PeerStreamer

/*

 * MMS protocol common definitions.

 * Copyright (c) 2006,2007 Ryan Martell

 * Copyright (c) 2007 Bj?rn Axelsson

 * Copyright (c) 2010 Zhentan Feng <spyfeng at gmail dot com>

 *

 * This file is part of Libav.

 *

 * Libav 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.

 *

 * Libav 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 Libav; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include "mms.h"

#include "asf.h"

#include "libavutil/intreadwrite.h"

#if FF_API_MAX_STREAMS

#define MMS_MAX_STREAMS MAX_STREAMS

#else

#define MMS_MAX_STREAMS 256    /**< arbitrary sanity check value */

#endif

int ff_mms_read_header(MMSContext *mms, uint8_t *buf, const int size)

{

    char *pos;

    int size_to_copy;

    int remaining_size = mms->asf_header_size - mms->asf_header_read_size;

    size_to_copy = FFMIN(size, remaining_size);

    pos = mms->asf_header + mms->asf_header_read_size;

    memcpy(buf, pos, size_to_copy);

    if (mms->asf_header_read_size == mms->asf_header_size) {

        av_freep(&mms->asf_header); // which contains asf header

    }

    mms->asf_header_read_size += size_to_copy;

    return size_to_copy;

}

int ff_mms_read_data(MMSContext *mms, uint8_t *buf, const int size)

{

    int read_size;

    read_size = FFMIN(size, mms->remaining_in_len);

    memcpy(buf, mms->read_in_ptr, read_size);

    mms->remaining_in_len -= read_size;

    mms->read_in_ptr      += read_size;

    return read_size;

}

int ff_mms_asf_header_parser(MMSContext *mms)

{

    uint8_t *p = mms->asf_header;

    uint8_t *end;

    int flags, stream_id;

    mms->stream_num = 0;

    if (mms->asf_header_size < sizeof(ff_asf_guid) * 2 + 22 ||

        memcmp(p, ff_asf_header, sizeof(ff_asf_guid))) {

        av_log(NULL, AV_LOG_ERROR,

               "Corrupt stream (invalid ASF header, size=%d)\n",

               mms->asf_header_size);

        return AVERROR_INVALIDDATA;

    }

    end = mms->asf_header + mms->asf_header_size;

    p += sizeof(ff_asf_guid) + 14;

    while(end - p >= sizeof(ff_asf_guid) + 8) {

        uint64_t chunksize;

        if (!memcmp(p, ff_asf_data_header, sizeof(ff_asf_guid))) {

            chunksize = 50; // see Reference [2] section 5.1

        } else {

            chunksize = AV_RL64(p + sizeof(ff_asf_guid));

        }

        if (!chunksize || chunksize > end - p) {

            av_log(NULL, AV_LOG_ERROR,

                   "Corrupt stream (header chunksize %"PRId64" is invalid)\n",

                   chunksize);

            return AVERROR_INVALIDDATA;

        }

        if (!memcmp(p, ff_asf_file_header, sizeof(ff_asf_guid))) {

            /* read packet size */

            if (end - p > sizeof(ff_asf_guid) * 2 + 68) {

                mms->asf_packet_len = AV_RL32(p + sizeof(ff_asf_guid) * 2 + 64);

                if (mms->asf_packet_len <= 0 || mms->asf_packet_len > sizeof(mms->in_buffer)) {

                    av_log(NULL, AV_LOG_ERROR,

                           "Corrupt stream (too large pkt_len %d)\n",

                           mms->asf_packet_len);

                    return AVERROR_INVALIDDATA;

                }

            }

        } else if (!memcmp(p, ff_asf_stream_header, sizeof(ff_asf_guid))) {

            flags     = AV_RL16(p + sizeof(ff_asf_guid)*3 + 24);

            stream_id = flags & 0x7F;

            //The second condition is for checking CS_PKT_STREAM_ID_REQUEST packet size,

            //we can calcuate the packet size by stream_num.

            //Please see function send_stream_selection_request().

            if (mms->stream_num < MMS_MAX_STREAMS &&

                    46 + mms->stream_num * 6 < sizeof(mms->out_buffer)) {

                mms->streams = av_fast_realloc(mms->streams,

                                   &mms->nb_streams_allocated,

                                   (mms->stream_num + 1) * sizeof(MMSStream));

                mms->streams[mms->stream_num].id = stream_id;

                mms->stream_num++;

            } else {

                av_log(NULL, AV_LOG_ERROR,

                       "Corrupt stream (too many A/V streams)\n");

                return AVERROR_INVALIDDATA;

            }

        } else if (!memcmp(p, ff_asf_ext_stream_header, sizeof(ff_asf_guid))) {

            if (end - p >= 88) {

                int stream_count = AV_RL16(p + 84), ext_len_count = AV_RL16(p + 86);

                uint64_t skip_bytes = 88;

                while (stream_count--) {

                    if (end - p < skip_bytes + 4) {

                        av_log(NULL, AV_LOG_ERROR,

                               "Corrupt stream (next stream name length is not in the buffer)\n");

                        return AVERROR_INVALIDDATA;

                    }

                    skip_bytes += 4 + AV_RL16(p + skip_bytes + 2);

                }

                while (ext_len_count--) {

                    if (end - p < skip_bytes + 22) {

                        av_log(NULL, AV_LOG_ERROR,

                               "Corrupt stream (next extension system info length is not in the buffer)\n");

                        return AVERROR_INVALIDDATA;

                    }

                    skip_bytes += 22 + AV_RL32(p + skip_bytes + 18);

                }

                if (end - p < skip_bytes) {

                    av_log(NULL, AV_LOG_ERROR,

                           "Corrupt stream (the last extension system info length is invalid)\n");

                    return AVERROR_INVALIDDATA;

                }

                if (chunksize - skip_bytes > 24)

                    chunksize = skip_bytes;

            }

        } else if (!memcmp(p, ff_asf_head1_guid, sizeof(ff_asf_guid))) {

            chunksize = 46; // see references [2] section 3.4. This should be set 46.

        }

        p += chunksize;

    }

    return 0;

}