xref: /freebsd/usr.sbin/iscsid/iscsid.c (revision 3a92d97ff0f22d21608e1c19b83104c4937523b6) 
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  * $FreeBSD$
30  */
31 
32 #include <sys/types.h>
33 #include <sys/time.h>
34 #include <sys/ioctl.h>
35 #include <sys/param.h>
36 #include <sys/linker.h>
37 #include <sys/socket.h>
38 #include <sys/capability.h>
39 #include <sys/wait.h>
40 #include <assert.h>
41 #include <errno.h>
42 #include <fcntl.h>
43 #include <netdb.h>
44 #include <signal.h>
45 #include <stdbool.h>
46 #include <stdint.h>
47 #include <stdio.h>
48 #include <stdlib.h>
49 #include <string.h>
50 #include <unistd.h>
51 
52 #include <libutil.h>
53 
54 #include "iscsid.h"
55 
56 static volatile bool sigalrm_received = false;
57 
58 static int nchildren = 0;
59 
60 static void
61 usage(void)
62 {
63 
64 	fprintf(stderr, "usage: iscsid [-P pidfile][-d][-m maxproc][-t timeout]\n");
65 	exit(1);
66 }
67 
68 char *
69 checked_strdup(const char *s)
70 {
71 	char *c;
72 
73 	c = strdup(s);
74 	if (c == NULL)
75 		log_err(1, "strdup");
76 	return (c);
77 }
78 
79 static void
80 resolve_addr(const struct connection *conn, const char *address,
81     struct addrinfo **ai, bool initiator_side)
82 {
83 	struct addrinfo hints;
84 	char *arg, *addr, *ch;
85 	const char *port;
86 	int error, colons = 0;
87 
88 	arg = checked_strdup(address);
89 
90 	if (arg[0] == '\0') {
91 		fail(conn, "empty address");
92 		log_errx(1, "empty address");
93 	}
94 	if (arg[0] == '[') {
95 		/*
96 		 * IPv6 address in square brackets, perhaps with port.
97 		 */
98 		arg++;
99 		addr = strsep(&arg, "]");
100 		if (arg == NULL) {
101 			fail(conn, "malformed address");
102 			log_errx(1, "malformed address %s", address);
103 		}
104 		if (arg[0] == '\0') {
105 			port = NULL;
106 		} else if (arg[0] == ':') {
107 			port = arg + 1;
108 		} else {
109 			fail(conn, "malformed address");
110 			log_errx(1, "malformed address %s", address);
111 		}
112 	} else {
113 		/*
114 		 * Either IPv6 address without brackets - and without
115 		 * a port - or IPv4 address.  Just count the colons.
116 		 */
117 		for (ch = arg; *ch != '\0'; ch++) {
118 			if (*ch == ':')
119 				colons++;
120 		}
121 		if (colons > 1) {
122 			addr = arg;
123 			port = NULL;
124 		} else {
125 			addr = strsep(&arg, ":");
126 			if (arg == NULL)
127 				port = NULL;
128 			else
129 				port = arg;
130 		}
131 	}
132 
133 	if (port == NULL && !initiator_side)
134 		port = "3260";
135 
136 	memset(&hints, 0, sizeof(hints));
137 	hints.ai_family = PF_UNSPEC;
138 	hints.ai_socktype = SOCK_STREAM;
139 	hints.ai_flags = AI_ADDRCONFIG | AI_NUMERICSERV;
140 	if (initiator_side)
141 		hints.ai_flags |= AI_PASSIVE;
142 
143 	error = getaddrinfo(addr, port, &hints, ai);
144 	if (error != 0) {
145 		fail(conn, gai_strerror(error));
146 		log_errx(1, "getaddrinfo for %s failed: %s",
147 		    address, gai_strerror(error));
148 	}
149 }
150 
151 static struct connection *
152 connection_new(unsigned int session_id, const struct iscsi_session_conf *conf,
153     int iscsi_fd)
154 {
155 	struct connection *conn;
156 	struct addrinfo *from_ai, *to_ai;
157 	const char *from_addr, *to_addr;
158 #ifdef ICL_KERNEL_PROXY
159 	struct iscsi_daemon_connect idc;
160 #endif
161 	int error;
162 
163 	conn = calloc(1, sizeof(*conn));
164 	if (conn == NULL)
165 		log_err(1, "calloc");
166 
167 	/*
168 	 * Default values, from RFC 3720, section 12.
