static int
parseHandshake (tr_handshake * handshake,
struct evbuffer * inbuf)
{
uint8_t name[HANDSHAKE_NAME_LEN];
uint8_t reserved[HANDSHAKE_FLAGS_LEN];
uint8_t hash[SHA_DIGEST_LENGTH];
tr_torrent * tor;
uint8_t peer_id[PEER_ID_LEN];
dbgmsg (handshake, "payload: need %d, got %zu",
HANDSHAKE_SIZE, evbuffer_get_length (inbuf));
if (evbuffer_get_length (inbuf) < HANDSHAKE_SIZE)
return READ_LATER;
/* confirm the protocol */
tr_peerIoReadBytes (handshake->io, inbuf, name, HANDSHAKE_NAME_LEN);
if (memcmp (name, HANDSHAKE_NAME, HANDSHAKE_NAME_LEN))
return HANDSHAKE_ENCRYPTION_WRONG;
/* read the reserved bytes */
tr_peerIoReadBytes (handshake->io, inbuf, reserved, HANDSHAKE_FLAGS_LEN);
/* torrent hash */
tr_peerIoReadBytes (handshake->io, inbuf, hash, sizeof (hash));
assert (tr_peerIoHasTorrentHash (handshake->io));
if (!tr_torrentExists (handshake->session, hash)
|| memcmp (hash, tr_peerIoGetTorrentHash (handshake->io), SHA_DIGEST_LENGTH))
{
dbgmsg (handshake, "peer returned the wrong hash. wtf?");
return HANDSHAKE_BAD_TORRENT;
}
/* peer_id */
tr_peerIoReadBytes (handshake->io, inbuf, peer_id, sizeof (peer_id));
tr_peerIoSetPeersId (handshake->io, peer_id);
/* peer id */
handshake->havePeerID = true;
dbgmsg (handshake, "peer-id is [%*.*s]", PEER_ID_LEN, PEER_ID_LEN, peer_id);
tor = tr_torrentFindFromHash (handshake->session, hash);
if (!memcmp (peer_id, tr_torrentGetPeerId(tor), PEER_ID_LEN))
{
dbgmsg (handshake, "streuth! we've connected to ourselves.");
return HANDSHAKE_PEER_IS_SELF;
}
/**
*** Extensions
**/
tr_peerIoEnableDHT (handshake->io, HANDSHAKE_HAS_DHT (reserved));
tr_peerIoEnableLTEP (handshake->io, HANDSHAKE_HAS_LTEP (reserved));
tr_peerIoEnableFEXT (handshake->io, HANDSHAKE_HAS_FASTEXT (reserved));
return HANDSHAKE_OK;
}
static int
readHandshake( tr_handshake * handshake,
struct evbuffer * inbuf )
{
uint8_t pstrlen;
uint8_t * pstr;
uint8_t reserved[HANDSHAKE_FLAGS_LEN];
uint8_t hash[SHA_DIGEST_LENGTH];
dbgmsg( handshake, "payload: need %d, got %zu",
INCOMING_HANDSHAKE_LEN, evbuffer_get_length( inbuf ) );
if( evbuffer_get_length( inbuf ) < INCOMING_HANDSHAKE_LEN )
return READ_LATER;
handshake->haveReadAnythingFromPeer = TRUE;
pstrlen = evbuffer_pullup( inbuf, 1 )[0]; /* peek, don't read. We may be
handing inbuf to AWAITING_YA */
if( pstrlen == 19 ) /* unencrypted */
{
tr_peerIoSetEncryption( handshake->io, PEER_ENCRYPTION_NONE );
if( handshake->encryptionMode == TR_ENCRYPTION_REQUIRED )
{
dbgmsg( handshake,
"peer is unencrypted, and we're disallowing that" );
return tr_handshakeDone( handshake, FALSE );
}
}
else /* encrypted or corrupt */
{
tr_peerIoSetEncryption( handshake->io, PEER_ENCRYPTION_RC4 );
if( tr_peerIoIsIncoming( handshake->io ) )
{
dbgmsg( handshake,
"I think peer is sending us an encrypted handshake..." );
setState( handshake, AWAITING_YA );
return READ_NOW;
}
tr_cryptoDecrypt( handshake->crypto, 1, &pstrlen, &pstrlen );
if( pstrlen != 19 )
{
dbgmsg( handshake,
"I think peer has sent us a corrupt handshake..." );
return tr_handshakeDone( handshake, FALSE );
}
}
evbuffer_drain( inbuf, 1 );
/* pstr (BitTorrent) */
pstr = tr_new( uint8_t, pstrlen + 1 );
tr_peerIoReadBytes( handshake->io, inbuf, pstr, pstrlen );
pstr[pstrlen] = '\0';
if( strcmp( (char*)pstr, "BitTorrent protocol" ) )
{
tr_free( pstr );
return tr_handshakeDone( handshake, FALSE );
}
tr_free( pstr );
/* reserved bytes */
tr_peerIoReadBytes( handshake->io, inbuf, reserved, sizeof( reserved ) );
/**
*** Extensions
**/
tr_peerIoEnableLTEP( handshake->io, HANDSHAKE_HAS_LTEP( reserved ) );
tr_peerIoEnableFEXT( handshake->io, HANDSHAKE_HAS_FASTEXT( reserved ) );
tr_peerIoEnableDHT( handshake->io, HANDSHAKE_HAS_DHT( reserved ) );
/* torrent hash */
tr_peerIoReadBytes( handshake->io, inbuf, hash, sizeof( hash ) );
if( tr_peerIoIsIncoming( handshake->io ) )
{
if( !tr_torrentExists( handshake->session, hash ) )
{
dbgmsg( handshake, "peer is trying to connect to us for a torrent we don't have." );
return tr_handshakeDone( handshake, FALSE );
}
else
{
assert( !tr_peerIoHasTorrentHash( handshake->io ) );
tr_peerIoSetTorrentHash( handshake->io, hash );
}
}
else /* outgoing */
{
assert( tr_peerIoHasTorrentHash( handshake->io ) );
if( memcmp( hash, tr_peerIoGetTorrentHash( handshake->io ),
SHA_DIGEST_LENGTH ) )
{
dbgmsg( handshake, "peer returned the wrong hash. wtf?" );
return tr_handshakeDone( handshake, FALSE );
}
}
/**
*** If it's an incoming message, we need to send a response handshake
**/
if( !handshake->haveSentBitTorrentHandshake )
{
uint8_t msg[HANDSHAKE_SIZE];
buildHandshakeMessage( handshake, msg );
tr_peerIoWriteBytes( handshake->io, msg, sizeof( msg ), FALSE );
handshake->haveSentBitTorrentHandshake = 1;
}
setReadState( handshake, AWAITING_PEER_ID );
return READ_NOW;
}