src/vnet/feature/feature.c - fdio/vpp - Gitiles

 /*
  * Copyright (c) 2016 Cisco and/or its affiliates.
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at:
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include <vnet/feature/feature.h>
 #include <vnet/adj/adj.h>

 vnet_feature_main_t feature_main;

 static clib_error_t *
 vnet_feature_init (vlib_main_t * vm)
 {
   vnet_feature_main_t *fm = &feature_main;
   vnet_feature_registration_t *freg;
   vnet_feature_arc_registration_t *areg;
   u32 arc_index = 0;

   fm->arc_index_by_name = hash_create_string (0, sizeof (uword));
   areg = fm->next_arc;

   /* process feature arc registrations */
   while (areg)
     {
       char *s;
       int i = 0;
       areg->feature_arc_index = arc_index;
       if (areg->arc_index_ptr)
 	*areg->arc_index_ptr = arc_index;
       hash_set_mem (fm->arc_index_by_name, areg->arc_name,
 		    pointer_to_uword (areg));

       /* process start nodes */
       while ((s = areg->start_nodes[i]))
 	{
 	  i++;
 	}
       areg->n_start_nodes = i;

       /* next */
       areg = areg->next;
       arc_index++;
     }

   vec_validate (fm->next_feature_by_arc, arc_index - 1);
   vec_validate (fm->feature_nodes, arc_index - 1);
   vec_validate (fm->feature_config_mains, arc_index - 1);
   vec_validate (fm->next_feature_by_name, arc_index - 1);
   vec_validate (fm->sw_if_index_has_features, arc_index - 1);
   vec_validate (fm->feature_count_by_sw_if_index, arc_index - 1);

   freg = fm->next_feature;
   while (freg)
     {
       vnet_feature_registration_t *next;
       uword *p = hash_get_mem (fm->arc_index_by_name, freg->arc_name);
       if (p == 0)
 	{
 	  /* Don't start vpp with broken features arcs */
 	  clib_warning ("Unknown feature arc '%s'", freg->arc_name);
 	  os_exit (1);
 	}

       areg = uword_to_pointer (p[0], vnet_feature_arc_registration_t *);
       arc_index = areg->feature_arc_index;

       next = freg->next;
       freg->next = fm->next_feature_by_arc[arc_index];
       fm->next_feature_by_arc[arc_index] = freg;

       /* next */
       freg = next;
     }

   areg = fm->next_arc;
   while (areg)
     {
       clib_error_t *error;
       vnet_feature_config_main_t *cm;
       vnet_config_main_t *vcm;

       arc_index = areg->feature_arc_index;
       cm = &fm->feature_config_mains[arc_index];
       vcm = &cm->config_main;
       if ((error = vnet_feature_arc_init (vm, vcm,
 					  areg->start_nodes,
 					  areg->n_start_nodes,
 					  fm->next_feature_by_arc[arc_index],
 					  &fm->feature_nodes[arc_index])))
 	{
 	  clib_error_report (error);
 	  os_exit (1);
 	}

       fm->next_feature_by_name[arc_index] =
 	hash_create_string (0, sizeof (uword));
       freg = fm->next_feature_by_arc[arc_index];

       while (freg)
 	{
 	  hash_set_mem (fm->next_feature_by_name[arc_index],
 			freg->node_name, pointer_to_uword (freg));
 	  freg = freg->next;
 	}

       /* next */
       areg = areg->next;
       arc_index++;
     }

   return 0;
 }

 VLIB_INIT_FUNCTION (vnet_feature_init);

 u8
 vnet_get_feature_arc_index (const char *s)
 {
   vnet_feature_main_t *fm = &feature_main;
   vnet_feature_arc_registration_t *reg;
   uword *p;

   p = hash_get_mem (fm->arc_index_by_name, s);
   if (p == 0)
     return ~0;

   reg = uword_to_pointer (p[0], vnet_feature_arc_registration_t *);
   return reg->feature_arc_index;
 }

 vnet_feature_registration_t *
 vnet_get_feature_reg (const char *arc_name, const char *node_name)
 {
   u8 arc_index;

   arc_index = vnet_get_feature_arc_index (arc_name);
   if (arc_index == (u8) ~ 0)
     return 0;

   vnet_feature_main_t *fm = &feature_main;
   vnet_feature_registration_t *reg;
   uword *p;

   p = hash_get_mem (fm->next_feature_by_name[arc_index], node_name);
   if (p == 0)
     return 0;

