 while (size > 0) {
64 if (size < sizeof (struct netinfo))
65 break;
66 size -= sizeof (struct netinfo);
67
68 /*
69 * A single entry with rip_dst == DSTNETS_ALL and
70 * metric ``infinity'' means ``all routes''.
71 */
72 if (ns_neteqnn(n->rip_dst, ns_anynet) &&
73 ntohs(n->rip_metric) == HOPCNT_INFINITY &&
74 size == 0) {
75 ifp = if_ifwithnet(from);
76 supply(from, 0, ifp);
77 return;
78 }
79 /*
80 * request for specific nets
81 */
82 rt = rtlookup(xns_nettosa(n->rip_dst));
83 if (ftrace) {
84 fprintf(ftrace,
85 "specific request for %s",
86 xns_nettoa(n->rip_dst));
87 fprintf(ftrace,
88 " yields route %x\n",
89 rt);
90 }
91 n->rip_metric = htons( rt == 0 ? HOPCNT_INFINITY :
92 min(rt->rt_metric+1, HOPCNT_INFINITY));
93 n++;
94 newsize += sizeof (struct netinfo);
95 }
96 if (newsize > 0) {
97 msg->rip_cmd = htons(RIPCMD_RESPONSE);
98 newsize += sizeof (u_short);
99 /* should check for if with dstaddr(from) first */
100 (*afp->af_output)(0, from, newsize);
101 ifp = if_ifwithnet(from);
102 TRACE_OUTPUT(ifp, from, newsize);
103 if (ftrace) {
104 fprintf(ftrace,
105 "request arrived on interface %s\n",
106 ifp->int_name);
107 }
108 }
109 return;
110
111 case RIPCMD_RESPONSE:
112 /* verify message came from a router */
113 if ((*afp->af_portmatch)(from) == 0)
114 return;
115 (*afp->af_canon)(from);
116 /* are we talking to ourselves? */
117 if (ifp = if_ifwithaddr(from)) {
118 rt = rtfind(from);
119 if (rt == 0 || (rt->rt_state & RTS_INTERFACE) == 0)
120 addrouteforif(ifp);
121 else
122 rt->rt_timer = 0;
123 return;
124 }
125 /* Update timer for interface on which the packet arrived.
126 * If from other end of a point-to-point link that isn't
127 * in the routing tables, (re-)add the route.
128 */
129 if ((rt = rtfind(from)) && (rt->rt_state & RTS_INTERFACE)) {
130 if(ftrace) fprintf(ftrace, "Got route\n");
131 rt->rt_timer = 0;
132 } else if (ifp = if_ifwithdstaddr(from)) {
133 if(ftrace) fprintf(ftrace, "Got partner\n");
134 addrouteforif(ifp);
135 }
136 for (; size > 0; size -= sizeof (struct netinfo), n++) {
137 struct sockaddr *sa;
138 if (size < sizeof (struct netinfo))
139 break;
140 if ((unsigned) ntohs(n->rip_metric) >= HOPCNT_INFINITY)
141 continue;
142 rt = rtfind(sa = xns_nettosa(n->rip_dst));
143 if (rt == 0) {
144 rtadd(sa, from, ntohs(n->rip_metric), 0);
145 continue;
146 }
147
148 /*
149 * Update if from gateway and different,
150 * from anywhere and shorter, or getting stale and equivalent.
151 */
152 if ((equal(from, &rt->rt_router) &&
153 ntohs(n->rip_metric) != rt->rt_metric ) ||
154 (unsigned) ntohs(n->rip_metric) < rt->rt_metric ||
155 (rt->rt_timer > (EXPIRE_TIME/2) &&
156 rt->rt_metric == ntohs(n->rip_metric))) {
157 rtchange(rt, from, ntohs(n->rip_metric));
158 rt->rt_timer = 0;
159 }
160 }
161 return;
162 }
163 }
164