xref: /freebsd/usr.sbin/iscsid/iscsid.c (revision 545ddfbe7d4fe8adfb862903b24eac1d5896c1ef) 
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, sockbuf;
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 	sockbuf = SOCKBUF_SIZE;
241 	if (setsockopt(conn->conn_socket, SOL_SOCKET, SO_RCVBUF,
242 	    &sockbuf, sizeof(sockbuf)) == -1)
243 		log_warn("setsockopt(SO_RCVBUF) failed");
244 	sockbuf = SOCKBUF_SIZE;
245 	if (setsockopt(conn->conn_socket, SOL_SOCKET, SO_SNDBUF,
246 	    &sockbuf, sizeof(sockbuf)) == -1)
247 		log_warn("setsockopt(SO_SNDBUF) failed");
248 	if (from_ai != NULL) {
249 		error = bind(conn->conn_socket, from_ai->ai_addr,
250 		    from_ai->ai_addrlen);
251 		if (error != 0) {
252 			fail(conn, strerror(errno));
253 			log_err(1, "failed to bind to %s", from_addr);
254 		}
255 	}
256 	log_debugx("connecting to %s", to_addr);
257 	error = connect(conn->conn_socket, to_ai->ai_addr, to_ai->ai_addrlen);
258 	if (error != 0) {
259 		fail(conn, strerror(errno));
260 		log_err(1, "failed to connect to %s", to_addr);
261 	}
262 
263 	return (conn);
264 }
265 
266 static void
267 handoff(struct connection *conn)
268 {
269 	struct iscsi_daemon_handoff idh;
270 	int error;
271 
272 	log_debugx("handing off connection to the kernel");
273 
274 	memset(&idh, 0, sizeof(idh));
275 	idh.idh_session_id = conn->conn_session_id;
276 	idh.idh_socket = conn->conn_socket;
277 	strlcpy(idh.idh_target_alias, conn->conn_target_alias,
278 	    sizeof(idh.idh_target_alias));
279 	idh.idh_tsih = conn->conn_tsih;
280 	idh.idh_statsn = conn->conn_statsn;
281 	idh.idh_header_digest = conn->conn_header_digest;
282 	idh.idh_data_digest = conn->conn_data_digest;
283 	idh.idh_initial_r2t = conn->conn_initial_r2t;
284 	idh.idh_immediate_data = conn->conn_immediate_data;
285 	idh.idh_max_data_segment_length = conn->conn_max_data_segment_length;
286 	idh.idh_max_burst_length = conn->conn_max_burst_length;
287 	idh.idh_first_burst_length = conn->conn_first_burst_length;
288 
289 	error = ioctl(conn->conn_iscsi_fd, ISCSIDHANDOFF, &idh);
290 	if (error != 0)
291 		log_err(1, "ISCSIDHANDOFF");
292 }
293 
294 void
295 fail(const struct connection *conn, const char *reason)
296 {
297 	struct iscsi_daemon_fail idf;
298 	int error;
299 
300 	memset(&idf, 0, sizeof(idf));
301 	idf.idf_session_id = conn->conn_session_id;
302 	strlcpy(idf.idf_reason, reason, sizeof(idf.idf_reason));
303 
304 	error = ioctl(conn->conn_iscsi_fd, ISCSIDFAIL, &idf);
305 	if (error != 0)
306 		log_err(1, "ISCSIDFAIL");
307 }
308 
309 /*
310  * XXX: I CANT INTO LATIN
311  */
312 static void
313 capsicate(struct connection *conn)
314 {
315 	int error;
316 	cap_rights_t rights;
317 #ifdef ICL_KERNEL_PROXY
318 	const unsigned long cmds[] = { ISCSIDCONNECT, ISCSIDSEND, ISCSIDRECEIVE,
319 	    ISCSIDHANDOFF, ISCSIDFAIL, ISCSISADD, ISCSISREMOVE, ISCSISMODIFY };
320 #else
321 	const unsigned long cmds[] = { ISCSIDHANDOFF, ISCSIDFAIL, ISCSISADD,
322 	    ISCSISREMOVE, ISCSISMODIFY };
323 #endif
324 
325 	cap_rights_init(&rights, CAP_IOCTL);
326 	error = cap_rights_limit(conn->conn_iscsi_fd, &rights);
327 	if (error != 0 && errno != ENOSYS)
328 		log_err(1, "cap_rights_limit");
329 
330 	error = cap_ioctls_limit(conn->conn_iscsi_fd, cmds,
331 	    sizeof(cmds) / sizeof(cmds[0]));
332 	if (error != 0 && errno != ENOSYS)
333 		log_err(1, "cap_ioctls_limit");
334 
335 	error = cap_enter();
336 	if (error != 0 && errno != ENOSYS)
337 		log_err(1, "cap_enter");
338 
339 	if (cap_sandboxed())
340 		log_debugx("Capsicum capability mode enabled");
341 	else
342 		log_warnx("Capsicum capability mode not supported");
343 }
344 
345 bool
346 timed_out(void)
347 {
348 
349 	return (sigalrm_received);
350 }
351 
352 static void
353 sigalrm_handler(int dummy __unused)
354 {
355 	/*
356 	 * It would be easiest to just log an error and exit.  We can't
357 	 * do this, though, because log_errx() is not signal safe, since
358 	 * it calls syslog(3).  Instead, set a flag checked by pdu_send()
359 	 * and pdu_receive(), to call log_errx() there.  Should they fail
360 	 * to notice, we'll exit here one second later.
