tap: add support for persistance

Type: feature

Change-Id: I775f53531972447ebae0d69b9e2dfeee84d115e5
Signed-off-by: Mohsin Kazmi <sykazmi@cisco.com>

1 files changed, 101 insertions, 36 deletions

diff --git a/src/vnet/devices/tap/tap.c b/src/vnet/devices/tap/tap.c
index 6f16a4cd71d..e17d01d88b1 100644
--- a/src/vnet/devices/tap/tap.c
+++ b/src/vnet/devices/tap/tap.c
@@ -91,6 +91,7 @@ tap_free (vlib_main_t * vm, virtio_if_t * vif)
 {
   virtio_main_t *mm = &virtio_main;
   tap_main_t *tm = &tap_main;
+  clib_error_t *err = 0;
   int i;
 
   /* *INDENT-OFF* */
@@ -102,6 +103,9 @@ tap_free (vlib_main_t * vm, virtio_if_t * vif)
     virtio_vring_free_tx (vm, vif, TX_QUEUE (i));
   /* *INDENT-ON* */
 
+  _IOCTL (vif->tap_fd, TUNSETPERSIST, (void *) (uintptr_t) 0);
+  tap_log_dbg (vif, "TUNSETPERSIST: unset");
+error:
   if (vif->tap_fd != -1)
     close (vif->tap_fd);
 
@@ -131,6 +135,7 @@ tap_create_if (vlib_main_t * vm, tap_create_if_args_t * args)
   int i;
   int old_netns_fd = -1;
   struct ifreq ifr = {.ifr_flags = IFF_TAP | IFF_NO_PI | IFF_VNET_HDR };
+  struct ifreq get_ifr = {.ifr_flags = 0 };
   size_t hdrsz;
   struct vhost_memory *vhost_mem = 0;
   virtio_if_t *vif = 0;
@@ -170,6 +175,39 @@ tap_create_if (vlib_main_t * vm, tap_create_if_args_t * args)
   vif->num_rxqs = args->num_rx_queues;
   num_q_pairs = clib_max (vif->num_rxqs, vif->num_txqs);
 
+  if (args->tap_flags & TAP_FLAG_ATTACH)
+    {
+      if (args->host_if_name != NULL)
+	{
+	  host_if_name = (char *) args->host_if_name;
+	  clib_memcpy (ifr.ifr_name, host_if_name,
+		       clib_min (IFNAMSIZ, strlen (host_if_name)));
+	}
+      else
+	{
+	  args->rv = VNET_API_ERROR_NO_MATCHING_INTERFACE;
+	  err = clib_error_return (0, "host_if_name is not provided");
+	  goto error;
+	}
+      if (args->host_namespace)
+	{
+	  old_netns_fd = open ("/proc/self/ns/net", O_RDONLY);
+	  if ((nfd = open_netns_fd ((char *) args->host_namespace)) == -1)
+	    {
+	      args->rv = VNET_API_ERROR_SYSCALL_ERROR_2;
+	      args->error = clib_error_return_unix (0, "open_netns_fd '%s'",
+						    args->host_namespace);
+	      goto error;
+	    }
+	  if (setns (nfd, CLONE_NEWNET) == -1)
+	    {
+	      args->rv = VNET_API_ERROR_SYSCALL_ERROR_3;
+	      args->error = clib_error_return_unix (0, "setns '%s'",
+						    args->host_namespace);
+	      goto error;
+	    }
+	}
+    }
   if ((vif->tap_fd = tfd = open ("/dev/net/tun", O_RDWR | O_NONBLOCK)) < 0)
     {
       args->rv = VNET_API_ERROR_SYSCALL_ERROR_2;
@@ -231,6 +269,33 @@ tap_create_if (vlib_main_t * vm, tap_create_if_args_t * args)
       goto error;
     }
 
