MTU: Software interface / Per-protocol MTU support

This patch separates setting of hardware interfaec and software
interface MTU. Software MTU is L2 payload MTU (i.e. not including L2
header). Per-protocol MTU for IPv4, IPv6 and MPLS can also be set.
Currently only IP4, IP6 are enabled in adjacency / rewrite code.

Documentation in src/vnet/MTU.md

Change-Id: Iee2fd6f0bbc8210748dd8e073ab9fab87d323690
Signed-off-by: Ole Troan <ot@cisco.com>

7 files changed, 18 insertions, 37 deletions

diff --git a/src/vnet/adj/adj.c b/src/vnet/adj/adj.c
index abfe8729b39..0de3fc8b775 100644
--- a/src/vnet/adj/adj.c
+++ b/src/vnet/adj/adj.c
@@ -347,36 +347,19 @@ adj_mtu_update_walk_cb (adj_index_t ai,
 
     adj = adj_get(ai);
 
-    vnet_rewrite_update_mtu (vnet_get_main(),
+    vnet_rewrite_update_mtu (vnet_get_main(), adj->ia_link,
                              &adj->rewrite_header);
 
     return (ADJ_WALK_RC_CONTINUE);
 }
 
-static walk_rc_t
-adj_sw_mtu_update (vnet_main_t * vnm,
-                   u32 sw_if_index,
-                   void *ctx)
+static void
+adj_mtu_update (vnet_main_t * vnm, u32 sw_if_index, u32 flags)
 {
-    /*
-     * Walk all the adjacencies on the interface to update the cached MTU
-     */
-    adj_walk (sw_if_index, adj_mtu_update_walk_cb, NULL);
-
-    return (WALK_CONTINUE);
+  adj_walk (sw_if_index, adj_mtu_update_walk_cb, NULL);
 }
 
-void
-adj_mtu_update (u32 hw_if_index)
-{
-    /*
-     * Walk all the SW interfaces on the HW interface to update the cached MTU
-     */
-    vnet_hw_interface_walk_sw(vnet_get_main(),
-                              hw_if_index,
-                              adj_sw_mtu_update,
-                              NULL);
-}
+VNET_SW_INTERFACE_MTU_CHANGE_FUNCTION(adj_mtu_update);
 
 /**
  * @brief Walk the Adjacencies on a given interface
diff --git a/src/vnet/adj/adj.h b/src/vnet/adj/adj.h
index bcf6c041209..fe77d1634e0 100644
--- a/src/vnet/adj/adj.h
+++ b/src/vnet/adj/adj.h
@@ -345,12 +345,6 @@ extern const u8* adj_get_rewrite (adj_index_t ai);
 extern void adj_feature_update (u32 sw_if_index, u8 arc_index, u8 is_enable);
 
 /**
- * @brief Notify the adjacency subsystem that the MTU settings for
- * an HW interface have changed
- */
-extern void adj_mtu_update (u32 hw_if_index);
-
-/**
  * @brief
  * The global adjacnecy pool. Exposed for fast/inline data-plane access
  */
diff --git a/src/vnet/adj/adj_glean.c b/src/vnet/adj/adj_glean.c
index 74881d7f67c..92369116532 100644
--- a/src/vnet/adj/adj_glean.c
+++ b/src/vnet/adj/adj_glean.c
@@ -77,8 +77,8 @@ adj_glean_add_or_lock (fib_protocol_t proto,
 	adj->rewrite_header.sw_if_index = sw_if_index;
 	adj->rewrite_header.data_bytes = 0;
         adj->rewrite_header.max_l3_packet_bytes =
-            vnet_sw_interface_get_mtu(vnet_get_main(), sw_if_index, VLIB_TX);
-
+	  vnet_sw_interface_get_mtu(vnet_get_main(), sw_if_index,
+                                    vnet_link_to_mtu(linkt));
         adj_lock(adj_get_index(adj));
 
 	vnet_update_adjacency_for_sw_interface(vnet_get_main(),
diff --git a/src/vnet/adj/adj_mcast.c b/src/vnet/adj/adj_mcast.c
index 593c1b66a8a..9fbad482600 100644
--- a/src/vnet/adj/adj_mcast.c
+++ b/src/vnet/adj/adj_mcast.c
@@ -69,7 +69,7 @@ adj_mcast_add_or_lock (fib_protocol_t proto,
 	adj_mcasts[proto][sw_if_index] = adj_get_index(adj);
         adj_lock(adj_get_index(adj));
 
