1 /*-
2 * server.c
3 *
4 * SPDX-License-Identifier: BSD-2-Clause
5 *
6 * Copyright (c) 2004 Maksim Yevmenkin <m_evmenkin@yahoo.com>
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 *
30 * $Id: server.c,v 1.6 2004/01/13 01:54:39 max Exp $
31 */
32
33 #include <sys/param.h>
34 #include <sys/select.h>
35 #include <sys/stat.h>
36 #include <sys/queue.h>
37 #include <sys/ucred.h>
38 #include <sys/un.h>
39 #include <netinet/in.h>
40 #include <arpa/inet.h>
41 #include <assert.h>
42 #define L2CAP_SOCKET_CHECKED
43 #include <bluetooth.h>
44 #include <errno.h>
45 #include <pwd.h>
46 #include <sdp.h>
47 #include <stdio.h>
48 #include <stdlib.h>
49 #include <string.h>
50 #include <unistd.h>
51 #include "log.h"
52 #include "profile.h"
53 #include "provider.h"
54 #include "server.h"
55
56 static void server_accept_client (server_p srv, int32_t fd);
57 static int32_t server_process_request (server_p srv, int32_t fd);
58 static int32_t server_send_error_response (server_p srv, int32_t fd,
59 uint16_t error);
60 static void server_close_fd (server_p srv, int32_t fd);
61
62 /*
63 * Initialize server
64 */
65
66 int32_t
server_init(server_p srv,char const * control)67 server_init(server_p srv, char const *control)
68 {
69 struct sockaddr_un un;
70 struct sockaddr_l2cap l2;
71 int32_t unsock, l2sock;
72 socklen_t size;
73 uint16_t imtu;
74
75 assert(srv != NULL);
76 assert(control != NULL);
77
78 memset(srv, 0, sizeof(*srv));
79
80 /* Open control socket */
81 if (unlink(control) < 0 && errno != ENOENT) {
82 log_crit("Could not unlink(%s). %s (%d)",
83 control, strerror(errno), errno);
84 return (-1);
85 }
86
87 unsock = socket(PF_LOCAL, SOCK_STREAM, 0);
88 if (unsock < 0) {
89 log_crit("Could not create control socket. %s (%d)",
90 strerror(errno), errno);
91 return (-1);
92 }
93
94 memset(&un, 0, sizeof(un));
95 un.sun_len = sizeof(un);
96 un.sun_family = AF_LOCAL;
97 strlcpy(un.sun_path, control, sizeof(un.sun_path));
98
99 if (bind(unsock, (struct sockaddr *) &un, sizeof(un)) < 0) {
100 log_crit("Could not bind control socket. %s (%d)",
101 strerror(errno), errno);
102 close(unsock);
103 return (-1);
104 }
105
106 if (chmod(control, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH) < 0) {
107 log_crit("Could not change permissions on control socket. " \
108 "%s (%d)", strerror(errno), errno);
109 close(unsock);
110 return (-1);
111 }
112
113 if (listen(unsock, 10) < 0) {
114 log_crit("Could not listen on control socket. %s (%d)",
115 strerror(errno), errno);
116 close(unsock);
117 return (-1);
118 }
119
120 /* Open L2CAP socket */
121 l2sock = socket(PF_BLUETOOTH, SOCK_SEQPACKET, BLUETOOTH_PROTO_L2CAP);
122 if (l2sock < 0) {
123 log_crit("Could not create L2CAP socket. %s (%d)",
124 strerror(errno), errno);
125 close(unsock);
126 return (-1);
127 }
128
129 size = sizeof(imtu);
130 if (getsockopt(l2sock, SOL_L2CAP, SO_L2CAP_IMTU, &imtu, &size) < 0) {
131 log_crit("Could not get L2CAP IMTU. %s (%d)",
132 strerror(errno), errno);
133 close(unsock);
134 close(l2sock);
135 return (-1);
136 }
