iscsid.c revision 255665 
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: head/usr.sbin/iscsid/iscsid.c 255665 2013-09-18 08:37:14Z 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	idc = calloc(1, sizeof(*idc));
199	if (idc == NULL)
200		log_err(1, "calloc");
201
202	idc->idc_session_id = conn->conn_session_id;
203	if (conn->conn_conf.isc_iser)
204		idc->idc_iser = 1;
205	idc->idc_domain = to_ai->ai_family;
206	idc->idc_socktype = to_ai->ai_socktype;
207	idc->idc_protocol = to_ai->ai_protocol;
208	if (from_ai != NULL) {
209		idc->idc_from_addr = from_ai->ai_addr;
210		idc->idc_from_addrlen = from_ai->ai_addrlen;
211	}
212	idc->idc_to_addr = to_ai->ai_addr;
213	idc->idc_to_addrlen = to_ai->ai_addrlen;
214
215	log_debugx("connecting to %s using ICL kernel proxy", to_addr);
216	error = ioctl(iscsi_fd, ISCSIDCONNECT, idc);
217	if (error != 0) {
218		fail(conn, strerror(errno));
219		log_err(1, "failed to connect to %s using ICL kernel proxy",
220		    to_addr);
221	}
222
223#else /* !ICL_KERNEL_PROXY */
224
225	if (conn->conn_conf.isc_iser) {
226		fail(conn, "iSER not supported");
227		log_errx(1, "iscsid(8) compiled without ICL_KERNEL_PROXY "
228		    "does not support iSER");
229	}
230
231	conn->conn_socket = socket(to_ai->ai_family, to_ai->ai_socktype,
232	    to_ai->ai_protocol);
233	if (conn->conn_socket < 0) {
234		fail(conn, strerror(errno));
235		log_err(1, "failed to create socket for %s", from_addr);
236	}
237	if (from_ai != NULL) {
238		error = bind(conn->conn_socket, from_ai->ai_addr,
239		    from_ai->ai_addrlen);
240		if (error != 0) {
241			fail(conn, strerror(errno));
242			log_err(1, "failed to bind to %s", from_addr);
243		}
244	}
245	log_debugx("connecting to %s", to_addr);
246	error = connect(conn->conn_socket, to_ai->ai_addr, to_ai->ai_addrlen);
247	if (error != 0) {
248		fail(conn, strerror(errno));
249		log_err(1, "failed to connect to %s", to_addr);
250	}
251
252#endif /* !ICL_KERNEL_PROXY */
253
254	return (conn);
255}
256
257static void
258handoff(struct connection *conn)
259{
260	struct iscsi_daemon_handoff *idh;
261	int error;
262
263	log_debugx("handing off connection to the kernel");
264
265	idh = calloc(1, sizeof(*idh));
266	if (idh == NULL)
267		log_err(1, "calloc");
268	idh->idh_session_id = conn->conn_session_id;
269#ifndef ICL_KERNEL_PROXY
270	idh->idh_socket = conn->conn_socket;
271#endif
272	strlcpy(idh->idh_target_alias, conn->conn_target_alias,
273	    sizeof(idh->idh_target_alias));
274	memcpy(idh->idh_isid, conn->conn_isid, sizeof(idh->idh_isid));
275	idh->idh_statsn = conn->conn_statsn;
276	idh->idh_header_digest = conn->conn_header_digest;
277	idh->idh_data_digest = conn->conn_data_digest;
278	idh->idh_initial_r2t = conn->conn_initial_r2t;
279	idh->idh_immediate_data = conn->conn_immediate_data;
280	idh->idh_max_data_segment_length = conn->conn_max_data_segment_length;
281	idh->idh_max_burst_length = conn->conn_max_burst_length;
282	idh->idh_first_burst_length = conn->conn_first_burst_length;
283
284	error = ioctl(conn->conn_iscsi_fd, ISCSIDHANDOFF, idh);
285	if (error != 0)
286		log_err(1, "ISCSIDHANDOFF");
287}
288
289void
290fail(const struct connection *conn, const char *reason)
291{
292	struct iscsi_daemon_fail *idf;
293	int error;
294
295	idf = calloc(1, sizeof(*idf));
296	if (idf == NULL)
297		log_err(1, "calloc");
298
299	idf->idf_session_id = conn->conn_session_id;
300	strlcpy(idf->idf_reason, reason, sizeof(idf->idf_reason));
301
302	error = ioctl(conn->conn_iscsi_fd, ISCSIDFAIL, idf);
