src/vnet/bier/bier_lookup.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/buffer.h>
 #include <vnet/vnet.h>

 #include <vnet/bier/bier_fmask.h>
 #include <vnet/bier/bier_hdr_inlines.h>
 #include <vnet/bier/bier_table.h>
 #include <vnet/bier/bier_fmask.h>

 /**
  * Struct maintaining the per-worker thread data for BIER lookups
  */
 typedef struct bier_lookup_main_t_
 {
     /* per-cpu vector of cloned packets */
     u32 **blm_clones;
     /* per-cpu vector of BIER fmasks */
     u32 **blm_fmasks;
 } bier_lookup_main_t;

 /**
  * Single instance of the lookup main
  */
 static bier_lookup_main_t bier_lookup_main;

 static char * bier_lookup_error_strings[] = {
 #define bier_error(n,s) s,
 #include <vnet/bier/bier_lookup_error.def>
 #undef bier_error
 };

 /*
  * Keep these values sematically the same as BIER lookup
  */
 #define foreach_bier_lookup_next                \
     _(DROP, "bier-drop")                        \
     _(OUTPUT, "bier-output")

 typedef enum {
 #define _(s,n) BIER_LOOKUP_NEXT_##s,
     foreach_bier_lookup_next
 #undef _
     BIER_LOOKUP_N_NEXT,
 } bier_lookup_next_t;

 typedef enum {
 #define bier_error(n,s) BIER_LOOKUP_ERROR_##n,
 #include <vnet/bier/bier_lookup_error.def>
 #undef bier_error
     BIER_LOOKUP_N_ERROR,
 } bier_lookup_error_t;

 vlib_node_registration_t bier_lookup_node;

 /**
  * @brief Packet trace record for a BIER lookup
  */
 typedef struct bier_lookup_trace_t_
 {
     u32 next_index;
     index_t bt_index;
     index_t bfm_index;
 } bier_lookup_trace_t;

 static uword
 bier_lookup (vlib_main_t * vm,
              vlib_node_runtime_t * node,
              vlib_frame_t * from_frame)
 {
     u32 n_left_from, next_index, * from, * to_next;
     bier_lookup_main_t *blm = &bier_lookup_main;
     u32 thread_index = vlib_get_thread_index();
     bier_bit_mask_bucket_t buckets_copy[BIER_HDR_BUCKETS_4096];

     from = vlib_frame_vector_args (from_frame);
     n_left_from = from_frame->n_vectors;
     next_index = BIER_LOOKUP_NEXT_DROP;

     while (n_left_from > 0)
     {
         u32 n_left_to_next;

         vlib_get_next_frame (vm, node, next_index,
                              to_next, n_left_to_next);

         while (n_left_from > 0 && n_left_to_next > 0)
         {
             u32 next0, bi0, n_bytes, bti0, bfmi0;
             const bier_fmask_t *bfm0;
             const bier_table_t *bt0;
             u16 index, num_buckets;
             const bier_hdr_t *bh0;
             bier_bit_string_t bbs;
             vlib_buffer_t *b0;
             bier_bp_t fbs;
             int bucket;

             bi0 = from[0];
             from += 1;
             n_left_from -= 1;

             b0 = vlib_get_buffer (vm, bi0);
             bh0 = vlib_buffer_get_current (b0);
             bti0 = vnet_buffer(b0)->ip.adj_index[VLIB_TX];

             /*
              * default to drop so that if no bits are matched then
              * that is where we go - DROP.
              */
             next0 = BIER_LOOKUP_NEXT_DROP;

             /*
              * At the imposition or input node,
              * we stored the BIER Table index in the TX adjacency
              */
             bt0 = bier_table_get(vnet_buffer(b0)->ip.adj_index[VLIB_TX]);

             /*
              * we should only forward via one for the ECMP tables
              */
             ASSERT(!bier_table_is_main(bt0));

