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-rw-r--r--vnet/vnet/l2/l2_learn.c504
1 files changed, 504 insertions, 0 deletions
diff --git a/vnet/vnet/l2/l2_learn.c b/vnet/vnet/l2/l2_learn.c
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+/*
+ * l2_learn.c : layer 2 learning using l2fib
+ *
+ * Copyright (c) 2013 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 <vlib/vlib.h>
+#include <vnet/vnet.h>
+#include <vnet/pg/pg.h>
+#include <vnet/ethernet/ethernet.h>
+#include <vlib/cli.h>
+
+#include <vnet/l2/l2_input.h>
+#include <vnet/l2/feat_bitmap.h>
+#include <vnet/l2/l2_fib.h>
+#include <vnet/l2/l2_learn.h>
+
+#include <vppinfra/error.h>
+#include <vppinfra/hash.h>
+
+/*
+ * Ethernet bridge learning
+ *
+ * Populate the mac table with entries mapping the packet's source mac + bridge
+ * domain ID to the input sw_if_index.
+ *
+ * Note that learning and forwarding are separate graph nodes. This means that
+ * for a set of packets, all learning is performed first, then all nodes are
+ * forwarded. The forwarding is done based on the end-state of the mac table,
+ * instead of the state after each packet. Thus the forwarding results could
+ * differ in certain cases (mac move tests), but this not expected to cause
+ * problems in real-world networks. It is much simpler to separate learning
+ * and forwarding into separate nodes.
+ */
+
+
+typedef struct {
+ u8 src[6];
+ u8 dst[6];
+ u32 sw_if_index;
+ u16 bd_index;
+} l2learn_trace_t;
+
+
+/* packet trace format function */
+static u8 * format_l2learn_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 *);
+ l2learn_trace_t * t = va_arg (*args, l2learn_trace_t *);
+
+ s = format (s, "l2-learn: sw_if_index %d dst %U src %U bd_index %d",
+ t->sw_if_index,
+ format_ethernet_address, t->dst,
+ format_ethernet_address, t->src,
+ t->bd_index);
+ return s;
+}
+
+static vlib_node_registration_t l2learn_node;
+
+#define foreach_l2learn_error \
+_(L2LEARN, "L2 learn packets") \
+_(MISS, "L2 learn misses") \
+_(MAC_MOVE, "L2 mac moves") \
+_(MAC_MOVE_VIOLATE, "L2 mac move violations") \
+_(LIMIT, "L2 not learned due to limit") \
+_(HIT, "L2 learn hits") \
+_(FILTER_DROP, "L2 filter mac drops")
+
+typedef enum {
+#define _(sym,str) L2LEARN_ERROR_##sym,
+ foreach_l2learn_error
+#undef _
+ L2LEARN_N_ERROR,
+} l2learn_error_t;
+
+static char * l2learn_error_strings[] = {
+#define _(sym,string) string,
+ foreach_l2learn_error
+#undef _
+};
+
+typedef enum {
+ L2LEARN_NEXT_L2FWD,
+ L2LEARN_NEXT_DROP,
+ L2LEARN_N_NEXT,
+} l2learn_next_t;
+
+
+// Perform learning on one packet based on the mac table lookup result
+
+static_always_inline void
+l2learn_process (vlib_node_runtime_t * node,
+ l2learn_main_t * msm,
+ u64 * counter_base,
+ vlib_buffer_t * b0,
+ u32 sw_if_index0,
+ l2fib_entry_key_t * key0,
+ l2fib_entry_key_t * cached_key,
+ u32 * bucket0,
+ l2fib_entry_result_t * result0,
+ u32 * next0)
+{
+ u32 feature_bitmap;
+
+ // Set up the default next node (typically L2FWD)
+
+ // Remove ourself from the feature bitmap
+ feature_bitmap = vnet_buffer(b0)->l2.feature_bitmap & ~L2INPUT_FEAT_LEARN;
+
+ // Save for next feature graph nodes
+ vnet_buffer(b0)->l2.feature_bitmap = feature_bitmap;
+
+ // Determine the next node
+ *next0 = feat_bitmap_get_next_node_index(msm->feat_next_node_index,
+ feature_bitmap);
+
+ // Check mac table lookup result
+
+ if (PREDICT_TRUE (result0->fields.sw_if_index == sw_if_index0)) {
+ // The entry was in the table, and the sw_if_index matched, the normal case
+
+ // TODO: for dataplane learning and aging, do this:
+ // if refresh=0 and not a static mac, set refresh=1
+ counter_base[L2LEARN_ERROR_HIT] += 1;
+
+ } else if (result0->raw == ~0) {
+
+ // The entry was not in table, so add it
+
+ counter_base[L2LEARN_ERROR_MISS] += 1;
+
+ if (msm->global_learn_count == msm->global_learn_limit) {
+ // Global limit reached. Do not learn the mac but forward the packet.
+ // In the future, limits could also be per-interface or bridge-domain.