169 	 */
170 	conn->conn_header_digest = CONN_DIGEST_NONE;
171 	conn->conn_data_digest = CONN_DIGEST_NONE;
172 	conn->conn_initial_r2t = true;
173 	conn->conn_immediate_data = true;
174 	conn->conn_max_data_segment_length = 8192;
175 	conn->conn_max_burst_length = 262144;
176 	conn->conn_first_burst_length = 65536;
177 
178 	conn->conn_session_id = session_id;
179 	conn->conn_iscsi_fd = iscsi_fd;
180 
181 	/*
182 	 * XXX: Should we sanitize this somehow?
183 	 */
184 	memcpy(&conn->conn_conf, conf, sizeof(conn->conn_conf));
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 
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 using ICL kernel proxy",
217 		    to_addr);
218 	}
219 
220 #else /* !ICL_KERNEL_PROXY */
221 
222 	if (conn->conn_conf.isc_iser) {
223 		fail(conn, "iSER not supported");
224 		log_errx(1, "iscsid(8) compiled without ICL_KERNEL_PROXY "
225 		    "does not support iSER");
226 	}
227 
228 	conn->conn_socket = socket(to_ai->ai_family, to_ai->ai_socktype,
229 	    to_ai->ai_protocol);
230 	if (conn->conn_socket < 0) {
231 		fail(conn, strerror(errno));
232 		log_err(1, "failed to create socket for %s", from_addr);
233 	}
234 	if (from_ai != NULL) {
235 		error = bind(conn->conn_socket, from_ai->ai_addr,
236 		    from_ai->ai_addrlen);
237 		if (error != 0) {
238 			fail(conn, strerror(errno));
239 			log_err(1, "failed to bind to %s", from_addr);
240 		}
241 	}
242 	log_debugx("connecting to %s", to_addr);
243 	error = connect(conn->conn_socket, to_ai->ai_addr, to_ai->ai_addrlen);
244 	if (error != 0) {
245 		fail(conn, strerror(errno));
246 		log_err(1, "failed to connect to %s", to_addr);
247 	}
248 
249 #endif /* !ICL_KERNEL_PROXY */
250 
251 	return (conn);
252 }
253 
254 static void
255 handoff(struct connection *conn)
256 {
257 	struct iscsi_daemon_handoff idh;
258 	int error;
259 
260 	log_debugx("handing off connection to the kernel");
261 
262 	memset(&idh, 0, sizeof(idh));
263 	idh.idh_session_id = conn->conn_session_id;
264 #ifndef ICL_KERNEL_PROXY
265 	idh.idh_socket = conn->conn_socket;
266 #endif
267 	strlcpy(idh.idh_target_alias, conn->conn_target_alias,
268 	    sizeof(idh.idh_target_alias));
269 	memcpy(idh.idh_isid, conn->conn_isid, sizeof(idh.idh_isid));
270 	idh.idh_statsn = conn->conn_statsn;
271 	idh.idh_header_digest = conn->conn_header_digest;
272 	idh.idh_data_digest = conn->conn_data_digest;
273 	idh.idh_initial_r2t = conn->conn_initial_r2t;
274 	idh.idh_immediate_data = conn->conn_immediate_data;
275 	idh.idh_max_data_segment_length = conn->conn_max_data_segment_length;
276 	idh.idh_max_burst_length = conn->conn_max_burst_length;
277 	idh.idh_first_burst_length = conn->conn_first_burst_length;
278 
279 	error = ioctl(conn->conn_iscsi_fd, ISCSIDHANDOFF, &idh);
280 	if (error != 0)
281 		log_err(1, "ISCSIDHANDOFF");
282 }
283 
284 void
285 fail(const struct connection *conn, const char *reason)
286 {
287 	struct iscsi_daemon_fail idf;
288 	int error;
289 
290 	memset(&idf, 0, sizeof(idf));
291 	idf.idf_session_id = conn->conn_session_id;
292 	strlcpy(idf.idf_reason, reason, sizeof(idf.idf_reason));
293 
294 	error = ioctl(conn->conn_iscsi_fd, ISCSIDFAIL, &idf);
295 	if (error != 0)
296 		log_err(1, "ISCSIDFAIL");
297 }
298 
299 /*
300  * XXX: I CANT INTO LATIN
301  */
302 static void
303 capsicate(struct connection *conn)
304 {
305 	int error;
306 	cap_rights_t rights;
307 #ifdef ICL_KERNEL_PROXY
308 	const unsigned long cmds[] = { ISCSIDCONNECT, ISCSIDSEND, ISCSIDRECEIVE,
309 	    ISCSIDHANDOFF, ISCSIDFAIL, ISCSISADD, ISCSISREMOVE };
310 #else
311 	const unsigned long cmds[] = { ISCSIDHANDOFF, ISCSIDFAIL, ISCSISADD,
312 	    ISCSISREMOVE };
313 #endif
314 
