wireguard: add peers roaming support

Type: feature

With this change, peers are able to roam between different external
endpoints. Successfully authenticated handshake or data packet that is
received from a new endpoint will cause the peer's endpoint to be
updated accordingly.

Signed-off-by: Alexander Chernavin <achernavin@netgate.com>
Change-Id: Ib4eb7dfa3403f3fb9e8bbe19ba6237c4960c764c

7 files changed, 187 insertions, 49 deletions

diff --git a/src/plugins/wireguard/FEATURE.yaml b/src/plugins/wireguard/FEATURE.yaml
index 4c6946d2a33..5c0a588a484 100644
--- a/src/plugins/wireguard/FEATURE.yaml
+++ b/src/plugins/wireguard/FEATURE.yaml
@@ -7,5 +7,3 @@ features:
 description: "Wireguard protocol implementation"
 state: development
 properties: [API, CLI]
-missing:
-  - Peers roaming between different external IPs
diff --git a/src/plugins/wireguard/README.rst b/src/plugins/wireguard/README.rst
index ead412519b7..35dd2c41382 100644
--- a/src/plugins/wireguard/README.rst
+++ b/src/plugins/wireguard/README.rst
@@ -77,4 +77,3 @@ Main next steps for improving this implementation
 -------------------------------------------------
 
 1. Use all benefits of VPP-engine.
-2. Add peers roaming support
diff --git a/src/plugins/wireguard/wireguard_cli.c b/src/plugins/wireguard/wireguard_cli.c
index 214e6a5e2b4..5fa620507d6 100644
--- a/src/plugins/wireguard/wireguard_cli.c
+++ b/src/plugins/wireguard/wireguard_cli.c
@@ -165,7 +165,7 @@ wg_peer_add_command_fn (vlib_main_t * vm,
   u8 public_key[NOISE_PUBLIC_KEY_LEN + 1];
   fib_prefix_t allowed_ip, *allowed_ips = NULL;
   ip_prefix_t pfx;
-  ip_address_t ip;
+  ip_address_t ip = ip_address_initializer;
   u32 portDst = 0, table_id = 0;
   u32 persistent_keepalive = 0;
   u32 tun_sw_if_index = ~0;
@@ -213,6 +213,12 @@ wg_peer_add_command_fn (vlib_main_t * vm,
 	}
     }
 
+  if (0 == vec_len (allowed_ips))
+    {
+      error = clib_error_return (0, "Allowed IPs are not specified");
+      goto done;
+    }
+
   rv = wg_peer_add (tun_sw_if_index, public_key, table_id, &ip_addr_46 (&ip),
 		    allowed_ips, portDst, persistent_keepalive, &peer_index);
 
diff --git a/src/plugins/wireguard/wireguard_input.c b/src/plugins/wireguard/wireguard_input.c
index b85cdc610e4..22850b832b4 100644
--- a/src/plugins/wireguard/wireguard_input.c
+++ b/src/plugins/wireguard/wireguard_input.c
@@ -125,16 +125,6 @@ typedef enum
   WG_INPUT_N_NEXT,
 } wg_input_next_t;
 
-/* static void */
-/* set_peer_address (wg_peer_t * peer, ip4_address_t ip4, u16 udp_port) */
-/* { */
-/*   if (peer) */
-/*     { */
-/*       ip46_address_set_ip4 (&peer->dst.addr, &ip4); */
-/*       peer->dst.port = udp_port; */
-/*     } */
-/* } */
-
 static u8
 is_ip4_header (u8 *data)
 {
@@ -171,8 +161,8 @@ wg_handshake_process (vlib_main_t *vm, wg_main_t *wmp, vlib_buffer_t *b,
     }
 
   udp_header_t *uhd = current_b_data - sizeof (udp_header_t);
-  u16 udp_src_port = clib_host_to_net_u16 (uhd->src_port);;
-  u16 udp_dst_port = clib_host_to_net_u16 (uhd->dst_port);;
+  u16 udp_src_port = clib_host_to_net_u16 (uhd->src_port);
+  u16 udp_dst_port = clib_host_to_net_u16 (uhd->dst_port);
 
   message_header_t *header = current_b_data;
 
