Improved ShareLimiter

src/server/poolserver/Main.cpp

@@ -48,9 +48,11 @@ bool InitConfig(int argc, char *argv[])
         ("StratumPort,sp", boost::program_options::value<uint16_t>()->default_value(3333), "Stratum server port")
         ("StratumBlockCheckTime", boost::program_options::value<uint32>()->default_value(2000), "Time between block checks in ms")
         ("RetargetInterval", boost::program_options::value<uint32>()->default_value(20), "Time between difficulty checks in seconds")
+        ("RetargetSharesThreashold", boost::program_options::value<uint32>()->default_value(20), "Number of shares in retarget interval to trigger a difficulty check")
         ("RetargetTimeBuffer", boost::program_options::value<uint32>()->default_value(60*5), "Buffer of shares to keep (in seconds)")
-        ("RetargetTimePerShare", boost::program_options::value<double>()->default_value(10), "Target in seconds between shares")
+        ("RetargetTimePerShare", boost::program_options::value<double>()->default_value(4), "Target in seconds between shares")
         ("RetargetVariance", boost::program_options::value<uint32>()->default_value(40), "Maximum allowed variance in percent before difficulty change")
+        ("RetargetStartingDiff", boost::program_options::value<uint32>()->default_value(2), "Difficulty at which new miner starts")
         ("RetargetMinDiff", boost::program_options::value<uint32>()->default_value(1), "Minimum difficulty (also starting difficulty)")
         ("RetargetMaxDiff", boost::program_options::value<uint32>()->default_value(1000000), "Maximum difficulty we can reach")
     ;

src/server/poolserver/Stratum/Client.cpp

@@ -37,9 +37,9 @@ namespace Stratum
     void Client::SendJob(bool clean)
     {
         if (clean)
-            _jobs.clear();
+            CleanJobs();
         
-        Job job = GetJob();
+        Job* job = GetJob();
         uint32 jobid = _jobid++;
         
         _jobs[jobid] = job;
@@ -51,14 +51,14 @@ namespace Stratum
         JSON merkle_branch(JSON_ARRAY);
         
         uint32 j = 0;
-        for (uint32 size = job.block->tx.size(); size > 1; size = (size+1)/2)
+        for (uint32 size = job->block->tx.size(); size > 1; size = (size+1)/2)
         {
-            merkle_branch.Add(Util::BinToASCII(job.block->merkleTree[j+1]));
+            merkle_branch.Add(Util::BinToASCII(job->block->merkleTree[j+1]));
             j += size;
         }
         
         // Reverse prev block hash every 4 bytes... Makes a lot of sense...
-        ByteBuffer prevhashbuf(Util::Reverse(job.block->prevBlockHash));
+        ByteBuffer prevhashbuf(Util::Reverse(job->block->prevBlockHash));
         std::vector<uint32> prevhash(8);
         prevhashbuf >> prevhash[7] >> prevhash[6] >> prevhash[5] >> prevhash[4] >> prevhash[3] >> prevhash[2] >> prevhash[1] >> prevhash[0];
         ByteBuffer prevhashfixed;
@@ -67,12 +67,12 @@ namespace Stratum
         JSON params;
         params.Add(jobss.str());
         params.Add(Util::BinToASCII(prevhashfixed.Binary()));
-        params.Add(Util::BinToASCII(job.coinbase1));
-        params.Add(Util::BinToASCII(job.coinbase2));
+        params.Add(Util::BinToASCII(job->coinbase1));
+        params.Add(Util::BinToASCII(job->coinbase2));
         params.Add(merkle_branch);
-        params.Add(Util::BinToASCII(Util::Reverse(ByteBuffer(job.block->version).Binary())));
-        params.Add(Util::BinToASCII(Util::Reverse(ByteBuffer(job.block->bits).Binary())));
-        params.Add(Util::BinToASCII(Util::Reverse(ByteBuffer(job.block->time).Binary())));
+        params.Add(Util::BinToASCII(Util::Reverse(ByteBuffer(job->block->version).Binary())));
+        params.Add(Util::BinToASCII(Util::Reverse(ByteBuffer(job->block->bits).Binary())));
+        params.Add(Util::BinToASCII(Util::Reverse(ByteBuffer(job->block->time).Binary())));
         params.Add(clean);
         
         JSON msg;
@@ -122,10 +122,10 @@ namespace Stratum
         }
         
         // Get job
-        Job& job = _jobs[jobid];
+        Job* job = _jobs[jobid];
         