303	if (error != 0)
304		log_err(1, "ISCSIDFAIL");
305}
306
307/*
308 * XXX: I CANT INTO LATIN
309 */
310static void
311capsicate(struct connection *conn)
312{
313	int error;
314	cap_rights_t rights;
315#ifdef ICL_KERNEL_PROXY
316	const unsigned long cmds[] = { ISCSIDCONNECT, ISCSIDSEND, ISCSIDRECEIVE,
317	    ISCSIDHANDOFF, ISCSIDFAIL, ISCSISADD, ISCSISREMOVE };
318#else
319	const unsigned long cmds[] = { ISCSIDHANDOFF, ISCSIDFAIL, ISCSISADD,
320	    ISCSISREMOVE };
321#endif
322
323	cap_rights_init(&rights, CAP_IOCTL);
324	error = cap_rights_limit(conn->conn_iscsi_fd, &rights);
325	if (error != 0 && errno != ENOSYS)
326		log_err(1, "cap_rights_limit");
327
328	error = cap_ioctls_limit(conn->conn_iscsi_fd, cmds,
329	    sizeof(cmds) / sizeof(cmds[0]));
330	if (error != 0 && errno != ENOSYS)
331		log_err(1, "cap_ioctls_limit");
332
333	error = cap_enter();
334	if (error != 0 && errno != ENOSYS)
335		log_err(1, "cap_enter");
336
337	if (cap_sandboxed())
338		log_debugx("Capsicum capability mode enabled");
339	else
340		log_warnx("Capsicum capability mode not supported");
341}
342
343bool
344timed_out(void)
345{
346
347	return (sigalrm_received);
348}
349
350static void
351sigalrm_handler(int dummy __unused)
352{
353	/*
354	 * It would be easiest to just log an error and exit.  We can't
355	 * do this, though, because log_errx() is not signal safe, since
356	 * it calls syslog(3).  Instead, set a flag checked by pdu_send()
357	 * and pdu_receive(), to call log_errx() there.  Should they fail
358	 * to notice, we'll exit here one second later.
359	 */
360	if (sigalrm_received) {
361		/*
362		 * Oh well.  Just give up and quit.
363		 */
364		_exit(2);
365	}
366
367	sigalrm_received = true;
368}
369
370static void
371set_timeout(int timeout)
372{
373	struct sigaction sa;
374	struct itimerval itv;
375	int error;
376
377	if (timeout <= 0) {
378		log_debugx("session timeout disabled");
379		return;
380	}
381
382	bzero(&sa, sizeof(sa));
383	sa.sa_handler = sigalrm_handler;
384	sigfillset(&sa.sa_mask);
385	error = sigaction(SIGALRM, &sa, NULL);
386	if (error != 0)
387		log_err(1, "sigaction");
388
389	/*
390	 * First SIGALRM will arive after conf_timeout seconds.
391	 * If we do nothing, another one will arrive a second later.
392	 */
393	bzero(&itv, sizeof(itv));
394	itv.it_interval.tv_sec = 1;
395	itv.it_value.tv_sec = timeout;
396
397	log_debugx("setting session timeout to %d seconds",
398	    timeout);
399	error = setitimer(ITIMER_REAL, &itv, NULL);
400	if (error != 0)
401		log_err(1, "setitimer");
402}
403
404static void
405handle_request(int iscsi_fd, struct iscsi_daemon_request *request, int timeout)
406{
407	struct connection *conn;
408
409	log_set_peer_addr(request->idr_conf.isc_target_addr);
410	if (request->idr_conf.isc_target[0] != '\0') {
411		log_set_peer_name(request->idr_conf.isc_target);
412		setproctitle("%s (%s)", request->idr_conf.isc_target_addr, request->idr_conf.isc_target);
413	} else {
414		setproctitle("%s", request->idr_conf.isc_target_addr);
415	}
416
417	conn = connection_new(request->idr_session_id, &request->idr_conf, iscsi_fd);
418	set_timeout(timeout);
419	capsicate(conn);
420	login(conn);
421	if (conn->conn_conf.isc_discovery != 0)
422		discovery(conn);
423	else
424		handoff(conn);
425
426	log_debugx("nothing more to do; exiting");
427	exit (0);
428}
429
430static int
431wait_for_children(bool block)
432{
433	pid_t pid;
434	int status;
435	int num = 0;
436
437	for (;;) {
438		/*
439		 * If "block" is true, wait for at least one process.
