// . use msg 0x55 to say you are done using the proxy
// . we now use the top part of the Msg13Request as the proxy request
void returnProxy ( Msg13Request *preq , UdpSlot *udpSlot ) {
//char *p = request;
//int32_t proxyIp = *(int32_t *)p; p += 4;
//int16_t proxyPort = *(int16_t *)p; p += 2;
//int32_t lbId = *(int32_t *)p; p += 4;
int32_t urlIp = preq->m_urlIp;
//
// update the load bucket
//
// scan over all that match to find lbid
int32_t hslot = s_loadTable.getSlot ( &urlIp );
// scan all proxies that have this urlip outstanding
int32_t i;for (i=hslot ; i >= 0 ; i = s_loadTable.getNextSlot(i,&urlIp)){
// get the bucket
LoadBucket *lb= (LoadBucket *)s_loadTable.getValueFromSlot(i);
// is it the right id?
if ( lb->m_id != preq->m_lbId ) continue;
if ( lb->m_proxyIp != preq->m_proxyIp ) continue;
if ( lb->m_proxyPort != preq->m_proxyPort ) continue;
// that's it. set the download end time
int64_t nowms = gettimeofdayInMillisecondsLocal();
lb->m_downloadEndTimeMS = nowms;
break;
}
if ( i < 0 )
log("sproxy: could not find load bucket id #%" PRId32,preq->m_lbId);
// if no slot provided, return to called without sending back reply,
// they are banning a proxy and need to also return it before
// we send them back another proxy to try.
if ( ! udpSlot ) return;
// gotta send reply back
g_udpServer.sendReply(0, 0, 0, 0, udpSlot);
}
// a host is asking us (host #0) what proxy to use?
static void handleRequest54(UdpSlot *udpSlot, int32_t niceness) {
char *request = udpSlot->m_readBuf;
int32_t requestSize = udpSlot->m_readBufSize;
// we now use the top part of the Msg13Request as the ProxyRequest
Msg13Request *preq = (Msg13Request *)request;
// sanity check
if ( requestSize != preq->getProxyRequestSize() ) {
log("db: Got bad request 0x54 size of %" PRId32" bytes. bad",
requestSize );
g_udpServer.sendErrorReply ( udpSlot , EBADREQUESTSIZE );
return;
}
// is the request telling us it is done downloading through a proxy?
if ( preq->m_opCode == OP_RETPROXY ) {
returnProxy ( preq , udpSlot );
return;
}
// if sender is asking for a new proxy and wants us to ban
// the previous proxy we sent for this urlIp...
if ( preq->m_banProxyIp ) {
// don't core if misses sanity. it seems we don't always
// NULLify these or something.
// these must match
if(preq->m_banProxyIp != preq->m_proxyIp ||
preq->m_banProxyPort != preq->m_proxyPort){
log("db: proxy: banproxyip != proxyip. mismatch!");
g_udpServer.sendErrorReply ( udpSlot , EBADENGINEER);
return;
}
// this will "return" the banned proxy
returnProxy ( preq , NULL );
// now add it to the banned table
int64_t uip = preq->m_urlIp;
int64_t pip = preq->m_banProxyIp;
int64_t h64 = hash64h ( uip , pip );
if ( ! s_proxyBannedTable.isInTable ( &h64 ) ) {
s_proxyBannedTable.addKey ( &h64 );
// for stats counting. each proxy ip maps to #
// of unique website IPs that have banned it.
s_banCountTable.addTerm32((uint32_t)pip);
}
}
// shortcut
int32_t urlIp = preq->m_urlIp;
// send to a proxy that is up and has the least amount
// of LoadBuckets with this urlIp, if tied, go to least loaded.
// clear counts for this url ip for scoring the best proxy to use
for ( int32_t i = 0 ; i < s_iptab.getNumSlots() ; i++ ) {
// skip empty slots
if ( ! s_iptab.m_flags[i] ) continue;
SpiderProxy *sp = (SpiderProxy *)s_iptab.getValueFromSlot(i);
sp->m_countForThisIp = 0;
sp->m_lastTimeUsedForThisIp = 0LL;
}
// this table maps a url's current IP to a possibly MULTIPLE slots
// which tell us what proxy is downloading a page from that IP.
// so we can try to find a proxy that is not download a url from
// this IP currently, or hasn't been for the longest time...
