iscsid.c revision 280250 
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 280250 2015-03-19 12:32:48Z rwatson $");
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
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, sockbuf;
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	sockbuf = SOCKBUF_SIZE;
241	if (setsockopt(conn->conn_socket, SOL_SOCKET, SO_RCVBUF,
242	    &sockbuf, sizeof(sockbuf)) == -1)
243		log_warn("setsockopt(SO_RCVBUF) failed");
244	sockbuf = SOCKBUF_SIZE;
245	if (setsockopt(conn->conn_socket, SOL_SOCKET, SO_SNDBUF,
246	    &sockbuf, sizeof(sockbuf)) == -1)
247		log_warn("setsockopt(SO_SNDBUF) failed");
248	if (from_ai != NULL) {
249		error = bind(conn->conn_socket, from_ai->ai_addr,
250		    from_ai->ai_addrlen);
251		if (error != 0) {
252			fail(conn, strerror(errno));
253			log_err(1, "failed to bind to %s", from_addr);
254		}
255	}
256	log_debugx("connecting to %s", to_addr);
257	error = connect(conn->conn_socket, to_ai->ai_addr, to_ai->ai_addrlen);
258	if (error != 0) {
259		fail(conn, strerror(errno));
260		log_err(1, "failed to connect to %s", to_addr);
261	}
262
263	return (conn);
264}
265
266static void
267handoff(struct connection *conn)
268{
269	struct iscsi_daemon_handoff idh;
270	int error;
271
272	log_debugx("handing off connection to the kernel");
273
274	memset(&idh, 0, sizeof(idh));
275	idh.idh_session_id = conn->conn_session_id;
276	idh.idh_socket = conn->conn_socket;
277	strlcpy(idh.idh_target_alias, conn->conn_target_alias,
278	    sizeof(idh.idh_target_alias));
279	idh.idh_tsih = conn->conn_tsih;
280	idh.idh_statsn = conn->conn_statsn;
281	idh.idh_header_digest = conn->conn_header_digest;
282	idh.idh_data_digest = conn->conn_data_digest;
283	idh.idh_initial_r2t = conn->conn_initial_r2t;
284	idh.idh_immediate_data = conn->conn_immediate_data;
285	idh.idh_max_data_segment_length = conn->conn_max_data_segment_length;
286	idh.idh_max_burst_length = conn->conn_max_burst_length;
287	idh.idh_first_burst_length = conn->conn_first_burst_length;
288
289	error = ioctl(conn->conn_iscsi_fd, ISCSIDHANDOFF, &idh);
290	if (error != 0)
291		log_err(1, "ISCSIDHANDOFF");
292}
293
294void
295fail(const struct connection *conn, const char *reason)
296{
297	struct iscsi_daemon_fail idf;
298	int error;
299
300	memset(&idf, 0, sizeof(idf));
301	idf.idf_session_id = conn->conn_session_id;
302	strlcpy(idf.idf_reason, reason, sizeof(idf.idf_reason));
303
304	error = ioctl(conn->conn_iscsi_fd, ISCSIDFAIL, &idf);
305	if (error != 0)
306		log_err(1, "ISCSIDFAIL");
307}
308
309/*
310 * XXX: I CANT INTO LATIN
311 */
312static void
313capsicate(struct connection *conn)
314{
315	int error;
316	cap_rights_t rights;
317#ifdef ICL_KERNEL_PROXY
318	const unsigned long cmds[] = { ISCSIDCONNECT, ISCSIDSEND, ISCSIDRECEIVE,
319	    ISCSIDHANDOFF, ISCSIDFAIL, ISCSISADD, ISCSISREMOVE, ISCSISMODIFY };
320#else
321	const unsigned long cmds[] = { ISCSIDHANDOFF, ISCSIDFAIL, ISCSISADD,
322	    ISCSISREMOVE, ISCSISMODIFY };
323#endif
324
325	cap_rights_init(&rights, CAP_IOCTL);
326	error = cap_rights_limit(conn->conn_iscsi_fd, &rights);
327	if (error != 0 && errno != ENOSYS)
328		log_err(1, "cap_rights_limit");
329
330	error = cap_ioctls_limit(conn->conn_iscsi_fd, cmds,
331	    sizeof(cmds) / sizeof(cmds[0]));
332	if (error != 0 && errno != ENOSYS)
333		log_err(1, "cap_ioctls_limit");
334
335	error = cap_enter();
336	if (error != 0 && errno != ENOSYS)
337		log_err(1, "cap_enter");
338
339	if (cap_sandboxed())
340		log_debugx("Capsicum capability mode enabled");
341	else
342		log_warnx("Capsicum capability mode not supported");
343}
344
345bool
346timed_out(void)
347{
348
349	return (sigalrm_received);
350}
351
352static void
353sigalrm_handler(int dummy __unused)
354{
355	/*
356	 * It would be easiest to just log an error and exit.  We can't
357	 * do this, though, because log_errx() is not signal safe, since
358	 * it calls syslog(3).  Instead, set a flag checked by pdu_send()
359	 * and pdu_receive(), to call log_errx() there.  Should they fail
360	 * to notice, we'll exit here one second later.
