xref: /netbsd-src/sys/netinet6/in6_src.c (revision 481fca6e59249d8ffcf24fef7cfbe7b131bfb080)
1 /*	$NetBSD: in6_src.c,v 1.2 2000/07/07 15:54:19 itojun Exp $	*/
2 /*	$KAME: in6_src.c,v 1.27 2000/06/21 08:07:13 itojun Exp $	*/
3 
4 /*
5  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the name of the project nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 /*
34  * Copyright (c) 1982, 1986, 1991, 1993
35  *	The Regents of the University of California.  All rights reserved.
36  *
37  * Redistribution and use in source and binary forms, with or without
38  * modification, are permitted provided that the following conditions
39  * are met:
40  * 1. Redistributions of source code must retain the above copyright
41  *    notice, this list of conditions and the following disclaimer.
42  * 2. Redistributions in binary form must reproduce the above copyright
43  *    notice, this list of conditions and the following disclaimer in the
44  *    documentation and/or other materials provided with the distribution.
45  * 3. All advertising materials mentioning features or use of this software
46  *    must display the following acknowledgement:
47  *	This product includes software developed by the University of
48  *	California, Berkeley and its contributors.
49  * 4. Neither the name of the University nor the names of its contributors
50  *    may be used to endorse or promote products derived from this software
51  *    without specific prior written permission.
52  *
53  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
54  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
55  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
56  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
57  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
58  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
59  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
60  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
61  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
62  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
63  * SUCH DAMAGE.
64  *
65  *	@(#)in_pcb.c	8.2 (Berkeley) 1/4/94
66  */
67 
68 #include "opt_inet.h"
69 
70 #include <sys/param.h>
71 #include <sys/systm.h>
72 #include <sys/malloc.h>
73 #include <sys/mbuf.h>
74 #include <sys/protosw.h>
75 #include <sys/socket.h>
76 #include <sys/socketvar.h>
77 #include <sys/ioctl.h>
78 #include <sys/errno.h>
79 #include <sys/time.h>
80 #include <sys/proc.h>
81 
82 #include <net/if.h>
83 #include <net/route.h>
84 
85 #include <netinet/in.h>
86 #include <netinet/in_var.h>
87 #include <netinet/in_systm.h>
88 #include <netinet/ip.h>
89 #include <netinet/in_pcb.h>
90 #include <netinet6/in6_var.h>
91 #include <netinet/ip6.h>
92 #include <netinet6/in6_pcb.h>
93 #include <netinet6/ip6_var.h>
94 #include <netinet6/nd6.h>
95 #ifdef ENABLE_DEFAULT_SCOPE
96 #include <netinet6/scope6_var.h>
97 #endif
98 
99 #include <net/net_osdep.h>
100 
101 #include "loop.h"
102 extern struct ifnet loif[NLOOP];
103 
104 /*
105  * Return an IPv6 address, which is the most appropriate for given
106  * destination and user specified options.
107  * If necessary, this function lookups the routing table and return
108  * an entry to the caller for later use.
109  */
110 struct in6_addr *
111 in6_selectsrc(dstsock, opts, mopts, ro, laddr, errorp)
112 	struct sockaddr_in6 *dstsock;
113 	struct ip6_pktopts *opts;
114 	struct ip6_moptions *mopts;
115 	struct route_in6 *ro;
116 	struct in6_addr *laddr;
117 	int *errorp;
118 {
119 	struct in6_addr *dst;
120 	struct in6_ifaddr *ia6 = 0;
121 	struct in6_pktinfo *pi = NULL;
122 
123 	dst = &dstsock->sin6_addr;
124 	*errorp = 0;
125 
126 	/*
127 	 * If the source address is explicitly specified by the caller,
128 	 * use it.
129 	 */
130 	if (opts && (pi = opts->ip6po_pktinfo) &&
131 	    !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr))
132 		return(&pi->ipi6_addr);
133 
134 	/*
135 	 * If the source address is not specified but the socket(if any)
136 	 * is already bound, use the bound address.
137 	 */
138 	if (laddr && !IN6_IS_ADDR_UNSPECIFIED(laddr))
139 		return(laddr);
140 
141 	/*
142 	 * If the caller doesn't specify the source address but
143 	 * the outgoing interface, use an address associated with
144 	 * the interface.
145 	 */
146 	if (pi && pi->ipi6_ifindex) {
147 		/* XXX boundary check is assumed to be already done. */
148 		ia6 = in6_ifawithscope(ifindex2ifnet[pi->ipi6_ifindex],
149 				       dst);
150 		if (ia6 == 0) {
151 			*errorp = EADDRNOTAVAIL;
152 			return(0);
153 		}
154 		return(&satosin6(&ia6->ia_addr)->sin6_addr);
155 	}
156 
157 	/*
158 	 * If the destination address is a link-local unicast address or
159 	 * a multicast address, and if the outgoing interface is specified
160 	 * by the sin6_scope_id filed, use an address associated with the
161 	 * interface.
