FFmpeg
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
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
error code definitions
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:766
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
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions