xref: /netbsd-src/sys/net/route.c (revision 811e6386f8c5e4a3521c7003da29ec8673e344fa)
1 /*
2  * Copyright (c) 1980, 1986, 1991 Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  *	@(#)route.c	7.22 (Berkeley) 6/27/91
34  *
35  * PATCHES MAGIC                LEVEL   PATCH THAT GOT US HERE
36  * --------------------         -----   ----------------------
37  * CURRENT PATCH LEVEL:         1       00095
38  * --------------------         -----   ----------------------
39  *
40  * 27 Feb 93    Charles Hannum & ???	Proper initialization of *rt
41  *
42  */
43 
44 #include "param.h"
45 #include "systm.h"
46 #include "proc.h"
47 #include "mbuf.h"
48 #include "socket.h"
49 #include "socketvar.h"
50 #include "domain.h"
51 #include "protosw.h"
52 #include "ioctl.h"
53 
54 #include "if.h"
55 #include "af.h"
56 #include "route.h"
57 #include "raw_cb.h"
58 
59 #include "../netinet/in.h"
60 #include "../netinet/in_var.h"
61 
62 #ifdef NS
63 #include "../netns/ns.h"
64 #endif
65 #include "machine/mtpr.h"
66 #include "netisr.h"
67 
68 #define	SA(p) ((struct sockaddr *)(p))
69 
70 int	rttrash;		/* routes not in table but not freed */
71 struct	sockaddr wildcard;	/* zero valued cookie for wildcard searches */
72 int	rthashsize = RTHASHSIZ;	/* for netstat, etc. */
73 
74 static int rtinits_done = 0;
75 struct radix_node_head *ns_rnhead, *in_rnhead;
76 struct radix_node *rn_match(), *rn_delete(), *rn_addroute();
77 
78 rtinitheads()
79 {
80 	if (rtinits_done == 0 &&
81 #ifdef NS
82 	    rn_inithead(&ns_rnhead, 16, AF_NS) &&
83 #endif
84 	    rn_inithead(&in_rnhead, 32, AF_INET))
85 		rtinits_done = 1;
86 }
87 
88 /*
89  * Packet routing routines.
90  */
91 rtalloc(ro)
92 	register struct route *ro;
93 {
94 	if (ro->ro_rt && ro->ro_rt->rt_ifp && (ro->ro_rt->rt_flags & RTF_UP))
95 		return;				 /* XXX */
96 	ro->ro_rt = rtalloc1(&ro->ro_dst, 1);
97 }
98 
99 struct rtentry *
100 rtalloc1(dst, report)
101 	register struct sockaddr *dst;
102 	int  report;
103 {
104 	register struct radix_node_head *rnh;
105 	register struct rtentry *rt;
106 	register struct radix_node *rn;
107 	struct rtentry *newrt = 0;
108 	int  s = splnet(), err = 0, msgtype = RTM_MISS;
109 
110 	for (rnh = radix_node_head; rnh && (dst->sa_family != rnh->rnh_af); )
111 		rnh = rnh->rnh_next;
112 	if (rnh && rnh->rnh_treetop &&
113 	    (rn = rn_match((caddr_t)dst, rnh->rnh_treetop)) &&
114 	    ((rn->rn_flags & RNF_ROOT) == 0)) {
115 		newrt = rt = (struct rtentry *)rn;
116 		if (report && (rt->rt_flags & RTF_CLONING)) {
117 			if ((err = rtrequest(RTM_RESOLVE, dst, SA(0),
118 					      SA(0), 0, &newrt)) ||
119 			    ((rt->rt_flags & RTF_XRESOLVE)
120 			      && (msgtype = RTM_RESOLVE))) /* intended! */
121 			    goto miss;
122 		} else
123 			rt->rt_refcnt++;
124 	} else {
125 		rtstat.rts_unreach++;
126 	miss:	if (report)
127 			rt_missmsg(msgtype, dst, SA(0), SA(0), SA(0), 0, err);
128 	}
129 	splx(s);
130 	return (newrt);
131 }
132 
133 rtfree(rt)
134 	register struct rtentry *rt;
135 {
136 	register struct ifaddr *ifa;
137 	if (rt == 0)
138 		panic("rtfree");
139 	rt->rt_refcnt--;
140 	if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_UP) == 0) {
141 		rttrash--;
142 		if (rt->rt_nodes->rn_flags & (RNF_ACTIVE | RNF_ROOT))
143 			panic ("rtfree 2");
144 		free((caddr_t)rt, M_RTABLE);
145 	}
146 }
147 
148 /*
149  * Force a routing table entry to the specified
150  * destination to go through the given gateway.