162 	 * XXX: We're now trying to define more specific semantics of
163 	 *      sin6_scope_id field, so this part will be rewritten in
164 	 *      the near future.
165 	 */
166 	if ((IN6_IS_ADDR_LINKLOCAL(dst) || IN6_IS_ADDR_MULTICAST(dst)) &&
167 	    dstsock->sin6_scope_id) {
168 		/*
169 		 * I'm not sure if boundary check for scope_id is done
170 		 * somewhere...
171 		 */
172 		if (dstsock->sin6_scope_id < 0 ||
173 		    if_index < dstsock->sin6_scope_id) {
174 			*errorp = ENXIO; /* XXX: better error? */
175 			return(0);
176 		}
177 		ia6 = in6_ifawithscope(ifindex2ifnet[dstsock->sin6_scope_id],
178 				       dst);
179 		if (ia6 == 0) {
180 			*errorp = EADDRNOTAVAIL;
181 			return(0);
182 		}
183 		return(&satosin6(&ia6->ia_addr)->sin6_addr);
184 	}
185 
186 	/*
187 	 * If the destination address is a multicast address and
188 	 * the outgoing interface for the address is specified
189 	 * by the caller, use an address associated with the interface.
190 	 * There is a sanity check here; if the destination has node-local
191 	 * scope, the outgoing interfacde should be a loopback address.
192 	 * Even if the outgoing interface is not specified, we also
193 	 * choose a loopback interface as the outgoing interface.
194 	 */
195 	if (IN6_IS_ADDR_MULTICAST(dst)) {
196 		struct ifnet *ifp = mopts ? mopts->im6o_multicast_ifp : NULL;
197 
198 		if (ifp == NULL && IN6_IS_ADDR_MC_NODELOCAL(dst)) {
199 			ifp = &loif[0];
200 		}
201 
202 		if (ifp) {
203 			ia6 = in6_ifawithscope(ifp, dst);
204 			if (ia6 == 0) {
205 				*errorp = EADDRNOTAVAIL;
206 				return(0);
207 			}
208 			return(&satosin6(&ia6->ia_addr)->sin6_addr);
209 		}
210 	}
211 
212 	/*
213 	 * If the next hop address for the packet is specified
214 	 * by caller, use an address associated with the route
215 	 * to the next hop.
216 	 */
217 	{
218 		struct sockaddr_in6 *sin6_next;
219 		struct rtentry *rt;
220 
221 		if (opts && opts->ip6po_nexthop) {
222 			sin6_next = satosin6(opts->ip6po_nexthop);
223 			rt = nd6_lookup(&sin6_next->sin6_addr, 1, NULL);
224 			if (rt) {
225 				ia6 = in6_ifawithscope(rt->rt_ifp, dst);
226 				if (ia6 == 0)
227 					ia6 = ifatoia6(rt->rt_ifa);
228 			}
229 			if (ia6 == 0) {
230 				*errorp = EADDRNOTAVAIL;
231 				return(0);
232 			}
233 			return(&satosin6(&ia6->ia_addr)->sin6_addr);
234 		}
235 	}
236 
237 	/*
238 	 * If route is known or can be allocated now,
239 	 * our src addr is taken from the i/f, else punt.
240 	 */
241 	if (ro) {
242 		if (ro->ro_rt &&
243 		    !IN6_ARE_ADDR_EQUAL(&satosin6(&ro->ro_dst)->sin6_addr, dst)) {
244 			RTFREE(ro->ro_rt);
245 			ro->ro_rt = (struct rtentry *)0;
246 		}
247 		if (ro->ro_rt == (struct rtentry *)0 ||
248 		    ro->ro_rt->rt_ifp == (struct ifnet *)0) {
249 			/* No route yet, so try to acquire one */
250 			bzero(&ro->ro_dst, sizeof(struct sockaddr_in6));
251 			ro->ro_dst.sin6_family = AF_INET6;
252 			ro->ro_dst.sin6_len = sizeof(struct sockaddr_in6);
253 			ro->ro_dst.sin6_addr = *dst;
254 			ro->ro_dst.sin6_scope_id = dstsock->sin6_scope_id;
255 			if (IN6_IS_ADDR_MULTICAST(dst)) {
256 				ro->ro_rt = rtalloc1(&((struct route *)ro)
257 						     ->ro_dst, 0);
258 			} else {
259 				rtalloc((struct route *)ro);
260 			}
261 		}
262 
263 		/*
264 		 * in_pcbconnect() checks out IFF_LOOPBACK to skip using
265 		 * the address. But we don't know why it does so.
