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Merge #16202: p2p: Refactor network message deserialization

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ed2dc5e48a Add override/final modifiers to V1TransportDeserializer (Pieter Wuille)
f342a5e61a Make resetting implicit in TransportDeserializer::Read() (Pieter Wuille)
6a91499496 Remove oversized message detection from log and interface (Pieter Wuille)
b0e10ff4df Force CNetMessage::m_recv to use std::move (Jonas Schnelli)
efecb74677 Use adapter pattern for the network deserializer (Jonas Schnelli)
1a5c656c31 Remove transport protocol knowhow from CNetMessage / net processing (Jonas Schnelli)
6294ecdb8b Refactor: split network transport deserializing from message container (Jonas Schnelli)

Pull request description:

  **This refactors the network message deserialization.**

  * It transforms the `CNetMessage` into a transport protocol agnostic message container.
  * A new class `TransportDeserializer` (unique pointer of `CNode`)  is introduced, handling the network buffer reading and the decomposing to a `CNetMessage`
  * **No behavioral changes** (in terms of disconnecting, punishing)
  * Moves the checksum finalizing into the `SocketHandler` thread (finalizing was in `ProcessMessages` before)

  The **optional last commit** makes the `TransportDeserializer` following an adapter pattern (polymorphic interface) to make it easier to later add a V2 transport protocol deserializer.

  Intentionally not touching the sending part.

  Pre-Requirement for BIP324 (v2 message transport protocol).
  Replacement for #14046 and inspired by a [comment](https://github.com/bitcoin/bitcoin/pull/14046#issuecomment-431528330) from sipa

ACKs for top commit:
  promag:
    Code review ACK ed2dc5e48a.
  marcinja:
    Code review ACK ed2dc5e48a
  ryanofsky:
    Code review ACK ed2dc5e48a. 4 cleanup commits added since last review. Unaddressed comments:
  ariard:
    Code review and tested ACK ed2dc5e.