361 	 */
362 	if (sigalrm_received) {
363 		/*
364 		 * Oh well.  Just give up and quit.
365 		 */
366 		_exit(2);
367 	}
368 
369 	sigalrm_received = true;
370 }
371 
372 static void
373 set_timeout(int timeout)
374 {
375 	struct sigaction sa;
376 	struct itimerval itv;
377 	int error;
378 
379 	if (timeout <= 0) {
380 		log_debugx("session timeout disabled");
381 		return;
382 	}
383 
384 	bzero(&sa, sizeof(sa));
385 	sa.sa_handler = sigalrm_handler;
386 	sigfillset(&sa.sa_mask);
387 	error = sigaction(SIGALRM, &sa, NULL);
388 	if (error != 0)
389 		log_err(1, "sigaction");
390 
391 	/*
392 	 * First SIGALRM will arive after conf_timeout seconds.
393 	 * If we do nothing, another one will arrive a second later.
394 	 */
395 	bzero(&itv, sizeof(itv));
396 	itv.it_interval.tv_sec = 1;
397 	itv.it_value.tv_sec = timeout;
398 
399 	log_debugx("setting session timeout to %d seconds",
400 	    timeout);
401 	error = setitimer(ITIMER_REAL, &itv, NULL);
402 	if (error != 0)
403 		log_err(1, "setitimer");
404 }
405 
406 static void
407 sigchld_handler(int dummy __unused)
408 {
409 
410 	/*
411 	 * The only purpose of this handler is to make SIGCHLD
412 	 * interrupt the ISCSIDWAIT ioctl(2), so we can call
413 	 * wait_for_children().
414 	 */
415 }
416 
417 static void
418 register_sigchld(void)
419 {
420 	struct sigaction sa;
421 	int error;
422 
423 	bzero(&sa, sizeof(sa));
424 	sa.sa_handler = sigchld_handler;
425 	sigfillset(&sa.sa_mask);
426 	error = sigaction(SIGCHLD, &sa, NULL);
427 	if (error != 0)
428 		log_err(1, "sigaction");
429 
430 }
431 
432 static void
433 handle_request(int iscsi_fd, const struct iscsi_daemon_request *request, int timeout)
434 {
435 	struct connection *conn;
436 
437 	log_set_peer_addr(request->idr_conf.isc_target_addr);
438 	if (request->idr_conf.isc_target[0] != '\0') {
439 		log_set_peer_name(request->idr_conf.isc_target);
440 		setproctitle("%s (%s)", request->idr_conf.isc_target_addr, request->idr_conf.isc_target);
441 	} else {
442 		setproctitle("%s", request->idr_conf.isc_target_addr);
443 	}
444 
445 	conn = connection_new(request->idr_session_id, request->idr_isid,
446 	    request->idr_tsih, &request->idr_conf, iscsi_fd);
447 	set_timeout(timeout);
448 	capsicate(conn);
449 	login(conn);
450 	if (conn->conn_conf.isc_discovery != 0)
451 		discovery(conn);
452 	else
453 		handoff(conn);
454 
455 	log_debugx("nothing more to do; exiting");
456 	exit (0);
457 }
458 
459 static int
460 wait_for_children(bool block)
461 {
462 	pid_t pid;
463 	int status;
464 	int num = 0;
465 
466 	for (;;) {
467 		/*
468 		 * If "block" is true, wait for at least one process.