137
138 memset(&l2, 0, sizeof(l2));
139 l2.l2cap_len = sizeof(l2);
140 l2.l2cap_family = AF_BLUETOOTH;
141 memcpy(&l2.l2cap_bdaddr, NG_HCI_BDADDR_ANY, sizeof(l2.l2cap_bdaddr));
142 l2.l2cap_psm = htole16(NG_L2CAP_PSM_SDP);
143
144 if (bind(l2sock, (struct sockaddr *) &l2, sizeof(l2)) < 0) {
145 log_crit("Could not bind L2CAP socket. %s (%d)",
146 strerror(errno), errno);
147 close(unsock);
148 close(l2sock);
149 return (-1);
150 }
151
152 if (listen(l2sock, 10) < 0) {
153 log_crit("Could not listen on L2CAP socket. %s (%d)",
154 strerror(errno), errno);
155 close(unsock);
156 close(l2sock);
157 return (-1);
158 }
159
160 /* Allocate incoming buffer */
161 srv->imtu = (imtu > SDP_LOCAL_MTU)? imtu : SDP_LOCAL_MTU;
162 srv->req = (uint8_t *) calloc(srv->imtu, sizeof(srv->req[0]));
163 if (srv->req == NULL) {
164 log_crit("Could not allocate request buffer");
165 close(unsock);
166 close(l2sock);
167 return (-1);
168 }
169
170 /* Allocate memory for descriptor index */
171 srv->fdidx = (fd_idx_p) calloc(FD_SETSIZE, sizeof(srv->fdidx[0]));
172 if (srv->fdidx == NULL) {
173 log_crit("Could not allocate fd index");
174 free(srv->req);
175 close(unsock);
176 close(l2sock);
177 return (-1);
178 }
179
180 /* Register Service Discovery profile (attach it to control socket) */
181 if (provider_register_sd(unsock) < 0) {
182 log_crit("Could not register Service Discovery profile");
183 free(srv->fdidx);
184 free(srv->req);
185 close(unsock);
186 close(l2sock);
187 return (-1);
188 }
189
190 /*
191 * If we got here then everything is fine. Add both control sockets
192 * to the index.
193 */
194
195 FD_ZERO(&srv->fdset);
196 srv->maxfd = (unsock > l2sock)? unsock : l2sock;
197
198 FD_SET(unsock, &srv->fdset);
199 srv->fdidx[unsock].valid = 1;
200 srv->fdidx[unsock].server = 1;
201 srv->fdidx[unsock].control = 1;
202 srv->fdidx[unsock].priv = 0;
203 srv->fdidx[unsock].rsp_cs = 0;
204 srv->fdidx[unsock].rsp_size = 0;
205 srv->fdidx[unsock].rsp_limit = 0;
206 srv->fdidx[unsock].omtu = SDP_LOCAL_MTU;
207 srv->fdidx[unsock].rsp = NULL;
208
209 FD_SET(l2sock, &srv->fdset);
210 srv->fdidx[l2sock].valid = 1;
211 srv->fdidx[l2sock].server = 1;
212 srv->fdidx[l2sock].control = 0;
213 srv->fdidx[l2sock].priv = 0;
214 srv->fdidx[l2sock].rsp_cs = 0;
215 srv->fdidx[l2sock].rsp_size = 0;
216 srv->fdidx[l2sock].rsp_limit = 0;
217 srv->fdidx[l2sock].omtu = 0; /* unknown */
218 srv->fdidx[l2sock].rsp = NULL;
219
220 return (0);
221 }
222
223 /*
224 * Shutdown server
225 */
226
227 void
server_shutdown(server_p srv)228 server_shutdown(server_p srv)
229 {
230 int fd;
231
232 assert(srv != NULL);
233
234 for (fd = 0; fd < srv->maxfd + 1; fd ++)
235 if (srv->fdidx[fd].valid)
236 server_close_fd(srv, fd);
237
238 free(srv->req);
239 free(srv->fdidx);
240
241 memset(srv, 0, sizeof(*srv));
242 }
243
244 /*
245 * Do one server iteration
246 */
247
248 int32_t
server_do(server_p srv)249 server_do(server_p srv)
250 {
251 fd_set fdset;
252 int32_t n, fd;
253
254 assert(srv != NULL);
255
256 /* Copy cached version of the fd set and call select */
