xref: /freebsd/usr.sbin/iscsid/iscsid.c (revision 6186fd1857626de0f7cb1a9e4dff19082f9ebb11) 
1 /*-
2  * Copyright (c) 2012 The FreeBSD Foundation
3  * All rights reserved.
4  *
5  * This software was developed by Edward Tomasz Napierala under sponsorship
6  * from the FreeBSD Foundation.
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  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  */
30 
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 #include <sys/types.h>
35 #include <sys/time.h>
36 #include <sys/ioctl.h>
37 #include <sys/param.h>
38 #include <sys/linker.h>
39 #include <sys/socket.h>
40 #include <sys/capsicum.h>
41 #include <sys/wait.h>
42 #include <assert.h>
43 #include <errno.h>
44 #include <fcntl.h>
45 #include <netdb.h>
46 #include <signal.h>
47 #include <stdbool.h>
48 #include <stdint.h>
49 #include <stdio.h>
50 #include <stdlib.h>
51 #include <string.h>
52 #include <unistd.h>
53 
54 #include <libutil.h>
55 
56 #include "iscsid.h"
57 
58 static volatile bool sigalrm_received = false;
59 
60 static int nchildren = 0;
61 
62 static void
63 usage(void)
64 {
65 
66 	fprintf(stderr, "usage: iscsid [-P pidfile][-d][-m maxproc][-t timeout]\n");
67 	exit(1);
68 }
69 
70 char *
71 checked_strdup(const char *s)
72 {
73 	char *c;
74 
75 	c = strdup(s);
76 	if (c == NULL)
77 		log_err(1, "strdup");
78 	return (c);
79 }
80 
81 static void
82 resolve_addr(const struct connection *conn, const char *address,
83     struct addrinfo **ai, bool initiator_side)
84 {
85 	struct addrinfo hints;
86 	char *arg, *addr, *ch;
87 	const char *port;
88 	int error, colons = 0;
89 
90 	arg = checked_strdup(address);
91 
92 	if (arg[0] == '\0') {
93 		fail(conn, "empty address");
94 		log_errx(1, "empty address");
95 	}
96 	if (arg[0] == '[') {
97 		/*
98 		 * IPv6 address in square brackets, perhaps with port.
99 		 */
100 		arg++;
101 		addr = strsep(&arg, "]");
102 		if (arg == NULL) {
103 			fail(conn, "malformed address");
104 			log_errx(1, "malformed address %s", address);
105 		}
106 		if (arg[0] == '\0') {
107 			port = NULL;
108 		} else if (arg[0] == ':') {
109 			port = arg + 1;
110 		} else {
111 			fail(conn, "malformed address");
112 			log_errx(1, "malformed address %s", address);
113 		}
114 	} else {
115 		/*
116 		 * Either IPv6 address without brackets - and without
117 		 * a port - or IPv4 address.  Just count the colons.
118 		 */
119 		for (ch = arg; *ch != '\0'; ch++) {
120 			if (*ch == ':')
121 				colons++;
122 		}
123 		if (colons > 1) {
124 			addr = arg;
125 			port = NULL;
126 		} else {
127 			addr = strsep(&arg, ":");
128 			if (arg == NULL)
129 				port = NULL;
130 			else
131 				port = arg;
132 		}
133 	}
134 
135 	if (port == NULL && !initiator_side)
136 		port = "3260";
137 
138 	memset(&hints, 0, sizeof(hints));
139 	hints.ai_family = PF_UNSPEC;
140 	hints.ai_socktype = SOCK_STREAM;
141 	hints.ai_flags = AI_ADDRCONFIG | AI_NUMERICSERV;
142 	if (initiator_side)
143 		hints.ai_flags |= AI_PASSIVE;
144 
145 	error = getaddrinfo(addr, port, &hints, ai);
146 	if (error != 0) {
147 		fail(conn, gai_strerror(error));
148 		log_errx(1, "getaddrinfo for %s failed: %s",
149 		    address, gai_strerror(error));
150 	}
151 }
152 
153 static struct connection *
154 connection_new(unsigned int session_id, const uint8_t isid[8], uint16_t tsih,
155     const struct iscsi_session_conf *conf, int iscsi_fd)
156 {
157 	struct connection *conn;
158 	struct addrinfo *from_ai, *to_ai;
159 	const char *from_addr, *to_addr;
160 #ifdef ICL_KERNEL_PROXY
161 	struct iscsi_daemon_connect idc;
162 #endif
163 	int error;
164 
165 	conn = calloc(1, sizeof(*conn));
166 	if (conn == NULL)
167 		log_err(1, "calloc");
168 
169 	/*
170 	 * Default values, from RFC 3720, section 12.