             /*
              * number of integer sized buckets
              */
             n_bytes = bier_hdr_len_id_to_num_buckets(bt0->bt_id.bti_hdr_len);
             vnet_buffer(b0)->mpls.bier.n_bytes = n_bytes;
             vnet_buffer(b0)->sw_if_index[VLIB_TX] = ~0;
             num_buckets = n_bytes / sizeof(int);
             bier_bit_string_init(&bbs,
                                  bt0->bt_id.bti_hdr_len,
                                  buckets_copy);
             memcpy(bbs.bbs_buckets, bh0->bh_bit_string, bbs.bbs_len);

             /*
              * reset the fmask and clone storage vectors
              */
             vec_reset_length (blm->blm_fmasks[thread_index]);
             vec_reset_length (blm->blm_clones[thread_index]);

             /*
              * Loop through the buckets in the header
              */
             for (index = 0; index < num_buckets; index++) {
                 /*
                  * loop through each bit in the bucket
                  */
                 bucket = ((int*)bbs.bbs_buckets)[index];

                 while (bucket) {
                     fbs  = bier_find_first_bit_string_set(bucket);
                     fbs += (((num_buckets - 1) - index) *
                             BIER_BIT_MASK_BITS_PER_INT);

                     bfmi0 = bier_table_fwd_lookup(bt0, fbs);

                     /*
                      * whatever happens, the bit we just looked for
                      * MUST be cleared from the packet
                      * otherwise we could be in this loop a while ...
                      */
                     bier_bit_string_clear_bit(&bbs, fbs);

                     if (PREDICT_TRUE(INDEX_INVALID != bfmi0))
                     {
                         bfm0 = bier_fmask_get(bfmi0);

                         /*
                          * use the bit-string on the fmask to reset
                          * the bits in the header we are walking
                          */
                         bier_bit_string_clear_string(
                             &bfm0->bfm_bits.bfmb_input_reset_string,
                             &bbs);
                         bucket = ((int*)bbs.bbs_buckets)[index];

                         /*
                          * the fmask is resolved so replicate a
                          * packet its way
                          */
                         next0 = BIER_LOOKUP_NEXT_OUTPUT;

                         vec_add1 (blm->blm_fmasks[thread_index], bfmi0);
                     } else {
                         /*
                          * go to the next bit-position set
                          */
                         vlib_node_increment_counter(
                             vm, node->node_index,
                             BIER_LOOKUP_ERROR_FMASK_UNRES, 1);
                         bucket = ((int*)bbs.bbs_buckets)[index];
                         continue;
                     }
                 }
             }

             /*
              * Full mask now processed.
              * Create the number of clones we need based on the number
              * of fmasks we are sending to.
              */
             u16 num_cloned, clone;
             u32 n_clones;

             n_clones = vec_len(blm->blm_fmasks[thread_index]);

             if (PREDICT_TRUE(0 != n_clones))
             {
                 num_cloned = vlib_buffer_clone(vm, bi0,
                                                blm->blm_clones[thread_index],
                                                n_clones,
 					       VLIB_BUFFER_CLONE_HEAD_SIZE);

                 if (num_cloned != vec_len(blm->blm_fmasks[thread_index]))
                 {
                     vlib_node_increment_counter
                         (vm, node->node_index,
                          BIER_LOOKUP_ERROR_BUFFER_ALLOCATION_FAILURE, 1);
                 }

                 for (clone = 0; clone < num_cloned; clone++)
                 {
                     vlib_buffer_t *c0;
                     u32 ci0;

                     ci0 = blm->blm_clones[thread_index][clone];
                     c0 = vlib_get_buffer(vm, ci0);
                     vnet_buffer(c0)->ip.adj_index[VLIB_TX] =
                         blm->blm_fmasks[thread_index][clone];

                     to_next[0] = ci0;
                     to_next += 1;
                     n_left_to_next -= 1;

                     if (PREDICT_FALSE(b0->flags & VLIB_BUFFER_IS_TRACED))
                     {
                         bier_lookup_trace_t *tr;

