ninfod.c revision 313379eb6b9da55f7371adef39a92153a0707d4a 
1/* $USAGI: ninfod.c,v 1.34 2003-01-15 06:41:23 mk Exp $ */
2/*
3 * Copyright (C) 2002 USAGI/WIDE Project.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the project nor the names of its contributors
15 *    may be used to endorse or promote products derived from this software
16 *    without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30/*
31 * Author:
32 * 	YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
33 */
34
35#if HAVE_CONFIG_H
36#include "config.h"
37#endif
38
39#if HAVE_SYS_TYPES_H
40# include <sys/types.h>
41#endif
42#if STDC_HEADERS
43# include <stdio.h>
44# include <stdlib.h>
45# include <stddef.h>
46# include <stdarg.h>
47#else
48# if HAVE_STDLIB_H
49#  include <stdlib.h>
50# endif
51#endif
52
53#if HAVE_STRING_H
54# if !STDC_HEADERS && HAVE_MEMORY_H
55#  include <memory.h>
56# endif
57# include <string.h>
58#endif
59#if HAVE_STRINGS_H
60# include <strings.h>
61#endif
62#if HAVE_INTTYPES_H
63# include <inttypes.h>
64#else
65# if HAVE_STDINT_H
66#  include <stdint.h>
67# endif
68#endif
69#if HAVE_LIMITS_H
70# include <limits.h>
71#endif
72#if HAVE_UNISTD_H
73# include <unistd.h>
74#endif
75
76#ifdef TIME_WITH_SYS_TIME
77# include <sys/time.h>
78# include <time.h>
79#else
80# ifdef HAVE_SYS_TIME_H
81#  include <sys/time.h>
82# else
83#  include <time.h>
84# endif
85#endif
86
87#if HAVE_SYS_UIO_H
88#include <sys/uio.h>
89#endif
90
91#include <sys/socket.h>
92
93#if HAVE_NETINET_IN_H
94# include <netinet/in.h>
95#endif
96
97#if HAVE_NETINET_ICMP6_H
98# include <netinet/icmp6.h>
99#endif
100#ifndef HAVE_STRUCT_ICMP6_NODEINFO
101# include "icmp6_nodeinfo.h"
102#endif
103
104#if HAVE_NETDB_H
105# include <netdb.h>
106#endif
107#include <errno.h>
108
109#include <signal.h>
110
111#if HAVE_SYSLOG_H
112# include <syslog.h>
113#endif
114
115#if HAVE_PWD_H
116# include <pwd.h>
117#endif
118
119#if HAVE_SYS_CAPABILITY_H
120# include <sys/prctl.h>
121# include <sys/capability.h>
122#endif
123
124#include "ninfod.h"
125
126#ifndef offsetof
127# define offsetof(aggregate,member)	((size_t)&((aggregate *)0)->member)
128#endif
129
130/* --------- */
131/* ID */
132static char *RCSID __attribute__ ((unused)) = "$USAGI: ninfod.c,v 1.34 2003-01-15 06:41:23 mk Exp $";
133
134/* Variables */
135int sock;
136int daemonized;
137
138char *appname;
139static int opt_d = 0;	/* debug */
140static int opt_h = 0;	/* help */
141static char *opt_p = NINFOD_PIDFILE;	/* pidfile */
142static int got_signal = 0;	/* loop unless true */
143int opt_v = 0;		/* verbose */
144static uid_t opt_u;
145
146static int ipv6_pktinfo = IPV6_PKTINFO;
147
148/* --------- */
149#if ENABLE_DEBUG
150static const __inline__ char * log_level(int priority) {
151	switch(priority) {
152	case LOG_EMERG:		return "EMERG";
153	case LOG_ALERT:		return "ALERT";
154	case LOG_CRIT:		return "CRIT";
155	case LOG_ERR:		return "ERR";
156	case LOG_WARNING:	return "WARNING";
157	case LOG_NOTICE:	return "NOTICE";
158	case LOG_INFO:		return "INFO";
159	case LOG_DEBUG:		return "DEBUG";
160	default:		return "???";
161	}
162}
163
164void stderrlog(int pri, char *fmt, ...)