171 	 */
172 	conn->conn_header_digest = CONN_DIGEST_NONE;
173 	conn->conn_data_digest = CONN_DIGEST_NONE;
174 	conn->conn_initial_r2t = true;
175 	conn->conn_immediate_data = true;
176 	conn->conn_max_data_segment_length = 8192;
177 	conn->conn_max_burst_length = 262144;
178 	conn->conn_first_burst_length = 65536;
179 
180 	conn->conn_session_id = session_id;
181 	memcpy(&conn->conn_isid, isid, sizeof(conn->conn_isid));
182 	conn->conn_tsih = tsih;
183 	conn->conn_iscsi_fd = iscsi_fd;
184 
185 	/*
186 	 * XXX: Should we sanitize this somehow?
187 	 */
188 	memcpy(&conn->conn_conf, conf, sizeof(conn->conn_conf));
189 
190 	from_addr = conn->conn_conf.isc_initiator_addr;
191 	to_addr = conn->conn_conf.isc_target_addr;
192 
193 	if (from_addr[0] != '\0')
194 		resolve_addr(conn, from_addr, &from_ai, true);
195 	else
196 		from_ai = NULL;
197 
198 	resolve_addr(conn, to_addr, &to_ai, false);
199 
200 #ifdef ICL_KERNEL_PROXY
201 	if (conn->conn_conf.isc_iser) {
202 		memset(&idc, 0, sizeof(idc));
203 		idc.idc_session_id = conn->conn_session_id;
204 		if (conn->conn_conf.isc_iser)
205 			idc.idc_iser = 1;
206 		idc.idc_domain = to_ai->ai_family;
207 		idc.idc_socktype = to_ai->ai_socktype;
208 		idc.idc_protocol = to_ai->ai_protocol;
209 		if (from_ai != NULL) {
210 			idc.idc_from_addr = from_ai->ai_addr;
211 			idc.idc_from_addrlen = from_ai->ai_addrlen;
212 		}
213 		idc.idc_to_addr = to_ai->ai_addr;
214 		idc.idc_to_addrlen = to_ai->ai_addrlen;
215 
216 		log_debugx("connecting to %s using ICL kernel proxy", to_addr);
217 		error = ioctl(iscsi_fd, ISCSIDCONNECT, &idc);
218 		if (error != 0) {
219 			fail(conn, strerror(errno));
220 			log_err(1, "failed to connect to %s "
221 			    "using ICL kernel proxy: ISCSIDCONNECT", to_addr);
222 		}
223 
224 		return (conn);
225 	}
226 #endif /* ICL_KERNEL_PROXY */
227 
228 	if (conn->conn_conf.isc_iser) {
229 		fail(conn, "iSER not supported");
230 		log_errx(1, "iscsid(8) compiled without ICL_KERNEL_PROXY "
231 		    "does not support iSER");
232 	}
233 
234 	conn->conn_socket = socket(to_ai->ai_family, to_ai->ai_socktype,
235 	    to_ai->ai_protocol);
236 	if (conn->conn_socket < 0) {
237 		fail(conn, strerror(errno));
238 		log_err(1, "failed to create socket for %s", from_addr);
239 	}
240 	if (from_ai != NULL) {
241 		error = bind(conn->conn_socket, from_ai->ai_addr,
242 		    from_ai->ai_addrlen);
243 		if (error != 0) {
244 			fail(conn, strerror(errno));
245 			log_err(1, "failed to bind to %s", from_addr);
246 		}
247 	}
248 	log_debugx("connecting to %s", to_addr);
249 	error = connect(conn->conn_socket, to_ai->ai_addr, to_ai->ai_addrlen);
250 	if (error != 0) {
251 		fail(conn, strerror(errno));
252 		log_err(1, "failed to connect to %s", to_addr);
253 	}
254 
255 	return (conn);
256 }
257 
258 static void
259 handoff(struct connection *conn)
260 {
261 	struct iscsi_daemon_handoff idh;
262 	int error;
