iscsid.c revision 262846 
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: stable/10/usr.sbin/iscsid/iscsid.c 262846 2014-03-06 11:15:54Z trasz $
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
56static volatile bool sigalrm_received = false;
57
58static int nchildren = 0;
59
60static void
61usage(void)
62{
63
64	fprintf(stderr, "usage: iscsid [-P pidfile][-d][-m maxproc][-t timeout]\n");
65	exit(1);
66}
67
68char *
69checked_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
79static void
80resolve_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
151static struct connection *
152connection_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
254static void
255handoff(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
284void
285fail(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 */
302static void
303capsicate(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
335bool
336timed_out(void)
337{
338
339	return (sigalrm_received);
340}
341
342static void
343sigalrm_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
362static void
363set_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
396static void
397sigchld_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
407static void
408register_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
422static void
423handle_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
448static int
449wait_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
480int
481main(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