         // Share limiter
-        if (!_shareLimiter.Submit(job.diff)) {
+        if (!_shareLimiter.Submit(job->diff)) {
             JSON response;
             response["id"] = msg["id"];
             response["result"];
@@ -183,9 +183,9 @@ namespace Stratum
         
         sLog.Debug(LOG_STRATUM, "Job::SubmitShare: Nonce: %s, Extranonce: %s, Share: %u", Util::BinToASCII(noncebuf.Binary()).c_str(), Util::BinToASCII(extranonce2).c_str(), share);
         
-        if (!job.SubmitShare(share)) {
+        if (!job->SubmitShare(share)) {
             sLog.Warn(LOG_STRATUM, "%s: Duplicate share", username.c_str());
-            DataMgr::Instance()->Push(Share(_ip, username, false, "Duplicate share", Util::Date(), job.diff));
+            DataMgr::Instance()->Push(Share(_ip, username, false, "Duplicate share", Util::Date(), job->diff));
             _shareLimiter.LogBad();
             
             JSON response;
@@ -199,7 +199,7 @@ namespace Stratum
         }
         
         // Copy block we are working on
-        Bitcoin::Block block = *job.block;
+        Bitcoin::Block block = *job->block;
         
         // Start assembling the block
         timebuf >> block.time;
@@ -208,7 +208,7 @@ namespace Stratum
         // Assemble coinbase
         Bitcoin::Transaction coinbasetx;
         ByteBuffer coinbasebuf;
-        coinbasebuf << job.coinbase1 << _extranonce << extranonce2 << job.coinbase2;
+        coinbasebuf << job->coinbase1 << _extranonce << extranonce2 << job->coinbase2;
         coinbasebuf >> coinbasetx;
         
         // Set coinbase tx
@@ -224,9 +224,9 @@ namespace Stratum
         BigInt target(Util::BinToASCII(Util::Reverse(hash)), 16);
         
         // Check if difficulty meets job diff
-        if (target > job.jobTarget) {
+        if (target > job->jobTarget) {
             sLog.Warn(LOG_STRATUM, "%s: Share above target", username.c_str());
-            DataMgr::Instance()->Push(Share(_ip, username, false, "Share above target", Util::Date(), job.diff));
+            DataMgr::Instance()->Push(Share(_ip, username, false, "Share above target", Util::Date(), job->diff));
             _shareLimiter.LogBad();
             
             JSON response;
@@ -240,11 +240,11 @@ namespace Stratum
         }
         
         // Check if block meets criteria
-        if (target <= job.blockTarget) {
+        if (target <= job->blockTarget) {
             sLog.Info(LOG_STRATUM, "We have found a block candidate!");
             
             // copy job diff because job will be deleted after submiting share by block template update
-            uint64 jobDiff = job.diff;
+            uint64 jobDiff = job->diff;
             
             if (_server->SubmitBlock(block)) {
                 std::string query("INSERT INTO `shares` (`rem_host`, `username`, `our_result`, `upstream_result`, `reason`, `solution`, `time`, `difficulty`) VALUES ");
@@ -259,7 +259,7 @@ namespace Stratum
                 return;
             }
         } else {
-            DataMgr::Instance()->Push(Share(_ip, username, true, "", Util::Date(), job.diff));
+            DataMgr::Instance()->Push(Share(_ip, username, true, "", Util::Date(), job->diff));
             
             JSON response;
             response["id"] = msg["id"];
@@ -330,17 +330,17 @@ namespace Stratum
         }
     }
     
-    Job Client::GetJob()
+    Job* Client::GetJob()
     {
-        Job job;
-        job.block = _server->GetWork();
-        job.diff = _diff;
-        job.jobTarget = Bitcoin::DiffToTarget(job.diff);
-        job.blockTarget = Bitcoin::TargetFromBits(job.block->bits);
+        Job* job = new Job();
+        job->block = _server->GetWork();
+        job->diff = _diff;
+        job->jobTarget = Bitcoin::DiffToTarget(job->diff);
+        job->blockTarget = Bitcoin::TargetFromBits(job->block->bits);
         
         // Serialize transaction
         ByteBuffer coinbasebuf;
-        coinbasebuf << job.block->tx[0];
+        coinbasebuf << job->block->tx[0];
         BinaryData coinbase = coinbasebuf.Binary();
         