151  * Normally called as a result of a routing redirect
152  * message from the network layer.
153  *
154  * N.B.: must be called at splnet
155  *
156  */
157 rtredirect(dst, gateway, netmask, flags, src, rtp)
158 	struct sockaddr *dst, *gateway, *netmask, *src;
159 	int flags;
160 	struct rtentry **rtp;
161 {
162 	register struct rtentry *rt = 0;
163 	int error = 0;
164 	short *stat = 0;
165 
166 	/* verify the gateway is directly reachable */
167 	if (ifa_ifwithnet(gateway) == 0) {
168 		error = ENETUNREACH;
169 		goto done;
170 	}
171 	rt = rtalloc1(dst, 0);
172 	/*
173 	 * If the redirect isn't from our current router for this dst,
174 	 * it's either old or wrong.  If it redirects us to ourselves,
175 	 * we have a routing loop, perhaps as a result of an interface
176 	 * going down recently.
177 	 */
178 #define	equal(a1, a2) (bcmp((caddr_t)(a1), (caddr_t)(a2), (a1)->sa_len) == 0)
179 	if (!(flags & RTF_DONE) && rt && !equal(src, rt->rt_gateway))
180 		error = EINVAL;
181 	else if (ifa_ifwithaddr(gateway))
182 		error = EHOSTUNREACH;
183 	if (error)
184 		goto done;
185 	/*
186 	 * Create a new entry if we just got back a wildcard entry
187 	 * or the the lookup failed.  This is necessary for hosts
188 	 * which use routing redirects generated by smart gateways
189 	 * to dynamically build the routing tables.
190 	 */
191 	if ((rt == 0) || (rt_mask(rt) && rt_mask(rt)->sa_len < 2))
192 		goto create;
193 	/*
194 	 * Don't listen to the redirect if it's
195 	 * for a route to an interface.
196 	 */
197 	if (rt->rt_flags & RTF_GATEWAY) {
198 		if (((rt->rt_flags & RTF_HOST) == 0) && (flags & RTF_HOST)) {
199 			/*
200 			 * Changing from route to net => route to host.
201 			 * Create new route, rather than smashing route to net.
202 			 */
203 		create:
204 			flags |=  RTF_GATEWAY | RTF_DYNAMIC;
205 			error = rtrequest((int)RTM_ADD, dst, gateway,
206 				    SA(0), flags,
207 				    (struct rtentry **)0);
208 			stat = &rtstat.rts_dynamic;
209 		} else {
210 			/*
211 			 * Smash the current notion of the gateway to
212 			 * this destination.  Should check about netmask!!!
213 			 */
214 			if (gateway->sa_len <= rt->rt_gateway->sa_len) {
215 				Bcopy(gateway, rt->rt_gateway, gateway->sa_len);
216 				rt->rt_flags |= RTF_MODIFIED;
217 				flags |= RTF_MODIFIED;
218 				stat = &rtstat.rts_newgateway;
219 			} else
220 				error = ENOSPC;
221 		}
222 	} else
223 		error = EHOSTUNREACH;
224 done:
225 	if (rt) {
226 		if (rtp && !error)
227 			*rtp = rt;
228 		else
229 			rtfree(rt);
230 	}
231 	if (error)
232 		rtstat.rts_badredirect++;
233 	else
234 		(stat && (*stat)++);
235 	rt_missmsg(RTM_REDIRECT, dst, gateway, netmask, src, flags, error);
236 }
237 
238 /*
239 * Routing table ioctl interface.
