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Calculate the old hash for the ip address only, when the current one mismatches

master
Dirk Engling 9 years ago
parent
commit
d010868308
  1. 43
      ot_udp.c

43
ot_udp.c

@ -35,22 +35,20 @@ static void udp_generate_rijndael_round_key() {
}
/* Generate current and previous connection id for ip */
static void udp_make_connectionid( uint32_t connid[4], const ot_ip6 remoteip ) {
static void udp_make_connectionid( uint32_t connid[2], const ot_ip6 remoteip, int age ) {
uint32_t plain[4], crypt[4];
int age, i;
int i;
if( g_now_minutes + 60 > g_hour_of_the_key ) {
g_hour_of_the_key = g_now_minutes;
g_key_of_the_hour[1] = g_key_of_the_hour[0];
g_key_of_the_hour[0] = random();
}
for( age = 0; age < 1; ++age ) {
memcpy( plain, remoteip, sizeof( plain ) );
for( i=0; i<4; ++i ) plain[i] ^= g_key_of_the_hour[age];
rijndaelEncrypt128( g_rijndael_round_key, (uint8_t*)remoteip, (uint8_t*)crypt );
connid[2*age ] = crypt[0] ^ crypt[1];
connid[2*age+1] = crypt[2] ^ crypt[3];
}
memcpy( plain, remoteip, sizeof( plain ) );
for( i=0; i<4; ++i ) plain[i] ^= g_key_of_the_hour[age];
rijndaelEncrypt128( g_rijndael_round_key, (uint8_t*)remoteip, (uint8_t*)crypt );
connid[0] = crypt[0] ^ crypt[1];
connid[1] = crypt[2] ^ crypt[3];
}
/* UDP implementation according to http://xbtt.sourceforge.net/udp_tracker_protocol.html */
@ -59,7 +57,7 @@ int handle_udp6( int64 serversocket, struct ot_workstruct *ws ) {
uint32_t *inpacket = (uint32_t*)ws->inbuf;
uint32_t *outpacket = (uint32_t*)ws->outbuf;
uint32_t numwant, left, event, scopeid;
uint32_t connid[4];
uint32_t connid[2];
uint16_t port, remoteport;
size_t byte_count, scrape_count;
@ -75,7 +73,7 @@ int handle_udp6( int64 serversocket, struct ot_workstruct *ws ) {
/* Generate the connection id we give out and expect to and from
the requesting ip address, this prevents udp spoofing */
udp_make_connectionid( connid, remoteip );
udp_make_connectionid( connid, remoteip, 0 );
/* Initialise hash pointer */
ws->hash = NULL;
@ -83,14 +81,19 @@ int handle_udp6( int64 serversocket, struct ot_workstruct *ws ) {
/* If action is not a ntohl(a) == a == 0, then we
expect the derived connection id in first 64 bit */
if( inpacket[2] && ( inpacket[0] != connid[0] || inpacket[1] != connid[1] ) &&
( inpacket[0] != connid[2] || inpacket[1] != connid[3] ) ) {
const size_t s = sizeof( "Connection ID missmatch." );
outpacket[0] = 3; outpacket[1] = inpacket[3];
memcpy( &outpacket[2], "Connection ID missmatch.", s );
socket_send6( serversocket, ws->outbuf, 8 + s, remoteip, remoteport, 0 );
stats_issue_event( EVENT_CONNID_MISSMATCH, FLAG_UDP, 8 + s );
return 1;
if( inpacket[2] && ( inpacket[0] != connid[0] || inpacket[1] != connid[1] ) ) {
/* If connection id does not match, try the one that was
valid in the previous hour. Only if this also does not
match, return an error packet */
udp_make_connectionid( connid, remoteip, 1 );
if( inpacket[0] != connid[0] || inpacket[1] != connid[1] ) {
const size_t s = sizeof( "Connection ID missmatch." );
outpacket[0] = 3; outpacket[1] = inpacket[3];
memcpy( &outpacket[2], "Connection ID missmatch.", s );
socket_send6( serversocket, ws->outbuf, 8 + s, remoteip, remoteport, 0 );
stats_issue_event( EVENT_CONNID_MISSMATCH, FLAG_UDP, 8 + s );
return 1;
}
}
switch( ntohl( inpacket[2] ) ) {
@ -197,4 +200,4 @@ void udp_init( int64 sock, unsigned int worker_count ) {
pthread_create( &thread_id, NULL, udp_worker, (void *)sock );
}
const char *g_version_udp_c = "$Source: /home/cvsroot/opentracker/ot_udp.c,v $: $Revision: 1.29 $\n";
const char *g_version_udp_c = "$Source: /home/cvsroot/opentracker/ot_udp.c,v $: $Revision: 1.30 $\n";
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