Jabber file transfer now also with sending! You can't use a proxy yet when

sending, that's my next task. You can use proxies when receiving though!

I also changed the buffering strategy. Previously receiving continued till some
buffer limit was reached, now only one message is received and receiving stops
till it is delivered. This keeps the buffering space per file transfer to a
minimum(currently 4k). Makes sense when used on a public server. For public
servers a throughput maximum would also be interesting...

1 files changed, 919 insertions, 0 deletions

diff --git a/protocols/jabber/s5bytestream.c b/protocols/jabber/s5bytestream.c
new file mode 100644
index 00000000..de173d19
--- /dev/null
+++ b/protocols/jabber/s5bytestream.c
@@ -0,0 +1,919 @@
+/***************************************************************************\
+*                                                                           *
+*  BitlBee - An IRC to IM gateway                                           *
+*  Jabber module - SOCKS5 Bytestreams ( XEP-0065 )                          *
+*                                                                           *
+*  Copyright 2007 Uli Meis <a.sporto+bee@gmail.com>                         *
+*                                                                           *
+*  This program is free software; you can redistribute it and/or modify     *
+*  it under the terms of the GNU General Public License as published by     *
+*  the Free Software Foundation; either version 2 of the License, or        *
+*  (at your option) any later version.                                      *
+*                                                                           *
+*  This program 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 General Public License for more details.                             *
+*                                                                           *
+*  You should have received a copy of the GNU General Public License along  *
+*  with this program; if not, write to the Free Software Foundation, Inc.,  *
+*  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.              *
+*                                                                           *
+\***************************************************************************/
+
+#include "jabber.h"
+#include "sha1.h"
+#include <poll.h>
+
+struct bs_transfer {
+
+	struct jabber_transfer *tf;
+
+	/* <query> element and <streamhost> elements */
+	struct xt_node *qnode, *shnode;
+
+	enum 
+	{ 
+		BS_PHASE_CONNECT, 
+		BS_PHASE_CONNECTED, 
+		BS_PHASE_REQUEST, 
+		BS_PHASE_REPLY
+	} phase;
+
+	/* SHA1( SID + Initiator JID + Target JID) */
+	char *pseudoadr;
+
+	gint connect_timeout;
+};
+
+struct socks5_message
+{
+	unsigned char ver;
+	union
+	{
+		unsigned char cmd;
+		unsigned char rep;
+	} cmdrep;
+	unsigned char rsv;
+	unsigned char atyp;
+	unsigned char addrlen;
+	unsigned char address[40];
+	in_port_t port;
+} __attribute__ ((packed)); 
+
+/* connect() timeout in seconds. */
+#define JABBER_BS_CONTIMEOUT 15
+/* listen timeout */
+#define JABBER_BS_LISTEN_TIMEOUT  90
+
+/* very useful */
+#define ASSERTSOCKOP(op, msg) \
+	if( (op) == -1 ) \
+		return jabber_bs_abort( bt , msg ": %s", strerror( errno ) );
+
+gboolean jabber_bs_abort( struct bs_transfer *bt, char *format, ... );
+void jabber_bs_canceled( file_transfer_t *ft , char *reason );
+void jabber_bs_free_transfer( file_transfer_t *ft);
+gboolean jabber_bs_connect_timeout( gpointer data, gint fd, b_input_condition cond );
+gboolean jabber_bs_poll( struct bs_transfer *bt, int fd, short *revents );
+gboolean jabber_bs_peek( struct bs_transfer *bt, void *buffer, int buflen );
+
+void jabber_bs_recv_answer_request( struct bs_transfer *bt );
+gboolean jabber_bs_recv_read( gpointer data, gint fd, b_input_condition cond );
+gboolean jabber_bs_recv_write_request( file_transfer_t *ft );
+gboolean jabber_bs_recv_handshake( gpointer data, gint fd, b_input_condition cond );
+gboolean jabber_bs_recv_handshake_abort( struct bs_transfer *bt, char *error );
+int jabber_bs_recv_request( struct im_connection *ic, struct xt_node *node, struct xt_node *qnode);
+
+gboolean jabber_bs_send_handshake_abort( struct bs_transfer *bt, char *error );
+gboolean jabber_bs_send_request( struct jabber_transfer *tf, char *host, char *port );
+gboolean jabber_bs_send_handshake( gpointer data, gint fd, b_input_condition cond );
+gboolean jabber_bs_send_listen( struct bs_transfer *bt, struct sockaddr_storage *saddr, char *host, char *port );
+
+/*
+ * Frees a bs_transfer struct and calls the SI free function
+ */
+void jabber_bs_free_transfer( file_transfer_t *ft) {
+	struct jabber_transfer *tf = ft->data;
+	struct bs_transfer *bt = tf->streamhandle;
+
+	if ( tf->watch_in )
+		b_event_remove( tf->watch_in );
+	
+	if( tf->watch_out )
+		b_event_remove( tf->watch_out );
+	
+	g_free( bt->pseudoadr );
+	xt_free_node( bt->qnode );
+	g_free( bt );
+
+	jabber_si_free_transfer( ft );
+}
+
+gboolean jabber_bs_peek( struct bs_transfer *bt, void *buffer, int buflen )
+{
+	int ret;
+	int fd = bt->tf->fd;
+
+	ASSERTSOCKOP( ret = recv( fd, buffer, buflen, MSG_PEEK ), "MSG_PEEK'ing" );
+
+	if( ret == 0 )
+		return jabber_bs_abort( bt, "Remote end closed connection" );
+		
+	if( ret < buflen )
+		return ret;
+
+	ASSERTSOCKOP( ret = recv( fd, buffer, buflen, 0 ), "Dequeuing after MSG_PEEK" );
+
+	if( ret != buflen )
+		return jabber_bs_abort( bt, "recv returned less than previous recv with MSG_PEEK" );
+	
+	return ret;
+}
+
+
+/* 
+ * This function is scheduled in bs_handshake via b_timeout_add after a (non-blocking) connect().
