PeerStreamer

/*

 * MMS protocol over HTTP

 * 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

 */

/*

 * Reference

 * Windows Media HTTP Streaming Protocol.

 * http://msdn.microsoft.com/en-us/library/cc251059(PROT.10).aspx

 */

#include <string.h>

#include "libavutil/intreadwrite.h"

#include "libavutil/avstring.h"

#include "libavformat/internal.h"

#include "mms.h"

#include "asf.h"

#include "http.h"

#include "url.h"

#define CHUNK_HEADER_LENGTH 4   // 2bytes chunk type and 2bytes chunk length.

#define EXT_HEADER_LENGTH   8   // 4bytes sequence, 2bytes useless and 2bytes chunk length.

// see Ref 2.2.1.8

#define USERAGENT  "User-Agent: NSPlayer/4.1.0.3856\r\n"

// see Ref 2.2.1.4.33

// the guid value can be changed to any valid value.

#define CLIENTGUID "Pragma: xClientGUID={c77e7400-738a-11d2-9add-0020af0a3278}\r\n"

// see Ref 2.2.3 for packet type define:

// chunk type contains 2 fields: Frame and PacketID.

// Frame is 0x24 or 0xA4(rarely), different PacketID indicates different packet type.

typedef enum {

    CHUNK_TYPE_DATA          = 0x4424,

    CHUNK_TYPE_ASF_HEADER    = 0x4824,

    CHUNK_TYPE_END           = 0x4524,

    CHUNK_TYPE_STREAM_CHANGE = 0x4324,

} ChunkType;

typedef struct {

    MMSContext mms;

    int request_seq;  ///< request packet sequence

    int chunk_seq;    ///< data packet sequence

} MMSHContext;

static int mmsh_close(URLContext *h)

{

    MMSHContext *mmsh = (MMSHContext *)h->priv_data;

    MMSContext *mms   = &mmsh->mms;

    if (mms->mms_hd)

        ffurl_close(mms->mms_hd);

    av_free(mms->streams);

    av_free(mms->asf_header);

    av_freep(&h->priv_data);

    return 0;

}

static ChunkType get_chunk_header(MMSHContext *mmsh, int *len)

{

    MMSContext *mms = &mmsh->mms;

    uint8_t chunk_header[CHUNK_HEADER_LENGTH];

    uint8_t ext_header[EXT_HEADER_LENGTH];

    ChunkType chunk_type;

    int chunk_len, res, ext_header_len;

    res = ffurl_read_complete(mms->mms_hd, chunk_header, CHUNK_HEADER_LENGTH);

    if (res != CHUNK_HEADER_LENGTH) {

        av_log(NULL, AV_LOG_ERROR, "Read data packet header failed!\n");

        return AVERROR(EIO);

    }

    chunk_type = AV_RL16(chunk_header);

    chunk_len  = AV_RL16(chunk_header + 2);

    switch (chunk_type) {

    case CHUNK_TYPE_END:

    case CHUNK_TYPE_STREAM_CHANGE:

        ext_header_len = 4;

        break;

    case CHUNK_TYPE_ASF_HEADER:

    case CHUNK_TYPE_DATA:

        ext_header_len = 8;

        break;

    default:

        av_log(NULL, AV_LOG_ERROR, "Strange chunk type %d\n", chunk_type);

        return AVERROR_INVALIDDATA;

    }

    res = ffurl_read_complete(mms->mms_hd, ext_header, ext_header_len);

    if (res != ext_header_len) {

        av_log(NULL, AV_LOG_ERROR, "Read ext header failed!\n");

        return AVERROR(EIO);

    }

    *len = chunk_len - ext_header_len;

    if (chunk_type == CHUNK_TYPE_END || chunk_type == CHUNK_TYPE_DATA)

        mmsh->chunk_seq = AV_RL32(ext_header);

    return chunk_type;

}

static int read_data_packet(MMSHContext *mmsh, const int len)

{

    MMSContext *mms   = &mmsh->mms;

    int res;

    if (len > sizeof(mms->in_buffer)) {

        av_log(NULL, AV_LOG_ERROR,

               "Data packet length %d exceeds the in_buffer size %zu\n",

               len, sizeof(mms->in_buffer));

        return AVERROR(EIO);

