iscsid.c revision 270888 
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: stable/10/usr.sbin/iscsid/iscsid.c 270888 2014-08-31 20:21:08Z trasz $");
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/capability.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
58static volatile bool sigalrm_received = false;
59
60static int nchildren = 0;
61
62static void
63usage(void)
64{
65
66	fprintf(stderr, "usage: iscsid [-P pidfile][-d][-m maxproc][-t timeout]\n");
67	exit(1);
68}
69
70char *
71checked_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
81static void
82resolve_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
153static struct connection *
154connection_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;
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	if (from_ai != NULL) {
241		error = bind(conn->conn_socket, from_ai->ai_addr,
242		    from_ai->ai_addrlen);
243		if (error != 0) {
244			fail(conn, strerror(errno));
245			log_err(1, "failed to bind to %s", from_addr);
246		}
247	}
248	log_debugx("connecting to %s", to_addr);
249	error = connect(conn->conn_socket, to_ai->ai_addr, to_ai->ai_addrlen);
250	if (error != 0) {
251		fail(conn, strerror(errno));
252		log_err(1, "failed to connect to %s", to_addr);
253	}
254
255	return (conn);
256}
257
258static void
259handoff(struct connection *conn)
260{
261	struct iscsi_daemon_handoff idh;
262	int error;
263
264	log_debugx("handing off connection to the kernel");
265
266	memset(&idh, 0, sizeof(idh));
267	idh.idh_session_id = conn->conn_session_id;
268	idh.idh_socket = conn->conn_socket;
269	strlcpy(idh.idh_target_alias, conn->conn_target_alias,
270	    sizeof(idh.idh_target_alias));
271	idh.idh_tsih = conn->conn_tsih;
272	idh.idh_statsn = conn->conn_statsn;
273	idh.idh_header_digest = conn->conn_header_digest;
274	idh.idh_data_digest = conn->conn_data_digest;
275	idh.idh_initial_r2t = conn->conn_initial_r2t;
276	idh.idh_immediate_data = conn->conn_immediate_data;
277	idh.idh_max_data_segment_length = conn->conn_max_data_segment_length;
278	idh.idh_max_burst_length = conn->conn_max_burst_length;
279	idh.idh_first_burst_length = conn->conn_first_burst_length;
280
281	error = ioctl(conn->conn_iscsi_fd, ISCSIDHANDOFF, &idh);
282	if (error != 0)
283		log_err(1, "ISCSIDHANDOFF");
284}
285
286void
287fail(const struct connection *conn, const char *reason)
288{
289	struct iscsi_daemon_fail idf;
290	int error;
291
292	memset(&idf, 0, sizeof(idf));
293	idf.idf_session_id = conn->conn_session_id;
294	strlcpy(idf.idf_reason, reason, sizeof(idf.idf_reason));
295
296	error = ioctl(conn->conn_iscsi_fd, ISCSIDFAIL, &idf);
297	if (error != 0)
298		log_err(1, "ISCSIDFAIL");
299}
300
301/*
302 * XXX: I CANT INTO LATIN
303 */
304static void
305capsicate(struct connection *conn)
306{
307	int error;
308	cap_rights_t rights;
309#ifdef ICL_KERNEL_PROXY
310	const unsigned long cmds[] = { ISCSIDCONNECT, ISCSIDSEND, ISCSIDRECEIVE,
311	    ISCSIDHANDOFF, ISCSIDFAIL, ISCSISADD, ISCSISREMOVE, ISCSISMODIFY };
312#else
313	const unsigned long cmds[] = { ISCSIDHANDOFF, ISCSIDFAIL, ISCSISADD,
314	    ISCSISREMOVE, ISCSISMODIFY };
315#endif
316
317	cap_rights_init(&rights, CAP_IOCTL);
318	error = cap_rights_limit(conn->conn_iscsi_fd, &rights);
319	if (error != 0 && errno != ENOSYS)
320		log_err(1, "cap_rights_limit");
321
322	error = cap_ioctls_limit(conn->conn_iscsi_fd, cmds,
323	    sizeof(cmds) / sizeof(cmds[0]));
324	if (error != 0 && errno != ENOSYS)
325		log_err(1, "cap_ioctls_limit");
326
327	error = cap_enter();
328	if (error != 0 && errno != ENOSYS)
329		log_err(1, "cap_enter");
330
331	if (cap_sandboxed())
332		log_debugx("Capsicum capability mode enabled");
333	else
334		log_warnx("Capsicum capability mode not supported");
335}
336
337bool
338timed_out(void)
339{
340
341	return (sigalrm_received);
342}
343
344static void
345sigalrm_handler(int dummy __unused)
346{
347	/*
348	 * It would be easiest to just log an error and exit.  We can't
349	 * do this, though, because log_errx() is not signal safe, since
350	 * it calls syslog(3).  Instead, set a flag checked by pdu_send()
351	 * and pdu_receive(), to call log_errx() there.  Should they fail
352	 * to notice, we'll exit here one second later.
