interface: improve MTU handling

 - per hw-interface-class handlers
 - ethernet set_mtu callback
 - driver can now refuse MTU change

Type: improvement
Change-Id: I3d37c9129930ebec7bb70caf4263025413873048
Signed-off-by: Damjan Marion <damarion@cisco.com>

2 files changed, 19 insertions, 7 deletions

diff --git a/src/vnet/ethernet/ethernet.h b/src/vnet/ethernet/ethernet.h
index 9621429e4ee..b6adeb6f44d 100644
--- a/src/vnet/ethernet/ethernet.h
+++ b/src/vnet/ethernet/ethernet.h
@@ -130,7 +130,11 @@ typedef u32 (ethernet_flag_change_function_t)
 
 typedef struct
 {
+  /* ethernet interface flags change */
   ethernet_flag_change_function_t *flag_change;
+
+  /* set MTU callback */
+  vnet_interface_set_mtu_function_t *set_mtu;
 } vnet_eth_if_callbacks_t;
 
 #define ETHERNET_MIN_PACKET_BYTES  64
@@ -166,9 +170,6 @@ typedef struct ethernet_interface
   /* Set interface to accept all packets (promiscuous mode). */
 #define ETHERNET_INTERFACE_FLAG_ACCEPT_ALL 1
 
-  /* Change MTU on interface from hw interface structure */
-#define ETHERNET_INTERFACE_FLAG_MTU        2
-
   /* Callback, e.g. to turn on/off promiscuous mode */
   vnet_eth_if_callbacks_t cb;
 
diff --git a/src/vnet/ethernet/interface.c b/src/vnet/ethernet/interface.c
index b1513a79774..bac882228cb 100644
--- a/src/vnet/ethernet/interface.c
+++ b/src/vnet/ethernet/interface.c
@@ -310,6 +310,18 @@ ethernet_mac_change (vnet_hw_interface_t * hi,
   return (NULL);
 }
 
+static clib_error_t *
+ethernet_set_mtu (vnet_main_t *vnm, vnet_hw_interface_t *hi, u32 mtu)
+{
+  ethernet_interface_t *ei =
+    pool_elt_at_index (ethernet_main.interfaces, hi->hw_instance);
+
+  if (ei->cb.set_mtu)
+    return ei->cb.set_mtu (vnm, hi, mtu);
+
+  return 0;
+}
+
 /* *INDENT-OFF* */
 VNET_HW_INTERFACE_CLASS (ethernet_hw_interface_class) = {
   .name = "Ethernet",
@@ -321,6 +333,7 @@ VNET_HW_INTERFACE_CLASS (ethernet_hw_interface_class) = {
   .build_rewrite = ethernet_build_rewrite,
   .update_adjacency = ethernet_update_adjacency,
   .mac_addr_change_function = ethernet_mac_change,
+  .set_mtu = ethernet_set_mtu,
 };
 /* *INDENT-ON* */
 
@@ -367,8 +380,8 @@ vnet_eth_register_interface (vnet_main_t *vnm,
 
   hi->min_packet_bytes = hi->min_supported_packet_bytes =
     ETHERNET_MIN_PACKET_BYTES;
-  hi->max_packet_bytes = hi->max_supported_packet_bytes =
-    ETHERNET_MAX_PACKET_BYTES;
+  hi->max_supported_packet_bytes = ETHERNET_MAX_PACKET_BYTES;
+  hi->max_packet_bytes = em->default_mtu;
 
   /* Default ethernet MTU, 9000 unless set by ethernet_config see below */
   vnet_sw_interface_set_mtu (vnm, hi->sw_if_index, em->default_mtu);
@@ -460,8 +473,6 @@ ethernet_set_flags (vnet_main_t * vnm, u32 hw_if_index, u32 flags)
 	  /* fall through */
 	case ETHERNET_INTERFACE_FLAG_ACCEPT_ALL:
 	  ei->flags &= ~ETHERNET_INTERFACE_FLAG_STATUS_L3;
-	  /* fall through */
-	case ETHERNET_INTERFACE_FLAG_MTU:
 	  return ei->cb.flag_change (vnm, hi, opn_flags);
 	default:
 	  return ~0;