165{
166	va_list ap;
167	char ebuf[512];
168	char *buf;
169	size_t buflen;
170
171	va_start(ap, fmt);
172
173	for (buf = ebuf, buflen = sizeof(ebuf);
174	     buflen < SIZE_MAX / 2;
175	     free(buf != ebuf ? buf : NULL), buf = NULL, buflen *= 2) {
176		size_t rem;
177		size_t res;
178
179		buf = malloc(buflen);
180		if (!buf)
181			break;	/*XXX*/
182
183		rem = buflen;
184
185		res = snprintf(buf, rem, "[%s] ", log_level(pri));
186		if (res >= rem)
187			continue;
188		rem -= res;
189
190		res = vsnprintf(buf + res, rem, fmt, ap);
191
192		if (res >= rem)
193			continue;
194		break;
195	}
196
197	if (buf) {
198		fputs(buf, stderr);
199		free(buf != ebuf ? buf : NULL);
200	}
201
202	va_end(ap);
203}
204#endif
205
206/* --------- */
207static int __inline__ open_sock(void)
208{
209	return socket(PF_INET6, SOCK_RAW, IPPROTO_ICMPV6);
210}
211
212static int set_recvpktinfo(int sock)
213{
214	int on, ret;
215
216	on = 1;
217
218#if defined(IPV6_RECVPKTINFO)
219	ret = setsockopt(sock,
220			 IPPROTO_IPV6, IPV6_RECVPKTINFO,
221			 &on, sizeof(on));
222	if (!ret)
223		return 0;
224# if defined(IPV6_2292PKTINFO)
225	ret = setsockopt(sock,
226			 IPPROTO_IPV6, IPV6_2292PKTINFO,
227			 &on, sizeof(on));
228	if (!ret) {
229		ipv6_pktinfo = IPV6_2292PKTINFO;
230		return 0;
231	}
232
233	DEBUG(LOG_ERR, "setsockopt(IPV6_RECVPKTINFO/IPV6_2292PKTINFO): %s\n",
234	      strerror(errno));
235# else
236	DEBUG(LOG_ERR, "setsockopt(IPV6_RECVPKTINFO): %s\n",
237	      strerror(errno));
238# endif
239#else
240	ret = setsockopt(sock,
241			 IPPROTO_IPV6, IPV6_PKTINFO,
242			 &on, sizeof(on));
243	if (!ret)
244		return 0;
245
246	DEBUG(LOG_ERR, "setsockopt(IPV6_PKTINFO): %s\n",
247	      strerror(errno));
248#endif
249
250	return -1;
251}
252
253static int __inline__ init_sock(int sock)
254{
255	struct icmp6_filter filter;
256#if NEED_IPV6CHECKSUM
257	int i;
258
259	i = offsetof(struct icmp6_nodeinfo, ni_cksum);
260	if (setsockopt(sock,
261		       IPPROTO_IPV6, IPV6_CHECKSUM,
262		       &i, sizeof(i)) < 0) {
263		DEBUG(LOG_ERR, "setsockopt(IPV6_CHECKSUM): %s\n",
264		      strerror(errno));
265		return -1;
266	}
267#endif
268
269	ICMP6_FILTER_SETBLOCKALL(&filter);
270	ICMP6_FILTER_SETPASS(ICMP6_NI_QUERY, &filter);
271	if (setsockopt(sock,
272		       IPPROTO_ICMPV6, ICMP6_FILTER,
273		       &filter, sizeof(filter)) < 0) {
274		DEBUG(LOG_ERR, "setsockopt(ICMP6_FILTER): %s\n",
275		      strerror(errno));
276		return -1;
277	}
278
279	if (set_recvpktinfo(sock) < 0)
280		return -1;
281
282	return 0;
283}
284
285/* --------- */
286int ni_recv(struct packetcontext *p)
287{
288	int sock = p->sock;
289	struct iovec iov[1];
290	struct msghdr msgh;
