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/* ipv4.c */
/*
* Routines for dissecting ipv4
*
*
* ***** 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 *****
*/
#include <stdio.h>
#include <stdlib.h>
#include "ipv4.h"
#include "misc_fns.h"
#include <string.h>
int ipv4_from_payload(const uint8_t *data,
const uint32_t len,
ipv4_header_t *out_hdr,
uint32_t *out_st,
uint32_t *out_len)
{
uint32_t cur_field;
// Min length of an ipv4 header is 20 bytes (5 words)
if (len < 20)
{
return IPV4_ERR_PKT_TOO_SHORT;
}
// Field 0
cur_field = uint_32_be(&data[0]);
out_hdr->version = (cur_field >> 28)&0xf;
out_hdr->hdr_length = (cur_field >> 24)& 0xf;
out_hdr->serv_type = (cur_field >> 16) & 0xff;
out_hdr->length = (cur_field) & 0xffff;
// Field 1
cur_field = uint_32_be(&data[4]);
out_hdr->ident = (cur_field >> 16) & 0xffff;
out_hdr->flags = (cur_field >> 14) & 3;
out_hdr->frag_offset = (cur_field & 0x3fff);
// Field 2
cur_field = uint_32_be(&data[8]);
out_hdr->ttl = (cur_field >> 24) & 0xff;
out_hdr->proto = (cur_field >> 16) & 0xff;
out_hdr->csum = (cur_field) & 0xffff;
// Field 3 - src address.
out_hdr->src_addr = uint_32_be(&data[12]);
// Field 4 - dest address.
out_hdr->dest_addr = uint_32_be(&data[16]);
// Now the data ..
(*out_st) = (out_hdr->hdr_length << 2);
(*out_len) = len - (out_hdr->hdr_length << 2);
return 0;
}
int ipv4_udp_from_payload(const uint8_t *data,
const uint32_t len,
ipv4_udp_header_t *out_hdr,
uint32_t *out_st,
uint32_t *out_len)
{
uint32_t cur_field;
// UDP headers are 8 bytes long.
if (len < 8)
{
return IPV4_ERR_PKT_TOO_SHORT;
}
cur_field = uint_32_be(&data[0]);
out_hdr->source_port = (cur_field >> 16)&0xffff;
out_hdr->dest_port = (cur_field) & 0xffff;
cur_field = uint_32_be(&data[4]);
out_hdr->length = (cur_field >> 16) & 0xffff;
out_hdr->csum = (cur_field) &0xffff;
(*out_st) = 8;
(*out_len) = len - 8;
return 0;
}
/* End file */
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