[NDP] Begin to add multicast / NDP support

doc/plan.org

@@ -77,10 +77,11 @@
 ****** rfc4861
 "Neighbor Solicitation messages are multicast to the  solicited-node
 multicast address of the target address."
-****** multicasting / groups
+****** DONE multicasting / groups
 ******* create a group ("node") that contains "all other" ports
 ******* create a multicast group with an ID
 ******* associate the "node" with the multicast group ID
+***** If destination is within ff02::1:ff00:0/104, multicast
 
 **** TODO Make switch answer icmp6 echo request for
 **** TODO Make switch answer icmp echo request for
@@ -156,7 +157,8 @@ user@T:~# iptables  -t mangle -A PREROUTING \
      - IPv4 hosts are in 10.0.4.0/24
      - IPv6 in IPv4 mapped hosts are in 10.0.6.0/24
      - IPv4 default router = 10.0.0.42
-
+**** Neighbor discover protocol
+     - Matching on prefix & ingress port, setting multicast
 **** Static mappings
       - likely need table(s)
       - need tcp & udp translation

p4app/controller.py

@@ -89,6 +89,9 @@ class L2Controller(object):
     def init_ndp(self):
         """ initialise neighbor discovery protocol"""
 
+        # https://en.wikipedia.org/wiki/Solicited-node_multicast_address
+        ndp_prefix = "ff02::1:ff00:0/104"
+
         all_ports = range(1,5)
         # create multicast nodes
         for rid in range(1,5):
@@ -101,6 +104,12 @@ class L2Controller(object):
 
             self.controller.mc_node_associate(g_handle, n_handle)
 
+
+        self.controller.table_clear("ndp")
+        for port in all_ports:
+            self.controller.table_add("ndp", "multicast_pkg", [ndp_prefix, port], [str(port)])
+
+
     def init_boilerplate(self, sw_name):
         self.topo = Topology(db="topology.db")
         self.sw_name = sw_name

p4src/headers.p4

@@ -9,6 +9,7 @@ typedef bit<48>  mac_addr_t;
 typedef bit<32>  ipv4_addr_t;
 typedef bit<128> ipv6_addr_t;
 typedef bit<9>   port_t;
+typedef bit<16>  mcast_t;
 
 
 const bit<16> TYPE_IPV4  = 0x0800;

p4src/settings.p4

@@ -9,5 +9,6 @@
 #define THE_ANSWER_TO_LIFE_THE_UNIVERSE_AND_EVERYTHING 42   /* Important constant          */
 #define ROUTING_TABLE_SIZE 64                               /* maximum routes per protocol */
 #define ADDRESS_TABLE_SIZE 64                               /* maximum number of addresses per protocol */
+#define NDP_TABLE_SIZE 64                                   /* maximum number of multicast groups */
 
 #endif

p4src/static-mapping.p4

@@ -21,6 +21,26 @@ control MyIngress(inout headers hdr,
         clone3(CloneType.I2E, 100, meta);
     }
 
+    /********************** NDP support ***********************************/
+
+    /* map port to group */
+    action multicast_pkg(mcast_t mcast_grp) {
+        standard_metadata.mcast_grp = mcast_grp;
+    }
+
+    table ndp {
+        key = {
+            hdr.ipv6.dst_addr: lpm;
+            standard_metadata.ingress_port : exact;
+        }
+        actions = {
+			multicast_pkg;
+            NoAction;
+        }
+        size = NDP_TABLE_SIZE;
+        default_action = NoAction;
+    }
+
 
     /********************** ADDRESS TABLES ***********************************/
     action icmp6_answer() {