(trunk libT) patch from wereHamster to simplify BT message parsing

diff --git a/libtransmission/peer-msgs.c b/libtransmission/peer-msgs.c
index ae1ba6953eeb30d71436be27441892c7e8a4fe4c..425645943bcc8fcd23686e97126bf5e222b9038e 100644 (file)
--- a/libtransmission/peer-msgs.c
+++ b/libtransmission/peer-msgs.c
@@ -106,14 +106,6 @@ enum
 ***  REQUEST MANAGEMENT
 **/
 
-enum
-{
-    AWAITING_BT_LENGTH,
-    AWAITING_BT_ID,
-    AWAITING_BT_MESSAGE,
-    AWAITING_BT_PIECE
-};
-
 struct peer_request
 {
     uint32_t    index;
@@ -252,10 +244,8 @@ reqListRemove( struct request_list *       list,
  * the current message that it's sending us. */
 struct tr_incoming
 {
-    uint8_t                id;
-    uint32_t               length; /* includes the +1 for id length */
-    struct peer_request    blockReq; /* metadata for incoming blocks */
-    struct evbuffer *      block; /* piece data for incoming blocks */
+    uint32_t          length; /* includes the +1 for id length */
+    struct evbuffer * block; /* piece data for incoming blocks */
 };
 
 /**
@@ -280,7 +270,6 @@ struct tr_peermsgs
     tr_bool         peerSentLtepHandshake;
     tr_bool         haveFastSet;
 
-    uint8_t         state;
     uint8_t         ut_pex_id;
     uint16_t        pexCount;
     uint16_t        pexCount6;
@@ -1279,48 +1268,14 @@ readBtLength( tr_peermsgs *     msgs,
         return READ_LATER;
 
     tr_peerIoReadUint32( msgs->peer->io, inbuf, &len );
+    msgs->incoming.length = len;
 
     if( len == 0 ) /* peer sent us a keepalive message */
         dbgmsg( msgs, "got KeepAlive" );
-    else
-    {
-        msgs->incoming.length = len;
-        msgs->state = AWAITING_BT_ID;
-    }
 
     return READ_NOW;
 }
 
-static int readBtMessage( tr_peermsgs *     msgs,
-                          struct evbuffer * inbuf,
-                          size_t            inlen );
-
-static int
-readBtId( tr_peermsgs *     msgs,
-          struct evbuffer * inbuf,
-          size_t            inlen )
-{
-    uint8_t id;
-
-    if( inlen < sizeof( uint8_t ) )
-        return READ_LATER;
-
-    tr_peerIoReadUint8( msgs->peer->io, inbuf, &id );
-    msgs->incoming.id = id;
-
-    if( id == BT_PIECE )
-    {
-        msgs->state = AWAITING_BT_PIECE;
-        return READ_NOW;
-    }
-    else if( msgs->incoming.length != 1 )
-    {
-        msgs->state = AWAITING_BT_MESSAGE;
-        return READ_NOW;
-    }
-    else return readBtMessage( msgs, inbuf, inlen - 1 );
-}
-
 static void
 updatePeerProgress( tr_peermsgs * msgs )
 {
@@ -1407,55 +1362,34 @@ readBtPiece( tr_peermsgs      * msgs,
              size_t             inlen,
              size_t           * setme_piece_bytes_read )
 {
-    struct peer_request * req = &msgs->incoming.blockReq;
+    struct peer_request req;
 
     assert( EVBUFFER_LENGTH( inbuf ) >= inlen );
     dbgmsg( msgs, "In readBtPiece" );
 
-    if( !req->length )
-    {
-        if( inlen < 8 )
-            return READ_LATER;
-
-        tr_peerIoReadUint32( msgs->peer->io, inbuf, &req->index );
-        tr_peerIoReadUint32( msgs->peer->io, inbuf, &req->offset );
-        req->length = msgs->incoming.length - 9;
-        dbgmsg( msgs, "got incoming block header %u:%u->%u", req->index, req->offset, req->length );
-        return READ_NOW;
-    }
-    else
-    {
-        int err;
+    tr_peerIoReadUint32( msgs->peer->io, inbuf, &req.index );
+    tr_peerIoReadUint32( msgs->peer->io, inbuf, &req.offset );
+    req.length = msgs->incoming.length - 9;
+    dbgmsg( msgs, "got incoming block header %u:%u->%u", req.index, req.offset, req.length );
 
-        /* read in another chunk of data */
-        const size_t nLeft = req->length - EVBUFFER_LENGTH( msgs->incoming.block );
-        size_t n = MIN( nLeft, inlen );
-        size_t i = n;
+    { 
+        int err;
 
-        while( i > 0 )
-        {
-            uint8_t buf[MAX_STACK_ARRAY_SIZE];
-            const size_t thisPass = MIN( i, sizeof( buf ) );
-            tr_peerIoReadBytes( msgs->peer->io, inbuf, buf, thisPass );
-            evbuffer_add( msgs->incoming.block, buf, thisPass );
-            i -= thisPass;
-        }
+        /* decrypt the whole block in one go */
+        evbuffer_expand( msgs->incoming.block, req.length );
+        tr_peerIoReadBytes( msgs->peer->io, inbuf, EVBUFFER_DATA( msgs->incoming.block ), req.length );
+        EVBUFFER_LENGTH( msgs->incoming.block ) += req.length;
 
