sendmany RPC command, to send to multiple recipients in one transaction.

main.cpp

@@ -678,7 +678,11 @@ bool CTransaction::AcceptToMemoryPool(CTxDB& txdb, bool fCheckInputs, bool* pfMi
 
     // Safety limits
     unsigned int nSize = ::GetSerializeSize(*this, SER_NETWORK);
-    if (GetSigOpCount() > 2 || nSize < 100)
+    // Checking ECDSA signatures is a CPU bottleneck, so to avoid denial-of-service
+    // attacks disallow transactions with more than one SigOp per 34 bytes.
+    // 34 bytes because a TxOut is:
+    //   20-byte address + 8 byte bitcoin amount + 5 bytes of ops + 1 byte script length
+    if (GetSigOpCount() > nSize / 34 || nSize < 100)
         return error("AcceptToMemoryPool() : nonstandard transaction");
 
     // Rather not work on nonstandard transactions
@@ -3846,8 +3850,18 @@ bool SelectCoins(int64 nTargetValue, set<CWalletTx*>& setCoinsRet)
 
 
 
-bool CreateTransaction(CScript scriptPubKey, int64 nValue, CWalletTx& wtxNew, CReserveKey& reservekey, int64& nFeeRet)
+bool CreateTransaction(const vector<pair<CScript, int64> >& vecSend, CWalletTx& wtxNew, CReserveKey& reservekey, int64& nFeeRet)
+{
+    int64 nValue = 0;
+    foreach (const PAIRTYPE(CScript, int64)& s, vecSend)
     {
+        if (nValue < 0)
+            return false;
+        nValue += s.second;
+    }
+    if (vecSend.empty() || nValue < 0)
+        return false;
+
     CRITICAL_BLOCK(cs_main)
     {
         // txdb must be opened before the mapWallet lock
@@ -3860,11 +3874,12 @@ bool CreateTransaction(CScript scriptPubKey, int64 nValue, CWalletTx& wtxNew, CR
                 wtxNew.vin.clear();
                 wtxNew.vout.clear();
                 wtxNew.fFromMe = true;
-                if (nValue < 0)
+
-                    return false;
-                int64 nValueOut = nValue;
                 int64 nTotalValue = nValue + nFeeRet;
                 double dPriority = 0;
+                // vouts to the payees
+                foreach (const PAIRTYPE(CScript, int64)& s, vecSend)
+                    wtxNew.vout.push_back(CTxOut(s.second, s.first));
 
                 // Choose coins to use
                 set<CWalletTx*> setCoins;
@@ -3878,11 +3893,6 @@ bool CreateTransaction(CScript scriptPubKey, int64 nValue, CWalletTx& wtxNew, CR
                     dPriority += (double)nCredit * pcoin->GetDepthInMainChain();
                 }
 
-                // Fill a vout to the payee
-                bool fChangeFirst = GetRand(2);
-                if (!fChangeFirst)
-                    wtxNew.vout.push_back(CTxOut(nValueOut, scriptPubKey));
-
                 // Fill a vout back to self with any change
                 int64 nChange = nValueIn - nTotalValue;
                 if (nChange >= CENT)
@@ -3900,19 +3910,18 @@ bool CreateTransaction(CScript scriptPubKey, int64 nValue, CWalletTx& wtxNew, CR
 
                     // Fill a vout to ourself, using same address type as the payment
                     CScript scriptChange;
-                    if (scriptPubKey.GetBitcoinAddressHash160() != 0)
+                    if (vecSend[0].first.GetBitcoinAddressHash160() != 0)
                         scriptChange.SetBitcoinAddress(vchPubKey);
                     else
                         scriptChange << vchPubKey << OP_CHECKSIG;
-                    wtxNew.vout.push_back(CTxOut(nChange, scriptChange));
+
+                    // Insert change txn at random position:
+                    vector<CTxOut>::iterator position = wtxNew.vout.begin()+GetRandInt(wtxNew.vout.size());
+                    wtxNew.vout.insert(position, CTxOut(nChange, scriptChange));
                 }
                 else
                     reservekey.ReturnKey();
 
-                // Fill a vout to the payee
-                if (fChangeFirst)
-                    wtxNew.vout.push_back(CTxOut(nValueOut, scriptPubKey));
-
                 // Fill vin
                 foreach(CWalletTx* pcoin, setCoins)
                     for (int nOut = 0; nOut < pcoin->vout.size(); nOut++)
@@ -3954,6 +3963,13 @@ bool CreateTransaction(CScript scriptPubKey, int64 nValue, CWalletTx& wtxNew, CR
     return true;
 }
 
