Merging in file transfer support. Most important points from my review

are fixed now, time to let it settle in and get people to try it.

1 files changed, 1153 insertions, 0 deletions

diff --git a/protocols/jabber/s5bytestream.c b/protocols/jabber/s5bytestream.c
new file mode 100644
index 00000000..58a6c2e4
--- /dev/null
+++ b/protocols/jabber/s5bytestream.c
@@ -0,0 +1,1153 @@
+/***************************************************************************\
+*                                                                           *
+*  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 "lib/ftutil.h"
+#include <poll.h>
+
+struct bs_transfer {
+
+	struct jabber_transfer *tf;
+
+	jabber_streamhost_t *sh;
+	GSList *streamhosts;
+
+	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;
+	
+	char peek_buf[64];
+	int peek_buf_len;
+};
+
+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)); 
+
+char *socks5_reply_code[] = {
+	"succeeded",
+	"general SOCKS server failure",
+	"connection not allowed by ruleset",
+	"Network unreachable",
+	"Host unreachable",
+	"Connection refused",
+	"TTL expired",
+	"Command not supported",
+	"Address type not supported",
+	"unassigned"};
+
+/* 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, GSList *streamhosts );
+gboolean jabber_bs_send_handshake( gpointer data, gint fd, b_input_condition cond );
+static xt_status jabber_bs_send_handle_activate( struct im_connection *ic, struct xt_node *node, struct xt_node *orig );
+void jabber_bs_send_activate( struct bs_transfer *bt );
+
+/*
+ * 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;
+	jabber_streamhost_t *sh;
+
+	if ( bt->connect_timeout )
+	{
+		b_event_remove( bt->connect_timeout );
+		bt->connect_timeout = 0;
+	}
+
+	if ( tf->watch_in )
+		b_event_remove( tf->watch_in );
+	
+	if( tf->watch_out )
+		b_event_remove( tf->watch_out );
+	
+	g_free( bt->pseudoadr );
+
+	while( bt->streamhosts )
+	{
+		sh = bt->streamhosts->data;
+		bt->streamhosts = g_slist_remove( bt->streamhosts, sh );
+		g_free( sh->jid );
+		g_free( sh->host );
+		g_free( sh );
+	}
+	
+	g_free( bt );
+
+	jabber_si_free_transfer( ft );
+}
+
+/*
+ * Checks if buflen data is available on the socket and
+ * writes it to buffer if that's the case.
+ */
+gboolean jabber_bs_peek( struct bs_transfer *bt, void *buffer, int buflen )
+{
+	int ret;
+	int fd = bt->tf->fd;
+
+	if( buflen > sizeof( bt->peek_buf ) )
+		return jabber_bs_abort( bt, "BUG: %d > sizeof(peek_buf)", buflen );
+
+	ASSERTSOCKOP( ret = recv( fd, bt->peek_buf + bt->peek_buf_len,
+		buflen - bt->peek_buf_len, 0 ), "recv() on SOCKS5 connection" );
+
+	if( ret == 0 )
+		return jabber_bs_abort( bt, "Remote end closed connection" );
+	
+	bt->peek_buf_len += ret;
+	memcpy( buffer, bt->peek_buf, bt->peek_buf_len );
+	
+	if( bt->peek_buf_len == buflen )
+	{
+		/* If we have everything the caller wanted, reset the peek buffer. */
+		bt->peek_buf_len = 0;
+		return buflen;
+	}
+	else
+		return bt->peek_buf_len;
+}
+
+
+/* 
+ * 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;
+}
+
+/* 
+ * Polls the socket, checks for errors and removes a connect timer
+ * if there is one.
+ */
+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;
+}
+
+/*
+ * Used for receive and send path.
