20 files changed, 439 insertions, 290 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 5a5e3abcfa..69ae02f582 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -111,6 +111,7 @@ BITCOIN_CORE_H = \
   net.h \
   netaddress.h \
   netbase.h \
+  netmessagemaker.h \
   noui.h \
   policy/fees.h \
   policy/policy.h \
diff --git a/src/bitcoin-cli.cpp b/src/bitcoin-cli.cpp
index 392d1b9329..b272640819 100644
--- a/src/bitcoin-cli.cpp
+++ b/src/bitcoin-cli.cpp
@@ -24,15 +24,13 @@
 
 #include <univalue.h>
 
-using namespace std;
-
 static const char DEFAULT_RPCCONNECT[] = "127.0.0.1";
 static const int DEFAULT_HTTP_CLIENT_TIMEOUT=900;
 static const int CONTINUE_EXECUTION=-1;
 
 std::string HelpMessageCli()
 {
-    string strUsage;
+    std::string strUsage;
     strUsage += HelpMessageGroup(_("Options:"));
     strUsage += HelpMessageOpt("-?", _("This help message"));
     strUsage += HelpMessageOpt("-conf=<file>", strprintf(_("Specify configuration file (default: %s)"), BITCOIN_CONF_FILENAME));
@@ -187,7 +185,7 @@ static void http_error_cb(enum evhttp_request_error err, void *ctx)
 }
 #endif
 
-UniValue CallRPC(const string& strMethod, const UniValue& params)
+UniValue CallRPC(const std::string& strMethod, const UniValue& params)
 {
     std::string host = GetArg("-rpcconnect", DEFAULT_RPCCONNECT);
     int port = GetArg("-rpcport", BaseParams().RPCPort());
@@ -195,18 +193,18 @@ UniValue CallRPC(const string& strMethod, const UniValue& params)
     // Create event base
     struct event_base *base = event_base_new(); // TODO RAII
     if (!base)
-        throw runtime_error("cannot create event_base");
+        throw std::runtime_error("cannot create event_base");
 
     // Synchronously look up hostname
     struct evhttp_connection *evcon = evhttp_connection_base_new(base, NULL, host.c_str(), port); // TODO RAII
     if (evcon == NULL)
-        throw runtime_error("create connection failed");
+        throw std::runtime_error("create connection failed");
     evhttp_connection_set_timeout(evcon, GetArg("-rpcclienttimeout", DEFAULT_HTTP_CLIENT_TIMEOUT));
 
     HTTPReply response;
     struct evhttp_request *req = evhttp_request_new(http_request_done, (void*)&response); // TODO RAII
     if (req == NULL)
-        throw runtime_error("create http request failed");
+        throw std::runtime_error("create http request failed");
 #if LIBEVENT_VERSION_NUMBER >= 0x02010300
     evhttp_request_set_error_cb(req, http_error_cb);
 #endif
@@ -216,7 +214,7 @@ UniValue CallRPC(const string& strMethod, const UniValue& params)
     if (mapArgs["-rpcpassword"] == "") {
         // Try fall back to cookie-based authentication if no password is provided
         if (!GetAuthCookie(&strRPCUserColonPass)) {
-            throw runtime_error(strprintf(
+            throw std::runtime_error(strprintf(
                 _("Could not locate RPC credentials. No authentication cookie could be found, and no rpcpassword is set in the configuration file (%s)"),
                     GetConfigFile(GetArg("-conf", BITCOIN_CONF_FILENAME)).string().c_str()));
 
@@ -251,26 +249,26 @@ UniValue CallRPC(const string& strMethod, const UniValue& params)
     if (response.status == 0)
         throw CConnectionFailed(strprintf("couldn't connect to server\n(make sure server is running and you are connecting to the correct RPC port: %d %s)", response.error, http_errorstring(response.error)));
     else if (response.status == HTTP_UNAUTHORIZED)
-        throw runtime_error("incorrect rpcuser or rpcpassword (authorization failed)");
+        throw std::runtime_error("incorrect rpcuser or rpcpassword (authorization failed)");
     else if (response.status >= 400 && response.status != HTTP_BAD_REQUEST && response.status != HTTP_NOT_FOUND && response.status != HTTP_INTERNAL_SERVER_ERROR)
-        throw runtime_error(strprintf("server returned HTTP error %d", response.status));
+        throw std::runtime_error(strprintf("server returned HTTP error %d", response.status));
     else if (response.body.empty())
-        throw runtime_error("no response from server");
+        throw std::runtime_error("no response from server");
 
     // Parse reply
     UniValue valReply(UniValue::VSTR);
     if (!valReply.read(response.body))
-        throw runtime_error("couldn't parse reply from server");
+        throw std::runtime_error("couldn't parse reply from server");
     const UniValue& reply = valReply.get_obj();
     if (reply.empty())
-        throw runtime_error("expected reply to have result, error and id properties");
+        throw std::runtime_error("expected reply to have result, error and id properties");
 
     return reply;
 }
 
 int CommandLineRPC(int argc, char *argv[])
 {
-    string strPrint;
+    std::string strPrint;
     int nRet = 0;
     try {
         // Skip switches
@@ -286,7 +284,7 @@ int CommandLineRPC(int argc, char *argv[])
                 args.push_back(line);
         }
         if (args.size() < 1)
-            throw runtime_error("too few parameters (need at least command)");
+            throw std::runtime_error("too few parameters (need at least command)");
         std::string strMethod = args[0];
         UniValue params = RPCConvertValues(strMethod, std::vector<std::string>(args.begin()+1, args.end()));
 
@@ -340,7 +338,7 @@ int CommandLineRPC(int argc, char *argv[])
         throw;
     }
     catch (const std::exception& e) {
-        strPrint = string("error: ") + e.what();
+        strPrint = std::string("error: ") + e.what();
         nRet = EXIT_FAILURE;
     }
     catch (...) {
diff --git a/src/bitcoin-tx.cpp b/src/bitcoin-tx.cpp
index 6d17bc392f..346d8e180d 100644
--- a/src/bitcoin-tx.cpp
+++ b/src/bitcoin-tx.cpp
@@ -26,10 +26,8 @@
 #include <boost/algorithm/string.hpp>
 #include <boost/assign/list_of.hpp>
 
-using namespace std;
-
 static bool fCreateBlank;
-static map<string,UniValue> registers;
+static std::map<std::string,UniValue> registers;
 static const int CONTINUE_EXECUTION=-1;
 
 //
@@ -103,52 +101,52 @@ static int AppInitRawTx(int argc, char* argv[])
     return CONTINUE_EXECUTION;
 }
 
-static void RegisterSetJson(const string& key, const string& rawJson)
+static void RegisterSetJson(const std::string& key, const std::string& rawJson)
 {
     UniValue val;
     if (!val.read(rawJson)) {
-        string strErr = "Cannot parse JSON for key " + key;
-        throw runtime_error(strErr);
+        std::string strErr = "Cannot parse JSON for key " + key;
+        throw std::runtime_error(strErr);
     }
 
     registers[key] = val;
 }
 
-static void RegisterSet(const string& strInput)
+static void RegisterSet(const std::string& strInput)
 {
     // separate NAME:VALUE in string
     size_t pos = strInput.find(':');
-    if ((pos == string::npos) ||
+    if ((pos == std::string::npos) ||
         (pos == 0) ||
         (pos == (strInput.size() - 1)))
-        throw runtime_error("Register input requires NAME:VALUE");
+        throw std::runtime_error("Register input requires NAME:VALUE");
 
-    string key = strInput.substr(0, pos);
-    string valStr = strInput.substr(pos + 1, string::npos);
+    std::string key = strInput.substr(0, pos);
+    std::string valStr = strInput.substr(pos + 1, std::string::npos);
 
     RegisterSetJson(key, valStr);
 }
 
-static void RegisterLoad(const string& strInput)
+static void RegisterLoad(const std::string& strInput)
 {
     // separate NAME:FILENAME in string
     size_t pos = strInput.find(':');
-    if ((pos == string::npos) ||
+    if ((pos == std::string::npos) ||
         (pos == 0) ||
         (pos == (strInput.size() - 1)))
-        throw runtime_error("Register load requires NAME:FILENAME");
+        throw std::runtime_error("Register load requires NAME:FILENAME");
 
-    string key = strInput.substr(0, pos);
-    string filename = strInput.substr(pos + 1, string::npos);
+    std::string key = strInput.substr(0, pos);
+    std::string filename = strInput.substr(pos + 1, std::string::npos);
 
     FILE *f = fopen(filename.c_str(), "r");
     if (!f) {
-        string strErr = "Cannot open file " + filename;
-        throw runtime_error(strErr);
+        std::string strErr = "Cannot open file " + filename;
+        throw std::runtime_error(strErr);
     }
 
     // load file chunks into one big buffer
-    string valStr;
+    std::string valStr;
     while ((!feof(f)) && (!ferror(f))) {
         char buf[4096];
         int bread = fread(buf, 1, sizeof(buf), f);
@@ -162,55 +160,55 @@ static void RegisterLoad(const string& strInput)
     fclose(f);
 
     if (error) {
-        string strErr = "Error reading file " + filename;
-        throw runtime_error(strErr);
+        std::string strErr = "Error reading file " + filename;
+        throw std::runtime_error(strErr);
     }
 
     // evaluate as JSON buffer register
     RegisterSetJson(key, valStr);
 }
 
-static void MutateTxVersion(CMutableTransaction& tx, const string& cmdVal)
+static void MutateTxVersion(CMutableTransaction& tx, const std::string& cmdVal)
 {
     int64_t newVersion = atoi64(cmdVal);
     if (newVersion < 1 || newVersion > CTransaction::MAX_STANDARD_VERSION)
-        throw runtime_error("Invalid TX version requested");
+        throw std::runtime_error("Invalid TX version requested");
 
     tx.nVersion = (int) newVersion;
 }
 
-static void MutateTxLocktime(CMutableTransaction& tx, const string& cmdVal)
+static void MutateTxLocktime(CMutableTransaction& tx, const std::string& cmdVal)
 {
     int64_t newLocktime = atoi64(cmdVal);
     if (newLocktime < 0LL || newLocktime > 0xffffffffLL)
-        throw runtime_error("Invalid TX locktime requested");
+        throw std::runtime_error("Invalid TX locktime requested");
 
     tx.nLockTime = (unsigned int) newLocktime;
 }
 
-static void MutateTxAddInput(CMutableTransaction& tx, const string& strInput)
+static void MutateTxAddInput(CMutableTransaction& tx, const std::string& strInput)
 {
     std::vector<std::string> vStrInputParts;
     boost::split(vStrInputParts, strInput, boost::is_any_of(":"));
 
     // separate TXID:VOUT in string
     if (vStrInputParts.size()<2)
-        throw runtime_error("TX input missing separator");
+        throw std::runtime_error("TX input missing separator");
 
     // extract and validate TXID
-    string strTxid = vStrInputParts[0];
+    std::string strTxid = vStrInputParts[0];
     if ((strTxid.size() != 64) || !IsHex(strTxid))
-        throw runtime_error("invalid TX input txid");
+        throw std::runtime_error("invalid TX input txid");
     uint256 txid(uint256S(strTxid));
 
     static const unsigned int minTxOutSz = 9;
     static const unsigned int maxVout = MAX_BLOCK_BASE_SIZE / minTxOutSz;
 
     // extract and validate vout
-    string strVout = vStrInputParts[1];
+    std::string strVout = vStrInputParts[1];
     int vout = atoi(strVout);
     if ((vout < 0) || (vout > (int)maxVout))
-        throw runtime_error("invalid TX input vout");
+        throw std::runtime_error("invalid TX input vout");
 
     // extract the optional sequence number
     uint32_t nSequenceIn=std::numeric_limits<unsigned int>::max();
@@ -222,26 +220,26 @@ static void MutateTxAddInput(CMutableTransaction& tx, const string& strInput)
     tx.vin.push_back(txin);
 }
 
-static void MutateTxAddOutAddr(CMutableTransaction& tx, const string& strInput)
+static void MutateTxAddOutAddr(CMutableTransaction& tx, const std::string& strInput)
 {
     // separate VALUE:ADDRESS in string
     size_t pos = strInput.find(':');
-    if ((pos == string::npos) ||
+    if ((pos == std::string::npos) ||
         (pos == 0) ||
         (pos == (strInput.size() - 1)))
-        throw runtime_error("TX output missing separator");
+        throw std::runtime_error("TX output missing separator");
 
