Repair vlib API socket server

- Teach vpp_api_test to send/receive API messages over sockets
- Add memfd-based shared memory
- Add api messages to create memfd-based shared memory segments
- vpp_api_test supports both socket and shared memory segment connections
- vpp_api_test pivot from socket to shared memory API messaging
- add socket client support to libvlibclient.so
- dead client reaper sends ping messages, container-friendly
- dead client reaper falls back to kill (<pid>, 0) live checking
  if e.g. a python app goes silent for tens of seconds
- handle ping messages in python client support code
- teach show api ring about pairwise shared-memory segments
- fix ip probing of already resolved destinations (VPP-998)

We'll need this work to implement proper host-stack client isolation

Change-Id: Ic23b65f75c854d0393d9a2e9d6b122a9551be769
Signed-off-by: Dave Barach <dave@barachs.net>
Signed-off-by: Dave Wallace <dwallacelf@gmail.com>
Signed-off-by: Florin Coras <fcoras@cisco.com>

1 files changed, 16 insertions, 8 deletions

diff --git a/src/vnet/ip/ip4_forward.c b/src/vnet/ip/ip4_forward.c
index 0a34497da7a..58cfd1816d8 100755
--- a/src/vnet/ip/ip4_forward.c
+++ b/src/vnet/ip/ip4_forward.c
@@ -2257,14 +2257,6 @@ ip4_probe_neighbor (vlib_main_t * vm, ip4_address_t * dst, u32 sw_if_index)
 	 sw_if_index);
     }
 
-  ip46_address_t nh = {
-    .ip4 = *dst,
-  };
-
-  ai = adj_nbr_add_or_lock (FIB_PROTOCOL_IP4,
-			    VNET_LINK_IP4, &nh, sw_if_index);
-  adj = adj_get (ai);
-
   h = vlib_packet_template_get_packet (vm,
 				       &im->ip4_arp_request_packet_template,
 				       &bi);
@@ -2288,6 +2280,22 @@ ip4_probe_neighbor (vlib_main_t * vm, ip4_address_t * dst, u32 sw_if_index)
   vnet_buffer (b)->sw_if_index[VLIB_RX] =
     vnet_buffer (b)->sw_if_index[VLIB_TX] = sw_if_index;
 
+  ip46_address_t nh = {
+    .ip4 = *dst,
+  };
+
+  ai = adj_nbr_add_or_lock (FIB_PROTOCOL_IP4,
+			    VNET_LINK_IP4, &nh, sw_if_index);
+  adj = adj_get (ai);
+
+  /* Peer has been previously resolved, retrieve glean adj instead */
+  if (adj->lookup_next_index == IP_LOOKUP_NEXT_REWRITE)
+    {
+      adj_unlock (ai);
+      ai = adj_glean_add_or_lock (FIB_PROTOCOL_IP4, sw_if_index, &nh);
+      adj = adj_get (ai);
+    }
+
   /* Add encapsulation string for software interface (e.g. ethernet header). */
   vnet_rewrite_one_header (adj[0], h, sizeof (ethernet_header_t));
   vlib_buffer_advance (b, -adj->rewrite_header.data_bytes);