291	char recvcbuf[CMSG_SPACE(sizeof(p->pktinfo))];
292	struct cmsghdr *cmsg;
293	int cc;
294
295	DEBUG(LOG_DEBUG, "%s()\n", __func__);
296
297	memset(&iov, 0, sizeof(iov));
298	iov[0].iov_base = p->query;
299	iov[0].iov_len = sizeof(p->query);
300
301	memset(&msgh, 0, sizeof(msgh));
302	msgh.msg_name = (struct sockaddr *)&p->addr;
303	msgh.msg_namelen = sizeof(p->addr);
304	msgh.msg_iov = iov;
305	msgh.msg_iovlen = 1;
306	msgh.msg_control = recvcbuf;
307	msgh.msg_controllen = sizeof(recvcbuf);
308
309	if ((cc = recvmsg(sock, &msgh, 0)) < 0)
310		return -1;
311
312	p->querylen = cc;
313	p->addrlen = msgh.msg_namelen;
314
315	for (cmsg = CMSG_FIRSTHDR(&msgh); cmsg;
316	     cmsg = CMSG_NXTHDR(&msgh, cmsg)) {
317		if (cmsg->cmsg_level == IPPROTO_IPV6 &&
318		    (cmsg->cmsg_type == IPV6_PKTINFO
319#if defined(IPV6_2292PKTINFO)
320		     || cmsg->cmsg_type == IPV6_2292PKTINFO
321#endif
322		    )) {
323			memcpy(&p->pktinfo, CMSG_DATA(cmsg), sizeof(p->pktinfo));
324			break;
325		}
326	}
327
328	return 0;
329}
330
331int ni_send(struct packetcontext *p)
332{
333	int sock = p->sock;
334	struct iovec iov[2];
335	char cbuf[CMSG_SPACE(sizeof(p->pktinfo))];
336	struct msghdr msgh;
337	struct cmsghdr *cmsg;
338	int cc;
339
340	DEBUG(LOG_DEBUG, "%s()\n", __func__);
341
342	memset(&iov, 0, sizeof(iov));
343	iov[0].iov_base = &p->reply;
344	iov[0].iov_len = sizeof(p->reply);
345	iov[1].iov_base = p->replydata;
346	iov[1].iov_len = p->replydatalen;
347
348	memset(&msgh, 0, sizeof(msgh));
349	msgh.msg_name = (struct sockaddr *)&p->addr;
350	msgh.msg_namelen = p->addrlen;
351	msgh.msg_iov = iov;
352	msgh.msg_iovlen = p->replydata ? 2 : 1;
353
354	msgh.msg_control = cbuf;
355	msgh.msg_controllen = sizeof(cbuf);
356
357	cmsg = CMSG_FIRSTHDR(&msgh);
358	cmsg->cmsg_level = IPPROTO_IPV6;
359	cmsg->cmsg_type = ipv6_pktinfo;
360	cmsg->cmsg_len = CMSG_LEN(sizeof(p->pktinfo));
361	memcpy(CMSG_DATA(cmsg), &p->pktinfo, sizeof(p->pktinfo));
362
363	msgh.msg_controllen = cmsg->cmsg_len;
364
365	if (p->delay) {
366#if HAVE_NANOSLEEP
367		struct timespec ts, rts;
368		int err = 0;
369
370		rts.tv_sec  = p->delay / 1000000;
371		rts.tv_nsec = (long)(p->delay % 1000000) * 1000;
372
373		do {
374			ts = rts;
375			err = nanosleep(&ts, &rts);
376		} while(err < 0);
377#else
378		usleep(p->delay);	/*XXX: signal*/
379#endif
380	}
381
382	cc = sendmsg(sock, &msgh, 0);
383	if (cc < 0)
384		DEBUG(LOG_DEBUG, "sendmsg(): %s\n", strerror(errno));
385
386	ni_free(p->replydata);
387	ni_free(p);
388
389	return cc;
390}
391
392/* --------- */
393static void sig_handler(int sig)
394{
395	if (!got_signal)
396		DEBUG(LOG_INFO, "singnal(%d) received, quitting.\n", sig);
397	got_signal = 1;
398}
399