     // extract and validate VALUE
-    string strValue = strInput.substr(0, pos);
+    std::string strValue = strInput.substr(0, pos);
     CAmount value;
     if (!ParseMoney(strValue, value))
-        throw runtime_error("invalid TX output value");
+        throw std::runtime_error("invalid TX output value");
 
     // extract and validate ADDRESS
-    string strAddr = strInput.substr(pos + 1, string::npos);
+    std::string strAddr = strInput.substr(pos + 1, std::string::npos);
     CBitcoinAddress addr(strAddr);
     if (!addr.IsValid())
-        throw runtime_error("invalid TX output address");
+        throw std::runtime_error("invalid TX output address");
 
     // build standard output script via GetScriptForDestination()
     CScript scriptPubKey = GetScriptForDestination(addr.Get());
@@ -251,7 +249,7 @@ static void MutateTxAddOutAddr(CMutableTransaction& tx, const string& strInput)
     tx.vout.push_back(txout);
 }
 
-static void MutateTxAddOutData(CMutableTransaction& tx, const string& strInput)
+static void MutateTxAddOutData(CMutableTransaction& tx, const std::string& strInput)
 {
     CAmount value = 0;
 
@@ -259,20 +257,20 @@ static void MutateTxAddOutData(CMutableTransaction& tx, const string& strInput)
     size_t pos = strInput.find(':');
 
     if (pos==0)
-        throw runtime_error("TX output value not specified");
+        throw std::runtime_error("TX output value not specified");
 
-    if (pos != string::npos) {
+    if (pos != std::string::npos) {
         // extract and validate VALUE
-        string strValue = strInput.substr(0, pos);
+        std::string strValue = strInput.substr(0, pos);
         if (!ParseMoney(strValue, value))
-            throw runtime_error("invalid TX output value");
+            throw std::runtime_error("invalid TX output value");
     }
 
     // extract and validate DATA
-    string strData = strInput.substr(pos + 1, string::npos);
+    std::string strData = strInput.substr(pos + 1, std::string::npos);
 
     if (!IsHex(strData))
-        throw runtime_error("invalid TX output data");
+        throw std::runtime_error("invalid TX output data");
 
     std::vector<unsigned char> data = ParseHex(strData);
 
@@ -280,22 +278,22 @@ static void MutateTxAddOutData(CMutableTransaction& tx, const string& strInput)
     tx.vout.push_back(txout);
 }
 
-static void MutateTxAddOutScript(CMutableTransaction& tx, const string& strInput)
+static void MutateTxAddOutScript(CMutableTransaction& tx, const std::string& strInput)
 {
     // separate VALUE:SCRIPT in string
     size_t pos = strInput.find(':');
-    if ((pos == string::npos) ||
+    if ((pos == std::string::npos) ||
         (pos == 0))
-        throw runtime_error("TX output missing separator");
+        throw std::runtime_error("TX output missing separator");
 
     // extract and validate VALUE
-    string strValue = strInput.substr(0, pos);
+    std::string strValue = strInput.substr(0, pos);
     CAmount value;
     if (!ParseMoney(strValue, value))
-        throw runtime_error("invalid TX output value");
+        throw std::runtime_error("invalid TX output value");
 
     // extract and validate script
-    string strScript = strInput.substr(pos + 1, string::npos);
+    std::string strScript = strInput.substr(pos + 1, std::string::npos);
     CScript scriptPubKey = ParseScript(strScript); // throws on err
 
     // construct TxOut, append to transaction output list
@@ -303,26 +301,26 @@ static void MutateTxAddOutScript(CMutableTransaction& tx, const string& strInput
     tx.vout.push_back(txout);
 }
 
-static void MutateTxDelInput(CMutableTransaction& tx, const string& strInIdx)
+static void MutateTxDelInput(CMutableTransaction& tx, const std::string& strInIdx)
 {
     // parse requested deletion index
     int inIdx = atoi(strInIdx);
     if (inIdx < 0 || inIdx >= (int)tx.vin.size()) {
-        string strErr = "Invalid TX input index '" + strInIdx + "'";
-        throw runtime_error(strErr.c_str());
+        std::string strErr = "Invalid TX input index '" + strInIdx + "'";
+        throw std::runtime_error(strErr.c_str());
     }
 
     // delete input from transaction
     tx.vin.erase(tx.vin.begin() + inIdx);
 }
 
-static void MutateTxDelOutput(CMutableTransaction& tx, const string& strOutIdx)
+static void MutateTxDelOutput(CMutableTransaction& tx, const std::string& strOutIdx)
 {
     // parse requested deletion index
     int outIdx = atoi(strOutIdx);
     if (outIdx < 0 || outIdx >= (int)tx.vout.size()) {
-        string strErr = "Invalid TX output index '" + strOutIdx + "'";
-        throw runtime_error(strErr.c_str());
+        std::string strErr = "Invalid TX output index '" + strOutIdx + "'";
+        throw std::runtime_error(strErr.c_str());
     }
 
     // delete output from transaction
@@ -342,7 +340,7 @@ static const struct {
     {"SINGLE|ANYONECANPAY", SIGHASH_SINGLE|SIGHASH_ANYONECANPAY},
 };
 
-static bool findSighashFlags(int& flags, const string& flagStr)
+static bool findSighashFlags(int& flags, const std::string& flagStr)
 {
     flags = 0;
 
@@ -356,17 +354,17 @@ static bool findSighashFlags(int& flags, const string& flagStr)
     return false;
 }
 
-uint256 ParseHashUO(map<string,UniValue>& o, string strKey)
+uint256 ParseHashUO(std::map<std::string,UniValue>& o, std::string strKey)
 {
     if (!o.count(strKey))
         return uint256();
     return ParseHashUV(o[strKey], strKey);
 }
 
-vector<unsigned char> ParseHexUO(map<string,UniValue>& o, string strKey)
+std::vector<unsigned char> ParseHexUO(std::map<std::string,UniValue>& o, std::string strKey)
 {
     if (!o.count(strKey)) {
-        vector<unsigned char> emptyVec;
+        std::vector<unsigned char> emptyVec;
         return emptyVec;
     }
     return ParseHexUV(o[strKey], strKey);
@@ -375,24 +373,24 @@ vector<unsigned char> ParseHexUO(map<string,UniValue>& o, string strKey)
 static CAmount AmountFromValue(const UniValue& value)
 {
     if (!value.isNum() && !value.isStr())
-        throw runtime_error("Amount is not a number or string");
+        throw std::runtime_error("Amount is not a number or string");
     CAmount amount;
     if (!ParseFixedPoint(value.getValStr(), 8, &amount))
-        throw runtime_error("Invalid amount");
+        throw std::runtime_error("Invalid amount");
     if (!MoneyRange(amount))
-        throw runtime_error("Amount out of range");
+        throw std::runtime_error("Amount out of range");
     return amount;
 }
 
-static void MutateTxSign(CMutableTransaction& tx, const string& flagStr)
+static void MutateTxSign(CMutableTransaction& tx, const std::string& flagStr)
 {
     int nHashType = SIGHASH_ALL;
 
     if (flagStr.size() > 0)
         if (!findSighashFlags(nHashType, flagStr))
-            throw runtime_error("unknown sighash flag/sign option");
+            throw std::runtime_error("unknown sighash flag/sign option");
 
-    vector<CTransaction> txVariants;
+    std::vector<CTransaction> txVariants;
     txVariants.push_back(tx);
 
     // mergedTx will end up with all the signatures; it
@@ -403,17 +401,17 @@ static void MutateTxSign(CMutableTransaction& tx, const string& flagStr)
     CCoinsViewCache view(&viewDummy);
 
     if (!registers.count("privatekeys"))
-        throw runtime_error("privatekeys register variable must be set.");
+        throw std::runtime_error("privatekeys register variable must be set.");
     CBasicKeyStore tempKeystore;
     UniValue keysObj = registers["privatekeys"];
 
     for (unsigned int kidx = 0; kidx < keysObj.size(); kidx++) {
         if (!keysObj[kidx].isStr())
-            throw runtime_error("privatekey not a string");
+            throw std::runtime_error("privatekey not a std::string");
         CBitcoinSecret vchSecret;
         bool fGood = vchSecret.SetString(keysObj[kidx].getValStr());
         if (!fGood)
-            throw runtime_error("privatekey not valid");
+            throw std::runtime_error("privatekey not valid");
 
         CKey key = vchSecret.GetKey();
         tempKeystore.AddKey(key);
@@ -421,34 +419,34 @@ static void MutateTxSign(CMutableTransaction& tx, const string& flagStr)
 
     // Add previous txouts given in the RPC call:
     if (!registers.count("prevtxs"))
-        throw runtime_error("prevtxs register variable must be set.");
+        throw std::runtime_error("prevtxs register variable must be set.");
     UniValue prevtxsObj = registers["prevtxs"];
     {
         for (unsigned int previdx = 0; previdx < prevtxsObj.size(); previdx++) {
             UniValue prevOut = prevtxsObj[previdx];
             if (!prevOut.isObject())
-                throw runtime_error("expected prevtxs internal object");
+                throw std::runtime_error("expected prevtxs internal object");
 
-            map<string,UniValue::VType> types = boost::assign::map_list_of("txid", UniValue::VSTR)("vout",UniValue::VNUM)("scriptPubKey",UniValue::VSTR);
+            std::map<std::string,UniValue::VType> types = boost::assign::map_list_of("txid", UniValue::VSTR)("vout",UniValue::VNUM)("scriptPubKey",UniValue::VSTR);
             if (!prevOut.checkObject(types))
-                throw runtime_error("prevtxs internal object typecheck fail");
+                throw std::runtime_error("prevtxs internal object typecheck fail");
 
             uint256 txid = ParseHashUV(prevOut["txid"], "txid");
 
             int nOut = atoi(prevOut["vout"].getValStr());
             if (nOut < 0)
-                throw runtime_error("vout must be positive");
+                throw std::runtime_error("vout must be positive");
 
-            vector<unsigned char> pkData(ParseHexUV(prevOut["scriptPubKey"], "scriptPubKey"));
+            std::vector<unsigned char> pkData(ParseHexUV(prevOut["scriptPubKey"], "scriptPubKey"));
             CScript scriptPubKey(pkData.begin(), pkData.end());
 
             {
                 CCoinsModifier coins = view.ModifyCoins(txid);
                 if (coins->IsAvailable(nOut) && coins->vout[nOut].scriptPubKey != scriptPubKey) {
-                    string err("Previous output scriptPubKey mismatch:\n");
+                    std::string err("Previous output scriptPubKey mismatch:\n");
                     err = err + ScriptToAsmStr(coins->vout[nOut].scriptPubKey) + "\nvs:\n"+
                         ScriptToAsmStr(scriptPubKey);
-                    throw runtime_error(err);
+                    throw std::runtime_error(err);
                 }
                 if ((unsigned int)nOut >= coins->vout.size())
                     coins->vout.resize(nOut+1);
@@ -464,7 +462,7 @@ static void MutateTxSign(CMutableTransaction& tx, const string& flagStr)
             if ((scriptPubKey.IsPayToScriptHash() || scriptPubKey.IsPayToWitnessScriptHash()) &&
                 prevOut.exists("redeemScript")) {
                 UniValue v = prevOut["redeemScript"];
-                vector<unsigned char> rsData(ParseHexUV(v, "redeemScript"));
+                std::vector<unsigned char> rsData(ParseHexUV(v, "redeemScript"));
                 CScript redeemScript(rsData.begin(), rsData.end());
                 tempKeystore.AddCScript(redeemScript);
             }
@@ -521,8 +519,8 @@ public:
     }
 };
 
-static void MutateTx(CMutableTransaction& tx, const string& command,
-                     const string& commandVal)
+static void MutateTx(CMutableTransaction& tx, const std::string& command,
+                     const std::string& commandVal)
 {
     std::unique_ptr<Secp256k1Init> ecc;
 
