From c9f88318655ac3242c0bf400bc6cca613dbabfeb Mon Sep 17 00:00:00 2001
From: Nico Schottelius <nico@nico-notebook.schottelius.org>
Date: Tue, 5 Mar 2019 22:04:04 +0100
Subject: [PATCH] icmp6 echo reply

---
 p4app/controller.py | 30 ++++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/p4app/controller.py b/p4app/controller.py
index 3ea4d9b..382f95c 100644
--- a/p4app/controller.py
+++ b/p4app/controller.py
@@ -11,6 +11,7 @@ from scapy.all import IP, Raw, IPv6, TCP, TCP_client, Ether
 from scapy.all import sniff
 from scapy.all import Packet, BitField, IntEnumField, ShortField, XShortEnumField, ShortEnumField
 from scapy.all import ICMPv6ND_NS, ICMPv6ND_RS, ICMPv6NDOptSrcLLAddr, ICMPv6ND_NS, ICMPv6ND_NA, ICMPv6NDOptDstLLAddr
+from scapy.all import ICMPv6EchoRequest, ICMPv6EchoReply
 from scapy.data import ETHER_TYPES
 
 import sys
@@ -230,6 +231,29 @@ class L2Controller(object):
         #     tcp.ack,
         #     raw)
 
+    def handle_icmp6_echo_request(self, pkg):
+        """
+        Sample from the wire:
+
+        DEBUG:main:reassambled=<Ether  dst=00:00:0a:00:00:42 src=00:00:0a:00:00:01 type=0x86dd |<IPv6  version=6 tc=0 fl=474570 plen=64 nh=ICMPv6 hlim=64 src=2001:db8::1 dst=2001:db8::42 |<ICMPv6EchoRequest  type=Echo Request code=0 cksum=0xb76d id=0x16cd seq=0x1 data='\x1f\xe2~\\\x00\x00\x00\x00\xf8\x82\x00\x00\x00\x00\x00\x00\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !"#$%&\'()*+,-./01234567' |>>>
+        """
+
+        log.info("Replying to ICMP packet")
+        dst_mac = pkg[Ether].src
+        src_mac = pkg[Ether].dst
+
+        dst_addr = pkg[IPv6].src
+        src_addr = pkg[IPv6].dst
+
+        e = Ether(src=src_mac, dst=dst_mac)
+        i = IPv6(src=src_addr, dst=dst_addr)
+        i2 = ICMPv6EchoReply(id=pkg[ICMPv6EchoRequest].id,
+                             seq=pkg[ICMPv6EchoRequest].seq,
+                             data=pkg[ICMPv6EchoRequest].data)
+        i2.cksum = None
+        self.send_pkg(answer)
+
+
     def handle_icmp6_ns(self, pkg):
         """ Solicitated NA"""
 
@@ -263,9 +287,6 @@ class L2Controller(object):
         # Let scapy recalc checksum (try3)
         # answer = answer.__class__(str(answer))
 
-
-
-
         self.send_pkg(answer)
 
     def send_pkg(self, pkg):
@@ -295,7 +316,8 @@ class L2Controller(object):
                 log.info("Doing neighbor solicitation")
                 self.handle_icmp6_ns(orig_packet)
             elif cpu_header.task == self.task['ICMP6_GENERAL']:
-                log.info("Replying to ICMP packet")
+                if ICMPv6EchoRequest in orig_packet:
+                    handle_icmp6_echo_request(orig_packet)
 
         else:
             print("Broken pkg: {}".format(pkg.__repr__()))