+ */
+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_send_handshake_abort( bt, error );
+	else
+		return jabber_bs_recv_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;
+	GSList *shlist=NULL;
+	struct xt_node *shnode;
+
+	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;
+	}
+
+	shnode = qnode->children;
+	while( ( shnode = xt_find_node( shnode, "streamhost" ) ) )
+	{
+		char *jid, *host, *port_s;
+		int port;
+		if( ( jid = xt_find_attr( shnode, "jid" ) ) &&
+		    ( host = xt_find_attr( shnode, "host" ) ) &&
+		    ( port_s = xt_find_attr( shnode, "port" ) ) &&
+		    ( sscanf( port_s, "%d", &port ) == 1 ) )
+		{
+			jabber_streamhost_t *sh = g_new0( jabber_streamhost_t, 1 );
+			sh->jid = g_strdup(jid);
+			sh->host = g_strdup(host);
+			sprintf( sh->port, "%u", port );
+			shlist = g_slist_append( shlist, sh );
+		}
+		shnode = shnode->next;
+	}
+	
+	if( !shlist )
+	{
+		imcb_log( ic, "WARNING: Received incomplete SI bytestream request, no parseable streamhost entries");
+		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->streamhosts = shlist;
+	bt->sh = shlist->data;
+	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, -1, 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;
+	int gret;
+
+	if ( ( fd != -1 ) && !jabber_bs_poll( bt, fd, &revents ) )
+		return FALSE;
+	
+	switch( bt->phase ) 
+	{
+	case BS_PHASE_CONNECT:
+		{
+			struct addrinfo hints, *rp;
+
+			memset( &hints, 0, sizeof( struct addrinfo ) );
+			hints.ai_socktype = SOCK_STREAM;
+
+			if ( ( gret = getaddrinfo( bt->sh->host, bt->sh->port, &hints, &rp ) ) != 0 )
+				return jabber_bs_abort( bt, "getaddrinfo() failed: %s", gai_strerror( gret ) );
+
+			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, bt->sh->host, bt->sh->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;
+		}
+	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 < 5 ) /* header up to address length */
+				return TRUE;
+			else if( ret < sizeof( struct socks5_message ) )
+			{
+				/* Either a buggy proxy or just one that doesnt regard the SHOULD in XEP-0065
+				 * saying the reply SHOULD contain the address */
+
+				ASSERTSOCKOP( ret = recv( fd, &socks5_reply, ret, 0 ), "Dequeuing after MSG_PEEK" );
+			}
+
+			if( !( socks5_reply.ver == 5 ) ||
+			    !( socks5_reply.cmdrep.rep == 0 ) ) {
+			    	char errstr[128] = "";
+				if( ( socks5_reply.ver == 5 ) && ( socks5_reply.cmdrep.rep < 
+				    ( sizeof( socks5_reply_code ) / sizeof( socks5_reply_code[0] ) ) ) ) {
+					sprintf( errstr, "with \"%s\" ", socks5_reply_code[ socks5_reply.cmdrep.rep ] );
+				}
+				return jabber_bs_abort( bt, "SOCKS5 CONNECT failed %s(reply: ver=%d, rep=%d, atyp=%d, addrlen=%d)", 
+					errstr,
+					socks5_reply.ver,
+					socks5_reply.cmdrep.rep,
+					socks5_reply.atyp,
+					socks5_reply.addrlen);
+			}
+			
+			/* usually a proxy sends back the 40 bytes address but I encountered at least one (of jabber.cz) 
+			 * that sends atyp=0 addrlen=0 and only 6 bytes (one less than one would expect).
