xref: /freebsd/usr.sbin/iscsid/iscsid.c (revision a0ee8cc636cd5c2374ec44ca71226564ea0bca95) 
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(int iscsi_fd, const struct iscsi_daemon_request *request)
155 {
156 	struct connection *conn;
157 	struct addrinfo *from_ai, *to_ai;
158 	const char *from_addr, *to_addr;
159 #ifdef ICL_KERNEL_PROXY
160 	struct iscsi_daemon_connect idc;
161 #endif
162 	int error, sockbuf;
163 
164 	conn = calloc(1, sizeof(*conn));
165 	if (conn == NULL)
166 		log_err(1, "calloc");
167 
168 	/*
169 	 * Default values, from RFC 3720, section 12.
170 	 */
171 	conn->conn_header_digest = CONN_DIGEST_NONE;
172 	conn->conn_data_digest = CONN_DIGEST_NONE;
173 	conn->conn_initial_r2t = true;
174 	conn->conn_immediate_data = true;
175 	conn->conn_max_data_segment_length = 8192;
176 	conn->conn_max_burst_length = 262144;
177 	conn->conn_first_burst_length = 65536;
178 	conn->conn_iscsi_fd = iscsi_fd;
179 
180 	conn->conn_session_id = request->idr_session_id;
181 	memcpy(&conn->conn_conf, &request->idr_conf, sizeof(conn->conn_conf));
182 	memcpy(&conn->conn_isid, &request->idr_isid, sizeof(conn->conn_isid));
183 	conn->conn_tsih = request->idr_tsih;
184 	memcpy(&conn->conn_limits, &request->idr_limits, sizeof(conn->conn_limits));
185 
186 	from_addr = conn->conn_conf.isc_initiator_addr;
187 	to_addr = conn->conn_conf.isc_target_addr;
188 
189 	if (from_addr[0] != '\0')
190 		resolve_addr(conn, from_addr, &from_ai, true);
191 	else
192 		from_ai = NULL;
193 
194 	resolve_addr(conn, to_addr, &to_ai, false);
195 
196 #ifdef ICL_KERNEL_PROXY
197 	if (conn->conn_conf.isc_iser) {
198 		memset(&idc, 0, sizeof(idc));
199 		idc.idc_session_id = conn->conn_session_id;
200 		if (conn->conn_conf.isc_iser)
201 			idc.idc_iser = 1;
202 		idc.idc_domain = to_ai->ai_family;
203 		idc.idc_socktype = to_ai->ai_socktype;
204 		idc.idc_protocol = to_ai->ai_protocol;
205 		if (from_ai != NULL) {
206 			idc.idc_from_addr = from_ai->ai_addr;
207 			idc.idc_from_addrlen = from_ai->ai_addrlen;
208 		}
209 		idc.idc_to_addr = to_ai->ai_addr;
210 		idc.idc_to_addrlen = to_ai->ai_addrlen;
211 
212 		log_debugx("connecting to %s using ICL kernel proxy", to_addr);
213 		error = ioctl(iscsi_fd, ISCSIDCONNECT, &idc);
214 		if (error != 0) {
215 			fail(conn, strerror(errno));
216 			log_err(1, "failed to connect to %s "
217 			    "using ICL kernel proxy: ISCSIDCONNECT", to_addr);
218 		}
219 
220 		return (conn);
221 	}
222 #endif /* ICL_KERNEL_PROXY */
223 
224 	if (conn->conn_conf.isc_iser) {
225 		fail(conn, "iSER not supported");
226 		log_errx(1, "iscsid(8) compiled without ICL_KERNEL_PROXY "
227 		    "does not support iSER");
228 	}
229 
230 	conn->conn_socket = socket(to_ai->ai_family, to_ai->ai_socktype,
231 	    to_ai->ai_protocol);
232 	if (conn->conn_socket < 0) {
233 		fail(conn, strerror(errno));
234 		log_err(1, "failed to create socket for %s", from_addr);
235 	}
236 	sockbuf = SOCKBUF_SIZE;
237 	if (setsockopt(conn->conn_socket, SOL_SOCKET, SO_RCVBUF,
238 	    &sockbuf, sizeof(sockbuf)) == -1)
239 		log_warn("setsockopt(SO_RCVBUF) failed");
240 	sockbuf = SOCKBUF_SIZE;
241 	if (setsockopt(conn->conn_socket, SOL_SOCKET, SO_SNDBUF,
242 	    &sockbuf, sizeof(sockbuf)) == -1)
243 		log_warn("setsockopt(SO_SNDBUF) failed");
244 	if (from_ai != NULL) {
245 		error = bind(conn->conn_socket, from_ai->ai_addr,
246 		    from_ai->ai_addrlen);
247 		if (error != 0) {
