Mcast rewrite optimisations

hard code the address mask offsets. This are protocol specific and only used on ethernet when used at all.

Change-Id: Ib1f6f33682f53254ffbb5a241a1583e65420e0c7
Signed-off-by: Neale Ranns <nranns@cisco.com>

3 files changed, 8 insertions, 33 deletions

diff --git a/src/vnet/adj/adj_mcast.c b/src/vnet/adj/adj_mcast.c
index efc781de989..deaa7fcffa4 100644
--- a/src/vnet/adj/adj_mcast.c
+++ b/src/vnet/adj/adj_mcast.c
@@ -101,8 +101,7 @@ adj_mcast_add_or_lock (fib_protocol_t proto,
 void
 adj_mcast_update_rewrite (adj_index_t adj_index,
                           u8 *rewrite,
-                          u8 offset,
-                          u32 mask)
+                          u8 offset)
 {
     ip_adjacency_t *adj;
 
@@ -121,12 +120,9 @@ adj_mcast_update_rewrite (adj_index_t adj_index,
                                         adj->rewrite_header.sw_if_index),
                                     rewrite);
     /*
-     * set the fields corresponding to the mcast IP address rewrite
-     * The mask must be stored in network byte order, since the packet's
-     * IP address will also be in network order.
+     * set the offset corresponding to the mcast IP address rewrite
      */
     adj->rewrite_header.dst_mcast_offset = offset;
-    adj->rewrite_header.dst_mcast_mask = clib_host_to_net_u32(mask);
 }
 
 /**
@@ -174,13 +170,7 @@ adj_mcast_midchain_update_rewrite (adj_index_t adj_index,
                                         adj->rewrite_header.sw_if_index),
                                     rewrite);
 
-    /*
-     * set the fields corresponding to the mcast IP address rewrite
-     * The mask must be stored in network byte order, since the packet's
-     * IP address will also be in network order.
-     */
     adj->rewrite_header.dst_mcast_offset = offset;
-    adj->rewrite_header.dst_mcast_mask = clib_host_to_net_u32(mask);
 }
 
 void
diff --git a/src/vnet/adj/adj_mcast.h b/src/vnet/adj/adj_mcast.h
index 55e2ec03d09..286901d24a1 100644
--- a/src/vnet/adj/adj_mcast.h
+++ b/src/vnet/adj/adj_mcast.h
@@ -60,14 +60,10 @@ extern adj_index_t adj_mcast_add_or_lock(fib_protocol_t proto,
  * @param
  *  The offset in the rewrite a which to write in packet's
  *  IP Address
- *
- * @param
- *  The mask to apply to the packet berfore the rewrite.
  */
 extern void adj_mcast_update_rewrite(adj_index_t adj_index,
                                      u8 *rewrite,
-                                     u8 offset,
-                                     u32 mask);
+                                     u8 offset);
 
 /**
  * @brief
diff --git a/src/vnet/adj/rewrite.h b/src/vnet/adj/rewrite.h
index 005ac41fe72..712f686f4ae 100644
--- a/src/vnet/adj/rewrite.h
+++ b/src/vnet/adj/rewrite.h
@@ -81,10 +81,6 @@ typedef CLIB_PACKED (struct {
    */
   u8 dst_mcast_offset;
 
-  /* The mask to apply to the lower 4 bytes of the IP address before ORing
-   * into the destinaiton MAC address */
-  u32 dst_mcast_mask;
-
   /* Rewrite string starting at end and going backwards. */
   u8 data[0];
 }) vnet_rewrite_header_t;
@@ -290,26 +286,19 @@ _vnet_rewrite_two_headers (vnet_rewrite_header_t * h0,
 			     (most_likely_size))
 
 always_inline void
-_vnet_fixup_one_header (vnet_rewrite_header_t * h0,
-			u8 * addr, u32 addr_len, u8 * packet0)
+vnet_ip_mcast_fixup_header (u32 dst_mcast_mask,
+			    u32 dst_mcast_offset, u32 * addr, u8 * packet0)
 {
-  if (PREDICT_TRUE (h0->dst_mcast_mask))
+  if (PREDICT_TRUE (0 != dst_mcast_offset))
     {
       /* location to write to in the packet */
-      u8 *p0 = packet0 - h0->dst_mcast_offset;
+      u8 *p0 = packet0 - dst_mcast_offset;
       u32 *p1 = (u32 *) p0;
-      /* location to copy from in the L3 dest address */
-      u32 *a0 = (u32 *) (addr + addr_len - sizeof (h0->dst_mcast_mask));
 
-      *p1 |= (*a0 & h0->dst_mcast_mask);
+      *p1 |= (*addr & dst_mcast_mask);
     }
 }
 
-#define vnet_fixup_one_header(rw0,addr,p0)              \
-  _vnet_fixup_one_header (&((rw0).rewrite_header),                      \
-                          (u8*)(addr), sizeof((*addr)),                 \
-                          (u8*)(p0))
-
 #define VNET_REWRITE_FOR_SW_INTERFACE_ADDRESS_BROADCAST ((void *) 0)
 /** Deprecated */
 void vnet_rewrite_for_sw_interface (struct vnet_main_t *vnm,