1 /* $OpenBSD: pflogd.c,v 1.45 2007/06/06 14:11:26 henning Exp $ */
4 * Copyright (c) 2001 Theo de Raadt
5 * Copyright (c) 2001 Can Erkin Acar
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
12 * - Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * - Redistributions in binary form must reproduce the above
15 * copyright notice, this list of conditions and the following
16 * disclaimer in the documentation and/or other materials provided
17 * with the distribution.
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
22 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
23 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
24 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
25 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
26 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
27 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
29 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30 * POSSIBILITY OF SUCH DAMAGE.
33 #include <sys/types.h>
34 #include <sys/ioctl.h>
37 #include <sys/socket.h>
40 #include <machine/inttypes.h>
63 static int snaplen = DEF_SNAPLEN;
64 static int cur_snaplen = DEF_SNAPLEN;
66 volatile sig_atomic_t gotsig_close, gotsig_alrm, gotsig_hup;
68 const char *filename = PFLOGD_LOG_FILE;
69 const char *interface = PFLOGD_DEFAULT_IF;
72 char errbuf[PCAP_ERRBUF_SIZE];
75 unsigned int delay = FLUSH_DELAY;
77 char *copy_argv(char * const *);
78 void dump_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
79 void dump_packet_nobuf(u_char *, const struct pcap_pkthdr *, const u_char *);
80 int flush_buffer(FILE *);
81 int if_exists(char *);
83 void purge_buffer(void);
85 int scan_dump(FILE *, off_t);
87 void set_suspended(int);
93 static int try_reset_dump(int);
95 /* buffer must always be greater than snaplen */
96 static int bufpkt = 0; /* number of packets in buffer */
97 static size_t buflen = 0; /* allocated size of buffer */
98 static char *buffer = NULL; /* packet buffer */
99 static char *bufpos = NULL; /* position in buffer */
100 static size_t bufleft = 0; /* bytes left in buffer */
102 /* if error, stop logging but count dropped packets */
103 static int suspended = -1;
104 static long packets_dropped = 0;
113 setproctitle("[%s] -s %d -i %s -f %s",
114 suspended ? "suspended" : "running",
115 cur_snaplen, interface, filename);
119 copy_argv(char * const *argv)
127 for (n = 0; argv[n]; n++)
128 len += strlen(argv[n])+1;
136 strlcpy(buf, argv[0], len);
137 for (n = 1; argv[n]; n++) {
138 strlcat(buf, " ", len);
139 strlcat(buf, argv[n], len);
145 logmsg(int pri, const char *message, ...)
148 va_start(ap, message);
151 vfprintf(stderr, message, ap);
152 fprintf(stderr, "\n");
154 vsyslog(pri, message, ap);
161 fprintf(stderr, "usage: pflogd [-Dx] [-d delay] [-f filename]");
162 fprintf(stderr, " [-i interface] [-p pidfile]\n");
163 fprintf(stderr, " [-s snaplen] [expression]\n");
168 sig_close(int sig __unused)
174 sig_hup(int sig __unused)
180 sig_alrm(int sig __unused)
186 set_pcap_filter(void)
188 struct bpf_program bprog;
190 if (pcap_compile(hpcap, &bprog, filter, PCAP_OPT_FIL, 0) < 0)
191 logmsg(LOG_WARNING, "%s", pcap_geterr(hpcap));
193 if (pcap_setfilter(hpcap, &bprog) < 0)
194 logmsg(LOG_WARNING, "%s", pcap_geterr(hpcap));
195 pcap_freecode(&bprog);
200 if_exists(char *ifname)
204 struct if_data ifrdat;
206 if ((s = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
208 bzero(&ifr, sizeof(ifr));
209 if (strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)) >=
210 sizeof(ifr.ifr_name))
211 errx(1, "main ifr_name: strlcpy");
212 ifr.ifr_data = (caddr_t)&ifrdat;
213 if (ioctl(s, SIOCGIFDATA, (caddr_t)&ifr) == -1)
224 hpcap = pcap_open_live(interface, snaplen, 1, PCAP_TO_MS, errbuf);
226 logmsg(LOG_ERR, "Failed to initialize: %s", errbuf);
230 if (pcap_datalink(hpcap) != DLT_PFLOG) {
231 logmsg(LOG_ERR, "Invalid datalink type");
239 cur_snaplen = snaplen = pcap_snapshot(hpcap);
241 /* From contrib/pf/pflogd.c 1.5 FreeBSD: BPF locking is not
244 #ifndef __DragonFly__
246 if (ioctl(pcap_fileno(hpcap), BIOCLOCK) < 0) {
247 logmsg(LOG_ERR, "BIOCLOCK: %s", strerror(errno));
256 set_snaplen(int snap)
258 if (priv_set_snaplen(snap))
261 if (cur_snaplen > snap)
270 reset_dump(int nomove)
275 ret = try_reset_dump(nomove);
284 * tries to (re)open log file, nomove flag is used with -x switch
285 * returns 0: success, 1: retry (log moved), -1: error
288 try_reset_dump(int nomove)
290 struct pcap_file_header hdr;
305 * Basically reimplement pcap_dump_open() because it truncates
306 * files and duplicates headers and such.