@@ -557,7 +555,7 @@ static void MutateTx(CMutableTransaction& tx, const string& command,
         RegisterSet(commandVal);
 
     else
-        throw runtime_error("unknown command");
+        throw std::runtime_error("unknown command");
 }
 
 static void OutputTxJSON(const CTransaction& tx)
@@ -565,20 +563,20 @@ static void OutputTxJSON(const CTransaction& tx)
     UniValue entry(UniValue::VOBJ);
     TxToUniv(tx, uint256(), entry);
 
-    string jsonOutput = entry.write(4);
+    std::string jsonOutput = entry.write(4);
     fprintf(stdout, "%s\n", jsonOutput.c_str());
 }
 
 static void OutputTxHash(const CTransaction& tx)
 {
-    string strHexHash = tx.GetHash().GetHex(); // the hex-encoded transaction hash (aka the transaction id)
+    std::string strHexHash = tx.GetHash().GetHex(); // the hex-encoded transaction hash (aka the transaction id)
 
     fprintf(stdout, "%s\n", strHexHash.c_str());
 }
 
 static void OutputTxHex(const CTransaction& tx)
 {
-    string strHex = EncodeHexTx(tx);
+    std::string strHex = EncodeHexTx(tx);
 
     fprintf(stdout, "%s\n", strHex.c_str());
 }
@@ -593,10 +591,10 @@ static void OutputTx(const CTransaction& tx)
         OutputTxHex(tx);
 }
 
-static string readStdin()
+static std::string readStdin()
 {
     char buf[4096];
-    string ret;
+    std::string ret;
 
     while (!feof(stdin)) {
         size_t bread = fread(buf, 1, sizeof(buf), stdin);
@@ -606,7 +604,7 @@ static string readStdin()
     }
 
     if (ferror(stdin))
-        throw runtime_error("error reading stdin");
+        throw std::runtime_error("error reading stdin");
 
     boost::algorithm::trim_right(ret);
 
@@ -615,7 +613,7 @@ static string readStdin()
 
 static int CommandLineRawTx(int argc, char* argv[])
 {
-    string strPrint;
+    std::string strPrint;
     int nRet = 0;
     try {
         // Skip switches; Permit common stdin convention "-"
@@ -631,15 +629,15 @@ static int CommandLineRawTx(int argc, char* argv[])
         if (!fCreateBlank) {
             // require at least one param
             if (argc < 2)
-                throw runtime_error("too few parameters");
+                throw std::runtime_error("too few parameters");
 
             // param: hex-encoded bitcoin transaction
-            string strHexTx(argv[1]);
+            std::string strHexTx(argv[1]);
             if (strHexTx == "-")                 // "-" implies standard input
                 strHexTx = readStdin();
 
             if (!DecodeHexTx(txDecodeTmp, strHexTx, true))
-                throw runtime_error("invalid transaction encoding");
+                throw std::runtime_error("invalid transaction encoding");
 
             startArg = 2;
         } else
@@ -648,10 +646,10 @@ static int CommandLineRawTx(int argc, char* argv[])
         CMutableTransaction tx(txDecodeTmp);
 
         for (int i = startArg; i < argc; i++) {
-            string arg = argv[i];
-            string key, value;
+            std::string arg = argv[i];
+            std::string key, value;
             size_t eqpos = arg.find('=');
-            if (eqpos == string::npos)
+            if (eqpos == std::string::npos)
                 key = arg;
             else {
                 key = arg.substr(0, eqpos);
@@ -668,7 +666,7 @@ static int CommandLineRawTx(int argc, char* argv[])
         throw;
     }
     catch (const std::exception& e) {
-        strPrint = string("error: ") + e.what();
+        strPrint = std::string("error: ") + e.what();
         nRet = EXIT_FAILURE;
     }
     catch (...) {
diff --git a/src/blockencodings.cpp b/src/blockencodings.cpp
index f14ae1c412..2efeda9cc6 100644
--- a/src/blockencodings.cpp
+++ b/src/blockencodings.cpp
@@ -62,7 +62,7 @@ ReadStatus PartiallyDownloadedBlock::InitData(const CBlockHeaderAndShortTxIDs& c
         if (cmpctblock.prefilledtxn[i].tx->IsNull())
             return READ_STATUS_INVALID;
 
-        lastprefilledindex += cmpctblock.prefilledtxn[i].index + 1; //index is a uint16_t, so cant overflow here
+        lastprefilledindex += cmpctblock.prefilledtxn[i].index + 1; //index is a uint16_t, so can't overflow here
         if (lastprefilledindex > std::numeric_limits<uint16_t>::max())
             return READ_STATUS_INVALID;
         if ((uint32_t)lastprefilledindex > cmpctblock.shorttxids.size() + i) {
diff --git a/src/compat.h b/src/compat.h
index 79a297e5e4..2578d6d344 100644
--- a/src/compat.h
+++ b/src/compat.h
@@ -34,6 +34,7 @@
 #else
 #include <sys/fcntl.h>
 #include <sys/mman.h>
+#include <sys/select.h>
 #include <sys/socket.h>
 #include <sys/types.h>
 #include <net/if.h>
diff --git a/src/crypto/ctaes/test.c b/src/crypto/ctaes/test.c
index fce1696acd..21439a16f1 100644
--- a/src/crypto/ctaes/test.c
+++ b/src/crypto/ctaes/test.c
@@ -102,7 +102,7 @@ int main(void) {
         }
     }
     if (fail == 0) {
-        fprintf(stderr, "All tests succesful\n");
+        fprintf(stderr, "All tests successful\n");
     } else {
         fprintf(stderr, "%i tests failed\n", fail);
     }
diff --git a/src/main.cpp b/src/main.cpp
index d1ff8699e9..452ceac568 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -18,6 +18,7 @@
 #include "init.h"
 #include "merkleblock.h"
 #include "net.h"
+#include "netmessagemaker.h"
 #include "netbase.h"
 #include "policy/fees.h"
 #include "policy/policy.h"
@@ -368,8 +369,8 @@ void PushNodeVersion(CNode *pnode, CConnman& connman, int64_t nTime)
     CAddress addrYou = (addr.IsRoutable() && !IsProxy(addr) ? addr : CAddress(CService(), addr.nServices));
     CAddress addrMe = CAddress(CService(), nLocalNodeServices);
 
-    connman.PushMessageWithVersion(pnode, INIT_PROTO_VERSION, NetMsgType::VERSION, PROTOCOL_VERSION, (uint64_t)nLocalNodeServices, nTime, addrYou, addrMe,
-            nonce, strSubVersion, nNodeStartingHeight, ::fRelayTxes);
+    connman.PushMessage(pnode, CNetMsgMaker(INIT_PROTO_VERSION).Make(NetMsgType::VERSION, PROTOCOL_VERSION, (uint64_t)nLocalNodeServices, nTime, addrYou, addrMe,
+            nonce, strSubVersion, nNodeStartingHeight, ::fRelayTxes));
 
     if (fLogIPs)
         LogPrint("net", "send version message: version %d, blocks=%d, us=%s, them=%s, peer=%d\n", PROTOCOL_VERSION, nNodeStartingHeight, addrMe.ToString(), addrYou.ToString(), nodeid);
@@ -530,13 +531,13 @@ void MaybeSetPeerAsAnnouncingHeaderAndIDs(const CNodeState* nodestate, CNode* pf
             // As per BIP152, we only get 3 of our peers to announce
             // blocks using compact encodings.
             connman.ForNode(lNodesAnnouncingHeaderAndIDs.front(), [&connman, fAnnounceUsingCMPCTBLOCK, nCMPCTBLOCKVersion](CNode* pnodeStop){
-                connman.PushMessage(pnodeStop, NetMsgType::SENDCMPCT, fAnnounceUsingCMPCTBLOCK, nCMPCTBLOCKVersion);
+                connman.PushMessage(pnodeStop, CNetMsgMaker(pnodeStop->GetSendVersion()).Make(NetMsgType::SENDCMPCT, fAnnounceUsingCMPCTBLOCK, nCMPCTBLOCKVersion));
                 return true;
             });
             lNodesAnnouncingHeaderAndIDs.pop_front();
         }
         fAnnounceUsingCMPCTBLOCK = true;
-        connman.PushMessage(pfrom, NetMsgType::SENDCMPCT, fAnnounceUsingCMPCTBLOCK, nCMPCTBLOCKVersion);
+        connman.PushMessage(pfrom, CNetMsgMaker(pfrom->GetSendVersion()).Make(NetMsgType::SENDCMPCT, fAnnounceUsingCMPCTBLOCK, nCMPCTBLOCKVersion));
         lNodesAnnouncingHeaderAndIDs.push_back(pfrom->GetId());
     }
 }
@@ -3511,15 +3512,8 @@ std::vector<unsigned char> GenerateCoinbaseCommitment(CBlock& block, const CBloc
 {
     std::vector<unsigned char> commitment;
     int commitpos = GetWitnessCommitmentIndex(block);
-    bool fHaveWitness = false;
-    for (size_t t = 1; t < block.vtx.size(); t++) {
-        if (!block.vtx[t]->wit.IsNull()) {
-            fHaveWitness = true;
-            break;
-        }
-    }
     std::vector<unsigned char> ret(32, 0x00);
-    if (fHaveWitness && IsWitnessEnabled(pindexPrev, consensusParams)) {
+    if (consensusParams.vDeployments[Consensus::DEPLOYMENT_SEGWIT].nTimeout != 0) {
         if (commitpos == -1) {
             uint256 witnessroot = BlockWitnessMerkleRoot(block, NULL);
             CHash256().Write(witnessroot.begin(), 32).Write(&ret[0], 32).Finalize(witnessroot.begin());
@@ -4893,9 +4887,8 @@ void static ProcessGetData(CNode* pfrom, const Consensus::Params& consensusParam
 {
     std::deque<CInv>::iterator it = pfrom->vRecvGetData.begin();
     unsigned int nMaxSendBufferSize = connman.GetSendBufferSize();
-
     vector<CInv> vNotFound;
-
+    CNetMsgMaker msgMaker(pfrom->GetSendVersion());
     LOCK(cs_main);
 
     while (it != pfrom->vRecvGetData.end()) {
@@ -4949,9 +4942,9 @@ void static ProcessGetData(CNode* pfrom, const Consensus::Params& consensusParam
                     if (!ReadBlockFromDisk(block, (*mi).second, consensusParams))
                         assert(!"cannot load block from disk");
                     if (inv.type == MSG_BLOCK)
-                        connman.PushMessageWithFlag(pfrom, SERIALIZE_TRANSACTION_NO_WITNESS, NetMsgType::BLOCK, block);
+                        connman.PushMessage(pfrom, msgMaker.Make(SERIALIZE_TRANSACTION_NO_WITNESS, NetMsgType::BLOCK, block));
                     else if (inv.type == MSG_WITNESS_BLOCK)
-                        connman.PushMessage(pfrom, NetMsgType::BLOCK, block);
+                        connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::BLOCK, block));
                     else if (inv.type == MSG_FILTERED_BLOCK)
                     {
                         bool sendMerkleBlock = false;
@@ -4964,7 +4957,7 @@ void static ProcessGetData(CNode* pfrom, const Consensus::Params& consensusParam
                             }
                         }
                         if (sendMerkleBlock) {
-                            connman.PushMessage(pfrom, NetMsgType::MERKLEBLOCK, merkleBlock);
+                            connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::MERKLEBLOCK, merkleBlock));
                             // CMerkleBlock just contains hashes, so also push any transactions in the block the client did not see
                             // This avoids hurting performance by pointlessly requiring a round-trip
                             // Note that there is currently no way for a node to request any single transactions we didn't send here -
@@ -4973,7 +4966,7 @@ void static ProcessGetData(CNode* pfrom, const Consensus::Params& consensusParam
                             // however we MUST always provide at least what the remote peer needs
                             typedef std::pair<unsigned int, uint256> PairType;
                             BOOST_FOREACH(PairType& pair, merkleBlock.vMatchedTxn)
-                                connman.PushMessageWithFlag(pfrom, SERIALIZE_TRANSACTION_NO_WITNESS, NetMsgType::TX, *block.vtx[pair.first]);
+                                connman.PushMessage(pfrom, msgMaker.Make(SERIALIZE_TRANSACTION_NO_WITNESS, NetMsgType::TX, *block.vtx[pair.first]));
                         }
                         // else
                             // no response
@@ -4981,15 +4974,16 @@ void static ProcessGetData(CNode* pfrom, const Consensus::Params& consensusParam
                     else if (inv.type == MSG_CMPCT_BLOCK)
                     {
                         // If a peer is asking for old blocks, we're almost guaranteed
-                        // they wont have a useful mempool to match against a compact block,
+                        // they won't have a useful mempool to match against a compact block,
                         // and we don't feel like constructing the object for them, so
                         // instead we respond with the full, non-compact block.
                         bool fPeerWantsWitness = State(pfrom->GetId())->fWantsCmpctWitness;
+                        int nSendFlags = fPeerWantsWitness ? 0 : SERIALIZE_TRANSACTION_NO_WITNESS;
                         if (CanDirectFetch(consensusParams) && mi->second->nHeight >= chainActive.Height() - MAX_CMPCTBLOCK_DEPTH) {
                             CBlockHeaderAndShortTxIDs cmpctblock(block, fPeerWantsWitness);
-                            connman.PushMessageWithFlag(pfrom, fPeerWantsWitness ? 0 : SERIALIZE_TRANSACTION_NO_WITNESS, NetMsgType::CMPCTBLOCK, cmpctblock);
+                            connman.PushMessage(pfrom, msgMaker.Make(nSendFlags, NetMsgType::CMPCTBLOCK, cmpctblock));
                         } else
-                            connman.PushMessageWithFlag(pfrom, fPeerWantsWitness ? 0 : SERIALIZE_TRANSACTION_NO_WITNESS, NetMsgType::BLOCK, block);
+                            connman.PushMessage(pfrom, msgMaker.Make(nSendFlags, NetMsgType::BLOCK, block));
                     }
 
