1 /*-
2 * Copyright (c) 2004 Robert N. M. Watson
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 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * Copyright (c) 1990, 1994 Regents of The University of Michigan.
27 *
28 * Permission to use, copy, modify, and distribute this software and
29 * its documentation for any purpose and without fee is hereby granted,
30 * provided that the above copyright notice appears in all copies and
31 * that both that copyright notice and this permission notice appear
32 * in supporting documentation, and that the name of The University
33 * of Michigan not be used in advertising or publicity pertaining to
34 * distribution of the software without specific, written prior
35 * permission. This software is supplied as is without expressed or
36 * implied warranties of any kind.
37 *
38 * This product includes software developed by the University of
39 * California, Berkeley and its contributors.
40 *
41 * Research Systems Unix Group
42 * The University of Michigan
43 * c/o Wesley Craig
44 * 535 W. William Street
45 * Ann Arbor, Michigan
46 * +1-313-764-2278
47 * netatalk@umich.edu
48 *
49 * $FreeBSD$
50 */
51
52 #include "opt_mac.h"
53
54 #include <sys/param.h>
55 #include <sys/kernel.h>
56 #include <sys/lock.h>
57 #include <sys/mbuf.h>
58 #include <sys/signalvar.h>
59 #include <sys/socket.h>
60 #include <sys/socketvar.h>
61 #include <sys/sx.h>
62 #include <sys/systm.h>
63 #include <net/if.h>
64 #include <net/route.h>
65
66 #include <netatalk/at.h>
67 #include <netatalk/at_var.h>
68 #include <netatalk/ddp.h>
69 #include <netatalk/ddp_var.h>
70 #include <netatalk/ddp_pcb.h>
71 #include <netatalk/at_extern.h>
72
73 #include <security/mac/mac_framework.h>
74
75 static volatile int ddp_forward = 1;
76 static volatile int ddp_firewall = 0;
77 static struct ddpstat ddpstat;
78
79 static struct route forwro;
80
81 static void ddp_input(struct mbuf *, struct ifnet *, struct elaphdr *, int);
82
83 /*
84 * Could probably merge these two code segments a little better...
85 */
86 void
87 at2intr(struct mbuf *m)
88 {
89
90 /*
91 * Phase 2 packet handling .
92 */
93 ddp_input(m, m->m_pkthdr.rcvif, NULL, 2);
94 }
95
96 void
97 at1intr(struct mbuf *m)
98 {
99 struct elaphdr *elhp, elh;
100
101 /*
102 * Phase 1 packet handling
103 */
104 if (m->m_len < SZ_ELAPHDR && ((m = m_pullup(m, SZ_ELAPHDR)) ==
105 NULL)) {
106 ddpstat.ddps_tooshort++;
107 return;
108 }
109
110 /*
111 * This seems a little dubious, but I don't know phase 1 so leave it.
112 */
113 elhp = mtod(m, struct elaphdr *);
114 m_adj(m, SZ_ELAPHDR);
115
116 if (elhp->el_type != ELAP_DDPEXTEND) {
117 bcopy((caddr_t)elhp, (caddr_t)&elh, SZ_ELAPHDR);
118 ddp_input(m, m->m_pkthdr.rcvif, &elh, 1);
119 } else
120 ddp_input(m, m->m_pkthdr.rcvif, NULL, 1);
121 }
122
123 static void
124 ddp_input(struct mbuf *m, struct ifnet *ifp, struct elaphdr *elh, int phase)
125 {
126 struct sockaddr_at from, to;
127 struct ddpshdr *dsh, ddps;
128 struct at_ifaddr *aa;
129 struct ddpehdr *deh = NULL, ddpe;
130 struct ddpcb *ddp;
131 int dlen, mlen;
132 u_short cksum = 0;
133
134 bzero((caddr_t)&from, sizeof(struct sockaddr_at));
135 bzero((caddr_t)&to, sizeof(struct sockaddr_at));
136 if (elh != NULL) {
137 /*
138 * Extract the information in the short header. Network
139 * information is defaulted to ATADDR_ANYNET and node
140 * information comes from the elh info. We must be phase 1.
