From 4a280716a61dc84544ec1ade1e966cfd7e1abbce Mon Sep 17 00:00:00 2001
From: Nico Schottelius <nico@nico-notebook.schottelius.org>
Date: Mon, 25 Mar 2019 12:11:20 +0100
Subject: [PATCH] Rewrite code to use unique destination networks

---
 p4app/controller.py     | 33 ++++++++++++++++++++++++++-------
 p4src/static-mapping.p4 |  4 ++--
 2 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/p4app/controller.py b/p4app/controller.py
index c2ae8ee..a9fea7f 100755
--- a/p4app/controller.py
+++ b/p4app/controller.py
@@ -54,13 +54,17 @@ class L2Controller(object):
         self.info['ipv6_link_local'] = ipaddress.ip_address("fe80::200:aff:fe00:42")
 
         self.info['v6_mask'] = 64
+        self.info['v6_nat64_mask'] = 96
         self.info['v6_base'] = ipaddress.ip_network("2001:db8::/32")
+
         self.info['v6_base_hostnet'] = ipaddress.ip_network("2001:db8::/48")
+        self.info['v6_gen'] = self.info['v6_base_hostnet'].subnets(new_prefix=self.info['v6_mask'])
 
         # possible new range for NAT64 prefixes
-        self.info['v6_base_nat64']   = ipaddress.ip_network("2001:db8:1::/48")
+        self.info['v6_nat64_base']  = ipaddress.ip_network("2001:db8:1::/48")
 
-        self.info['v6_gen'] = self.info['v6_base_hostnet'].subnets(new_prefix=self.info['v6_mask'])
+        # We reserve /64 (easier for reading), but only use /96
+        self.info['v6_nat64_gen']   = self.info['v6_nat64_base'].subnets(new_prefix=self.info['v6_mask'])
 
         self.info['v4_mask'] = 24
         self.info['v4_base'] = ipaddress.ip_network("10.0.0.0/8")
@@ -123,12 +127,19 @@ class L2Controller(object):
         # specific settings - mapping 256 IPv6 IPs max statically (based on /24)
         for mode in ["range_router"]:
             for v6_net in self.v6_routes[mode]:
+                # This is a /64
+                v6_dst_base = self.info['v6_nat64_base'].next()
+
+                # This is a /96xs!
+                v6_dst = v6_dst_base.subnets(new_prefix=self.info['v6_nat64_mask']).next()
+
                 for v4_net in self.v4_routes[mode]:
                     v4_dst = self.info['v4_nat64_map'].next()
 
                 self.nat64_map[mode].append({
                     "v6_src": v6_net['net'],
-                    "v6_dst": self.info['nat64_prefix'] # static
+                    # "v6_dst": self.info['nat64_prefix'] # static -- not supported ATM
+                    "v6_dst": v6_dst
                     "v4_src": v4_net['net'],
                     "v4_dst": v4_dst
                 })
@@ -241,21 +252,29 @@ class L2Controller(object):
         #     self.controller.table_add("v6_addresses", "controller_reply", [str(another_addr_ns)], [str(self.task['ICMP6_NS'])])
 
     def static_nat64_mapping(self, v6_src, v6_dst, v4_src, v4_dst):
+        """
+        Currently using destination only matching due to non priority
+        LPM support in P4
+
+        This could be solved with ternary matches or smart double table usage
+
+        """
+
         log.info("NAT64 map: ({} -> {} => {}), ({} -> {} -> {} (only /24)))".format(
             v6_src, v6_dst, v4_dst,
             v4_src, v4_dst, v6_src)
 
         self.controller.table_add("nat64", "nat64_static",
-                                  [str(v6_src)
-                                   str(v6_dst)],
+#                                  [str(v6_src)
+                                   [str(v6_dst)],
                                   [str(v6_src.network_address),
                                    str(v4_dst.network_address),
                                    str(v6_dst.network_address)]
         )
 
         self.controller.table_add("nat46", "nat46_static",
-                                  [str(v4_src)
-                                   str(v4_dst)],
+#                                  [str(v4_src)
+                                  [str(v4_dst)],
                                   [str(v6_src.network_address),
                                    str(v4_dst.network_address),
                                    str(v6_dst.network_address)]
diff --git a/p4src/static-mapping.p4 b/p4src/static-mapping.p4
index 2eeb875..0007a50 100644
--- a/p4src/static-mapping.p4
+++ b/p4src/static-mapping.p4
@@ -120,7 +120,7 @@ control MyIngress(inout headers hdr,
 
     table nat64 {
         key = {
-            hdr.ipv6.src_addr: lpm;
+//            hdr.ipv6.src_addr: lpm;
             hdr.ipv6.dst_addr: lpm;
         }
         actions = {
@@ -134,7 +134,7 @@ control MyIngress(inout headers hdr,
 
     table nat46 {
         key = {
-            hdr.ipv4.src_addr: lpm;
+//            hdr.ipv4.src_addr: lpm;
             hdr.ipv4.dst_addr: lpm;
         }
         actions = {