400static void setup_sighandlers(void)
401{
402	struct sigaction act;
403	sigset_t smask;
404	sigemptyset(&smask);
405	sigaddset(&smask, SIGHUP);
406	sigaddset(&smask, SIGINT);
407	sigaddset(&smask, SIGQUIT);
408	sigaddset(&smask, SIGTERM);
409
410	memset(&act, 0, sizeof(act));
411	act.sa_handler = sig_handler;
412	act.sa_mask = smask;
413
414	sigaction(SIGHUP, &act, NULL);
415	sigaction(SIGINT, &act, NULL);
416	sigaction(SIGQUIT, &act, NULL);
417	sigaction(SIGTERM, &act, NULL);
418}
419
420static void set_logfile(void)
421{
422	setbuf(stderr, NULL);
423#if ENABLE_DEBUG
424	openlog(NINFOD, 0, LOG_USER);
425#endif
426}
427
428static void cleanup_pidfile(void)
429{
430	int err;
431
432	if (daemonized && opt_p) {
433		err = unlink(opt_p);
434		DEBUG(LOG_ERR, "failed to unlink file '%s' : %s\n",
435				opt_p, strerror(errno));
436	}
437}
438
439static FILE *fopen_excl(const char *file)
440{
441#ifndef __linux__
442	int fd;
443	FILE *fp;
444
445	fd = open(file, O_CREAT | O_RDWR | O_EXCL,
446		  S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
447	if (fd < 0)
448		return NULL;
449
450	return fdopen(file, "w+");
451#else
452	return fopen(file, "w+x");
453#endif
454}
455
456static void do_daemonize(void)
457{
458	FILE *fp = NULL;
459	pid_t pid;
460
461	if (opt_p) {
462		if (!access(opt_p, R_OK)) {
463			if ((fp = fopen(opt_p, "r"))) {
464				if (fscanf(fp, "%d", &pid) != 1) {
465					DEBUG(LOG_ERR, "pid file '%s' exists, but read failed.\n",
466					      opt_p);
467				} else {
468					DEBUG(LOG_ERR, "pid file '%s' exists : %d\n",
469					      opt_p, pid);
470				}
471				fclose(fp);
472				exit(1);
473			}
474		}
475
476		fp = fopen_excl(opt_p);
477		if (!fp) {
478			DEBUG(LOG_ERR, "failed to open file '%s': %s\n",
479			      opt_p, strerror(errno));
480			exit(1);
481		}
482	}
483
484	if (daemon(0, 0) < 0) {
485		DEBUG(LOG_ERR, "failed to daemon(): %s\n", strerror(errno));
486		unlink(opt_p);
487		exit(1);
488	}
489	daemonized = 1;
490
491	if (fp) {
492		fprintf(fp, "%d\n", getpid());
493		fclose(fp);
494	}
495}
496
497/* --------- */
498#ifdef HAVE_LIBCAP
499static const cap_value_t cap_net_raw = CAP_NET_RAW;
500static const cap_value_t cap_setuid =  CAP_SETUID;
501static cap_flag_value_t cap_ok;
502#else
503static uid_t euid;
504#endif
505
506static void limit_capabilities(void)
507{
508#ifdef HAVE_LIBCAP
509	cap_t cap_p, cap_cur_p;
510
511	cap_p = cap_init();
512	if (!cap_p) {
513		DEBUG(LOG_ERR, "cap_init: %s\n", strerror(errno));
514		exit(-1);
515	}
516
517	cap_cur_p = cap_get_proc();
518	if (!cap_cur_p) {
519		DEBUG(LOG_ERR, "cap_get_proc: %s\n", strerror(errno));
520		exit(-1);
521        }
522
523	/* net_raw + setuid / net_raw */