361	 */
362	if (sigalrm_received) {
363		/*
364		 * Oh well.  Just give up and quit.
365		 */
366		_exit(2);
367	}
368
369	sigalrm_received = true;
370}
371
372static void
373set_timeout(int timeout)
374{
375	struct sigaction sa;
376	struct itimerval itv;
377	int error;
378
379	if (timeout <= 0) {
380		log_debugx("session timeout disabled");
381		return;
382	}
383
384	bzero(&sa, sizeof(sa));
385	sa.sa_handler = sigalrm_handler;
386	sigfillset(&sa.sa_mask);
387	error = sigaction(SIGALRM, &sa, NULL);
388	if (error != 0)
389		log_err(1, "sigaction");
390
391	/*
392	 * First SIGALRM will arive after conf_timeout seconds.
393	 * If we do nothing, another one will arrive a second later.
394	 */
395	bzero(&itv, sizeof(itv));
396	itv.it_interval.tv_sec = 1;
397	itv.it_value.tv_sec = timeout;
398
399	log_debugx("setting session timeout to %d seconds",
400	    timeout);
401	error = setitimer(ITIMER_REAL, &itv, NULL);
402	if (error != 0)
403		log_err(1, "setitimer");
404}
405
406static void
407sigchld_handler(int dummy __unused)
408{
409
410	/*
411	 * The only purpose of this handler is to make SIGCHLD
412	 * interrupt the ISCSIDWAIT ioctl(2), so we can call
413	 * wait_for_children().
414	 */
415}
416
417static void
418register_sigchld(void)
419{
420	struct sigaction sa;
421	int error;
422
423	bzero(&sa, sizeof(sa));
424	sa.sa_handler = sigchld_handler;
425	sigfillset(&sa.sa_mask);
426	error = sigaction(SIGCHLD, &sa, NULL);
427	if (error != 0)
428		log_err(1, "sigaction");
429
430}
431
432static void
433handle_request(int iscsi_fd, const struct iscsi_daemon_request *request, int timeout)
434{
435	struct connection *conn;
436
437	log_set_peer_addr(request->idr_conf.isc_target_addr);
438	if (request->idr_conf.isc_target[0] != '\0') {
439		log_set_peer_name(request->idr_conf.isc_target);
440		setproctitle("%s (%s)", request->idr_conf.isc_target_addr, request->idr_conf.isc_target);
441	} else {
442		setproctitle("%s", request->idr_conf.isc_target_addr);
443	}
444
445	conn = connection_new(request->idr_session_id, request->idr_isid,
446	    request->idr_tsih, &request->idr_conf, iscsi_fd);
447	set_timeout(timeout);
448	capsicate(conn);
449	login(conn);
450	if (conn->conn_conf.isc_discovery != 0)
451		discovery(conn);
452	else
453		handoff(conn);
454
455	log_debugx("nothing more to do; exiting");
456	exit (0);
457}
458
459static int
460wait_for_children(bool block)
461{
462	pid_t pid;
463	int status;
464	int num = 0;
465
466	for (;;) {
467		/*
468		 * If "block" is true, wait for at least one process.
