xref: /freebsd/usr.sbin/iscsid/iscsid.c (revision 9ecd54f24fe9fa373e07c9fd7c052deb2188f545) 
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/capsicum.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 	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 	if (from_ai != NULL) {
237 		error = bind(conn->conn_socket, from_ai->ai_addr,
238 		    from_ai->ai_addrlen);
239 		if (error != 0) {
240 			fail(conn, strerror(errno));
241 			log_err(1, "failed to bind to %s", from_addr);
242 		}
243 	}
244 	log_debugx("connecting to %s", to_addr);
245 	error = connect(conn->conn_socket, to_ai->ai_addr, to_ai->ai_addrlen);
246 	if (error != 0) {
247 		fail(conn, strerror(errno));
248 		log_err(1, "failed to connect to %s", to_addr);
249 	}
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 	idh.idh_socket = conn->conn_socket;
265 	strlcpy(idh.idh_target_alias, conn->conn_target_alias,
266 	    sizeof(idh.idh_target_alias));
267 	memcpy(idh.idh_isid, conn->conn_isid, sizeof(idh.idh_isid));
268 	idh.idh_statsn = conn->conn_statsn;
269 	idh.idh_header_digest = conn->conn_header_digest;
270 	idh.idh_data_digest = conn->conn_data_digest;
271 	idh.idh_initial_r2t = conn->conn_initial_r2t;
272 	idh.idh_immediate_data = conn->conn_immediate_data;
273 	idh.idh_max_data_segment_length = conn->conn_max_data_segment_length;
274 	idh.idh_max_burst_length = conn->conn_max_burst_length;
275 	idh.idh_first_burst_length = conn->conn_first_burst_length;
276 
277 	error = ioctl(conn->conn_iscsi_fd, ISCSIDHANDOFF, &idh);
278 	if (error != 0)
279 		log_err(1, "ISCSIDHANDOFF");
280 }
281 
282 void
283 fail(const struct connection *conn, const char *reason)
284 {
285 	struct iscsi_daemon_fail idf;
286 	int error;
287 
288 	memset(&idf, 0, sizeof(idf));
289 	idf.idf_session_id = conn->conn_session_id;
290 	strlcpy(idf.idf_reason, reason, sizeof(idf.idf_reason));
291 
292 	error = ioctl(conn->conn_iscsi_fd, ISCSIDFAIL, &idf);
293 	if (error != 0)
294 		log_err(1, "ISCSIDFAIL");
295 }
296 
297 /*
298  * XXX: I CANT INTO LATIN
299  */
300 static void
301 capsicate(struct connection *conn)
302 {
303 	int error;
304 	cap_rights_t rights;
305 #ifdef ICL_KERNEL_PROXY
306 	const unsigned long cmds[] = { ISCSIDCONNECT, ISCSIDSEND, ISCSIDRECEIVE,
307 	    ISCSIDHANDOFF, ISCSIDFAIL, ISCSISADD, ISCSISREMOVE };
308 #else
309 	const unsigned long cmds[] = { ISCSIDHANDOFF, ISCSIDFAIL, ISCSISADD,
310 	    ISCSISREMOVE };
311 #endif
312 
313 	cap_rights_init(&rights, CAP_IOCTL);
314 	error = cap_rights_limit(conn->conn_iscsi_fd, &rights);
315 	if (error != 0 && errno != ENOSYS)
316 		log_err(1, "cap_rights_limit");
317 
318 	error = cap_ioctls_limit(conn->conn_iscsi_fd, cmds,
319 	    sizeof(cmds) / sizeof(cmds[0]));
320 	if (error != 0 && errno != ENOSYS)
321 		log_err(1, "cap_ioctls_limit");
322 
323 	error = cap_enter();
324 	if (error != 0 && errno != ENOSYS)
325 		log_err(1, "cap_enter");
326 
327 	if (cap_sandboxed())
328 		log_debugx("Capsicum capability mode enabled");
329 	else
330 		log_warnx("Capsicum capability mode not supported");
331 }
332 
333 bool
334 timed_out(void)
335 {
336 
337 	return (sigalrm_received);
338 }
339 
340 static void
341 sigalrm_handler(int dummy __unused)
342 {
343 	/*
344 	 * It would be easiest to just log an error and exit.  We can't
345 	 * do this, though, because log_errx() is not signal safe, since
346 	 * it calls syslog(3).  Instead, set a flag checked by pdu_send()
347 	 * and pdu_receive(), to call log_errx() there.  Should they fail
348 	 * to notice, we'll exit here one second later.
