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ffmpeg-4.2.2/libavformat/rtmpdigest.c 1.79 KB
aac5773f   hucm   功能基本完成,接口待打磨
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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;
  }