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

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erdgeist 2012-06-03 00:17:07 +00:00
parent 7e2bef9bf7
commit 8741c91a7d
1 changed files with 22 additions and 19 deletions
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41
ot_udp.c
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@ -35,22 +35,20 @@ static void udp_generate_rijndael_round_key() {
} }
/* Generate current and previous connection id for ip */ /* 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]; uint32_t plain[4], crypt[4];
int age, i; int i;
if( g_now_minutes + 60 > g_hour_of_the_key ) { if( g_now_minutes + 60 > g_hour_of_the_key ) {
g_hour_of_the_key = g_now_minutes; 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[1] = g_key_of_the_hour[0];
g_key_of_the_hour[0] = random(); g_key_of_the_hour[0] = random();
} }
for( age = 0; age < 1; ++age ) { memcpy( plain, remoteip, sizeof( plain ) );
memcpy( plain, remoteip, sizeof( plain ) ); for( i=0; i<4; ++i ) plain[i] ^= g_key_of_the_hour[age];
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 );
rijndaelEncrypt128( g_rijndael_round_key, (uint8_t*)remoteip, (uint8_t*)crypt ); connid[0] = crypt[0] ^ crypt[1];
connid[2*age ] = crypt[0] ^ crypt[1]; connid[1] = crypt[2] ^ crypt[3];
connid[2*age+1] = crypt[2] ^ crypt[3];
}
} }
/* UDP implementation according to http://xbtt.sourceforge.net/udp_tracker_protocol.html */ /* 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 *inpacket = (uint32_t*)ws->inbuf;
uint32_t *outpacket = (uint32_t*)ws->outbuf; uint32_t *outpacket = (uint32_t*)ws->outbuf;
uint32_t numwant, left, event, scopeid; uint32_t numwant, left, event, scopeid;
uint32_t connid[4]; uint32_t connid[2];
uint16_t port, remoteport; uint16_t port, remoteport;
size_t byte_count, scrape_count; 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 /* Generate the connection id we give out and expect to and from
the requesting ip address, this prevents udp spoofing */ the requesting ip address, this prevents udp spoofing */
udp_make_connectionid( connid, remoteip ); udp_make_connectionid( connid, remoteip, 0 );
/* Initialise hash pointer */ /* Initialise hash pointer */
ws->hash = NULL; 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 /* If action is not a ntohl(a) == a == 0, then we
expect the derived connection id in first 64 bit */ expect the derived connection id in first 64 bit */
if( inpacket[2] && ( inpacket[0] != connid[0] || inpacket[1] != connid[1] ) && if( inpacket[2] && ( inpacket[0] != connid[0] || inpacket[1] != connid[1] ) ) {
( inpacket[0] != connid[2] || inpacket[1] != connid[3] ) ) { /* If connection id does not match, try the one that was
const size_t s = sizeof( "Connection ID missmatch." ); valid in the previous hour. Only if this also does not
outpacket[0] = 3; outpacket[1] = inpacket[3]; match, return an error packet */
memcpy( &outpacket[2], "Connection ID missmatch.", s ); udp_make_connectionid( connid, remoteip, 1 );
socket_send6( serversocket, ws->outbuf, 8 + s, remoteip, remoteport, 0 ); if( inpacket[0] != connid[0] || inpacket[1] != connid[1] ) {
stats_issue_event( EVENT_CONNID_MISSMATCH, FLAG_UDP, 8 + s ); const size_t s = sizeof( "Connection ID missmatch." );
return 1; 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] ) ) { switch( ntohl( inpacket[2] ) ) {