A packet can have multiple TLVs

Signed-off-by: Yohann D'ANELLO <ynerant@crans.org>

squinnondation/squinnondation.py

@@ -6,7 +6,7 @@ from argparse import ArgumentParser
 from enum import Enum
 from ipaddress import IPv6Address
 from threading import Thread
-from typing import Any, Optional, Tuple
+from typing import Any, List, Optional, Tuple
 
 
 class Squinnondation:
@@ -50,13 +50,14 @@ class Squinnondation:
             pkt = Packet()
             pkt.magic = 95
             pkt.version = 0
-            pkt.body = DataTLV()
+            tlv = DataTLV()
             msg = f"Hello world, my name is {squirrel.nickname}!"
-            pkt.body.data = msg.encode("UTF-8")
-            pkt.body.sender_id = 42
-            pkt.body.nonce = 18
-            pkt.body.length = len(msg) + 1 + 1 + 8 + 4
-            pkt.body_length = pkt.body.length + 2
+            tlv.data = msg.encode("UTF-8")
+            tlv.sender_id = 42
+            tlv.nonce = 18
+            tlv.length = len(msg) + 1 + 1 + 8 + 4
+            pkt.body = [tlv]
+            pkt.body_length = tlv.length + 2
             squirrel.send_packet(hazelnut, pkt)
 
         Worm(squirrel).start()
@@ -275,7 +276,7 @@ class Packet:
     magic: int
     version: int
     body_length: int
-    body: TLV
+    body: List[TLV]
 
     def validate_data(self) -> bool:
         """
@@ -289,7 +290,7 @@ class Packet:
         if not (0 <= self.body_length <= 120):
             raise ValueError("The body length of the packet is negative or too high. It must be between 0 and 1020,"
                              "found: {:d}".format(self.body_length))
-        return self.body.validate_data()
+        return all(tlv.validate_data() for tlv in self.body)
 
     @staticmethod
     def unmarshal(data: bytes) -> "Packet":
@@ -301,11 +302,17 @@ class Packet:
         pkt.magic = data[0]
         pkt.version = data[1]
         pkt.body_length = int.from_bytes(data[2:4], byteorder="big")
+        pkt.body = []
+        read_bytes = 0
+        while read_bytes <= min(len(data) - 4, pkt.body_length):
             tlv_type = data[4]
             if not (0 <= tlv_type < len(TLV.tlv_classes())):
                 raise ValueError(f"TLV type is not supported: {tlv_type}")
-        pkt.body = TLV.tlv_classes()[tlv_type]()
-        pkt.body.unmarshal(data[4:4 + pkt.body_length])
+            tlv = TLV.tlv_classes()[tlv_type]()
+            tlv.unmarshal(data[4:4 + pkt.body_length])
+            pkt.body.append(tlv)
+            # Pad1TLV has no length
+            read_bytes += 1 if tlv_type == 0 else tlv.length + 2
 
         pkt.validate_data()
 
@@ -318,7 +325,7 @@ class Packet:
         data = self.magic.to_bytes(1, "big")
         data += self.version.to_bytes(1, "big")
         data += self.body_length.to_bytes(2, "big")
-        data += self.body.marshal()
+        data += b"".join(tlv.marshal() for tlv in self.body)
         return data
 
 
@@ -410,15 +417,17 @@ class Worm(Thread):
             except ValueError as error:
                 print("An error occured while receiving a packet: ", error)
             else:
-                print(pkt.body.data.decode('UTF-8'))
+                print(pkt.body[0].data.decode('UTF-8'))
                 pkt = Packet()
                 pkt.magic = 95
                 pkt.version = 0
-                pkt.body = DataTLV()
+                pkt.body = []
+                tlv = DataTLV()
                 msg = f"Hello my dear hazelnut, I am {self.squirrel.nickname}!"
-                pkt.body.data = msg.encode("UTF-8")
-                pkt.body.sender_id = 42
-                pkt.body.nonce = 18
-                pkt.body.length = len(msg) + 1 + 1 + 8 + 4
-                pkt.body_length = pkt.body.length + 2
+                tlv.data = msg.encode("UTF-8")
+                tlv.sender_id = 42
+                tlv.nonce = 18
+                tlv.length = len(msg) + 1 + 1 + 8 + 4
+                pkt.body.append(tlv)
+                pkt.body_length = tlv.length + 2
                 self.squirrel.send_packet(hazelnut, pkt)