248 			fail(conn, strerror(errno));
249 			log_err(1, "failed to bind to %s", from_addr);
250 		}
251 	}
252 	log_debugx("connecting to %s", to_addr);
253 	error = connect(conn->conn_socket, to_ai->ai_addr, to_ai->ai_addrlen);
254 	if (error != 0) {
255 		fail(conn, strerror(errno));
256 		log_err(1, "failed to connect to %s", to_addr);
257 	}
258 
259 	return (conn);
260 }
261 
262 static void
263 handoff(struct connection *conn)
264 {
265 	struct iscsi_daemon_handoff idh;
266 	int error;
267 
268 	log_debugx("handing off connection to the kernel");
269 
270 	memset(&idh, 0, sizeof(idh));
271 	idh.idh_session_id = conn->conn_session_id;
272 	idh.idh_socket = conn->conn_socket;
273 	strlcpy(idh.idh_target_alias, conn->conn_target_alias,
274 	    sizeof(idh.idh_target_alias));
275 	idh.idh_tsih = conn->conn_tsih;
276 	idh.idh_statsn = conn->conn_statsn;
277 	idh.idh_header_digest = conn->conn_header_digest;
278 	idh.idh_data_digest = conn->conn_data_digest;
279 	idh.idh_initial_r2t = conn->conn_initial_r2t;
280 	idh.idh_immediate_data = conn->conn_immediate_data;
281 	idh.idh_max_data_segment_length = conn->conn_max_data_segment_length;
282 	idh.idh_max_burst_length = conn->conn_max_burst_length;
283 	idh.idh_first_burst_length = conn->conn_first_burst_length;
284 
285 	error = ioctl(conn->conn_iscsi_fd, ISCSIDHANDOFF, &idh);
286 	if (error != 0)
287 		log_err(1, "ISCSIDHANDOFF");
288 }
289 
290 void
291 fail(const struct connection *conn, const char *reason)
292 {
293 	struct iscsi_daemon_fail idf;
294 	int error;
295 
296 	memset(&idf, 0, sizeof(idf));
297 	idf.idf_session_id = conn->conn_session_id;
298 	strlcpy(idf.idf_reason, reason, sizeof(idf.idf_reason));
299 
300 	error = ioctl(conn->conn_iscsi_fd, ISCSIDFAIL, &idf);
301 	if (error != 0)
302 		log_err(1, "ISCSIDFAIL");
303 }
304 
305 /*
306  * XXX: I CANT INTO LATIN
307  */
308 static void
309 capsicate(struct connection *conn)
310 {
311 	int error;
312 	cap_rights_t rights;
313 #ifdef ICL_KERNEL_PROXY
314 	const unsigned long cmds[] = { ISCSIDCONNECT, ISCSIDSEND, ISCSIDRECEIVE,
315 	    ISCSIDHANDOFF, ISCSIDFAIL, ISCSISADD, ISCSISREMOVE, ISCSISMODIFY };
316 #else
317 	const unsigned long cmds[] = { ISCSIDHANDOFF, ISCSIDFAIL, ISCSISADD,
318 	    ISCSISREMOVE, ISCSISMODIFY };
319 #endif
320 
321 	cap_rights_init(&rights, CAP_IOCTL);
322 	error = cap_rights_limit(conn->conn_iscsi_fd, &rights);
323 	if (error != 0 && errno != ENOSYS)
324 		log_err(1, "cap_rights_limit");
325 
326 	error = cap_ioctls_limit(conn->conn_iscsi_fd, cmds,
327 	    sizeof(cmds) / sizeof(cmds[0]));
328 	if (error != 0 && errno != ENOSYS)
329 		log_err(1, "cap_ioctls_limit");
330 
331 	error = cap_enter();
332 	if (error != 0 && errno != ENOSYS)
333 		log_err(1, "cap_enter");
334 
335 	if (cap_sandboxed())
336 		log_debugx("Capsicum capability mode enabled");
337 	else
338 		log_warnx("Capsicum capability mode not supported");
339 }
340 
341 bool
342 timed_out(void)
343 {
344 
345 	return (sigalrm_received);
346 }
347 
348 static void
349 sigalrm_handler(int dummy __unused)
350 {
351 	/*
352 	 * It would be easiest to just log an error and exit.  We can't
353 	 * do this, though, because log_errx() is not signal safe, since
354 	 * it calls syslog(3).  Instead, set a flag checked by pdu_send()
355 	 * and pdu_receive(), to call log_errx() there.  Should they fail
356 	 * to notice, we'll exit here one second later.
