Added support for CoAP

pcap_anonymize/layers/coap.py

+"""
+Anonymize CoAP packets.
+"""
+
+from enum import Enum
+from scapy.contrib.coap import CoAP
+
+
+class CoapFields(Enum):
+    """
+    CoAP fields.
+    """
+    TYPE     = "type"
+    CODE     = "code"
+    OPTIONS  = "options"
+    URI_PATH = "Uri-Path"
+
+
+def anonymize_coap(coap: CoAP) -> None:
+    """
+    Anonymize a packet's CoAP layer.
+
+    Args:
+        coap (scapy.contrib.coap.CoAP): CoAP layer to anonymize
+    """
+    # Remove all fields other than type and code
+    for field in coap.fields.copy():
+        if field not in [f.value for f in CoapFields]:
+            delattr(coap, field)
+
+    # Remove all options other than Uri-Path
+    options = coap.getfieldval(CoapFields.OPTIONS.value)
+    new_options = []
+    for k, v in options:
+        if k == CoapFields.URI_PATH.value:
+            new_options.append((k, v))
+    coap.setfieldval(CoapFields.OPTIONS.value, new_options)

test/test_coap.py

+from scapy.contrib.coap import CoAP
+from pcap_anonymize.layers.coap import CoapFields, anonymize_coap
+
+
+### TEST FUNCTIONS ###
+
+def test_anonymize_coap() -> None:
+    # Build CoAP layer
+    options = [('Uri-Host', 'host'), ('Uri-Path', 'sensors'), ('Uri-Path', 'temperature')]
+    coap = CoAP(type=0, code=1, msg_id=0x1234, token=b"token", options=options)
+
+    anonymize_coap(coap)
+
+    # Check remaining fields
+    assert coap.type == 0
+    assert coap.code == 1
+
+    # Ensure other fields have been deleted
+    for field in coap.fields:
+        assert field in [f.value for f in CoapFields]
+    for k, v in coap.getfieldval(CoapFields.OPTIONS.value):
+        assert k == CoapFields.URI_PATH.value
+        assert v in ["sensors", "temperature"]

test/test_http.py

 from scapy.layers.inet import TCP
-from scapy.layers.http import HTTP, HTTPRequest, HTTPResponse
+from scapy.layers.http import HTTPRequest, HTTPResponse
 from pcap_anonymize.layers.http import (
     HttpFields,
     get_http_layer,