-	vnet_rewrite_init(vnm, sw_if_index,
+	vnet_rewrite_init(vnm, sw_if_index, link_type,
 			  adj_get_mcast_node(proto),
 			  vnet_tx_node_index_for_sw_interface(vnm, sw_if_index),
 			  &adj->rewrite_header);
diff --git a/src/vnet/adj/adj_nbr.c b/src/vnet/adj/adj_nbr.c
index 6fd9b40efc3..3f66acbb5c5 100644
--- a/src/vnet/adj/adj_nbr.c
+++ b/src/vnet/adj/adj_nbr.c
@@ -230,7 +230,7 @@ adj_nbr_add_or_lock (fib_protocol_t nh_proto,
 	adj_index = adj_get_index(adj);
 	adj_lock(adj_index);
 
-	vnet_rewrite_init(vnm, sw_if_index,
+	vnet_rewrite_init(vnm, sw_if_index, link_type,
 			  adj_get_nd_node(nh_proto),
 			  vnet_tx_node_index_for_sw_interface(vnm, sw_if_index),
 			  &adj->rewrite_header);
diff --git a/src/vnet/adj/rewrite.c b/src/vnet/adj/rewrite.c
index f4b26a9d0dd..1a87793eb1c 100644
--- a/src/vnet/adj/rewrite.c
+++ b/src/vnet/adj/rewrite.c
@@ -103,19 +103,22 @@ vnet_tx_node_index_for_sw_interface (vnet_main_t * vnm, u32 sw_if_index)
 void
 vnet_rewrite_init (vnet_main_t * vnm,
 		   u32 sw_if_index,
+		   vnet_link_t linkt,
 		   u32 this_node, u32 next_node, vnet_rewrite_header_t * rw)
 {
   rw->sw_if_index = sw_if_index;
   rw->next_index = vlib_node_add_next (vnm->vlib_main, this_node, next_node);
   rw->max_l3_packet_bytes =
-    vnet_sw_interface_get_mtu (vnm, sw_if_index, VLIB_TX);
+    vnet_sw_interface_get_mtu (vnm, sw_if_index, vnet_link_to_mtu (linkt));
 }
 
 void
-vnet_rewrite_update_mtu (vnet_main_t * vnm, vnet_rewrite_header_t * rw)
+vnet_rewrite_update_mtu (vnet_main_t * vnm, vnet_link_t linkt,
+			 vnet_rewrite_header_t * rw)
 {
   rw->max_l3_packet_bytes =
-    vnet_sw_interface_get_mtu (vnm, rw->sw_if_index, VLIB_TX);
+    vnet_sw_interface_get_mtu (vnm, rw->sw_if_index,
+			       vnet_link_to_mtu (linkt));
 }
 
 void
@@ -133,7 +136,7 @@ vnet_rewrite_for_sw_interface (vnet_main_t * vnm,
     vnet_get_hw_interface_class (vnm, hw->hw_class_index);
   u8 *rewrite = NULL;
 
-  vnet_rewrite_init (vnm, sw_if_index, node_index,
+  vnet_rewrite_init (vnm, sw_if_index, link_type, node_index,
 		     vnet_tx_node_index_for_sw_interface (vnm, sw_if_index),
 		     rw);
 
diff --git a/src/vnet/adj/rewrite.h b/src/vnet/adj/rewrite.h
index 712f686f4ae..0d4b0b9fd28 100644
--- a/src/vnet/adj/rewrite.h
+++ b/src/vnet/adj/rewrite.h
@@ -314,11 +314,12 @@ u32 vnet_tx_node_index_for_sw_interface (struct vnet_main_t *vnm,
 
 void vnet_rewrite_init (struct vnet_main_t *vnm,
 			u32 sw_if_index,
+			vnet_link_t linkt,
 			u32 this_node,
 			u32 next_node, vnet_rewrite_header_t * rw);
 
 void vnet_rewrite_update_mtu (struct vnet_main_t *vnm,
-			      vnet_rewrite_header_t * rw);
+			      vnet_link_t linkt, vnet_rewrite_header_t * rw);
 
 u8 *vnet_build_rewrite_for_sw_interface (struct vnet_main_t *vnm,
 					 u32 sw_if_index,