@@ -269,7 +259,8 @@ wg_handshake_process (vlib_main_t *vm, wg_main_t *wmp, vlib_buffer_t *b,
 	    return WG_INPUT_ERROR_PEER;
 	  }
 
-	// set_peer_address (peer, ip4_src, udp_src_port);
+	wg_peer_update_endpoint (rp->r_peer_idx, &src_ip, udp_src_port);
+
 	if (PREDICT_FALSE (!wg_send_handshake_response (vm, peer)))
 	  {
 	    vlib_node_increment_counter (vm, node_idx,
@@ -318,7 +309,8 @@ wg_handshake_process (vlib_main_t *vm, wg_main_t *wmp, vlib_buffer_t *b,
 	    return WG_INPUT_ERROR_PEER;
 	  }
 
-	// set_peer_address (peer, ip4_src, udp_src_port);
+	wg_peer_update_endpoint (peeri, &src_ip, udp_src_port);
+
 	if (noise_remote_begin_session (vm, &peer->remote))
 	  {
 
@@ -582,6 +574,26 @@ error:
   return ret;
 }
 
+static_always_inline void
+wg_find_outer_addr_port (vlib_buffer_t *b, ip46_address_t *addr, u16 *port,
+			 u8 is_ip4)
+{
+  if (is_ip4)
+    {
+      ip4_udp_header_t *ip4_udp_hdr =
+	vlib_buffer_get_current (b) - sizeof (ip4_udp_header_t);
+      ip46_address_set_ip4 (addr, &ip4_udp_hdr->ip4.src_address);
+      *port = clib_net_to_host_u16 (ip4_udp_hdr->udp.src_port);
+    }
+  else
+    {
+      ip6_udp_header_t *ip6_udp_hdr =
+	vlib_buffer_get_current (b) - sizeof (ip6_udp_header_t);
+      ip46_address_set_ip6 (addr, &ip6_udp_hdr->ip6.src_address);
+      *port = clib_net_to_host_u16 (ip6_udp_hdr->udp.src_port);
+    }
+}
+
 always_inline uword
 wg_input_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
 		 vlib_frame_t *frame, u8 is_ip4, u16 async_next_node)
@@ -735,8 +747,6 @@ wg_input_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
 	}
       else
 	{
-	  peer_idx = NULL;
-
 	  /* Handshake packets should be processed in main thread */
 	  if (thread_index != 0)
 	    {
@@ -808,6 +818,10 @@ wg_input_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
 	}
 
       message_data_t *data = vlib_buffer_get_current (b[0]);
+      ip46_address_t out_src_ip;
+      u16 out_udp_src_port;
+
+      wg_find_outer_addr_port (b[0], &out_src_ip, &out_udp_src_port, is_ip4);
 
       if (data->receiver_index != last_rec_idx)
 	{
@@ -823,6 +837,8 @@ wg_input_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
 
       if (PREDICT_FALSE (peer_idx && (last_peer_time_idx != peer_idx)))
 	{
+	  wg_peer_update_endpoint_from_mt (*peer_idx, &out_src_ip,
+					   out_udp_src_port);
 	  wg_timers_any_authenticated_packet_received_opt (peer, time);
 	  wg_timers_any_authenticated_packet_traversal (peer);
 	  last_peer_time_idx = peer_idx;
@@ -890,7 +906,8 @@ wg_input_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
 }
 
 always_inline uword
-wg_input_post (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
+wg_input_post (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame,
+	       u8 is_ip4)
 {
   vnet_main_t *vnm = vnet_get_main ();
   vnet_interface_main_t *im = &vnm->interface_main;
@@ -925,6 +942,10 @@ wg_input_post (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
 
       bool is_keepalive = false;
       message_data_t *data = vlib_buffer_get_current (b[0]);
+      ip46_address_t out_src_ip;
+      u16 out_udp_src_port;
+
+      wg_find_outer_addr_port (b[0], &out_src_ip, &out_udp_src_port, is_ip4);
 
       if (data->receiver_index != last_rec_idx)
 	{
@@ -949,6 +970,8 @@ wg_input_post (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *frame)
 
       if (PREDICT_FALSE (peer_idx && (last_peer_time_idx != peer_idx)))
 	{
+	  wg_peer_update_endpoint_from_mt (*peer_idx, &out_src_ip,
+					   out_udp_src_port);
 	  wg_timers_any_authenticated_packet_received_opt (peer, time);
 	  wg_timers_any_authenticated_packet_traversal (peer);
 	  last_peer_time_idx = peer_idx;
@@ -995,13 +1018,13 @@ VLIB_NODE_FN (wg6_input_node)
 VLIB_NODE_FN (wg4_input_post_node)
 (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame)
 {
-  return wg_input_post (vm, node, from_frame);
+  return wg_input_post (vm, node, from_frame, /* is_ip4 */ 1);
 }
 