257 memcpy(&fdset, &srv->fdset, sizeof(fdset));
258 n = select(srv->maxfd + 1, &fdset, NULL, NULL, NULL);
259 if (n < 0) {
260 if (errno == EINTR)
261 return (0);
262
263 log_err("Could not select(%d, %p). %s (%d)",
264 srv->maxfd + 1, &fdset, strerror(errno), errno);
265
266 return (-1);
267 }
268
269 /* Process descriptors */
270 for (fd = 0; fd < srv->maxfd + 1 && n > 0; fd ++) {
271 if (!FD_ISSET(fd, &fdset))
272 continue;
273
274 assert(srv->fdidx[fd].valid);
275 n --;
276
277 if (srv->fdidx[fd].server)
278 server_accept_client(srv, fd);
279 else if (server_process_request(srv, fd) != 0)
280 server_close_fd(srv, fd);
281 }
282
283 return (0);
284
285 }
286
287 /*
288 * Accept new client connection and register it with index
289 */
290
291 static void
server_accept_client(server_p srv,int32_t fd)292 server_accept_client(server_p srv, int32_t fd)
293 {
294 uint8_t *rsp = NULL;
295 int32_t cfd, priv;
296 uint16_t omtu;
297 socklen_t size;
298
299 do {
300 cfd = accept(fd, NULL, NULL);
301 } while (cfd < 0 && errno == EINTR);
302
303 if (cfd < 0) {
304 log_err("Could not accept connection on %s socket. %s (%d)",
305 srv->fdidx[fd].control? "control" : "L2CAP",
306 strerror(errno), errno);
307 return;
308 }
309
310 assert(!FD_ISSET(cfd, &srv->fdset));
311 assert(!srv->fdidx[cfd].valid);
312
313 priv = 0;
314
315 if (!srv->fdidx[fd].control) {
316 /* Get local BD_ADDR */
317 size = sizeof(srv->req_sa);
318 if (getsockname(cfd,(struct sockaddr*)&srv->req_sa,&size) < 0) {
319 log_err("Could not get local BD_ADDR. %s (%d)",
320 strerror(errno), errno);
321 close(cfd);
322 return;
323 }
324
325 /* Get outgoing MTU */
326 size = sizeof(omtu);
327 if (getsockopt(cfd,SOL_L2CAP,SO_L2CAP_OMTU,&omtu,&size) < 0) {
328 log_err("Could not get L2CAP OMTU. %s (%d)",
329 strerror(errno), errno);
330 close(cfd);
331 return;
332 }
333
334 /*
335 * The maximum size of the L2CAP packet is 65536 bytes.
336 * The minimum L2CAP MTU is 43 bytes. That means we need
337 * 65536 / 43 = ~1524 chunks to transfer maximum packet
338 * size with minimum MTU. The "rsp_cs" field in fd_idx_t
339 * is 11 bits wide, which gives us up to 2048 chunks.
340 */
341
342 if (omtu < NG_L2CAP_MTU_MINIMUM) {
343 log_err("L2CAP OMTU is too small (%d bytes)", omtu);
344 close(cfd);
345 return;
346 }
347 } else {
348 uid_t uid;
349 gid_t gid;
350 struct passwd *pw;
351
352 /* Get peer's credentials */
353 if (getpeereid(cfd, &uid, &gid) < 0) {
354 log_err("Could not get peer's credentials. %s (%d)",
355 strerror(errno), errno);
356 close(cfd);
357 return;
358 }
359
360 /* Check credentials */
361 pw = getpwuid(uid);
362 if (pw != NULL)
363 priv = (strcmp(pw->pw_name, "root") == 0);
364 else
365 log_warning("Could not verify credentials for uid %d",
366 uid);
367
368 memcpy(&srv->req_sa.l2cap_bdaddr, NG_HCI_BDADDR_ANY,
369 sizeof(srv->req_sa.l2cap_bdaddr));
370
371 omtu = srv->fdidx[fd].omtu;
372 }
373
374 /*
375 * Allocate buffer. This is an overkill, but we can not know how
376 * big our reply is going to be.