308 fd = priv_open_log();
312 fp = fdopen(fd, "a+");
315 logmsg(LOG_ERR, "Error: %s: %s", filename, strerror(errno));
319 if (fstat(fileno(fp), &st) == -1) {
320 logmsg(LOG_ERR, "Error: %s: %s", filename, strerror(errno));
325 /* set FILE unbuffered, we do our own buffering */
326 if (setvbuf(fp, NULL, _IONBF, 0)) {
327 logmsg(LOG_ERR, "Failed to set output buffers");
332 #define TCPDUMP_MAGIC 0xa1b2c3d4
334 if (st.st_size == 0) {
335 if (snaplen != cur_snaplen) {
336 logmsg(LOG_NOTICE, "Using snaplen %d", snaplen);
337 if (set_snaplen(snaplen))
339 "Failed, using old settings");
341 hdr.magic = TCPDUMP_MAGIC;
342 hdr.version_major = PCAP_VERSION_MAJOR;
343 hdr.version_minor = PCAP_VERSION_MINOR;
344 hdr.thiszone = hpcap->tzoff;
345 hdr.snaplen = hpcap->snapshot;
347 hdr.linktype = hpcap->linktype;
349 if (fwrite((char *)&hdr, sizeof(hdr), 1, fp) != 1) {
353 } else if (scan_dump(fp, st.st_size)) {
355 if (nomove || priv_move_log()) {
357 "Invalid/incompatible log file, move it away");
372 scan_dump(FILE *fp, off_t size)
374 struct pcap_file_header hdr;
375 struct pcap_pkthdr ph;
379 * Must read the file, compare the header against our new
380 * options (in particular, snaplen) and adjust our options so
381 * that we generate a correct file. Furthermore, check the file
382 * for consistency so that we can append safely.
384 * XXX this may take a long time for large logs.
386 fseek(fp, 0L, SEEK_SET);
388 if (fread((char *)&hdr, sizeof(hdr), 1, fp) != 1) {
389 logmsg(LOG_ERR, "Short file header");
393 if (hdr.magic != TCPDUMP_MAGIC ||
394 hdr.version_major != PCAP_VERSION_MAJOR ||
395 hdr.version_minor != PCAP_VERSION_MINOR ||
396 (int)hdr.linktype != hpcap->linktype ||
397 hdr.snaplen > PFLOGD_MAXSNAPLEN) {
404 off_t len = fread((char *)&ph, 1, sizeof(ph), fp);
408 if (len != sizeof(ph))
410 if (ph.caplen > hdr.snaplen || ph.caplen > PFLOGD_MAXSNAPLEN)
412 pos += sizeof(ph) + ph.caplen;
415 fseek(fp, ph.caplen, SEEK_CUR);
421 if ((int)hdr.snaplen != cur_snaplen) {
423 "Existing file has different snaplen %u, using it",
425 if (set_snaplen(hdr.snaplen)) {
427 "Failed, using old settings, offset %llu",
428 (unsigned long long) size);
435 logmsg(LOG_ERR, "Corrupted log file.");
439 /* dump a packet directly to the stream, which is unbuffered */
441 dump_packet_nobuf(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
443 FILE *f = (FILE *)user;
450 if (fwrite(h, sizeof(*h), 1, f) != 1) {
451 off_t pos = ftello(f);
453 /* try to undo header to prevent corruption */
454 if ((size_t)pos < sizeof(*h) ||
455 ftruncate(fileno(f), pos - sizeof(*h))) {
456 logmsg(LOG_ERR, "Write failed, corrupted logfile!");
464 if (fwrite(sp, h->caplen, 1, f) != 1)
472 logmsg(LOG_ERR, "Logging suspended: fwrite: %s", strerror(errno));
476 flush_buffer(FILE *f)
479 int len = bufpos - buffer;
485 if (offset == (off_t)-1) {
487 logmsg(LOG_ERR, "Logging suspended: ftello: %s",
492 if (fwrite(buffer, len, 1, f) != 1) {
