[FFmpeg-devel] [patch]MMS protocol over TCP

[Michael Niedermayer]

On Thu, Apr 08, 2010 at 09:08:34PM +0800, zhentan feng wrote:
> Hi
> 
> On Thu, Apr 8, 2010 at 3:04 AM, Michael Niedermayer <michaelni at gmx.at>wrote:
> 
> > On Thu, Apr 08, 2010 at 01:52:26AM +0800, zhentan feng wrote:
> > [...]
> > [...]
> > > ===================================================================
> > > --- mmst.c    (revision 5735)
> > > +++ mmst.c    (working copy)
> > > @@ -321,6 +321,8 @@
> > >                              mms->asf_header =
> > av_realloc(mms->asf_header,
> > >                                                mms->asf_header_size
> > >                                                + mms->pkt_buf_len);
> > > +                            if (!mms->asf_header)
> > > +                                return -1;
> >
> > thats probably a memleak and should return ENOMEM
> >
> >
> fixed.
> 
> > [...]
> > > @@ -563,10 +563,14 @@
> > >      int err = AVERROR(EIO);
> > >      int ret;
> > >
> > > +    h->is_streamed = 1;
> > > +    h->priv_data = av_mallocz(sizeof(MMSContext));
> > > +    mms = (MMSContext *) h->priv_data;
> >
> > that cast should be unneeded
> >
> > fixed.
> 
> I attached the new version patch below.
> zhentan
> -- 
> Best wishes~

[...]
> +
> +/** Add prefixes to MMST command packet. */
> +static void insert_command_prefixes(MMSContext *mms,
> +        uint32_t prefix1, uint32_t prefix2)
> +{
> +    ByteIOContext *context= &mms->outgoing_packet_data;
> +
> +    put_le32(context, prefix1); // first prefix
> +    put_le32(context, prefix2); // second prefix
> +}
> +
> +/** Send a prepared MMST command packet. */
> +static int send_command_packet(MMSContext *mms)
> +{
> +    ByteIOContext *context= &mms->outgoing_packet_data;
> +    int exact_length= url_ftell(context);
> +    int first_length= exact_length - 16;
> +    int len8= first_length/8;
> +    int write_result;
> +
> +    // update packet length fields.
> +    url_fseek(context, 8, SEEK_SET);
> +    put_le32(context, first_length);
> +    url_fseek(context, 16, SEEK_SET);
> +    put_le32(context, len8);
> +    url_fseek(context, 32, SEEK_SET);
> +    put_le32(context, len8-2);

why dont you just write into the buffer with a uint8_t pointer
using intreadwrite.h / bytestream.h ?



[...]

> +static void handle_packet_stream_changing_type(MMSContext *mms)
> +{
> +    ByteIOContext pkt;
> +    dprintf(NULL, "Stream changing!\n");
> +
> +    // 40 is the packet header size, without the prefixea.s
> +    init_put_byte(&pkt, mms->incoming_buffer+40,
> +            mms->incoming_buffer_length-40, 0, NULL, NULL, NULL, NULL);
> +    get_le32(&pkt);                                 // prefix 1
> +    mms->header_packet_id= (get_le32(&pkt) & 0xff); // prefix 2
> +    dprintf(NULL, "Changed header prefix to 0x%x", mms->header_packet_id);
> +}

thats an interresting way to read 1 byte of an array


[...]
> +/** Read incoming MMST media, header or command packet. */
> +static MMSSCPacketType get_tcp_server_response(MMSContext *mms)
> +{
> +    int read_result;
> +    MMSSCPacketType packet_type= -1;
> +    int done;
> +
> +    do {
> +        done= 1;
> +        if((read_result= url_read_complete(mms->mms_hd, mms->incoming_buffer, 8))==8) {
> +            // handle command packet.
> +            if(AV_RL32(mms->incoming_buffer + 4)==0xb00bface) {
> +                mms->incoming_flags= mms->incoming_buffer[3];
> +                read_result= url_read_complete(mms->mms_hd, mms->incoming_buffer+8, 4);
> +                if(read_result == 4) {

> +                    int length_remaining= AV_RL32(mms->incoming_buffer+8) + 4;
> +
> +                    dprintf(NULL, "Length remaining is %d\n", length_remaining);
> +                    // read the rest of the packet.
> +                    if (length_remaining > sizeof(mms->incoming_buffer) - 12) {
> +                        dprintf("Incoming message len %d exceeds buffer len %d\n",
> +                            length_remaining, sizeof(mms->incoming_buffer) - 12);
> +                        break;
> +                    }

doesnt catch negative values


> +                    read_result = url_read_complete(mms->mms_hd, mms->incoming_buffer + 12,
> +                                                  length_remaining) ;
> +                    if (read_result == length_remaining) {
> +                        mms->incoming_buffer_length= length_remaining+12;
> +                        packet_type= AV_RL16(mms->incoming_buffer+36);
> +
> +                    } else {
> +                        dprintf(NULL, "3 read returned %d!\n", read_result);
> +                    }
> +                } else {
> +                    dprintf(NULL, "2 read returned %d!\n", read_result);
> +                }
> +            } else {
> +                int length_remaining;
> +                int packet_id_type;
> +                int tmp;
> +
> +                assert(mms->pkt_buf_len==0);
> +
> +                //** VERIFY LENGTH REMAINING HAS SPACE
> +                // note we cache the first 8 bytes,
> +                // then fill up the buffer with the others
> +                tmp                       = AV_RL16(mms->incoming_buffer + 6);
> +                length_remaining          = (tmp - 8) & 0xffff;
> +                mms->incoming_packet_seq  = AV_RL32(mms->incoming_buffer);
> +                packet_id_type            = mms->incoming_buffer[4];
> +                mms->incoming_flags       = mms->incoming_buffer[5];
> +                mms->pkt_buf_len          = length_remaining;
> +                mms->pkt_read_ptr         = mms->incoming_buffer;
> +
> +                if (length_remaining > sizeof(mms->incoming_buffer)) {
> +                    dprintf("Incoming data len %d exceeds buffer len %d\n",
> +                            length_remaining, sizeof(mms->incoming_buffer));
> +                    break;
> +                }

the length_remaining variables is used before checking it

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

He who knows, does not speak. He who speaks, does not know. -- Lao Tsu
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: Digital signature
URL: <http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/attachments/20100408/bc06a898/attachment.pgp>