From 8af78b8e360f12ffb9e347868a6e820bee618b81 Mon Sep 17 00:00:00 2001
From: Ole Troan <otroan@employees.org>
Date: Thu, 31 Aug 2023 09:48:45 +0200
Subject: [PATCH] arping: api to return responder mac address

The new arping_acd call includes the responders mac address in the reply.
Enabling a client doing address conflict detection to identify if it
is itself that is replying or that it is another host uses the IP
address.

Type: feature
Change-Id: Ia4bab2af1086f06ed71ba42e2e07368d4e330a27
Signed-off-by: Ole Troan <otroan@employees.org>
---
 src/plugins/arping/arping.api    | 23 +++++++++++++++++++++++
 src/plugins/arping/arping_api.c  | 32 ++++++++++++++++++++++++++++++++
 src/plugins/arping/arping_test.c | 13 +++++++++++++
 3 files changed, 68 insertions(+)

diff --git a/src/plugins/arping/arping.api b/src/plugins/arping/arping.api
index f797b8cf3aa..9ec01a9b55d 100644
--- a/src/plugins/arping/arping.api
+++ b/src/plugins/arping/arping.api
@@ -18,6 +18,7 @@
 option version = "1.0.0";
 import "vnet/interface_types.api";
 import "vnet/ip/ip_types.api";
+import "vnet/ethernet/ethernet_types.api";
 
 /** \brief
     @param client_index - opaque cookie to identify the sender
@@ -54,6 +55,28 @@ define arping_reply
   u32 reply_count;
 };
 
+/*
+ * Address Conflict Detection
+ */
+define arping_acd
+{
+  u32 client_index;
+  u32 context;
+  vl_api_address_t address;
+  vl_api_interface_index_t sw_if_index;
+  bool is_garp;
+  u32 repeat [default=1];
+  f64 interval [default=1.0];
+};
+
+define arping_acd_reply
+{
+  u32 context;
+  i32 retval;
+  u32 reply_count;
+  vl_api_mac_address_t mac_address;
+};
+
 /*
  * Local Variables:
  * eval: (c-set-style "gnu")
diff --git a/src/plugins/arping/arping_api.c b/src/plugins/arping/arping_api.c
index 50fbb04115b..1b3431f2f39 100644
--- a/src/plugins/arping/arping_api.c
+++ b/src/plugins/arping/arping_api.c
@@ -26,6 +26,7 @@
 
 #include <vlibapi/api.h>
 #include <vlibmemory/api.h>
+#include <vnet/ethernet/ethernet_types_api.h>
 
 /* define message IDs */
 #include <arping/arping.api_enum.h>
@@ -62,6 +63,36 @@ vl_api_arping_t_handler (vl_api_arping_t *mp)
 		({ rmp->reply_count = ntohl (args.reply_count); }));
 }
 
+static void
+vl_api_arping_acd_t_handler (vl_api_arping_acd_t *mp)
+{
+  vlib_main_t *vm = vlib_get_main ();
+  arping_main_t *am = &arping_main;
+  vl_api_arping_acd_reply_t *rmp;
+  arping_args_t args = { 0 };
+  int rv;
+
+  if (mp->sw_if_index != ~0)
+    VALIDATE_SW_IF_INDEX (mp);
+
+  ip_address_decode2 (&mp->address, &args.address);
+  args.interval = clib_net_to_host_f64 (mp->interval);
+  args.repeat = ntohl (mp->repeat);
+  args.is_garp = mp->is_garp;
+  args.sw_if_index = ntohl (mp->sw_if_index);
+  args.silence = 1;
+
+  arping_run_command (vm, &args);
+  rv = args.rv;
+
+  BAD_SW_IF_INDEX_LABEL;
+
+  REPLY_MACRO2 (VL_API_ARPING_ACD_REPLY, ({
+		  rmp->reply_count = ntohl (args.reply_count);
+		  mac_address_encode (&args.recv.from4.mac, rmp->mac_address);
+		}));
+}
+
 /* set tup the API message handling tables */
 #include <arping/arping.api.c>
 clib_error_t *
@@ -75,6 +106,7 @@ arping_plugin_api_hookup (vlib_main_t *vm)
 
   /* Mark API as mp safe */
   vl_api_set_msg_thread_safe (vam, am->msg_id_base + VL_API_ARPING, 1);
+  vl_api_set_msg_thread_safe (vam, am->msg_id_base + VL_API_ARPING_ACD, 1);
 
   return 0;
 }
diff --git a/src/plugins/arping/arping_test.c b/src/plugins/arping/arping_test.c
index 00b0b98ab9a..7cd85912bd2 100644
--- a/src/plugins/arping/arping_test.c
+++ b/src/plugins/arping/arping_test.c
@@ -154,6 +154,19 @@ vl_api_arping_reply_t_handler (vl_api_arping_reply_t *mp)
   vam->result_ready = 1;
 }
 
+static int
+api_arping_acd (vat_main_t *vam)
+{
+  // NOT YET IMPLEMENTED
+  return -99;
+}
+
+static void
+vl_api_arping_acd_reply_t_handler (vl_api_arping_reply_t *mp)
+{
+  // NOT YET IMPLEMENTED
+}
+
 #include <arping/arping.api_test.c>
 
 /*
-- 
2.16.6