240 */
241 rtioctl(req, data, p)
242 	int req;
243 	caddr_t data;
244 	struct proc *p;
245 {
246 #ifndef COMPAT_43
247 	return (EOPNOTSUPP);
248 #else
249 	register struct ortentry *entry = (struct ortentry *)data;
250 	int error;
251 	struct sockaddr *netmask = 0;
252 
253 	if (req == SIOCADDRT)
254 		req = RTM_ADD;
255 	else if (req == SIOCDELRT)
256 		req = RTM_DELETE;
257 	else
258 		return (EINVAL);
259 
260 	if (error = suser(p->p_ucred, &p->p_acflag))
261 		return (error);
262 #if BYTE_ORDER != BIG_ENDIAN
263 	if (entry->rt_dst.sa_family == 0 && entry->rt_dst.sa_len < 16) {
264 		entry->rt_dst.sa_family = entry->rt_dst.sa_len;
265 		entry->rt_dst.sa_len = 16;
266 	}
267 	if (entry->rt_gateway.sa_family == 0 && entry->rt_gateway.sa_len < 16) {
268 		entry->rt_gateway.sa_family = entry->rt_gateway.sa_len;
269 		entry->rt_gateway.sa_len = 16;
270 	}
271 #else
272 	if (entry->rt_dst.sa_len == 0)
273 		entry->rt_dst.sa_len = 16;
274 	if (entry->rt_gateway.sa_len == 0)
275 		entry->rt_gateway.sa_len = 16;
276 #endif
277 	if ((entry->rt_flags & RTF_HOST) == 0)
278 		switch (entry->rt_dst.sa_family) {
279 #ifdef INET
280 		case AF_INET:
281 			{
282 				extern struct sockaddr_in icmpmask;
283 				struct sockaddr_in *dst_in =
284 					(struct sockaddr_in *)&entry->rt_dst;
285 
286 				in_sockmaskof(dst_in->sin_addr, &icmpmask);
287 				netmask = (struct sockaddr *)&icmpmask;
288 			}
289 			break;
290 #endif
291 #ifdef NS
292 		case AF_NS:
293 			{
294 				extern struct sockaddr_ns ns_netmask;
295 				netmask = (struct sockaddr *)&ns_netmask;
296 			}
297 #endif
298 		}
299 	error =  rtrequest(req, &(entry->rt_dst), &(entry->rt_gateway), netmask,
300 				entry->rt_flags, (struct rtentry **)0);
301 	rt_missmsg((req == RTM_ADD ? RTM_OLDADD : RTM_OLDDEL),
302 		   &(entry->rt_dst), &(entry->rt_gateway),
303 		   netmask, SA(0), entry->rt_flags, error);
304 	return (error);
305 #endif
306 }
307 
308 struct ifaddr *
309 ifa_ifwithroute(flags, dst, gateway)
310 int	flags;
311 struct sockaddr	*dst, *gateway;
312 {
313 	register struct ifaddr *ifa;
314 	if ((flags & RTF_GATEWAY) == 0) {
315 		/*
316 		 * If we are adding a route to an interface,
317 		 * and the interface is a pt to pt link
318 		 * we should search for the destination
319 		 * as our clue to the interface.  Otherwise
320 		 * we can use the local address.
321 		 */
322 		ifa = 0;
323 		if (flags & RTF_HOST)
324 			ifa = ifa_ifwithdstaddr(dst);
325 		if (ifa == 0)
326 			ifa = ifa_ifwithaddr(gateway);
327 	} else {
328 		/*
329 		 * If we are adding a route to a remote net
330 		 * or host, the gateway may still be on the
331 		 * other end of a pt to pt link.
