BIER

- see draft-ietf-bier-mpls-encapsulation-10
- midpoint, head and tail functions
- supported payload protocols; IPv4 and IPv6 only.

Change-Id: I59d7363bb6fdfdce8e4016a68a9c8f5a5e5791cb
Signed-off-by: Neale Ranns <nranns@cisco.com>

1 files changed, 367 insertions, 0 deletions

diff --git a/src/vnet/bier/bier_lookup.c b/src/vnet/bier/bier_lookup.c
new file mode 100644
index 00000000000..4cf29f886e4
--- /dev/null
+++ b/src/vnet/bier/bier_lookup.c
@@ -0,0 +1,367 @@
+/*
+ * 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 maintining 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 recoed 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();
+
+    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)
+        {
+            bier_bit_mask_bucket_t buckets_copy[BIER_HDR_BUCKETS_256];
+            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)->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);
+                        vnet_buffer (b0)->ip.adj_index[VLIB_TX] = 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
+                         */
+                        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.
+             */
+            u8 num_cloned, clone;
+            u32 n_clones;
+
+            n_clones = vec_len(blm->blm_fmasks[thread_index]);
+
+            if (PREDICT_TRUE(0 != n_clones))
+            {
+                ASSERT(n_clones < 256);
+                num_cloned = vlib_buffer_clone(vm, bi0,
+                                               blm->blm_clones[thread_index],
+                                               n_clones, 128);
+
+                if (num_cloned != n_clones)
+                {
+                    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);
+
+                    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;
+
+                        vlib_trace_buffer (vm, node, next0, c0, 0);
+                        tr = vlib_add_trace (vm, node, c0, sizeof (*tr));
+                        tr->bt_index = bti0;
+                        tr->bfm_index = blm->blm_fmasks[thread_index][clone];
+
+                        c0->flags |= VLIB_BUFFER_IS_TRACED;
+                    }
+
+                    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++)
+    {
+        /*
+         *  4096 is the most we will ever need to support
+         * a Bit-Mask length of 4096
+         */
+        vec_validate(blm->blm_fmasks[thread_index], 4095);
+        vec_validate(blm->blm_clones[thread_index], 4095);
+    }
+
+    return 0;
+}
+
+VLIB_INIT_FUNCTION (bier_lookup_module_init);