test: BIP324: add checks for v1 prefix matching / wrong network magic detection

[theStack]

This PR adds missing test coverage for the detection of incoming v1 connections and wrong network magic on BIP324-enabled (i.e. running with -v2transport=1) nodes. Both checks are using prefix sizes of 16 bytes (previously only 12 bytes were used for the v1 prefix matching, which was fixed by PR #28577).

[DrahtBot]

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Type	Reviewers
ACK	Sjors, MarcoFalke
Stale ACK	sipa

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[sipa]

utACK c8581d4

Happy to rebase #28577 on this if it goes in first.

[theStack]

Rebased on master, now that #28577 is merged. Diff:

diff --git a/test/functional/p2p_v2_transport.py b/test/functional/p2p_v2_transport.py
index 47828867b..dd564fed8 100755                                                                                                        
--- a/test/functional/p2p_v2_transport.py
+++ b/test/functional/p2p_v2_transport.py
@@ -130,9 +130,8 @@ class V2TransportTest(BitcoinTestFramework):                                                                         
         assert_equal(self.nodes[4].getblockcount(), 11)            
                                                                    
         # Check v1 prefix detection                                                                                                     
-        # TODO: this should have the same prefix size as the one used for wrong network magic detection (see below)
-        V1_PREFIX = MAGIC_BYTES["regtest"] + b"version\x00"
-        assert_equal(len(V1_PREFIX), 12)
+        V1_PREFIX = MAGIC_BYTES["regtest"] + b"version\x00\x00\x00\x00\x00"
+        assert_equal(len(V1_PREFIX), 16)
         with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:                                                   
             num_peers = len(self.nodes[0].getpeerinfo())                                                                                
             s.connect(("127.0.0.1", p2p_port(0)))                                                                                       
@@ -143,11 +142,11 @@ class V2TransportTest(BitcoinTestFramework):                                                                       
             self.wait_until(lambda: self.nodes[0].getpeerinfo()[-1]["transport_protocol_type"] == "v1")                                 
                                                                                                                                         
         # Check wrong network prefix detection (hits if the next 12 bytes correspond to a v1 version message)                           
-        wrong_network_magic_prefix = MAGIC_BYTES["signet"] + V1_PREFIX[4:] + b"\x00\x00\x00\00"
+        wrong_network_magic_prefix = MAGIC_BYTES["signet"] + V1_PREFIX[4:]
         with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
             s.connect(("127.0.0.1", p2p_port(0)))
             with self.nodes[0].assert_debug_log("V2 transport error: V1 peer with wrong MessageStart"):
-                s.sendall(wrong_network_magic_prefix)
+                s.sendall(wrong_network_magic_prefix + b"somepayload")

(note that some more data has to be sent after the 12-bytes v1 message type string, to trigger calling the ProcessReceivedKeyBytes method which contains the detection of the wrong network magic prefix)

[Sjors]

utACK e130896

[maflcko]

lgtm ACK e130896