+ */
+gboolean jabber_bs_connect_timeout( gpointer data, gint fd, b_input_condition cond )
+{
+	struct bs_transfer *bt = data;
+
+	bt->connect_timeout = 0;
+
+	jabber_bs_abort( bt, "no connection after %d seconds", bt->tf->ft->sending ? JABBER_BS_LISTEN_TIMEOUT : JABBER_BS_CONTIMEOUT );
+
+	return FALSE;
+}
+
+gboolean jabber_bs_poll( struct bs_transfer *bt, int fd, short *revents )
+{
+	struct pollfd pfd = { .fd = fd, .events = POLLHUP|POLLERR };
+	
+	if ( bt->connect_timeout )
+	{
+		b_event_remove( bt->connect_timeout );
+		bt->connect_timeout = 0;
+	}
+
+	ASSERTSOCKOP( poll( &pfd, 1, 0 ), "poll()" )
+
+	if( pfd.revents & POLLERR )
+	{
+		int sockerror;
+		socklen_t errlen = sizeof( sockerror );
+
+		if ( getsockopt( fd, SOL_SOCKET, SO_ERROR, &sockerror, &errlen ) )
+			return jabber_bs_abort( bt, "getsockopt() failed, unknown socket error during SOCKS5 handshake (weird!)" );
+
+		if ( bt->phase == BS_PHASE_CONNECTED )
+			return jabber_bs_abort( bt, "connect failed: %s", strerror( sockerror ) );
+
+		return jabber_bs_abort( bt, "Socket error during SOCKS5 handshake(weird!): %s", strerror( sockerror ) );
+	}
+
+	if( pfd.revents & POLLHUP )
+		return jabber_bs_abort( bt, "Remote end closed connection" );
+	
+	*revents = pfd.revents;
+	
+	return TRUE;
+}
+
+gboolean jabber_bs_abort( struct bs_transfer *bt, char *format, ... )
+{
+	va_list params;
+	va_start( params, format );
+	char error[128];
+
+	if( vsnprintf( error, 128, format, params ) < 0 )
+		sprintf( error, "internal error parsing error string (BUG)" );
+	va_end( params );
+	if( bt->tf->ft->sending )
+		return jabber_bs_recv_handshake_abort( bt, error );
+	else
+		return jabber_bs_send_handshake_abort( bt, error );
+}
+
+/* Bad luck */
+void jabber_bs_canceled( file_transfer_t *ft , char *reason )
+{
+	struct jabber_transfer *tf = ft->data;
+
+	imcb_log( tf->ic, "File transfer aborted: %s", reason );
+}
+
+/*
+ * Parses an incoming bytestream request and calls jabber_bs_handshake on success.