+			 * Therefore I removed the wait for more bytes. Since we don't care about what else the proxy
+			 * is sending, it shouldnt matter */
+
+			if( bt->tf->ft->sending )
+				jabber_bs_send_activate( bt );
+			else
+				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;
+	GSList *shlist;
+
+	imcb_log( tf->ic, "Transferring file %s: connection to streamhost %s:%s failed (%s)", 
+		  tf->ft->file_name, 
+		  bt->sh->host,
+		  bt->sh->port,
+		  error );
+
+	/* Alright, this streamhost failed, let's try the next... */
+	bt->phase = BS_PHASE_CONNECT;
+	shlist = g_slist_find( bt->streamhosts, bt->sh );
+	if( shlist && shlist->next )
+	{
+		bt->sh = shlist->next->data;
+		return jabber_bs_recv_handshake( bt, -1, 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;
+	/* MUST always return FALSE! */
+	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, 
+		  bt->sh->host,
+		  bt->sh->port );
+
+	tf->ft->data = tf;
+	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", bt->sh->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 != -1 ) /* 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;
+
+	if( tf->bytesread >= tf->ft->file_size )
+		imcb_file_finished( tf->ft );
+
+	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, -1 , 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 " );
+	
+	/* TODO: catch broken pipe */
+	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 );
+
+	if( tf->byteswritten >= ft->file_size )
+		imcb_file_finished( ft );
+	else
+		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( strcmp( jid, tf->ini_jid ) == 0 )
+	{
+		/* we're streamhost and target */
+		if( bt->phase == BS_PHASE_REPLY )
+		{
+			/* handshake went through, let's start transferring */
+			tf->ft->write_request( tf->ft );
+		}
+	} else
+	{
+		/* using a proxy, abort listen */
+
+		if( tf->watch_in )
+		{
+			b_event_remove( tf->watch_in );
+			tf->watch_in = 0;
+		}
+		
+		if( tf->fd != -1 ) {
+			closesocket( tf->fd );
+			tf->fd = -1;
+		}
+
+		if ( bt->connect_timeout )
+		{
+			b_event_remove( bt->connect_timeout );
+			bt->connect_timeout = 0;
+		}
+
+		GSList *shlist;
+		for( shlist = jd->streamhosts ; shlist ; shlist = g_slist_next( shlist ) )
+		{
+			jabber_streamhost_t *sh = shlist->data;
+			if( strcmp( sh->jid, jid ) == 0 )
+			{
+				bt->sh = sh;
+				jabber_bs_recv_handshake( bt, -1, 0 );
+				return XT_HANDLED;
+			}
+		}
+
+		imcb_log( ic, "WARNING: Received SOCKS5 bytestream reply with unknown streamhost %s", jid );
+	}
+
+	return XT_HANDLED;
+}
+
+/* 
+ * Tell the proxy to activate the stream. Looks like this:
+ *
+ * <iq type=set>
+ * 	<query xmlns=bs sid=sid>
+ * 		<activate>tgt_jid</activate>
+ * 	</query>
+ * </iq>
+ */
+void jabber_bs_send_activate( struct bs_transfer *bt )
+{
+	struct xt_node *node;
+
+	node = xt_new_node( "activate", bt->tf->tgt_jid, NULL );
+	node = xt_new_node( "query", NULL, node );
+	xt_add_attr( node, "xmlns", XMLNS_BYTESTREAMS );
+	xt_add_attr( node, "sid", bt->tf->sid );
+	node = jabber_make_packet( "iq", "set", bt->sh->jid, node );
+
+	jabber_cache_add( bt->tf->ic, node, jabber_bs_send_handle_activate );
+
+	jabber_write_packet( bt->tf->ic, node );
+}
+
+/*
+ * The proxy has activated the bytestream.
+ * We can finally start pushing some data out.
+ */
+static xt_status jabber_bs_send_handle_activate( struct im_connection *ic, struct xt_node *node, struct xt_node *orig )
+{
+	char *sid;
+	GSList *tflist;
+	struct jabber_transfer *tf = NULL;
+	struct xt_node *query;
+	struct jabber_data *jd = ic->proto_data;
+
+	query = xt_find_node( orig->children, "query" );
+	sid = xt_find_attr( query, "sid" );
+
+	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 activation for unknown stream" );
+		return XT_HANDLED;
+	}
+
+	imcb_log( tf->ic, "File %s: SOCKS5 handshake and activation successful! Transfer about to start...", tf->ft->file_name );
+
+	/* handshake went through, let's start transferring */