+bool CreateTransaction(CScript scriptPubKey, int64 nValue, CWalletTx& wtxNew, CReserveKey& reservekey, int64& nFeeRet)
+{
+    vector< pair<CScript, int64> > vecSend;
+    vecSend.push_back(make_pair(scriptPubKey, nValue));
+    return CreateTransaction(vecSend, wtxNew, reservekey, nFeeRet);
+}
+
 // Call after CreateTransaction unless you want to abort
 bool CommitTransaction(CWalletTx& wtxNew, CReserveKey& reservekey)
 {

main.h

@@ -77,6 +77,7 @@ bool ProcessMessages(CNode* pfrom);
 bool ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv);
 bool SendMessages(CNode* pto, bool fSendTrickle);
 int64 GetBalance();
+bool CreateTransaction(const vector<pair<CScript, int64> >& vecSend, CWalletTx& wtxNew, CReserveKey& reservekey, int64& nFeeRet);
 bool CreateTransaction(CScript scriptPubKey, int64 nValue, CWalletTx& wtxNew, CReserveKey& reservekey, int64& nFeeRet);
 bool CommitTransaction(CWalletTx& wtxNew, CReserveKey& reservekey);
 bool BroadcastTransaction(CWalletTx& wtxNew);

rpc.cpp

@@ -768,6 +768,69 @@ Value sendfrom(const Array& params, bool fHelp)
     return wtx.GetHash().GetHex();
 }
 
+Value sendmany(const Array& params, bool fHelp)
+{
+    if (fHelp || params.size() < 2 || params.size() > 4)
+        throw runtime_error(
+            "sendmany <fromaccount> {address:amount,...} [minconf=1] [comment]\n"
+            "amounts are double-precision floating point numbers");
+
+    string strAccount = AccountFromValue(params[0]);
+    Object sendTo = params[1].get_obj();
+    int nMinDepth = 1;
+    if (params.size() > 2)
+        nMinDepth = params[2].get_int();
+
+    CWalletTx wtx;
+    wtx.strFromAccount = strAccount;
+    if (params.size() > 3 && params[3].type() != null_type && !params[3].get_str().empty())
+        wtx.mapValue["comment"] = params[3].get_str();
+
+    set<string> setAddress;
+    vector<pair<CScript, int64> > vecSend;
+
+    int64 totalAmount = 0;
+    foreach(const Pair& s, sendTo)
+    {
+        uint160 hash160;
+        string strAddress = s.name_;
+
+        if (setAddress.count(strAddress))
+            throw JSONRPCError(-8, string("Invalid parameter, duplicated address: ")+strAddress);
+        setAddress.insert(strAddress);
+
+        CScript scriptPubKey;
+        if (!scriptPubKey.SetBitcoinAddress(strAddress))
+            throw JSONRPCError(-5, string("Invalid bitcoin address:")+strAddress);
+        int64 nAmount = AmountFromValue(s.value_); 
+        totalAmount += nAmount;
+
+        vecSend.push_back(make_pair(scriptPubKey, nAmount));
+    }
+
+    CRITICAL_BLOCK(cs_mapWallet)
+    {
+        // Check funds
+        int64 nBalance = GetAccountBalance(strAccount, nMinDepth);
+        if (totalAmount > nBalance)
+            throw JSONRPCError(-6, "Account has insufficient funds");
+
+        // Send
+        CReserveKey keyChange;
+        int64 nFeeRequired = 0;
+        bool fCreated = CreateTransaction(vecSend, wtx, keyChange, nFeeRequired);
+        if (!fCreated)
+        {
+            if (totalAmount + nFeeRequired > GetBalance())
+                throw JSONRPCError(-6, "Insufficient funds");
+            throw JSONRPCError(-4, "Transaction creation failed");
+        }
+        if (!CommitTransaction(wtx, keyChange))
+            throw JSONRPCError(-4, "Transaction commit failed");
+    }
+
+    return wtx.GetHash().GetHex();
+}
 
 
 struct tallyitem
@@ -1344,6 +1407,7 @@ pair<string, rpcfn_type> pCallTable[] =
     make_pair("getbalance",            &getbalance),
     make_pair("move",                  &movecmd),
     make_pair("sendfrom",              &sendfrom),
+    make_pair("sendmany",              &sendmany),
     make_pair("gettransaction",        &gettransaction),
     make_pair("listtransactions",      &listtransactions),
     make_pair("getwork",               &getwork),
@@ -1995,6 +2059,15 @@ int CommandLineRPC(int argc, char *argv[])
         if (strMethod == "sendfrom"               && n > 3) ConvertTo<boost::int64_t>(params[3]);
         if (strMethod == "listtransactions"       && n > 1) ConvertTo<boost::int64_t>(params[1]);
         if (strMethod == "listaccounts"           && n > 0) ConvertTo<boost::int64_t>(params[0]);
+        if (strMethod == "sendmany"               && n > 1)
+        {
+            string s = params[1].get_str();
+            Value v;
+            if (!read_string(s, v) || v.type() != obj_type)
+                throw runtime_error("type mismatch");
+            params[1] = v.get_obj();
+        }
+        if (strMethod == "sendmany"                && n > 2) ConvertTo<boost::int64_t>(params[2]);
 
         // Execute
         Object reply = CallRPC(strMethod, params);