 VLIB_NODE_FN (wg6_input_post_node)
 (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame)
 {
-  return wg_input_post (vm, node, from_frame);
+  return wg_input_post (vm, node, from_frame, /* is_ip4 */ 0);
 }
 
 /* *INDENT-OFF* */
diff --git a/src/plugins/wireguard/wireguard_peer.c b/src/plugins/wireguard/wireguard_peer.c
index 589f71272f6..922ca8cdae5 100644
--- a/src/plugins/wireguard/wireguard_peer.c
+++ b/src/plugins/wireguard/wireguard_peer.c
@@ -16,6 +16,7 @@
 
 #include <vnet/adj/adj_midchain.h>
 #include <vnet/fib/fib_table.h>
+#include <vnet/fib/fib_entry_track.h>
 #include <wireguard/wireguard_peer.h>
 #include <wireguard/wireguard_if.h>
 #include <wireguard/wireguard_messages.h>
@@ -63,13 +64,14 @@ wg_peer_clear (vlib_main_t * vm, wg_peer_t * peer)
   wg_peer_endpoint_reset (&peer->src);
   wg_peer_endpoint_reset (&peer->dst);
 
-  adj_index_t *adj_index;
-  vec_foreach (adj_index, peer->adj_indices)
+  wg_peer_adj_t *peer_adj;
+  vec_foreach (peer_adj, peer->adjs)
     {
-      if (INDEX_INVALID != *adj_index)
-	{
-	  wg_peer_by_adj_index[*adj_index] = INDEX_INVALID;
-	}
+      wg_peer_by_adj_index[peer_adj->adj_index] = INDEX_INVALID;
+      if (FIB_NODE_INDEX_INVALID != peer_adj->fib_entry_index)
+	fib_entry_untrack (peer_adj->fib_entry_index, peer_adj->sibling_index);
+      if (adj_is_valid (peer_adj->adj_index))
+	adj_nbr_midchain_unstack (peer_adj->adj_index);
     }
   peer->input_thread_index = ~0;
   peer->output_thread_index = ~0;
@@ -83,8 +85,9 @@ wg_peer_clear (vlib_main_t * vm, wg_peer_t * peer)
   peer->new_handshake_interval_tick = 0;
   peer->rehandshake_interval_tick = 0;
   peer->timer_need_another_keepalive = false;
+  vec_free (peer->rewrite);
   vec_free (peer->allowed_ips);
-  vec_free (peer->adj_indices);
+  vec_free (peer->adjs);
 }
 
 static void
@@ -96,17 +99,17 @@ wg_peer_init (vlib_main_t * vm, wg_peer_t * peer)
 }
 
 static void
-wg_peer_adj_stack (wg_peer_t *peer, adj_index_t ai)
+wg_peer_adj_stack (wg_peer_t *peer, wg_peer_adj_t *peer_adj)
 {
   ip_adjacency_t *adj;
   u32 sw_if_index;
   wg_if_t *wgi;
   fib_protocol_t fib_proto;
 
-  if (!adj_is_valid (ai))
+  if (!adj_is_valid (peer_adj->adj_index))
     return;
 
-  adj = adj_get (ai);
+  adj = adj_get (peer_adj->adj_index);
   sw_if_index = adj->rewrite_header.sw_if_index;
   u8 is_ip4 = ip46_address_is_ip4 (&peer->src.addr);
   fib_proto = is_ip4 ? FIB_PROTOCOL_IP4 : FIB_PROTOCOL_IP6;
@@ -116,9 +119,10 @@ wg_peer_adj_stack (wg_peer_t *peer, adj_index_t ai)
   if (!wgi)
     return;
 
