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1.1 root 1: /* route.c 6.1 83/07/29 */
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 unsigned 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, flags)
113: struct sockaddr *dst, *gateway;
114: int flags;
115: {
116: struct route ro;
117: register struct rtentry *rt;
118:
119: /* verify the gateway is directly reachable */
120: if (if_ifwithnet(gateway) == 0) {
121: rtstat.rts_badredirect++;
122: return;
123: }
124: ro.ro_dst = *dst;
125: ro.ro_rt = 0;
126: rtalloc(&ro);
127: rt = ro.ro_rt;
128: /*
129: * Create a new entry if we just got back a wildcard entry
130: * or the the lookup failed. This is necessary for hosts
131: * which use routing redirects generated by smart gateways
132: * to dynamically build the routing tables.
133: */
134: if (rt &&
135: (*afswitch[dst->sa_family].af_netmatch)(&wildcard, &rt->rt_dst)) {
136: rtfree(rt);
137: rt = 0;
138: }
139: if (rt == 0) {
140: rtinit(dst, gateway, RTF_GATEWAY);
141: rtstat.rts_dynamic++;
142: return;
143: }
144: /*
145: * Don't listen to the redirect if it's
146: * for a route to an interface.
147: */
148: if ((rt->rt_flags & (RTF_GATEWAY|RTF_HOST)) != flags) {
149: rtfree(rt);
150: if (flags & RTF_HOST) {
151: rtinit(dst, gateway, flags);
152: rtstat.rts_newgateway++;
153: }
154: return;
155: }
156: /*
157: * Smash the current notion of the gateway to
158: * this destination. This is probably not right,
159: * as it's conceivable a flurry of redirects could
160: * cause the gateway value to fluctuate wildly during
161: * dynamic routing reconfiguration.
162: */
163: rt->rt_gateway = *gateway;
164: rtfree(rt);
165: rtstat.rts_newgateway++;
166: return;
167: }
168:
169: /*
170: * Routing table ioctl interface.
171: */
172: rtioctl(cmd, data)
173: int cmd;
174: caddr_t data;
175: {
176:
177: if (cmd != SIOCADDRT && cmd != SIOCDELRT)
178: return (EINVAL);
179: if (!suser())
180: return (u.u_error);
181: return (rtrequest(cmd, (struct rtentry *)data));
182: }
183:
184: /*
185: * Carry out a request to change the routing table. Called by
186: * interfaces at boot time to make their ``local routes'' known,
187: * for ioctl's, and as the result of routing redirects.
188: */
189: rtrequest(req, entry)
190: int req;
191: register struct rtentry *entry;
192: {
193: register struct mbuf *m, **mprev;
194: register struct rtentry *rt;
195: struct afhash h;
196: int s, error = 0, (*match)();
197: u_int af;
198: struct ifnet *ifp;
199: register unsigned hash;
200:
201: af = entry->rt_dst.sa_family;
202: if (af >= AF_MAX)
203: return (EAFNOSUPPORT);
204: (*afswitch[af].af_hash)(&entry->rt_dst, &h);
205: if (entry->rt_flags & RTF_HOST) {
206: hash = h.afh_hosthash;
207: mprev = &rthost[hash % RTHASHSIZ];
208: } else {
209: hash = h.afh_nethash;
210: mprev = &rtnet[hash % RTHASHSIZ];
211: }
212: match = afswitch[af].af_netmatch;
213: s = splimp();
214: for (; m = *mprev; mprev = &m->m_next) {
215: rt = mtod(m, struct rtentry *);
216: if (rt->rt_hash != hash)
217: continue;
218: if (entry->rt_flags & RTF_HOST) {
219: #define equal(a1, a2) \
220: (bcmp((caddr_t)(a1), (caddr_t)(a2), sizeof (struct sockaddr)) == 0)
221: if (!equal(&rt->rt_dst, &entry->rt_dst))
222: continue;
223: } else {
224: if (rt->rt_dst.sa_family != entry->rt_dst.sa_family ||
225: (*match)(&rt->rt_dst, &entry->rt_dst) == 0)
226: continue;
227: }
228: if (equal(&rt->rt_gateway, &entry->rt_gateway))
229: break;
230: }
231: switch (req) {
232:
233: case SIOCDELRT:
234: if (m == 0) {
235: error = ESRCH;
236: goto bad;
237: }
238: *mprev = m->m_next;
239: if (rt->rt_refcnt > 0) {
240: rt->rt_flags &= ~RTF_UP;
241: rttrash++;
242: m->m_next = 0;
243: } else
244: (void) m_free(m);
245: break;
246:
247: case SIOCADDRT:
248: if (m) {
249: error = EEXIST;
250: goto bad;
251: }
252: ifp = if_ifwithaddr(&entry->rt_gateway);
253: if (ifp == 0) {
254: ifp = if_ifwithnet(&entry->rt_gateway);
255: if (ifp == 0) {
256: error = ENETUNREACH;
257: goto bad;
258: }
259: }
260: m = m_get(M_DONTWAIT, MT_RTABLE);
261: MBUFNULL(2, m); /* for debugging */
262: if (m == 0) {
263: error = ENOBUFS;
264: goto bad;
265: }
266: *mprev = m;
267: m->m_off = MMINOFF;
268: m->m_len = sizeof (struct rtentry);
269: rt = mtod(m, struct rtentry *);
270: rt->rt_hash = hash;
271: rt->rt_dst = entry->rt_dst;
272: rt->rt_gateway = entry->rt_gateway;
273: rt->rt_flags =
274: RTF_UP | (entry->rt_flags & (RTF_HOST|RTF_GATEWAY));
275: rt->rt_refcnt = 0;
276: rt->rt_use = 0;
277: rt->rt_ifp = ifp;
278: break;
279: }
280: bad:
281: splx(s);
282: return (error);
283: }
284:
285: /*
286: * Set up a routing table entry, normally
287: * for an interface.
288: */
289: rtinit(dst, gateway, flags)
290: struct sockaddr *dst, *gateway;
291: int flags;
292: {
293: struct rtentry route;
294: int cmd;
295:
296: if (flags == -1) {
297: cmd = (int)SIOCDELRT;
298: flags = 0;
299: } else {
300: cmd = (int)SIOCADDRT;
301: }
302: bzero((caddr_t)&route, sizeof (route));
303: route.rt_dst = *dst;
304: route.rt_gateway = *gateway;
305: route.rt_flags = flags;
306: (void) rtrequest(cmd, &route);
307: }
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