357 	 */
358 	if (sigalrm_received) {
359 		/*
360 		 * Oh well.  Just give up and quit.
361 		 */
362 		_exit(2);
363 	}
364 
365 	sigalrm_received = true;
366 }
367 
368 static void
369 set_timeout(int timeout)
370 {
371 	struct sigaction sa;
372 	struct itimerval itv;
373 	int error;
374 
375 	if (timeout <= 0) {
376 		log_debugx("session timeout disabled");
377 		return;
378 	}
379 
380 	bzero(&sa, sizeof(sa));
381 	sa.sa_handler = sigalrm_handler;
382 	sigfillset(&sa.sa_mask);
383 	error = sigaction(SIGALRM, &sa, NULL);
384 	if (error != 0)
385 		log_err(1, "sigaction");
386 
387 	/*
388 	 * First SIGALRM will arive after conf_timeout seconds.
389 	 * If we do nothing, another one will arrive a second later.
390 	 */
391 	bzero(&itv, sizeof(itv));
392 	itv.it_interval.tv_sec = 1;
393 	itv.it_value.tv_sec = timeout;
394 
395 	log_debugx("setting session timeout to %d seconds",
396 	    timeout);
397 	error = setitimer(ITIMER_REAL, &itv, NULL);
398 	if (error != 0)
399 		log_err(1, "setitimer");
400 }
401 
402 static void
403 sigchld_handler(int dummy __unused)
404 {
405 
406 	/*
407 	 * The only purpose of this handler is to make SIGCHLD
408 	 * interrupt the ISCSIDWAIT ioctl(2), so we can call
409 	 * wait_for_children().
410 	 */
411 }
412 
413 static void
414 register_sigchld(void)
415 {
416 	struct sigaction sa;
417 	int error;
418 
419 	bzero(&sa, sizeof(sa));
420 	sa.sa_handler = sigchld_handler;
421 	sigfillset(&sa.sa_mask);
422 	error = sigaction(SIGCHLD, &sa, NULL);
423 	if (error != 0)
424 		log_err(1, "sigaction");
425 
426 }
427 
428 static void
429 handle_request(int iscsi_fd, const struct iscsi_daemon_request *request, int timeout)
430 {
431 	struct connection *conn;
432 
433 	log_set_peer_addr(request->idr_conf.isc_target_addr);
434 	if (request->idr_conf.isc_target[0] != '\0') {
435 		log_set_peer_name(request->idr_conf.isc_target);
436 		setproctitle("%s (%s)", request->idr_conf.isc_target_addr, request->idr_conf.isc_target);
437 	} else {
438 		setproctitle("%s", request->idr_conf.isc_target_addr);
439 	}
440 
441 	conn = connection_new(iscsi_fd, request);
442 	set_timeout(timeout);
443 	capsicate(conn);
444 	login(conn);
445 	if (conn->conn_conf.isc_discovery != 0)
446 		discovery(conn);
447 	else
448 		handoff(conn);
449 
450 	log_debugx("nothing more to do; exiting");
451 	exit (0);
452 }
453 
454 static int
455 wait_for_children(bool block)
456 {
457 	pid_t pid;
458 	int status;
459 	int num = 0;
460 
461 	for (;;) {
462 		/*
463 		 * If "block" is true, wait for at least one process.