332 		 */
333 		ifa = ifa_ifwithdstaddr(gateway);
334 	}
335 	if (ifa == 0)
336 		ifa = ifa_ifwithnet(gateway);
337 	if (ifa == 0) {
338 		struct rtentry *rt = rtalloc1(dst, 0);
339 		if (rt == 0)
340 			return (0);
341 		rt->rt_refcnt--;
342 		if ((ifa = rt->rt_ifa) == 0)
343 			return (0);
344 	}
345 	if (ifa->ifa_addr->sa_family != dst->sa_family) {
346 		struct ifaddr *oifa = ifa, *ifaof_ifpforaddr();
347 		ifa = ifaof_ifpforaddr(dst, ifa->ifa_ifp);
348 		if (ifa == 0)
349 			ifa = oifa;
350 	}
351 	return (ifa);
352 }
353 
354 #define ROUNDUP(a) (a>0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
355 
356 rtrequest(req, dst, gateway, netmask, flags, ret_nrt)
357 	int req, flags;
358 	struct sockaddr *dst, *gateway, *netmask;
359 	struct rtentry **ret_nrt;
360 {
361 	int s = splnet(), len, error = 0;
362 	register struct rtentry *rt;
363 	register struct radix_node *rn;
364 	register struct radix_node_head *rnh;
365 	struct ifaddr *ifa, *ifa_ifwithdstaddr();
366 	struct sockaddr *ndst;
367 	u_char af = dst->sa_family;
368 #define senderr(x) { error = x ; goto bad; }
369 
370 	if (rtinits_done == 0)
371 		rtinitheads();
372 	for (rnh = radix_node_head; rnh && (af != rnh->rnh_af); )
373 		rnh = rnh->rnh_next;
374 	if (rnh == 0)
375 		senderr(ESRCH);
376 	if (flags & RTF_HOST)
377 		netmask = 0;
378 	switch (req) {
379 	case RTM_DELETE:
380 		if (ret_nrt && (rt = *ret_nrt)) {
381 			RTFREE(rt);
382 			*ret_nrt = 0;
383 		}
384 		if ((rn = rn_delete((caddr_t)dst, (caddr_t)netmask,
385 					rnh->rnh_treetop)) == 0)
386 			senderr(ESRCH);
387 		if (rn->rn_flags & (RNF_ACTIVE | RNF_ROOT))
388 			panic ("rtrequest delete");
389 		rt = (struct rtentry *)rn;
390 		rt->rt_flags &= ~RTF_UP;
391 		if ((ifa = rt->rt_ifa) && ifa->ifa_rtrequest)
392 			ifa->ifa_rtrequest(RTM_DELETE, rt, SA(0));
393 		rttrash++;
394 		if (rt->rt_refcnt <= 0)
395 			rtfree(rt);
396 		break;
397 
398 	case RTM_RESOLVE:
399 		if (ret_nrt == 0 || (rt = *ret_nrt) == 0)
400 			senderr(EINVAL);
401 		ifa = rt->rt_ifa;
402 		flags = rt->rt_flags & ~RTF_CLONING;
403 		gateway = rt->rt_gateway;
404 		if ((netmask = rt->rt_genmask) == 0)
405 			flags |= RTF_HOST;
406 		goto makeroute;
407 
408 	case RTM_ADD:
409 		if ((ifa = ifa_ifwithroute(flags, dst, gateway)) == 0)
410 			senderr(ENETUNREACH);
411 	makeroute:
412 		len = sizeof (*rt) + ROUNDUP(gateway->sa_len)
413 		    + ROUNDUP(dst->sa_len);
414 		R_Malloc(rt, struct rtentry *, len);
415 		if (rt == 0)
416 			senderr(ENOBUFS);
417 		Bzero(rt, len);
418 		ndst = (struct sockaddr *)(rt + 1);
419 		if (netmask) {
420 			rt_maskedcopy(dst, ndst, netmask);
421 		} else
422 			Bcopy(dst, ndst, dst->sa_len);
