Merge bitcoin/bitcoin#26359: p2p: Erlay support signaling follow-ups

46339d2 test, refactor: Reorder sendtxrcncl tests for better readability (Gleb Naumenko)
14263c1 p2p, refactor: Extend logs for unexpected sendtxrcncl (Gleb Naumenko)
87493e1 p2p, test, refactor: Minor code improvements (Gleb Naumenko)
00c5dec p2p: Clarify sendtxrcncl policies (Gleb Naumenko)
ac6ee5b test: Expand unit and functional tests for txreconciliation (Gleb Naumenko)
bc84e24 p2p, refactor: Switch to enum class for ReconciliationRegisterResult (Gleb Naumenko)
a60f729 p2p: Drop roles from sendtxrcncl (Gleb Naumenko)
6772cbf tests: stabilize sendtxrcncl test (Gleb Naumenko)

Pull request description:

  Non-trivial changes include:
  - Getting rid of roles in `sendtxrcncl` message (summarized in the [BIP PR](bitcoin/bips#1376));
  - Disconnect the peer if it send `sendtxrcncl` although we are in `blocksonly` and notified the peer with `fRelay=0`;
  - Don't send `sendtxrcncl` to feeler connections.

ACKs for top commit:
  vasild:
    ACK 46339d2
  ariard:
    ACK 46339d2
  mzumsande:
    Code Review ACK 46339d2

Tree-SHA512: b5cc6934b4670c12b7dbb3189e739ef747ee542ec56678bf4e4355bfb481b746d32363c173635685b71969b3fe4bd52b1c8ebd3ea3b35c82044bba69220f6417

Author: fanquake

src/init.cpp

@@ -477,6 +477,7 @@ void SetupServerArgs(ArgsManager& argsman)
     argsman.AddArg("-onlynet=<net>", "Make automatic outbound connections only to network <net> (" + Join(GetNetworkNames(), ", ") + "). Inbound and manual connections are not affected by this option. It can be specified multiple times to allow multiple networks.", ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-peerbloomfilters", strprintf("Support filtering of blocks and transaction with bloom filters (default: %u)", DEFAULT_PEERBLOOMFILTERS), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-peerblockfilters", strprintf("Serve compact block filters to peers per BIP 157 (default: %u)", DEFAULT_PEERBLOCKFILTERS), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
+    argsman.AddArg("-txreconciliation", strprintf("Enable transaction reconciliations per BIP 330 (default: %d)", DEFAULT_TXRECONCILIATION_ENABLE), ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::CONNECTION);
     // TODO: remove the sentence "Nodes not using ... incoming connections." once the changes from
     // https://github.com/bitcoin/bitcoin/pull/23542 have become widespread.
     argsman.AddArg("-port=<port>", strprintf("Listen for connections on <port>. Nodes not using the default ports (default: %u, testnet: %u, signet: %u, regtest: %u) are unlikely to get incoming connections. Not relevant for I2P (see doc/i2p.md).", defaultChainParams->GetDefaultPort(), testnetChainParams->GetDefaultPort(), signetChainParams->GetDefaultPort(), regtestChainParams->GetDefaultPort()), ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY, OptionsCategory::CONNECTION);
@@ -485,7 +486,6 @@ void SetupServerArgs(ArgsManager& argsman)
     argsman.AddArg("-seednode=<ip>", "Connect to a node to retrieve peer addresses, and disconnect. This option can be specified multiple times to connect to multiple nodes.", ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-networkactive", "Enable all P2P network activity (default: 1). Can be changed by the setnetworkactive RPC command", ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-timeout=<n>", strprintf("Specify socket connection timeout in milliseconds. If an initial attempt to connect is unsuccessful after this amount of time, drop it (minimum: 1, default: %d)", DEFAULT_CONNECT_TIMEOUT), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
-    argsman.AddArg("-txreconciliation", strprintf("Enable transaction reconciliations per BIP 330 (default: %d)", DEFAULT_TXRECONCILIATION_ENABLE), ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::CONNECTION);
     argsman.AddArg("-peertimeout=<n>", strprintf("Specify a p2p connection timeout delay in seconds. After connecting to a peer, wait this amount of time before considering disconnection based on inactivity (minimum: 1, default: %d)", DEFAULT_PEER_CONNECT_TIMEOUT), ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::CONNECTION);
     argsman.AddArg("-torcontrol=<ip>:<port>", strprintf("Tor control port to use if onion listening enabled (default: %s)", DEFAULT_TOR_CONTROL), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     argsman.AddArg("-torpassword=<pass>", "Tor control port password (default: empty)", ArgsManager::ALLOW_ANY | ArgsManager::SENSITIVE, OptionsCategory::CONNECTION);