int32_t hslot = s_loadTable.getSlot ( &urlIp );
// scan all proxies that have this urlip outstanding
for ( int32_t i = hslot ; i >= 0 ; i = s_loadTable.getNextSlot(i,&urlIp)){
// get the bucket
LoadBucket *lb;
lb = (LoadBucket *)s_loadTable.getValueFromSlot(i);
// get the spider proxy this load point was for
uint64_t key = (uint32_t)lb->m_proxyIp;
key <<= 16;
key |= (uint16_t)lb->m_proxyPort;
SpiderProxy *sp = (SpiderProxy *)s_iptab.getValue(&key);
// must be there unless user remove it from the list
if ( ! sp ) continue;
// count it up
if ( lb->m_downloadEndTimeMS == 0LL )
sp->m_countForThisIp++;
// set the last time used to the most recently downloaded time
// that this proxy has downloaded from this ip
if ( lb->m_downloadEndTimeMS &&
lb->m_downloadEndTimeMS > sp->m_lastTimeUsedForThisIp )
sp->m_lastTimeUsedForThisIp = lb->m_downloadEndTimeMS;
}
// first try to get a spider proxy that is not "dead"
bool skipDead = true;
int32_t numBannedProxies = 0;
int32_t aliveProxyCandidates = 0;
redo:
// get the min of the counts
int32_t minCount = 999999;
for ( int32_t i = 0 ; i < s_iptab.getNumSlots() ; i++ ) {
// skip empty slots
if ( ! s_iptab.m_flags[i] ) continue;
// get the spider proxy
SpiderProxy *sp = (SpiderProxy *)s_iptab.getValueFromSlot(i);
// if this proxy was banned by the url's ip... skip it. it is
// not a candidate...
if ( skipDead ) {
int64_t uip = preq->m_urlIp;
int64_t pip = sp->m_ip;
int64_t h64 = hash64h ( uip , pip );
if ( s_proxyBannedTable.isInTable ( &h64 ) ) {
numBannedProxies++;
continue;
}
}
// if it failed the last test, skip it
if ( skipDead && sp->m_lastDownloadError ) continue;
if ( skipDead ) aliveProxyCandidates++;
if ( sp->m_countForThisIp >= minCount ) continue;
minCount = sp->m_countForThisIp;
}
// all dead? then get the best dead one
if ( minCount == 999999 ) {
skipDead = false;
goto redo;
}
// . we only use one proxy if none are banned by this IP
// . when that gets banned, we will use the next 2 proxies with
// a higher backoff/crawlDelay, etc.
int32_t threshHold;
if ( numBannedProxies <= 0 ) threshHold = 1;
// if first proxy gets banned, try next 2 proxies until both get ban'd
else if ( numBannedProxies == 1 ) threshHold = 2;
else if ( numBannedProxies < 1+2) threshHold = 3 - numBannedProxies;
// if next two proxies got banned, try next 4 proxies until banned
else if ( numBannedProxies == 3 ) threshHold = 4;
else if ( numBannedProxies < 3+4) threshHold = 7 - numBannedProxies;
// if next 4 proxies got banned, try next 8 proxies until they get band
else if ( numBannedProxies == 7 ) threshHold = 8;
else if ( numBannedProxies < 7+8) threshHold = 15 - numBannedProxies;
else if ( numBannedProxies == 15) threshHold = 16;
else if ( numBannedProxies < 15+16 ) threshHold = 31-numBannedProxies;
else if ( numBannedProxies == 31 ) threshHold = 32;
else if ( numBannedProxies < 31+32)threshHold=63-numBannedProxies;
else if ( numBannedProxies == 63 ) threshHold = 64;
else if ( numBannedProxies < 63+64)threshHold=127-numBannedProxies;
else if ( numBannedProxies == 127 ) threshHold = 128;
else if ( numBannedProxies < 127+128)threshHold=255-numBannedProxies;
else if ( numBannedProxies == 255 ) threshHold = 256;
else if ( numBannedProxies < 255+256)threshHold=512-numBannedProxies;
else if ( numBannedProxies == 511 ) threshHold = 512;
else if ( numBannedProxies < 511+512)threshHold=1024-numBannedProxies;
else threshHold = 1024;
if ( threshHold <= 0 ) {
log("proxy: spiderproxy error in threshold of %" PRId32" "
"for banned=%" PRId32,threshHold,numBannedProxies);
threshHold = 1;
}
// reset minCount so we can take the min over those we check here
minCount = -1;
int64_t oldest = 0x7fffffffffffffffLL;
SpiderProxy *winnersp = NULL;
int32_t count = 0;
// start at a random slot based on url's IP so we don't
// overload the first proxy
int32_t start = ((uint32_t)urlIp) % s_iptab.getNumSlots();
int32_t slotCount = s_iptab.getNumSlots();
// . now find the best proxy wih the minCount
for ( int32_t i = start ; ; i++ ) {
// scan all slots in hash table, then stop
if ( slotCount-- <= 0 ) break;
// wrap around to zero if we hit the end
if ( i == s_iptab.getNumSlots() ) i = 0;
// skip empty slots
if ( ! s_iptab.m_flags[i] ) continue;
// get the spider proxy
SpiderProxy *sp = (SpiderProxy *)s_iptab.getValueFromSlot(i);
// if it failed the last test, skip it... not here...
if ( skipDead && sp->m_lastDownloadError ) continue;
// if this proxy was banned by the url's ip... skip it. it is
// not a candidate...
if ( skipDead ) {
int64_t uip = preq->m_urlIp;
int64_t pip = sp->m_ip;
int64_t h64 = hash64h ( uip , pip );
if ( s_proxyBannedTable.isInTable ( &h64 ) ) continue;
}
// if some proxies are "alive" then only pick from
// the first half of the proxies that are alive (i.e. still
// work). that way, when one of those goes dead we will inc
// the backoff (crawldelay) and a new proxy that we haven't
// used for this url's IP will take it's place. and such
// new proxies will only have the new backoff count used
// through them. that way, we don't get ALL of our proxies
// banned at about the same time since we do somewhat uniform
// load balancing over them.