                         if (c0 != b0)
                             vlib_buffer_copy_trace_flag (vm, b0, ci0);

                         tr = vlib_add_trace (vm, node, c0, sizeof (*tr));
                         tr->bt_index = bti0;
                         tr->bfm_index = blm->blm_fmasks[thread_index][clone];
                     }

                     vlib_validate_buffer_enqueue_x1(vm, node, next_index,
                                                     to_next, n_left_to_next,
                                                     ci0, next0);

                     /*
                      * After the enqueue it is possible that we over-flow the
                      * frame of the to-next node. When this happens we need to
                      * 'put' that full frame to the node and get a fresh empty
                      * one. Note that these are macros with side effects that
                      * change to_next & n_left_to_next
                      */
                     if (PREDICT_FALSE(0 == n_left_to_next))
                     {
                         vlib_put_next_frame (vm, node, next_index,
                                              n_left_to_next);
                         vlib_get_next_frame (vm, node, next_index,
                                              to_next, n_left_to_next);
                     }
                 }
             }
             else
             {
                 /*
                  * no clones/replications required. drop this packet
                  */
                 next0 = BIER_LOOKUP_NEXT_DROP;
                 to_next[0] = bi0;
                 to_next += 1;
                 n_left_to_next -= 1;

                 if (PREDICT_FALSE(b0->flags & VLIB_BUFFER_IS_TRACED))
                 {
                     bier_lookup_trace_t *tr;

                     tr = vlib_add_trace (vm, node, b0, sizeof (*tr));

                     tr->bt_index = bti0;
                     tr->bfm_index = ~0;
                 }

                 vlib_validate_buffer_enqueue_x1(vm, node, next_index,
                                                 to_next, n_left_to_next,
                                                 bi0, next0);
             }
         }

         vlib_put_next_frame(vm, node, next_index, n_left_to_next);
     }

     vlib_node_increment_counter(vm, bier_lookup_node.index,
                                 BIER_LOOKUP_ERROR_NONE,
                                 from_frame->n_vectors);
     return (from_frame->n_vectors);
 }

 static u8 *
 format_bier_lookup_trace (u8 * s, va_list * args)
 {
     CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
     CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
     bier_lookup_trace_t * t = va_arg (*args, bier_lookup_trace_t *);

     s = format (s, "BIER: next [%d], tbl:%d BFM:%d",
                 t->next_index,
                 t->bt_index,
                 t->bfm_index);
     return s;
 }

 VLIB_REGISTER_NODE (bier_lookup_node) = {
     .function = bier_lookup,
     .name = "bier-lookup",
     /* Takes a vector of packets. */
     .vector_size = sizeof (u32),

     .n_errors = BIER_LOOKUP_N_ERROR,
     .error_strings = bier_lookup_error_strings,

     .format_trace = format_bier_lookup_trace,
     .n_next_nodes = BIER_LOOKUP_N_NEXT,
     .next_nodes = {
         [BIER_LOOKUP_NEXT_DROP] = "bier-drop",
         [BIER_LOOKUP_NEXT_OUTPUT] = "bier-output",
     },
 };

 clib_error_t *
 bier_lookup_module_init (vlib_main_t * vm)
 {
     bier_lookup_main_t *blm = &bier_lookup_main;
     u32 thread_index;

     vec_validate (blm->blm_clones, vlib_num_workers());
     vec_validate (blm->blm_fmasks, vlib_num_workers());

     for (thread_index = 0;
          thread_index <= vlib_num_workers();
          thread_index++)
     {
         /*
          *  1024 is the most we will ever need to support
          * a Bit-Mask length of 1024
          */
         vec_validate(blm->blm_fmasks[thread_index], 1023);
         vec_validate(blm->blm_clones[thread_index], 1023);
     }

     return 0;
 }

 VLIB_INIT_FUNCTION (bier_lookup_module_init);
	/*
	* 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/buffer.h>
	#include <vnet/vnet.h>

