net: Clarify message header validation errors

Make the errors less shouty and more descriptive.

Author: laanwj

src/net.cpp

@@ -681,19 +681,19 @@ int V1TransportDeserializer::readHeader(Span<const uint8_t> msg_bytes)
         hdrbuf >> hdr;
     }
     catch (const std::exception&) {
-        LogPrint(BCLog::NET, "HEADER ERROR - UNABLE TO DESERIALIZE, peer=%d\n", m_node_id);
+        LogPrint(BCLog::NET, "Header error: Unable to deserialize, peer=%d\n", m_node_id);
         return -1;
     }
 
     // Check start string, network magic
     if (memcmp(hdr.pchMessageStart, m_chain_params.MessageStart(), CMessageHeader::MESSAGE_START_SIZE) != 0) {
-        LogPrint(BCLog::NET, "HEADER ERROR - MESSAGESTART received %s, peer=%d\n", HexStr(hdr.pchMessageStart), m_node_id);
+        LogPrint(BCLog::NET, "Header error: Wrong MessageStart %s received, peer=%d\n", HexStr(hdr.pchMessageStart), m_node_id);
         return -1;
     }
 
     // reject messages larger than MAX_SIZE or MAX_PROTOCOL_MESSAGE_LENGTH
     if (hdr.nMessageSize > MAX_SIZE || hdr.nMessageSize > MAX_PROTOCOL_MESSAGE_LENGTH) {
-        LogPrint(BCLog::NET, "HEADER ERROR - SIZE (%s, %u bytes), peer=%d\n", SanitizeString(hdr.GetCommand()), hdr.nMessageSize, m_node_id);
+        LogPrint(BCLog::NET, "Header error: Size too large (%s, %u bytes), peer=%d\n", SanitizeString(hdr.GetCommand()), hdr.nMessageSize, m_node_id);
         return -1;
     }
 
@@ -746,15 +746,15 @@ std::optional<CNetMessage> V1TransportDeserializer::GetMessage(const std::chrono
 
     // Check checksum and header command string
     if (memcmp(hash.begin(), hdr.pchChecksum, CMessageHeader::CHECKSUM_SIZE) != 0) {
-        LogPrint(BCLog::NET, "CHECKSUM ERROR (%s, %u bytes), expected %s was %s, peer=%d\n",
+        LogPrint(BCLog::NET, "Header error: Wrong checksum (%s, %u bytes), expected %s was %s, peer=%d\n",
                  SanitizeString(msg->m_command), msg->m_message_size,
                  HexStr(Span<uint8_t>(hash.begin(), hash.begin() + CMessageHeader::CHECKSUM_SIZE)),
                  HexStr(hdr.pchChecksum),
                  m_node_id);
         out_err_raw_size = msg->m_raw_message_size;
         msg = std::nullopt;
     } else if (!hdr.IsCommandValid()) {
-        LogPrint(BCLog::NET, "HEADER ERROR - COMMAND (%s, %u bytes), peer=%d\n",
+        LogPrint(BCLog::NET, "Header error: Invalid message type (%s, %u bytes), peer=%d\n",
                  SanitizeString(hdr.GetCommand()), msg->m_message_size, m_node_id);
         out_err_raw_size = msg->m_raw_message_size;
         msg.reset();

test/functional/p2p_invalid_messages.py

@@ -104,7 +104,7 @@ def test_duplicate_version_msg(self):
     def test_magic_bytes(self):
         self.log.info("Test message with invalid magic bytes disconnects peer")
         conn = self.nodes[0].add_p2p_connection(P2PDataStore())
-        with self.nodes[0].assert_debug_log(['HEADER ERROR - MESSAGESTART received ffffffff']):
+        with self.nodes[0].assert_debug_log(['Header error: Wrong MessageStart ffffffff received']):
             msg = conn.build_message(msg_unrecognized(str_data="d"))
             # modify magic bytes
             msg = b'\xff' * 4 + msg[4:]
@@ -115,7 +115,7 @@ def test_magic_bytes(self):
     def test_checksum(self):
         self.log.info("Test message with invalid checksum logs an error")
         conn = self.nodes[0].add_p2p_connection(P2PDataStore())
-        with self.nodes[0].assert_debug_log(['CHECKSUM ERROR (badmsg, 2 bytes), expected 78df0a04 was ffffffff']):
+        with self.nodes[0].assert_debug_log(['Header error: Wrong checksum (badmsg, 2 bytes), expected 78df0a04 was ffffffff']):
             msg = conn.build_message(msg_unrecognized(str_data="d"))
             # Checksum is after start bytes (4B), message type (12B), len (4B)
             cut_len = 4 + 12 + 4
@@ -130,7 +130,7 @@ def test_checksum(self):
     def test_size(self):
         self.log.info("Test message with oversized payload disconnects peer")
         conn = self.nodes[0].add_p2p_connection(P2PDataStore())
-        with self.nodes[0].assert_debug_log(['HEADER ERROR - SIZE (badmsg, 4000001 bytes)']):
+        with self.nodes[0].assert_debug_log(['Header error: Size too large (badmsg, 4000001 bytes)']):
             msg = msg_unrecognized(str_data="d" * (VALID_DATA_LIMIT + 1))
             msg = conn.build_message(msg)
             conn.send_raw_message(msg)
@@ -140,7 +140,7 @@ def test_size(self):
     def test_msgtype(self):
         self.log.info("Test message with invalid message type logs an error")
         conn = self.nodes[0].add_p2p_connection(P2PDataStore())
-        with self.nodes[0].assert_debug_log(['HEADER ERROR - COMMAND']):
+        with self.nodes[0].assert_debug_log(['Header error: Invalid message type']):
             msg = msg_unrecognized(str_data="d")
             msg = conn.build_message(msg)
             # Modify msgtype