-  if (!vnet_sw_interface_is_admin_up (vnet_get_main (), wgi->sw_if_index))
+  if (!vnet_sw_interface_is_admin_up (vnet_get_main (), wgi->sw_if_index) ||
+      !wg_peer_can_send (peer))
     {
-      adj_midchain_delegate_unstack (ai);
+      adj_nbr_midchain_unstack (peer_adj->adj_index);
     }
   else
     {
@@ -132,8 +136,13 @@ wg_peer_adj_stack (wg_peer_t *peer, adj_index_t ai)
       u32 fib_index;
 
       fib_index = fib_table_find (fib_proto, peer->table_id);
+      peer_adj->fib_entry_index =
+	fib_entry_track (fib_index, &dst, FIB_NODE_TYPE_ADJ,
+			 peer_adj->adj_index, &peer_adj->sibling_index);
 
-      adj_midchain_delegate_stack (ai, fib_index, &dst);
+      adj_nbr_midchain_stack_on_fib_entry (
+	peer_adj->adj_index, peer_adj->fib_entry_index,
+	fib_forw_chain_type_from_fib_proto (dst.fp_proto));
     }
 }
 
@@ -198,11 +207,11 @@ walk_rc_t
 wg_peer_if_admin_state_change (index_t peeri, void *data)
 {
   wg_peer_t *peer;
-  adj_index_t *adj_index;
+  wg_peer_adj_t *peer_adj;
   peer = wg_peer_get (peeri);
-  vec_foreach (adj_index, peer->adj_indices)
+  vec_foreach (peer_adj, peer->adjs)
     {
-      wg_peer_adj_stack (peer, *adj_index);
+      wg_peer_adj_stack (peer, peer_adj);
     }
   return (WALK_CONTINUE);
 }
@@ -215,6 +224,7 @@ wg_peer_if_adj_change (index_t peeri, void *data)
   ip_adjacency_t *adj;
   wg_peer_t *peer;
   fib_prefix_t *allowed_ip;
+  wg_peer_adj_t *peer_adj;
 
   adj = adj_get (*adj_index);
 
@@ -224,17 +234,21 @@ wg_peer_if_adj_change (index_t peeri, void *data)
       if (fib_prefix_is_cover_addr_46 (allowed_ip,
 				       &adj->sub_type.nbr.next_hop))
 	{
-	  vec_add1 (peer->adj_indices, *adj_index);
+	  vec_add2 (peer->adjs, peer_adj, 1);
+	  peer_adj->adj_index = *adj_index;
+	  peer_adj->fib_entry_index = FIB_NODE_INDEX_INVALID;
+	  peer_adj->sibling_index = ~0;
+
 	  vec_validate_init_empty (wg_peer_by_adj_index, *adj_index,
 				   INDEX_INVALID);
-	  wg_peer_by_adj_index[*adj_index] = peer - wg_peer_pool;
+	  wg_peer_by_adj_index[*adj_index] = peeri;
 
 	  fixup = wg_peer_get_fixup (peer, adj_get_link_type (*adj_index));
 	  adj_nbr_midchain_update_rewrite (*adj_index, fixup, NULL,
 					   ADJ_FLAG_MIDCHAIN_IP_STACK,
 					   vec_dup (peer->rewrite));
 
-	  wg_peer_adj_stack (peer, *adj_index);
+	  wg_peer_adj_stack (peer, peer_adj);
 	  return (WALK_STOP);
 	}
     }
@@ -313,6 +327,71 @@ wg_peer_update_flags (index_t peeri, wg_peer_flags flag, bool add_del)
   wg_api_peer_event (peeri, peer->flags);
 }
 
