mirror of https://github.com/DrBeef/ioq3quest.git
* Rate limit getstatus and rcon connectionless requests
This commit is contained in:
Tim Angus
parent
e7f9b8d193
commit
4056c90358
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@ -351,6 +351,182 @@ CONNECTIONLESS COMMANDS
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==============================================================================
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*/
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typedef struct leakyBucket_s leakyBucket_t;
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struct leakyBucket_s {
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netadrtype_t type;
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union {
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byte _4[4];
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byte _6[16];
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} ipv;
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int lastTime;
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signed char burst;
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long hash;
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leakyBucket_t *prev, *next;
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};
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// This is deliberately quite large to make it more of an effort to DoS
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#define MAX_BUCKETS 16384
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#define MAX_HASHES 1024
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static leakyBucket_t buckets[ MAX_BUCKETS ];
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static leakyBucket_t *bucketHashes[ MAX_HASHES ];
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/*
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================
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SVC_HashForAddress
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================
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*/
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static long SVC_HashForAddress( netadr_t address ) {
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byte *ip;
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size_t size;
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int i;
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long hash = 0;
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switch ( address.type ) {
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case NA_IP: ip = address.ip; size = 4; break;
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case NA_IP6: ip = address.ip6; size = 16; break;
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default: break;
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}
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for ( i = 0; i < size; i++ ) {
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hash += (long)( ip[ i ] ) * ( i + 119 );
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}
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hash = ( hash ^ ( hash >> 10 ) ^ ( hash >> 20 ) );
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hash &= ( MAX_HASHES - 1 );
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return hash;
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}
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/*
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================
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SVC_BucketForAddress
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Find or allocate a bucket for an address
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================
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*/
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static leakyBucket_t *SVC_BucketForAddress( netadr_t address, int burst, int period ) {
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leakyBucket_t *bucket = NULL;
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int i;
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long hash = SVC_HashForAddress( address );
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int now = Sys_Milliseconds();
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for ( bucket = bucketHashes[ hash ]; bucket; bucket = bucket->next ) {
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switch ( bucket->type ) {
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case NA_IP:
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if ( memcmp( bucket->ipv._4, address.ip, 4 ) == 0 ) {
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return bucket;
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}
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break;
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case NA_IP6:
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if ( memcmp( bucket->ipv._6, address.ip6, 16 ) == 0 ) {
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return bucket;
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}
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break;
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default:
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break;
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}
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}
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for ( i = 0; i < MAX_BUCKETS; i++ ) {
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int interval;
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bucket = &buckets[ i ];
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interval = now - bucket->lastTime;
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// Reclaim expired buckets
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if ( bucket->lastTime > 0 && interval > ( burst * period ) ) {
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if ( bucket->prev != NULL ) {
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bucket->prev->next = bucket->next;
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} else {
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bucketHashes[ bucket->hash ] = bucket->next;
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}
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if ( bucket->next != NULL ) {
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bucket->next->prev = bucket->prev;
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}
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Com_Memset( bucket, 0, sizeof( leakyBucket_t ) );
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}
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if ( bucket->type == NA_BAD ) {
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bucket->type = address.type;
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switch ( address.type ) {
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case NA_IP: Com_Memcpy( bucket->ipv._4, address.ip, 4 ); break;
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case NA_IP6: Com_Memcpy( bucket->ipv._6, address.ip6, 16 ); break;
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default: break;
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}
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bucket->lastTime = now;
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bucket->burst = 0;
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bucket->hash = hash;
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// Add to the head of the relevant hash chain
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bucket->next = bucketHashes[ hash ];
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if ( bucketHashes[ hash ] != NULL ) {
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bucketHashes[ hash ]->prev = bucket;
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}
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bucket->prev = NULL;
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bucketHashes[ hash ] = bucket;
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return bucket;
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}
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}
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// Couldn't allocate a bucket for this address
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return NULL;
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}
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/*
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================
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SVC_RateLimit
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================
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*/
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static qboolean SVC_RateLimit( leakyBucket_t *bucket, int burst, int period ) {
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if ( bucket != NULL ) {
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int now = Sys_Milliseconds();
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int interval = now - bucket->lastTime;
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int expired = interval / period;
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int expiredRemainder = interval % period;
