From c7be56dceff625991cb2884f2ce053996ac613cd Mon Sep 17 00:00:00 2001
From: Cory Fields <cory-nospam-@coryfields.com>
Date: Thu, 10 Nov 2016 20:17:30 -0500
Subject: net: push only raw data into CConnman

This fixes one of the last major layer violations in the networking stack.

The network side is no longer in charge of message serialization, so it is now
decoupled from Bitcoin structures. Only the header is serialized and attached
to the payload.
---
 src/net.cpp | 46 +++++++++++++++++++---------------------------
 1 file changed, 19 insertions(+), 27 deletions(-)

(limited to 'src/net.cpp')

diff --git a/src/net.cpp b/src/net.cpp
index 15c4514f1..ce87150ae 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;
@@ -2612,30 +2612,19 @@ 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;
     {
@@ -2644,11 +2633,14 @@ 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)
-- 
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