315 	cap_rights_init(&rights, CAP_IOCTL);
316 	error = cap_rights_limit(conn->conn_iscsi_fd, &rights);
317 	if (error != 0 && errno != ENOSYS)
318 		log_err(1, "cap_rights_limit");
319 
320 	error = cap_ioctls_limit(conn->conn_iscsi_fd, cmds,
321 	    sizeof(cmds) / sizeof(cmds[0]));
322 	if (error != 0 && errno != ENOSYS)
323 		log_err(1, "cap_ioctls_limit");
324 
325 	error = cap_enter();
326 	if (error != 0 && errno != ENOSYS)
327 		log_err(1, "cap_enter");
328 
329 	if (cap_sandboxed())
330 		log_debugx("Capsicum capability mode enabled");
331 	else
332 		log_warnx("Capsicum capability mode not supported");
333 }
334 
335 bool
336 timed_out(void)
337 {
338 
339 	return (sigalrm_received);
340 }
341 
342 static void
343 sigalrm_handler(int dummy __unused)
344 {
345 	/*
346 	 * It would be easiest to just log an error and exit.  We can't
347 	 * do this, though, because log_errx() is not signal safe, since
348 	 * it calls syslog(3).  Instead, set a flag checked by pdu_send()
349 	 * and pdu_receive(), to call log_errx() there.  Should they fail
350 	 * to notice, we'll exit here one second later.
351 	 */
352 	if (sigalrm_received) {
353 		/*
354 		 * Oh well.  Just give up and quit.
355 		 */
356 		_exit(2);
357 	}
358 
359 	sigalrm_received = true;
360 }
361 
362 static void
363 set_timeout(int timeout)
364 {
365 	struct sigaction sa;
366 	struct itimerval itv;
367 	int error;
368 
369 	if (timeout <= 0) {
370 		log_debugx("session timeout disabled");
371 		return;
372 	}
373 
374 	bzero(&sa, sizeof(sa));
375 	sa.sa_handler = sigalrm_handler;
376 	sigfillset(&sa.sa_mask);
377 	error = sigaction(SIGALRM, &sa, NULL);
378 	if (error != 0)
379 		log_err(1, "sigaction");
380 
381 	/*
382 	 * First SIGALRM will arive after conf_timeout seconds.
383 	 * If we do nothing, another one will arrive a second later.
384 	 */
385 	bzero(&itv, sizeof(itv));
386 	itv.it_interval.tv_sec = 1;
387 	itv.it_value.tv_sec = timeout;
388 
389 	log_debugx("setting session timeout to %d seconds",
390 	    timeout);
391 	error = setitimer(ITIMER_REAL, &itv, NULL);
392 	if (error != 0)
393 		log_err(1, "setitimer");
394 }
395 
396 static void
397 sigchld_handler(int dummy __unused)
398 {
399 
400 	/*
401 	 * The only purpose of this handler is to make SIGCHLD
402 	 * interrupt the ISCSIDWAIT ioctl(2), so we can call
403 	 * wait_for_children().
404 	 */
405 }
406 
407 static void
408 register_sigchld(void)
409 {
410 	struct sigaction sa;
411 	int error;
412 
413 	bzero(&sa, sizeof(sa));
414 	sa.sa_handler = sigchld_handler;
415 	sigfillset(&sa.sa_mask);
416 	error = sigaction(SIGCHLD, &sa, NULL);
417 	if (error != 0)
418 		log_err(1, "sigaction");
419 
420 }
421 
422 static void
423 handle_request(int iscsi_fd, const struct iscsi_daemon_request *request, int timeout)
424 {
425 	struct connection *conn;
426 
427 	log_set_peer_addr(request->idr_conf.isc_target_addr);
428 	if (request->idr_conf.isc_target[0] != '\0') {
429 		log_set_peer_name(request->idr_conf.isc_target);
430 		setproctitle("%s (%s)", request->idr_conf.isc_target_addr, request->idr_conf.isc_target);
431 	} else {
432 		setproctitle("%s", request->idr_conf.isc_target_addr);
433 	}
434 
435 	conn = connection_new(request->idr_session_id, &request->idr_conf, iscsi_fd);
436 	set_timeout(timeout);
437 	capsicate(conn);
438 	login(conn);
439 	if (conn->conn_conf.isc_discovery != 0)
440 		discovery(conn);
441 	else
442 		handoff(conn);
443 
444 	log_debugx("nothing more to do; exiting");
445 	exit (0);
446 }
447 
448 static int
449 wait_for_children(bool block)
450 {
451 	pid_t pid;
452 	int status;
453 	int num = 0;
454 
455 	for (;;) {
456 		/*
457 		 * If "block" is true, wait for at least one process.
