L2FWD:fix seq_num overwritten + validate l2fib entries when forwarding

l2_classify memeber table_index was overlaid over l2.l2fib_seq_num
which over written when table_index gets initialized in l2_input_classify

solved by overlaying both table_index and opaque_index as only one is used

seperated l2fib seq num from l2_input configs
for better handling of theoretical ABA issue where an entry for a deleted
interface is considered valid by the ager because a different interface with
same sw_if_index and seq_num was created before the ager got a chance to delete

Change-Id: I7b0eeded971627406f1c80834d7e02c0ebe62136
Signed-off-by: Eyal Bari <ebari@cisco.com>
diff --git a/src/vnet/l2/l2_fib.h b/src/vnet/l2/l2_fib.h
index e571a21..0318450 100644
--- a/src/vnet/l2/l2_fib.h
+++ b/src/vnet/l2/l2_fib.h
@@ -27,6 +27,22 @@
 #define L2FIB_NUM_BUCKETS (64 * 1024)
 #define L2FIB_MEMORY_SIZE (256<<20)
 
+typedef struct
+{
+
+  /* hash table */
+  BVT (clib_bihash) mac_table;
+
+  /* per swif vector of sequence number for interface based flush of MACs */
+  u8 *swif_seq_num;
+
+  /* convenience variables */
+  vlib_main_t *vlib_main;
+  vnet_main_t *vnet_main;
+} l2fib_main_t;
+
+extern l2fib_main_t l2fib_main;
+
 /*
  * The L2fib key is the mac address and bridge domain ID
  */
@@ -350,6 +366,14 @@
 
 u8 *format_vnet_sw_if_index_name_with_NA (u8 * s, va_list * args);
 
+static_always_inline u8 *
+l2fib_swif_seq_num (u32 sw_if_index)
+{
+  l2fib_main_t *mp = &l2fib_main;
+  vec_validate (mp->swif_seq_num, sw_if_index);
+  return vec_elt_at_index (mp->swif_seq_num, sw_if_index);
+}
+
 BVT (clib_bihash) * get_mac_table (void);
 
 #endif