141 */
142 ddpstat.ddps_short++;
143
144 if (m->m_len < sizeof(struct ddpshdr) &&
145 ((m = m_pullup(m, sizeof(struct ddpshdr))) == NULL)) {
146 ddpstat.ddps_tooshort++;
147 return;
148 }
149
150 dsh = mtod(m, struct ddpshdr *);
151 bcopy((caddr_t)dsh, (caddr_t)&ddps, sizeof(struct ddpshdr));
152 ddps.dsh_bytes = ntohl(ddps.dsh_bytes);
153 dlen = ddps.dsh_len;
154
155 to.sat_addr.s_net = ATADDR_ANYNET;
156 to.sat_addr.s_node = elh->el_dnode;
157 to.sat_port = ddps.dsh_dport;
158 from.sat_addr.s_net = ATADDR_ANYNET;
159 from.sat_addr.s_node = elh->el_snode;
160 from.sat_port = ddps.dsh_sport;
161
162 /*
163 * Make sure that we point to the phase1 ifaddr info and that
164 * it's valid for this packet.
165 */
166 for (aa = at_ifaddr_list; aa != NULL; aa = aa->aa_next) {
167 if ((aa->aa_ifp == ifp)
168 && ((aa->aa_flags & AFA_PHASE2) == 0)
169 && ((to.sat_addr.s_node ==
170 AA_SAT(aa)->sat_addr.s_node) ||
171 (to.sat_addr.s_node == ATADDR_BCAST)))
172 break;
173 }
174 /*
175 * maybe we got a broadcast not meant for us.. ditch it.
176 */
177 if (aa == NULL) {
178 m_freem(m);
179 return;
180 }
181 } else {
182 /*
183 * There was no 'elh' passed on. This could still be either
184 * phase1 or phase2. We have a long header, but we may be
185 * running on a phase 1 net. Extract out all the info
186 * regarding this packet's src & dst.
187 */
188 ddpstat.ddps_long++;
189
190 if (m->m_len < sizeof(struct ddpehdr) &&
191 ((m = m_pullup(m, sizeof(struct ddpehdr))) == NULL)) {
192 ddpstat.ddps_tooshort++;
193 return;
194 }
195
196 deh = mtod(m, struct ddpehdr *);
197 bcopy((caddr_t)deh, (caddr_t)&ddpe, sizeof(struct ddpehdr));
198 ddpe.deh_bytes = ntohl(ddpe.deh_bytes);
199 dlen = ddpe.deh_len;
200
201 if ((cksum = ddpe.deh_sum) == 0)
202 ddpstat.ddps_nosum++;
203
204 from.sat_addr.s_net = ddpe.deh_snet;
205 from.sat_addr.s_node = ddpe.deh_snode;
206 from.sat_port = ddpe.deh_sport;
207 to.sat_addr.s_net = ddpe.deh_dnet;
208 to.sat_addr.s_node = ddpe.deh_dnode;
209 to.sat_port = ddpe.deh_dport;
210
211 if (to.sat_addr.s_net == ATADDR_ANYNET) {
212 /*
213 * The TO address doesn't specify a net, so by
214 * definition it's for this net. Try find ifaddr
215 * info with the right phase, the right interface,
216 * and either to our node, a broadcast, or looped
217 * back (though that SHOULD be covered in the other
218 * cases).
219 *
220 * XXX If we have multiple interfaces, then the first
221 * with this node number will match (which may NOT be
222 * what we want, but it's probably safe in 99.999% of
223 * cases.
