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ffmpeg / libavformat / mms.c @ c46000c1

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/*
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 * MMS protocol common definitions.
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 * Copyright (c) 2006,2007 Ryan Martell
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 * Copyright (c) 2007 Bj?rn Axelsson
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 * Copyright (c) 2010 Zhentan Feng <spyfeng at gmail dot com>
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include "mms.h"
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#include "asf.h"
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#include "libavutil/intreadwrite.h"
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int ff_mms_read_header(MMSContext *mms, uint8_t *buf, const int size)
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{
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    char *pos;
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    int size_to_copy;
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    int remaining_size = mms->asf_header_size - mms->asf_header_read_size;
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    size_to_copy = FFMIN(size, remaining_size);
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    pos = mms->asf_header + mms->asf_header_read_size;
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    memcpy(buf, pos, size_to_copy);
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    if (mms->asf_header_read_size == mms->asf_header_size) {
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        av_freep(&mms->asf_header); // which contains asf header
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    }
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    mms->asf_header_read_size += size_to_copy;
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    return size_to_copy;
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}
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int ff_mms_read_data(MMSContext *mms, uint8_t *buf, const int size)
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{
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    int read_size;
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    read_size = FFMIN(size, mms->remaining_in_len);
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    memcpy(buf, mms->read_in_ptr, read_size);
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    mms->remaining_in_len -= read_size;
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    mms->read_in_ptr      += read_size;
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    return read_size;
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}
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int ff_mms_asf_header_parser(MMSContext *mms)
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{
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    uint8_t *p = mms->asf_header;
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    uint8_t *end;
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    int flags, stream_id;
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    mms->stream_num = 0;
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    if (mms->asf_header_size < sizeof(ff_asf_guid) * 2 + 22 ||
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        memcmp(p, ff_asf_header, sizeof(ff_asf_guid))) {
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        av_log(NULL, AV_LOG_ERROR,
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               "Corrupt stream (invalid ASF header, size=%d)\n",
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               mms->asf_header_size);
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        return AVERROR_INVALIDDATA;
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    }
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    end = mms->asf_header + mms->asf_header_size;
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    p += sizeof(ff_asf_guid) + 14;
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    while(end - p >= sizeof(ff_asf_guid) + 8) {
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        uint64_t chunksize;
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        if (!memcmp(p, ff_asf_data_header, sizeof(ff_asf_guid))) {
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            chunksize = 50; // see Reference [2] section 5.1
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        } else {
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            chunksize = AV_RL64(p + sizeof(ff_asf_guid));
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        }
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        if (!chunksize || chunksize > end - p) {
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            av_log(NULL, AV_LOG_ERROR,
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                   "Corrupt stream (header chunksize %"PRId64" is invalid)\n",
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                   chunksize);
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            return AVERROR_INVALIDDATA;
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        }
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        if (!memcmp(p, ff_asf_file_header, sizeof(ff_asf_guid))) {
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            /* read packet size */
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            if (end - p > sizeof(ff_asf_guid) * 2 + 68) {
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                mms->asf_packet_len = AV_RL32(p + sizeof(ff_asf_guid) * 2 + 64);
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                if (mms->asf_packet_len <= 0 || mms->asf_packet_len > sizeof(mms->in_buffer)) {
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                    av_log(NULL, AV_LOG_ERROR,
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                           "Corrupt stream (too large pkt_len %d)\n",
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                           mms->asf_packet_len);
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                    return AVERROR_INVALIDDATA;
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                }
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            }
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        } else if (!memcmp(p, ff_asf_stream_header, sizeof(ff_asf_guid))) {
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            flags     = AV_RL16(p + sizeof(ff_asf_guid)*3 + 24);
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            stream_id = flags & 0x7F;
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            //The second condition is for checking CS_PKT_STREAM_ID_REQUEST packet size,
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            //we can calcuate the packet size by stream_num.
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            //Please see function send_stream_selection_request().
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            if (mms->stream_num < MAX_STREAMS &&
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                    46 + mms->stream_num * 6 < sizeof(mms->out_buffer)) {
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                mms->streams[mms->stream_num].id = stream_id;
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                mms->stream_num++;
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            } else {
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                av_log(NULL, AV_LOG_ERROR,
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                       "Corrupt stream (too many A/V streams)\n");
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                return AVERROR_INVALIDDATA;
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            }
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        } else if (!memcmp(p, ff_asf_head1_guid, sizeof(ff_asf_guid))) {
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            chunksize = 46; // see references [2] section 3.4. This should be set 46.
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        }
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        p += chunksize;
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    }
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    return 0;
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}