-        fireClientGotData( msgs, n, TRUE );
-        *setme_piece_bytes_read += n;
-        dbgmsg( msgs, "got %zu bytes for block %u:%u->%u ... %d remain",
-               n, req->index, req->offset, req->length,
-               (int)( req->length - EVBUFFER_LENGTH( msgs->incoming.block ) ) );
-        if( EVBUFFER_LENGTH( msgs->incoming.block ) < req->length )
-            return READ_LATER;
+        fireClientGotData( msgs, req.length, TRUE );
+        *setme_piece_bytes_read += req.length;
+        dbgmsg( msgs, "got block %u:%u->%u", req.index, req.offset, req.length );
+        assert( EVBUFFER_LENGTH( msgs->incoming.block ) == req.length );
 
         /* we've got the whole block ... process it */
-        err = clientGotBlock( msgs, EVBUFFER_DATA( msgs->incoming.block ), req );
+        err = clientGotBlock( msgs, EVBUFFER_DATA( msgs->incoming.block ), &req );
 
         /* cleanup */
         evbuffer_drain( msgs->incoming.block, EVBUFFER_LENGTH( msgs->incoming.block ) );
-        req->length = 0;
-        msgs->state = AWAITING_BT_LENGTH;
         if( !err )
             return READ_NOW;
         else {
@@ -1466,28 +1400,31 @@ readBtPiece( tr_peermsgs      * msgs,
 }
 
 static int
-readBtMessage( tr_peermsgs * msgs, struct evbuffer * inbuf, size_t inlen )
+readBtMessage( tr_peermsgs * msgs, struct evbuffer * inbuf, size_t inlen, size_t * piece )
 {
+    int           ret = READ_NOW;
+    uint8_t       id;
     uint32_t      ui32;
     uint32_t      msglen = msgs->incoming.length;
-    const uint8_t id = msgs->incoming.id;
     const size_t  startBufLen = EVBUFFER_LENGTH( inbuf );
     const tr_bool fext = tr_peerIoSupportsFEXT( msgs->peer->io );
 
-    --msglen; /* id length */
-
     if( inlen < msglen )
         return READ_LATER;
 
+    tr_peerIoReadUint8( msgs->peer->io, inbuf, &id );
+
     dbgmsg( msgs, "got BT id %d, len %d, buffer size is %zu", (int)id, (int)msglen, inlen );
 
-    if( !messageLengthIsCorrect( msgs, id, msglen + 1 ) )
+    if( !messageLengthIsCorrect( msgs, id, msglen ) )
     {
         dbgmsg( msgs, "bad packet - BT message #%d with a length of %d", (int)id, (int)msglen );
         fireError( msgs, EMSGSIZE );
         return READ_ERR;
     }
 
+    --msglen;
+
     switch( id )
     {
         case BT_CHOKE:
@@ -1559,7 +1496,7 @@ readBtMessage( tr_peermsgs * msgs, struct evbuffer * inbuf, size_t inlen )
         }
 
         case BT_PIECE:
-            assert( 0 ); /* handled elsewhere! */
+            ret = readBtPiece( msgs, inbuf, msglen, piece );
             break;
 
         case BT_PORT:
@@ -1638,11 +1575,10 @@ readBtMessage( tr_peermsgs * msgs, struct evbuffer * inbuf, size_t inlen )
             break;
     }
 
-    assert( msglen + 1 == msgs->incoming.length );
-    assert( EVBUFFER_LENGTH( inbuf ) == startBufLen - msglen );
+    assert( EVBUFFER_LENGTH( inbuf ) == startBufLen - msglen - 1 );
 
-    msgs->state = AWAITING_BT_LENGTH;
-    return READ_NOW;
+    msgs->incoming.length = 0;
+    return ret;
 }
 
 static void
@@ -1743,27 +1679,15 @@ canRead( tr_peerIo * io, void * vmsgs, size_t * piece )
     const size_t      inlen = EVBUFFER_LENGTH( in );
 
     if( !inlen )
-    {
-        ret = READ_LATER;
-    }
-    else if( msgs->state == AWAITING_BT_PIECE )
-    {
-        ret = inlen ? readBtPiece( msgs, in, inlen, piece ) : READ_LATER;
-    }
-    else switch( msgs->state )
-    {
-        case AWAITING_BT_LENGTH:
-            ret = readBtLength ( msgs, in, inlen ); break;
-
-        case AWAITING_BT_ID:
-            ret = readBtId     ( msgs, in, inlen ); break;
-
-        case AWAITING_BT_MESSAGE:
-            ret = readBtMessage( msgs, in, inlen ); break;
+        return READ_LATER;
 
-        default:
-            assert( 0 );
-    }
+    /* Incoming data is processed in two stages. First the length is read
+     * and then readBtMessage() waits until all the data has arrived in
+     * the input buffer before starting to parse it */
+    if( msgs->incoming.length == 0 )
+        ret = readBtLength ( msgs, in, inlen );
+    else
+        ret = readBtMessage( msgs, in, inlen, piece );
 
     /* log the raw data that was read */
     if( ( ret != READ_ERR ) && ( EVBUFFER_LENGTH( in ) != inlen ) )
@@ -2246,7 +2170,6 @@ tr_peerMsgsNew( struct tr_torrent * torrent,
     m->peer->clientIsInterested = 0;
     m->peer->peerIsInterested = 0;
     m->peer->have = tr_bitfieldNew( torrent->info.pieceCount );
-    m->state = AWAITING_BT_LENGTH;
     m->pexTimer = tr_timerNew( m->session, pexPulse, m, PEX_INTERVAL );
     m->outMessages = evbuffer_new( );
     m->outMessagesBatchedAt = 0;