377 */
378
379 rsp = (uint8_t *) calloc(NG_L2CAP_MTU_MAXIMUM, sizeof(rsp[0]));
380 if (rsp == NULL) {
381 log_crit("Could not allocate response buffer");
382 close(cfd);
383 return;
384 }
385
386 /* Add client descriptor to the index */
387 FD_SET(cfd, &srv->fdset);
388 if (srv->maxfd < cfd)
389 srv->maxfd = cfd;
390 srv->fdidx[cfd].valid = 1;
391 srv->fdidx[cfd].server = 0;
392 srv->fdidx[cfd].control = srv->fdidx[fd].control;
393 srv->fdidx[cfd].priv = priv;
394 srv->fdidx[cfd].rsp_cs = 0;
395 srv->fdidx[cfd].rsp_size = 0;
396 srv->fdidx[cfd].rsp_limit = 0;
397 srv->fdidx[cfd].omtu = omtu;
398 srv->fdidx[cfd].rsp = rsp;
399 }
400
401 /*
402 * Process request from the client
403 */
404
405 static int32_t
server_process_request(server_p srv,int32_t fd)406 server_process_request(server_p srv, int32_t fd)
407 {
408 sdp_pdu_p pdu = (sdp_pdu_p) srv->req;
409 int32_t len, error;
410
411 assert(srv->imtu > 0);
412 assert(srv->req != NULL);
413 assert(FD_ISSET(fd, &srv->fdset));
414 assert(srv->fdidx[fd].valid);
415 assert(!srv->fdidx[fd].server);
416 assert(srv->fdidx[fd].rsp != NULL);
417 assert(srv->fdidx[fd].omtu >= NG_L2CAP_MTU_MINIMUM);
418
419 do {
420 len = read(fd, srv->req, srv->imtu);
421 } while (len < 0 && errno == EINTR);
422
423 if (len < 0) {
424 log_err("Could not receive SDP request from %s socket. %s (%d)",
425 srv->fdidx[fd].control? "control" : "L2CAP",
426 strerror(errno), errno);
427 return (-1);
428 }
429 if (len == 0) {
430 log_info("Client on %s socket has disconnected",
431 srv->fdidx[fd].control? "control" : "L2CAP");
432 return (-1);
433 }
434
435 if (len >= sizeof(*pdu) &&
436 sizeof(*pdu) + (pdu->len = ntohs(pdu->len)) == len) {
437 switch (pdu->pid) {
438 case SDP_PDU_SERVICE_SEARCH_REQUEST:
439 error = server_prepare_service_search_response(srv, fd);
440 break;
441
442 case SDP_PDU_SERVICE_ATTRIBUTE_REQUEST:
443 error = server_prepare_service_attribute_response(srv, fd);
444 break;
445
446 case SDP_PDU_SERVICE_SEARCH_ATTRIBUTE_REQUEST:
447 error = server_prepare_service_search_attribute_response(srv, fd);
448 break;
449
450 case SDP_PDU_SERVICE_REGISTER_REQUEST:
451 error = server_prepare_service_register_response(srv, fd);
452 break;
453
454 case SDP_PDU_SERVICE_UNREGISTER_REQUEST:
455 error = server_prepare_service_unregister_response(srv, fd);
456 break;
457
458 case SDP_PDU_SERVICE_CHANGE_REQUEST:
459 error = server_prepare_service_change_response(srv, fd);
460 break;
461
462 default:
463 error = SDP_ERROR_CODE_INVALID_REQUEST_SYNTAX;
464 break;
465 }
466 } else
467 error = SDP_ERROR_CODE_INVALID_PDU_SIZE;
468
469 if (error == 0) {
470 switch (pdu->pid) {
471 case SDP_PDU_SERVICE_SEARCH_REQUEST:
472 error = server_send_service_search_response(srv, fd);
473 break;
474
475 case SDP_PDU_SERVICE_ATTRIBUTE_REQUEST:
476 error = server_send_service_attribute_response(srv, fd);
477 break;
478
479 case SDP_PDU_SERVICE_SEARCH_ATTRIBUTE_REQUEST:
480 error = server_send_service_search_attribute_response(srv, fd);
481 break;
482
483 case SDP_PDU_SERVICE_REGISTER_REQUEST:
484 error = server_send_service_register_response(srv, fd);
485 break;
486
487 case SDP_PDU_SERVICE_UNREGISTER_REQUEST:
488 error = server_send_service_unregister_response(srv, fd);
489 break;
490
491 case SDP_PDU_SERVICE_CHANGE_REQUEST:
492 error = server_send_service_change_response(srv, fd);
493 break;
494
495 default:
496 error = SDP_ERROR_CODE_INVALID_REQUEST_SYNTAX;
497 break;
498 }
499
500 if (error != 0)
501 log_err("Could not send SDP response to %s socket, " \
502 "pdu->pid=%d, pdu->tid=%d, error=%d",
503 srv->fdidx[fd].control? "control" : "L2CAP",
504 pdu->pid, ntohs(pdu->tid), error);
505 } else {
506 log_err("Could not process SDP request from %s socket, " \
507 "pdu->pid=%d, pdu->tid=%d, pdu->len=%d, len=%d, " \
508 "error=%d",
509 srv->fdidx[fd].control? "control" : "L2CAP",
510 pdu->pid, ntohs(pdu->tid), pdu->len, len, error);
511
512 error = server_send_error_response(srv, fd, error);
513 if (error != 0)
514 log_err("Could not send SDP error response to %s " \
515 "socket, pdu->pid=%d, pdu->tid=%d, error=%d",
516 srv->fdidx[fd].control? "control" : "L2CAP",
517 pdu->pid, ntohs(pdu->tid), error);
518 }
519
520 /* On error forget response (if any) */
521 if (error != 0) {
522 srv->fdidx[fd].rsp_cs = 0;
523 srv->fdidx[fd].rsp_size = 0;
524 srv->fdidx[fd].rsp_limit = 0;
525 }
526
527 return (error);
528 }
529
530 /*
531 * Send SDP_Error_Response PDU
532 */
533
534 static int32_t
server_send_error_response(server_p srv,int32_t fd,uint16_t error)535 server_send_error_response(server_p srv, int32_t fd, uint16_t error)
536 {
537 int32_t size;
538
539 struct {
540 sdp_pdu_t pdu;
541 uint16_t error;
542 } __attribute__ ((packed)) rsp;
543
544 /* Prepare and send SDP error response */
545 rsp.pdu.pid = SDP_PDU_ERROR_RESPONSE;
546 rsp.pdu.tid = ((sdp_pdu_p)(srv->req))->tid;
547 rsp.pdu.len = htons(sizeof(rsp.error));
548 rsp.error = htons(error);
549
550 do {
551 size = write(fd, &rsp, sizeof(rsp));
552 } while (size < 0 && errno == EINTR);
553
554 return ((size < 0)? errno : 0);
555 }
556
557 /*
558 * Close descriptor and remove it from index
559 */
560
561 static void
server_close_fd(server_p srv,int32_t fd)562 server_close_fd(server_p srv, int32_t fd)
563 {
564 provider_p provider = NULL, provider_next = NULL;
565
566 assert(FD_ISSET(fd, &srv->fdset));
567 assert(srv->fdidx[fd].valid);
568
569 close(fd);
570
571 FD_CLR(fd, &srv->fdset);
572 if (fd == srv->maxfd)
573 srv->maxfd --;
574
575 if (srv->fdidx[fd].rsp != NULL)
576 free(srv->fdidx[fd].rsp);
577
578 memset(&srv->fdidx[fd], 0, sizeof(srv->fdidx[fd]));
579
580 for (provider = provider_get_first();
581 provider != NULL;
582 provider = provider_next) {
583 provider_next = provider_get_next(provider);
584
585 if (provider->fd == fd)
586 provider_unregister(provider);
587 }
588 }
589
590