Tree-SHA512: bab8d87464e2e8742529e488ddcdc8650f0c2025c9130913df00a0b17ecdb9a525061cbbbd0de0251b76bf75a8edb72e3ad0dbf5b79e26f2ad05d61b4e4ded6d
This commit is contained in:
fanquake
2019-10-28 09:15:48 -04:00
parent f8cc2b967b ed2dc5e48a
commit badca85e2c
4 changed files with 138 additions and 76 deletions
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88
src/net.cpp
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@@ -567,42 +567,28 @@ bool CNode::ReceiveMsgBytes(const char *pch, unsigned int nBytes, bool& complete
nLastRecv = nTimeMicros / 1000000;
nRecvBytes += nBytes;
while (nBytes > 0) {
// get current incomplete message, or create a new one
if (vRecvMsg.empty() ||
vRecvMsg.back().complete())
vRecvMsg.push_back(CNetMessage(Params().MessageStart(), SER_NETWORK, INIT_PROTO_VERSION));
CNetMessage& msg = vRecvMsg.back();
// absorb network data
int handled;
if (!msg.in_data)
handled = msg.readHeader(pch, nBytes);
else
handled = msg.readData(pch, nBytes);
if (handled < 0)
return false;
if (msg.in_data && msg.hdr.nMessageSize > MAX_PROTOCOL_MESSAGE_LENGTH) {
LogPrint(BCLog::NET, "Oversized message from peer=%i, disconnecting\n", GetId());
return false;
}
int handled = m_deserializer->Read(pch, nBytes);
if (handled < 0) return false;
pch += handled;
nBytes -= handled;
if (msg.complete()) {
if (m_deserializer->Complete()) {
// decompose a transport agnostic CNetMessage from the deserializer
CNetMessage msg = m_deserializer->GetMessage(Params().MessageStart(), nTimeMicros);
//store received bytes per message command
//to prevent a memory DOS, only allow valid commands
mapMsgCmdSize::iterator i = mapRecvBytesPerMsgCmd.find(msg.hdr.pchCommand);
mapMsgCmdSize::iterator i = mapRecvBytesPerMsgCmd.find(msg.m_command);
if (i == mapRecvBytesPerMsgCmd.end())
i = mapRecvBytesPerMsgCmd.find(NET_MESSAGE_COMMAND_OTHER);
assert(i != mapRecvBytesPerMsgCmd.end());
i->second += msg.hdr.nMessageSize + CMessageHeader::HEADER_SIZE;
i->second += msg.m_raw_message_size;
// push the message to the process queue,
vRecvMsg.push_back(std::move(msg));
msg.nTime = nTimeMicros;
complete = true;
}
}
@@ -636,8 +622,7 @@ int CNode::GetSendVersion() const
return nSendVersion;
}
int CNetMessage::readHeader(const char *pch, unsigned int nBytes)
int V1TransportDeserializer::readHeader(const char *pch, unsigned int nBytes)
{
// copy data to temporary parsing buffer
unsigned int nRemaining = 24 - nHdrPos;
@@ -658,9 +643,10 @@ int CNetMessage::readHeader(const char *pch, unsigned int nBytes)
return -1;
}
// reject messages larger than MAX_SIZE
if (hdr.nMessageSize > MAX_SIZE)
// reject messages larger than MAX_SIZE or MAX_PROTOCOL_MESSAGE_LENGTH
if (hdr.nMessageSize > MAX_SIZE || hdr.nMessageSize > MAX_PROTOCOL_MESSAGE_LENGTH) {
return -1;
}
// switch state to reading message data
in_data = true;
@@ -668,7 +654,7 @@ int CNetMessage::readHeader(const char *pch, unsigned int nBytes)
return nCopy;
}
int CNetMessage::readData(const char *pch, unsigned int nBytes)
int V1TransportDeserializer::readData(const char *pch, unsigned int nBytes)
{
unsigned int nRemaining = hdr.nMessageSize - nDataPos;
unsigned int nCopy = std::min(nRemaining, nBytes);
@@ -685,14 +671,44 @@ int CNetMessage::readData(const char *pch, unsigned int nBytes)
return nCopy;
}
const uint256& CNetMessage::GetMessageHash() const
const uint256& V1TransportDeserializer::GetMessageHash() const
{
assert(complete());
assert(Complete());
if (data_hash.IsNull())
hasher.Finalize(data_hash.begin());
return data_hash;
}
CNetMessage V1TransportDeserializer::GetMessage(const CMessageHeader::MessageStartChars& message_start, int64_t time) {
// decompose a single CNetMessage from the TransportDeserializer
CNetMessage msg(std::move(vRecv));
// store state about valid header, netmagic and checksum
msg.m_valid_header = hdr.IsValid(message_start);
msg.m_valid_netmagic = (memcmp(hdr.pchMessageStart, message_start, CMessageHeader::MESSAGE_START_SIZE) == 0);
uint256 hash = GetMessageHash();
// store command string, payload size
msg.m_command = hdr.GetCommand();
msg.m_message_size = hdr.nMessageSize;
msg.m_raw_message_size = hdr.nMessageSize + CMessageHeader::HEADER_SIZE;
msg.m_valid_checksum = (memcmp(hash.begin(), hdr.pchChecksum, CMessageHeader::CHECKSUM_SIZE) == 0);
if (!msg.m_valid_checksum) {
LogPrint(BCLog::NET, "CHECKSUM ERROR (%s, %u bytes), expected %s was %s\n",
SanitizeString(msg.m_command), msg.m_message_size,
HexStr(hash.begin(), hash.begin()+CMessageHeader::CHECKSUM_SIZE),
HexStr(hdr.pchChecksum, hdr.pchChecksum+CMessageHeader::CHECKSUM_SIZE));
}
// store receive time
msg.m_time = time;
// reset the network deserializer (prepare for the next message)
Reset();
return msg;
}
size_t CConnman::SocketSendData(CNode *pnode) const EXCLUSIVE_LOCKS_REQUIRED(pnode->cs_vSend)
{
auto it = pnode->vSendMsg.begin();
@@ -1344,9 +1360,9 @@ void CConnman::SocketHandler()
size_t nSizeAdded = 0;
auto it(pnode->vRecvMsg.begin());
for (; it != pnode->vRecvMsg.end(); ++it) {
if (!it->complete())
break;
nSizeAdded += it->vRecv.size() + CMessageHeader::HEADER_SIZE;
// vRecvMsg contains only completed CNetMessage
// the single possible partially deserialized message are held by TransportDeserializer
nSizeAdded += it->m_raw_message_size;
}
{
LOCK(pnode->cs_vProcessMsg);
@@ -2676,6 +2692,8 @@ CNode::CNode(NodeId idIn, ServiceFlags nLocalServicesIn, int nMyStartingHeightIn
} else {
LogPrint(BCLog::NET, "Added connection peer=%d\n", id);
}
m_deserializer = MakeUnique<V1TransportDeserializer>(V1TransportDeserializer(Params().MessageStart(), SER_NETWORK, INIT_PROTO_VERSION));
}
CNode::~CNode()