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epcap.h
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epcap.h
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/* Copyright (c) 2009-2012, Michael Santos <michael.santos@gmail.com>
* 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.
*
* Neither the name of the author nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* 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 HOLDER 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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <err.h>
#include <signal.h>
#include <fcntl.h>
#include <sys/select.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <pcap.h>
#if !defined(PCAP_NETMASK_UNKNOWN)
#define PCAP_NETMASK_UNKNOWN 0xffffffff
#endif
#define EPCAP_VERSION "0.03"
#define MAXBUFLEN 4096 /* Largest message accepted on stdin */
#define PKTLENHDR 2 /* 2 byte packet length header */
#define SNAPLEN 65535
#define PROMISC 1 /* true */
/* On Linux, 0 will block until the next packet is received.
* On BSD, 0 will block until the snaplen buffer is full.
*/
#define TIMEOUT 500 /* ms, 0 = block indefinitely */
#define EPCAP_FILTER "tcp and port 80"
#define PCAP_ERRBUF(x) do { \
if ((x) == NULL) \
errx(EXIT_FAILURE, "%s: %s", #x, errbuf); \
} while (0);
#define IS_NULL(x) do { \
if ((x) == NULL) \
errx(EXIT_FAILURE, "%s", #x); \
} while (0);
#define IS_FALSE(x) do { \
if ((x) != 0) \
errx(EXIT_FAILURE, "%s", #x); \
} while (0);
#define IS_LTZERO(x) do { \
if ((x) < 0) \
errx(EXIT_FAILURE, "%s", #x); \
} while (0);
#define VERBOSE(x, ...) do { \
if (ep->verbose >= x) { \
(void)fprintf (stderr, __VA_ARGS__); \
} \
} while (0)
extern char *__progname;
typedef struct {
pcap_t *p; /* pcap handle */
int promisc; /* promiscuous mode */
int rfmon; /* monitor mode */
int verbose; /* debugging messages */
int runasuser; /* if setuid, run as the calling user */
size_t snaplen; /* packet capture length */
u_int32_t timeout; /* capture timeout */
char *filt; /* packet filter */
char *dev; /* device to snoop */
char *user; /* run as unprivileged user */
char *group; /* run as unprivilted group */
char *chroot; /* chroot directory */
char *file; /* filename in case we read from pcap file */
} EPCAP_STATE;
int epcap_priv_drop(EPCAP_STATE *ep);
void epcap_priv_issetuid(EPCAP_STATE *ep);
int epcap_priv_rlimits(int nfd);