                     // Trigger the peer node to send a getblocks request for the next batch of inventory
@@ -5000,7 +4994,7 @@ void static ProcessGetData(CNode* pfrom, const Consensus::Params& consensusParam
                         // wait for other stuff first.
                         vector<CInv> vInv;
                         vInv.push_back(CInv(MSG_BLOCK, chainActive.Tip()->GetBlockHash()));
-                        connman.PushMessage(pfrom, NetMsgType::INV, vInv);
+                        connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::INV, vInv));
                         pfrom->hashContinue.SetNull();
                     }
                 }
@@ -5010,15 +5004,16 @@ void static ProcessGetData(CNode* pfrom, const Consensus::Params& consensusParam
                 // Send stream from relay memory
                 bool push = false;
                 auto mi = mapRelay.find(inv.hash);
+                int nSendFlags = (inv.type == MSG_TX ? SERIALIZE_TRANSACTION_NO_WITNESS : 0);
                 if (mi != mapRelay.end()) {
-                    connman.PushMessageWithFlag(pfrom, inv.type == MSG_TX ? SERIALIZE_TRANSACTION_NO_WITNESS : 0, NetMsgType::TX, *mi->second);
+                    connman.PushMessage(pfrom, msgMaker.Make(nSendFlags, NetMsgType::TX, *mi->second));
                     push = true;
                 } else if (pfrom->timeLastMempoolReq) {
                     auto txinfo = mempool.info(inv.hash);
                     // To protect privacy, do not answer getdata using the mempool when
                     // that TX couldn't have been INVed in reply to a MEMPOOL request.
                     if (txinfo.tx && txinfo.nTime <= pfrom->timeLastMempoolReq) {
-                        connman.PushMessageWithFlag(pfrom, inv.type == MSG_TX ? SERIALIZE_TRANSACTION_NO_WITNESS : 0, NetMsgType::TX, *txinfo.tx);
+                        connman.PushMessage(pfrom, msgMaker.Make(nSendFlags, NetMsgType::TX, *txinfo.tx));
                         push = true;
                     }
                 }
@@ -5045,7 +5040,7 @@ void static ProcessGetData(CNode* pfrom, const Consensus::Params& consensusParam
         // do that because they want to know about (and store and rebroadcast and
         // risk analyze) the dependencies of transactions relevant to them, without
         // having to download the entire memory pool.
-        connman.PushMessage(pfrom, NetMsgType::NOTFOUND, vNotFound);
+        connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::NOTFOUND, vNotFound));
     }
 }
 
@@ -5086,16 +5081,10 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
 
     if (strCommand == NetMsgType::VERSION)
     {
-        // Feeler connections exist only to verify if address is online.
-        if (pfrom->fFeeler) {
-            assert(pfrom->fInbound == false);
-            pfrom->fDisconnect = true;
-        }
-
         // Each connection can only send one version message
         if (pfrom->nVersion != 0)
         {
-            connman.PushMessageWithVersion(pfrom, INIT_PROTO_VERSION, NetMsgType::REJECT, strCommand, REJECT_DUPLICATE, string("Duplicate version message"));
+            connman.PushMessage(pfrom, CNetMsgMaker(INIT_PROTO_VERSION).Make(NetMsgType::REJECT, strCommand, REJECT_DUPLICATE, string("Duplicate version message")));
             LOCK(cs_main);
             Misbehaving(pfrom->GetId(), 1);
             return false;
@@ -5115,8 +5104,8 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
         if (pfrom->nServicesExpected & ~pfrom->nServices)
         {
             LogPrint("net", "peer=%d does not offer the expected services (%08x offered, %08x expected); disconnecting\n", pfrom->id, pfrom->nServices, pfrom->nServicesExpected);
-            connman.PushMessageWithVersion(pfrom, INIT_PROTO_VERSION, NetMsgType::REJECT, strCommand, REJECT_NONSTANDARD,
-                               strprintf("Expected to offer services %08x", pfrom->nServicesExpected));
+            connman.PushMessage(pfrom, CNetMsgMaker(INIT_PROTO_VERSION).Make(NetMsgType::REJECT, strCommand, REJECT_NONSTANDARD,
+                               strprintf("Expected to offer services %08x", pfrom->nServicesExpected)));
             pfrom->fDisconnect = true;
             return false;
         }
@@ -5125,8 +5114,8 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
         {
             // disconnect from peers older than this proto version
             LogPrintf("peer=%d using obsolete version %i; disconnecting\n", pfrom->id, pfrom->nVersion);
-            connman.PushMessageWithVersion(pfrom, INIT_PROTO_VERSION, NetMsgType::REJECT, strCommand, REJECT_OBSOLETE,
-                               strprintf("Version must be %d or greater", MIN_PEER_PROTO_VERSION));
+            connman.PushMessage(pfrom, CNetMsgMaker(INIT_PROTO_VERSION).Make(NetMsgType::REJECT, strCommand, REJECT_OBSOLETE,
+                               strprintf("Version must be %d or greater", MIN_PEER_PROTO_VERSION)));
             pfrom->fDisconnect = true;
             return false;
         }
@@ -5183,8 +5172,9 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
         }
 
         // Change version
-        connman.PushMessageWithVersion(pfrom, INIT_PROTO_VERSION, NetMsgType::VERACK);
-        pfrom->SetSendVersion(min(pfrom->nVersion, PROTOCOL_VERSION));
+        connman.PushMessage(pfrom, CNetMsgMaker(INIT_PROTO_VERSION).Make(NetMsgType::VERACK));
+        int nSendVersion = std::min(pfrom->nVersion, PROTOCOL_VERSION);
+        pfrom->SetSendVersion(nSendVersion);
 
         if (!pfrom->fInbound)
         {
@@ -5207,7 +5197,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
             // Get recent addresses
             if (pfrom->fOneShot || pfrom->nVersion >= CADDR_TIME_VERSION || connman.GetAddressCount() < 1000)
             {
-                connman.PushMessage(pfrom, NetMsgType::GETADDR);
+                connman.PushMessage(pfrom, CNetMsgMaker(nSendVersion).Make(NetMsgType::GETADDR));
                 pfrom->fGetAddr = true;
             }
             connman.MarkAddressGood(pfrom->addr);
@@ -5227,6 +5217,13 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
         int64_t nTimeOffset = nTime - GetTime();
         pfrom->nTimeOffset = nTimeOffset;
         AddTimeData(pfrom->addr, nTimeOffset);
+
+        // Feeler connections exist only to verify if address is online.
+        if (pfrom->fFeeler) {
+            assert(pfrom->fInbound == false);
+            pfrom->fDisconnect = true;
+        }
+        return true;
     }
 
 
@@ -5238,8 +5235,10 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
         return false;
     }
 
+    // At this point, the outgoing message serialization version can't change.
+    CNetMsgMaker msgMaker(pfrom->GetSendVersion());
 
-    else if (strCommand == NetMsgType::VERACK)
+    if (strCommand == NetMsgType::VERACK)
     {
         pfrom->SetRecvVersion(min(pfrom->nVersion, PROTOCOL_VERSION));
 
@@ -5254,7 +5253,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
             // We send this to non-NODE NETWORK peers as well, because even
             // non-NODE NETWORK peers can announce blocks (such as pruning
             // nodes)
-            connman.PushMessage(pfrom, NetMsgType::SENDHEADERS);
+            connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::SENDHEADERS));
         }
         if (pfrom->nVersion >= SHORT_IDS_BLOCKS_VERSION) {
             // Tell our peer we are willing to provide version 1 or 2 cmpctblocks
@@ -5265,9 +5264,9 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
             bool fAnnounceUsingCMPCTBLOCK = false;
             uint64_t nCMPCTBLOCKVersion = 2;
             if (pfrom->GetLocalServices() & NODE_WITNESS)
-                connman.PushMessage(pfrom, NetMsgType::SENDCMPCT, fAnnounceUsingCMPCTBLOCK, nCMPCTBLOCKVersion);
+                connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::SENDCMPCT, fAnnounceUsingCMPCTBLOCK, nCMPCTBLOCKVersion));
             nCMPCTBLOCKVersion = 1;
-            connman.PushMessage(pfrom, NetMsgType::SENDCMPCT, fAnnounceUsingCMPCTBLOCK, nCMPCTBLOCKVersion);
+            connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::SENDCMPCT, fAnnounceUsingCMPCTBLOCK, nCMPCTBLOCKVersion));
         }
     }
 
@@ -5392,7 +5391,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
                     // fell back to inv we probably have a reorg which we should get the headers for first,
                     // we now only provide a getheaders response here. When we receive the headers, we will
                     // then ask for the blocks we need.
-                    connman.PushMessage(pfrom, NetMsgType::GETHEADERS, chainActive.GetLocator(pindexBestHeader), inv.hash);
+                    connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::GETHEADERS, chainActive.GetLocator(pindexBestHeader), inv.hash));
                     LogPrint("net", "getheaders (%d) %s to peer=%d\n", pindexBestHeader->nHeight, inv.hash.ToString(), pfrom->id);
                 }
             }
@@ -5415,7 +5414,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
         }
 
         if (!vToFetch.empty())
-            connman.PushMessage(pfrom, NetMsgType::GETDATA, vToFetch);
+            connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::GETDATA, vToFetch));
     }
 
 
@@ -5527,7 +5526,8 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
             }
             resp.txn[i] = block.vtx[req.indexes[i]];
         }
-        connman.PushMessageWithFlag(pfrom, State(pfrom->GetId())->fWantsCmpctWitness ? 0 : SERIALIZE_TRANSACTION_NO_WITNESS, NetMsgType::BLOCKTXN, resp);
+        int nSendFlags = State(pfrom->GetId())->fWantsCmpctWitness ? 0 : SERIALIZE_TRANSACTION_NO_WITNESS;
+        connman.PushMessage(pfrom, msgMaker.Make(nSendFlags, NetMsgType::BLOCKTXN, resp));
     }
 
 
@@ -5576,7 +5576,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
         // headers message). In both cases it's safe to update
         // pindexBestHeaderSent to be our tip.
         nodestate->pindexBestHeaderSent = pindex ? pindex : chainActive.Tip();
-        connman.PushMessage(pfrom, NetMsgType::HEADERS, vHeaders);
+        connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::HEADERS, vHeaders));
     }
 