+ */
+int jabber_bs_recv_request( struct im_connection *ic, struct xt_node *node, struct xt_node *qnode)
+{
+	char *sid, *ini_jid, *tgt_jid, *mode, *iq_id;
+	struct jabber_data *jd = ic->proto_data;
+	struct jabber_transfer *tf = NULL;
+	GSList *tflist;
+	struct bs_transfer *bt;
+
+	sha1_state_t sha;
+	char hash_hex[41];
+	unsigned char hash[20];
+	int i;
+	
+	if( !(iq_id   = xt_find_attr( node, "id" ) ) ||
+	    !(ini_jid = xt_find_attr( node, "from" ) ) ||
+	    !(tgt_jid = xt_find_attr( node, "to" ) ) ||
+	    !(sid     = xt_find_attr( qnode, "sid" ) ) )
+	{
+		imcb_log( ic, "WARNING: Received incomplete SI bytestream request");
+		return XT_HANDLED;
+	}
+
+	if( ( mode = xt_find_attr( qnode, "mode" ) ) &&
+	      ( strcmp( mode, "tcp" ) != 0 ) ) 
+	{
+		imcb_log( ic, "WARNING: Received SI Request for unsupported bytestream mode %s", xt_find_attr( qnode, "mode" ) );
+		return XT_HANDLED;
+	}
+
+	/* Let's see if we can find out what this bytestream should be for... */
+
+	for( tflist = jd->filetransfers ; tflist; tflist = g_slist_next(tflist) )
+	{
+		struct jabber_transfer *tft = tflist->data;
+		if( ( strcmp( tft->sid, sid ) == 0 ) &&
+		    ( strcmp( tft->ini_jid, ini_jid ) == 0 ) &&
+		    ( strcmp( tft->tgt_jid, tgt_jid ) == 0 ) )
+		{
+		    	tf = tft;
+			break;
+		}
+	}
+
+	if (!tf) 
+	{
+		imcb_log( ic, "WARNING: Received bytestream request from %s that doesn't match an SI request", ini_jid );
+		return XT_HANDLED;
+	}
+
+	/* iq_id and canceled can be reused since SI is done */
+	g_free( tf->iq_id );
+	tf->iq_id = g_strdup( iq_id );
+
+	tf->ft->canceled = jabber_bs_canceled;
+
+	/* SHA1( SID + Initiator JID + Target JID ) is given to the streamhost which it will match against the initiator's value */
+	sha1_init( &sha );
+	sha1_append( &sha, (unsigned char*) sid, strlen( sid ) );
+	sha1_append( &sha, (unsigned char*) ini_jid, strlen( ini_jid ) );
+	sha1_append( &sha, (unsigned char*) tgt_jid, strlen( tgt_jid ) );
+	sha1_finish( &sha, hash );
+	
+	for( i = 0; i < 20; i ++ )
+		sprintf( hash_hex + i * 2, "%02x", hash[i] );
+		
+	bt = g_new0( struct bs_transfer, 1 );
+	bt->tf = tf;
+	bt->qnode = xt_dup( qnode );
+	bt->shnode = bt->qnode->children;
+	bt->phase = BS_PHASE_CONNECT;
+	bt->pseudoadr = g_strdup( hash_hex );
+	tf->streamhandle = bt;
+	tf->ft->free = jabber_bs_free_transfer;
+
+	jabber_bs_recv_handshake( bt, 0, 0 ); 
+
+	return XT_HANDLED;
+}
+/*
+ * This is what a protocol handshake can look like in cooperative multitasking :)
+ * Might be confusing at first because it's called from different places and is recursing.
+ * (places being the event thread, bs_request, bs_handshake_abort, and itself)
+ *
+ * All in all, it turned out quite nice :)
+ */
+gboolean jabber_bs_recv_handshake( gpointer data, gint fd, b_input_condition cond )
+{
+
+	struct bs_transfer *bt = data;
+	short revents;
+
+	if ( !jabber_bs_poll( bt, fd, &revents ) )
+		return FALSE;
+	
+	switch( bt->phase ) 
+	{
+	case BS_PHASE_CONNECT:
+		{
+			struct xt_node *c;
+			char *host, *port;
+			struct addrinfo hints, *rp;
+
+			if( ( c = bt->shnode = xt_find_node( bt->shnode, "streamhost" ) ) &&
+			    ( port = xt_find_attr( c, "port" ) ) &&
+			    ( host = xt_find_attr( c, "host" ) ) &&
+			    xt_find_attr( c, "jid" ) )
+			{
+				memset( &hints, 0, sizeof( struct addrinfo ) );
+				hints.ai_socktype = SOCK_STREAM;
+
+				if ( getaddrinfo( host, port, &hints, &rp ) != 0 )
+					return jabber_bs_abort( bt, "getaddrinfo() failed: %s", strerror( errno ) );
+
+				ASSERTSOCKOP( bt->tf->fd = fd = socket( rp->ai_family, rp->ai_socktype, 0 ), "Opening socket" );
+
+				sock_make_nonblocking( fd );
+
+				imcb_log( bt->tf->ic, "File %s: Connecting to streamhost %s:%s", bt->tf->ft->file_name, host, port );
+
+				if( ( connect( fd, rp->ai_addr, rp->ai_addrlen ) == -1 ) &&
+				    ( errno != EINPROGRESS ) )
+					return jabber_bs_abort( bt , "connect() failed: %s", strerror( errno ) );
+
+				freeaddrinfo( rp );
+
+				bt->phase = BS_PHASE_CONNECTED;
+				
+				bt->tf->watch_out = b_input_add( fd, GAIM_INPUT_WRITE, jabber_bs_recv_handshake, bt );
+
+				/* since it takes forever(3mins?) till connect() fails on itself we schedule a timeout */
+				bt->connect_timeout = b_timeout_add( JABBER_BS_CONTIMEOUT * 1000, jabber_bs_connect_timeout, bt );
+
+				bt->tf->watch_in = 0;
+				return FALSE;
+			} else
+				return jabber_bs_abort( bt, c ? "incomplete streamhost entry: host=%s port=%s jid=%s" : NULL,
+								  host, port, xt_find_attr( c, "jid" ) );
+		}
+	case BS_PHASE_CONNECTED:
+		{
+			struct {
+				unsigned char ver;
+				unsigned char nmethods;
+				unsigned char method;
+			} socks5_hello = {
+				.ver = 5,
+				.nmethods = 1,
+				.method = 0x00 /* no auth */
+				/* one could also implement username/password. If you know
+				 * a jabber client or proxy that actually does it, tell me.