349 	 */
350 	if (sigalrm_received) {
351 		/*
352 		 * Oh well.  Just give up and quit.
353 		 */
354 		_exit(2);
355 	}
356 
357 	sigalrm_received = true;
358 }
359 
360 static void
361 set_timeout(int timeout)
362 {
363 	struct sigaction sa;
364 	struct itimerval itv;
365 	int error;
366 
367 	if (timeout <= 0) {
368 		log_debugx("session timeout disabled");
369 		return;
370 	}
371 
372 	bzero(&sa, sizeof(sa));
373 	sa.sa_handler = sigalrm_handler;
374 	sigfillset(&sa.sa_mask);
375 	error = sigaction(SIGALRM, &sa, NULL);
376 	if (error != 0)
377 		log_err(1, "sigaction");
378 
379 	/*
380 	 * First SIGALRM will arive after conf_timeout seconds.
381 	 * If we do nothing, another one will arrive a second later.
382 	 */
383 	bzero(&itv, sizeof(itv));
384 	itv.it_interval.tv_sec = 1;
385 	itv.it_value.tv_sec = timeout;
386 
387 	log_debugx("setting session timeout to %d seconds",
388 	    timeout);
389 	error = setitimer(ITIMER_REAL, &itv, NULL);
390 	if (error != 0)
391 		log_err(1, "setitimer");
392 }
393 
394 static void
395 sigchld_handler(int dummy __unused)
396 {
397 
398 	/*
399 	 * The only purpose of this handler is to make SIGCHLD
400 	 * interrupt the ISCSIDWAIT ioctl(2), so we can call
401 	 * wait_for_children().
402 	 */
403 }
404 
405 static void
406 register_sigchld(void)
407 {
408 	struct sigaction sa;
409 	int error;
410 
411 	bzero(&sa, sizeof(sa));
412 	sa.sa_handler = sigchld_handler;
413 	sigfillset(&sa.sa_mask);
414 	error = sigaction(SIGCHLD, &sa, NULL);
415 	if (error != 0)
416 		log_err(1, "sigaction");
417 
418 }
419 
420 static void
421 handle_request(int iscsi_fd, const struct iscsi_daemon_request *request, int timeout)
422 {
423 	struct connection *conn;
424 
425 	log_set_peer_addr(request->idr_conf.isc_target_addr);
426 	if (request->idr_conf.isc_target[0] != '\0') {
427 		log_set_peer_name(request->idr_conf.isc_target);
428 		setproctitle("%s (%s)", request->idr_conf.isc_target_addr, request->idr_conf.isc_target);
429 	} else {
430 		setproctitle("%s", request->idr_conf.isc_target_addr);
431 	}
432 
433 	conn = connection_new(request->idr_session_id, &request->idr_conf, iscsi_fd);
434 	set_timeout(timeout);
435 	capsicate(conn);
436 	login(conn);
437 	if (conn->conn_conf.isc_discovery != 0)
438 		discovery(conn);
439 	else
440 		handoff(conn);
441 
442 	log_debugx("nothing more to do; exiting");
443 	exit (0);
444 }
445 
446 static int
447 wait_for_children(bool block)
448 {
449 	pid_t pid;
450 	int status;
451 	int num = 0;
452 
453 	for (;;) {
454 		/*
455 		 * If "block" is true, wait for at least one process.
