Implement a loopback instance allocation scheme.

To support creating loopback interfaces with a specific
instance number, a new CREATE_LOOPBACK_INSTANCE API call
with flag is_specified and value user_instance is introduced.
Presumably the existing CREATE_LOOPBACK API message will be
obsoleted and revmoved.

The VAT cli commands can now mention and format
the new field as 'instance %d' data.  If no instance
number is named, the old call CREATE_LOOPBACK is used
to maintain backward compatibility.  However, if the
instance is named, the new CREATE_LOOPBACK_INSTANCE
message will be used.

Both the dynamically allocated and user-requested instance
number are tracked in a bitvector.  If is_specified is 0,
the next free instance will be used..  A request for a specific
instance number will be granted if it is available.  On error,
the value ~0 is returned.

Change-Id: I849815563a5da736dcd6bccd262ef49b963f6643
Signed-off-by: Jon Loeliger <jdl@netgate.com>

4 files changed, 71 insertions, 1 deletions

diff --git a/src/vpp/api/api.c b/src/vpp/api/api.c
index e028fad4a39..f06894e8783 100644
--- a/src/vpp/api/api.c
+++ b/src/vpp/api/api.c
@@ -116,6 +116,7 @@ _(PROXY_ARP_INTFC_ENABLE_DISABLE, proxy_arp_intfc_enable_disable)       \
 _(VNET_GET_SUMMARY_STATS, vnet_get_summary_stats)			\
 _(RESET_FIB, reset_fib)							\
 _(CREATE_LOOPBACK, create_loopback)					\
+_(CREATE_LOOPBACK_INSTANCE, create_loopback_instance)			\
 _(CONTROL_PING, control_ping)                                           \
 _(CLI_REQUEST, cli_request)                                             \
 _(CLI_INBAND, cli_inband)						\
@@ -1026,7 +1027,7 @@ vl_api_create_loopback_t_handler (vl_api_create_loopback_t * mp)
   u32 sw_if_index;
   int rv;
 
-  rv = vnet_create_loopback_interface (&sw_if_index, mp->mac_address);
+  rv = vnet_create_loopback_interface (&sw_if_index, mp->mac_address, 0, 0);
 
   /* *INDENT-OFF* */
   REPLY_MACRO2(VL_API_CREATE_LOOPBACK_REPLY,
@@ -1036,6 +1037,26 @@ vl_api_create_loopback_t_handler (vl_api_create_loopback_t * mp)
   /* *INDENT-ON* */
 }
 
+static void vl_api_create_loopback_instance_t_handler
+  (vl_api_create_loopback_instance_t * mp)
+{
+  vl_api_create_loopback_instance_reply_t *rmp;
+  u32 sw_if_index;
+  u8 is_specified = mp->is_specified;
+  u32 user_instance = ntohl (mp->user_instance);
+  int rv;
+
+  rv = vnet_create_loopback_interface (&sw_if_index, mp->mac_address,
+				       is_specified, user_instance);
+
+  /* *INDENT-OFF* */
+  REPLY_MACRO2(VL_API_CREATE_LOOPBACK_INSTANCE_REPLY,
+  ({
+    rmp->sw_if_index = ntohl (sw_if_index);
+  }));
+  /* *INDENT-ON* */
+}
+
 static void
 vl_api_delete_loopback_t_handler (vl_api_delete_loopback_t * mp)
 {
diff --git a/src/vpp/api/custom_dump.c b/src/vpp/api/custom_dump.c
index c61e31bb8d5..ee0c4629b50 100644
--- a/src/vpp/api/custom_dump.c
+++ b/src/vpp/api/custom_dump.c
@@ -72,6 +72,18 @@ static void *vl_api_create_loopback_t_print
   FINISH;
 }
 