263 
264 	log_debugx("handing off connection to the kernel");
265 
266 	memset(&idh, 0, sizeof(idh));
267 	idh.idh_session_id = conn->conn_session_id;
268 	idh.idh_socket = conn->conn_socket;
269 	strlcpy(idh.idh_target_alias, conn->conn_target_alias,
270 	    sizeof(idh.idh_target_alias));
271 	idh.idh_tsih = conn->conn_tsih;
272 	idh.idh_statsn = conn->conn_statsn;
273 	idh.idh_header_digest = conn->conn_header_digest;
274 	idh.idh_data_digest = conn->conn_data_digest;
275 	idh.idh_initial_r2t = conn->conn_initial_r2t;
276 	idh.idh_immediate_data = conn->conn_immediate_data;
277 	idh.idh_max_data_segment_length = conn->conn_max_data_segment_length;
278 	idh.idh_max_burst_length = conn->conn_max_burst_length;
279 	idh.idh_first_burst_length = conn->conn_first_burst_length;
280 
281 	error = ioctl(conn->conn_iscsi_fd, ISCSIDHANDOFF, &idh);
282 	if (error != 0)
283 		log_err(1, "ISCSIDHANDOFF");
284 }
285 
286 void
287 fail(const struct connection *conn, const char *reason)
288 {
289 	struct iscsi_daemon_fail idf;
290 	int error;
291 
292 	memset(&idf, 0, sizeof(idf));
293 	idf.idf_session_id = conn->conn_session_id;
294 	strlcpy(idf.idf_reason, reason, sizeof(idf.idf_reason));
295 
296 	error = ioctl(conn->conn_iscsi_fd, ISCSIDFAIL, &idf);
297 	if (error != 0)
298 		log_err(1, "ISCSIDFAIL");
299 }
300 
301 /*
302  * XXX: I CANT INTO LATIN
303  */
304 static void
305 capsicate(struct connection *conn)
306 {
307 	int error;
308 	cap_rights_t rights;
309 #ifdef ICL_KERNEL_PROXY
310 	const unsigned long cmds[] = { ISCSIDCONNECT, ISCSIDSEND, ISCSIDRECEIVE,
311 	    ISCSIDHANDOFF, ISCSIDFAIL, ISCSISADD, ISCSISREMOVE, ISCSISMODIFY };
312 #else
313 	const unsigned long cmds[] = { ISCSIDHANDOFF, ISCSIDFAIL, ISCSISADD,
314 	    ISCSISREMOVE, ISCSISMODIFY };
315 #endif
316 
317 	cap_rights_init(&rights, CAP_IOCTL);
318 	error = cap_rights_limit(conn->conn_iscsi_fd, &rights);
319 	if (error != 0 && errno != ENOSYS)
320 		log_err(1, "cap_rights_limit");
321 
322 	error = cap_ioctls_limit(conn->conn_iscsi_fd, cmds,
323 	    sizeof(cmds) / sizeof(cmds[0]));
324 	if (error != 0 && errno != ENOSYS)
325 		log_err(1, "cap_ioctls_limit");
326 
327 	error = cap_enter();
328 	if (error != 0 && errno != ENOSYS)
329 		log_err(1, "cap_enter");
330 
331 	if (cap_sandboxed())
332 		log_debugx("Capsicum capability mode enabled");
333 	else
334 		log_warnx("Capsicum capability mode not supported");
335 }
336 
337 bool
338 timed_out(void)
339 {
340 
341 	return (sigalrm_received);
342 }
343 
344 static void
345 sigalrm_handler(int dummy __unused)
346 {
347 	/*
348 	 * It would be easiest to just log an error and exit.  We can't
349 	 * do this, though, because log_errx() is not signal safe, since
350 	 * it calls syslog(3).  Instead, set a flag checked by pdu_send()
351 	 * and pdu_receive(), to call log_errx() there.  Should they fail
352 	 * to notice, we'll exit here one second later.
