F5OEO-tstools/pcap.c

221 wiersze
4.6 KiB
C

/* pcap.c */
/*
* Read pcap files.
*
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is the MPEG TS, PS and ES tools.
*
* The Initial Developer of the Original Code is Amino Communications Ltd.
* Portions created by the Initial Developer are Copyright (C) 2008
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Richard Watts, Kynesim <rrw@kynesim.co.uk>
*
* ***** END LICENSE BLOCK *****
*/
/* Both of these return 1 on success, 0 on EOF, <0 on error */
#include "pcap.h"
#include "misc_fns.h"
static int pcap_read_header(PCAP_reader_p ctx, pcap_hdr_t *out_hdr);
static int pcap_read_pktheader(PCAP_reader_p ctx, pcaprec_hdr_t *out_hdr);
int pcap_open(PCAP_reader_p *ctx_p, pcap_hdr_t *out_hdr,
const char *filename)
{
FILE *fptr = (filename ? fopen(filename, "rb") : stdin);
PCAP_reader_p ctx;
int rv;
(*ctx_p) = NULL;
if (!fptr)
{
// Couldn't open the file.
return -1;
}
ctx = (PCAP_reader_p)malloc(SIZEOF_PCAP_READER);
if (!ctx)
{
fclose(fptr);
// Out of memory.
return -2;
}
ctx->file = fptr;
rv = pcap_read_header(ctx, out_hdr);
if (rv != 1)
{
// Header read failed.
fclose(ctx->file);
free(ctx);
return -4;
}
(*ctx_p) = ctx;
return 0;
}
int pcap_read_next(PCAP_reader_p ctx, pcaprec_hdr_t *out_hdr,
uint8_t **out_data,
uint32_t *out_len)
{
int rv;
(*out_data) = NULL; (*out_len) = 0;
rv = pcap_read_pktheader(ctx, out_hdr);
if (rv != 1) { return rv; }
// Otherwise we now know how long our packet is ..
(*out_data) = (uint8_t *)malloc(out_hdr->incl_len);
if (!(*out_data))
{
// Out of memory.
return -3;
}
(*out_len) = out_hdr->incl_len;
rv = fread((*out_data), (*out_len), 1, ctx->file);
if (rv != 1)
{
free(*out_data); (*out_data) = NULL;
*out_len = 0;
if (feof(ctx->file))
{
// Ah. EOF.
return 0;
}
else
{
// Error. Curses.
return rv;
}
}
else if (rv == 1)
{
// Gotcha.
return 1;
}
return 0;
}
static int pcap_read_header(PCAP_reader_p ctx, pcap_hdr_t *hdr)
{
uint8_t hdr_val[SIZEOF_PCAP_HDR_ON_DISC];
int rv;
rv = fread(&hdr_val[0], SIZEOF_PCAP_HDR_ON_DISC, 1, ctx->file);
if (rv != 1)
{
if (feof(ctx->file))
{
return 0;
}
else
{
return PCAP_ERR_FILE_READ;
}
}
/* The magic number is 0xa1b2c3d4. If the writing
* machine was BE, the first byte will be a1 else d4
*/
if (hdr_val[0] == 0xa1)
{
// Big endian.
ctx->is_be = 1;
}
else if (hdr_val[0] == 0xd4)
{
// Little endian.
ctx->is_be = 0;
}
else
{
return PCAP_ERR_INVALID_MAGIC;
}
hdr->magic_number = (ctx->is_be ? uint_32_be(&hdr_val[0]) :
uint_32_le(&hdr_val[0]));
if (hdr->magic_number != 0xa1b2c3d4)
{
return PCAP_ERR_INVALID_MAGIC;
}
hdr->version_major = (ctx->is_be ? uint_16_be(&hdr_val[4]) :
uint_16_le(&hdr_val[4]));
hdr->version_minor = (ctx->is_be ? uint_16_be(&hdr_val[6]) :
uint_16_le(&hdr_val[6]));
hdr->thiszone = (int32_t)(ctx->is_be ? uint_32_be(&hdr_val[8]) :
uint_32_le(&hdr_val[8]));
hdr->sigfigs = (ctx->is_be ? uint_32_be(&hdr_val[12]) :
uint_32_le(&hdr_val[12]));
hdr->snaplen = (ctx->is_be ? uint_32_be(&hdr_val[16]) :
uint_32_le(&hdr_val[16]));
hdr->network = (ctx->is_be ? uint_32_be(&hdr_val[20]) :
uint_32_le(&hdr_val[20]));
return 1;
}
static int pcap_read_pktheader(PCAP_reader_p ctx, pcaprec_hdr_t *hdr)
{
uint8_t hdr_val[SIZEOF_PCAPREC_HDR_ON_DISC];
int rv;
rv = fread(&hdr_val[0], SIZEOF_PCAPREC_HDR_ON_DISC, 1, ctx->file);
if (rv != 1)
{
if (feof(ctx->file))
{
return 0;
}
else
{
return PCAP_ERR_FILE_READ;
}
}
hdr->ts_sec = (ctx->is_be ? uint_32_be(&hdr_val[0]) :
uint_32_le(&hdr_val[0]));
hdr->ts_usec = (ctx->is_be ? uint_32_be(&hdr_val[4]) :
uint_32_le(&hdr_val[4]));
hdr->incl_len = (ctx->is_be ? uint_32_be(&hdr_val[8]) :
uint_32_le(&hdr_val[8]));
hdr->orig_len = (ctx->is_be ? uint_32_be(&hdr_val[12]) :
uint_32_le(&hdr_val[12]));
return 1;
}
/* End file */