devices: af-packet gso mtu

Type: fix

Set the GSO flag when buffer length exceeds the
linux mtu. Don't listen for mtu changes on linux
side for now.

This also fixes a TX issue, as we only search for
valid frames on tx to the extent of n_left, we might
stay stuck.

Change-Id: Idf0bdd88990254a614962c2f7bc3e0292ccfd61a
Signed-off-by: Nathan Skrzypczak <nathan.skrzypczak@gmail.com>

1 files changed, 25 insertions, 0 deletions

diff --git a/src/vnet/devices/af_packet/af_packet.c b/src/vnet/devices/af_packet/af_packet.c
index ba6bf3d5a46..2cc0cc70bca 100644
--- a/src/vnet/devices/af_packet/af_packet.c
+++ b/src/vnet/devices/af_packet/af_packet.c
@@ -83,11 +83,32 @@ af_packet_eth_flag_change (vnet_main_t * vnm, vnet_hw_interface_t * hi,
 	  clib_error_free (error);
 	  return VNET_API_ERROR_SYSCALL_ERROR_1;
 	}
+      else
+	apif->host_mtu = hi->max_packet_bytes;
     }
 
   return 0;
 }
 
+static int
+af_packet_read_mtu (af_packet_if_t *apif)
+{
+  af_packet_main_t *apm = &af_packet_main;
+  clib_error_t *error;
+  u8 *s;
+  s = format (0, "/sys/class/net/%s/mtu%c", apif->host_if_name, 0);
+  error = clib_sysfs_read ((char *) s, "%d", &apif->host_mtu);
+  vec_free (s);
+  if (error)
+    {
+      vlib_log_err (apm->log_class, "sysfs read failed to get MTU: %U",
+		    format_clib_error, error);
+      clib_error_free (error);
+      return VNET_API_ERROR_SYSCALL_ERROR_1;
+    }
+  return 0;
+}
+
 static clib_error_t *
 af_packet_fd_read_ready (clib_file_t * uf)
 {
@@ -338,6 +359,10 @@ af_packet_create_if (vlib_main_t * vm, u8 * host_if_name, u8 * hw_addr_set,
   apif->next_tx_frame = 0;
   apif->next_rx_frame = 0;
 
+  ret = af_packet_read_mtu (apif);
+  if (ret != 0)
+    goto error;
+
   if (tm->n_vlib_mains > 1)
     clib_spinlock_init (&apif->lockp);