469		 */
470		if (block && num == 0)
471			pid = wait4(-1, &status, 0, NULL);
472		else
473			pid = wait4(-1, &status, WNOHANG, NULL);
474		if (pid <= 0)
475			break;
476		if (WIFSIGNALED(status)) {
477			log_warnx("child process %d terminated with signal %d",
478			    pid, WTERMSIG(status));
479		} else if (WEXITSTATUS(status) != 0) {
480			log_warnx("child process %d terminated with exit status %d",
481			    pid, WEXITSTATUS(status));
482		} else {
483			log_debugx("child process %d terminated gracefully", pid);
484		}
485		num++;
486	}
487
488	return (num);
489}
490
491int
492main(int argc, char **argv)
493{
494	int ch, debug = 0, error, iscsi_fd, maxproc = 30, retval, saved_errno,
495	    timeout = 60;
496	bool dont_daemonize = false;
497	struct pidfh *pidfh;
498	pid_t pid, otherpid;
499	const char *pidfile_path = DEFAULT_PIDFILE;
500	struct iscsi_daemon_request request;
501
502	while ((ch = getopt(argc, argv, "P:dl:m:t:")) != -1) {
503		switch (ch) {
504		case 'P':
505			pidfile_path = optarg;
506			break;
507		case 'd':
508			dont_daemonize = true;
509			debug++;
510			break;
511		case 'l':
512			debug = atoi(optarg);
513			break;
514		case 'm':
515			maxproc = atoi(optarg);
516			break;
517		case 't':
518			timeout = atoi(optarg);
519			break;
520		case '?':
521		default:
522			usage();
523		}
524	}
525	argc -= optind;
526	if (argc != 0)
527		usage();
528
529	log_init(debug);
530
531	pidfh = pidfile_open(pidfile_path, 0600, &otherpid);
532	if (pidfh == NULL) {
533		if (errno == EEXIST)
534			log_errx(1, "daemon already running, pid: %jd.",
535			    (intmax_t)otherpid);
536		log_err(1, "cannot open or create pidfile \"%s\"",
537		    pidfile_path);
538	}
539
540	iscsi_fd = open(ISCSI_PATH, O_RDWR);
541	if (iscsi_fd < 0 && errno == ENOENT) {
542		saved_errno = errno;
543		retval = kldload("iscsi");
544		if (retval != -1)
545			iscsi_fd = open(ISCSI_PATH, O_RDWR);
546		else
547			errno = saved_errno;
548	}
549	if (iscsi_fd < 0)
550		log_err(1, "failed to open %s", ISCSI_PATH);
551
552	if (dont_daemonize == false) {
553		if (daemon(0, 0) == -1) {
554			log_warn("cannot daemonize");
555			pidfile_remove(pidfh);
556			exit(1);
557		}
558	}
559
560	pidfile_write(pidfh);
561
562	register_sigchld();
563
564	for (;;) {
565		log_debugx("waiting for request from the kernel");
566
567		memset(&request, 0, sizeof(request));
568		error = ioctl(iscsi_fd, ISCSIDWAIT, &request);
569		if (error != 0) {
570			if (errno == EINTR) {
571				nchildren -= wait_for_children(false);
572				assert(nchildren >= 0);
573				continue;
574			}
575
576			log_err(1, "ISCSIDWAIT");
577		}
578
579		if (dont_daemonize) {
580			log_debugx("not forking due to -d flag; "
581			    "will exit after servicing a single request");
582		} else {
583			nchildren -= wait_for_children(false);
584			assert(nchildren >= 0);
585
586			while (maxproc > 0 && nchildren >= maxproc) {
587				log_debugx("maxproc limit of %d child processes hit; "
588				    "waiting for child process to exit", maxproc);
589				nchildren -= wait_for_children(true);
590				assert(nchildren >= 0);
591			}
592			log_debugx("incoming connection; forking child process #%d",
593			    nchildren);
594			nchildren++;
595
596			pid = fork();
597			if (pid < 0)
598				log_err(1, "fork");
599			if (pid > 0)
600				continue;
601		}
602
603		pidfile_close(pidfh);
604		handle_request(iscsi_fd, &request, timeout);
605	}
606
607	return (0);
608}
609