         // Split coinbase
@@ -350,8 +350,8 @@ namespace Stratum
         // tx.script (varint)           - 2 bytes
         // tx.script (block height)     - 4 bytes
         uint32 cbsplit = 4 + 32 + 4 + 2 + 4;
-        job.coinbase1 = BinaryData(coinbase.begin(), coinbase.begin() + cbsplit);
-        job.coinbase2 = BinaryData(coinbase.begin() + cbsplit + 8, coinbase.end()); // plus extranonce size
+        job->coinbase1 = BinaryData(coinbase.begin(), coinbase.begin() + cbsplit);
+        job->coinbase2 = BinaryData(coinbase.begin() + cbsplit + 8, coinbase.end()); // plus extranonce size
         
         return job;
     }

src/server/poolserver/Stratum/Client.h

@@ -27,12 +27,13 @@ namespace Stratum
     public:
         Client(Server* server, asio::io_service& io_service, uint64 id) : _io_service(io_service), _server(server), _socket(io_service), _ioStrand(io_service), _id(id), _subscribed(false), _jobid(0), _shareLimiter(this)
         {
-            _diff = sConfig.Get<uint32>("RetargetMinDiff");
+            _diff = sConfig.Get<uint32>("RetargetStartingDiff");
             _minDiff = sConfig.Get<uint32>("RetargetMinDiff");
         }
         
         ~Client()
         {
+            CleanJobs();
             sLog.Info(LOG_STRATUM, "%u: I'm going out! Cya!", _ip);
         }
         
@@ -89,7 +90,14 @@ namespace Stratum
         }
         
         // Gets new job from the server
-        Job GetJob();
+        Job* GetJob();
+        
+        void CleanJobs()
+        {
+            for (std::map<uint64, Job*>::iterator it = _jobs.begin(); it != _jobs.end(); ++it)
+                delete it->second;
+            _jobs.clear();
+        }
         
         // Worker difficulty
         uint64 GetDifficulty()
@@ -177,7 +185,7 @@ namespace Stratum
         // Jobs
         bool _subscribed;
         uint32 _extranonce;
-        std::map<uint64, Job> _jobs;
+        std::map<uint64, Job*> _jobs;
         uint32 _jobid;
         
         // Share limiting

src/server/poolserver/Stratum/Job.h

@@ -6,6 +6,7 @@
 #include "Util.h"
 #include "BigNum.h"
 #include <set>
+#include <boost/thread.hpp>
 
 namespace Stratum
 {
@@ -24,6 +25,8 @@ namespace Stratum
         // Returns false if the same share already exists
         bool SubmitShare(uint64 share)
         {
+            boost::unique_lock<boost::mutex> guard(_mtx);
+            
             std::set<uint64>::iterator it = shares.find(share);
             if (it == shares.end()) {
                 shares.insert(share);
@@ -31,6 +34,9 @@ namespace Stratum
             } else
                 return false;
         }
+        
+    private:
+        boost::mutex _mtx;
     };
 }
 

src/server/poolserver/Stratum/ShareLimiter.cpp

@@ -12,14 +12,16 @@ namespace Stratum
         ++_totalShares;
         
         uint64 curTime = Util::Date();
-        uint64 sinceLast = curTime - _lastRetarget;
+        uint64 timeSinceRetarget = curTime - _lastRetargetTime;
+        uint64 sharesSinceRetarget = _totalShares - _lastRetargetShares;
         
         _shares.push_back(ShareLimiterRecord(diff, curTime));
         
-        if (sinceLast < sConfig.Get<uint32>("RetargetInterval"))
+        if (timeSinceRetarget < sConfig.Get<uint32>("RetargetInterval") && sharesSinceRetarget < sConfig.Get<uint32>("RetargetSharesThreshold"))
             return true;
         
-        _lastRetarget = curTime;
+        _lastRetargetTime = curTime;
+        _lastRetargetShares = _totalShares;
         
         // Check if miner is ok
         if (_totalShares > 200 && (double(_totalBadShares)/double(_totalShares)) > 0.9) {
@@ -61,6 +63,12 @@ namespace Stratum
         if (variance < sConfig.Get<uint32>("RetargetVariance"))
             return true;
         
+        // If variance is huge, reset difficulty with job discard (DoS prevention)
+        if (variance > 2000) {
+            _client->SetDifficulty(newDiff, false);
+            _client->SendJob(true);
+            return false;
+        } else
             _client->SetDifficulty(newDiff, true);
         
         return true;

src/server/poolserver/Stratum/ShareLimiter.h

@@ -25,9 +25,9 @@ namespace Stratum
     public:
         ShareLimiter(Client* client) : _client(client), _totalShares(0), _totalBadShares(0)
         {
-            // Minus one to prevent crash when interval is zero
-            _startTime = Util::Date()-1;
-            _lastRetarget = _startTime;
+            // Minus to prevent crash when interval is zero
+            _startTime = Util::Date()-10;
+            _lastRetargetTime = _startTime;
         }
         
         bool Submit(uint64 diff);
@@ -40,7 +40,8 @@ namespace Stratum
     private:
         std::deque<ShareLimiterRecord> _shares;
         Client* _client;
-        uint64 _lastRetarget;
+        uint64 _lastRetargetTime;
+        uint64 _lastRetargetShares;
         uint64 _startTime;
         
         uint64 _totalShares;