    }

    res = ffurl_read_complete(mms->mms_hd, mms->in_buffer, len);

    av_dlog(NULL, "Data packet len = %d\n", len);

    if (res != len) {

        av_log(NULL, AV_LOG_ERROR, "Read data packet failed!\n");

        return AVERROR(EIO);

    }

    if (len > mms->asf_packet_len) {

        av_log(NULL, AV_LOG_ERROR,

               "Chunk length %d exceed packet length %d\n",len, mms->asf_packet_len);

        return AVERROR_INVALIDDATA;

    } else {

        memset(mms->in_buffer + len, 0, mms->asf_packet_len - len); // padding

    }

    mms->read_in_ptr      = mms->in_buffer;

    mms->remaining_in_len = mms->asf_packet_len;

    return 0;

}

static int get_http_header_data(MMSHContext *mmsh)

{

    MMSContext *mms = &mmsh->mms;

    int res, len;

    ChunkType chunk_type;

    for (;;) {

        len = 0;

        res = chunk_type = get_chunk_header(mmsh, &len);

        if (res < 0) {

            return res;

        } else if (chunk_type == CHUNK_TYPE_ASF_HEADER){

            // get asf header and stored it

            if (!mms->header_parsed) {

                if (mms->asf_header) {

                    if (len != mms->asf_header_size) {

                        mms->asf_header_size = len;

                        av_dlog(NULL, "Header len changed from %d to %d\n",

                                mms->asf_header_size, len);

                        av_freep(&mms->asf_header);

                    }

                }

                mms->asf_header = av_mallocz(len);

                if (!mms->asf_header) {

                    return AVERROR(ENOMEM);

                }

                mms->asf_header_size = len;

            }

            if (len > mms->asf_header_size) {

                av_log(NULL, AV_LOG_ERROR,

                       "Asf header packet len = %d exceed the asf header buf size %d\n",

                       len, mms->asf_header_size);

                return AVERROR(EIO);

            }

            res = ffurl_read_complete(mms->mms_hd, mms->asf_header, len);

            if (res != len) {

                av_log(NULL, AV_LOG_ERROR,

                       "Recv asf header data len %d != expected len %d\n", res, len);

                return AVERROR(EIO);

            }

            mms->asf_header_size = len;

            if (!mms->header_parsed) {

                res = ff_mms_asf_header_parser(mms);

                mms->header_parsed = 1;

                return res;

            }

        } else if (chunk_type == CHUNK_TYPE_DATA) {

            // read data packet and do padding

            return read_data_packet(mmsh, len);

        } else {

            if (len) {

                if (len > sizeof(mms->in_buffer)) {

                    av_log(NULL, AV_LOG_ERROR,

                           "Other packet len = %d exceed the in_buffer size %zu\n",

                           len, sizeof(mms->in_buffer));

                    return AVERROR(EIO);

                }

                res = ffurl_read_complete(mms->mms_hd, mms->in_buffer, len);

                if (res != len) {

                    av_log(NULL, AV_LOG_ERROR, "Read other chunk type data failed!\n");

                    return AVERROR(EIO);

                } else {

                    av_dlog(NULL, "Skip chunk type %d \n", chunk_type);

                    continue;

                }

            }

        }

    }

    return 0;

}

static int mmsh_open(URLContext *h, const char *uri, int flags)

{

    int i, port, err;

    char httpname[256], path[256], host[128], location[1024];

    char *stream_selection = NULL;

    char headers[1024];

    MMSHContext *mmsh;

    MMSContext *mms;

    mmsh = h->priv_data = av_mallocz(sizeof(MMSHContext));

    if (!h->priv_data)

        return AVERROR(ENOMEM);

    mmsh->request_seq = h->is_streamed = 1;

    mms = &mmsh->mms;

    av_strlcpy(location, uri, sizeof(location));

    av_url_split(NULL, 0, NULL, 0,

        host, sizeof(host), &port, path, sizeof(path), location);

    if (port<0)

        port = 80; // default mmsh protocol port

    ff_url_join(httpname, sizeof(httpname), "http", NULL, host, port, path);

    if (ffurl_alloc(&mms->mms_hd, httpname, URL_RDONLY) < 0) {

        return AVERROR(EIO);

    }

    snprintf(headers, sizeof(headers),

             "Accept: */*\r\n"

             USERAGENT

             "Host: %s:%d\r\n"

             "Pragma: no-cache,rate=1.000000,stream-time=0,"

             "stream-offset=0:0,request-context=%u,max-duration=0\r\n"