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if ( expired > bucket->burst ) {
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bucket->burst = 0;
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bucket->lastTime = now;
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} else {
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bucket->burst -= expired;
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bucket->lastTime = now - expiredRemainder;
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}
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if ( bucket->burst < burst ) {
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bucket->burst++;
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return qfalse;
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}
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}
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return qtrue;
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}
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/*
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================
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SVC_RateLimitAddress
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Rate limit for a particular address
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================
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*/
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static qboolean SVC_RateLimitAddress( netadr_t from, int burst, int period ) {
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leakyBucket_t *bucket = SVC_BucketForAddress( from, burst, period );
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return SVC_RateLimit( bucket, burst, period );
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}
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/*
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================
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SVC_Status
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@ -369,12 +545,27 @@ static void SVC_Status( netadr_t from ) {
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int statusLength;
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int playerLength;
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char infostring[MAX_INFO_STRING];
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static leakyBucket_t bucket;
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// ignore if we are in single player
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if ( Cvar_VariableValue( "g_gametype" ) == GT_SINGLE_PLAYER ) {
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return;
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}
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// Prevent using getstatus as an amplifier
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if ( SVC_RateLimitAddress( from, 10, 1000 ) ) {
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Com_DPrintf( "SVC_Status: rate limit from %s exceeded, dropping request\n",
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NET_AdrToString( from ) );
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return;
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}
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// Allow getstatus to be DoSed relatively easily, but prevent
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// excess outbound bandwidth usage when being flooded inbound
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if ( SVC_RateLimit( &bucket, 10, 100 ) ) {
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Com_DPrintf( "SVC_Status: rate limit exceeded, dropping request\n" );
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return;
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}
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strcpy( infostring, Cvar_InfoString( CVAR_SERVERINFO ) );
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// echo back the parameter to status. so master servers can use it as a challenge
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@ -493,24 +684,30 @@ Redirect all printfs
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*/
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static void SVC_RemoteCommand( netadr_t from, msg_t *msg ) {
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qboolean valid;
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unsigned int time;
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char remaining[1024];
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// TTimo - scaled down to accumulate, but not overflow anything network wise, print wise etc.
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// (OOB messages are the bottleneck here)
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#define SV_OUTPUTBUF_LENGTH (1024 - 16)
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char sv_outputbuf[SV_OUTPUTBUF_LENGTH];
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static unsigned int lasttime = 0;
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char *cmd_aux;
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// TTimo - https://zerowing.idsoftware.com/bugzilla/show_bug.cgi?id=534
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time = Com_Milliseconds();
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if ( (unsigned)( time - lasttime ) < 500u ) {
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// Prevent using rcon as an amplifier and make dictionary attacks impractical
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if ( SVC_RateLimitAddress( from, 10, 1000 ) ) {
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Com_DPrintf( "SVC_Status: rate limit from %s exceeded, dropping request\n",
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NET_AdrToString( from ) );
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return;
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}
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lasttime = time;
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if ( !strlen( sv_rconPassword->string ) ||
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strcmp (Cmd_Argv(1), sv_rconPassword->string) ) {
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static leakyBucket_t bucket;
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// Make DoS via rcon impractical
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if ( SVC_RateLimit( &bucket, 10, 1000 ) ) {
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Com_DPrintf( "SVC_Status: rate limit exceeded, dropping request\n" );
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return;
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}
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valid = qfalse;
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Com_Printf ("Bad rcon from %s: %s\n", NET_AdrToString (from), Cmd_ArgsFrom(2) );
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} else {
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@ -579,7 +776,7 @@ static void SV_ConnectionlessPacket( netadr_t from, msg_t *msg ) {
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Com_DPrintf ("SV packet %s : %s\n", NET_AdrToString(from), c);
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if (!Q_stricmp(c, "getstatus")) {
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SVC_Status( from );
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SVC_Status( from );
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} else if (!Q_stricmp(c, "getinfo")) {
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SVC_Info( from );
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} else if (!Q_stricmp(c, "getchallenge")) {
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@ -597,8 +794,8 @@ static void SV_ConnectionlessPacket( netadr_t from, msg_t *msg ) {
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// server disconnect messages when their new server sees our final
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// sequenced messages to the old client
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} else {
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Com_DPrintf ("bad connectionless packet from %s:\n%s\n"
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, NET_AdrToString (from), s);
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Com_DPrintf ("bad connectionless packet from %s:\n%s\n",
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NET_AdrToString (from), s);
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}
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}
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@ -606,7 +803,7 @@ static void SV_ConnectionlessPacket( netadr_t from, msg_t *msg ) {
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/*
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=================
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SV_ReadPackets
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SV_PacketEvent
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=================
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*/
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void SV_PacketEvent( netadr_t from, msg_t *msg ) {
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