Send and require SENDADDRV2 before VERACK

See the corresponding BIP change: bitcoin/bips#1043

Author: sipa

src/net_processing.cpp

@@ -2362,8 +2362,6 @@ void PeerManager::ProcessMessage(CNode& pfrom, const std::string& msg_type, CDat
             m_connman.PushMessage(&pfrom, msg_maker.Make(NetMsgType::WTXIDRELAY));
         }
 
-        m_connman.PushMessage(&pfrom, msg_maker.Make(NetMsgType::VERACK));
-
         // Signal ADDRv2 support (BIP155).
         if (greatest_common_version >= 70016) {
             // BIP155 defines addrv2 and sendaddrv2 for all protocol versions, but some
@@ -2373,6 +2371,8 @@ void PeerManager::ProcessMessage(CNode& pfrom, const std::string& msg_type, CDat
             m_connman.PushMessage(&pfrom, msg_maker.Make(NetMsgType::SENDADDRV2));
         }
 
+        m_connman.PushMessage(&pfrom, msg_maker.Make(NetMsgType::VERACK));
+
         pfrom.nServices = nServices;
         pfrom.SetAddrLocal(addrMe);
         {
@@ -2541,6 +2541,17 @@ void PeerManager::ProcessMessage(CNode& pfrom, const std::string& msg_type, CDat
         return;
     }
 
+    if (msg_type == NetMsgType::SENDADDRV2) {
+        if (pfrom.fSuccessfullyConnected) {
+            // Disconnect peers that send SENDADDRV2 message after VERACK; this
+            // must be negotiated between VERSION and VERACK.
+            pfrom.fDisconnect = true;
+            return;
+        }
+        pfrom.m_wants_addrv2 = true;
+        return;
+    }
+
     if (!pfrom.fSuccessfullyConnected) {
         LogPrint(BCLog::NET, "Unsupported message \"%s\" prior to verack from peer=%d\n", SanitizeString(msg_type), pfrom.GetId());
         return;
@@ -2608,11 +2619,6 @@ void PeerManager::ProcessMessage(CNode& pfrom, const std::string& msg_type, CDat
         return;
     }
 
-    if (msg_type == NetMsgType::SENDADDRV2) {
-        pfrom.m_wants_addrv2 = true;
-        return;
-    }
-
     if (msg_type == NetMsgType::SENDHEADERS) {
         LOCK(cs_main);
         State(pfrom.GetId())->fPreferHeaders = true;

test/functional/test_framework/p2p.py

@@ -396,9 +396,9 @@ def on_version(self, message):
         assert message.nVersion >= MIN_VERSION_SUPPORTED, "Version {} received. Test framework only supports versions greater than {}".format(message.nVersion, MIN_VERSION_SUPPORTED)
         if message.nVersion >= 70016:
             self.send_message(msg_wtxidrelay())
-        self.send_message(msg_verack())
         if self.support_addrv2:
             self.send_message(msg_sendaddrv2())
+        self.send_message(msg_verack())
         self.nServices = message.nServices
 
     # Connection helper methods