             CLIENTGUID

             "Connection: Close\r\n\r\n",

             host, port, mmsh->request_seq++);

    ff_http_set_headers(mms->mms_hd, headers);

    err = ffurl_connect(mms->mms_hd);

    if (err) {

        goto fail;

    }

    err = get_http_header_data(mmsh);

    if (err) {

        av_log(NULL, AV_LOG_ERROR, "Get http header data failed!\n");

        goto fail;

    }

    // close the socket and then reopen it for sending the second play request.

    ffurl_close(mms->mms_hd);

    memset(headers, 0, sizeof(headers));

    if (ffurl_alloc(&mms->mms_hd, httpname, URL_RDONLY) < 0) {

        return AVERROR(EIO);

    }

    stream_selection = av_mallocz(mms->stream_num * 19 + 1);

    if (!stream_selection)

        return AVERROR(ENOMEM);

    for (i = 0; i < mms->stream_num; i++) {

        char tmp[20];

        err = snprintf(tmp, sizeof(tmp), "ffff:%d:0 ", mms->streams[i].id);

        if (err < 0)

            goto fail;

        av_strlcat(stream_selection, tmp, mms->stream_num * 19 + 1);

    }

    // send play request

    err = snprintf(headers, sizeof(headers),

                   "Accept: */*\r\n"

                   USERAGENT

                   "Host: %s:%d\r\n"

                   "Pragma: no-cache,rate=1.000000,request-context=%u\r\n"

                   "Pragma: xPlayStrm=1\r\n"

                   CLIENTGUID

                   "Pragma: stream-switch-count=%d\r\n"

                   "Pragma: stream-switch-entry=%s\r\n"

                   "Connection: Close\r\n\r\n",

                   host, port, mmsh->request_seq++, mms->stream_num, stream_selection);

    av_freep(&stream_selection);

    if (err < 0) {

        av_log(NULL, AV_LOG_ERROR, "Build play request failed!\n");

        goto fail;

    }

    av_dlog(NULL, "out_buffer is %s", headers);

    ff_http_set_headers(mms->mms_hd, headers);

    err = ffurl_connect(mms->mms_hd);

    if (err) {

          goto fail;

    }

    err = get_http_header_data(mmsh);

    if (err) {

        av_log(NULL, AV_LOG_ERROR, "Get http header data failed!\n");

        goto fail;

    }

    av_dlog(NULL, "Connection successfully open\n");

    return 0;

fail:

    av_freep(&stream_selection);

    mmsh_close(h);

    av_dlog(NULL, "Connection failed with error %d\n", err);

    return err;

}

static int handle_chunk_type(MMSHContext *mmsh)

{

    MMSContext *mms = &mmsh->mms;

    int res, len = 0;

    ChunkType chunk_type;

    chunk_type = get_chunk_header(mmsh, &len);

    switch (chunk_type) {

    case CHUNK_TYPE_END:

        mmsh->chunk_seq = 0;

        av_log(NULL, AV_LOG_ERROR, "Stream ended!\n");

        return AVERROR(EIO);

    case CHUNK_TYPE_STREAM_CHANGE:

        mms->header_parsed = 0;

        if (res = get_http_header_data(mmsh)) {

            av_log(NULL, AV_LOG_ERROR,"Stream changed! Failed to get new header!\n");

            return res;

        }

        break;

    case CHUNK_TYPE_DATA:

        return read_data_packet(mmsh, len);

    default:

        av_log(NULL, AV_LOG_ERROR, "Recv other type packet %d\n", chunk_type);

        return AVERROR_INVALIDDATA;

    }

    return 0;

}

static int mmsh_read(URLContext *h, uint8_t *buf, int size)

{

    int res = 0;

    MMSHContext *mmsh = h->priv_data;

    MMSContext *mms   = &mmsh->mms;

    do {

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

            // copy asf header into buffer

            res = ff_mms_read_header(mms, buf, size);

        } else {

            if (!mms->remaining_in_len && (res = handle_chunk_type(mmsh)))

                return res;

            res = ff_mms_read_data(mms, buf, size);

        }

    } while (!res);

    return res;

}

URLProtocol ff_mmsh_protocol = {

    .name      = "mmsh",

    .url_open  = mmsh_open,

    .url_read  = mmsh_read,

    .url_write = NULL,

    .url_seek  = NULL,

    .url_close = mmsh_close,

};