+				 */
+			};
+			
+			ASSERTSOCKOP( send( fd, &socks5_hello, sizeof( socks5_hello ) , 0 ), "Sending auth request" );
+
+			bt->phase = BS_PHASE_REQUEST;
+
+			bt->tf->watch_in = b_input_add( fd, GAIM_INPUT_READ, jabber_bs_recv_handshake, bt );
+
+			bt->tf->watch_out = 0;
+			return FALSE;
+		}
+	case BS_PHASE_REQUEST:
+		{
+			struct socks5_message socks5_connect = 
+			{
+				.ver = 5,
+				.cmdrep.cmd = 0x01,
+				.rsv = 0,
+				.atyp = 0x03,
+				.addrlen = strlen( bt->pseudoadr ),
+				.port = 0
+			};
+			int ret;
+			char buf[2];
+
+			/* If someone's trying to be funny and sends only one byte at a time we'll fail :) */
+			ASSERTSOCKOP( ret = recv( fd, buf, 2, 0 ) , "Receiving auth reply" );
+
+			if( !( ret == 2 ) ||
+			    !( buf[0] == 5 ) ||
+			    !( buf[1] == 0 ) )
+				return jabber_bs_abort( bt, "Auth not accepted by streamhost (reply: len=%d, ver=%d, status=%d)",
+									ret, buf[0], buf[1] );
+
+			/* copy hash into connect message */
+			memcpy( socks5_connect.address, bt->pseudoadr, socks5_connect.addrlen );
+
+			ASSERTSOCKOP( send( fd, &socks5_connect, sizeof( struct socks5_message ), 0 ) , "Sending SOCKS5 Connect" );
+
+			bt->phase = BS_PHASE_REPLY;
+
+			return TRUE;
+		}
+	case BS_PHASE_REPLY:
+		{
+			struct socks5_message socks5_reply;
+			int ret;
+
+			if ( !( ret = jabber_bs_peek( bt, &socks5_reply, sizeof( struct socks5_message ) ) ) )
+				return FALSE;
+
+			if ( ret < sizeof( socks5_reply ) )
+				return TRUE;
+
+			if( !( socks5_reply.ver == 5 ) ||
+			    !( socks5_reply.cmdrep.rep == 0 ) ||
+			    !( socks5_reply.atyp == 3 ) ||
+			    !( socks5_reply.addrlen == 40 ) )
+				return jabber_bs_abort( bt, "SOCKS5 CONNECT failed (reply: ver=%d, rep=%d, atyp=%d, addrlen=%d", 
+					socks5_reply.ver,
+					socks5_reply.cmdrep.rep,
+					socks5_reply.atyp,
+					socks5_reply.addrlen);
+
+			jabber_bs_recv_answer_request( bt );
+
+			return FALSE;
+		}
+	default:
+		/* BUG */
+		imcb_log( bt->tf->ic, "BUG in file transfer code: undefined handshake phase" );
+
+		bt->tf->watch_in = 0;
+		return FALSE;
+	}
+}
+
+/*
+ * If the handshake failed we can try the next streamhost, if there is one.
+ * An intelligent sender would probably specify himself as the first streamhost and
+ * a proxy as the second (Kopete and PSI are examples here). That way, a (potentially) 
+ * slow proxy is only used if neccessary. This of course also means, that the timeout
+ * per streamhost should be kept short. If one or two firewalled adresses are specified,
+ * they have to timeout first before a proxy is tried.