423 		rn = rn_addroute((caddr_t)ndst, (caddr_t)netmask,
424 					rnh->rnh_treetop, rt->rt_nodes);
425 		if (rn == 0) {
426 			free((caddr_t)rt, M_RTABLE);
427 			senderr(EEXIST);
428 		}
429 		rt->rt_ifa = ifa;
430 		rt->rt_ifp = ifa->ifa_ifp;
431 		rt->rt_flags = RTF_UP | flags;
432 		rt->rt_gateway = (struct sockaddr *)
433 					(rn->rn_key + ROUNDUP(dst->sa_len));
434 		Bcopy(gateway, rt->rt_gateway, gateway->sa_len);
435 		if (req == RTM_RESOLVE)
436 			rt->rt_rmx = (*ret_nrt)->rt_rmx; /* copy metrics */
437 		if (ifa->ifa_rtrequest)
438 			ifa->ifa_rtrequest(req, rt, SA(ret_nrt ? *ret_nrt : 0));
439 		if (ret_nrt) {
440 			*ret_nrt = rt;
441 			rt->rt_refcnt++;
442 		}
443 		break;
444 	}
445 bad:
446 	splx(s);
447 	return (error);
448 }
449 
450 rt_maskedcopy(src, dst, netmask)
451 struct sockaddr *src, *dst, *netmask;
452 {
453 	register u_char *cp1 = (u_char *)src;
454 	register u_char *cp2 = (u_char *)dst;
455 	register u_char *cp3 = (u_char *)netmask;
456 	u_char *cplim = cp2 + *cp3;
457 	u_char *cplim2 = cp2 + *cp1;
458 
459 	*cp2++ = *cp1++; *cp2++ = *cp1++; /* copies sa_len & sa_family */
460 	cp3 += 2;
461 	if (cplim > cplim2)
462 		cplim = cplim2;
463 	while (cp2 < cplim)
464 		*cp2++ = *cp1++ & *cp3++;
465 	if (cp2 < cplim2)
466 		bzero((caddr_t)cp2, (unsigned)(cplim2 - cp2));
467 }
468 /*
469  * Set up a routing table entry, normally
470  * for an interface.
471  */
472 rtinit(ifa, cmd, flags)
473 	register struct ifaddr *ifa;
474 	int cmd, flags;
475 {
476 	register struct rtentry *rt;
477 	register struct sockaddr *dst;
478 	register struct sockaddr *deldst;
479 	struct mbuf *m = 0;
480 	int error;
481 
482 	dst = flags & RTF_HOST ? ifa->ifa_dstaddr : ifa->ifa_addr;
483 	if (ifa->ifa_flags & IFA_ROUTE) {
484 		if ((rt = ifa->ifa_rt) && (rt->rt_flags & RTF_UP) == 0) {
485 			RTFREE(rt);
486 			ifa->ifa_rt = 0;
487 		}
488 	}
489 	if (cmd == RTM_DELETE) {
490 		if ((flags & RTF_HOST) == 0 && ifa->ifa_netmask) {
491 			m = m_get(M_WAIT, MT_SONAME);
492 			deldst = mtod(m, struct sockaddr *);
493 			rt_maskedcopy(dst, deldst, ifa->ifa_netmask);
494 			dst = deldst;
495 		}
496 		if (rt = rtalloc1(dst, 0)) {
497 			rt->rt_refcnt--;
498 			if (rt->rt_ifa != ifa) {
499 				if (m)
500 					(void) m_free(m);
501 				return (flags & RTF_HOST ? EHOSTUNREACH
502 							: ENETUNREACH);
503 			}
504 		}
505 	}
506 	error = rtrequest(cmd, dst, ifa->ifa_addr, ifa->ifa_netmask,
507 			flags | ifa->ifa_flags, &ifa->ifa_rt);
508 	if (m)
509 		(void) m_free(m);
510 	if (cmd == RTM_ADD && error == 0 && (rt = ifa->ifa_rt)
511 						&& rt->rt_ifa != ifa) {
512 		rt->rt_ifa = ifa;
513 		rt->rt_ifp = ifa->ifa_ifp;
514 	}
515 	return (error);
516 }
517