fib: midchain adjacency optimisations

Type: improvement

 - inline some common encap fixup functions into the midchain
   rewrite node so we don't incur the cost of the virtual function call
 - change the copy 'guess' from ethernet_header (which will never happen) to an ip4 header
 - add adj-midchain-tx to multiarch sources
 - don't run adj-midchain-tx as a feature, instead put this node as the
   adj's next and at the end of the feature arc.
 - cache the feature arc config index (to save the cache miss going to fetch it)
 - don't check if features are enabled when taking the arc (since we know they are)

the last two changes will also benefit normal adjacencies taking the arc (i.e. for NAT, ACLs, etc)

for IPSec:
 - don't run esp_encrypt as a feature, instead when required insert this
   node into the adj's next and into the end of the feature arc. this
   implies that encrypt is always 'the last feature' run, which is
   symmetric with decrypt always being the first.
 - esp_encrpyt for tunnels has adj-midchain-tx as next node

Change-Id: Ida0af56a704302cf2d7797ded5f118a781e8acb7
Signed-off-by: Neale Ranns <nranns@cisco.com>

1 files changed, 27 insertions, 11 deletions

diff --git a/src/vnet/ipip/ipip.c b/src/vnet/ipip/ipip.c
index 047a2df811e..089e2b659c7 100644
--- a/src/vnet/ipip/ipip.c
+++ b/src/vnet/ipip/ipip.c
@@ -84,7 +84,6 @@ ipip_build_rewrite (vnet_main_t * vnm, u32 sw_if_index,
 	ip4_header_set_dscp (ip4, t->dscp);
       if (t->flags & TUNNEL_ENCAP_DECAP_FLAG_ENCAP_SET_DF)
 	ip4_header_set_df (ip4);
-      ip4->checksum = ip4_header_checksum (ip4);
 
       switch (link_type)
 	{
@@ -97,6 +96,7 @@ ipip_build_rewrite (vnet_main_t * vnm, u32 sw_if_index,
 	default:
 	  break;
 	}
+      ip4->checksum = ip4_header_checksum (ip4);
       break;
 
     case IPIP_TRANSPORT_IP6:
@@ -259,7 +259,7 @@ ipip_tunnel_restack (ipip_tunnel_t * gt)
 }
 
 static adj_midchain_fixup_t
-ipip_get_fixup (const ipip_tunnel_t * t, vnet_link_t lt)
+ipip_get_fixup (const ipip_tunnel_t * t, vnet_link_t lt, adj_flags_t * aflags)
 {
   if (t->transport == IPIP_TRANSPORT_IP6 && lt == VNET_LINK_IP6)
     return (ipip66_fixup);
@@ -268,7 +268,10 @@ ipip_get_fixup (const ipip_tunnel_t * t, vnet_link_t lt)
   if (t->transport == IPIP_TRANSPORT_IP4 && lt == VNET_LINK_IP6)
     return (ipip64_fixup);
   if (t->transport == IPIP_TRANSPORT_IP4 && lt == VNET_LINK_IP4)
-    return (ipip44_fixup);
+    {
+      *aflags = *aflags | ADJ_FLAG_MIDCHAIN_FIXUP_IP4O4_HDR;
+      return (ipip44_fixup);
+    }
 
   ASSERT (0);
   return (ipip44_fixup);
@@ -277,6 +280,7 @@ ipip_get_fixup (const ipip_tunnel_t * t, vnet_link_t lt)
 void
 ipip_update_adj (vnet_main_t * vnm, u32 sw_if_index, adj_index_t ai)
 {
+  adj_midchain_fixup_t fixup;
   ipip_tunnel_t *t;
   adj_flags_t af;
 
@@ -288,8 +292,9 @@ ipip_update_adj (vnet_main_t * vnm, u32 sw_if_index, adj_index_t ai)
   if (VNET_LINK_ETHERNET == adj_get_link_type (ai))
     af |= ADJ_FLAG_MIDCHAIN_NO_COUNT;
 
+  fixup = ipip_get_fixup (t, adj_get_link_type (ai), &af);
   adj_nbr_midchain_update_rewrite
-    (ai, ipip_get_fixup (t, adj_get_link_type (ai)),
+    (ai, fixup,
      uword_to_pointer (t->flags, void *), af,
      ipip_build_rewrite (vnm, sw_if_index,
 			 adj_get_link_type (ai), &t->tunnel_dst));
@@ -305,10 +310,15 @@ typedef struct mipip_walk_ctx_t_
 static adj_walk_rc_t
 mipip_mk_complete_walk (adj_index_t ai, void *data)
 {
+  adj_midchain_fixup_t fixup;
   mipip_walk_ctx_t *ctx = data;
+  adj_flags_t af;
+
+  af = ADJ_FLAG_NONE;
+  fixup = ipip_get_fixup (ctx->t, adj_get_link_type (ai), &af);
 
   adj_nbr_midchain_update_rewrite
-    (ai, ipip_get_fixup (ctx->t, adj_get_link_type (ai)),
+    (ai, fixup,
      uword_to_pointer (ctx->t->flags, void *),
      ADJ_FLAG_MIDCHAIN_IP_STACK, ipip_build_rewrite (vnet_get_main (),
 						     ctx->t->sw_if_index,
@@ -324,11 +334,14 @@ mipip_mk_complete_walk (adj_index_t ai, void *data)
 static adj_walk_rc_t
 mipip_mk_incomplete_walk (adj_index_t ai, void *data)
 {
+  adj_midchain_fixup_t fixup;
   ipip_tunnel_t *t = data;
+  adj_flags_t af;
 
-  adj_nbr_midchain_update_rewrite
-    (ai, ipip_get_fixup (t, adj_get_link_type (ai)),
-     NULL, ADJ_FLAG_NONE, NULL);
+  af = ADJ_FLAG_NONE;
+  fixup = ipip_get_fixup (t, adj_get_link_type (ai), &af);
+
+  adj_nbr_midchain_update_rewrite (ai, fixup, NULL, ADJ_FLAG_NONE, NULL);
 
   adj_midchain_delegate_unstack (ai);
 
@@ -339,11 +352,14 @@ void
 mipip_update_adj (vnet_main_t * vnm, u32 sw_if_index, adj_index_t ai)
 {
   ipip_main_t *gm = &ipip_main;
+  adj_midchain_fixup_t fixup;
   ip_adjacency_t *adj;
   teib_entry_t *ne;
   ipip_tunnel_t *t;
+  adj_flags_t af;
   u32 ti;
 
+  af = ADJ_FLAG_NONE;
   adj = adj_get (ai);
   ti = gm->tunnel_index_by_sw_if_index[sw_if_index];
   t = pool_elt_at_index (gm->tunnels, ti);
@@ -352,10 +368,10 @@ mipip_update_adj (vnet_main_t * vnm, u32 sw_if_index, adj_index_t ai)
 
   if (NULL == ne)
     {
-      // no NHRP entry to provide the next-hop
+      // no TEIB entry to provide the next-hop
+      fixup = ipip_get_fixup (t, adj_get_link_type (ai), &af);
       adj_nbr_midchain_update_rewrite
-	(ai, ipip_get_fixup (t, adj_get_link_type (ai)),
-	 uword_to_pointer (t->flags, void *), ADJ_FLAG_NONE, NULL);
+	(ai, fixup, uword_to_pointer (t->flags, void *), ADJ_FLAG_NONE, NULL);
       return;
     }