src/net_processing.cpp

@@ -3273,17 +3273,14 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
 
         if (greatest_common_version >= WTXID_RELAY_VERSION && m_txreconciliation) {
             // Per BIP-330, we announce txreconciliation support if:
-            // - protocol version per the VERSION message supports WTXID_RELAY;
-            // - we intended to exchange transactions over this connection while establishing it
-            //   and the peer indicated support for transaction relay in the VERSION message;
+            // - protocol version per the peer's VERSION message supports WTXID_RELAY;
+            // - transaction relay is supported per the peer's VERSION message (see m_relays_txs);
+            // - this is not a block-relay-only connection and not a feeler (see m_relays_txs);
+            // - this is not an addr fetch connection;
             // - we are not in -blocksonly mode.
-            if (pfrom.m_relays_txs && !m_ignore_incoming_txs) {
+            if (pfrom.m_relays_txs && !pfrom.IsAddrFetchConn() && !m_ignore_incoming_txs) {
                 const uint64_t recon_salt = m_txreconciliation->PreRegisterPeer(pfrom.GetId());
-                // We suggest our txreconciliation role (initiator/responder) based on
-                // the connection direction.
                 m_connman.PushMessage(&pfrom, msg_maker.Make(NetMsgType::SENDTXRCNCL,
-                                                             !pfrom.IsInboundConn(),
-                                                             pfrom.IsInboundConn(),
                                                              TXRECONCILIATION_VERSION, recon_salt));
             }
         }
@@ -3500,41 +3497,44 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
         }
 
         if (pfrom.fSuccessfullyConnected) {
-            // Disconnect peers that send a SENDTXRCNCL message after VERACK.
             LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "sendtxrcncl received after verack from peer=%d; disconnecting\n", pfrom.GetId());
             pfrom.fDisconnect = true;
             return;
         }
 
-        if (!peer->GetTxRelay()) {
-            // Disconnect peers that send a SENDTXRCNCL message even though we indicated we don't
-            // support transaction relay.
+        // Peer must not offer us reconciliations if we specified no tx relay support in VERSION.
+        if (RejectIncomingTxs(pfrom)) {
             LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "sendtxrcncl received from peer=%d to which we indicated no tx relay; disconnecting\n", pfrom.GetId());
             pfrom.fDisconnect = true;
             return;
         }
 
-        bool is_peer_initiator, is_peer_responder;
+        // Peer must not offer us reconciliations if they specified no tx relay support in VERSION.
+        // This flag might also be false in other cases, but the RejectIncomingTxs check above
+        // eliminates them, so that this flag fully represents what we are looking for.
+        if (!pfrom.m_relays_txs) {
+            LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "sendtxrcncl received from peer=%d which indicated no tx relay to us; disconnecting\n", pfrom.GetId());
+            pfrom.fDisconnect = true;
+            return;
+        }
+
         uint32_t peer_txreconcl_version;
         uint64_t remote_salt;
-        vRecv >> is_peer_initiator >> is_peer_responder >> peer_txreconcl_version >> remote_salt;
+        vRecv >> peer_txreconcl_version >> remote_salt;
 
-        if (m_txreconciliation->IsPeerRegistered(pfrom.GetId())) {
-            // A peer is already registered, meaning we already received SENDTXRCNCL from them.
+        const ReconciliationRegisterResult result = m_txreconciliation->RegisterPeer(pfrom.GetId(), pfrom.IsInboundConn(),
+                                                                                     peer_txreconcl_version, remote_salt);
+        switch (result) {
+        case ReconciliationRegisterResult::NOT_FOUND:
+            LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "Ignore unexpected txreconciliation signal from peer=%d\n", pfrom.GetId());
+            break;
+        case ReconciliationRegisterResult::SUCCESS:
+            break;
+        case ReconciliationRegisterResult::ALREADY_REGISTERED:
             LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "txreconciliation protocol violation from peer=%d (sendtxrcncl received from already registered peer); disconnecting\n", pfrom.GetId());
             pfrom.fDisconnect = true;
             return;
-        }
-
-        const ReconciliationRegisterResult result = m_txreconciliation->RegisterPeer(pfrom.GetId(), pfrom.IsInboundConn(),
-                                                                                is_peer_initiator, is_peer_responder,
-                                                                                peer_txreconcl_version,
-                                                                                remote_salt);
-
-        // If it's a protocol violation, disconnect.
-        // If the peer was not found (but something unexpected happened) or it was registered,
-        // nothing to be done.
-        if (result == ReconciliationRegisterResult::PROTOCOL_VIOLATION) {
+        case ReconciliationRegisterResult::PROTOCOL_VIOLATION:
             LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "txreconciliation protocol violation from peer=%d; disconnecting\n", pfrom.GetId());
             pfrom.fDisconnect = true;
             return;

