Check get packet template allocation failure (VPP-1321)

After calling vlib_packet_template_get_packet(), make sure
packet buffer is allocated before using it.

Change-Id: Idb5199f4e2c9596137b2101e502d611f474a6ffe
Signed-off-by: John Lo <loj@cisco.com>
diff --git a/src/plugins/cdp/cdp_periodic.c b/src/plugins/cdp/cdp_periodic.c
index c67af00..a4c4bb9 100644
--- a/src/plugins/cdp/cdp_periodic.c
+++ b/src/plugins/cdp/cdp_periodic.c
@@ -195,6 +195,9 @@
       h0 = vlib_packet_template_get_packet
 	(vm, &cm->packet_templates[n->packet_template_index], &bi0);
 
+      if (!h0)
+	break;
+
       hw = vnet_get_sup_hw_interface (vnm, n->sw_if_index);
 
       t0 = (u8 *) & h0->cdp.data;
@@ -251,6 +254,9 @@
       h0 = vlib_packet_template_get_packet
 	(vm, &cm->packet_templates[n->packet_template_index], &bi0);
 
+      if (!h0)
+	break;
+
       hw = vnet_get_sup_hw_interface (vnm, n->sw_if_index);
 
       t0 = (u8 *) & h0->cdp.data;
diff --git a/src/vnet/ethernet/arp.c b/src/vnet/ethernet/arp.c
index 37e3e88..a17f7da 100644
--- a/src/vnet/ethernet/arp.c
+++ b/src/vnet/ethernet/arp.c
@@ -352,6 +352,8 @@
   h =
     vlib_packet_template_get_packet (vm, &im->ip4_arp_request_packet_template,
 				     &bi);
+  if (!h)
+    return;
 
   hi = vnet_get_sup_hw_interface (vnm, adj->rewrite_header.sw_if_index);
 
@@ -2579,6 +2581,10 @@
       u32 bi = 0;
       ethernet_arp_header_t *h = vlib_packet_template_get_packet
 	(vm, &i4m->ip4_arp_request_packet_template, &bi);
+
+      if (!h)
+	return;
+
       clib_memcpy (h->ip4_over_ethernet[0].ethernet, hi->hw_address,
 		   sizeof (h->ip4_over_ethernet[0].ethernet));
       clib_memcpy (h->ip4_over_ethernet[1].ethernet, hi->hw_address,
diff --git a/src/vnet/ip/ip4_forward.c b/src/vnet/ip/ip4_forward.c
index 0035cc8..677f88c 100644
--- a/src/vnet/ip/ip4_forward.c
+++ b/src/vnet/ip/ip4_forward.c
@@ -1960,6 +1960,9 @@
 				       &im->ip4_arp_request_packet_template,
 				       &bi);
 
+  if (!h)
+    return clib_error_return (0, "ARP request packet allocation failed");
+
   hi = vnet_get_sup_hw_interface (vnm, sw_if_index);
   if (PREDICT_FALSE (!hi->hw_address))
     {
diff --git a/src/vnet/ip/ip6_forward.c b/src/vnet/ip/ip6_forward.c
index 5ea7d8d..cf1011f 100644
--- a/src/vnet/ip/ip6_forward.c
+++ b/src/vnet/ip/ip6_forward.c
@@ -1476,6 +1476,8 @@
     vlib_packet_template_get_packet (vm,
 				     &im->discover_neighbor_packet_template,
 				     &bi);
+  if (!h)
+    return clib_error_return (0, "ICMP6 NS packet allocation failed");
 
   hi = vnet_get_sup_hw_interface (vnm, sw_if_index);
 
diff --git a/src/vnet/ip/ip6_neighbor.c b/src/vnet/ip/ip6_neighbor.c
index e281d7e..6d91224 100644
--- a/src/vnet/ip/ip6_neighbor.c
+++ b/src/vnet/ip/ip6_neighbor.c
@@ -466,6 +466,8 @@
   h = vlib_packet_template_get_packet (vm,
 				       &im->discover_neighbor_packet_template,
 				       &bi);
+  if (!h)
+    return;
 
   hi = vnet_get_sup_hw_interface (vnm, adj->rewrite_header.sw_if_index);
 
@@ -3285,6 +3287,8 @@
 
 	    h0 = vlib_packet_template_get_packet
 	      (vm, &im->discover_neighbor_packet_template, &bi0);
+	    if (!h0)
+	      continue;
 
 	    /*
 	     * Build ethernet header.
@@ -5037,6 +5041,9 @@
 	vlib_packet_template_get_packet (vm,
 					 &i6m->discover_neighbor_packet_template,
 					 &bi);
+      if (!h)
+	return;
+
       ip6_set_reserved_multicast_address (&h->ip.dst_address,
 					  IP6_MULTICAST_SCOPE_link_local,
 					  IP6_MULTICAST_GROUP_ID_all_hosts);