+ */
+gboolean jabber_bs_recv_handshake_abort( struct bs_transfer *bt, char *error )
+{
+	struct jabber_transfer *tf = bt->tf;
+	struct xt_node *reply, *iqnode;
+
+	if( bt->shnode ) 
+	{
+		imcb_log( tf->ic, "Transferring file %s: connection to streamhost %s:%s failed (%s)", 
+			  tf->ft->file_name, 
+			  xt_find_attr( bt->shnode, "host" ),
+			  xt_find_attr( bt->shnode, "port" ),
+			  error );
+
+		/* Alright, this streamhost failed, let's try the next... */
+		bt->phase = BS_PHASE_CONNECT;
+		bt->shnode = bt->shnode->next;
+		
+		/* the if is not neccessary but saves us one recursion */
+		if( bt->shnode )
+			return jabber_bs_recv_handshake( bt, 0, 0 );
+	}
+
+	/* out of stream hosts */
+
+	iqnode = jabber_make_packet( "iq", "result", tf->ini_jid, NULL );
+	reply = jabber_make_error_packet( iqnode, "item-not-found", "cancel" , "404" );
+	xt_free_node( iqnode );
+
+	xt_add_attr( reply, "id", tf->iq_id );
+		
+	if( !jabber_write_packet( tf->ic, reply ) )
+		imcb_log( tf->ic, "WARNING: Error transmitting bytestream response" );
+	xt_free_node( reply );
+
+	imcb_file_canceled( tf->ft, "couldn't connect to any streamhosts" );
+
+	bt->tf->watch_in = 0;
+	return FALSE;
+}
+
+/* 
+ * After the SOCKS5 handshake succeeds we need to inform the initiator which streamhost we chose.
+ * If he is the streamhost himself, he might already know that. However, if it's a proxy,
+ * the initiator will have to make a connection himself.
+ */
+void jabber_bs_recv_answer_request( struct bs_transfer *bt )
+{
+	struct jabber_transfer *tf = bt->tf;
+	struct xt_node *reply;
+
+	imcb_log( tf->ic, "File %s: established SOCKS5 connection to %s:%s", 
+		  tf->ft->file_name, 
+		  xt_find_attr( bt->shnode, "host" ),
+		  xt_find_attr( bt->shnode, "port" ) );
+
+	tf->ft->data = tf;
+	tf->ft->started = time( NULL );
+	tf->watch_in = b_input_add( tf->fd, GAIM_INPUT_READ, jabber_bs_recv_read, bt );
+	tf->ft->write_request = jabber_bs_recv_write_request;
+
+	reply = xt_new_node( "streamhost-used", NULL, NULL );
+	xt_add_attr( reply, "jid", xt_find_attr( bt->shnode, "jid" ) );
+
+	reply = xt_new_node( "query", NULL, reply );
+	xt_add_attr( reply, "xmlns", XMLNS_BYTESTREAMS );
+
+	reply = jabber_make_packet( "iq", "result", tf->ini_jid, reply );
+
+	xt_add_attr( reply, "id", tf->iq_id );
+		
+	if( !jabber_write_packet( tf->ic, reply ) )
+		imcb_file_canceled( tf->ft, "Error transmitting bytestream response" );
+	xt_free_node( reply );
+}
+
+/* 
+ * This function is called from write_request directly. If no data is available, it will install itself
+ * as a watcher for input on fd and once that happens, deliver the data and unschedule itself again.
+ */
+gboolean jabber_bs_recv_read( gpointer data, gint fd, b_input_condition cond )
+{
+	int ret;
+	struct bs_transfer *bt = data;
+	struct jabber_transfer *tf = bt->tf;
+
+	if( fd != 0 ) /* called via event thread */
+	{
+		tf->watch_in = 0;
+		ASSERTSOCKOP( ret = recv( fd, tf->ft->buffer, sizeof( tf->ft->buffer ), 0 ) , "Receiving" );
+	}
+	else
+	{
+		/* called directly. There might not be any data available. */
+		if( ( ( ret = recv( tf->fd, tf->ft->buffer, sizeof( tf->ft->buffer ), 0 ) ) == -1 ) &&
+		    ( errno != EAGAIN ) )
+		    return jabber_bs_abort( bt, "Receiving: %s", strerror( errno ) );
+
+		if( ( ret == -1 ) && ( errno == EAGAIN ) )
+		{
+			tf->watch_in = b_input_add( tf->fd, GAIM_INPUT_READ, jabber_bs_recv_read, bt );
+			return FALSE;
+		}
+	}
+
+	/* shouldn't happen since we know the file size */
+	if( ret == 0 )
+		return jabber_bs_abort( bt, "Remote end closed connection" );
+	
+	tf->bytesread += ret;
+
+	tf->ft->write( tf->ft, tf->ft->buffer, ret );	
+
+	return FALSE;
+}
+
+/* 
+ * imc callback that is invoked when it is ready to receive some data.
+ */
+gboolean jabber_bs_recv_write_request( file_transfer_t *ft )
+{
+	struct jabber_transfer *tf = ft->data;
+
+	if( tf->watch_in )
+	{
+		imcb_file_canceled( ft, "BUG in jabber file transfer: write_request called when already watching for input" );
+		return FALSE;
+	}
+	
+	jabber_bs_recv_read( tf->streamhandle, 0 , 0 );
+
+	return TRUE;
+}
+
+/* 
+ * Issues a write_request to imc.
