Refactor ICMPv4 message parsing for code clarity.

ccie18643 · Jul 14, 2024 · c5097f7 · c5097f7
1 parent 1674f0b
commit c5097f7
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Showing 5 changed files with 39 additions and 12 deletions.
diff --git a/pytcp/protocols/icmp4/message__echo_reply.py b/pytcp/protocols/icmp4/message__echo_reply.py
@@ -121,6 +121,15 @@ def __bytes__(self) -> bytes:
             bytes(self._data),
         )
 
+    def _parse(self, *, frame: bytes) -> None:
+        """
+        Parse message from the frame.
+        """
+
+        self._id: int = struct.unpack("! H", frame[4:6])[0]
+        self._seq: int = struct.unpack("! H", frame[6:8])[0]
+        self._data: bytes = frame[8:]
+
     @property
     def id(self) -> int:
         """

diff --git a/pytcp/protocols/icmp4/message__echo_request.py b/pytcp/protocols/icmp4/message__echo_request.py
@@ -123,6 +123,15 @@ def __bytes__(self) -> bytes:
             bytes(self._data),
         )
 
+    def _parse(self, *, frame: bytes) -> None:
+        """
+        Parse the message from the frame.
+        """
+
+        self._id: int = struct.unpack("! H", frame[4:6])[0]
+        self._seq: int = struct.unpack("! H", frame[6:8])[0]
+        self._data: bytes = frame[8:]
+
     @property
     def id(self) -> int:
         """

diff --git a/pytcp/protocols/icmp4/message__unknown.py b/pytcp/protocols/icmp4/message__unknown.py
@@ -83,3 +83,11 @@ def __bytes__(self) -> bytes:
         """
 
         raise NotImplementedError
+
+    def _parse(self, *, frame: bytes) -> None:
+        """
+        Parse message from the frame.
+        """
+
+        self._type = Icmp4Type.from_frame(frame)
+        self._code = Icmp4Code.from_frame(frame)
diff --git a/pytcp/protocols/icmp4/message__unreachable.py b/pytcp/protocols/icmp4/message__unreachable.py
@@ -147,3 +147,10 @@ def __bytes__(self) -> bytes:
             self._reserved,
             bytes(self._data),
         )
+
+    def _parse(self, *, frame: bytes) -> None:
+        """
+        Parse message from the frame.
+        """
+
+        self._data: bytes = frame[8:]
diff --git a/pytcp/protocols/icmp4/parser.py b/pytcp/protocols/icmp4/parser.py
@@ -37,14 +37,13 @@
 
 from __future__ import annotations
 
-import struct
 from typing import TYPE_CHECKING, override
 
 from pytcp.lib.errors import PacketIntegrityError, PacketSanityError
 from pytcp.lib.ip_helper import inet_cksum
 from pytcp.lib.proto import ProtoParser
 from pytcp.protocols.icmp4.base import Icmp4
-from pytcp.protocols.icmp4.message import ICMP4_HEADER_LEN, Icmp4Code, Icmp4Type
+from pytcp.protocols.icmp4.message import ICMP4_HEADER_LEN, Icmp4Type
 from pytcp.protocols.icmp4.message__echo_reply import (
     ICMP4_MESSAGE_LEN__ECHO_REPLY,
     Icmp4EchoReplyMessage,
@@ -221,9 +220,7 @@ def __init__(self, *, frame: bytes) -> None:
         Class constructor.
         """
 
-        self._id: int = struct.unpack("! H", frame[4:6])[0]
-        self._seq: int = struct.unpack("! H", frame[6:8])[0]
-        self._data: bytes = frame[8:]
+        self._parse(frame=frame)
 
 
 class Icmp4UnreachablePortMessageParser(Icmp4PortUnreachableMessage):
@@ -236,7 +233,7 @@ def __init__(self, *, frame: bytes) -> None:
         Class constructor.
         """
 
-        self._data: bytes = frame[8:]
+        self._parse(frame=frame)
 
 
 class Icmp4EchoRequestMessageParser(Icmp4EchoRequestMessage):
@@ -249,9 +246,7 @@ def __init__(self, *, frame: bytes) -> None:
         Class constructor.
         """
 
-        self._id: int = struct.unpack("! H", frame[4:6])[0]
-        self._seq: int = struct.unpack("! H", frame[6:8])[0]
-        self._data: bytes = frame[8:]
+        self._parse(frame=frame)
 
 
 class Icmp4UnknownMessageParser(Icmp4UnknownMessage):
@@ -261,8 +256,7 @@ class Icmp4UnknownMessageParser(Icmp4UnknownMessage):
 
     def __init__(self, *, frame: bytes) -> None:
         """
-        Create the message object.
+        Class constructor.
         """
 
-        self._type = Icmp4Type.from_frame(frame)
-        self._code = Icmp4Code.from_frame(frame)
+        self._parse(frame=frame)