ffmpeg/libavformat/rtmpdigest.c

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/*
* RTMP network protocol
* Copyright (c) 2009 Konstantin Shishkov
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* RTMP protocol digest
*/
#include <stdint.h>
#include "libavutil/error.h"
#include "libavutil/hmac.h"
#include "rtmp.h"
int ff_rtmp_calc_digest(const uint8_t *src, int len, int gap,
const uint8_t *key, int keylen, uint8_t *dst)
{
AVHMAC *hmac;
hmac = av_hmac_alloc(AV_HMAC_SHA256);
if (!hmac)
return AVERROR(ENOMEM);
av_hmac_init(hmac, key, keylen);
if (gap <= 0) {
av_hmac_update(hmac, src, len);
} else { //skip 32 bytes used for storing digest
av_hmac_update(hmac, src, gap);
av_hmac_update(hmac, src + gap + 32, len - gap - 32);
}
av_hmac_final(hmac, dst, 32);
av_hmac_free(hmac);
return 0;
}
int ff_rtmp_calc_digest_pos(const uint8_t *buf, int off, int mod_val,
int add_val)
{
int i, digest_pos = 0;
for (i = 0; i < 4; i++)
digest_pos += buf[i + off];
digest_pos = digest_pos % mod_val + add_val;
return digest_pos;
}