if ( skipDead && count >= threshHold)//aliveProxyCandidates/2 )
continue;
// count the alive/non-banned candidates
count++;
// if all hosts were "dead" because they all had
// m_lastDownloadError set then minCount will be 999999
// and nobody should continue from this statement:
if ( sp->m_countForThisIp > minCount && minCount>=0 ) continue;
// then go by last download time for this ip
if ( sp->m_countForThisIp == minCount && minCount>=0 &&
sp->m_lastTimeUsedForThisIp >= oldest )
continue;
// pick the spider proxy used longest ago
oldest = sp->m_lastTimeUsedForThisIp;
minCount = sp->m_countForThisIp;
// got a new winner
winnersp = sp;
}
// we must have a winner
if ( ! winnersp ) { g_process.shutdownAbort(true); }
int64_t nowms = gettimeofdayInMillisecondsLocal();
// add a new load bucket then!
LoadBucket bb;
bb.m_urlIp = urlIp;
// the time it started
bb.m_downloadStartTimeMS = nowms;
// download has not ended yet
bb.m_downloadEndTimeMS = 0LL;
// the host using the proxy
bb.m_hostId = udpSlot->getHostId();
// key is this for m_prTable
bb.m_proxyIp = winnersp->m_ip;
bb.m_proxyPort = winnersp->m_port;
// a new id. we use this to update the downloadEndTime when done
static int32_t s_lbid = 0;
// add it now
bb.m_id = s_lbid++;
s_loadTable.addKey ( &urlIp , &bb );
// winner count update
winnersp->m_timesUsed++;
// sanity
if ( (int32_t)sizeof(ProxyReply) > TMPBUFSIZE ){g_process.shutdownAbort(true);}
// and give proxy ip/port back to the requester so they can
// use that to download their url
ProxyReply *prep = (ProxyReply *)udpSlot->m_tmpBuf;
prep->m_proxyIp = winnersp->m_ip;
prep->m_proxyPort = winnersp->m_port;
// this is just '\0' if none
strcpy(prep->m_usernamePwd,winnersp->m_usernamePwd);
// do not count the proxy we are returning as "more"
prep->m_hasMoreProxiesToTry = ( aliveProxyCandidates > 1 );
// and the loadbucket id, so requester can tell us it is done
// downloading through the proxy and we can update the LoadBucket
// for this transaction (m_lbId)
prep->m_lbId = bb.m_id;
// requester wants to know how many proxies have been banned by the
// urlIp so it can increase a self-imposed crawl-delay to be more
// sensitive to the spider policy.
prep->m_numBannedProxies = numBannedProxies;
//char *p = udpSlot->m_tmpBuf;
//*(int32_t *)p = winnersp->m_ip ; p += 4;
//*(int16_t *)p = winnersp->m_port; p += 2;
// and the loadbucket id
//*(int32_t *)p = bb.m_id; p += 4;
// with dup keys we end up with long chains of crap and this
// takes forever. so just flush the whole thing every 2 minutes AND
// when 20000+ entries are in there
static time_t s_lastTime = 0;
time_t now = nowms / 1000;
if ( s_lastTime == 0 ) s_lastTime = now;
time_t elapsed = now - s_lastTime;
if ( elapsed > 120 && s_loadTable.getNumSlots() > 10000 ) {
log("sproxy: flushing %i entries from proxy loadtable that "
"have accumulated since %i seconds ago",
(int)s_loadTable.m_numSlotsUsed,(int)elapsed);
s_loadTable.clear();
// only do this one per minute
s_lastTime = now;
}
int32_t sanityCount = 0;//s_loadTable.getNumSlots();
// top:
// now remove old entries from the load table. entries that
// have completed and have a download end time more than 10 mins ago.
for ( int32_t i = s_loadTable.getNumSlots() - 1 ; i >= 0 ; i-- ) {
// skip if empty
if ( ! s_loadTable.m_flags[i] ) continue;
// get the bucket
LoadBucket *pp =(LoadBucket *)s_loadTable.getValueFromSlot(i);
// skip if still active
if ( pp->m_downloadEndTimeMS == 0LL ) continue;
// delta t
int64_t took = nowms - pp->m_downloadEndTimeMS;
// < 10 mins? now it's < 15 seconds to prevent clogging.
if ( took < LOADPOINT_EXPIRE_MS ) continue;
// 100 at a time so we don't slam cpu
if ( sanityCount++ > 100 ) break;
// ok, its too old, nuke it to save memory
s_loadTable.removeSlot(i);
// the keys might have buried us but we really should not
// mis out on analyzing any keys if we just keep looping here
// should we? TODO: figure it out. if we miss a few it's not
// a big deal.
//i--;
//goto top;
}
// send the proxy ip/port/LBid back to user
g_udpServer.sendReply(udpSlot->m_tmpBuf, sizeof(ProxyReply), udpSlot->m_tmpBuf, sizeof(ProxyReply), udpSlot);
}