469 		 */
470 		if (block && num == 0)
471 			pid = wait4(-1, &status, 0, NULL);
472 		else
473 			pid = wait4(-1, &status, WNOHANG, NULL);
474 		if (pid <= 0)
475 			break;
476 		if (WIFSIGNALED(status)) {
477 			log_warnx("child process %d terminated with signal %d",
478 			    pid, WTERMSIG(status));
479 		} else if (WEXITSTATUS(status) != 0) {
480 			log_warnx("child process %d terminated with exit status %d",
481 			    pid, WEXITSTATUS(status));
482 		} else {
483 			log_debugx("child process %d terminated gracefully", pid);
484 		}
485 		num++;
486 	}
487 
488 	return (num);
489 }
490 
491 int
492 main(int argc, char **argv)
493 {
494 	int ch, debug = 0, error, iscsi_fd, maxproc = 30, retval, saved_errno,
495 	    timeout = 60;
496 	bool dont_daemonize = false;
497 	struct pidfh *pidfh;
498 	pid_t pid, otherpid;
499 	const char *pidfile_path = DEFAULT_PIDFILE;
500 	struct iscsi_daemon_request request;
501 
502 	while ((ch = getopt(argc, argv, "P:dl:m:t:")) != -1) {
503 		switch (ch) {
504 		case 'P':
505 			pidfile_path = optarg;
506 			break;
507 		case 'd':
508 			dont_daemonize = true;
509 			debug++;
510 			break;
511 		case 'l':
512 			debug = atoi(optarg);
513 			break;
514 		case 'm':
515 			maxproc = atoi(optarg);
516 			break;
517 		case 't':
518 			timeout = atoi(optarg);
519 			break;
520 		case '?':
521 		default:
522 			usage();
523 		}
524 	}
525 	argc -= optind;
526 	if (argc != 0)
527 		usage();
528 
529 	log_init(debug);
530 
531 	pidfh = pidfile_open(pidfile_path, 0600, &otherpid);
532 	if (pidfh == NULL) {
533 		if (errno == EEXIST)
534 			log_errx(1, "daemon already running, pid: %jd.",
535 			    (intmax_t)otherpid);
536 		log_err(1, "cannot open or create pidfile \"%s\"",
537 		    pidfile_path);
538 	}
539 
540 	iscsi_fd = open(ISCSI_PATH, O_RDWR);
541 	if (iscsi_fd < 0 && errno == ENOENT) {
542 		saved_errno = errno;
543 		retval = kldload("iscsi");
544 		if (retval != -1)
545 			iscsi_fd = open(ISCSI_PATH, O_RDWR);
546 		else
547 			errno = saved_errno;
548 	}
549 	if (iscsi_fd < 0)
550 		log_err(1, "failed to open %s", ISCSI_PATH);
551 
552 	if (dont_daemonize == false) {
553 		if (daemon(0, 0) == -1) {
554 			log_warn("cannot daemonize");
555 			pidfile_remove(pidfh);
556 			exit(1);
557 		}
558 	}
559 
560 	pidfile_write(pidfh);
561 
562 	register_sigchld();
563 
564 	for (;;) {
565 		log_debugx("waiting for request from the kernel");
566 
567 		memset(&request, 0, sizeof(request));
568 		error = ioctl(iscsi_fd, ISCSIDWAIT, &request);
569 		if (error != 0) {
570 			if (errno == EINTR) {
571 				nchildren -= wait_for_children(false);
572 				assert(nchildren >= 0);
573 				continue;
574 			}
575 
576 			log_err(1, "ISCSIDWAIT");
577 		}
578 
579 		if (dont_daemonize) {
580 			log_debugx("not forking due to -d flag; "
581 			    "will exit after servicing a single request");
582 		} else {
583 			nchildren -= wait_for_children(false);
584 			assert(nchildren >= 0);
585 
586 			while (maxproc > 0 && nchildren >= maxproc) {
587 				log_debugx("maxproc limit of %d child processes hit; "
588 				    "waiting for child process to exit", maxproc);
589 				nchildren -= wait_for_children(true);
590 				assert(nchildren >= 0);
591 			}
592 			log_debugx("incoming connection; forking child process #%d",
593 			    nchildren);
594 			nchildren++;
595 
596 			pid = fork();
597 			if (pid < 0)
598 				log_err(1, "fork");
599 			if (pid > 0)
600 				continue;
601 		}
602 
603 		pidfile_close(pidfh);
604 		handle_request(iscsi_fd, &request, timeout);
605 	}
606 
607 	return (0);
608 }
609