	#include <vnet/bier/bier_fmask.h>
	#include <vnet/bier/bier_hdr_inlines.h>
	#include <vnet/bier/bier_table.h>
	#include <vnet/bier/bier_fmask.h>

	/**
	* Struct maintaining the per-worker thread data for BIER lookups
	*/
	typedef struct bier_lookup_main_t_
	{
	/* per-cpu vector of cloned packets */
	u32 **blm_clones;
	/* per-cpu vector of BIER fmasks */
	u32 **blm_fmasks;
	} bier_lookup_main_t;

	/**
	* Single instance of the lookup main
	*/
	static bier_lookup_main_t bier_lookup_main;

	static char * bier_lookup_error_strings[] = {
	#define bier_error(n,s) s,
	#include <vnet/bier/bier_lookup_error.def>
	#undef bier_error
	};

	/*
	* Keep these values sematically the same as BIER lookup
	*/
	#define foreach_bier_lookup_next \
	_(DROP, "bier-drop") \
	_(OUTPUT, "bier-output")

	typedef enum {
	#define _(s,n) BIER_LOOKUP_NEXT_##s,
	foreach_bier_lookup_next
	#undef _
	BIER_LOOKUP_N_NEXT,
	} bier_lookup_next_t;

	typedef enum {
	#define bier_error(n,s) BIER_LOOKUP_ERROR_##n,
	#include <vnet/bier/bier_lookup_error.def>
	#undef bier_error
	BIER_LOOKUP_N_ERROR,
	} bier_lookup_error_t;

	vlib_node_registration_t bier_lookup_node;

	/**
	* @brief Packet trace record for a BIER lookup
	*/
	typedef struct bier_lookup_trace_t_
	{
	u32 next_index;
	index_t bt_index;
	index_t bfm_index;
	} bier_lookup_trace_t;

	static uword
	bier_lookup (vlib_main_t * vm,
	vlib_node_runtime_t * node,
	vlib_frame_t * from_frame)
	{
	u32 n_left_from, next_index, * from, * to_next;
	bier_lookup_main_t *blm = &bier_lookup_main;
	u32 thread_index = vlib_get_thread_index();
	bier_bit_mask_bucket_t buckets_copy[BIER_HDR_BUCKETS_4096];

	from = vlib_frame_vector_args (from_frame);
	n_left_from = from_frame->n_vectors;
	next_index = BIER_LOOKUP_NEXT_DROP;

	while (n_left_from > 0)
	{
	u32 n_left_to_next;

	vlib_get_next_frame (vm, node, next_index,
	to_next, n_left_to_next);

	while (n_left_from > 0 && n_left_to_next > 0)
	{
	u32 next0, bi0, n_bytes, bti0, bfmi0;
	const bier_fmask_t *bfm0;
	const bier_table_t *bt0;
	u16 index, num_buckets;
	const bier_hdr_t *bh0;
	bier_bit_string_t bbs;
	vlib_buffer_t *b0;
	bier_bp_t fbs;
	int bucket;

	bi0 = from[0];
	from += 1;
	n_left_from -= 1;

	b0 = vlib_get_buffer (vm, bi0);
	bh0 = vlib_buffer_get_current (b0);
	bti0 = vnet_buffer(b0)->ip.adj_index[VLIB_TX];

	/*
	* default to drop so that if no bits are matched then
	* that is where we go - DROP.
	*/
	next0 = BIER_LOOKUP_NEXT_DROP;

	/*
	* At the imposition or input node,
	* we stored the BIER Table index in the TX adjacency
	*/
	bt0 = bier_table_get(vnet_buffer(b0)->ip.adj_index[VLIB_TX]);

	/*
	* we should only forward via one for the ECMP tables
	*/
	ASSERT(!bier_table_is_main(bt0));