+ * */
+gboolean jabber_bs_send_can_write( gpointer data, gint fd, b_input_condition cond )
+{
+	struct bs_transfer *bt = data;
+
+	bt->tf->watch_out = 0;
+
+	bt->tf->ft->write_request( bt->tf->ft );
+
+	return FALSE;
+}
+
+/*
+ * This should only be called if we can write, so just do it.
+ * Add a write watch so we can write more during the next cycle (if possible).
+ */
+gboolean jabber_bs_send_write( file_transfer_t *ft, char *buffer, unsigned int len )
+{
+	struct jabber_transfer *tf = ft->data;
+	struct bs_transfer *bt = tf->streamhandle;
+	int ret;
+
+	if( tf->watch_out )
+		return jabber_bs_abort( bt, "BUG: write() called while watching " );
+	
+	ASSERTSOCKOP( ret = send( tf->fd, buffer, len, 0 ), "Sending" );
+
+	tf->byteswritten += ret;
+	
+	/* TODO: this should really not be fatal */
+	if( ret < len )
+		return jabber_bs_abort( bt, "send() sent %d instead of %d (send buffer too big!)", ret, len );
+
+	bt->tf->watch_out = b_input_add( tf->fd, GAIM_INPUT_WRITE, jabber_bs_send_can_write, bt );
+		
+	return TRUE;
+}
+
+/*
+ * Handles the reply by the receiver containing the used streamhost.
+ */
+static xt_status jabber_bs_send_handle_reply(struct im_connection *ic, struct xt_node *node, struct xt_node *orig ) {
+	struct jabber_transfer *tf = NULL;
+	struct jabber_data *jd = ic->proto_data;
+	struct bs_transfer *bt;
+	GSList *tflist;
+	struct xt_node *c;
+	char *sid, *jid;
+
+	if( !( c = xt_find_node( node->children, "query" ) ) ||
+	    !( c = xt_find_node( c->children, "streamhost-used" ) ) ||
+	    !( jid = xt_find_attr( c, "jid" ) ) )
+
+	{
+		imcb_log( ic, "WARNING: Received incomplete bytestream reply" );
+		return XT_HANDLED;
+	}
+	
+	if( !( c = xt_find_node( orig->children, "query" ) ) ||
+	    !( sid = xt_find_attr( c, "sid" ) ) )
+	{
+		imcb_log( ic, "WARNING: Error parsing request corresponding to the incoming bytestream reply" );
+		return XT_HANDLED;
+	}
+
+	/* Let's see if we can find out what this bytestream should be for... */
+
+	for( tflist = jd->filetransfers ; tflist; tflist = g_slist_next(tflist) )
+	{
+		struct jabber_transfer *tft = tflist->data;
+		if( ( strcmp( tft->sid, sid ) == 0 ) )
+		{
+		    	tf = tft;
+			break;
+		}
+	}
+
+	if( !tf )
+	{
+		imcb_log( ic, "WARNING: Received SOCKS5 bytestream reply to unknown request" );
+		return XT_HANDLED;
+	}
+
+	bt = tf->streamhandle;
+
+	tf->accepted = TRUE;
+
+	if( bt->phase == BS_PHASE_REPLY )
+	{
+		/* handshake went through, let's start transferring */
+		tf->ft->started = time( NULL );
+		tf->ft->write_request( tf->ft );
+	}
+
+	return XT_HANDLED;
+}
+
+gboolean jabber_bs_send_start( struct jabber_transfer *tf )
+{
+	char host[INET6_ADDRSTRLEN], port[6];
+	struct bs_transfer *bt;
+	sha1_state_t sha;
+	char hash_hex[41];
+	unsigned char hash[20];
+	int i;
+
+	/* SHA1( SID + Initiator JID + Target JID ) is given to the streamhost which it will match against the initiator's value */
+	sha1_init( &sha );
+	sha1_append( &sha, (unsigned char*) tf->sid, strlen( tf->sid ) );