524	cap_get_flag(cap_cur_p, CAP_NET_RAW, CAP_PERMITTED, &cap_ok);
525	if (cap_ok != CAP_CLEAR) {
526		cap_set_flag(cap_p, CAP_PERMITTED, 1, &cap_net_raw, CAP_SET);
527		cap_set_flag(cap_p, CAP_EFFECTIVE, 1, &cap_net_raw, CAP_SET);
528	}
529
530	cap_get_flag(cap_cur_p, CAP_SETUID, CAP_PERMITTED, &cap_ok);
531	if (cap_ok != CAP_CLEAR)
532		cap_set_flag(cap_p, CAP_PERMITTED, 1, &cap_setuid, CAP_SET);
533
534	if (cap_set_proc(cap_p) < 0) {
535		DEBUG(LOG_ERR, "cap_set_proc: %s\n", strerror(errno));
536		if (errno != EPERM)
537			exit(-1);
538	}
539
540	if (prctl(PR_SET_KEEPCAPS, 1) < 0) {
541		DEBUG(LOG_ERR, "prctl: %s\n", strerror(errno));
542		exit(-1);
543	}
544
545	cap_free(cap_cur_p);
546	cap_free(cap_p);
547#else
548	euid = geteuid();
549#endif
550}
551
552static void drop_capabilities(void)
553{
554#ifdef HAVE_LIBCAP
555	cap_t cap_p;
556
557	cap_p = cap_init();
558	if (!cap_p) {
559		DEBUG(LOG_ERR, "cap_init: %s\n", strerror(errno));
560		exit(-1);
561	}
562
563	/* setuid / setuid */
564	if (cap_ok != CAP_CLEAR) {
565		cap_set_flag(cap_p, CAP_PERMITTED, 1, &cap_setuid, CAP_SET);
566		cap_set_flag(cap_p, CAP_EFFECTIVE, 1, &cap_setuid, CAP_SET);
567
568		if (cap_set_proc(cap_p) < 0) {
569			DEBUG(LOG_ERR, "cap_set_proc: %s\n", strerror(errno));
570			exit(-1);
571		}
572	}
573
574	if (seteuid(opt_u ? opt_u : getuid()) < 0) {
575		DEBUG(LOG_ERR, "setuid: %s\n", strerror(errno));
576		exit(-1);
577	}
578
579	if (prctl(PR_SET_KEEPCAPS, 0) < 0) {
580		DEBUG(LOG_ERR, "prctl: %s\n", strerror(errno));
581		exit(-1);
582	}
583
584	cap_clear(cap_p);
585	if (cap_set_proc(cap_p) < 0) {
586		DEBUG(LOG_ERR, "cap_set_proc: %s\n", strerror(errno));
587		exit(-1);
588	}
589
590	cap_free(cap_p);
591#else
592	if (setuid(getuid()) < 0) {
593		DEBUG(LOG_ERR, "setuid: %s\n", strerror(errno));
594		exit(-1);
595	}
596#endif
597}
598
599/* --------- */
600static void parse_args(int argc, char **argv)
601{
602	int c;
603	unsigned long val;
604	char *ep;
605
606	/* parse options */
607	while ((c = getopt(argc, argv, "dhvp:u:")) != -1) {
608		switch(c) {
609		case 'd':	/* debug */
610			opt_d = 1;
611			break;
612		case 'v':	/* verbose */
613			opt_v = 1;
614			break;
615		case 'p':
616			opt_p = optarg;
617			break;
618		case 'u':
619			val = strtoul(optarg, &ep, 10);
620			if (!optarg || *ep) {
621				struct passwd *pw = getpwnam(optarg);
622				if (!pw) {
623					DEBUG(LOG_ERR, "No such user: %s", optarg);
624					exit(1);
625				}
626				opt_u = pw->pw_uid;
627			} else
628				opt_u = val;
629			break;
630		case 'h':	/* help */
631		default:
632			opt_h = 1;
633			break;
634		}
635	}
636
637	argc -= optind;
638#if 0
639	argv += optind;
640#endif