 
@@ -5739,8 +5739,8 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
                 pfrom->id,
                 FormatStateMessage(state));
             if (state.GetRejectCode() < REJECT_INTERNAL) // Never send AcceptToMemoryPool's internal codes over P2P
-                connman.PushMessage(pfrom, NetMsgType::REJECT, strCommand, (unsigned char)state.GetRejectCode(),
-                                   state.GetRejectReason().substr(0, MAX_REJECT_MESSAGE_LENGTH), inv.hash);
+                connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::REJECT, strCommand, (unsigned char)state.GetRejectCode(),
+                                   state.GetRejectReason().substr(0, MAX_REJECT_MESSAGE_LENGTH), inv.hash));
             if (nDoS > 0) {
                 Misbehaving(pfrom->GetId(), nDoS);
             }
@@ -5758,7 +5758,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
         if (mapBlockIndex.find(cmpctblock.header.hashPrevBlock) == mapBlockIndex.end()) {
             // Doesn't connect (or is genesis), instead of DoSing in AcceptBlockHeader, request deeper headers
             if (!IsInitialBlockDownload())
-                connman.PushMessage(pfrom, NetMsgType::GETHEADERS, chainActive.GetLocator(pindexBestHeader), uint256());
+                connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::GETHEADERS, chainActive.GetLocator(pindexBestHeader), uint256()));
             return true;
         }
 
@@ -5791,7 +5791,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
                 // so we just grab the block via normal getdata
                 std::vector<CInv> vInv(1);
                 vInv[0] = CInv(MSG_BLOCK | GetFetchFlags(pfrom, pindex->pprev, chainparams.GetConsensus()), cmpctblock.header.GetHash());
-                connman.PushMessage(pfrom, NetMsgType::GETDATA, vInv);
+                connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::GETDATA, vInv));
             }
             return true;
         }
@@ -5835,7 +5835,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
                     // Duplicate txindexes, the block is now in-flight, so just request it
                     std::vector<CInv> vInv(1);
                     vInv[0] = CInv(MSG_BLOCK | GetFetchFlags(pfrom, pindex->pprev, chainparams.GetConsensus()), cmpctblock.header.GetHash());
-                    connman.PushMessage(pfrom, NetMsgType::GETDATA, vInv);
+                    connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::GETDATA, vInv));
                     return true;
                 }
 
@@ -5859,7 +5859,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
                     return ProcessMessage(pfrom, NetMsgType::BLOCKTXN, blockTxnMsg, nTimeReceived, chainparams, connman);
                 } else {
                     req.blockhash = pindex->GetBlockHash();
-                    connman.PushMessage(pfrom, NetMsgType::GETBLOCKTXN, req);
+                    connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::GETBLOCKTXN, req));
                 }
             }
         } else {
@@ -5868,7 +5868,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
                 // mempool will probably be useless - request the block normally
                 std::vector<CInv> vInv(1);
                 vInv[0] = CInv(MSG_BLOCK | GetFetchFlags(pfrom, pindex->pprev, chainparams.GetConsensus()), cmpctblock.header.GetHash());
-                connman.PushMessage(pfrom, NetMsgType::GETDATA, vInv);
+                connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::GETDATA, vInv));
                 return true;
             } else {
                 // If this was an announce-cmpctblock, we want the same treatment as a header message
@@ -5910,7 +5910,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
                 // Might have collided, fall back to getdata now :(
                 std::vector<CInv> invs;
                 invs.push_back(CInv(MSG_BLOCK | GetFetchFlags(pfrom, chainActive.Tip(), chainparams.GetConsensus()), resp.blockhash));
-                connman.PushMessage(pfrom, NetMsgType::GETDATA, invs);
+                connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::GETDATA, invs));
             } else {
                 // Block is either okay, or possibly we received
                 // READ_STATUS_CHECKBLOCK_FAILED.
@@ -5987,7 +5987,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
         //   nUnconnectingHeaders gets reset back to 0.
         if (mapBlockIndex.find(headers[0].hashPrevBlock) == mapBlockIndex.end() && nCount < MAX_BLOCKS_TO_ANNOUNCE) {
             nodestate->nUnconnectingHeaders++;
-            connman.PushMessage(pfrom, NetMsgType::GETHEADERS, chainActive.GetLocator(pindexBestHeader), uint256());
+            connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::GETHEADERS, chainActive.GetLocator(pindexBestHeader), uint256()));
             LogPrint("net", "received header %s: missing prev block %s, sending getheaders (%d) to end (peer=%d, nUnconnectingHeaders=%d)\n",
                     headers[0].GetHash().ToString(),
                     headers[0].hashPrevBlock.ToString(),
@@ -6034,7 +6034,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
             // TODO: optimize: if pindexLast is an ancestor of chainActive.Tip or pindexBestHeader, continue
             // from there instead.
             LogPrint("net", "more getheaders (%d) to end to peer=%d (startheight:%d)\n", pindexLast->nHeight, pfrom->id, pfrom->nStartingHeight);
-            connman.PushMessage(pfrom, NetMsgType::GETHEADERS, chainActive.GetLocator(pindexLast), uint256());
+            connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::GETHEADERS, chainActive.GetLocator(pindexLast), uint256()));
         }
 
         bool fCanDirectFetch = CanDirectFetch(chainparams.GetConsensus());
@@ -6087,7 +6087,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
                         // In any case, we want to download using a compact block, not a regular one
                         vGetData[0] = CInv(MSG_CMPCT_BLOCK, vGetData[0].hash);
                     }
-                    connman.PushMessage(pfrom, NetMsgType::GETDATA, vGetData);
+                    connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::GETDATA, vGetData));
                 }
             }
         }
@@ -6191,7 +6191,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
             // it, if the remote node sends a ping once per second and this node takes 5
             // seconds to respond to each, the 5th ping the remote sends would appear to
             // return very quickly.
-            connman.PushMessage(pfrom, NetMsgType::PONG, nonce);
+            connman.PushMessage(pfrom, msgMaker.Make(NetMsgType::PONG, nonce));
         }
     }
 
@@ -6447,7 +6447,7 @@ bool ProcessMessages(CNode* pfrom, CConnman& connman)
         }
         catch (const std::ios_base::failure& e)
         {
-            connman.PushMessageWithVersion(pfrom, INIT_PROTO_VERSION, NetMsgType::REJECT, strCommand, REJECT_MALFORMED, string("error parsing message"));
+            connman.PushMessage(pfrom, CNetMsgMaker(INIT_PROTO_VERSION).Make(NetMsgType::REJECT, strCommand, REJECT_MALFORMED, string("error parsing message")));
             if (strstr(e.what(), "end of data"))
             {
                 // Allow exceptions from under-length message on vRecv
@@ -6512,9 +6512,12 @@ bool SendMessages(CNode* pto, CConnman& connman)
     const Consensus::Params& consensusParams = Params().GetConsensus();
     {
         // Don't send anything until we get its version message
-        if (pto->nVersion == 0)
+        if (pto->nVersion == 0 || pto->fDisconnect)
             return true;
 
+        // If we get here, the outgoing message serialization version is set and can't change.
+        CNetMsgMaker msgMaker(pto->GetSendVersion());
+
         //
         // Message: ping
         //
@@ -6527,7 +6530,7 @@ bool SendMessages(CNode* pto, CConnman& connman)
             // Ping automatically sent as a latency probe & keepalive.
             pingSend = true;
         }
-        if (pingSend && !pto->fDisconnect) {
+        if (pingSend) {
             uint64_t nonce = 0;
             while (nonce == 0) {
                 GetRandBytes((unsigned char*)&nonce, sizeof(nonce));
@@ -6536,11 +6539,11 @@ bool SendMessages(CNode* pto, CConnman& connman)
             pto->nPingUsecStart = GetTimeMicros();
             if (pto->nVersion > BIP0031_VERSION) {
                 pto->nPingNonceSent = nonce;
-                connman.PushMessage(pto, NetMsgType::PING, nonce);
+                connman.PushMessage(pto, msgMaker.Make(NetMsgType::PING, nonce));
             } else {
                 // Peer is too old to support ping command with nonce, pong will never arrive.
                 pto->nPingNonceSent = 0;
-                connman.PushMessage(pto, NetMsgType::PING);
+                connman.PushMessage(pto, msgMaker.Make(NetMsgType::PING));
             }
         }
 
@@ -6548,6 +6551,28 @@ bool SendMessages(CNode* pto, CConnman& connman)
         if (!lockMain)
             return true;
 
+        CNodeState &state = *State(pto->GetId());
+
+        BOOST_FOREACH(const CBlockReject& reject, state.rejects)
+            connman.PushMessage(pto, msgMaker.Make(NetMsgType::REJECT, (string)NetMsgType::BLOCK, reject.chRejectCode, reject.strRejectReason, reject.hashBlock));
+        state.rejects.clear();
+
+        if (state.fShouldBan) {
+            state.fShouldBan = false;
+            if (pto->fWhitelisted)
+                LogPrintf("Warning: not punishing whitelisted peer %s!\n", pto->addr.ToString());
+            else {
+                pto->fDisconnect = true;
+                if (pto->addr.IsLocal())
+                    LogPrintf("Warning: not banning local peer %s!\n", pto->addr.ToString());
+                else
+                {
+                    connman.Ban(pto->addr, BanReasonNodeMisbehaving);
+                }
+                return true;
+            }
+        }
+
         // Address refresh broadcast
         int64_t nNow = GetTimeMicros();
         if (!IsInitialBlockDownload() && pto->nNextLocalAddrSend < nNow) {
@@ -6571,44 +6596,24 @@ bool SendMessages(CNode* pto, CConnman& connman)
                     // receiver rejects addr messages larger than 1000
                     if (vAddr.size() >= 1000)
                     {
-                        connman.PushMessage(pto, NetMsgType::ADDR, vAddr);
+                        connman.PushMessage(pto, msgMaker.Make(NetMsgType::ADDR, vAddr));
                         vAddr.clear();
                     }
                 }
             }
             pto->vAddrToSend.clear();
             if (!vAddr.empty())
-                connman.PushMessage(pto, NetMsgType::ADDR, vAddr);
+                connman.PushMessage(pto, msgMaker.Make(NetMsgType::ADDR, vAddr));
             // we only send the big addr message once
             if (pto->vAddrToSend.capacity() > 40)
                 pto->vAddrToSend.shrink_to_fit();
         }
 
-        CNodeState &state = *State(pto->GetId());
-        if (state.fShouldBan) {
-            if (pto->fWhitelisted)
-                LogPrintf("Warning: not punishing whitelisted peer %s!\n", pto->addr.ToString());
-            else {
-                pto->fDisconnect = true;
-                if (pto->addr.IsLocal())
-                    LogPrintf("Warning: not banning local peer %s!\n", pto->addr.ToString());
-                else
-                {
-                    connman.Ban(pto->addr, BanReasonNodeMisbehaving);
-                }
-            }
-            state.fShouldBan = false;
-        }
-
-        BOOST_FOREACH(const CBlockReject& reject, state.rejects)
-            connman.PushMessage(pto, NetMsgType::REJECT, (string)NetMsgType::BLOCK, reject.chRejectCode, reject.strRejectReason, reject.hashBlock);
-        state.rejects.clear();
-
         // Start block sync
         if (pindexBestHeader == NULL)
             pindexBestHeader = chainActive.Tip();
         bool fFetch = state.fPreferredDownload || (nPreferredDownload == 0 && !pto->fClient && !pto->fOneShot); // Download if this is a nice peer, or we have no nice peers and this one might do.
-        if (!state.fSyncStarted && !pto->fClient && !pto->fDisconnect && !fImporting && !fReindex) {
+        if (!state.fSyncStarted && !pto->fClient && !fImporting && !fReindex) {
             // Only actively request headers from a single peer, unless we're close to today.
             if ((nSyncStarted == 0 && fFetch) || pindexBestHeader->GetBlockTime() > GetAdjustedTime() - 24 * 60 * 60) {
                 state.fSyncStarted = true;
@@ -6624,7 +6629,7 @@ bool SendMessages(CNode* pto, CConnman& connman)
                 if (pindexStart->pprev)
                     pindexStart = pindexStart->pprev;
                 LogPrint("net", "initial getheaders (%d) to peer=%d (startheight:%d)\n", pindexStart->nHeight, pto->id, pto->nStartingHeight);
-                connman.PushMessage(pto, NetMsgType::GETHEADERS, chainActive.GetLocator(pindexStart), uint256());
+                connman.PushMessage(pto, msgMaker.Make(NetMsgType::GETHEADERS, chainActive.GetLocator(pindexStart), uint256()));
             }
         }
 