353 	 */
354 	if (sigalrm_received) {
355 		/*
356 		 * Oh well.  Just give up and quit.
357 		 */
358 		_exit(2);
359 	}
360 
361 	sigalrm_received = true;
362 }
363 
364 static void
365 set_timeout(int timeout)
366 {
367 	struct sigaction sa;
368 	struct itimerval itv;
369 	int error;
370 
371 	if (timeout <= 0) {
372 		log_debugx("session timeout disabled");
373 		return;
374 	}
375 
376 	bzero(&sa, sizeof(sa));
377 	sa.sa_handler = sigalrm_handler;
378 	sigfillset(&sa.sa_mask);
379 	error = sigaction(SIGALRM, &sa, NULL);
380 	if (error != 0)
381 		log_err(1, "sigaction");
382 
383 	/*
384 	 * First SIGALRM will arive after conf_timeout seconds.
385 	 * If we do nothing, another one will arrive a second later.
386 	 */
387 	bzero(&itv, sizeof(itv));
388 	itv.it_interval.tv_sec = 1;
389 	itv.it_value.tv_sec = timeout;
390 
391 	log_debugx("setting session timeout to %d seconds",
392 	    timeout);
393 	error = setitimer(ITIMER_REAL, &itv, NULL);
394 	if (error != 0)
395 		log_err(1, "setitimer");
396 }
397 
398 static void
399 sigchld_handler(int dummy __unused)
400 {
401 
402 	/*
403 	 * The only purpose of this handler is to make SIGCHLD
404 	 * interrupt the ISCSIDWAIT ioctl(2), so we can call
405 	 * wait_for_children().
406 	 */
407 }
408 
409 static void
410 register_sigchld(void)
411 {
412 	struct sigaction sa;
413 	int error;
414 
415 	bzero(&sa, sizeof(sa));
416 	sa.sa_handler = sigchld_handler;
417 	sigfillset(&sa.sa_mask);
418 	error = sigaction(SIGCHLD, &sa, NULL);
419 	if (error != 0)
420 		log_err(1, "sigaction");
421 
422 }
423 
424 static void
425 handle_request(int iscsi_fd, const struct iscsi_daemon_request *request, int timeout)
426 {
427 	struct connection *conn;
428 
429 	log_set_peer_addr(request->idr_conf.isc_target_addr);
430 	if (request->idr_conf.isc_target[0] != '\0') {
431 		log_set_peer_name(request->idr_conf.isc_target);
432 		setproctitle("%s (%s)", request->idr_conf.isc_target_addr, request->idr_conf.isc_target);
433 	} else {
434 		setproctitle("%s", request->idr_conf.isc_target_addr);
435 	}
436 
437 	conn = connection_new(request->idr_session_id, request->idr_isid,
438 	    request->idr_tsih, &request->idr_conf, iscsi_fd);
439 	set_timeout(timeout);
440 	capsicate(conn);
441 	login(conn);
442 	if (conn->conn_conf.isc_discovery != 0)
443 		discovery(conn);
444 	else
445 		handoff(conn);
446 
447 	log_debugx("nothing more to do; exiting");
448 	exit (0);
449 }
450 
451 static int
452 wait_for_children(bool block)
453 {
454 	pid_t pid;
455 	int status;
456 	int num = 0;
457 
458 	for (;;) {
459 		/*
460 		 * If "block" is true, wait for at least one process.
