From 37a934e6b35bea2125732d2c074998d9fe70633e Mon Sep 17 00:00:00 2001
From: John Newbery <john@johnnewbery.com>
Date: Fri, 10 Jul 2020 16:48:20 +0100
Subject: [PATCH 1/2] [protocol] Remove unused CADDR_TIME_VERSION

Add comments to CAddress serialization code explaining why
it's no longer needed.
---
 src/protocol.h                             |  8 +++++++-
 src/version.h                              |  4 ----
 test/functional/test_framework/messages.py | 14 ++++++++------
 3 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/src/protocol.h b/src/protocol.h
index 985f44640bd..9ab63a30fbf 100644
--- a/src/protocol.h
+++ b/src/protocol.h
@@ -371,7 +371,13 @@ public:
             READWRITE(nVersion);
         }
         if ((s.GetType() & SER_DISK) ||
-            (nVersion >= CADDR_TIME_VERSION && !(s.GetType() & SER_GETHASH))) {
+            (nVersion != INIT_PROTO_VERSION && !(s.GetType() & SER_GETHASH))) {
+            // The only time we serialize a CAddress object without nTime is in
+            // the initial VERSION messages which contain two CAddress records.
+            // At that point, the serialization version is INIT_PROTO_VERSION.
+            // After the version handshake, serialization version is >=
+            // MIN_PEER_PROTO_VERSION and all ADDR messages are serialized with
+            // nTime.
             READWRITE(obj.nTime);
         }
         READWRITE(Using<CustomUintFormatter<8>>(obj.nServices));
diff --git a/src/version.h b/src/version.h
index d932b512d4b..d2a747fab3c 100644
--- a/src/version.h
+++ b/src/version.h
@@ -20,10 +20,6 @@ static const int GETHEADERS_VERSION = 31800;
 //! disconnect from peers older than this proto version
 static const int MIN_PEER_PROTO_VERSION = GETHEADERS_VERSION;
 
-//! nTime field added to CAddress, starting with this version;
-//! if possible, avoid requesting addresses nodes older than this
-static const int CADDR_TIME_VERSION = 31402;
-
 //! BIP 0031, pong message, is enabled for all versions AFTER this one
 static const int BIP0031_VERSION = 60000;
 
diff --git a/test/functional/test_framework/messages.py b/test/functional/test_framework/messages.py
index eb1244035f7..12302cdbc3d 100755
--- a/test/functional/test_framework/messages.py
+++ b/test/functional/test_framework/messages.py
@@ -207,17 +207,19 @@ class CAddress:
         self.ip = "0.0.0.0"
         self.port = 0
 
-    def deserialize(self, f, with_time=True):
+    def deserialize(self, f, *, with_time=True):
         if with_time:
+            # VERSION messages serialize CAddress objects without time
             self.time = struct.unpack("<i", f.read(4))[0]
         self.nServices = struct.unpack("<Q", f.read(8))[0]
         self.pchReserved = f.read(12)
         self.ip = socket.inet_ntoa(f.read(4))
         self.port = struct.unpack(">H", f.read(2))[0]
 
-    def serialize(self, with_time=True):
+    def serialize(self, *, with_time=True):
         r = b""
         if with_time:
+            # VERSION messages serialize CAddress objects without time
             r += struct.pack("<i", self.time)
         r += struct.pack("<Q", self.nServices)
         r += self.pchReserved
@@ -973,10 +975,10 @@ class msg_version:
         self.nServices = struct.unpack("<Q", f.read(8))[0]
         self.nTime = struct.unpack("<q", f.read(8))[0]
         self.addrTo = CAddress()
-        self.addrTo.deserialize(f, False)
+        self.addrTo.deserialize(f, with_time=False)
 
         self.addrFrom = CAddress()
-        self.addrFrom.deserialize(f, False)
+        self.addrFrom.deserialize(f, with_time=False)
         self.nNonce = struct.unpack("<Q", f.read(8))[0]
         self.strSubVer = deser_string(f)
 
@@ -996,8 +998,8 @@ class msg_version:
         r += struct.pack("<i", self.nVersion)
         r += struct.pack("<Q", self.nServices)
         r += struct.pack("<q", self.nTime)
-        r += self.addrTo.serialize(False)
-        r += self.addrFrom.serialize(False)
+        r += self.addrTo.serialize(with_time=False)
+        r += self.addrFrom.serialize(with_time=False)
         r += struct.pack("<Q", self.nNonce)
         r += ser_string(self.strSubVer)
         r += struct.pack("<i", self.nStartingHeight)

From 7bb6f9bfdbd3b0b5594febc9a0ae2f84e6d7add1 Mon Sep 17 00:00:00 2001
From: John Newbery <john@johnnewbery.com>
Date: Fri, 10 Jul 2020 16:52:05 +0100
Subject: [PATCH 2/2] [protocol] Remove unused GETHEADERS_VERSION

GETHEADERS_VERSION is unused. No need to keep it in the codebase
for just its historic comment.
---
 src/version.h | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/src/version.h b/src/version.h
index d2a747fab3c..e5d1f5a7f99 100644
--- a/src/version.h
+++ b/src/version.h
@@ -14,11 +14,8 @@ static const int PROTOCOL_VERSION = 70015;
 //! initial proto version, to be increased after version/verack negotiation
 static const int INIT_PROTO_VERSION = 209;
 
-//! In this version, 'getheaders' was introduced.
-static const int GETHEADERS_VERSION = 31800;
-
 //! disconnect from peers older than this proto version
-static const int MIN_PEER_PROTO_VERSION = GETHEADERS_VERSION;
+static const int MIN_PEER_PROTO_VERSION = 31800;
 
 //! BIP 0031, pong message, is enabled for all versions AFTER this one
 static const int BIP0031_VERSION = 60000;