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, 77 insertions, 0 deletions

diff --git a/src/vat/api_format.c b/src/vat/api_format.c
index eebad05fa3c..b1aaa6992c5 100644
--- a/src/vat/api_format.c
+++ b/src/vat/api_format.c
@@ -22,6 +22,7 @@
 #include <vlibapi/api.h>
 #include <vlibmemory/api.h>
 #include <vnet/ip/ip.h>
+#include <vnet/ip/ip_neighbor.h>
 #include <vnet/l2/l2_input.h>
 #include <vnet/l2tp/l2tp.h>
 #include <vnet/vxlan/vxlan.h>
@@ -5450,6 +5451,7 @@ _(l2_interface_vlan_tag_rewrite_reply)                  \
 _(modify_vhost_user_if_reply)                           \
 _(delete_vhost_user_if_reply)                           \
 _(ip_probe_neighbor_reply)                              \
+_(ip_scan_neighbor_enable_disable_reply)                \
 _(want_ip4_arp_events_reply)                            \
 _(want_ip6_nd_events_reply)                             \
 _(want_l2_macs_events_reply)                            \
@@ -5697,6 +5699,7 @@ _(VXLAN_GPE_ADD_DEL_TUNNEL_REPLY, vxlan_gpe_add_del_tunnel_reply)	\
 _(VXLAN_GPE_TUNNEL_DETAILS, vxlan_gpe_tunnel_details)                   \
 _(INTERFACE_NAME_RENUMBER_REPLY, interface_name_renumber_reply)		\
 _(IP_PROBE_NEIGHBOR_REPLY, ip_probe_neighbor_reply)			\
+_(IP_SCAN_NEIGHBOR_ENABLE_DISABLE_REPLY, ip_scan_neighbor_enable_disable_reply) \
 _(WANT_IP4_ARP_EVENTS_REPLY, want_ip4_arp_events_reply)			\
 _(IP4_ARP_EVENT, ip4_arp_event)                                         \
 _(WANT_IP6_ND_EVENTS_REPLY, want_ip6_nd_events_reply)			\
@@ -14416,6 +14419,78 @@ api_ip_probe_neighbor (vat_main_t * vam)
 }
 
 static int
+api_ip_scan_neighbor_enable_disable (vat_main_t * vam)
+{
+  unformat_input_t *i = vam->input;
+  vl_api_ip_scan_neighbor_enable_disable_t *mp;
+  u8 mode = IP_SCAN_V46_NEIGHBORS;
+  u32 interval = 0, time = 0, update = 0, delay = 0, stale = 0;
+  int ret;
+
+  while (unformat_check_input (i) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (i, "ip4"))
+	mode = IP_SCAN_V4_NEIGHBORS;
+      else if (unformat (i, "ip6"))
+	mode = IP_SCAN_V6_NEIGHBORS;
+      if (unformat (i, "both"))
+	mode = IP_SCAN_V46_NEIGHBORS;
+      else if (unformat (i, "disable"))
+	mode = IP_SCAN_DISABLED;
+      else if (unformat (i, "interval %d", &interval))
+	;
+      else if (unformat (i, "max-time %d", &time))
+	;
+      else if (unformat (i, "max-update %d", &update))
+	;
+      else if (unformat (i, "delay %d", &delay))
+	;
+      else if (unformat (i, "stale %d", &stale))
+	;
+      else
+	break;
+    }
+
+  if (interval > 255)
+    {
+      errmsg ("interval cannot exceed 255 minutes.");
+      return -99;
+    }
+  if (time > 255)
+    {
+      errmsg ("max-time cannot exceed 255 usec.");
+      return -99;
+    }
+  if (update > 255)
+    {
+      errmsg ("max-update cannot exceed 255.");
+      return -99;
+    }
+  if (delay > 255)
+    {
+      errmsg ("delay cannot exceed 255 msec.");
+      return -99;
+    }
+  if (stale > 255)
+    {
+      errmsg ("stale cannot exceed 255 minutes.");
+      return -99;
+    }
+
+  M (IP_SCAN_NEIGHBOR_ENABLE_DISABLE, mp);
+  mp->mode = mode;
+  mp->scan_interval = interval;
+  mp->max_proc_time = time;
+  mp->max_update = update;
+  mp->scan_int_delay = delay;
+  mp->stale_threshold = stale;
+
+  S (mp);
+  W (ret);
+  return ret;
+}
+
+static int
 api_want_ip4_arp_events (vat_main_t * vam)
 {
   unformat_input_t *line_input = vam->input;
@@ -23406,6 +23481,8 @@ _(input_acl_set_interface,                                              \
   "<intfc> | sw_if_index <nn> [ip4-table <nn>] [ip6-table <nn>]\n"      \
   "  [l2-table <nn>] [del]")                                            \
 _(ip_probe_neighbor, "(<intc> | sw_if_index <nn>) address <ip4|ip6-addr>") \
+_(ip_scan_neighbor_enable_disable, "[ip4|ip6|both|disable] [interval <n-min>]\n" \
+  "  [max-time <n-usec>] [max-update <n>] [delay <n-msec>] [stale <n-min>]") \
 _(want_ip4_arp_events, "address <ip4-address> [del]")                   \
 _(want_ip6_nd_events, "address <ip6-address> [del]")                    \
 _(want_l2_macs_events, "[disable] [learn-limit <n>] [scan-delay <n>] [max-entries <n>]") \