   reg = uword_to_pointer (p[0], vnet_feature_registration_t *);
   return reg;
 }

 u32
 vnet_get_feature_index (u8 arc, const char *s)
 {
   vnet_feature_main_t *fm = &feature_main;
   vnet_feature_registration_t *reg;
   uword *p;

   if (s == 0)
     return ~0;

   p = hash_get_mem (fm->next_feature_by_name[arc], s);
   if (p == 0)
     return ~0;

   reg = uword_to_pointer (p[0], vnet_feature_registration_t *);
   return reg->feature_index;
 }

 int
 vnet_feature_enable_disable_with_index (u8 arc_index, u32 feature_index,
 					u32 sw_if_index, int enable_disable,
 					void *feature_config,
 					u32 n_feature_config_bytes)
 {
   vnet_feature_main_t *fm = &feature_main;
   vnet_feature_config_main_t *cm;
   i16 feature_count;
   u32 ci;

   if (arc_index == (u8) ~ 0)
     return VNET_API_ERROR_INVALID_VALUE;

   if (feature_index == ~0)
     return VNET_API_ERROR_INVALID_VALUE_2;

   cm = &fm->feature_config_mains[arc_index];
   vec_validate_init_empty (cm->config_index_by_sw_if_index, sw_if_index, ~0);
   ci = cm->config_index_by_sw_if_index[sw_if_index];

   vec_validate (fm->feature_count_by_sw_if_index[arc_index], sw_if_index);
   feature_count = fm->feature_count_by_sw_if_index[arc_index][sw_if_index];

   if (!enable_disable && feature_count < 1)
     return 0;

   ci = (enable_disable
 	? vnet_config_add_feature
 	: vnet_config_del_feature)
     (vlib_get_main (), &cm->config_main, ci, feature_index, feature_config,
      n_feature_config_bytes);
   cm->config_index_by_sw_if_index[sw_if_index] = ci;

   /* update feature count */
   enable_disable = (enable_disable > 0);
   feature_count += enable_disable ? 1 : -1;
   ASSERT (feature_count >= 0);

   fm->sw_if_index_has_features[arc_index] =
     clib_bitmap_set (fm->sw_if_index_has_features[arc_index], sw_if_index,
 		     (feature_count > 0));
   adj_feature_update (sw_if_index, arc_index, (feature_count > 0));

   fm->feature_count_by_sw_if_index[arc_index][sw_if_index] = feature_count;
   return 0;
 }

 int
 vnet_feature_enable_disable (const char *arc_name, const char *node_name,
 			     u32 sw_if_index, int enable_disable,
 			     void *feature_config, u32 n_feature_config_bytes)
 {
   u32 feature_index;
   u8 arc_index;

   arc_index = vnet_get_feature_arc_index (arc_name);

   if (arc_index == (u8) ~ 0)
     return VNET_API_ERROR_INVALID_VALUE;

   feature_index = vnet_get_feature_index (arc_index, node_name);

   return vnet_feature_enable_disable_with_index (arc_index, feature_index,
 						 sw_if_index, enable_disable,
 						 feature_config,
 						 n_feature_config_bytes);
 }


 /** Display the set of available driver features.
     Useful for verifying that expected features are present
 */

 static clib_error_t *
 show_features_command_fn (vlib_main_t * vm,
 			  unformat_input_t * input, vlib_cli_command_t * cmd)
 {
   vnet_feature_main_t *fm = &feature_main;
   vnet_feature_arc_registration_t *areg;
   vnet_feature_registration_t *freg;

   vlib_cli_output (vm, "Available feature paths");

   areg = fm->next_arc;
   while (areg)
     {
       vlib_cli_output (vm, "%s:", areg->arc_name);
       freg = fm->next_feature_by_arc[areg->feature_arc_index];
       while (freg)
 	{
 	  vlib_cli_output (vm, "  %s\n", freg->node_name);
 	  freg = freg->next;
 	}


       /* next */
       areg = areg->next;
     }

   return 0;
 }

 /*?
  * Display the set of available driver features
  *
  * @cliexpar
  * Example:
  * @cliexcmd{show ip features}
  * @cliexend
  * @endparblock
 ?*/
 /* *INDENT-OFF* */
 VLIB_CLI_COMMAND (show_features_command, static) = {
   .path = "show features",
   .short_help = "show features",
   .function = show_features_command_fn,
 };
 /* *INDENT-ON* */