440		 */
441		if (block && num == 0)
442			pid = wait4(-1, &status, 0, NULL);
443		else
444			pid = wait4(-1, &status, WNOHANG, NULL);
445		if (pid <= 0)
446			break;
447		if (WIFSIGNALED(status)) {
448			log_warnx("child process %d terminated with signal %d",
449			    pid, WTERMSIG(status));
450		} else if (WEXITSTATUS(status) != 0) {
451			log_warnx("child process %d terminated with exit status %d",
452			    pid, WEXITSTATUS(status));
453		} else {
454			log_debugx("child process %d terminated gracefully", pid);
455		}
456		num++;
457	}
458
459	return (num);
460}
461
462int
463main(int argc, char **argv)
464{
465	int ch, debug = 0, error, iscsi_fd, maxproc = 30, retval, saved_errno,
466	    timeout = 60;
467	bool dont_daemonize = false;
468	struct pidfh *pidfh;
469	pid_t pid, otherpid;
470	const char *pidfile_path = DEFAULT_PIDFILE;
471	struct iscsi_daemon_request *request;
472
473	while ((ch = getopt(argc, argv, "P:dl:m:t:")) != -1) {
474		switch (ch) {
475		case 'P':
476			pidfile_path = optarg;
477			break;
478		case 'd':
479			dont_daemonize = true;
480			debug++;
481			break;
482		case 'l':
483			debug = atoi(optarg);
484			break;
485		case 'm':
486			maxproc = atoi(optarg);
487			break;
488		case 't':
489			timeout = atoi(optarg);
490			break;
491		case '?':
492		default:
493			usage();
494		}
495	}
496	argc -= optind;
497	if (argc != 0)
498		usage();
499
500	log_init(debug);
501
502	pidfh = pidfile_open(pidfile_path, 0600, &otherpid);
503	if (pidfh == NULL) {
504		if (errno == EEXIST)
505			log_errx(1, "daemon already running, pid: %jd.",
506			    (intmax_t)otherpid);
507		log_err(1, "cannot open or create pidfile \"%s\"",
508		    pidfile_path);
509	}
510
511	iscsi_fd = open(ISCSI_PATH, O_RDWR);
512	if (iscsi_fd < 0 && errno == ENOENT) {
513		saved_errno = errno;
514		retval = kldload("iscsi");
515		if (retval != -1)
516			iscsi_fd = open(ISCSI_PATH, O_RDWR);
517		else
518			errno = saved_errno;
519	}
520	if (iscsi_fd < 0)
521		log_err(1, "failed to open %s", ISCSI_PATH);
522
523	if (dont_daemonize == false) {
524		if (daemon(0, 0) == -1) {
525			log_warn("cannot daemonize");
526			pidfile_remove(pidfh);
527			exit(1);
528		}
529	}
530
531	pidfile_write(pidfh);
532
533	for (;;) {
534		log_debugx("waiting for request from the kernel");
535
536		request = calloc(1, sizeof(*request));
537		if (request == NULL)
538			log_err(1, "calloc");
539
540		error = ioctl(iscsi_fd, ISCSIDWAIT, request);
541		if (error != 0) {
542			if (errno == EINTR) {
543				nchildren -= wait_for_children(false);
544				assert(nchildren >= 0);
545				continue;
546			}
547
548			log_err(1, "ISCSIDWAIT");
549		}
550
551		if (dont_daemonize) {
552			log_debugx("not forking due to -d flag; "
553			    "will exit after servicing a single request");
554		} else {
555			nchildren -= wait_for_children(false);
556			assert(nchildren >= 0);
557
558			while (maxproc > 0 && nchildren >= maxproc) {
559				log_debugx("maxproc limit of %d child processes hit; "
560				    "waiting for child process to exit", maxproc);
561				nchildren -= wait_for_children(true);
562				assert(nchildren >= 0);
563			}
564			log_debugx("incoming connection; forking child process #%d",
565			    nchildren);
566			nchildren++;
567
568			pid = fork();
569			if (pid < 0)
570				log_err(1, "fork");
571			if (pid > 0)
572				continue;
573		}
574
575		pidfile_close(pidfh);
576		handle_request(iscsi_fd, request, timeout);
577	}
578
579	return (0);
580}
581