+	tf->ft->write_request( tf->ft );
+
+	return XT_HANDLED;
+}
+
+jabber_streamhost_t *jabber_si_parse_proxy( struct im_connection *ic, char *proxy )
+{
+	char *host, *port, *jid;
+	jabber_streamhost_t *sh;
+
+	if( ( ( host = strchr( proxy, ',' ) ) == 0 ) ||
+	     ( ( port = strchr( host+1, ',' ) ) == 0 ) ) {
+		imcb_log( ic, "Error parsing proxy setting: \"%s\" (ignored)", proxy );
+		return NULL;
+	}
+	
+	jid = proxy;
+	*host++ = '\0';
+	*port++ = '\0';
+
+	sh = g_new0( jabber_streamhost_t, 1 );
+	sh->jid = g_strdup( jid );
+	sh->host = g_strdup( host );
+	strcpy( sh->port, port );
+
+	return sh;
+}
+
+void jabber_si_set_proxies( struct bs_transfer *bt )
+{
+	struct jabber_transfer *tf = bt->tf;
+	struct jabber_data *jd = tf->ic->proto_data;
+	char *proxysetting = g_strdup ( set_getstr( &tf->ic->acc->set, "proxy" ) );
+	char *proxy, *next, *errmsg = NULL;
+	char port[6];
+	char host[HOST_NAME_MAX+1];
+	jabber_streamhost_t *sh, *sh2;
+	GSList *streamhosts = jd->streamhosts;
+
+	proxy = proxysetting;
+	while ( proxy && ( *proxy!='\0' ) ) {
+		if( ( next = strchr( proxy, ';' ) ) )
+			*next++ = '\0';	
+		
+		if( strcmp( proxy, "<local>" ) == 0 ) {
+			if( ( tf->fd = ft_listen( &tf->saddr, host, port, FALSE, &errmsg ) ) != -1 ) {
+				sh = g_new0( jabber_streamhost_t, 1 );
+				sh->jid = g_strdup( tf->ini_jid );
+				sh->host = g_strdup( host );
+				strcpy( sh->port, port );
+				bt->streamhosts = g_slist_append( bt->streamhosts, sh );
+
+				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 );
+			} else {
+				imcb_log( tf->ic, "Transferring file %s: couldn't listen locally(non fatal, check your ft_listen setting in bitlbee.conf): %s",
+					  tf->ft->file_name,
+					  errmsg );
+			}
+		} else if( strcmp( proxy, "<auto>" ) == 0 ) {
+			while ( streamhosts ) {
+				sh = g_new0( jabber_streamhost_t, 1 );
+				sh2 = streamhosts->data;
+				sh->jid = g_strdup( sh2->jid );
+				sh->host = g_strdup( sh2->host );
+				strcpy( sh->port, sh2->port );
+				bt->streamhosts = g_slist_append( bt->streamhosts, sh );
+				streamhosts = g_slist_next( streamhosts );
+			}
+		} else if( ( sh = jabber_si_parse_proxy( tf->ic, proxy ) ) )
+			bt->streamhosts = g_slist_append( bt->streamhosts, sh );
+		proxy = next;
+	}
+}
+
+/*
+ * Starts a bytestream.
+ */
+gboolean jabber_bs_send_start( struct jabber_transfer *tf )
+{
+	struct bs_transfer *bt;
+	sha1_state_t sha;
+	char hash_hex[41];
+	unsigned char hash[20];
+	int i,ret;
+
+	/* 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;
+
+	jabber_si_set_proxies( bt );
+
+	ret = jabber_bs_send_request( tf, bt->streamhosts);
+
+	return ret;
+}
+
+gboolean jabber_bs_send_request( struct jabber_transfer *tf, GSList *streamhosts )
+{
+	struct xt_node *shnode, *query, *iq;
+
+	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" );
+
+	while( streamhosts ) {
+		jabber_streamhost_t *sh = streamhosts->data;
+		shnode = xt_new_node( "streamhost", NULL, NULL );
+		xt_add_attr( shnode, "jid", sh->jid );
+		xt_add_attr( shnode, "host", sh->host );
+		xt_add_attr( shnode, "port", sh->port );
+
+		xt_add_child( query, shnode );
+
+		streamhosts = g_slist_next( streamhosts );
+	}
+
+
+	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;
+	struct jabber_data *jd = tf->ic->proto_data;
+
+	/* TODO: did the receiver get here somehow??? */
+	imcb_log( tf->ic, "Transferring file %s: SOCKS5 handshake failed: %s", 
+		  tf->ft->file_name, 
+		  error );
+
+	if( jd->streamhosts==NULL ) /* we're done here unless we have a proxy to try */
+		imcb_file_canceled( tf->ft, error );
+
+	/* MUST always return FALSE! */
+	return FALSE;
+}
+
+/*
+ * 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 );
+			int ret;
+
+			if( !( ret = jabber_bs_peek( bt, &socks5_connect, msgsize ) ) )
+				return FALSE;
+
+			if( ret < msgsize )
+				return TRUE;
+
+			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->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