Convert TunTwister's Twisting Methods to Classmethod
Convert the twisting methods so that other classes
can use the logic to twist either Ethernet or IP(vX)
packets without instantiating a Tun/TapTwister
Bug: 67868882
Test: xfrm_algorithm_test.py
Change-Id: I13b58a1c3be7252cb0119da5284dd7c6f6b566dc
diff --git a/net/test/tun_twister.py b/net/test/tun_twister.py
index 53863da..79d85ed 100644
--- a/net/test/tun_twister.py
+++ b/net/test/tun_twister.py
@@ -129,17 +129,19 @@
"""Read, twist, and write one packet on the tun/tap."""
# TODO: Handle EAGAIN "errors".
bytes_in = os.read(self._fd, TunTwister._READ_BUF_SIZE)
- packet = self._DecodePacket(bytes_in)
+ packet = self.DecodePacket(bytes_in)
if self._validator:
self._validator(packet)
- packet = self._TwistPacket(packet)
+ packet = self.TwistPacket(packet)
os.write(self._fd, packet.build())
- def _DecodePacket(self, bytes_in):
+ @classmethod
+ def DecodePacket(cls, bytes_in):
"""Decode a byte array into a scapy object."""
- return self._DecodeIpPacket(bytes_in)
+ return cls._DecodeIpPacket(bytes_in)
- def _TwistPacket(self, packet):
+ @classmethod
+ def TwistPacket(cls, packet):
"""Swap the src and dst in the IP header."""
ip_type = type(packet)
if ip_type not in (scapy.IP, scapy.IPv6):
@@ -180,13 +182,15 @@
"""
super(TapTwister, self).__init__(fd=fd, validator=validator)
- def _DecodePacket(self, bytes_in):
+ @classmethod
+ def DecodePacket(cls, bytes_in):
return scapy.Ether(bytes_in)
- def _TwistPacket(self, packet):
+ @classmethod
+ def TwistPacket(cls, packet):
"""Swap the src and dst in the ethernet and IP headers."""
packet.src, packet.dst = packet.dst, packet.src
ip_layer = packet.payload
- twisted_ip_layer = super(TapTwister, self)._TwistPacket(ip_layer)
+ twisted_ip_layer = super(TapTwister, cls).TwistPacket(ip_layer)
packet.payload = twisted_ip_layer
return packet