src/node/txreconciliation.cpp

@@ -39,7 +39,8 @@ class TxReconciliationState
      * the following commits.
      *
      * Reconciliation protocol assumes using one role consistently: either a reconciliation
-     * initiator (requesting sketches), or responder (sending sketches). This defines our role.
+     * initiator (requesting sketches), or responder (sending sketches). This defines our role,
+     * based on the direction of the p2p connection.
      *
      */
     bool m_we_initiate;
@@ -81,31 +82,30 @@ class TxReconciliationTracker::Impl
     {
         AssertLockNotHeld(m_txreconciliation_mutex);
         LOCK(m_txreconciliation_mutex);
-        // We do not support txreconciliation salt/version updates.
-        assert(m_states.find(peer_id) == m_states.end());
 
         LogPrintLevel(BCLog::TXRECONCILIATION, BCLog::Level::Debug, "Pre-register peer=%d\n", peer_id);
         const uint64_t local_salt{GetRand(UINT64_MAX)};
 
         // We do this exactly once per peer (which are unique by NodeId, see GetNewNodeId) so it's
         // safe to assume we don't have this record yet.
-        Assert(m_states.emplace(peer_id, local_salt).second);
+        Assume(m_states.emplace(peer_id, local_salt).second);
         return local_salt;
     }
 
-    ReconciliationRegisterResult RegisterPeer(NodeId peer_id, bool is_peer_inbound, bool is_peer_recon_initiator,
-                                     bool is_peer_recon_responder, uint32_t peer_recon_version,
-                                     uint64_t remote_salt) EXCLUSIVE_LOCKS_REQUIRED(!m_txreconciliation_mutex)
+    ReconciliationRegisterResult RegisterPeer(NodeId peer_id, bool is_peer_inbound, uint32_t peer_recon_version,
+                                              uint64_t remote_salt) EXCLUSIVE_LOCKS_REQUIRED(!m_txreconciliation_mutex)
     {
         AssertLockNotHeld(m_txreconciliation_mutex);
         LOCK(m_txreconciliation_mutex);
         auto recon_state = m_states.find(peer_id);
 
-        // A peer should be in the pre-registered state to proceed here.
-        if (recon_state == m_states.end()) return NOT_FOUND;
-        uint64_t* local_salt = std::get_if<uint64_t>(&recon_state->second);
-        // A peer is already registered. This should be checked by the caller.
-        Assume(local_salt);
+        if (recon_state == m_states.end()) return ReconciliationRegisterResult::NOT_FOUND;
+
+        if (std::holds_alternative<TxReconciliationState>(recon_state->second)) {
+            return ReconciliationRegisterResult::ALREADY_REGISTERED;
+        }
+
+        uint64_t local_salt = *std::get_if<uint64_t>(&recon_state->second);
 
         // If the peer supports the version which is lower than ours, we downgrade to the version
         // it supports. For now, this only guarantees that nodes with future reconciliation
@@ -114,27 +114,14 @@ class TxReconciliationTracker::Impl
         // satisfactory (e.g. too low).
         const uint32_t recon_version{std::min(peer_recon_version, m_recon_version)};
         // v1 is the lowest version, so suggesting something below must be a protocol violation.
-        if (recon_version < 1) return PROTOCOL_VIOLATION;
-
-        // Must match SENDTXRCNCL logic.
-        const bool they_initiate = is_peer_recon_initiator && is_peer_inbound;
-        const bool we_initiate = !is_peer_inbound && is_peer_recon_responder;
-
-        // If we ever announce support for both requesting and responding, this will need
-        // tie-breaking. For now, this is mutually exclusive because both are based on the
-        // inbound flag.
-        assert(!(they_initiate && we_initiate));
-
-        // The peer set both flags to false, we treat it as a protocol violation.
-        if (!(they_initiate || we_initiate)) return PROTOCOL_VIOLATION;
+        if (recon_version < 1) return ReconciliationRegisterResult::PROTOCOL_VIOLATION;
 