266 		 * It is necessary to ensure the scope even for lo0
267 		 * so doesn't check out IFF_LOOPBACK.
268 		 */
269 
270 		if (ro->ro_rt) {
271 			ia6 = in6_ifawithscope(ro->ro_rt->rt_ifa->ifa_ifp, dst);
272 			if (ia6 == 0) /* xxx scope error ?*/
273 				ia6 = ifatoia6(ro->ro_rt->rt_ifa);
274 		}
275 #if 0
276 		/*
277 		 * xxx The followings are necessary? (kazu)
278 		 * I don't think so.
279 		 * It's for SO_DONTROUTE option in IPv4.(jinmei)
280 		 */
281 		if (ia6 == 0) {
282 			struct sockaddr_in6 sin6 = {sizeof(sin6), AF_INET6, 0};
283 
284 			sin6->sin6_addr = *dst;
285 
286 			ia6 = ifatoia6(ifa_ifwithdstaddr(sin6tosa(&sin6)));
287 			if (ia6 == 0)
288 				ia6 = ifatoia6(ifa_ifwithnet(sin6tosa(&sin6)));
289 			if (ia6 == 0)
290 				return(0);
291 			return(&satosin6(&ia6->ia_addr)->sin6_addr);
292 		}
293 #endif /* 0 */
294 		if (ia6 == 0) {
295 			*errorp = EHOSTUNREACH;	/* no route */
296 			return(0);
297 		}
298 		return(&satosin6(&ia6->ia_addr)->sin6_addr);
299 	}
300 
301 	*errorp = EADDRNOTAVAIL;
302 	return(0);
303 }
304 
305 /*
306  * Default hop limit selection. The precedence is as follows:
307  * 1. Hoplimit value specified via ioctl.
308  * 2. (If the outgoing interface is detected) the current
309  *     hop limit of the interface specified by router advertisement.
310  * 3. The system default hoplimit.
311 */
312 int
313 in6_selecthlim(in6p, ifp)
314 	struct in6pcb *in6p;
315 	struct ifnet *ifp;
316 {
317 	if (in6p && in6p->in6p_hops >= 0)
318 		return(in6p->in6p_hops);
319 	else if (ifp)
320 		return(nd_ifinfo[ifp->if_index].chlim);
321 	else
322 		return(ip6_defhlim);
323 }
324 
325 /*
326  * Find an empty port and set it to the specified PCB.
327  */
328 int
329 in6_pcbsetport(laddr, in6p)
330 	struct in6_addr *laddr;
331 	struct in6pcb *in6p;
332 {
333 	struct socket *so = in6p->in6p_socket;
334 	struct in6pcb *head = in6p->in6p_head;
335 	u_int16_t last_port, lport = 0;
336 	int wild = 0;
337 	void *t;
338 	u_int16_t min, max;
339 	struct proc *p = curproc;		/* XXX */
340 
341 	/* XXX: this is redundant when called from in6_pcbbind */
342 	if ((so->so_options & (SO_REUSEADDR|SO_REUSEPORT)) == 0 &&
343 	   ((so->so_proto->pr_flags & PR_CONNREQUIRED) == 0 ||
344 	    (so->so_options & SO_ACCEPTCONN) == 0))
345 		wild = IN6PLOOKUP_WILDCARD;
346 
347 	if (in6p->in6p_flags & IN6P_LOWPORT) {
348 		if (p == 0 || (suser(p->p_ucred, &p->p_acflag) != 0))
349 			return (EACCES);
350 		min = IPV6PORT_RESERVEDMIN;
351 		max = IPV6PORT_RESERVEDMAX;
352 	} else {
353 		min = IPV6PORT_ANONMIN;
354 		max = IPV6PORT_ANONMAX;
355 	}
356 
357 	/* value out of range */
358 	if (head->in6p_lport < min)
359 		head->in6p_lport = min;
360 	else if (head->in6p_lport > max)
361 		head->in6p_lport = min;
362 	last_port = head->in6p_lport;
363 	goto startover;	/*to randomize*/
364 	for (;;) {
365 		lport = htons(head->in6p_lport);
366 		if (IN6_IS_ADDR_V4MAPPED(laddr)) {
367 #if 0
368 			t = in_pcblookup_bind(&tcbtable,
369 					      (struct in_addr *)&in6p->in6p_laddr.s6_addr32[3],
370 					      lport);
371 #else
372 			t = NULL;
373 #endif
374 		} else {
375 			t = in6_pcblookup(head, &zeroin6_addr, 0, laddr,
376 					  lport, wild);
377 		}
378 		if (t == 0)
379 			break;
380 	  startover:
381 		if (head->in6p_lport >= max)
382 			head->in6p_lport = min;
383 		else
384 			head->in6p_lport++;
385 		if (head->in6p_lport == last_port)
386 			return (EADDRINUSE);
387 	}
388 
389 	in6p->in6p_lport = lport;
390 	return(0);		/* success */
391 }
392 
393 /*
394  * generate kernel-internal form (scopeid embedded into s6_addr16[1]).
