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1.1 root 1: /* route.c 6.2 83/10/20 */
2:
3: #include "../h/param.h"
4: #include "../h/systm.h"
5: #include "../h/mbuf.h"
6: #include "../h/protosw.h"
7: #include "../h/socket.h"
8: #include "../h/dir.h"
9: #include "../h/user.h"
10: #include "../h/ioctl.h"
11: #include "../h/errno.h"
12:
13: #include "../net/if.h"
14: #include "../net/af.h"
15: #include "../net/route.h"
16:
17: int rttrash; /* routes not in table but not freed */
18: struct sockaddr wildcard; /* zero valued cookie for wildcard searches */
19:
20: /*
21: * Packet routing routines.
22: */
23: rtalloc(ro)
24: register struct route *ro;
25: {
26: register struct rtentry *rt;
27: register struct mbuf *m;
28: register u_long hash;
29: struct sockaddr *dst = &ro->ro_dst;
30: int (*match)(), doinghost;
31: struct afhash h;
32: u_int af = dst->sa_family;
33: struct rtentry *rtmin;
34: struct mbuf **table;
35:
36: if (ro->ro_rt && ro->ro_rt->rt_ifp) /* XXX */
37: return;
38: if (af >= AF_MAX)
39: return;
40: (*afswitch[af].af_hash)(dst, &h);
41: rtmin = 0;
42: match = afswitch[af].af_netmatch;
43: hash = h.afh_hosthash, table = rthost, doinghost = 1;
44: again:
45: for (m = table[hash % RTHASHSIZ]; m; m = m->m_next) {
46: rt = mtod(m, struct rtentry *);
47: if (rt->rt_hash != hash)
48: continue;
49: if ((rt->rt_flags & RTF_UP) == 0 ||
50: (rt->rt_ifp->if_flags & IFF_UP) == 0)
51: continue;
52: if (doinghost) {
53: if (bcmp((caddr_t)&rt->rt_dst, (caddr_t)dst,
54: sizeof (*dst)))
55: continue;
56: } else {
57: if (rt->rt_dst.sa_family != af ||
58: !(*match)(&rt->rt_dst, dst))
59: continue;
60: }
61: if (rtmin == 0 || rt->rt_use < rtmin->rt_use)
62: rtmin = rt;
63: }
64: if (rtmin == 0 && doinghost) {
65: doinghost = 0;
66: hash = h.afh_nethash, table = rtnet;
67: goto again;
68: }
69: /*
70: * Check for wildcard gateway, by convention network 0.
71: */
72: if (rtmin == 0 && dst != &wildcard) {
73: dst = &wildcard, hash = 0;
74: goto again;
75: }
76: ro->ro_rt = rtmin;
77: if (rtmin == 0) {
78: rtstat.rts_unreach++;
79: return;
80: }
81: rtmin->rt_refcnt++;
82: if (dst == &wildcard)
83: rtstat.rts_wildcard++;
84: }
85:
86: rtfree(rt)
87: register struct rtentry *rt;
88: {
89:
90: if (rt == 0)
91: panic("rtfree");
92: rt->rt_refcnt--;
93: if (rt->rt_refcnt == 0 && (rt->rt_flags&RTF_UP) == 0) {
94: rttrash--;
95: (void) m_free(dtom(rt));
96: }
97: }
98:
99: /*
100: * Force a routing table entry to the specified
101: * destination to go through the given gateway.
102: * Normally called as a result of a routing redirect
103: * message from the network layer.
104: *
105: * N.B.: must be called at splnet or higher
106: *
107: * Should notify all parties with a reference to
108: * the route that it's changed (so, for instance,
109: * current round trip time estimates could be flushed),
110: * but we have no back pointers at the moment.
111: */
112: rtredirect(dst, gateway)
113: struct sockaddr *dst, *gateway;
114: {
115: struct route ro;
116: register struct rtentry *rt;
117:
118: /* verify the gateway is directly reachable */
119: if (if_ifwithnet(gateway) == 0) {
120: rtstat.rts_badredirect++;
121: return;
122: }
123: ro.ro_dst = *dst;
124: ro.ro_rt = 0;
125: rtalloc(&ro);
126: rt = ro.ro_rt;
127: /*
128: * Create a new entry if we just got back a wildcard entry
129: * or the the lookup failed. This is necessary for hosts
130: * which use routing redirects generated by smart gateways
131: * to dynamically build the routing tables.
132: */
133: if (rt &&
134: (*afswitch[dst->sa_family].af_netmatch)(&wildcard, &rt->rt_dst)) {
135: rtfree(rt);
136: rt = 0;
137: }
138: if (rt == 0) {
139: rtinit(dst, gateway, RTF_GATEWAY);
140: rtstat.rts_dynamic++;
141: return;
142: }
143: /*
144: * Don't listen to the redirect if it's
145: * for a route to an interface.