-        LogPrintLevel(BCLog::TXRECONCILIATION, BCLog::Level::Debug, "Register peer=%d with the following params: " /* Continued */
-                                                                    "we_initiate=%i, they_initiate=%i.\n",
-                      peer_id, we_initiate, they_initiate);
+        LogPrintLevel(BCLog::TXRECONCILIATION, BCLog::Level::Debug, "Register peer=%d (inbound=%i)\n",
+                      peer_id, is_peer_inbound);
 
-        const uint256 full_salt{ComputeSalt(*local_salt, remote_salt)};
-        recon_state->second = TxReconciliationState(we_initiate, full_salt.GetUint64(0), full_salt.GetUint64(1));
-        return SUCCESS;
+        const uint256 full_salt{ComputeSalt(local_salt, remote_salt)};
+        recon_state->second = TxReconciliationState(!is_peer_inbound, full_salt.GetUint64(0), full_salt.GetUint64(1));
+        return ReconciliationRegisterResult::SUCCESS;
     }
 
     void ForgetPeer(NodeId peer_id) EXCLUSIVE_LOCKS_REQUIRED(!m_txreconciliation_mutex)
@@ -166,11 +153,9 @@ uint64_t TxReconciliationTracker::PreRegisterPeer(NodeId peer_id)
 }
 
 ReconciliationRegisterResult TxReconciliationTracker::RegisterPeer(NodeId peer_id, bool is_peer_inbound,
-                                                          bool is_peer_recon_initiator, bool is_peer_recon_responder,
                                                           uint32_t peer_recon_version, uint64_t remote_salt)
 {
-    return m_impl->RegisterPeer(peer_id, is_peer_inbound, is_peer_recon_initiator, is_peer_recon_responder,
-                                peer_recon_version, remote_salt);
+    return m_impl->RegisterPeer(peer_id, is_peer_inbound, peer_recon_version, remote_salt);
 }
 
 void TxReconciliationTracker::ForgetPeer(NodeId peer_id)

src/node/txreconciliation.h

@@ -16,10 +16,11 @@ static constexpr bool DEFAULT_TXRECONCILIATION_ENABLE{false};
 /** Supported transaction reconciliation protocol version */
 static constexpr uint32_t TXRECONCILIATION_VERSION{1};
 
-enum ReconciliationRegisterResult {
-    NOT_FOUND = 0,
-    SUCCESS = 1,
-    PROTOCOL_VIOLATION = 2,
+enum class ReconciliationRegisterResult {
+    NOT_FOUND,
+    SUCCESS,
+    ALREADY_REGISTERED,
+    PROTOCOL_VIOLATION,
 };
 
 /**
@@ -72,8 +73,8 @@ class TxReconciliationTracker
      * Step 0. Once the peer agreed to reconcile txs with us, generate the state required to track
      * ongoing reconciliations. Must be called only after pre-registering the peer and only once.
      */
-    ReconciliationRegisterResult RegisterPeer(NodeId peer_id, bool is_peer_inbound, bool is_peer_recon_initiator,
-                                     bool is_peer_recon_responder, uint32_t peer_recon_version, uint64_t remote_salt);
+    ReconciliationRegisterResult RegisterPeer(NodeId peer_id, bool is_peer_inbound,
+                                              uint32_t peer_recon_version, uint64_t remote_salt);
 
     /**
      * Attempts to forget txreconciliation-related state of the peer (if we previously stored any).

src/protocol.h

@@ -259,9 +259,7 @@ extern const char* CFCHECKPT;
  */
 extern const char* WTXIDRELAY;
 /**
- * Contains 2 1-byte bools, a 4-byte version number and an 8-byte salt.
- * The 2 booleans indicate that a node is willing to participate in transaction
- * reconciliation, respectively as an initiator or as a receiver.
+ * Contains a 4-byte version number and an 8-byte salt.
  * The salt is used to compute short txids needed for efficient
  * txreconciliation, as described by BIP 330.
  */