456 		 */
457 		if (block && num == 0)
458 			pid = wait4(-1, &status, 0, NULL);
459 		else
460 			pid = wait4(-1, &status, WNOHANG, NULL);
461 		if (pid <= 0)
462 			break;
463 		if (WIFSIGNALED(status)) {
464 			log_warnx("child process %d terminated with signal %d",
465 			    pid, WTERMSIG(status));
466 		} else if (WEXITSTATUS(status) != 0) {
467 			log_warnx("child process %d terminated with exit status %d",
468 			    pid, WEXITSTATUS(status));
469 		} else {
470 			log_debugx("child process %d terminated gracefully", pid);
471 		}
472 		num++;
473 	}
474 
475 	return (num);
476 }
477 
478 int
479 main(int argc, char **argv)
480 {
481 	int ch, debug = 0, error, iscsi_fd, maxproc = 30, retval, saved_errno,
482 	    timeout = 60;
483 	bool dont_daemonize = false;
484 	struct pidfh *pidfh;
485 	pid_t pid, otherpid;
486 	const char *pidfile_path = DEFAULT_PIDFILE;
487 	struct iscsi_daemon_request request;
488 
489 	while ((ch = getopt(argc, argv, "P:dl:m:t:")) != -1) {
490 		switch (ch) {
491 		case 'P':
492 			pidfile_path = optarg;
493 			break;
494 		case 'd':
495 			dont_daemonize = true;
496 			debug++;
497 			break;
498 		case 'l':
499 			debug = atoi(optarg);
500 			break;
501 		case 'm':
502 			maxproc = atoi(optarg);
503 			break;
504 		case 't':
505 			timeout = atoi(optarg);
506 			break;
507 		case '?':
508 		default:
509 			usage();
510 		}
511 	}
512 	argc -= optind;
513 	if (argc != 0)
514 		usage();
515 
516 	log_init(debug);
517 
518 	pidfh = pidfile_open(pidfile_path, 0600, &otherpid);
519 	if (pidfh == NULL) {
520 		if (errno == EEXIST)
521 			log_errx(1, "daemon already running, pid: %jd.",
522 			    (intmax_t)otherpid);
523 		log_err(1, "cannot open or create pidfile \"%s\"",
524 		    pidfile_path);
525 	}
526 
527 	iscsi_fd = open(ISCSI_PATH, O_RDWR);
528 	if (iscsi_fd < 0 && errno == ENOENT) {
529 		saved_errno = errno;
530 		retval = kldload("iscsi");
531 		if (retval != -1)
532 			iscsi_fd = open(ISCSI_PATH, O_RDWR);
533 		else
534 			errno = saved_errno;
535 	}
536 	if (iscsi_fd < 0)
537 		log_err(1, "failed to open %s", ISCSI_PATH);
538 
539 	if (dont_daemonize == false) {
540 		if (daemon(0, 0) == -1) {
541 			log_warn("cannot daemonize");
542 			pidfile_remove(pidfh);
543 			exit(1);
544 		}
545 	}
546 
547 	pidfile_write(pidfh);
548 
549 	register_sigchld();
550 
551 	for (;;) {
552 		log_debugx("waiting for request from the kernel");
553 
554 		memset(&request, 0, sizeof(request));
555 		error = ioctl(iscsi_fd, ISCSIDWAIT, &request);
556 		if (error != 0) {
557 			if (errno == EINTR) {
558 				nchildren -= wait_for_children(false);
559 				assert(nchildren >= 0);
560 				continue;
561 			}
562 
563 			log_err(1, "ISCSIDWAIT");
564 		}
565 
566 		if (dont_daemonize) {
567 			log_debugx("not forking due to -d flag; "
568 			    "will exit after servicing a single request");
569 		} else {
570 			nchildren -= wait_for_children(false);
571 			assert(nchildren >= 0);
572 
573 			while (maxproc > 0 && nchildren >= maxproc) {
574 				log_debugx("maxproc limit of %d child processes hit; "
575 				    "waiting for child process to exit", maxproc);
576 				nchildren -= wait_for_children(true);
577 				assert(nchildren >= 0);
578 			}
579 			log_debugx("incoming connection; forking child process #%d",
580 			    nchildren);
581 			nchildren++;
582 
583 			pid = fork();
584 			if (pid < 0)
585 				log_err(1, "fork");
586 			if (pid > 0)
587 				continue;
588 		}
589 
590 		pidfile_close(pidfh);
591 		handle_request(iscsi_fd, &request, timeout);
592 	}
593 
594 	return (0);
595 }
596