@@ -6713,7 +6718,8 @@ bool SendMessages(CNode* pto, CConnman& connman)
                     CBlock block;
                     assert(ReadBlockFromDisk(block, pBestIndex, consensusParams));
                     CBlockHeaderAndShortTxIDs cmpctblock(block, state.fWantsCmpctWitness);
-                    connman.PushMessageWithFlag(pto, state.fWantsCmpctWitness ? 0 : SERIALIZE_TRANSACTION_NO_WITNESS, NetMsgType::CMPCTBLOCK, cmpctblock);
+                    int nSendFlags = state.fWantsCmpctWitness ? 0 : SERIALIZE_TRANSACTION_NO_WITNESS;
+                    connman.PushMessage(pto, msgMaker.Make(nSendFlags, NetMsgType::CMPCTBLOCK, cmpctblock));
                     state.pindexBestHeaderSent = pBestIndex;
                 } else if (state.fPreferHeaders) {
                     if (vHeaders.size() > 1) {
@@ -6725,7 +6731,7 @@ bool SendMessages(CNode* pto, CConnman& connman)
                         LogPrint("net", "%s: sending header %s to peer=%d\n", __func__,
                                 vHeaders.front().GetHash().ToString(), pto->id);
                     }
-                    connman.PushMessage(pto, NetMsgType::HEADERS, vHeaders);
+                    connman.PushMessage(pto, msgMaker.Make(NetMsgType::HEADERS, vHeaders));
                     state.pindexBestHeaderSent = pBestIndex;
                 } else
                     fRevertToInv = true;
@@ -6771,7 +6777,7 @@ bool SendMessages(CNode* pto, CConnman& connman)
             BOOST_FOREACH(const uint256& hash, pto->vInventoryBlockToSend) {
                 vInv.push_back(CInv(MSG_BLOCK, hash));
                 if (vInv.size() == MAX_INV_SZ) {
-                    connman.PushMessage(pto, NetMsgType::INV, vInv);
+                    connman.PushMessage(pto, msgMaker.Make(NetMsgType::INV, vInv));
                     vInv.clear();
                 }
             }
@@ -6817,7 +6823,7 @@ bool SendMessages(CNode* pto, CConnman& connman)
                     pto->filterInventoryKnown.insert(hash);
                     vInv.push_back(inv);
                     if (vInv.size() == MAX_INV_SZ) {
-                        connman.PushMessage(pto, NetMsgType::INV, vInv);
+                        connman.PushMessage(pto, msgMaker.Make(NetMsgType::INV, vInv));
                         vInv.clear();
                     }
                 }
@@ -6883,7 +6889,7 @@ bool SendMessages(CNode* pto, CConnman& connman)
                         }
                     }
                     if (vInv.size() == MAX_INV_SZ) {
-                        connman.PushMessage(pto, NetMsgType::INV, vInv);
+                        connman.PushMessage(pto, msgMaker.Make(NetMsgType::INV, vInv));
                         vInv.clear();
                     }
                     pto->filterInventoryKnown.insert(hash);
@@ -6891,28 +6897,30 @@ bool SendMessages(CNode* pto, CConnman& connman)
             }
         }
         if (!vInv.empty())
-            connman.PushMessage(pto, NetMsgType::INV, vInv);
+            connman.PushMessage(pto, msgMaker.Make(NetMsgType::INV, vInv));
 
         // Detect whether we're stalling
         nNow = GetTimeMicros();
-        if (!pto->fDisconnect && state.nStallingSince && state.nStallingSince < nNow - 1000000 * BLOCK_STALLING_TIMEOUT) {
+        if (state.nStallingSince && state.nStallingSince < nNow - 1000000 * BLOCK_STALLING_TIMEOUT) {
             // Stalling only triggers when the block download window cannot move. During normal steady state,
             // the download window should be much larger than the to-be-downloaded set of blocks, so disconnection
             // should only happen during initial block download.
             LogPrintf("Peer=%d is stalling block download, disconnecting\n", pto->id);
             pto->fDisconnect = true;
+            return true;
         }
         // In case there is a block that has been in flight from this peer for 2 + 0.5 * N times the block interval
         // (with N the number of peers from which we're downloading validated blocks), disconnect due to timeout.
         // We compensate for other peers to prevent killing off peers due to our own downstream link
         // being saturated. We only count validated in-flight blocks so peers can't advertise non-existing block hashes
         // to unreasonably increase our timeout.
-        if (!pto->fDisconnect && state.vBlocksInFlight.size() > 0) {
+        if (state.vBlocksInFlight.size() > 0) {
             QueuedBlock &queuedBlock = state.vBlocksInFlight.front();
             int nOtherPeersWithValidatedDownloads = nPeersWithValidatedDownloads - (state.nBlocksInFlightValidHeaders > 0);
             if (nNow > state.nDownloadingSince + consensusParams.nPowTargetSpacing * (BLOCK_DOWNLOAD_TIMEOUT_BASE + BLOCK_DOWNLOAD_TIMEOUT_PER_PEER * nOtherPeersWithValidatedDownloads)) {
                 LogPrintf("Timeout downloading block %s from peer=%d, disconnecting\n", queuedBlock.hash.ToString(), pto->id);
                 pto->fDisconnect = true;
+                return true;
             }
         }
 
@@ -6920,7 +6928,7 @@ bool SendMessages(CNode* pto, CConnman& connman)
         // Message: getdata (blocks)
         //
         vector<CInv> vGetData;
-        if (!pto->fDisconnect && !pto->fClient && (fFetch || !IsInitialBlockDownload()) && state.nBlocksInFlight < MAX_BLOCKS_IN_TRANSIT_PER_PEER) {
+        if (!pto->fClient && (fFetch || !IsInitialBlockDownload()) && state.nBlocksInFlight < MAX_BLOCKS_IN_TRANSIT_PER_PEER) {
             vector<CBlockIndex*> vToDownload;
             NodeId staller = -1;
             FindNextBlocksToDownload(pto->GetId(), MAX_BLOCKS_IN_TRANSIT_PER_PEER - state.nBlocksInFlight, vToDownload, staller, consensusParams);
@@ -6942,7 +6950,7 @@ bool SendMessages(CNode* pto, CConnman& connman)
         //
         // Message: getdata (non-blocks)
         //
-        while (!pto->fDisconnect && !pto->mapAskFor.empty() && (*pto->mapAskFor.begin()).first <= nNow)
+        while (!pto->mapAskFor.empty() && (*pto->mapAskFor.begin()).first <= nNow)
         {
             const CInv& inv = (*pto->mapAskFor.begin()).second;
             if (!AlreadyHave(inv))
@@ -6952,7 +6960,7 @@ bool SendMessages(CNode* pto, CConnman& connman)
                 vGetData.push_back(inv);
                 if (vGetData.size() >= 1000)
                 {
-                    connman.PushMessage(pto, NetMsgType::GETDATA, vGetData);
+                    connman.PushMessage(pto, msgMaker.Make(NetMsgType::GETDATA, vGetData));
                     vGetData.clear();
                 }
             } else {
@@ -6962,20 +6970,20 @@ bool SendMessages(CNode* pto, CConnman& connman)
             pto->mapAskFor.erase(pto->mapAskFor.begin());
         }
         if (!vGetData.empty())
-            connman.PushMessage(pto, NetMsgType::GETDATA, vGetData);
+            connman.PushMessage(pto, msgMaker.Make(NetMsgType::GETDATA, vGetData));
 
         //
         // Message: feefilter
         //
         // We don't want white listed peers to filter txs to us if we have -whitelistforcerelay
-        if (!pto->fDisconnect && pto->nVersion >= FEEFILTER_VERSION && GetBoolArg("-feefilter", DEFAULT_FEEFILTER) &&
+        if (pto->nVersion >= FEEFILTER_VERSION && GetBoolArg("-feefilter", DEFAULT_FEEFILTER) &&
             !(pto->fWhitelisted && GetBoolArg("-whitelistforcerelay", DEFAULT_WHITELISTFORCERELAY))) {
             CAmount currentFilter = mempool.GetMinFee(GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000).GetFeePerK();
             int64_t timeNow = GetTimeMicros();
             if (timeNow > pto->nextSendTimeFeeFilter) {
                 CAmount filterToSend = filterRounder.round(currentFilter);
                 if (filterToSend != pto->lastSentFeeFilter) {
-                    connman.PushMessage(pto, NetMsgType::FEEFILTER, filterToSend);
+                    connman.PushMessage(pto, msgMaker.Make(NetMsgType::FEEFILTER, filterToSend));
                     pto->lastSentFeeFilter = filterToSend;
                 }
                 pto->nextSendTimeFeeFilter = PoissonNextSend(timeNow, AVG_FEEFILTER_BROADCAST_INTERVAL);
diff --git a/src/net.cpp b/src/net.cpp
index 233c0fbc80..ba74cd071e 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -768,13 +768,13 @@ const uint256& CNetMessage::GetMessageHash() const
 // requires LOCK(cs_vSend)
 size_t SocketSendData(CNode *pnode)
 {
-    std::deque<CSerializeData>::iterator it = pnode->vSendMsg.begin();
+    auto it = pnode->vSendMsg.begin();
     size_t nSentSize = 0;
 
     while (it != pnode->vSendMsg.end()) {
-        const CSerializeData &data = *it;
+        const auto &data = *it;
         assert(data.size() > pnode->nSendOffset);
-        int nBytes = send(pnode->hSocket, &data[pnode->nSendOffset], data.size() - pnode->nSendOffset, MSG_NOSIGNAL | MSG_DONTWAIT);
+        int nBytes = send(pnode->hSocket, reinterpret_cast<const char*>(data.data()) + pnode->nSendOffset, data.size() - pnode->nSendOffset, MSG_NOSIGNAL | MSG_DONTWAIT);
         if (nBytes > 0) {
             pnode->nLastSend = GetTime();
             pnode->nSendBytes += nBytes;
@@ -2617,30 +2617,19 @@ void CNode::AskFor(const CInv& inv)
     mapAskFor.insert(std::make_pair(nRequestTime, inv));
 }
 
-CDataStream CConnman::BeginMessage(CNode* pnode, int nVersion, int flags, const std::string& sCommand)
+void CConnman::PushMessage(CNode* pnode, CSerializedNetMsg&& msg)
 {
-    return {SER_NETWORK, (nVersion ? nVersion : pnode->GetSendVersion()) | flags, CMessageHeader(Params().MessageStart(), sCommand.c_str(), 0) };
-}
-
-void CConnman::EndMessage(CDataStream& strm)
-{
-    // Set the size
-    assert(strm.size () >= CMessageHeader::HEADER_SIZE);
-    unsigned int nSize = strm.size() - CMessageHeader::HEADER_SIZE;
-    WriteLE32((uint8_t*)&strm[CMessageHeader::MESSAGE_SIZE_OFFSET], nSize);
-    // Set the checksum
-    uint256 hash = Hash(strm.begin() + CMessageHeader::HEADER_SIZE, strm.end());
-    memcpy((char*)&strm[CMessageHeader::CHECKSUM_OFFSET], hash.begin(), CMessageHeader::CHECKSUM_SIZE);
-
-}
+    size_t nMessageSize = msg.data.size();
+    size_t nTotalSize = nMessageSize + CMessageHeader::HEADER_SIZE;
+    LogPrint("net", "sending %s (%d bytes) peer=%d\n",  SanitizeString(msg.command.c_str()), nMessageSize, pnode->id);
 
-void CConnman::PushMessage(CNode* pnode, CDataStream& strm, const std::string& sCommand)
-{
-    if(strm.empty())
-        return;
+    std::vector<unsigned char> serializedHeader;
+    serializedHeader.reserve(CMessageHeader::HEADER_SIZE);
+    uint256 hash = Hash(msg.data.data(), msg.data.data() + nMessageSize);
+    CMessageHeader hdr(Params().MessageStart(), msg.command.c_str(), nMessageSize);
+    memcpy(hdr.pchChecksum, hash.begin(), CMessageHeader::CHECKSUM_SIZE);
 
-    unsigned int nSize = strm.size() - CMessageHeader::HEADER_SIZE;
-    LogPrint("net", "sending %s (%d bytes) peer=%d\n",  SanitizeString(sCommand.c_str()), nSize, pnode->id);
+    CVectorWriter{SER_NETWORK, INIT_PROTO_VERSION, serializedHeader, 0, hdr};
 
     size_t nBytesSent = 0;
     {
@@ -2649,11 +2638,14 @@ void CConnman::PushMessage(CNode* pnode, CDataStream& strm, const std::string& s
             return;
         }
         bool optimisticSend(pnode->vSendMsg.empty());
-        pnode->vSendMsg.emplace_back(strm.begin(), strm.end());
 