 /** Display the set of driver features configured on a specific interface
   * Called by "show interface" handler
  */

 void
 vnet_interface_features_show (vlib_main_t * vm, u32 sw_if_index)
 {
   vnet_feature_main_t *fm = &feature_main;
   u32 node_index, current_config_index;
   u16 feature_arc;
   vnet_feature_config_main_t *cm = fm->feature_config_mains;
   vnet_feature_arc_registration_t *areg;
   vnet_config_main_t *vcm;
   vnet_config_t *cfg;
   u32 cfg_index;
   vnet_config_feature_t *feat;
   vlib_node_t *n;
   int i;

   vlib_cli_output (vm, "Driver feature paths configured on %U...",
 		   format_vnet_sw_if_index_name,
 		   vnet_get_main (), sw_if_index);

   areg = fm->next_arc;
   while (areg)
     {
       feature_arc = areg->feature_arc_index;
       vcm = &(cm[feature_arc].config_main);

       vlib_cli_output (vm, "\n%s:", areg->arc_name);
       areg = areg->next;

       if (NULL == cm[feature_arc].config_index_by_sw_if_index ||
 	  vec_len (cm[feature_arc].config_index_by_sw_if_index) <=
 	  sw_if_index)
 	{
 	  vlib_cli_output (vm, "  none configured");
 	  continue;
 	}

       current_config_index =
 	vec_elt (cm[feature_arc].config_index_by_sw_if_index, sw_if_index);

       if (current_config_index == ~0)
 	{
 	  vlib_cli_output (vm, "  none configured");
 	  continue;
 	}

       ASSERT (current_config_index
 	      < vec_len (vcm->config_pool_index_by_user_index));

       cfg_index = vcm->config_pool_index_by_user_index[current_config_index];
       cfg = pool_elt_at_index (vcm->config_pool, cfg_index);

       for (i = 0; i < vec_len (cfg->features); i++)
 	{
 	  feat = cfg->features + i;
 	  node_index = feat->node_index;
 	  n = vlib_get_node (vm, node_index);
 	  vlib_cli_output (vm, "  %v", n->name);
 	}
     }
 }

 static clib_error_t *
 set_interface_features_command_fn (vlib_main_t * vm,
 				   unformat_input_t * input,
 				   vlib_cli_command_t * cmd)
 {
   vnet_main_t *vnm = vnet_get_main ();
   unformat_input_t _line_input, *line_input = &_line_input;
   clib_error_t *error = 0;

   u8 *arc_name = 0;
   u8 *feature_name = 0;
   u32 sw_if_index = ~0;
   u8 enable = 1;

   /* Get a line of input. */
   if (!unformat_user (input, unformat_line_input, line_input))
     goto done;

   while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT)
     {
       if (unformat
 	  (line_input, "%U %v", unformat_vnet_sw_interface, vnm, &sw_if_index,
 	   &feature_name))
 	;
       else if (unformat (line_input, "arc %v", &arc_name))
 	;
       else if (unformat (line_input, "disable"))
 	enable = 0;
       else
 	{
 	  error = unformat_parse_error (line_input);
 	  goto done;
 	}
     }

   if (sw_if_index == ~0)
     {
       error = clib_error_return (0, "Interface not specified...");
       goto done;
     }

   vec_add1 (arc_name, 0);
   vec_add1 (feature_name, 0);

   vnet_feature_registration_t *reg;
   reg =
     vnet_get_feature_reg ((const char *) arc_name,
 			  (const char *) feature_name);
   if (reg == 0)
     {
       error = clib_error_return (0, "Unknown feature...");
       goto done;
     }
   if (reg->enable_disable_cb)
     error = reg->enable_disable_cb (sw_if_index, enable);
   if (!error)
     vnet_feature_enable_disable ((const char *) arc_name,
 				 (const char *) feature_name, sw_if_index,
 				 enable, 0, 0);

 done:
   vec_free (feature_name);
   vec_free (arc_name);
   unformat_free (line_input);
   return error;
 }

 /*?
  * Set feature for given interface
  *
  * @cliexpar
  * Example:
  * @cliexcmd{set interface feature GigabitEthernet2/0/0 ip4_flow_classify arc ip4_unicast}
  * @cliexend
  * @endparblock
 ?*/
 /* *INDENT-OFF* */
 VLIB_CLI_COMMAND (set_interface_feature_command, static) = {
   .path = "set interface feature",
   .short_help = "set interface feature <intfc> <feature_name> arc <arc_name> "
       "[disable]",
   .function = set_interface_features_command_fn,
 };
 /* *INDENT-ON* */