	/*
	* number of integer sized buckets
	*/
	n_bytes = bier_hdr_len_id_to_num_buckets(bt0->bt_id.bti_hdr_len);
	vnet_buffer(b0)->mpls.bier.n_bytes = n_bytes;
	vnet_buffer(b0)->sw_if_index[VLIB_TX] = ~0;
	num_buckets = n_bytes / sizeof(int);
	bier_bit_string_init(&bbs,
	bt0->bt_id.bti_hdr_len,
	buckets_copy);
	memcpy(bbs.bbs_buckets, bh0->bh_bit_string, bbs.bbs_len);

	/*
	* reset the fmask and clone storage vectors
	*/
	vec_reset_length (blm->blm_fmasks[thread_index]);
	vec_reset_length (blm->blm_clones[thread_index]);

	/*
	* Loop through the buckets in the header
	*/
	for (index = 0; index < num_buckets; index++) {
	/*
	* loop through each bit in the bucket
	*/
	bucket = ((int*)bbs.bbs_buckets)[index];

	while (bucket) {
	fbs = bier_find_first_bit_string_set(bucket);
	fbs += (((num_buckets - 1) - index) *
	BIER_BIT_MASK_BITS_PER_INT);

	bfmi0 = bier_table_fwd_lookup(bt0, fbs);

	/*
	* whatever happens, the bit we just looked for
	* MUST be cleared from the packet
	* otherwise we could be in this loop a while ...
	*/
	bier_bit_string_clear_bit(&bbs, fbs);

	if (PREDICT_TRUE(INDEX_INVALID != bfmi0))
	{
	bfm0 = bier_fmask_get(bfmi0);

	/*
	* use the bit-string on the fmask to reset
	* the bits in the header we are walking
	*/
	bier_bit_string_clear_string(
	&bfm0->bfm_bits.bfmb_input_reset_string,
	&bbs);
	bucket = ((int*)bbs.bbs_buckets)[index];

	/*
	* the fmask is resolved so replicate a
	* packet its way
	*/
	next0 = BIER_LOOKUP_NEXT_OUTPUT;

	vec_add1 (blm->blm_fmasks[thread_index], bfmi0);
	} else {
	/*
	* go to the next bit-position set
	*/
	vlib_node_increment_counter(
	vm, node->node_index,
	BIER_LOOKUP_ERROR_FMASK_UNRES, 1);
	bucket = ((int*)bbs.bbs_buckets)[index];
	continue;
	}
	}
	}

	/*
	* Full mask now processed.
	* Create the number of clones we need based on the number
	* of fmasks we are sending to.
	*/
	u16 num_cloned, clone;
	u32 n_clones;

	n_clones = vec_len(blm->blm_fmasks[thread_index]);

	if (PREDICT_TRUE(0 != n_clones))
	{
	num_cloned = vlib_buffer_clone(vm, bi0,
	blm->blm_clones[thread_index],
	n_clones,
	VLIB_BUFFER_CLONE_HEAD_SIZE);

	if (num_cloned != vec_len(blm->blm_fmasks[thread_index]))
	{
	vlib_node_increment_counter
	(vm, node->node_index,
	BIER_LOOKUP_ERROR_BUFFER_ALLOCATION_FAILURE, 1);
	}

	for (clone = 0; clone < num_cloned; clone++)
	{
	vlib_buffer_t *c0;
	u32 ci0;

	ci0 = blm->blm_clones[thread_index][clone];
	c0 = vlib_get_buffer(vm, ci0);
	vnet_buffer(c0)->ip.adj_index[VLIB_TX] =
	blm->blm_fmasks[thread_index][clone];

	to_next[0] = ci0;
	to_next += 1;
	n_left_to_next -= 1;

	if (PREDICT_FALSE(b0->flags & VLIB_BUFFER_IS_TRACED))
	{
	bier_lookup_trace_t *tr;

	if (c0 != b0)
	vlib_buffer_copy_trace_flag (vm, b0, ci0);

	tr = vlib_add_trace (vm, node, c0, sizeof (*tr));
	tr->bt_index = bti0;
	tr->bfm_index = blm->blm_fmasks[thread_index][clone];
	}

	vlib_validate_buffer_enqueue_x1(vm, node, next_index,
	to_next, n_left_to_next,
	ci0, next0);

