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/* $OpenBSD: pflogd.c,v 1.19 2003/04/23 22:44:53 deraadt Exp $ */
/*
* Copyright (c) 2001 Theo de Raadt
* Copyright (c) 2001 Can Erkin Acar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/types.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <pcap-int.h>
#include <pcap.h>
#include <syslog.h>
#include <signal.h>
#include <errno.h>
#include <stdarg.h>
#include <fcntl.h>
#include <util.h>
#define DEF_SNAPLEN 96 /* default plus allow for larger header of pflog */
#define PCAP_TO_MS 500 /* pcap read timeout (ms) */
#define PCAP_NUM_PKTS 1000 /* max number of packets to process at each loop */
#define PCAP_OPT_FIL 0 /* filter optimization */
#define FLUSH_DELAY 60 /* flush delay */
#define PFLOGD_LOG_FILE "/var/log/pflog"
#define PFLOGD_DEFAULT_IF "pflog0"
pcap_t *hpcap;
pcap_dumper_t *dpcap;
int Debug = 0;
int snaplen = DEF_SNAPLEN;
volatile sig_atomic_t gotsig_close, gotsig_alrm, gotsig_hup;
char *filename = PFLOGD_LOG_FILE;
char *interface = PFLOGD_DEFAULT_IF;
char *filter = NULL;
char errbuf[PCAP_ERRBUF_SIZE];
int log_debug = 0;
unsigned int delay = FLUSH_DELAY;
char *copy_argv(char * const *argv);
int init_pcap(void);
void logmsg(int priority, const char *message, ...);
int reset_dump(void);
void sig_alrm(int);
void sig_close(int);
void sig_hup(int);
void usage(void);
char *
copy_argv(char * const *argv)
{
size_t len = 0, n;
char *buf;
if (argv == NULL)
return (NULL);
for (n = 0; argv[n]; n++)
len += strlen(argv[n])+1;
if (len == 0)
return (NULL);
buf = malloc(len);
if (buf == NULL)
return (NULL);
strlcpy(buf, argv[0], len);
for (n = 1; argv[n]; n++) {
strlcat(buf, " ", len);
strlcat(buf, argv[n], len);
}
return (buf);
}
void
logmsg(int pri, const char *message, ...)
{
va_list ap;
va_start(ap, message);
if (log_debug) {
vfprintf(stderr, message, ap);
fprintf(stderr, "\n");
} else
vsyslog(pri, message, ap);
va_end(ap);
}
__dead void
usage(void)
{
fprintf(stderr, "usage: pflogd [-D] [-d delay] [-f filename] ");
fprintf(stderr, "[-s snaplen] [expression]\n");
exit(1);
}
void
sig_close(int sig)
{
gotsig_close = 1;
}
void
sig_hup(int sig)
{
gotsig_hup = 1;
}
void
sig_alrm(int sig)
{
gotsig_alrm = 1;
}
int
init_pcap(void)
{
struct bpf_program bprog;
pcap_t *oldhpcap = hpcap;
hpcap = pcap_open_live(interface, snaplen, 1, PCAP_TO_MS, errbuf);
if (hpcap == NULL) {
logmsg(LOG_ERR, "Failed to initialize: %s", errbuf);
hpcap = oldhpcap;
return (-1);
}
if (pcap_compile(hpcap, &bprog, filter, PCAP_OPT_FIL, 0) < 0)
logmsg(LOG_WARNING, "%s", pcap_geterr(hpcap));
else if (pcap_setfilter(hpcap, &bprog) < 0)
logmsg(LOG_WARNING, "%s", pcap_geterr(hpcap));
if (filter != NULL)
free(filter);
if (pcap_datalink(hpcap) != DLT_PFLOG) {
logmsg(LOG_ERR, "Invalid datalink type");
pcap_close(hpcap);
hpcap = oldhpcap;
return (-1);
}
if (oldhpcap)
pcap_close(oldhpcap);
snaplen = pcap_snapshot(hpcap);
return (0);
}
int
reset_dump(void)
{
struct pcap_file_header hdr;
struct stat st;
int tmpsnap;
FILE *fp;
if (hpcap == NULL)
return (1);
if (dpcap) {
pcap_dump_close(dpcap);
dpcap = 0;
}
/*
* Basically reimpliment pcap_dump_open() because it truncates
* files and duplicates headers and such.