641
642	if (argc)
643		opt_h = 1;
644}
645
646static void print_copying(void) {
647	fprintf(stderr,
648		"Node Information Daemon\n"
649		"Copyright (C)2002 USAGI/WIDE Project.  All Rights Reserved.\n"
650		"\n"
651	);
652}
653
654static void print_usage(void) {
655	fprintf(stderr,
656		"Usage: %s [-d] [-p pidfile] [-u user] [-h] [-v]\n\n",
657		appname
658	);
659}
660
661/* --------- */
662int main (int argc, char **argv)
663{
664	int sock_errno = 0;
665	int ret;
666
667	appname = argv[0];
668	set_logfile();
669
670	limit_capabilities();
671
672	sock = open_sock();
673	if (sock < 0)
674		sock_errno = errno;
675
676	parse_args(argc, argv);
677
678	drop_capabilities();
679
680	if (opt_h || opt_v)
681		print_copying();
682	if (opt_h) {
683		print_usage();
684		exit(1);
685	}
686
687	if (sock_errno) {
688		DEBUG(LOG_ERR, "socket: %s\n", strerror(sock_errno));
689		exit(1);
690	}
691
692	/* initialize */
693	if (init_sock(sock) < 0)
694		exit(1);
695
696	setup_sighandlers();
697	if (!opt_d)
698		do_daemonize();
699
700	init_core(1);
701
702	/* main loop */
703	while (!got_signal) {
704		struct packetcontext *p;
705		struct icmp6_hdr *icmph;
706#if ENABLE_DEBUG
707		char saddrbuf[NI_MAXHOST];
708		int gni;
709#endif
710
711		init_core(0);
712
713		p = ni_malloc(sizeof(*p));
714		if (!p) {
715			DEBUG(LOG_WARNING, "%s(): failed to allocate packet context; sleep 1 sec.\n",
716			      __func__);
717			sleep(1);
718			continue;
719		}
720
721		while (!got_signal) {
722			memset(p, 0, sizeof(*p));
723			p->sock = sock;
724
725			if (ni_recv(p) < 0) {
726				if (got_signal)
727					break;
728				if (errno == EAGAIN || errno == EINTR)
729					continue;
730				/* XXX: syslog */
731				continue;
732			}
733			break;
734		}
735
736#if ENABLE_DEBUG
737		gni = getnameinfo((struct sockaddr *)&p->addr,
738				  p->addrlen,
739				  saddrbuf, sizeof(saddrbuf),
740				  NULL, 0,
741				  NI_NUMERICHOST);
742		if (gni)
743			sprintf(saddrbuf, "???");
744#endif
745		init_core(0);
746
747		if (p->querylen < sizeof(struct icmp6_hdr)) {
748			ni_free(p);
749			DEBUG(LOG_WARNING, "Too short icmp message from %s\n", saddrbuf);
750			continue;
751		}
752
753		icmph = (struct icmp6_hdr *)p->query;
754
755		DEBUG(LOG_DEBUG,
756		      "type=%d, code=%d, cksum=0x%04x\n",
757		      icmph->icmp6_type, icmph->icmp6_code,
758		      ntohs(icmph->icmp6_cksum));
759
760		if (icmph->icmp6_type != ICMP6_NI_QUERY) {
761			DEBUG(LOG_WARNING,
762			      "Strange icmp type %d from %s\n",
763			      icmph->icmp6_type, saddrbuf);
764			ni_free(p);
765			continue;
766		}
767
768		pr_nodeinfo(p);	/* this frees p */
769	}
770
771	cleanup_pidfile();
772
773	exit(0);
774}
775
776