Fix #4547: Change hashret of DoIP (#4586)

* Fix #4547: Change hashret of DoIP

* debug

* update timeout

Author: polybassa

scapy/contrib/automotive/doip.py

@@ -239,10 +239,7 @@ def answers(self, other):
 
     def hashret(self):
         # type: () -> bytes
-        if self.payload_type in [0x8001, 0x8002, 0x8003]:
-            return bytes(self)[:2] + struct.pack(
-                "H", self.target_address ^ self.source_address)
-        return bytes(self)[:2]
+        return bytes(self)[:3]
 
     def post_build(self, pkt, pay):
         # type: (bytes, bytes) -> bytes

test/contrib/automotive/doip.uts

@@ -10,6 +10,8 @@
 
 = Load Contrib Layer
 
+from test.testsocket import TestSocket, cleanup_testsockets, UnstableSocket
+
 load_contrib("automotive.doip", globals_dict=globals())
 load_contrib("automotive.uds", globals_dict=globals())
 
@@ -406,6 +408,30 @@ assert pkts[0][DoIP].payload_length == 2
 assert pkts[0][DoIP:2].payload_length == 7
 assert pkts[1][DoIP].payload_length == 103
 
+= Doip logical addressing
+
+filename = scapy_path("/test/pcaps/doip_functional_request.pcap.gz")
+tx_sock = TestSocket(DoIP)
+rx_sock = TestSocket(DoIP)
+tx_sock.pair(rx_sock)
+
+for pkt in PcapReader(filename):
+    if pkt.haslayer(DoIP):
+        tx_sock.send(pkt[DoIP])
+
+ans, unans = rx_sock.sr(DoIP(bytes(DoIP(payload_type=0x8001, source_address=0xe80, target_address=0xe400) / UDS() / UDS_TP())), multi=True, timeout=0.1, verbose=False)
+
+cleanup_testsockets()
+
+ans.summary()
+if unans:
+    unans.summary()
+
+assert len(ans) == 8
+ans.summary()
+assert len(unans) == 0
+
+
 + DoIP Communication tests
 
 = Load libraries