 /*
  * fd.io coding-style-patch-verification: ON
  *
  * Local Variables:
  * eval: (c-set-style "gnu")
  * End:
  */
	/*
	* Copyright (c) 2016 Cisco and/or its affiliates.
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at:
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include <vnet/feature/feature.h>
	#include <vnet/adj/adj.h>

	vnet_feature_main_t feature_main;

	static clib_error_t *
	vnet_feature_init (vlib_main_t * vm)
	{
	vnet_feature_main_t *fm = &feature_main;
	vnet_feature_registration_t *freg;
	vnet_feature_arc_registration_t *areg;
	u32 arc_index = 0;

	fm->arc_index_by_name = hash_create_string (0, sizeof (uword));
	areg = fm->next_arc;

	/* process feature arc registrations */
	while (areg)
	{
	char *s;
	int i = 0;
	areg->feature_arc_index = arc_index;
	if (areg->arc_index_ptr)
	*areg->arc_index_ptr = arc_index;
	hash_set_mem (fm->arc_index_by_name, areg->arc_name,
	pointer_to_uword (areg));

	/* process start nodes */
	while ((s = areg->start_nodes[i]))
	{
	i++;
	}
	areg->n_start_nodes = i;

	/* next */
	areg = areg->next;
	arc_index++;
	}

	vec_validate (fm->next_feature_by_arc, arc_index - 1);
	vec_validate (fm->feature_nodes, arc_index - 1);
	vec_validate (fm->feature_config_mains, arc_index - 1);
	vec_validate (fm->next_feature_by_name, arc_index - 1);
	vec_validate (fm->sw_if_index_has_features, arc_index - 1);
	vec_validate (fm->feature_count_by_sw_if_index, arc_index - 1);

	freg = fm->next_feature;
	while (freg)
	{
	vnet_feature_registration_t *next;
	uword *p = hash_get_mem (fm->arc_index_by_name, freg->arc_name);
	if (p == 0)
	{
	/* Don't start vpp with broken features arcs */
	clib_warning ("Unknown feature arc '%s'", freg->arc_name);
	os_exit (1);
	}

	areg = uword_to_pointer (p[0], vnet_feature_arc_registration_t *);
	arc_index = areg->feature_arc_index;

	next = freg->next;
	freg->next = fm->next_feature_by_arc[arc_index];
	fm->next_feature_by_arc[arc_index] = freg;

	/* next */
	freg = next;
	}

	areg = fm->next_arc;
	while (areg)
	{
	clib_error_t *error;
	vnet_feature_config_main_t *cm;
	vnet_config_main_t *vcm;

	arc_index = areg->feature_arc_index;
	cm = &fm->feature_config_mains[arc_index];
	vcm = &cm->config_main;
	if ((error = vnet_feature_arc_init (vm, vcm,
	areg->start_nodes,
	areg->n_start_nodes,
	fm->next_feature_by_arc[arc_index],
	&fm->feature_nodes[arc_index])))
	{
	clib_error_report (error);
	os_exit (1);
	}

	fm->next_feature_by_name[arc_index] =
	hash_create_string (0, sizeof (uword));
	freg = fm->next_feature_by_arc[arc_index];

	while (freg)
	{
	hash_set_mem (fm->next_feature_by_name[arc_index],
	freg->node_name, pointer_to_uword (freg));
	freg = freg->next;
	}

	/* next */
	areg = areg->next;
	arc_index++;
	}

	return 0;
	}

	VLIB_INIT_FUNCTION (vnet_feature_init);

	u8
	vnet_get_feature_arc_index (const char *s)
	{
	vnet_feature_main_t *fm = &feature_main;
	vnet_feature_arc_registration_t *reg;
	uword *p;

	p = hash_get_mem (fm->arc_index_by_name, s);
	if (p == 0)
	return ~0;

	reg = uword_to_pointer (p[0], vnet_feature_arc_registration_t *);
	return reg->feature_arc_index;
	}

	vnet_feature_registration_t *
	vnet_get_feature_reg (const char arc_name, const char node_name)
	{
	u8 arc_index;

	arc_index = vnet_get_feature_arc_index (arc_name);
	if (arc_index == (u8) ~ 0)
	return 0;

	vnet_feature_main_t *fm = &feature_main;
	vnet_feature_registration_t *reg;
	uword *p;

	p = hash_get_mem (fm->next_feature_by_name[arc_index], node_name);
	if (p == 0)
	return 0;

