IP Multicast FIB (mfib)

 - IPv[46] mfib tables with support for (*,G/m), (*,G) and (S,G) exact and longest prefix match
 - Replication represented via a new replicate DPO.
 - RPF configuration and data-plane checking
 - data-plane signals sent to listening control planes.

The functions of multicast forwarding entries differ from their unicast conterparts, so we introduce a new mfib_table_t and mfib_entry_t objects. However, we re-use the fib_path_list to resolve and build the entry's output list. the fib_path_list provides the service to construct a replicate DPO for multicast.

'make tests' is added to with two new suites; TEST=mfib, this is invocation of the CLI command 'test mfib' which deals with many path add/remove, flag set/unset scenarios, TEST=ip-mcast, data-plane forwarding tests.

Updated applications to use the new MIFB functions;
  - IPv6 NS/RA.
  - DHCPv6
 unit tests for these are undated accordingly.

Change-Id: I49ec37b01f1b170335a5697541c8fd30e6d3a961
Signed-off-by: Neale Ranns <nranns@cisco.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/src/vnet/rewrite.h b/src/vnet/rewrite.h
index 00c1efbdc5e..ce2bce3a3c8 100644
--- a/src/vnet/rewrite.h
+++ b/src/vnet/rewrite.h
@@ -64,6 +64,16 @@ typedef CLIB_PACKED (struct {
      Used for MTU check after packet rewrite. */
   u16 max_l3_packet_bytes;
 
+  /* When dynamically writing a multicast destination L2 addresss
+   * this is the offset within the address to start writing n
+   * bytes of the IP mcast address */
+  u8 dst_mcast_offset;
+
+  /* When dynamically writing a multicast destination L2 addresss
+   * this is the number of bytes of the dest IP address to write into
+   * the MAC rewrite */
+  u8 dst_mcast_n_bytes;
+
   /* Rewrite string starting at end and going backwards. */
   u8 data[0];
 }) vnet_rewrite_header_t;
@@ -261,6 +271,27 @@ _vnet_rewrite_two_headers (vnet_rewrite_header_t * h0,
 			     sizeof ((rw0).rewrite_data),		\
 			     (most_likely_size))
 
+always_inline void
+_vnet_fixup_one_header (vnet_rewrite_header_t * h0,
+			u8 * addr, u32 addr_len,
+			u8 * packet0, int clear_first_bit)
+{
+  /* location to write to in the packet */
+  u8 *p0 = packet0 - h0->dst_mcast_offset;
+  u8 *p1 = p0;
+  /* location to write from in the L3 dest address */
+  u8 *a0 = addr + addr_len - h0->dst_mcast_n_bytes;
+
+  clib_memcpy (p0, a0, h0->dst_mcast_n_bytes);
+  if (clear_first_bit)
+    *p1 &= 0x7f;
+}
+
+#define vnet_fixup_one_header(rw0,addr,p0,clear_first_bit)              \
+  _vnet_fixup_one_header (&((rw0).rewrite_header),                      \
+                          (u8*)(addr), sizeof((*addr)),                 \
+                          (u8*)(p0), (clear_first_bit))
+
 #define VNET_REWRITE_FOR_SW_INTERFACE_ADDRESS_BROADCAST ((void *) 0)
 /** Deprecated */
 void vnet_rewrite_for_sw_interface (struct vnet_main_t *vnm,