@ -161,65 +161,92 @@ void Topology::saveIdentity(const Identity &id)
SharedPtr < Peer > Topology : : getBestSupernode ( const Address * avoid , unsigned int avoidCount , bool strictAvoid ) const
{
SharedPtr < Peer > bestSupernode ;
unsigned int l , bestSupernodeLatency = 65536 ;
uint64_t now = Utils : : now ( ) ;
uint64_t lds , ldr ;
Mutex : : Lock _l ( _supernodes_m ) ;
// First look for a best supernode by comparing latencies, but exclude
// supernodes that have not responded to direct messages in order to
// try to exclude any that are dead or unreachable.
for ( std : : vector < SharedPtr < Peer > > : : const_iterator sn ( _supernodePeers . begin ( ) ) ; sn ! = _supernodePeers . end ( ) ; ) {
// Skip explicitly avoided relays
for ( unsigned int i = 0 ; i < avoidCount ; + + i ) {
if ( avoid [ i ] = = ( * sn ) - > address ( ) )
goto keep_searching_for_supernodes ;
if ( _amSupernode ) {
/* If I am a supernode, the "best" supernode is the one whose address
* is numerically greater than mine ( with wrap at top of list ) . This
* causes packets searching for a route to pretty much literally
* circumnavigate the globe rather than bouncing between just two . */
if ( _supernodeAddresses . size ( ) > 1 ) { // gotta be one other than me for this to work
std : : set < Address > : : const_iterator sna ( _supernodeAddresses . find ( _r - > identity . address ( ) ) ) ;
if ( sna ! = _supernodeAddresses . end ( ) ) { // sanity check -- _amSupernode should've been false in this case
for ( ; ; ) {
if ( + + sna = = _supernodeAddresses . end ( ) )
sna = _supernodeAddresses . begin ( ) ; // wrap around at end
if ( * sna ! = _r - > identity . address ( ) ) { // pick one other than us -- starting from me+1 in sorted set order
SharedPtr < Peer > p ( getPeer ( * sna ) ) ;
if ( ( p ) & & ( p - > hasActiveDirectPath ( now ) ) ) {
bestSupernode = p ;
break ;
}
}
}
}
}
} else {
/* If I am not a supernode, the best supernode is the active one with
* the lowest latency . */
unsigned int l , bestSupernodeLatency = 65536 ;
uint64_t lds , ldr ;
// First look for a best supernode by comparing latencies, but exclude
// supernodes that have not responded to direct messages in order to
// try to exclude any that are dead or unreachable.
for ( std : : vector < SharedPtr < Peer > > : : const_iterator sn ( _supernodePeers . begin ( ) ) ; sn ! = _supernodePeers . end ( ) ; ) {
// Skip explicitly avoided relays
for ( unsigned int i = 0 ; i < avoidCount ; + + i ) {
if ( avoid [ i ] = = ( * sn ) - > address ( ) )
goto keep_searching_for_supernodes ;
}
// Skip possibly comatose or unreachable relays
lds = ( * sn ) - > lastDirectSend ( ) ;
ldr = ( * sn ) - > lastDirectReceive ( ) ;
if ( ( lds ) & & ( lds > ldr ) & & ( ( lds - ldr ) > ZT_PEER_RELAY_CONVERSATION_LATENCY_THRESHOLD ) )
goto keep_searching_for_supernodes ;
// Skip possibly comatose or unreachable relays
lds = ( * sn ) - > lastDirectSend ( ) ;
ldr = ( * sn ) - > lastDirectReceive ( ) ;
if ( ( lds ) & & ( lds > ldr ) & & ( ( lds - ldr ) > ZT_PEER_RELAY_CONVERSATION_LATENCY_THRESHOLD ) )
goto keep_searching_for_supernodes ;
if ( ( * sn ) - > hasActiveDirectPath ( now ) ) {
l = ( * sn ) - > latency ( ) ;
if ( bestSupernode ) {
if ( ( l ) & & ( l < bestSupernodeLatency ) ) {
bestSupernodeLatency = l ;
if ( ( * sn ) - > hasActiveDirectPath ( now ) ) {
l = ( * sn ) - > latency ( ) ;
if ( bestSupernode ) {
if ( ( l ) & & ( l < bestSupernodeLatency ) ) {
bestSupernodeLatency = l ;
bestSupernode = * sn ;
}
} else {
if ( l )
bestSupernodeLatency = l ;
bestSupernode = * sn ;
}
} else {
if ( l )
bestSupernodeLatency = l ;
bestSupernode = * sn ;
}
}
keep_searching_for_supernodes :
+ + sn ;
}
if ( bestSupernode ) {
bestSupernode - > use ( now ) ;
return bestSupernode ;
} else if ( strictAvoid )
return SharedPtr < Peer > ( ) ;
+ + sn ;
}
// If we have nothing from above, just pick one without avoidance criteria.
for ( std : : vector < SharedPtr < Peer > > : : const_iterator sn = _supernodePeers . begin ( ) ; sn ! = _supernodePeers . end ( ) ; + + sn ) {
if ( ( * sn ) - > hasActiveDirectPath ( now ) ) {
unsigned int l = ( * sn ) - > latency ( ) ;
if ( bestSupernode ) {
if ( ( l ) & & ( l < bestSupernodeLatency ) ) {
bestSupernodeLatency = l ;
if ( bestSupernode ) {
bestSupernode - > use ( now ) ;
return bestSupernode ;
} else if ( strictAvoid )
return SharedPtr < Peer > ( ) ;
// If we have nothing from above, just pick one without avoidance criteria.
for ( std : : vector < SharedPtr < Peer > > : : const_iterator sn = _supernodePeers . begin ( ) ; sn ! = _supernodePeers . end ( ) ; + + sn ) {
if ( ( * sn ) - > hasActiveDirectPath ( now ) ) {
unsigned int l = ( * sn ) - > latency ( ) ;
if ( bestSupernode ) {
if ( ( l ) & & ( l < bestSupernodeLatency ) ) {
bestSupernodeLatency = l ;
bestSupernode = * sn ;
}
} else {
if ( l )
bestSupernodeLatency = l ;
bestSupernode = * sn ;
}
} else {
if ( l )
bestSupernodeLatency = l ;
bestSupernode = * sn ;
}
}
}
Adam Ierymenko
12 years ago