494 logmsg(LOG_ERR, "Logging suspended: fwrite: %s",
496 ftruncate(fileno(f), offset);
511 packets_dropped += bufpkt;
519 /* append packet to the buffer, flushing if necessary */
521 dump_packet(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
523 FILE *f = (FILE *)user;
524 size_t len = sizeof(*h) + h->caplen;
526 if (len < sizeof(*h) || h->caplen > (size_t)cur_snaplen) {
527 logmsg(LOG_NOTICE, "invalid size %zd (%u/%u), packet dropped",
528 len, cur_snaplen, snaplen);
541 if (flush_buffer(f)) {
547 dump_packet_nobuf(user, h, sp);
552 memcpy(bufpos, h, sizeof(*h));
553 memcpy(bufpos + sizeof(*h), sp, h->caplen);
563 main(int argc, char **argv)
565 struct pcap_stat pstat;
566 int ch, np, ret, Xflag = 0;
567 pcap_handler phandler = dump_packet;
568 const char *errstr = NULL;
573 /* Neither FreeBSD nor DFly have this; Max seems to think this may
574 * be a paranoid check. Comment it out:
575 closefrom(STDERR_FILENO + 1);
578 while ((ch = getopt(argc, argv, "Dxd:f:i:p:s:")) != -1) {
584 delay = strtonum(optarg, 5, 60*60, &errstr);
598 snaplen = strtonum(optarg, 0, PFLOGD_MAXSNAPLEN,
601 snaplen = DEF_SNAPLEN;
603 snaplen = PFLOGD_MAXSNAPLEN;
618 /* does interface exist */
619 if (!if_exists(__DECONST(char *, interface))) {
620 warn("Failed to initialize: %s", interface);
621 logmsg(LOG_ERR, "Failed to initialize: %s", interface);
622 logmsg(LOG_ERR, "Exiting, init failure");
627 openlog("pflogd", LOG_PID | LOG_CONS, LOG_DAEMON);
629 logmsg(LOG_WARNING, "Failed to become daemon: %s",
635 umask(S_IRWXG | S_IRWXO);
637 /* filter will be used by the privileged process */
639 filter = copy_argv(argv);
641 logmsg(LOG_NOTICE, "Failed to form filter expression");
644 /* initialize pcap before dropping privileges */
646 logmsg(LOG_ERR, "Exiting, init failure");
650 /* Privilege separation begins here */
652 logmsg(LOG_ERR, "unable to privsep");
656 setproctitle("[initializing]");
657 /* Process is now unprivileged and inside a chroot */
658 signal(SIGTERM, sig_close);
659 signal(SIGINT, sig_close);
660 signal(SIGQUIT, sig_close);
661 signal(SIGALRM, sig_alrm);
662 signal(SIGHUP, sig_hup);
665 buffer = malloc(PFLOGD_BUFSIZE);
667 if (buffer == NULL) {
668 logmsg(LOG_WARNING, "Failed to allocate output buffer");
669 phandler = dump_packet_nobuf;
671 bufleft = buflen = PFLOGD_BUFSIZE;
676 if (reset_dump(Xflag) < 0) {
680 logmsg(LOG_ERR, "Logging suspended: open error");
686 np = pcap_dispatch(hpcap, PCAP_NUM_PKTS,
687 phandler, (u_char *)dpcap);
689 if (!if_exists(__DECONST(char *, interface)) == -1) {
690 logmsg(LOG_NOTICE, "interface %s went away",
695 logmsg(LOG_NOTICE, "%s", pcap_geterr(hpcap));
703 "Logging suspended: open error");
719 logmsg(LOG_NOTICE, "Exiting");
726 if (pcap_stats(hpcap, &pstat) < 0)
727 logmsg(LOG_WARNING, "Reading stats: %s", pcap_geterr(hpcap));
730 "%u packets received, %u/%ld dropped (kernel/pflogd)",
731 pstat.ps_recv, pstat.ps_drop, packets_dropped);