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rtmpdigest.c
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1 /*
2  * RTMP network protocol
3  * Copyright (c) 2009 Konstantin Shishkov
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 /**
23  * @file
24  * RTMP protocol digest
25  */
26 
27 #include <stdint.h>
28 
29 #include "libavutil/error.h"
30 #include "libavutil/hmac.h"
31 
32 #include "rtmp.h"
33 
34 int ff_rtmp_calc_digest(const uint8_t *src, int len, int gap,
35  const uint8_t *key, int keylen, uint8_t *dst)
36 {
37  AVHMAC *hmac;
38 
40  if (!hmac)
41  return AVERROR(ENOMEM);
42 
43  av_hmac_init(hmac, key, keylen);
44  if (gap <= 0) {
45  av_hmac_update(hmac, src, len);
46  } else { //skip 32 bytes used for storing digest
47  av_hmac_update(hmac, src, gap);
48  av_hmac_update(hmac, src + gap + 32, len - gap - 32);
49  }
50  av_hmac_final(hmac, dst, 32);
51 
52  av_hmac_free(hmac);
53 
54  return 0;
55 }
56 
57 int ff_rtmp_calc_digest_pos(const uint8_t *buf, int off, int mod_val,
58  int add_val)
59 {
60  int i, digest_pos = 0;
61 
62  for (i = 0; i < 4; i++)
63  digest_pos += buf[i + off];
64  digest_pos = digest_pos % mod_val + add_val;
65 
66  return digest_pos;
67 }
AVHMAC * av_hmac_alloc(enum AVHMACType type)
Allocate an AVHMAC context.
Definition: hmac.c:72
const char * key
#define src
Definition: vp8dsp.c:254
uint8_t
void av_hmac_update(AVHMAC *c, const uint8_t *data, unsigned int len)
Hash data with the HMAC.
Definition: hmac.c:166
int ff_rtmp_calc_digest(const uint8_t *src, int len, int gap, const uint8_t *key, int keylen, uint8_t *dst)
Calculate HMAC-SHA2 digest for RTMP handshake packets.
Definition: rtmpdigest.c:34
error code definitions
#define AVERROR(e)
Definition: error.h:43
Definition: hmac.c:44
void av_hmac_init(AVHMAC *c, const uint8_t *key, unsigned int keylen)
Initialize an AVHMAC context with an authentication key.
Definition: hmac.c:145
void * buf
Definition: avisynth_c.h:690
int ff_rtmp_calc_digest_pos(const uint8_t *buf, int off, int mod_val, int add_val)
Calculate digest position for RTMP handshake packets.
Definition: rtmpdigest.c:57
int av_hmac_final(AVHMAC *c, uint8_t *out, unsigned int outlen)
Finish hashing and output the HMAC digest.
Definition: hmac.c:171
void av_hmac_free(AVHMAC *c)
Free an AVHMAC context.
Definition: hmac.c:137
int len