458 		 */
459 		if (block && num == 0)
460 			pid = wait4(-1, &status, 0, NULL);
461 		else
462 			pid = wait4(-1, &status, WNOHANG, NULL);
463 		if (pid <= 0)
464 			break;
465 		if (WIFSIGNALED(status)) {
466 			log_warnx("child process %d terminated with signal %d",
467 			    pid, WTERMSIG(status));
468 		} else if (WEXITSTATUS(status) != 0) {
469 			log_warnx("child process %d terminated with exit status %d",
470 			    pid, WEXITSTATUS(status));
471 		} else {
472 			log_debugx("child process %d terminated gracefully", pid);
473 		}
474 		num++;
475 	}
476 
477 	return (num);
478 }
479 
480 int
481 main(int argc, char **argv)
482 {
483 	int ch, debug = 0, error, iscsi_fd, maxproc = 30, retval, saved_errno,
484 	    timeout = 60;
485 	bool dont_daemonize = false;
486 	struct pidfh *pidfh;
487 	pid_t pid, otherpid;
488 	const char *pidfile_path = DEFAULT_PIDFILE;
489 	struct iscsi_daemon_request request;
490 
491 	while ((ch = getopt(argc, argv, "P:dl:m:t:")) != -1) {
492 		switch (ch) {
493 		case 'P':
494 			pidfile_path = optarg;
495 			break;
496 		case 'd':
497 			dont_daemonize = true;
498 			debug++;
499 			break;
500 		case 'l':
501 			debug = atoi(optarg);
502 			break;
503 		case 'm':
504 			maxproc = atoi(optarg);
505 			break;
506 		case 't':
507 			timeout = atoi(optarg);
508 			break;
509 		case '?':
510 		default:
511 			usage();
512 		}
513 	}
514 	argc -= optind;
515 	if (argc != 0)
516 		usage();
517 
518 	log_init(debug);
519 
520 	pidfh = pidfile_open(pidfile_path, 0600, &otherpid);
521 	if (pidfh == NULL) {
522 		if (errno == EEXIST)
523 			log_errx(1, "daemon already running, pid: %jd.",
524 			    (intmax_t)otherpid);
525 		log_err(1, "cannot open or create pidfile \"%s\"",
526 		    pidfile_path);
527 	}
528 
529 	iscsi_fd = open(ISCSI_PATH, O_RDWR);
530 	if (iscsi_fd < 0 && errno == ENOENT) {
531 		saved_errno = errno;
532 		retval = kldload("iscsi");
533 		if (retval != -1)
534 			iscsi_fd = open(ISCSI_PATH, O_RDWR);
535 		else
536 			errno = saved_errno;
537 	}
538 	if (iscsi_fd < 0)
539 		log_err(1, "failed to open %s", ISCSI_PATH);
540 
541 	if (dont_daemonize == false) {
542 		if (daemon(0, 0) == -1) {
543 			log_warn("cannot daemonize");
544 			pidfile_remove(pidfh);
545 			exit(1);
546 		}
547 	}
548 
549 	pidfile_write(pidfh);
550 
551 	register_sigchld();
552 
553 	for (;;) {
554 		log_debugx("waiting for request from the kernel");
555 
556 		memset(&request, 0, sizeof(request));
557 		error = ioctl(iscsi_fd, ISCSIDWAIT, &request);
558 		if (error != 0) {
559 			if (errno == EINTR) {
560 				nchildren -= wait_for_children(false);
561 				assert(nchildren >= 0);
562 				continue;
563 			}
564 
565 			log_err(1, "ISCSIDWAIT");
566 		}
567 
568 		if (dont_daemonize) {
569 			log_debugx("not forking due to -d flag; "
570 			    "will exit after servicing a single request");
571 		} else {
572 			nchildren -= wait_for_children(false);
573 			assert(nchildren >= 0);
574 
575 			while (maxproc > 0 && nchildren >= maxproc) {
576 				log_debugx("maxproc limit of %d child processes hit; "
577 				    "waiting for child process to exit", maxproc);
578 				nchildren -= wait_for_children(true);
579 				assert(nchildren >= 0);
580 			}
581 			log_debugx("incoming connection; forking child process #%d",
582 			    nchildren);
583 			nchildren++;
584 
585 			pid = fork();
586 			if (pid < 0)
587 				log_err(1, "fork");
588 			if (pid > 0)
589 				continue;
590 		}
591 
592 		pidfile_close(pidfh);
593 		handle_request(iscsi_fd, &request, timeout);
594 	}
595 
596 	return (0);
597 }
598