353	 */
354	if (sigalrm_received) {
355		/*
356		 * Oh well.  Just give up and quit.
357		 */
358		_exit(2);
359	}
360
361	sigalrm_received = true;
362}
363
364static void
365set_timeout(int timeout)
366{
367	struct sigaction sa;
368	struct itimerval itv;
369	int error;
370
371	if (timeout <= 0) {
372		log_debugx("session timeout disabled");
373		return;
374	}
375
376	bzero(&sa, sizeof(sa));
377	sa.sa_handler = sigalrm_handler;
378	sigfillset(&sa.sa_mask);
379	error = sigaction(SIGALRM, &sa, NULL);
380	if (error != 0)
381		log_err(1, "sigaction");
382
383	/*
384	 * First SIGALRM will arive after conf_timeout seconds.
385	 * If we do nothing, another one will arrive a second later.
386	 */
387	bzero(&itv, sizeof(itv));
388	itv.it_interval.tv_sec = 1;
389	itv.it_value.tv_sec = timeout;
390
391	log_debugx("setting session timeout to %d seconds",
392	    timeout);
393	error = setitimer(ITIMER_REAL, &itv, NULL);
394	if (error != 0)
395		log_err(1, "setitimer");
396}
397
398static void
399sigchld_handler(int dummy __unused)
400{
401
402	/*
403	 * The only purpose of this handler is to make SIGCHLD
404	 * interrupt the ISCSIDWAIT ioctl(2), so we can call
405	 * wait_for_children().
406	 */
407}
408
409static void
410register_sigchld(void)
411{
412	struct sigaction sa;
413	int error;
414
415	bzero(&sa, sizeof(sa));
416	sa.sa_handler = sigchld_handler;
417	sigfillset(&sa.sa_mask);
418	error = sigaction(SIGCHLD, &sa, NULL);
419	if (error != 0)
420		log_err(1, "sigaction");
421
422}
423
424static void
425handle_request(int iscsi_fd, const struct iscsi_daemon_request *request, int timeout)
426{
427	struct connection *conn;
428
429	log_set_peer_addr(request->idr_conf.isc_target_addr);
430	if (request->idr_conf.isc_target[0] != '\0') {
431		log_set_peer_name(request->idr_conf.isc_target);
432		setproctitle("%s (%s)", request->idr_conf.isc_target_addr, request->idr_conf.isc_target);
433	} else {
434		setproctitle("%s", request->idr_conf.isc_target_addr);
435	}
436
437	conn = connection_new(request->idr_session_id, request->idr_isid,
438	    request->idr_tsih, &request->idr_conf, iscsi_fd);
439	set_timeout(timeout);
440	capsicate(conn);
441	login(conn);
442	if (conn->conn_conf.isc_discovery != 0)
443		discovery(conn);
444	else
445		handoff(conn);
446
447	log_debugx("nothing more to do; exiting");
448	exit (0);
449}
450
451static int
452wait_for_children(bool block)
453{
454	pid_t pid;
455	int status;
456	int num = 0;
457
458	for (;;) {
459		/*
460		 * If "block" is true, wait for at least one process.