461 		 */
462 		if (block && num == 0)
463 			pid = wait4(-1, &status, 0, NULL);
464 		else
465 			pid = wait4(-1, &status, WNOHANG, NULL);
466 		if (pid <= 0)
467 			break;
468 		if (WIFSIGNALED(status)) {
469 			log_warnx("child process %d terminated with signal %d",
470 			    pid, WTERMSIG(status));
471 		} else if (WEXITSTATUS(status) != 0) {
472 			log_warnx("child process %d terminated with exit status %d",
473 			    pid, WEXITSTATUS(status));
474 		} else {
475 			log_debugx("child process %d terminated gracefully", pid);
476 		}
477 		num++;
478 	}
479 
480 	return (num);
481 }
482 
483 int
484 main(int argc, char **argv)
485 {
486 	int ch, debug = 0, error, iscsi_fd, maxproc = 30, retval, saved_errno,
487 	    timeout = 60;
488 	bool dont_daemonize = false;
489 	struct pidfh *pidfh;
490 	pid_t pid, otherpid;
491 	const char *pidfile_path = DEFAULT_PIDFILE;
492 	struct iscsi_daemon_request request;
493 
494 	while ((ch = getopt(argc, argv, "P:dl:m:t:")) != -1) {
495 		switch (ch) {
496 		case 'P':
497 			pidfile_path = optarg;
498 			break;
499 		case 'd':
500 			dont_daemonize = true;
501 			debug++;
502 			break;
503 		case 'l':
504 			debug = atoi(optarg);
505 			break;
506 		case 'm':
507 			maxproc = atoi(optarg);
508 			break;
509 		case 't':
510 			timeout = atoi(optarg);
511 			break;
512 		case '?':
513 		default:
514 			usage();
515 		}
516 	}
517 	argc -= optind;
518 	if (argc != 0)
519 		usage();
520 
521 	log_init(debug);
522 
523 	pidfh = pidfile_open(pidfile_path, 0600, &otherpid);
524 	if (pidfh == NULL) {
525 		if (errno == EEXIST)
526 			log_errx(1, "daemon already running, pid: %jd.",
527 			    (intmax_t)otherpid);
528 		log_err(1, "cannot open or create pidfile \"%s\"",
529 		    pidfile_path);
530 	}
531 
532 	iscsi_fd = open(ISCSI_PATH, O_RDWR);
533 	if (iscsi_fd < 0 && errno == ENOENT) {
534 		saved_errno = errno;
535 		retval = kldload("iscsi");
536 		if (retval != -1)
537 			iscsi_fd = open(ISCSI_PATH, O_RDWR);
538 		else
539 			errno = saved_errno;
540 	}
541 	if (iscsi_fd < 0)
542 		log_err(1, "failed to open %s", ISCSI_PATH);
543 
544 	if (dont_daemonize == false) {
545 		if (daemon(0, 0) == -1) {
546 			log_warn("cannot daemonize");
547 			pidfile_remove(pidfh);
548 			exit(1);
549 		}
550 	}
551 
552 	pidfile_write(pidfh);
553 
554 	register_sigchld();
555 
556 	for (;;) {
557 		log_debugx("waiting for request from the kernel");
558 
559 		memset(&request, 0, sizeof(request));
560 		error = ioctl(iscsi_fd, ISCSIDWAIT, &request);
561 		if (error != 0) {
562 			if (errno == EINTR) {
563 				nchildren -= wait_for_children(false);
564 				assert(nchildren >= 0);
565 				continue;
566 			}
567 
568 			log_err(1, "ISCSIDWAIT");
569 		}
570 
571 		if (dont_daemonize) {
572 			log_debugx("not forking due to -d flag; "
573 			    "will exit after servicing a single request");
574 		} else {
575 			nchildren -= wait_for_children(false);
576 			assert(nchildren >= 0);
577 
578 			while (maxproc > 0 && nchildren >= maxproc) {
579 				log_debugx("maxproc limit of %d child processes hit; "
580 				    "waiting for child process to exit", maxproc);
581 				nchildren -= wait_for_children(true);
582 				assert(nchildren >= 0);
583 			}
584 			log_debugx("incoming connection; forking child process #%d",
585 			    nchildren);
586 			nchildren++;
587 
588 			pid = fork();
589 			if (pid < 0)
590 				log_err(1, "fork");
591 			if (pid > 0)
592 				continue;
593 		}
594 
595 		pidfile_close(pidfh);
596 		handle_request(iscsi_fd, &request, timeout);
597 	}
598 
599 	return (0);
600 }
601