464 		 */
465 		if (block && num == 0)
466 			pid = wait4(-1, &status, 0, NULL);
467 		else
468 			pid = wait4(-1, &status, WNOHANG, NULL);
469 		if (pid <= 0)
470 			break;
471 		if (WIFSIGNALED(status)) {
472 			log_warnx("child process %d terminated with signal %d",
473 			    pid, WTERMSIG(status));
474 		} else if (WEXITSTATUS(status) != 0) {
475 			log_warnx("child process %d terminated with exit status %d",
476 			    pid, WEXITSTATUS(status));
477 		} else {
478 			log_debugx("child process %d terminated gracefully", pid);
479 		}
480 		num++;
481 	}
482 
483 	return (num);
484 }
485 
486 int
487 main(int argc, char **argv)
488 {
489 	int ch, debug = 0, error, iscsi_fd, maxproc = 30, retval, saved_errno,
490 	    timeout = 60;
491 	bool dont_daemonize = false;
492 	struct pidfh *pidfh;
493 	pid_t pid, otherpid;
494 	const char *pidfile_path = DEFAULT_PIDFILE;
495 	struct iscsi_daemon_request request;
496 
497 	while ((ch = getopt(argc, argv, "P:dl:m:t:")) != -1) {
498 		switch (ch) {
499 		case 'P':
500 			pidfile_path = optarg;
501 			break;
502 		case 'd':
503 			dont_daemonize = true;
504 			debug++;
505 			break;
506 		case 'l':
507 			debug = atoi(optarg);
508 			break;
509 		case 'm':
510 			maxproc = atoi(optarg);
511 			break;
512 		case 't':
513 			timeout = atoi(optarg);
514 			break;
515 		case '?':
516 		default:
517 			usage();
518 		}
519 	}
520 	argc -= optind;
521 	if (argc != 0)
522 		usage();
523 
524 	log_init(debug);
525 
526 	pidfh = pidfile_open(pidfile_path, 0600, &otherpid);
527 	if (pidfh == NULL) {
528 		if (errno == EEXIST)
529 			log_errx(1, "daemon already running, pid: %jd.",
530 			    (intmax_t)otherpid);
531 		log_err(1, "cannot open or create pidfile \"%s\"",
532 		    pidfile_path);
533 	}
534 
535 	iscsi_fd = open(ISCSI_PATH, O_RDWR);
536 	if (iscsi_fd < 0 && errno == ENOENT) {
537 		saved_errno = errno;
538 		retval = kldload("iscsi");
539 		if (retval != -1)
540 			iscsi_fd = open(ISCSI_PATH, O_RDWR);
541 		else
542 			errno = saved_errno;
543 	}
544 	if (iscsi_fd < 0)
545 		log_err(1, "failed to open %s", ISCSI_PATH);
546 
547 	if (dont_daemonize == false) {
548 		if (daemon(0, 0) == -1) {
549 			log_warn("cannot daemonize");
550 			pidfile_remove(pidfh);
551 			exit(1);
552 		}
553 	}
554 
555 	pidfile_write(pidfh);
556 
557 	register_sigchld();
558 
559 	for (;;) {
560 		log_debugx("waiting for request from the kernel");
561 
562 		memset(&request, 0, sizeof(request));
563 		error = ioctl(iscsi_fd, ISCSIDWAIT, &request);
564 		if (error != 0) {
565 			if (errno == EINTR) {
566 				nchildren -= wait_for_children(false);
567 				assert(nchildren >= 0);
568 				continue;
569 			}
570 
571 			log_err(1, "ISCSIDWAIT");
572 		}
573 
574 		if (dont_daemonize) {
575 			log_debugx("not forking due to -d flag; "
576 			    "will exit after servicing a single request");
577 		} else {
578 			nchildren -= wait_for_children(false);
579 			assert(nchildren >= 0);
580 
581 			while (maxproc > 0 && nchildren >= maxproc) {
582 				log_debugx("maxproc limit of %d child processes hit; "
583 				    "waiting for child process to exit", maxproc);
584 				nchildren -= wait_for_children(true);
585 				assert(nchildren >= 0);
586 			}
587 			log_debugx("incoming connection; forking child process #%d",
588 			    nchildren);
589 			nchildren++;
590 
591 			pid = fork();
592 			if (pid < 0)
593 				log_err(1, "fork");
594 			if (pid > 0)
595 				continue;
596 		}
597 
598 		pidfile_close(pidfh);
599 		handle_request(iscsi_fd, &request, timeout);
600 	}
601 
602 	return (0);
603 }
604