*/
fp = fopen(filename, "a+");
if (fp == NULL) {
snprintf(hpcap->errbuf, PCAP_ERRBUF_SIZE, "%s: %s",
filename, pcap_strerror(errno));
logmsg(LOG_ERR, "Error: %s", pcap_geterr(hpcap));
return (1);
}
if (fstat(fileno(fp), &st) == -1) {
snprintf(hpcap->errbuf, PCAP_ERRBUF_SIZE, "%s: %s",
filename, pcap_strerror(errno));
logmsg(LOG_ERR, "Error: %s", pcap_geterr(hpcap));
return (1);
}
dpcap = (pcap_dumper_t *)fp;
#define TCPDUMP_MAGIC 0xa1b2c3d4
if (st.st_size == 0) {
if (snaplen != pcap_snapshot(hpcap)) {
logmsg(LOG_NOTICE, "Using snaplen %d", snaplen);
if (init_pcap()) {
logmsg(LOG_ERR, "Failed to initialize");
if (hpcap == NULL) return (-1);
logmsg(LOG_NOTICE, "Using old settings");
}
}
hdr.magic = TCPDUMP_MAGIC;
hdr.version_major = PCAP_VERSION_MAJOR;
hdr.version_minor = PCAP_VERSION_MINOR;
hdr.thiszone = hpcap->tzoff;
hdr.snaplen = hpcap->snapshot;
hdr.sigfigs = 0;
hdr.linktype = hpcap->linktype;
if (fwrite((char *)&hdr, sizeof(hdr), 1, fp) != 1) {
dpcap = NULL;
fclose(fp);
return (-1);
}
return (0);
}
/*
* XXX Must read the file, compare the header against our new
* options (in particular, snaplen) and adjust our options so
* that we generate a correct file.
*/
(void) fseek(fp, 0L, SEEK_SET);
if (fread((char *)&hdr, sizeof(hdr), 1, fp) == 1) {
if (hdr.magic == TCPDUMP_MAGIC &&
hdr.version_major == PCAP_VERSION_MAJOR &&
hdr.version_minor == PCAP_VERSION_MINOR &&
hdr.snaplen != snaplen) {
logmsg(LOG_WARNING,
"Existing file specifies a snaplen of %u, using it",
hdr.snaplen);
tmpsnap = snaplen;
snaplen = hdr.snaplen;
if (init_pcap()) {
logmsg(LOG_ERR, "Failed to re-initialize");
if (hpcap == 0)
return (-1);
logmsg(LOG_NOTICE,
"Using old settings, offset: %llu",
(unsigned long long)st.st_size);
}
snaplen = tmpsnap;
}
}
(void) fseek(fp, 0L, SEEK_END);
return (0);
}
int
main(int argc, char **argv)
{
struct pcap_stat pstat;
int ch, np;
while ((ch = getopt(argc, argv, "Dd:s:f:")) != -1) {
switch (ch) {
case 'D':
Debug = 1;
break;
case 'd':
delay = atoi(optarg);
if (delay < 5 || delay > 60*60)
usage();
break;
case 'f':
filename = optarg;
break;
case 's':
snaplen = atoi(optarg);
if (snaplen <= 0)
snaplen = DEF_SNAPLEN;
break;
default:
usage();
}
}
log_debug = Debug;
argc -= optind;
argv += optind;
if (!Debug) {
openlog("pflogd", LOG_PID | LOG_CONS, LOG_DAEMON);
if (daemon(0, 0)) {
logmsg(LOG_WARNING, "Failed to become daemon: %s",
strerror(errno));
}
pidfile(NULL);
}
(void)umask(S_IRWXG | S_IRWXO);
signal(SIGTERM, sig_close);
signal(SIGINT, sig_close);
signal(SIGQUIT, sig_close);
signal(SIGALRM, sig_alrm);
signal(SIGHUP, sig_hup);
alarm(delay);
if (argc) {
filter = copy_argv(argv);
if (filter == NULL)
logmsg(LOG_NOTICE, "Failed to form filter expression");
}
if (init_pcap()) {
logmsg(LOG_ERR, "Exiting, init failure");
exit(1);
}
if (reset_dump()) {
logmsg(LOG_ERR, "Failed to open log file %s", filename);
pcap_close(hpcap);
exit(1);
}
while (1) {
np = pcap_dispatch(hpcap, PCAP_NUM_PKTS, pcap_dump, (u_char *)dpcap);
if (np < 0)
logmsg(LOG_NOTICE, "%s", pcap_geterr(hpcap));
if (gotsig_close)
break;
if (gotsig_hup) {
if (reset_dump()) {
logmsg(LOG_ERR, "Failed to open log file!");
break;
}
logmsg(LOG_NOTICE, "Reopened logfile");
gotsig_hup = 0;
}
if (gotsig_alrm) {
/* XXX pcap_dumper is an incomplete type which libpcap
* casts to a FILE* currently. For now it is safe to
* make the same assumption, however this may change
* in the future.
*/
if (dpcap) {
if (fflush((FILE *)dpcap) == EOF) {
break;
}
}
gotsig_alrm = 0;
alarm(delay);
}
}
logmsg(LOG_NOTICE, "Exiting due to signal");
if (dpcap)
pcap_dump_close(dpcap);
if (pcap_stats(hpcap, &pstat) < 0)
logmsg(LOG_WARNING, "Reading stats: %s", pcap_geterr(hpcap));
else
logmsg(LOG_NOTICE, "%u packets received, %u dropped",
pstat.ps_recv, pstat.ps_drop);
pcap_close(hpcap);
if (!Debug)
closelog();
return (0);
}
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