146: */
147: if (rt->rt_flags & RTF_GATEWAY) {
148: /*
149: * Smash the current notion of the gateway to
150: * this destination. This is probably not right,
151: * as it's conceivable a flurry of redirects could
152: * cause the gateway value to fluctuate wildly during
153: * dynamic routing reconfiguration.
154: */
155: rt->rt_gateway = *gateway;
156: rtfree(rt);
157: rtstat.rts_newgateway++;
158: return;
159: }
160: }
161:
162: /*
163: * Routing table ioctl interface.
164: */
165: rtioctl(cmd, data)
166: int cmd;
167: caddr_t data;
168: {
169:
170: if (cmd != SIOCADDRT && cmd != SIOCDELRT)
171: return (EINVAL);
172: if (!suser())
173: return (u.u_error);
174: return (rtrequest(cmd, (struct rtentry *)data));
175: }
176:
177: /*
178: * Carry out a request to change the routing table. Called by
179: * interfaces at boot time to make their ``local routes'' known,
180: * for ioctl's, and as the result of routing redirects.
181: */
182: rtrequest(req, entry)
183: int req;
184: register struct rtentry *entry;
185: {
186: register struct mbuf *m, **mprev;
187: register struct rtentry *rt;
188: struct afhash h;
189: int s, error = 0, (*match)();
190: u_int af;
191: u_long hash;
192: struct ifnet *ifp;
193:
194: af = entry->rt_dst.sa_family;
195: if (af >= AF_MAX)
196: return (EAFNOSUPPORT);
197: (*afswitch[af].af_hash)(&entry->rt_dst, &h);
198: if (entry->rt_flags & RTF_HOST) {
199: hash = h.afh_hosthash;
200: mprev = &rthost[hash % RTHASHSIZ];
201: } else {
202: hash = h.afh_nethash;
203: mprev = &rtnet[hash % RTHASHSIZ];
204: }
205: match = afswitch[af].af_netmatch;
206: s = splimp();
207: for (; m = *mprev; mprev = &m->m_next) {
208: rt = mtod(m, struct rtentry *);
209: if (rt->rt_hash != hash)
210: continue;
211: if (entry->rt_flags & RTF_HOST) {
212: #define equal(a1, a2) \
213: (bcmp((caddr_t)(a1), (caddr_t)(a2), sizeof (struct sockaddr)) == 0)
214: if (!equal(&rt->rt_dst, &entry->rt_dst))
215: continue;
216: } else {
217: if (rt->rt_dst.sa_family != entry->rt_dst.sa_family ||
218: (*match)(&rt->rt_dst, &entry->rt_dst) == 0)
219: continue;
220: }
221: if (equal(&rt->rt_gateway, &entry->rt_gateway))
222: break;
223: }
224: switch (req) {
225:
226: case SIOCDELRT:
227: if (m == 0) {
228: error = ESRCH;
229: goto bad;
230: }
231: *mprev = m->m_next;
232: if (rt->rt_refcnt > 0) {
233: rt->rt_flags &= ~RTF_UP;
234: rttrash++;
235: m->m_next = 0;
236: } else
237: (void) m_free(m);
238: break;
239:
240: case SIOCADDRT:
241: if (m) {
242: error = EEXIST;
243: goto bad;
244: }
245: ifp = if_ifwithaddr(&entry->rt_gateway);
246: if (ifp == 0) {
247: ifp = if_ifwithnet(&entry->rt_gateway);
248: if (ifp == 0) {
249: error = ENETUNREACH;
250: goto bad;
251: }
252: }
253: m = m_get(M_DONTWAIT, MT_RTABLE);
254: if (m == 0) {
255: error = ENOBUFS;
256: goto bad;
257: }
258: *mprev = m;
259: m->m_off = MMINOFF;
260: m->m_len = sizeof (struct rtentry);
261: rt = mtod(m, struct rtentry *);
262: rt->rt_hash = hash;
263: rt->rt_dst = entry->rt_dst;
264: rt->rt_gateway = entry->rt_gateway;
265: rt->rt_flags =
266: RTF_UP | (entry->rt_flags & (RTF_HOST|RTF_GATEWAY));
267: rt->rt_refcnt = 0;
268: rt->rt_use = 0;
269: rt->rt_ifp = ifp;
270: break;
271: }
272: bad:
273: splx(s);
274: return (error);
275: }
276:
277: /*
278: * Set up a routing table entry, normally
279: * for an interface.
280: */
281: rtinit(dst, gateway, flags)
282: struct sockaddr *dst, *gateway;
283: int flags;
284: {
285: struct rtentry route;
286: int cmd;
287:
288: if (flags == -1) {
289: cmd = (int)SIOCDELRT;
290: flags = 0;
291: } else {
292: cmd = (int)SIOCADDRT;
293: }
294: bzero((caddr_t)&route, sizeof (route));
295: route.rt_dst = *dst;
296: route.rt_gateway = *gateway;
297: route.rt_flags = flags;
298: (void) rtrequest(cmd, &route);
299: }
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