         //log total amount of bytes per command
-        pnode->mapSendBytesPerMsgCmd[sCommand] += strm.size();
-        pnode->nSendSize += strm.size();
+        pnode->mapSendBytesPerMsgCmd[msg.command] += nTotalSize;
+        pnode->nSendSize += nTotalSize;
+
+        pnode->vSendMsg.push_back(std::move(serializedHeader));
+        if (nMessageSize)
+            pnode->vSendMsg.push_back(std::move(msg.data));
 
         // If write queue empty, attempt "optimistic write"
         if (optimisticSend == true)
diff --git a/src/net.h b/src/net.h
index 31385c231e..df3930d82e 100644
--- a/src/net.h
+++ b/src/net.h
@@ -101,6 +101,20 @@ class CTransaction;
 class CNodeStats;
 class CClientUIInterface;
 
+struct CSerializedNetMsg
+{
+    CSerializedNetMsg() = default;
+    CSerializedNetMsg(CSerializedNetMsg&&) = default;
+    CSerializedNetMsg& operator=(CSerializedNetMsg&&) = default;
+    // No copying, only moves.
+    CSerializedNetMsg(const CSerializedNetMsg& msg) = delete;
+    CSerializedNetMsg& operator=(const CSerializedNetMsg&) = delete;
+
+    std::vector<unsigned char> data;
+    std::string command;
+};
+
+
 class CConnman
 {
 public:
@@ -138,32 +152,7 @@ public:
 
     bool ForNode(NodeId id, std::function<bool(CNode* pnode)> func);
 
-    template <typename... Args>
-    void PushMessageWithVersionAndFlag(CNode* pnode, int nVersion, int flag, const std::string& sCommand, Args&&... args)
-    {
-        auto msg(BeginMessage(pnode, nVersion, flag, sCommand));
-        ::SerializeMany(msg, std::forward<Args>(args)...);
-        EndMessage(msg);
-        PushMessage(pnode, msg, sCommand);
-    }
-
-    template <typename... Args>
-    void PushMessageWithFlag(CNode* pnode, int flag, const std::string& sCommand, Args&&... args)
-    {
-        PushMessageWithVersionAndFlag(pnode, 0, flag, sCommand, std::forward<Args>(args)...);
-    }
-
-    template <typename... Args>
-    void PushMessageWithVersion(CNode* pnode, int nVersion, const std::string& sCommand, Args&&... args)
-    {
-        PushMessageWithVersionAndFlag(pnode, nVersion, 0, sCommand, std::forward<Args>(args)...);
-    }
-
-    template <typename... Args>
-    void PushMessage(CNode* pnode, const std::string& sCommand, Args&&... args)
-    {
-        PushMessageWithVersionAndFlag(pnode, 0, 0, sCommand, std::forward<Args>(args)...);
-    }
+    void PushMessage(CNode* pnode, CSerializedNetMsg&& msg);
 
     template<typename Callable>
     bool ForEachNodeContinueIf(Callable&& func)
@@ -374,10 +363,6 @@ private:
 
     unsigned int GetReceiveFloodSize() const;
 
-    CDataStream BeginMessage(CNode* node, int nVersion, int flags, const std::string& sCommand);
-    void PushMessage(CNode* pnode, CDataStream& strm, const std::string& sCommand);
-    void EndMessage(CDataStream& strm);
-
     // Network stats
     void RecordBytesRecv(uint64_t bytes);
     void RecordBytesSent(uint64_t bytes);
@@ -601,7 +586,7 @@ public:
     size_t nSendSize; // total size of all vSendMsg entries
     size_t nSendOffset; // offset inside the first vSendMsg already sent
     uint64_t nSendBytes;
-    std::deque<CSerializeData> vSendMsg;
+    std::deque<std::vector<unsigned char>> vSendMsg;
     CCriticalSection cs_vSend;
 
     std::deque<CInv> vRecvGetData;
@@ -771,7 +756,7 @@ public:
     {
         // The send version should always be explicitly set to
         // INIT_PROTO_VERSION rather than using this value until the handshake
-        // is complete. See PushMessageWithVersion().
+        // is complete.
         assert(nSendVersion != 0);
         return nSendVersion;
     }
diff --git a/src/netmessagemaker.h b/src/netmessagemaker.h
new file mode 100644
index 0000000000..7167434a19
--- /dev/null
+++ b/src/netmessagemaker.h
@@ -0,0 +1,36 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2016 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_NETMESSAGEMAKER_H
+#define BITCOIN_NETMESSAGEMAKER_H
+
+#include "net.h"
+#include "serialize.h"
+
+class CNetMsgMaker
+{
+public:
+    CNetMsgMaker(int nVersionIn) : nVersion(nVersionIn){}
+
+    template <typename... Args>
+    CSerializedNetMsg Make(int nFlags, std::string sCommand, Args&&... args)
+    {
+        CSerializedNetMsg msg;
+        msg.command = std::move(sCommand);
+        CVectorWriter{ SER_NETWORK, nFlags | nVersion, msg.data, 0, std::forward<Args>(args)... };
+        return msg;
+    }
+
+    template <typename... Args>
+    CSerializedNetMsg Make(std::string sCommand, Args&&... args)
+    {
+        return Make(0, std::move(sCommand), std::forward<Args>(args)...);
+    }
+
+private:
+    const int nVersion;
+};
+
+#endif // BITCOIN_NETMESSAGEMAKER_H
diff --git a/src/qt/optionsmodel.h b/src/qt/optionsmodel.h
index b23b5f2607..d2e1fb23a3 100644
--- a/src/qt/optionsmodel.h
+++ b/src/qt/optionsmodel.h
@@ -81,7 +81,7 @@ private:
     int nDisplayUnit;
     QString strThirdPartyTxUrls;
     bool fCoinControlFeatures;
-    /* settings that were overriden by command-line */
+    /* settings that were overridden by command-line */
     QString strOverriddenByCommandLine;
 
     // Add option to list of GUI options overridden through command line/config file
diff --git a/src/rpc/mining.cpp b/src/rpc/mining.cpp
index 6b0e52a309..f3cd1fbf0b 100644
--- a/src/rpc/mining.cpp
+++ b/src/rpc/mining.cpp
@@ -680,7 +680,9 @@ UniValue getblocktemplate(const JSONRPCRequest& request)
     result.push_back(Pair("curtime", pblock->GetBlockTime()));
     result.push_back(Pair("bits", strprintf("%08x", pblock->nBits)));
     result.push_back(Pair("height", (int64_t)(pindexPrev->nHeight+1)));
-    if (!pblocktemplate->vchCoinbaseCommitment.empty()) {
+
+    const struct BIP9DeploymentInfo& segwit_info = VersionBitsDeploymentInfo[Consensus::DEPLOYMENT_SEGWIT];
+    if (!pblocktemplate->vchCoinbaseCommitment.empty() && setClientRules.find(segwit_info.name) != setClientRules.end()) {
         result.push_back(Pair("default_witness_commitment", HexStr(pblocktemplate->vchCoinbaseCommitment.begin(), pblocktemplate->vchCoinbaseCommitment.end())));
     }
 
diff --git a/src/streams.h b/src/streams.h
index c3e7c9e9e4..b508784238 100644
--- a/src/streams.h
+++ b/src/streams.h
@@ -69,6 +69,75 @@ OverrideStream<S> WithOrVersion(S* s, int nVersionFlag)
     return OverrideStream<S>(s, s->GetType(), s->GetVersion() | nVersionFlag);
 }
 
+/* Minimal stream for overwriting and/or appending to an existing byte vector
+ *
+ * The referenced vector will grow as necessary
+ */
+class CVectorWriter
+{
+ public:
+
+/*
+ * @param[in]  nTypeIn Serialization Type
+ * @param[in]  nVersionIn Serialization Version (including any flags)
+ * @param[in]  vchDataIn  Referenced byte vector to overwrite/append
+ * @param[in]  nPosIn Starting position. Vector index where writes should start. The vector will initially
+ *                    grow as necessary to  max(index, vec.size()). So to append, use vec.size().
+*/
+    CVectorWriter(int nTypeIn, int nVersionIn, std::vector<unsigned char>& vchDataIn, size_t nPosIn) : nType(nTypeIn), nVersion(nVersionIn), vchData(vchDataIn), nPos(nPosIn)
+    {
+        if(nPos > vchData.size())
+            vchData.resize(nPos);
+    }
+/*
+ * (other params same as above)
+ * @param[in]  args  A list of items to serialize starting at nPos.
+*/
+    template <typename... Args>
+    CVectorWriter(int nTypeIn, int nVersionIn, std::vector<unsigned char>& vchDataIn, size_t nPosIn, Args&&... args) : CVectorWriter(nTypeIn, nVersionIn, vchDataIn, nPosIn)
+    {
+        ::SerializeMany(*this, std::forward<Args>(args)...);
+    }
+    void write(const char* pch, size_t nSize)
+    {
+        assert(nPos <= vchData.size());
+        size_t nOverwrite = std::min(nSize, vchData.size() - nPos);
+        if (nOverwrite) {
+            memcpy(vchData.data() + nPos, reinterpret_cast<const unsigned char*>(pch), nOverwrite);
+        }
+        if (nOverwrite < nSize) {
+            vchData.insert(vchData.end(), reinterpret_cast<const unsigned char*>(pch) + nOverwrite, reinterpret_cast<const unsigned char*>(pch) + nSize);
+        }
+        nPos += nSize;
+    }
+    template<typename T>
+    CVectorWriter& operator<<(const T& obj)
+    {
+        // Serialize to this stream
+        ::Serialize(*this, obj);
+        return (*this);
+    }
+    int GetVersion() const
+    {
+        return nVersion;
+    }
+    int GetType() const
+    {
+        return nType;
+    }
+    void seek(size_t nSize)
+    {
+        nPos += nSize;
+        if(nPos > vchData.size())
+            vchData.resize(nPos);
+    }
+private:
+    const int nType;
+    const int nVersion;
+    std::vector<unsigned char>& vchData;
+    size_t nPos;
+};
+
 /** Double ended buffer combining vector and stream-like interfaces.
  *
  * >> and << read and write unformatted data using the above serialization templates.
diff --git a/src/support/lockedpool.h b/src/support/lockedpool.h
index 3403415436..f5212bc266 100644
--- a/src/support/lockedpool.h
+++ b/src/support/lockedpool.h
@@ -109,7 +109,7 @@ private:
  * An arena manages a contiguous region of memory. The pool starts out with one arena
  * but can grow to multiple arenas if the need arises.
  *
- * Unlike a normal C heap, the administrative structures are seperate from the managed
+ * Unlike a normal C heap, the administrative structures are separate from the managed
  * memory. This has been done as the sizes and bases of objects are not in themselves sensitive
  * information, as to conserve precious locked memory. In some operating systems
  * the amount of memory that can be locked is small.
diff --git a/src/test/bitcoin-util-test.py b/src/test/bitcoin-util-test.py
index 4301b93b7c..1c090b3f3f 100755
--- a/src/test/bitcoin-util-test.py
+++ b/src/test/bitcoin-util-test.py
@@ -15,7 +15,7 @@ help_text="""Test framework for bitcoin utils.
 
 Runs automatically during `make check`.
 