224 */
225 for (aa = at_ifaddr_list; aa != NULL;
226 aa = aa->aa_next) {
227 if (phase == 1 && (aa->aa_flags &
228 AFA_PHASE2))
229 continue;
230 if (phase == 2 && (aa->aa_flags &
231 AFA_PHASE2) == 0)
232 continue;
233 if ((aa->aa_ifp == ifp) &&
234 ((to.sat_addr.s_node ==
235 AA_SAT(aa)->sat_addr.s_node) ||
236 (to.sat_addr.s_node == ATADDR_BCAST) ||
237 (ifp->if_flags & IFF_LOOPBACK)))
238 break;
239 }
240 } else {
241 /*
242 * A destination network was given. We just try to
243 * find which ifaddr info matches it.
244 */
245 for (aa = at_ifaddr_list; aa != NULL;
246 aa = aa->aa_next) {
247 /*
248 * This is a kludge. Accept packets that are
249 * for any router on a local netrange.
250 */
251 if (to.sat_addr.s_net == aa->aa_firstnet &&
252 to.sat_addr.s_node == 0)
253 break;
254 /*
255 * Don't use ifaddr info for which we are
256 * totally outside the netrange, and it's not
257 * a startup packet. Startup packets are
258 * always implicitly allowed on to the next
259 * test.
260 */
261 if (((ntohs(to.sat_addr.s_net) <
262 ntohs(aa->aa_firstnet)) ||
263 (ntohs(to.sat_addr.s_net) >
264 ntohs(aa->aa_lastnet))) &&
265 ((ntohs(to.sat_addr.s_net) < 0xff00) ||
266 (ntohs(to.sat_addr.s_net) > 0xfffe)))
267 continue;
268
269 /*
270 * Don't record a match either if we just
271 * don't have a match in the node address.
272 * This can have if the interface is in
273 * promiscuous mode for example.
274 */
275 if ((to.sat_addr.s_node !=
276 AA_SAT(aa)->sat_addr.s_node) &&
277 (to.sat_addr.s_node != ATADDR_BCAST))
278 continue;
279 break;
280 }
281 }
282 }
283
284 /*
285 * Adjust the length, removing any padding that may have been added
286 * at a link layer. We do this before we attempt to forward a
287 * packet, possibly on a different media.
288 */
289 mlen = m->m_pkthdr.len;
290 if (mlen < dlen) {
291 ddpstat.ddps_toosmall++;
292 m_freem(m);
293 return;
294 }
295 if (mlen > dlen)
296 m_adj(m, dlen - mlen);
297
298 /*
299 * If it isn't for a net on any of our interfaces, or it IS for a net
300 * on a different interface than it came in on, (and it is not looped
301 * back) then consider if we should forward it. As we are not really
302 * a router this is a bit cheeky, but it may be useful some day.
303 */
304 if ((aa == NULL) || ((to.sat_addr.s_node == ATADDR_BCAST) &&
305 (aa->aa_ifp != ifp) && ((ifp->if_flags & IFF_LOOPBACK) == 0))) {
306 /*
307 * If we've explicitly disabled it, don't route anything.
308 */
309 if (ddp_forward == 0) {
310 m_freem(m);
311 return;
312 }
313
314 /*
315 * If the cached forwarding route is still valid, use it.
316 *
317 * XXXRW: Access to the cached route may not be properly
318 * synchronized for parallel input handling.
319 */
320 if (forwro.ro_rt &&
321 (satosat(&forwro.ro_dst)->sat_addr.s_net !=
322 to.sat_addr.s_net ||
323 satosat(&forwro.ro_dst)->sat_addr.s_node !=
324 to.sat_addr.s_node)) {
325 RTFREE(forwro.ro_rt);
326 forwro.ro_rt = NULL;
327 }
328
329 /*
330 * If we don't have a cached one (any more) or it's useless,
331 * then get a new route.
332 *
333 * XXX this could cause a 'route leak'. Check this!