+  /*
+   * unset the persistence when attaching to existing
+   * interface
+   */
+  if (args->tap_flags & TAP_FLAG_ATTACH)
+    {
+      _IOCTL (tfd, TUNSETPERSIST, (void *) (uintptr_t) 0);
+      tap_log_dbg (vif, "TUNSETPERSIST: unset");
+    }
+
+  /* set the persistence */
+  if (args->tap_flags & TAP_FLAG_PERSIST)
+    {
+      _IOCTL (tfd, TUNSETPERSIST, (void *) (uintptr_t) 1);
+      tap_log_dbg (vif, "TUNSETPERSIST: set");
+
+      /* verify persistence is set, read the flags */
+      _IOCTL (tfd, TUNGETIFF, (void *) &get_ifr);
+      tap_log_dbg (vif, "TUNGETIFF: flags 0x%lx", get_ifr.ifr_flags);
+      if ((get_ifr.ifr_flags & IFF_PERSIST) == 0)
+	{
+	  args->rv = VNET_API_ERROR_SYSCALL_ERROR_2;
+	  args->error = clib_error_return (0, "persistence not supported");
+	  goto error;
+	}
+    }
+
   tap_log_dbg (vif, "TUNSETVNETHDRSZ: fd %d vnet_hdr_sz %u", tfd, hdrsz);
   _IOCTL (tfd, TUNSETVNETHDRSZ, &hdrsz);
 
@@ -291,46 +356,46 @@ tap_create_if (vlib_main_t * vm, tap_create_if_args_t * args)
 
   virtio_set_net_hdr_size (vif);
 
-  /* if namespace is specified, all further netlink messages should be executed
-     after we change our net namespace */
-  if (args->host_namespace)
+  if (!(args->tap_flags & TAP_FLAG_ATTACH))
     {
-      old_netns_fd = open ("/proc/self/ns/net", O_RDONLY);
-      if ((nfd = open_netns_fd ((char *) args->host_namespace)) == -1)
+      /* if namespace is specified, all further netlink messages should be executed
+         after we change our net namespace */
+      if (args->host_namespace)
 	{
-	  args->rv = VNET_API_ERROR_SYSCALL_ERROR_2;
-	  args->error = clib_error_return_unix (0, "open_netns_fd '%s'",
-						args->host_namespace);
-	  goto error;
-	}
-      args->error = vnet_netlink_set_link_netns (vif->ifindex, nfd,
-						 host_if_name);
-      if (args->error)
-	{
-	  args->rv = VNET_API_ERROR_NETLINK_ERROR;
-	  goto error;
-	}
-      if (setns (nfd, CLONE_NEWNET) == -1)
-	{
-	  args->rv = VNET_API_ERROR_SYSCALL_ERROR_3;
-	  args->error = clib_error_return_unix (0, "setns '%s'",
-						args->host_namespace);
-	  goto error;
-	}
-      if ((vif->ifindex = if_nametoindex (host_if_name)) == 0)
-	{
-	  args->rv = VNET_API_ERROR_SYSCALL_ERROR_3;
-	  args->error = clib_error_return_unix (0, "if_nametoindex '%s'",
-						host_if_name);
-	  goto error;
+	  old_netns_fd = open ("/proc/self/ns/net", O_RDONLY);
+	  if ((nfd = open_netns_fd ((char *) args->host_namespace)) == -1)
+	    {
+	      args->rv = VNET_API_ERROR_SYSCALL_ERROR_2;
+	      args->error = clib_error_return_unix (0, "open_netns_fd '%s'",
+						    args->host_namespace);
+	      goto error;
+	    }
+	  args->error = vnet_netlink_set_link_netns (vif->ifindex, nfd,
+						     host_if_name);
+	  if (args->error)
+	    {
+	      args->rv = VNET_API_ERROR_NETLINK_ERROR;
+	      goto error;
+	    }
+	  if (setns (nfd, CLONE_NEWNET) == -1)
+	    {
+	      args->rv = VNET_API_ERROR_SYSCALL_ERROR_3;
+	      args->error = clib_error_return_unix (0, "setns '%s'",
+						    args->host_namespace);
+	      goto error;
+	    }
+	  if ((vif->ifindex = if_nametoindex (host_if_name)) == 0)
+	    {
+	      args->rv = VNET_API_ERROR_SYSCALL_ERROR_3;
+	      args->error = clib_error_return_unix (0, "if_nametoindex '%s'",
+						    host_if_name);
+	      goto error;
+	    }
 	}
-    }
-  else
-    {
-      if (host_if_name)
+      else if (host_if_name)
 	{
-	  args->error = vnet_netlink_set_link_name (vif->ifindex,
-						    host_if_name);
+	  args->error =
+	    vnet_netlink_set_link_name (vif->ifindex, host_if_name);
 	  if (args->error)
 	    {
 	      args->rv = VNET_API_ERROR_NETLINK_ERROR;