	reg = uword_to_pointer (p[0], vnet_feature_registration_t *);
	return reg;
	}

	u32
	vnet_get_feature_index (u8 arc, const char *s)
	{
	vnet_feature_main_t *fm = &feature_main;
	vnet_feature_registration_t *reg;
	uword *p;

	if (s == 0)
	return ~0;

	p = hash_get_mem (fm->next_feature_by_name[arc], s);
	if (p == 0)
	return ~0;

	reg = uword_to_pointer (p[0], vnet_feature_registration_t *);
	return reg->feature_index;
	}

	int
	vnet_feature_enable_disable_with_index (u8 arc_index, u32 feature_index,
	u32 sw_if_index, int enable_disable,
	void *feature_config,
	u32 n_feature_config_bytes)
	{
	vnet_feature_main_t *fm = &feature_main;
	vnet_feature_config_main_t *cm;
	i16 feature_count;
	u32 ci;

	if (arc_index == (u8) ~ 0)
	return VNET_API_ERROR_INVALID_VALUE;

	if (feature_index == ~0)
	return VNET_API_ERROR_INVALID_VALUE_2;

	cm = &fm->feature_config_mains[arc_index];
	vec_validate_init_empty (cm->config_index_by_sw_if_index, sw_if_index, ~0);
	ci = cm->config_index_by_sw_if_index[sw_if_index];

	vec_validate (fm->feature_count_by_sw_if_index[arc_index], sw_if_index);
	feature_count = fm->feature_count_by_sw_if_index[arc_index][sw_if_index];

	if (!enable_disable && feature_count < 1)
	return 0;

	ci = (enable_disable
	? vnet_config_add_feature
	: vnet_config_del_feature)
	(vlib_get_main (), &cm->config_main, ci, feature_index, feature_config,
	n_feature_config_bytes);
	cm->config_index_by_sw_if_index[sw_if_index] = ci;

	/* update feature count */
	enable_disable = (enable_disable > 0);
	feature_count += enable_disable ? 1 : -1;
	ASSERT (feature_count >= 0);

	fm->sw_if_index_has_features[arc_index] =
	clib_bitmap_set (fm->sw_if_index_has_features[arc_index], sw_if_index,
	(feature_count > 0));
	adj_feature_update (sw_if_index, arc_index, (feature_count > 0));

	fm->feature_count_by_sw_if_index[arc_index][sw_if_index] = feature_count;
	return 0;
	}

	int
	vnet_feature_enable_disable (const char arc_name, const char node_name,
	u32 sw_if_index, int enable_disable,
	void *feature_config, u32 n_feature_config_bytes)
	{
	u32 feature_index;
	u8 arc_index;

	arc_index = vnet_get_feature_arc_index (arc_name);

	if (arc_index == (u8) ~ 0)
	return VNET_API_ERROR_INVALID_VALUE;

	feature_index = vnet_get_feature_index (arc_index, node_name);

	return vnet_feature_enable_disable_with_index (arc_index, feature_index,
	sw_if_index, enable_disable,
	feature_config,
	n_feature_config_bytes);
	}


	/** Display the set of available driver features.
	Useful for verifying that expected features are present
	*/

	static clib_error_t *
	show_features_command_fn (vlib_main_t * vm,
	unformat_input_t * input, vlib_cli_command_t * cmd)
	{
	vnet_feature_main_t *fm = &feature_main;
	vnet_feature_arc_registration_t *areg;
	vnet_feature_registration_t *freg;

	vlib_cli_output (vm, "Available feature paths");

	areg = fm->next_arc;
	while (areg)
	{
	vlib_cli_output (vm, "%s:", areg->arc_name);
	freg = fm->next_feature_by_arc[areg->feature_arc_index];
	while (freg)
	{
	vlib_cli_output (vm, " %s\n", freg->node_name);
	freg = freg->next;
	}


	/* next */
	areg = areg->next;
	}

	return 0;
	}

	/*?
	* Display the set of available driver features
	*
	* @cliexpar
	* Example:
	* @cliexcmd{show ip features}
	* @cliexend
	* @endparblock
	?*/
	/* INDENT-OFF */
	VLIB_CLI_COMMAND (show_features_command, static) = {
	.path = "show features",
	.short_help = "show features",
	.function = show_features_command_fn,
	};
	/* INDENT-ON */