+	sha1_append( &sha, (unsigned char*) tf->ini_jid, strlen( tf->ini_jid ) );
+	sha1_append( &sha, (unsigned char*) tf->tgt_jid, strlen( tf->tgt_jid ) );
+	sha1_finish( &sha, hash );
+	
+	for( i = 0; i < 20; i ++ )
+		sprintf( hash_hex + i * 2, "%02x", hash[i] );
+		
+	bt = g_new0( struct bs_transfer, 1 );
+	bt->tf = tf;
+	bt->phase = BS_PHASE_CONNECT;
+	bt->pseudoadr = g_strdup( hash_hex );
+	tf->streamhandle = bt;
+	tf->ft->free = jabber_bs_free_transfer;
+	tf->ft->canceled = jabber_bs_canceled;
+
+	if ( !jabber_bs_send_listen( bt, &tf->saddr, host, port ) )
+		return FALSE;
+
+	bt->tf->watch_in = b_input_add( tf->fd, GAIM_INPUT_READ, jabber_bs_send_handshake, bt );
+	bt->connect_timeout = b_timeout_add( JABBER_BS_LISTEN_TIMEOUT * 1000, jabber_bs_connect_timeout, bt );
+	return jabber_bs_send_request( tf, host, port );
+}
+
+gboolean jabber_bs_send_request( struct jabber_transfer *tf, char *host, char *port )
+{
+	struct xt_node *sh, *query, *iq;
+
+	sh = xt_new_node( "streamhost", NULL, NULL );
+	xt_add_attr( sh, "jid", tf->ini_jid );
+	xt_add_attr( sh, "host", host );
+	xt_add_attr( sh, "port", port );
+
+	query = xt_new_node( "query", NULL, NULL );
+	xt_add_attr( query, "xmlns", XMLNS_BYTESTREAMS );
+	xt_add_attr( query, "sid", tf->sid );
+	xt_add_attr( query, "mode", "tcp" );
+	xt_add_child( query, sh );
+
+	iq = jabber_make_packet( "iq", "set", tf->tgt_jid, query );
+	xt_add_attr( iq, "from", tf->ini_jid );
+
+	jabber_cache_add( tf->ic, iq, jabber_bs_send_handle_reply );
+
+	if( !jabber_write_packet( tf->ic, iq ) )
+		imcb_file_canceled( tf->ft, "Error transmitting bytestream request" );
+	return TRUE;
+}
+
+gboolean jabber_bs_send_handshake_abort(struct bs_transfer *bt, char *error )
+{
+	struct jabber_transfer *tf = bt->tf;
+
+	imcb_log( tf->ic, "Transferring file %s: SOCKS5 handshake failed: %s", 
+		  tf->ft->file_name, 
+		  error );
+
+	imcb_file_canceled( tf->ft, error );
+
+	return FALSE;
+}
+
+/*
+ * Creates a listening socket and returns it in saddr_ptr.
+ */
+gboolean jabber_bs_send_listen( struct bs_transfer *bt, struct sockaddr_storage *saddr, char *host, char *port )
+{
+	struct jabber_transfer *tf = bt->tf;
+	int fd;
+	char hostname[ HOST_NAME_MAX + 1 ];
+	struct addrinfo hints, *rp;
+	socklen_t ssize = sizeof( struct sockaddr_storage );
+
+	/* won't be long till someone asks for this to be configurable :) */
+
+	ASSERTSOCKOP( gethostname( hostname, sizeof( hostname ) ), "gethostname()" );
+
+	memset( &hints, 0, sizeof( struct addrinfo ) );
+	hints.ai_socktype = SOCK_STREAM;
+	hints.ai_flags = AI_NUMERICSERV;
+
+	if ( getaddrinfo( hostname, "0", &hints, &rp ) != 0 )
+		return jabber_bs_abort( bt, "getaddrinfo()" );
+
+	memcpy( saddr, rp->ai_addr, rp->ai_addrlen );
+
+	ASSERTSOCKOP( fd = tf->fd = socket( saddr->ss_family, SOCK_STREAM, 0 ), "Opening socket" );
+
+	ASSERTSOCKOP( bind( fd, ( struct sockaddr *)saddr, rp->ai_addrlen ), "Binding socket" );
+	
+	freeaddrinfo( rp );
+
+	ASSERTSOCKOP( listen( fd, 1 ), "Making socket listen" );
+
+	if ( !inet_ntop( saddr->ss_family, saddr->ss_family == AF_INET ?