	/*
	* After the enqueue it is possible that we over-flow the
	* frame of the to-next node. When this happens we need to
	* 'put' that full frame to the node and get a fresh empty
	* one. Note that these are macros with side effects that
	* change to_next & n_left_to_next
	*/
	if (PREDICT_FALSE(0 == n_left_to_next))
	{
	vlib_put_next_frame (vm, node, next_index,
	n_left_to_next);
	vlib_get_next_frame (vm, node, next_index,
	to_next, n_left_to_next);
	}
	}
	}
	else
	{
	/*
	* no clones/replications required. drop this packet
	*/
	next0 = BIER_LOOKUP_NEXT_DROP;
	to_next[0] = bi0;
	to_next += 1;
	n_left_to_next -= 1;

	if (PREDICT_FALSE(b0->flags & VLIB_BUFFER_IS_TRACED))
	{
	bier_lookup_trace_t *tr;

	tr = vlib_add_trace (vm, node, b0, sizeof (*tr));

	tr->bt_index = bti0;
	tr->bfm_index = ~0;
	}

	vlib_validate_buffer_enqueue_x1(vm, node, next_index,
	to_next, n_left_to_next,
	bi0, next0);
	}
	}

	vlib_put_next_frame(vm, node, next_index, n_left_to_next);
	}

	vlib_node_increment_counter(vm, bier_lookup_node.index,
	BIER_LOOKUP_ERROR_NONE,
	from_frame->n_vectors);
	return (from_frame->n_vectors);
	}

	static u8 *
	format_bier_lookup_trace (u8 * s, va_list * args)
	{
	CLIB_UNUSED (vlib_main_t * vm) = va_arg (args, vlib_main_t );
	CLIB_UNUSED (vlib_node_t * node) = va_arg (args, vlib_node_t );
	bier_lookup_trace_t * t = va_arg (args, bier_lookup_trace_t );

	s = format (s, "BIER: next [%d], tbl:%d BFM:%d",
	t->next_index,
	t->bt_index,
	t->bfm_index);
	return s;
	}

	VLIB_REGISTER_NODE (bier_lookup_node) = {
	.function = bier_lookup,
	.name = "bier-lookup",
	/* Takes a vector of packets. */
	.vector_size = sizeof (u32),

	.n_errors = BIER_LOOKUP_N_ERROR,
	.error_strings = bier_lookup_error_strings,

	.format_trace = format_bier_lookup_trace,
	.n_next_nodes = BIER_LOOKUP_N_NEXT,
	.next_nodes = {
	[BIER_LOOKUP_NEXT_DROP] = "bier-drop",
	[BIER_LOOKUP_NEXT_OUTPUT] = "bier-output",
	},
	};

	clib_error_t *
	bier_lookup_module_init (vlib_main_t * vm)
	{
	bier_lookup_main_t *blm = &bier_lookup_main;
	u32 thread_index;

	vec_validate (blm->blm_clones, vlib_num_workers());
	vec_validate (blm->blm_fmasks, vlib_num_workers());

	for (thread_index = 0;
	thread_index <= vlib_num_workers();
	thread_index++)
	{
	/*
	* 1024 is the most we will ever need to support
	* a Bit-Mask length of 1024
	*/
	vec_validate(blm->blm_fmasks[thread_index], 1023);
	vec_validate(blm->blm_clones[thread_index], 1023);
	}

	return 0;
	}

	VLIB_INIT_FUNCTION (bier_lookup_module_init);