-Can also be run manually from the src directory by specifiying the source directory:
+Can also be run manually from the src directory by specifying the source directory:
 
 test/bitcoin-util-test.py --srcdir='srcdir' [--verbose]
 """
diff --git a/src/test/data/tx_valid.json b/src/test/data/tx_valid.json
index 2f299aa5fe..27acb2f16a 100644
--- a/src/test/data/tx_valid.json
+++ b/src/test/data/tx_valid.json
@@ -53,7 +53,7 @@
 ["The following tests for the presence of a bug in the handling of SIGHASH_SINGLE"],
 ["It results in signing the constant 1, instead of something generated based on the transaction,"],
 ["when the input doing the signing has an index greater than the maximum output index"],
-[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "DUP HASH160 0x14 0xe52b482f2faa8ecbf0db344f93c84ac908557f33 EQUALVERIFY CHECKSIG"], ["0000000000000000000000000000000000000000000000000000000000000200", 0, "1"]],
+[[["0000000000000000000000000000000000000000000000000000000000000200", 0, "1"], ["0000000000000000000000000000000000000000000000000000000000000100", 0, "DUP HASH160 0x14 0xe52b482f2faa8ecbf0db344f93c84ac908557f33 EQUALVERIFY CHECKSIG"]],
 "01000000020002000000000000000000000000000000000000000000000000000000000000000000000151ffffffff0001000000000000000000000000000000000000000000000000000000000000000000006b483045022100c9cdd08798a28af9d1baf44a6c77bcc7e279f47dc487c8c899911bc48feaffcc0220503c5c50ae3998a733263c5c0f7061b483e2b56c4c41b456e7d2f5a78a74c077032102d5c25adb51b61339d2b05315791e21bbe80ea470a49db0135720983c905aace0ffffffff010000000000000000015100000000", "P2SH"],
 
 ["An invalid P2SH Transaction"],
@@ -334,9 +334,9 @@
 "0100000000010100010000000000000000000000000000000000000000000000000000000000000000000023220020ff25429251b5a84f452230a3c75fd886b7fc5a7865ce4a7bb7a9d7c5be6da3dbffffffff01e8030000000000001976a9144c9c3dfac4207d5d8cb89df5722cb3d712385e3f88ac02483045022100aa5d8aa40a90f23ce2c3d11bc845ca4a12acd99cbea37de6b9f6d86edebba8cb022022dedc2aa0a255f74d04c0b76ece2d7c691f9dd11a64a8ac49f62a99c3a05f9d01232103596d3451025c19dbbdeb932d6bf8bfb4ad499b95b6f88db8899efac102e5fc71ac00000000", "P2SH,WITNESS"],
 
 ["Witness with SigHash Single|AnyoneCanPay"],
-[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "0x51", 1100],
+[[["0000000000000000000000000000000000000000000000000000000000000100", 2, "0x51", 3100],
 ["0000000000000000000000000000000000000000000000000000000000000100", 1, "0x00 0x14 0x4c9c3dfac4207d5d8cb89df5722cb3d712385e3f", 2000],
-["0000000000000000000000000000000000000000000000000000000000000100", 2, "0x51", 3100],
+["0000000000000000000000000000000000000000000000000000000000000100", 0, "0x51", 1100],
 ["0000000000000000000000000000000000000000000000000000000000000100", 3, "0x51", 4100]],
 "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", "P2SH,WITNESS"],
 
@@ -359,9 +359,9 @@
 "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", "P2SH,WITNESS"],
 
 ["Witness with SigHash None|AnyoneCanPay"],
-[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "0x51", 1100],
+[[["0000000000000000000000000000000000000000000000000000000000000100", 2, "0x51", 3100],
+["0000000000000000000000000000000000000000000000000000000000000100", 0, "0x51", 1100],
 ["0000000000000000000000000000000000000000000000000000000000000100", 1, "0x00 0x14 0x4c9c3dfac4207d5d8cb89df5722cb3d712385e3f", 2000],
-["0000000000000000000000000000000000000000000000000000000000000100", 2, "0x51", 3100],
 ["0000000000000000000000000000000000000000000000000000000000000100", 3, "0x51", 4100]],
 "0100000000010400010000000000000000000000000000000000000000000000000000000000000200000000ffffffff00010000000000000000000000000000000000000000000000000000000000000000000000ffffffff00010000000000000000000000000000000000000000000000000000000000000100000000ffffffff00010000000000000000000000000000000000000000000000000000000000000300000000ffffffff04b60300000000000001519e070000000000000151860b00000000000001009600000000000000015100000248304502210091b32274295c2a3fa02f5bce92fb2789e3fc6ea947fbe1a76e52ea3f4ef2381a022079ad72aefa3837a2e0c033a8652a59731da05fa4a813f4fc48e87c075037256b822103596d3451025c19dbbdeb932d6bf8bfb4ad499b95b6f88db8899efac102e5fc710000000000", "P2SH,WITNESS"],
 
@@ -390,9 +390,9 @@
 "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", "P2SH,WITNESS"],
 
 ["Witness with SigHash All|AnyoneCanPay"],
-[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "0x51", 1100],
+[[["0000000000000000000000000000000000000000000000000000000000000100", 2, "0x51", 3100],
+["0000000000000000000000000000000000000000000000000000000000000100", 0, "0x51", 1100],
 ["0000000000000000000000000000000000000000000000000000000000000100", 1, "0x00 0x14 0x4c9c3dfac4207d5d8cb89df5722cb3d712385e3f", 2000],
-["0000000000000000000000000000000000000000000000000000000000000100", 2, "0x51", 3100],
 ["0000000000000000000000000000000000000000000000000000000000000100", 3, "0x51", 4100]],
 "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", "P2SH,WITNESS"],
 
@@ -458,8 +458,8 @@
 "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", "P2SH,WITNESS"],
 
 ["Witness Single|AnyoneCanPay does not hash input's position (permutation)"],
-[[["0000000000000000000000000000000000000000000000000000000000000100", 0, "0x00 0x14 0x4c9c3dfac4207d5d8cb89df5722cb3d712385e3f", 1000],
-["0000000000000000000000000000000000000000000000000000000000000100", 1, "0x00 0x14 0x4c9c3dfac4207d5d8cb89df5722cb3d712385e3f", 1001]],
+[[["0000000000000000000000000000000000000000000000000000000000000100", 1, "0x00 0x14 0x4c9c3dfac4207d5d8cb89df5722cb3d712385e3f", 1001],
+["0000000000000000000000000000000000000000000000000000000000000100", 0, "0x00 0x14 0x4c9c3dfac4207d5d8cb89df5722cb3d712385e3f", 1000]],
 "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", "P2SH,WITNESS"],
 
 ["Non witness Single|AnyoneCanPay hash input's position"],
diff --git a/src/test/limitedmap_tests.cpp b/src/test/limitedmap_tests.cpp
index faaddffad8..e3531486aa 100644
--- a/src/test/limitedmap_tests.cpp
+++ b/src/test/limitedmap_tests.cpp
@@ -47,7 +47,7 @@ BOOST_AUTO_TEST_CASE(limitedmap_test)
         // make sure the item is present
         BOOST_CHECK(map.count(i) == 1);
 
-        // use the iterator to check for the expected key adn value
+        // use the iterator to check for the expected key and value
         BOOST_CHECK(it->first == i);
         BOOST_CHECK(it->second == i + 1);
         
diff --git a/src/test/miner_tests.cpp b/src/test/miner_tests.cpp
index aea8920936..85a2e907c2 100644
--- a/src/test/miner_tests.cpp
+++ b/src/test/miner_tests.cpp
@@ -214,6 +214,7 @@ BOOST_AUTO_TEST_CASE(CreateNewBlock_validity)
         txCoinbase.vin[0].scriptSig = CScript();
         txCoinbase.vin[0].scriptSig.push_back(blockinfo[i].extranonce);
         txCoinbase.vin[0].scriptSig.push_back(chainActive.Height());
+        txCoinbase.vout.resize(1); // Ignore the (optional) segwit commitment added by CreateNewBlock (as the hardcoded nonces don't account for this)
         txCoinbase.vout[0].scriptPubKey = CScript();
         pblock->vtx[0] = MakeTransactionRef(std::move(txCoinbase));
         if (txFirst.size() == 0)
diff --git a/src/test/streams_tests.cpp b/src/test/streams_tests.cpp
index 34f501e867..8b715ce93e 100644
--- a/src/test/streams_tests.cpp
+++ b/src/test/streams_tests.cpp
@@ -15,6 +15,64 @@ using namespace boost::assign; // bring 'operator+=()' into scope
 
 BOOST_FIXTURE_TEST_SUITE(streams_tests, BasicTestingSetup)
 
+BOOST_AUTO_TEST_CASE(streams_vector_writer)
+{
+    unsigned char a(1);
+    unsigned char b(2);
+    unsigned char bytes[] = { 3, 4, 5, 6 };
+    std::vector<unsigned char> vch;
+
+    // Each test runs twice. Serializing a second time at the same starting
+    // point should yield the same results, even if the first test grew the
+    // vector.
+
+    CVectorWriter(SER_NETWORK, INIT_PROTO_VERSION, vch, 0, a, b);
+    BOOST_CHECK((vch == std::vector<unsigned char>{{1, 2}}));
+    CVectorWriter(SER_NETWORK, INIT_PROTO_VERSION, vch, 0, a, b);
+    BOOST_CHECK((vch == std::vector<unsigned char>{{1, 2}}));
+    vch.clear();
+
+    CVectorWriter(SER_NETWORK, INIT_PROTO_VERSION, vch, 2, a, b);
+    BOOST_CHECK((vch == std::vector<unsigned char>{{0, 0, 1, 2}}));
+    CVectorWriter(SER_NETWORK, INIT_PROTO_VERSION, vch, 2, a, b);
+    BOOST_CHECK((vch == std::vector<unsigned char>{{0, 0, 1, 2}}));
+    vch.clear();
+
+    vch.resize(5, 0);
+    CVectorWriter(SER_NETWORK, INIT_PROTO_VERSION, vch, 2, a, b);
+    BOOST_CHECK((vch == std::vector<unsigned char>{{0, 0, 1, 2, 0}}));
+    CVectorWriter(SER_NETWORK, INIT_PROTO_VERSION, vch, 2, a, b);
+    BOOST_CHECK((vch == std::vector<unsigned char>{{0, 0, 1, 2, 0}}));
+    vch.clear();
+
+    vch.resize(4, 0);
+    CVectorWriter(SER_NETWORK, INIT_PROTO_VERSION, vch, 3, a, b);
+    BOOST_CHECK((vch == std::vector<unsigned char>{{0, 0, 0, 1, 2}}));
+    CVectorWriter(SER_NETWORK, INIT_PROTO_VERSION, vch, 3, a, b);
+    BOOST_CHECK((vch == std::vector<unsigned char>{{0, 0, 0, 1, 2}}));
+    vch.clear();
+
+    vch.resize(4, 0);
+    CVectorWriter(SER_NETWORK, INIT_PROTO_VERSION, vch, 4, a, b);
+    BOOST_CHECK((vch == std::vector<unsigned char>{{0, 0, 0, 0, 1, 2}}));
+    CVectorWriter(SER_NETWORK, INIT_PROTO_VERSION, vch, 4, a, b);
+    BOOST_CHECK((vch == std::vector<unsigned char>{{0, 0, 0, 0, 1, 2}}));
+    vch.clear();
+
+    CVectorWriter(SER_NETWORK, INIT_PROTO_VERSION, vch, 0, FLATDATA(bytes));
+    BOOST_CHECK((vch == std::vector<unsigned char>{{3, 4, 5, 6}}));
+    CVectorWriter(SER_NETWORK, INIT_PROTO_VERSION, vch, 0, FLATDATA(bytes));
+    BOOST_CHECK((vch == std::vector<unsigned char>{{3, 4, 5, 6}}));
+    vch.clear();
+
+    vch.resize(4, 8);
+    CVectorWriter(SER_NETWORK, INIT_PROTO_VERSION, vch, 2, a, FLATDATA(bytes), b);
+    BOOST_CHECK((vch == std::vector<unsigned char>{{8, 8, 1, 3, 4, 5, 6, 2}}));
+    CVectorWriter(SER_NETWORK, INIT_PROTO_VERSION, vch, 2, a, FLATDATA(bytes), b);
+    BOOST_CHECK((vch == std::vector<unsigned char>{{8, 8, 1, 3, 4, 5, 6, 2}}));
+    vch.clear();
+}
+
 BOOST_AUTO_TEST_CASE(streams_serializedata_xor)
 {
     std::vector<char> in;
diff --git a/src/txmempool.h b/src/txmempool.h
index 29b59363a2..23fe5a7abe 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -62,7 +62,7 @@ class CTxMemPool;
 
 /** \class CTxMemPoolEntry
  *
- * CTxMemPoolEntry stores data about the correponding transaction, as well
+ * CTxMemPoolEntry stores data about the corresponding transaction, as well
  * as data about all in-mempool transactions that depend on the transaction
  * ("descendant" transactions).
  *