334 */
335 if (forwro.ro_rt == NULL || forwro.ro_rt->rt_ifp == NULL) {
336 forwro.ro_dst.sa_len = sizeof(struct sockaddr_at);
337 forwro.ro_dst.sa_family = AF_APPLETALK;
338 satosat(&forwro.ro_dst)->sat_addr.s_net =
339 to.sat_addr.s_net;
340 satosat(&forwro.ro_dst)->sat_addr.s_node =
341 to.sat_addr.s_node;
342 rtalloc(&forwro);
343 }
344
345 /*
346 * If it's not going to get there on this hop, and it's
347 * already done too many hops, then throw it away.
348 */
349 if ((to.sat_addr.s_net !=
350 satosat(&forwro.ro_dst)->sat_addr.s_net) &&
351 (ddpe.deh_hops == DDP_MAXHOPS)) {
352 m_freem(m);
353 return;
354 }
355
356 /*
357 * A ddp router might use the same interface to forward the
358 * packet, which this would not effect. Don't allow packets
359 * to cross from one interface to another however.
360 */
361 if (ddp_firewall && ((forwro.ro_rt == NULL) ||
362 (forwro.ro_rt->rt_ifp != ifp))) {
363 m_freem(m);
364 return;
365 }
366
367 /*
368 * Adjust the header. If it was a short header then it would
369 * have not gotten here, so we can assume there is room to
370 * drop the header in.
371 *
372 * XXX what about promiscuous mode, etc...
373 */
374 ddpe.deh_hops++;
375 ddpe.deh_bytes = htonl(ddpe.deh_bytes);
376 /* XXX deh? */
377 bcopy((caddr_t)&ddpe, (caddr_t)deh, sizeof(u_short));
378 if (ddp_route(m, &forwro))
379 ddpstat.ddps_cantforward++;
380 else
381 ddpstat.ddps_forward++;
382 return;
383 }
384
385 /*
386 * It was for us, and we have an ifaddr to use with it.
387 */
388 from.sat_len = sizeof(struct sockaddr_at);
389 from.sat_family = AF_APPLETALK;
390
391 /*
392 * We are no longer interested in the link layer so cut it off.
393 */
394 if (elh == NULL) {
395 if (ddp_cksum && cksum && cksum !=
396 at_cksum(m, sizeof(int))) {
397 ddpstat.ddps_badsum++;
398 m_freem(m);
399 return;
400 }
401 m_adj(m, sizeof(struct ddpehdr));
402 } else
403 m_adj(m, sizeof(struct ddpshdr));
404
405 /*
406 * Search for ddp protocol control blocks that match these addresses.
407 */
408 DDP_LIST_SLOCK();
409 if ((ddp = ddp_search(&from, &to, aa)) == NULL)
410 goto out;
411
412 #ifdef MAC
413 SOCK_LOCK(ddp->ddp_socket);
414 if (mac_check_socket_deliver(ddp->ddp_socket, m) != 0) {
415 SOCK_UNLOCK(ddp->ddp_socket);
416 goto out;
417 }
418 SOCK_UNLOCK(ddp->ddp_socket);
419 #endif
420
421 /*
422 * If we found one, deliver the packet to the socket
423 */
424 SOCKBUF_LOCK(&ddp->ddp_socket->so_rcv);
425 if (sbappendaddr_locked(&ddp->ddp_socket->so_rcv,
426 (struct sockaddr *)&from, m, NULL) == 0) {
427 SOCKBUF_UNLOCK(&ddp->ddp_socket->so_rcv);
428 /*
429 * If the socket is full (or similar error) dump the packet.
430 */
431 ddpstat.ddps_nosockspace++;
432 goto out;
433 }
434
435 /*
436 * And wake up whatever might be waiting for it
437 */
438 sorwakeup_locked(ddp->ddp_socket);
439 m = NULL;
440 out:
441 DDP_LIST_SUNLOCK();
442 if (m != NULL)
443 m_freem(m);
444 }
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