+static void *vl_api_create_loopback_instance_t_print
+  (vl_api_create_loopback_instance_t * mp, void *handle)
+{
+  u8 *s;
+
+  s = format (0, "SCRIPT: create_loopback ");
+  s = format (s, "mac %U ", format_ethernet_address, &mp->mac_address);
+  s = format (s, "instance %d ", ntohl (mp->user_instance));
+
+  FINISH;
+}
+
 static void *vl_api_delete_loopback_t_print
   (vl_api_delete_loopback_t * mp, void *handle)
 {
@@ -2821,6 +2833,7 @@ foreach_custom_print_no_arg_function
 #undef _
 #define foreach_custom_print_function                                   \
 _(CREATE_LOOPBACK, create_loopback)                                     \
+_(CREATE_LOOPBACK_INSTANCE, create_loopback_instance)                   \
 _(SW_INTERFACE_SET_FLAGS, sw_interface_set_flags)                       \
 _(SW_INTERFACE_ADD_DEL_ADDRESS, sw_interface_add_del_address)           \
 _(SW_INTERFACE_SET_TABLE, sw_interface_set_table)                       \
diff --git a/src/vpp/api/test_client.c b/src/vpp/api/test_client.c
index ceafc35788d..8b61f4f3a05 100644
--- a/src/vpp/api/test_client.c
+++ b/src/vpp/api/test_client.c
@@ -534,6 +534,13 @@ static void vl_api_create_loopback_reply_t_handler
 	   ntohl (mp->retval), ntohl (mp->sw_if_index));
 }
 
+static void vl_api_create_loopback_instance_reply_t_handler
+  (vl_api_create_loopback_instance_reply_t * mp)
+{
+  fformat (stdout, "create loopback status %d, sw_if_index %d\n",
+	   ntohl (mp->retval), ntohl (mp->sw_if_index));
+}
+
 static void
 vl_api_sr_tunnel_add_del_reply_t_handler (vl_api_sr_tunnel_add_del_reply_t *
 					  mp)
@@ -598,6 +605,7 @@ _(SW_INTERFACE_IP6ND_RA_PREFIX_REPLY, sw_interface_ip6nd_ra_prefix_reply) \
 _(SW_INTERFACE_IP6_ENABLE_DISABLE_REPLY, sw_interface_ip6_enable_disable_reply) \
 _(SW_INTERFACE_IP6_SET_LINK_LOCAL_ADDRESS_REPLY, sw_interface_ip6_set_link_local_address_reply) \
  _(CREATE_LOOPBACK_REPLY, create_loopback_reply)			\
+ _(CREATE_LOOPBACK_INSTANCE_REPLY, create_loopback_instance_reply)	\
 _(L2_PATCH_ADD_DEL_REPLY, l2_patch_add_del_reply)			\
 _(SR_TUNNEL_ADD_DEL_REPLY,sr_tunnel_add_del_reply)          \
 _(SW_INTERFACE_SET_L2_XCONNECT_REPLY, sw_interface_set_l2_xconnect_reply) \
diff --git a/src/vpp/api/vpe.api b/src/vpp/api/vpe.api
index 7f9c203807c..a4ba180dfb2 100644
--- a/src/vpp/api/vpe.api
+++ b/src/vpp/api/vpe.api
@@ -425,6 +425,34 @@ define create_loopback_reply
   u32 sw_if_index;
 };
 
+/** \brief Create loopback interface instance request
+    @param client_index - opaque cookie to identify the sender
+    @param context - sender context, to match reply w/ request
+    @param mac_address - mac addr to assign to the interface if none-zero
+    @param is_specified - if non-0, a specific user_instance is being requested
+    @param user_instance - requested instance, ~0 => dynamically allocate
+*/
+define create_loopback_instance
+{
+  u32 client_index;
+  u32 context;
+  u8 mac_address[6];
+  u8 is_specified;
+  u32 user_instance;
+};
+
+/** \brief Create loopback interface instance response
+    @param context - sender context, to match reply w/ request
+    @param sw_if_index - sw index of the interface that was created
+    @param retval - return code for the request
+*/
+define create_loopback_instance_reply
+{
+  u32 context;
+  i32 retval;
+  u32 sw_if_index;
+};
+
 /** \brief Delete loopback interface request
     @param client_index - opaque cookie to identify the sender
     @param context - sender context, to match reply w/ request