+void
+wg_peer_update_endpoint (index_t peeri, const ip46_address_t *addr, u16 port)
+{
+  wg_peer_t *peer = wg_peer_get (peeri);
+
+  if (ip46_address_is_equal (&peer->dst.addr, addr) && peer->dst.port == port)
+    return;
+
+  wg_peer_endpoint_init (&peer->dst, addr, port);
+
+  u8 is_ip4 = ip46_address_is_ip4 (&peer->dst.addr);
+  vec_free (peer->rewrite);
+  peer->rewrite = wg_build_rewrite (&peer->src.addr, peer->src.port,
+				    &peer->dst.addr, peer->dst.port, is_ip4);
+
+  wg_peer_adj_t *peer_adj;
+  vec_foreach (peer_adj, peer->adjs)
+    {
+      if (FIB_NODE_INDEX_INVALID != peer_adj->fib_entry_index)
+	{
+	  fib_entry_untrack (peer_adj->fib_entry_index,
+			     peer_adj->sibling_index);
+	  peer_adj->fib_entry_index = FIB_NODE_INDEX_INVALID;
+	  peer_adj->sibling_index = ~0;
+	}
+
+      if (adj_is_valid (peer_adj->adj_index))
+	{
+	  adj_midchain_fixup_t fixup =
+	    wg_peer_get_fixup (peer, adj_get_link_type (peer_adj->adj_index));
+	  adj_nbr_midchain_update_rewrite (peer_adj->adj_index, fixup, NULL,
+					   ADJ_FLAG_MIDCHAIN_IP_STACK,
+					   vec_dup (peer->rewrite));
+	  wg_peer_adj_stack (peer, peer_adj);
+	}
+    }
+}
+
+typedef struct wg_peer_upd_ep_args_t_
+{
+  index_t peeri;
+  ip46_address_t addr;
+  u16 port;
+} wg_peer_upd_ep_args_t;
+
+static void
+wg_peer_update_endpoint_thread_fn (wg_peer_upd_ep_args_t *args)
+{
+  wg_peer_update_endpoint (args->peeri, &args->addr, args->port);
+}
+
+void
+wg_peer_update_endpoint_from_mt (index_t peeri, const ip46_address_t *addr,
+				 u16 port)
+{
+  wg_peer_upd_ep_args_t args = {
+    .peeri = peeri,
+    .port = port,
+  };
+
+  ip46_address_copy (&args.addr, addr);
+  vlib_rpc_call_main_thread (wg_peer_update_endpoint_thread_fn, (u8 *) &args,
+			     sizeof (args));
+}
+
 int
 wg_peer_add (u32 tun_sw_if_index, const u8 public_key[NOISE_PUBLIC_KEY_LEN],
 	     u32 table_id, const ip46_address_t *endpoint,
@@ -345,7 +424,7 @@ wg_peer_add (u32 tun_sw_if_index, const u8 public_key[NOISE_PUBLIC_KEY_LEN],
   if (pool_elts (wg_peer_pool) > MAX_PEERS)
     return (VNET_API_ERROR_LIMIT_EXCEEDED);
 
-  pool_get (wg_peer_pool, peer);
+  pool_get_zero (wg_peer_pool, peer);
 
   wg_peer_init (vm, peer);
 
@@ -428,9 +507,9 @@ format_wg_peer (u8 * s, va_list * va)
 {
   index_t peeri = va_arg (*va, index_t);
   fib_prefix_t *allowed_ip;
-  adj_index_t *adj_index;
   u8 key[NOISE_KEY_LEN_BASE64];
   wg_peer_t *peer;
+  wg_peer_adj_t *peer_adj;
 
   peer = wg_peer_get (peeri);
   key_to_base64 (peer->remote.r_public, NOISE_PUBLIC_KEY_LEN, key);
@@ -443,9 +522,9 @@ format_wg_peer (u8 * s, va_list * va)
     peer->wg_sw_if_index, peer->persistent_keepalive_interval, peer->flags,
     pool_elts (peer->api_clients));
   s = format (s, "\n  adj:");
-  vec_foreach (adj_index, peer->adj_indices)
+  vec_foreach (peer_adj, peer->adjs)
     {
-      s = format (s, " %d", *adj_index);
+      s = format (s, " %d", peer_adj->adj_index);
     }
   s = format (s, "\n  key:%=s %U", key, format_hex_bytes,
 	      peer->remote.r_public, NOISE_PUBLIC_KEY_LEN);
diff --git a/src/plugins/wireguard/wireguard_peer.h b/src/plugins/wireguard/wireguard_peer.h
index a14f2692b1c..c07ea894b36 100644
--- a/src/plugins/wireguard/wireguard_peer.h
+++ b/src/plugins/wireguard/wireguard_peer.h
@@ -68,6 +68,13 @@ typedef enum
   WG_PEER_ESTABLISHED = 0x2,
 } wg_peer_flags;
 