395  * If the address scope of is link-local, embed the interface index in the
396  * address.  The routine determines our precedence
397  * between advanced API scope/interface specification and basic API
398  * specification.
399  *
400  * this function should be nuked in the future, when we get rid of
401  * embedded scopeid thing.
402  *
403  * XXX actually, it is over-specification to return ifp against sin6_scope_id.
404  * there can be multiple interfaces that belong to a particular scope zone
405  * (in specification, we have 1:N mapping between a scope zone and interfaces).
406  * we may want to change the function to return something other than ifp.
407  */
408 int
409 in6_embedscope(in6, sin6, in6p, ifpp)
410 	struct in6_addr *in6;
411 	const struct sockaddr_in6 *sin6;
412 	struct in6pcb *in6p;
413 	struct ifnet **ifpp;
414 {
415 	struct ifnet *ifp = NULL;
416 	u_int32_t scopeid;
417 
418 	*in6 = sin6->sin6_addr;
419 	scopeid = sin6->sin6_scope_id;
420 	if (ifpp)
421 		*ifpp = NULL;
422 
423 	/*
424 	 * don't try to read sin6->sin6_addr beyond here, since the caller may
425 	 * ask us to overwrite existing sockaddr_in6
426 	 */
427 
428 #ifdef ENABLE_DEFAULT_SCOPE
429 	if (scopeid == 0)
430 		scopeid = scope6_addr2default(in6);
431 #endif
432 
433 	if (IN6_IS_SCOPE_LINKLOCAL(in6)) {
434 		struct in6_pktinfo *pi;
435 
436 		/*
437 		 * KAME assumption: link id == interface id
438 		 */
439 
440 		if (in6p && in6p->in6p_outputopts &&
441 		    (pi = in6p->in6p_outputopts->ip6po_pktinfo) &&
442 		    pi->ipi6_ifindex) {
443 			ifp = ifindex2ifnet[pi->ipi6_ifindex];
444 			in6->s6_addr16[1] = htons(pi->ipi6_ifindex);
445 		} else if (in6p && IN6_IS_ADDR_MULTICAST(in6) &&
446 			   in6p->in6p_moptions &&
447 			   in6p->in6p_moptions->im6o_multicast_ifp) {
448 			ifp = in6p->in6p_moptions->im6o_multicast_ifp;
449 			in6->s6_addr16[1] = htons(ifp->if_index);
450 		} else if (scopeid) {
451 			/* boundary check */
452 			if (scopeid < 0 || if_index < scopeid)
453 				return ENXIO;  /* XXX EINVAL? */
454 			ifp = ifindex2ifnet[scopeid];
455 			/*XXX assignment to 16bit from 32bit variable */
456 			in6->s6_addr16[1] = htons(scopeid & 0xffff);
457 		}
458 
459 		if (ifpp)
460 			*ifpp = ifp;
461 	}
462 
463 	return 0;
464 }
465 
466 /*
467  * generate standard sockaddr_in6 from embedded form.
468  * touches sin6_addr and sin6_scope_id only.
469  *
470  * this function should be nuked in the future, when we get rid of
471  * embedded scopeid thing.
472  */
473 int
474 in6_recoverscope(sin6, in6, ifp)
475 	struct sockaddr_in6 *sin6;
476 	const struct in6_addr *in6;
477 	struct ifnet *ifp;
478 {
479 	u_int32_t scopeid;
480 
481 	sin6->sin6_addr = *in6;
482 
483 	/*
484 	 * don't try to read *in6 beyond here, since the caller may
485 	 * ask us to overwrite existing sockaddr_in6
486 	 */
487 
488 	sin6->sin6_scope_id = 0;
489 	if (IN6_IS_SCOPE_LINKLOCAL(in6)) {
490 		/*
491 		 * KAME assumption: link id == interface id
492 		 */
493 		scopeid = ntohs(sin6->sin6_addr.s6_addr16[1]);
494 		if (scopeid) {
495 			/* sanity check */
496 			if (scopeid < 0 || if_index < scopeid)
497 				return ENXIO;
498 #ifndef FAKE_LOOPBACK_IF
499 			if (ifp && (ifp->if_flags & IFF_LOOPBACK) == 0 &&
500 			    ifp->if_index != scopeid) {
501 				return ENXIO;
502 			}
503 #else
504 			if (ifp && ifp->if_index != scopeid)
505 				return ENXIO;
506 #endif
507 			sin6->sin6_addr.s6_addr16[1] = 0;
508 			sin6->sin6_scope_id = scopeid;
509 		}
510 	}
511 
512 	return 0;
513 }
514