Periodic scan and probe of IP neighbors to maintain neighbor pools

Scan IPv4 and IPv6 neigbor pool entries once a minute to keep them
up to date. The neighbor of an entry is probed if its time-stamp
is older than 1 minute. If the neighbor respond, its time-stamp
will be updated. If there is no response from a neighbor, its
entry will be deleted when the time-stamp of the entry become more
than 4 minutes old. Static neighbor entries are not probed nor
deleted.

Implemented CLI and API to enable and disable priodic scan of IPv4,
IPv6 or both types of IP neighbors. CLI is "ip scan-neighbor" and
API is "ip_scan_neighbor_enable_disable". Other IP neighbor scan
parameters can also be changed from their defaults via the CLI/API.

Change-Id: Id1a0a934ace15d03db845aa698bcbb9cdabebfcd
Signed-off-by: John Lo <loj@cisco.com>

1 files changed, 25 insertions, 1 deletions

diff --git a/src/vnet/ip/ip.api b/src/vnet/ip/ip.api
index bf16c180d4d..d59297b1c20 100644
--- a/src/vnet/ip/ip.api
+++ b/src/vnet/ip/ip.api
@@ -19,7 +19,7 @@
     called through a shared memory interface. 
 */
 
-option version = "1.2.2";
+option version = "1.2.3";
 import "vnet/fib/fib_types.api";
 
 /** \brief Add / del table request
@@ -651,6 +651,30 @@ autoreply define ip_source_and_port_range_check_interface_add_del
   u32 udp_out_vrf_id;
 };
 
+/** \brief Enable/disable periodic IP neighbor scan
+    @param client_index - opaque cookie to identify the sender
+    @param context - sender context, to match reply w/ request
+    @param mode - 0: disable, 1: IPv4, 2: IPv6, 3: both IPv4/v6
+    @param scan_interval - neighbor scan interval in minutes, 0: default to 1
+    @param max_proc_time - max processing time per run in usec, 0: default to 20
+    @param max_update - max neighbor probe/delete per run, 0: default to 10
+    @param scan_int_delay - delay in msec to resume scan if exceed max proc
+                            time or update, 0: default to 1
+    @param stale_threshold - threshold in minutes for neighbor deletion, 
+                             0: default to 4*scan_interval
+*/
+autoreply define ip_scan_neighbor_enable_disable
+{
+  u32 client_index;
+  u32 context;
+  u8 mode;
+  u8 scan_interval;
+  u8 max_proc_time;
+  u8 max_update;
+  u8 scan_int_delay;
+  u8 stale_threshold;
+};
+
 /** \brief IP probe neighbor address on an interface by sending an
            ARP request (for IP4) or ICMP6 Neighbor Solicitation (for IP6)
     @param client_index - opaque cookie to identify the sender