+typedef struct wg_peer_adj_t_
+{
+  adj_index_t adj_index;
+  fib_node_index_t fib_entry_index;
+  u32 sibling_index;
+} wg_peer_adj_t;
+
 typedef struct wg_peer
 {
   noise_remote_t remote;
@@ -80,7 +87,7 @@ typedef struct wg_peer
   wg_peer_endpoint_t dst;
   wg_peer_endpoint_t src;
   u32 table_id;
-  adj_index_t *adj_indices;
+  wg_peer_adj_t *adjs;
 
   /* rewrite built from address information */
   u8 *rewrite;
@@ -144,6 +151,10 @@ adj_walk_rc_t wg_peer_adj_walk (adj_index_t ai, void *data);
 
 void wg_api_peer_event (index_t peeri, wg_peer_flags flags);
 void wg_peer_update_flags (index_t peeri, wg_peer_flags flag, bool add_del);
+void wg_peer_update_endpoint (index_t peeri, const ip46_address_t *addr,
+			      u16 port);
+void wg_peer_update_endpoint_from_mt (index_t peeri,
+				      const ip46_address_t *addr, u16 port);
 
 static inline bool
 wg_peer_is_dead (wg_peer_t *peer)
@@ -200,6 +211,12 @@ fib_prefix_is_cover_addr_46 (const fib_prefix_t *p1, const ip46_address_t *ip)
   return (false);
 }
 
+static inline bool
+wg_peer_can_send (wg_peer_t *peer)
+{
+  return peer && peer->rewrite;
+}
+
 #endif // __included_wg_peer_h__
 
 /*
diff --git a/src/plugins/wireguard/wireguard_send.c b/src/plugins/wireguard/wireguard_send.c
index 509fe70c777..93e808ad050 100644
--- a/src/plugins/wireguard/wireguard_send.c
+++ b/src/plugins/wireguard/wireguard_send.c
@@ -104,6 +104,9 @@ u8 *
 wg_build_rewrite (ip46_address_t *src_addr, u16 src_port,
 		  ip46_address_t *dst_addr, u16 dst_port, u8 is_ip4)
 {
+  if (ip46_address_is_zero (dst_addr) || 0 == dst_port)
+    return NULL;
+
   u8 *rewrite = NULL;
   if (is_ip4)
     {
@@ -151,6 +154,9 @@ wg_send_handshake (vlib_main_t * vm, wg_peer_t * peer, bool is_retry)
 {
   ASSERT (vm->thread_index == 0);
 
+  if (!wg_peer_can_send (peer))
+    return false;
+
   message_handshake_initiation_t packet;
 
   if (!is_retry)
@@ -224,6 +230,9 @@ wg_send_keepalive (vlib_main_t * vm, wg_peer_t * peer)
 {
   ASSERT (vm->thread_index == 0);
 
+  if (!wg_peer_can_send (peer))
+    return false;
+
   u32 size_of_packet = message_data_len (0);
   message_data_t *packet =
     (message_data_t *) wg_main.per_thread_data[vm->thread_index].data;
@@ -278,6 +287,9 @@ wg_send_handshake_response (vlib_main_t * vm, wg_peer_t * peer)
 {
   message_handshake_response_t packet;
 
+  if (!wg_peer_can_send (peer))
+    return false;
+
   if (noise_create_response (vm,
 			     &peer->remote,
 			     &packet.sender_index,
@@ -329,10 +341,14 @@ wg_send_handshake_cookie (vlib_main_t *vm, u32 sender_index,
 
   u32 bi0 = 0;
   u8 is_ip4 = ip46_address_is_ip4 (remote_addr);
+  bool ret;
   rewrite = wg_build_rewrite (wg_if_addr, wg_if_port, remote_addr, remote_port,
 			      is_ip4);
-  if (!wg_create_buffer (vm, rewrite, (u8 *) &packet, sizeof (packet), &bi0,
-			 is_ip4))
+
+  ret = wg_create_buffer (vm, rewrite, (u8 *) &packet, sizeof (packet), &bi0,
+			  is_ip4);
+  vec_free (rewrite);
+  if (!ret)
     return false;
 
   ip46_enqueue_packet (vm, bi0, is_ip4);