From 8d00b1e039938c13d47c116827f74211a2d89838 Mon Sep 17 00:00:00 2001
From: erdgeist <>
Date: Sat, 15 Dec 2007 17:11:43 +0000
Subject: Prepare udp connection id generation and checking
---
ot_udp.c | 30 ++++++++++++++++++++++++++++--
1 file changed, 28 insertions(+), 2 deletions(-)
diff --git a/ot_udp.c b/ot_udp.c
index 56b5f44..f34d08f 100644
--- a/ot_udp.c
+++ b/ot_udp.c
@@ -4,6 +4,7 @@
/* System */
#include <string.h>
#include <arpa/inet.h>
+#include <stdio.h>
/* Libowfat */
#include "socket.h"
@@ -17,6 +18,24 @@
static char static_inbuf[8192];
static char static_outbuf[8192];
+static const uint8_t g_static_connid[8] = { 0x23, 0x42, 0x05, 0x17, 0xde, 0x41, 0x50, 0xff };
+
+static void udp_make_connectionid( uint32_t * connid, const char * remoteip ) {
+ /* Touch unused variable */
+ remoteip = remoteip;
+
+ /* Use a static secret for now */
+ memcpy( connid, g_static_connid, 8 );
+}
+
+static int udp_test_connectionid( const uint32_t * const connid, const char * remoteip ) {
+ /* Touch unused variable */
+ remoteip = remoteip;
+
+ /* Test against our static secret */
+ return !memcmp( connid, g_static_connid, 8 );
+}
+
/* UDP implementation according to http://xbtt.sourceforge.net/udp_tracker_protocol.html */
void handle_udp4( int64 serversocket ) {
ot_peer peer;
@@ -44,8 +63,9 @@ void handle_udp4( int64 serversocket ) {
switch( ntohl( inpacket[2] ) ) {
case 0: /* This is a connect action */
- outpacket[0] = 0; outpacket[1] = inpacket[3];
- outpacket[2] = inpacket[0]; outpacket[3] = inpacket[1];
+ outpacket[0] = 0;
+ outpacket[1] = inpacket[3];
+ udp_make_connectionid( outpacket + 2, remoteip );
socket_send4( serversocket, static_outbuf, 16, remoteip, remoteport );
stats_issue_event( EVENT_CONNECT, 0, 16 );
break;
@@ -54,6 +74,9 @@ void handle_udp4( int64 serversocket ) {
if( r < 98 )
return;
+ if( !udp_test_connectionid( inpacket, remoteip ))
+ fprintf( stderr, "UDP Connection id missmatch\n" );
+
numwant = 200;
/* We do only want to know, if it is zero */
left = inpacket[64/4] | inpacket[68/4];
@@ -93,6 +116,9 @@ void handle_udp4( int64 serversocket ) {
break;
case 2: /* This is a scrape action */
+ if( !udp_test_connectionid( inpacket, remoteip ))
+ fprintf( stderr, "UDP Connection id missmatch\n" );
+
outpacket[0] = htonl( 2 ); /* scrape action */
outpacket[1] = inpacket[12/4];
--
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