	/** Display the set of driver features configured on a specific interface
	* Called by "show interface" handler
	*/

	void
	vnet_interface_features_show (vlib_main_t * vm, u32 sw_if_index)
	{
	vnet_feature_main_t *fm = &feature_main;
	u32 node_index, current_config_index;
	u16 feature_arc;
	vnet_feature_config_main_t *cm = fm->feature_config_mains;
	vnet_feature_arc_registration_t *areg;
	vnet_config_main_t *vcm;
	vnet_config_t *cfg;
	u32 cfg_index;
	vnet_config_feature_t *feat;
	vlib_node_t *n;
	int i;

	vlib_cli_output (vm, "Driver feature paths configured on %U...",
	format_vnet_sw_if_index_name,
	vnet_get_main (), sw_if_index);

	areg = fm->next_arc;
	while (areg)
	{
	feature_arc = areg->feature_arc_index;
	vcm = &(cm[feature_arc].config_main);

	vlib_cli_output (vm, "\n%s:", areg->arc_name);
	areg = areg->next;

	if (NULL == cm[feature_arc].config_index_by_sw_if_index \|\|
	vec_len (cm[feature_arc].config_index_by_sw_if_index) <=
	sw_if_index)
	{
	vlib_cli_output (vm, " none configured");
	continue;
	}

	current_config_index =
	vec_elt (cm[feature_arc].config_index_by_sw_if_index, sw_if_index);

	if (current_config_index == ~0)
	{
	vlib_cli_output (vm, " none configured");
	continue;
	}

	ASSERT (current_config_index
	< vec_len (vcm->config_pool_index_by_user_index));

	cfg_index = vcm->config_pool_index_by_user_index[current_config_index];
	cfg = pool_elt_at_index (vcm->config_pool, cfg_index);

	for (i = 0; i < vec_len (cfg->features); i++)
	{
	feat = cfg->features + i;
	node_index = feat->node_index;
	n = vlib_get_node (vm, node_index);
	vlib_cli_output (vm, " %v", n->name);
	}
	}
	}

	static clib_error_t *
	set_interface_features_command_fn (vlib_main_t * vm,
	unformat_input_t * input,
	vlib_cli_command_t * cmd)
	{
	vnet_main_t *vnm = vnet_get_main ();
	unformat_input_t _line_input, *line_input = &_line_input;
	clib_error_t *error = 0;

	u8 *arc_name = 0;
	u8 *feature_name = 0;
	u32 sw_if_index = ~0;
	u8 enable = 1;

	/* Get a line of input. */
	if (!unformat_user (input, unformat_line_input, line_input))
	goto done;

	while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT)
	{
	if (unformat
	(line_input, "%U %v", unformat_vnet_sw_interface, vnm, &sw_if_index,
	&feature_name))
	;
	else if (unformat (line_input, "arc %v", &arc_name))
	;
	else if (unformat (line_input, "disable"))
	enable = 0;
	else
	{
	error = unformat_parse_error (line_input);
	goto done;
	}
	}

	if (sw_if_index == ~0)
	{
	error = clib_error_return (0, "Interface not specified...");
	goto done;
	}

	vec_add1 (arc_name, 0);
	vec_add1 (feature_name, 0);

	vnet_feature_registration_t *reg;
	reg =
	vnet_get_feature_reg ((const char *) arc_name,
	(const char *) feature_name);
	if (reg == 0)
	{
	error = clib_error_return (0, "Unknown feature...");
	goto done;
	}
	if (reg->enable_disable_cb)
	error = reg->enable_disable_cb (sw_if_index, enable);
	if (!error)
	vnet_feature_enable_disable ((const char *) arc_name,
	(const char *) feature_name, sw_if_index,
	enable, 0, 0);

	done:
	vec_free (feature_name);
	vec_free (arc_name);
	unformat_free (line_input);
	return error;
	}

	/*?
	* Set feature for given interface
	*
	* @cliexpar
	* Example:
	* @cliexcmd{set interface feature GigabitEthernet2/0/0 ip4_flow_classify arc ip4_unicast}
	* @cliexend
	* @endparblock
	?*/
	/* INDENT-OFF */
	VLIB_CLI_COMMAND (set_interface_feature_command, static) = {
	.path = "set interface feature",
	.short_help = "set interface feature <intfc> <feature_name> arc <arc_name> "
	"[disable]",
	.function = set_interface_features_command_fn,
	};
	/* INDENT-ON */

	/*
	* fd.io coding-style-patch-verification: ON
	*
	* Local Variables:
	* eval: (c-set-style "gnu")
	* End:
	*/