Litecoin: Add mininput to deal with dust spam. By default, mininput is set to 0.0001. This means that create transaction will ignore any transactions with an output value less than 0.0001. You can override the default by passing in -mininput on startup or by calling setmininput.

Historically this patch allowed wallets to perform without delay after the dust spam attack during November 2011.

src/bitcoinrpc.cpp

@@ -249,6 +249,7 @@ static const CRPCCommand vRPCCommands[] =
     { "settxfee",               &settxfee,               false,     false },
     { "getblocktemplate",       &getblocktemplate,       true,      false },
     { "submitblock",            &submitblock,            false,     false },
+    { "setmininput",            &setmininput,            false,     false },
     { "listsinceblock",         &listsinceblock,         false,     false },
     { "dumpprivkey",            &dumpprivkey,            true,      false },
     { "importprivkey",          &importprivkey,          false,     false },
@@ -1149,6 +1150,7 @@ Array RPCConvertValues(const std::string &strMethod, const std::vector<std::stri
     if (strMethod == "getnetworkhashps"       && n > 0) ConvertTo<boost::int64_t>(params[0]);
     if (strMethod == "sendtoaddress"          && n > 1) ConvertTo<double>(params[1]);
     if (strMethod == "settxfee"               && n > 0) ConvertTo<double>(params[0]);
+    if (strMethod == "setmininput"            && n > 0) ConvertTo<double>(params[0]);
     if (strMethod == "getreceivedbyaddress"   && n > 1) ConvertTo<boost::int64_t>(params[1]);
     if (strMethod == "getreceivedbyaccount"   && n > 1) ConvertTo<boost::int64_t>(params[1]);
     if (strMethod == "listreceivedbyaddress"  && n > 0) ConvertTo<boost::int64_t>(params[0]);

src/bitcoinrpc.h

@@ -193,6 +193,7 @@ extern json_spirit::Value sendrawtransaction(const json_spirit::Array& params, b
 extern json_spirit::Value getblockcount(const json_spirit::Array& params, bool fHelp); // in rpcblockchain.cpp
 extern json_spirit::Value getdifficulty(const json_spirit::Array& params, bool fHelp);
 extern json_spirit::Value settxfee(const json_spirit::Array& params, bool fHelp);
+extern json_spirit::Value setmininput(const json_spirit::Array& params, bool fHelp);
 extern json_spirit::Value getrawmempool(const json_spirit::Array& params, bool fHelp);
 extern json_spirit::Value getblockhash(const json_spirit::Array& params, bool fHelp);
 extern json_spirit::Value getblock(const json_spirit::Array& params, bool fHelp);

src/init.cpp

@@ -324,6 +324,7 @@ std::string HelpMessage()
 #endif
 #endif
         "  -paytxfee=<amt>        " + _("Fee per KB to add to transactions you send") + "\n" +
+        "  -mininput=<amt>        " + _("When creating transactions, ignore inputs with value less than this (default: 0.0001)") + "\n" +
 #ifdef QT_GUI
         "  -server                " + _("Accept command line and JSON-RPC commands") + "\n" +
 #endif
@@ -615,6 +616,12 @@ bool AppInit2(boost::thread_group& threadGroup)
             InitWarning(_("Warning: -paytxfee is set very high! This is the transaction fee you will pay if you send a transaction."));
     }
 
+    if (mapArgs.count("-mininput"))
+    {
+        if (!ParseMoney(mapArgs["-mininput"], nMinimumInputValue))
+            return InitError(strprintf(_("Invalid amount for -mininput=<amount>: '%s'"), mapArgs["-mininput"].c_str()));
+    }
+
     // ********************************************************* Step 4: application initialization: dir lock, daemonize, pidfile, debug log
 
     std::string strDataDir = GetDataDir().string();

src/main.cpp

@@ -71,7 +71,7 @@ int64 nHPSTimerStart = 0;
 
 // Settings
 int64 nTransactionFee = 0;
-
+int64 nMinimumInputValue = CENT / 100;
 
 
 //////////////////////////////////////////////////////////////////////////////

src/main.h

@@ -97,6 +97,7 @@ extern unsigned int nCoinCacheSize;
 
 // Settings
 extern int64 nTransactionFee;
+extern int64 nMinimumInputValue;
 
 // Minimum disk space required - used in CheckDiskSpace()
 static const uint64 nMinDiskSpace = 52428800;

src/rpcwallet.cpp

@@ -83,6 +83,7 @@ Value getinfo(const Array& params, bool fHelp)
     obj.push_back(Pair("keypoololdest", (boost::int64_t)pwalletMain->GetOldestKeyPoolTime()));
     obj.push_back(Pair("keypoolsize",   pwalletMain->GetKeyPoolSize()));
     obj.push_back(Pair("paytxfee",      ValueFromAmount(nTransactionFee)));
+    obj.push_back(Pair("mininput",      ValueFromAmount(nMinimumInputValue)));
     if (pwalletMain->IsCrypted())
         obj.push_back(Pair("unlocked_until", (boost::int64_t)nWalletUnlockTime / 1000));
     obj.push_back(Pair("errors",        GetWarnings("statusbar")));
@@ -247,6 +248,24 @@ Value getaddressesbyaccount(const Array& params, bool fHelp)
     return ret;
 }
 
+
+Value setmininput(const Array& params, bool fHelp)
+{
+    if (fHelp || params.size() < 1 || params.size() > 1)
+        throw runtime_error(
+            "setmininput <amount>\n"
+            "<amount> is a real and is rounded to the nearest 0.00000001");
+
+    // Amount
+    int64 nAmount = 0;
+    if (params[0].get_real() != 0.0)
+        nAmount = AmountFromValue(params[0]);        // rejects 0.0 amounts
+
+    nMinimumInputValue = nAmount;
+    return true;
+}
+
+
 Value sendtoaddress(const Array& params, bool fHelp)
 {
     if (fHelp || params.size() < 2 || params.size() > 4)

src/wallet.cpp

@@ -976,7 +976,7 @@ void CWallet::AvailableCoins(vector<COutput>& vCoins, bool fOnlyConfirmed) const
 
             for (unsigned int i = 0; i < pcoin->vout.size(); i++) {
                 if (!(pcoin->IsSpent(i)) && IsMine(pcoin->vout[i]) &&
-                    !IsLockedCoin((*it).first, i) && pcoin->vout[i].nValue > 0)
+                    !IsLockedCoin((*it).first, i) && pcoin->vout[i].nValue >= nMinimumInputValue)
                     vCoins.push_back(COutput(pcoin, i, pcoin->GetDepthInMainChain()));
             }
         }

src/wallet.h

@@ -221,7 +221,7 @@ public:
     bool IsMine(const CTransaction& tx) const
     {
         BOOST_FOREACH(const CTxOut& txout, tx.vout)
-            if (IsMine(txout))
+            if (IsMine(txout) && txout.nValue >= nMinimumInputValue)
                 return true;
         return false;
     }