461		 */
462		if (block && num == 0)
463			pid = wait4(-1, &status, 0, NULL);
464		else
465			pid = wait4(-1, &status, WNOHANG, NULL);
466		if (pid <= 0)
467			break;
468		if (WIFSIGNALED(status)) {
469			log_warnx("child process %d terminated with signal %d",
470			    pid, WTERMSIG(status));
471		} else if (WEXITSTATUS(status) != 0) {
472			log_warnx("child process %d terminated with exit status %d",
473			    pid, WEXITSTATUS(status));
474		} else {
475			log_debugx("child process %d terminated gracefully", pid);
476		}
477		num++;
478	}
479
480	return (num);
481}
482
483int
484main(int argc, char **argv)
485{
486	int ch, debug = 0, error, iscsi_fd, maxproc = 30, retval, saved_errno,
487	    timeout = 60;
488	bool dont_daemonize = false;
489	struct pidfh *pidfh;
490	pid_t pid, otherpid;
491	const char *pidfile_path = DEFAULT_PIDFILE;
492	struct iscsi_daemon_request request;
493
494	while ((ch = getopt(argc, argv, "P:dl:m:t:")) != -1) {
495		switch (ch) {
496		case 'P':
497			pidfile_path = optarg;
498			break;
499		case 'd':
500			dont_daemonize = true;
501			debug++;
502			break;
503		case 'l':
504			debug = atoi(optarg);
505			break;
506		case 'm':
507			maxproc = atoi(optarg);
508			break;
509		case 't':
510			timeout = atoi(optarg);
511			break;
512		case '?':
513		default:
514			usage();
515		}
516	}
517	argc -= optind;
518	if (argc != 0)
519		usage();
520
521	log_init(debug);
522
523	pidfh = pidfile_open(pidfile_path, 0600, &otherpid);
524	if (pidfh == NULL) {
525		if (errno == EEXIST)
526			log_errx(1, "daemon already running, pid: %jd.",
527			    (intmax_t)otherpid);
528		log_err(1, "cannot open or create pidfile \"%s\"",
529		    pidfile_path);
530	}
531
532	iscsi_fd = open(ISCSI_PATH, O_RDWR);
533	if (iscsi_fd < 0 && errno == ENOENT) {
534		saved_errno = errno;
535		retval = kldload("iscsi");
536		if (retval != -1)
537			iscsi_fd = open(ISCSI_PATH, O_RDWR);
538		else
539			errno = saved_errno;
540	}
541	if (iscsi_fd < 0)
542		log_err(1, "failed to open %s", ISCSI_PATH);
543
544	if (dont_daemonize == false) {
545		if (daemon(0, 0) == -1) {
546			log_warn("cannot daemonize");
547			pidfile_remove(pidfh);
548			exit(1);
549		}
550	}
551
552	pidfile_write(pidfh);
553
554	register_sigchld();
555
556	for (;;) {
557		log_debugx("waiting for request from the kernel");
558
559		memset(&request, 0, sizeof(request));
560		error = ioctl(iscsi_fd, ISCSIDWAIT, &request);
561		if (error != 0) {
562			if (errno == EINTR) {
563				nchildren -= wait_for_children(false);
564				assert(nchildren >= 0);
565				continue;
566			}
567
568			log_err(1, "ISCSIDWAIT");
569		}
570
571		if (dont_daemonize) {
572			log_debugx("not forking due to -d flag; "
573			    "will exit after servicing a single request");
574		} else {
575			nchildren -= wait_for_children(false);
576			assert(nchildren >= 0);
577
578			while (maxproc > 0 && nchildren >= maxproc) {
579				log_debugx("maxproc limit of %d child processes hit; "
580				    "waiting for child process to exit", maxproc);
581				nchildren -= wait_for_children(true);
582				assert(nchildren >= 0);
583			}
584			log_debugx("incoming connection; forking child process #%d",
585			    nchildren);
586			nchildren++;
587
588			pid = fork();
589			if (pid < 0)
590				log_err(1, "fork");
591			if (pid > 0)
592				continue;
593		}
594
595		pidfile_close(pidfh);
596		handle_request(iscsi_fd, &request, timeout);
597	}
598
599	return (0);
600}
601