+			( void * )&( ( struct sockaddr_in * ) saddr )->sin_addr.s_addr : ( void * )&( ( struct sockaddr_in6 * ) saddr )->sin6_addr.s6_addr
+			, host, INET6_ADDRSTRLEN ) )
+		return jabber_bs_abort( bt, "inet_ntop failed on listening socket" );
+
+	ASSERTSOCKOP( getsockname( fd, ( struct sockaddr *)saddr, &ssize ), "Getting socket name" );
+
+	if( saddr->ss_family == AF_INET )
+		sprintf( port, "%d", ntohs( ( ( struct sockaddr_in *) saddr )->sin_port ) );
+	else
+		sprintf( port, "%d", ntohs( ( ( struct sockaddr_in6 *) saddr )->sin6_port ) );
+
+	return TRUE;
+}
+
+/*
+ * SOCKS5BYTESTREAM protocol for the sender
+ */
+gboolean jabber_bs_send_handshake( gpointer data, gint fd, b_input_condition cond )
+{
+	struct bs_transfer *bt = data;
+	struct jabber_transfer *tf = bt->tf;
+	short revents;
+
+	if ( !jabber_bs_poll( bt, fd, &revents ) )
+		return FALSE;
+	
+	switch( bt->phase ) 
+	{
+	case BS_PHASE_CONNECT:
+		{
+			struct sockaddr_storage clt_addr;
+			socklen_t ssize = sizeof( clt_addr );
+			
+			/* Connect */
+
+			ASSERTSOCKOP( tf->fd = accept( fd, (struct sockaddr *) &clt_addr, &ssize ), "Accepting connection" );
+
+			closesocket( fd );
+			fd = tf->fd;
+			sock_make_nonblocking( fd );
+			
+			bt->phase = BS_PHASE_CONNECTED;
+
+			bt->tf->watch_in = b_input_add( fd, GAIM_INPUT_READ, jabber_bs_send_handshake, bt );
+			return FALSE;
+		}
+	case BS_PHASE_CONNECTED:
+		{
+			int ret, have_noauth=FALSE;
+			struct {
+				unsigned char ver;
+				unsigned char method;
+			} socks5_auth_reply = { .ver = 5, .method = 0 };
+			struct {
+				unsigned char ver;
+				unsigned char nmethods;
+				unsigned char method;
+			} socks5_hello;
+
+			if( !( ret = jabber_bs_peek( bt, &socks5_hello, sizeof( socks5_hello ) ) ) )
+				return FALSE;
+
+			if( ret < sizeof( socks5_hello ) )
+				return TRUE;
+
+			if( !( socks5_hello.ver == 5 ) ||
+			    !( socks5_hello.nmethods >= 1 ) ||
+			    !( socks5_hello.nmethods < 32 ) )
+				return jabber_bs_abort( bt, "Invalid auth request ver=%d nmethods=%d method=%d", socks5_hello.ver, socks5_hello.nmethods, socks5_hello.method );
+
+			have_noauth = socks5_hello.method == 0;
+
+			if( socks5_hello.nmethods > 1 )
+			{
+				char mbuf[32];
+				int i;
+				ASSERTSOCKOP( ret = recv( fd, mbuf, socks5_hello.nmethods - 1, 0 ) , "Receiving auth methods" );
+				if( ret < ( socks5_hello.nmethods - 1 ) )
+					return jabber_bs_abort( bt, "Partial auth request");
+				for( i = 0 ; !have_noauth && ( i < socks5_hello.nmethods - 1 ) ; i ++ )
+					if( mbuf[i] == 0 )
+						have_noauth = TRUE;
+			}
+			
+			if( !have_noauth )
+				return jabber_bs_abort( bt, "Auth request didn't include no authentication" );
+
+			ASSERTSOCKOP( send( fd, &socks5_auth_reply, sizeof( socks5_auth_reply ) , 0 ), "Sending auth reply" );
+
+			bt->phase = BS_PHASE_REQUEST;
+
+			return TRUE;
+		}
+	case BS_PHASE_REQUEST:
+		{
+			struct socks5_message socks5_connect;
+			int msgsize = sizeof( struct socks5_message );
+
+			if( !jabber_bs_peek( bt, &socks5_connect, msgsize ) )
+				return FALSE;
+
+			if( !( socks5_connect.ver == 5) ||
+			    !( socks5_connect.cmdrep.cmd == 1 ) ||
+			    !( socks5_connect.atyp == 3 ) ||
+			    !(socks5_connect.addrlen == 40 ) )
+				return jabber_bs_abort( bt, "Invalid SOCKS5 Connect message (addrlen=%d, ver=%d, cmd=%d, atyp=%d)", socks5_connect.addrlen, socks5_connect.ver, socks5_connect.cmdrep.cmd, socks5_connect.atyp );
+			if( !( memcmp( socks5_connect.address, bt->pseudoadr, 40 ) == 0 ) )
+				return jabber_bs_abort( bt, "SOCKS5 Connect message contained wrong digest");
+
+			socks5_connect.cmdrep.rep = 0;
+
+			ASSERTSOCKOP( send( fd, &socks5_connect, msgsize, 0 ), "Sending connect reply" );
+
+			bt->phase = BS_PHASE_REPLY;
+
+			imcb_log( tf->ic, "File %s: SOCKS5 handshake successful! Transfer about to start...", tf->ft->file_name );
+
+			if( tf->accepted )
+			{
+				/* streamhost-used message came already in(possible?), let's start sending */
+				tf->ft->started = time( NULL );
+				tf->ft->write_request( tf->ft );
+			}
+
+			tf->watch_in = 0;
+			return FALSE;
+
+		}
+	default:
+		/* BUG */
+		imcb_log( bt->tf->ic, "BUG in file transfer code: undefined handshake phase" );
+
+		bt->tf->watch_in = 0;
+		return FALSE;
+	}
+}
+#undef ASSERTSOCKOP