+ counter_base[L2LEARN_ERROR_LIMIT] += 1;
+ goto done;
+
+ } else {
+ BVT(clib_bihash_kv) kv;
+ // It is ok to learn
+
+ result0->raw = 0; // clear all fields
+ result0->fields.sw_if_index = sw_if_index0;
+ // TODO: set timestamp in entry to clock for dataplane aging
+ kv.key = key0->raw;
+ kv.value = result0->raw;
+
+ BV(clib_bihash_add_del) (msm->mac_table, &kv, 1 /* is_add */);
+
+ cached_key->raw = ~0; // invalidate the cache
+ msm->global_learn_count++;
+ }
+
+ } else {
+
+ // The entry was in the table, but with the wrong sw_if_index mapping (mac move)
+ counter_base[L2LEARN_ERROR_MAC_MOVE] += 1;
+
+ if (result0->fields.static_mac) {
+ // Don't overwrite a static mac
+ // TODO: Check violation policy. For now drop the packet
+ b0->error = node->errors[L2LEARN_ERROR_MAC_MOVE_VIOLATE];
+ *next0 = L2LEARN_NEXT_DROP;
+ } else {
+ // Update the entry
+ // TODO: may want to rate limit mac moves
+ // TODO: check global/bridge domain/interface learn limits
+ BVT(clib_bihash_kv) kv;
+
+ result0->raw = 0; // clear all fields
+ result0->fields.sw_if_index = sw_if_index0;
+
+ kv.key = key0->raw;
+ kv.value = result0->raw;
+
+ cached_key->raw = ~0; // invalidate the cache
+
+ BV(clib_bihash_add_del) (msm->mac_table, &kv, 1 /* is_add */);
+ }
+ }
+
+ if (result0->fields.filter) {
+ // drop packet because lookup matched a filter mac entry
+
+ if (*next0 != L2LEARN_NEXT_DROP) {
+ // if we're not already dropping the packet, do it now
+ b0->error = node->errors[L2LEARN_ERROR_FILTER_DROP];
+ *next0 = L2LEARN_NEXT_DROP;
+ }
+ }
+
+done:
+ return;
+}
+
+
+static uword
+l2learn_node_fn (vlib_main_t * vm,
+ vlib_node_runtime_t * node,
+ vlib_frame_t * frame)
+{
+ u32 n_left_from, * from, * to_next;
+ l2learn_next_t next_index;
+ l2learn_main_t * msm = &l2learn_main;
+ vlib_node_t *n = vlib_get_node (vm, l2learn_node.index);
+ u32 node_counter_base_index = n->error_heap_index;
+ vlib_error_main_t * em = &vm->error_main;
+ l2fib_entry_key_t cached_key;
+ l2fib_entry_result_t cached_result;
+
+ from = vlib_frame_vector_args (frame);
+ n_left_from = frame->n_vectors; /* number of packets to process */
+ next_index = node->cached_next_index;
+
+ // Clear the one-entry cache in case mac table was updated
+ cached_key.raw = ~0;
+ cached_result.raw = ~0; /* warning be gone */
+
+ while (n_left_from > 0)
+ {
+ u32 n_left_to_next;
+
+ /* get space to enqueue frame to graph node "next_index" */
+ vlib_get_next_frame (vm, node, next_index,
+ to_next, n_left_to_next);
+
+ while (n_left_from >= 4 && n_left_to_next >= 2)
+ {
+ u32 bi0, bi1;
+ vlib_buffer_t * b0, * b1;
+ u32 next0, next1;
+ u32 sw_if_index0, sw_if_index1;
+ ethernet_header_t * h0, * h1;
+ l2fib_entry_key_t key0, key1;
+ l2fib_entry_result_t result0, result1;
+ u32 bucket0, bucket1;
+
+ /* Prefetch next iteration. */
+ {
+ vlib_buffer_t * p2, * p3;
+
+ p2 = vlib_get_buffer (vm, from[2]);
+ p3 = vlib_get_buffer (vm, from[3]);
+
+ vlib_prefetch_buffer_header (p2, LOAD);
+ vlib_prefetch_buffer_header (p3, LOAD);
+
+ CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE);
+ CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, STORE);
+ }
+
+ /* speculatively enqueue b0 and b1 to the current next frame */
+ /* bi is "buffer index", b is pointer to the buffer */
+ to_next[0] = bi0 = from[0];
+ to_next[1] = bi1 = from[1];
+ from += 2;
+ to_next += 2;
+ n_left_from -= 2;
+ n_left_to_next -= 2;
+
+ b0 = vlib_get_buffer (vm, bi0);
+ b1 = vlib_get_buffer (vm, bi1);
+
+ /* RX interface handles */
+ sw_if_index0 = vnet_buffer(b0)->sw_if_index[VLIB_RX];
+ sw_if_index1 = vnet_buffer(b1)->sw_if_index[VLIB_RX];
+
+ /* Process 2 x pkts */
+
+ h0 = vlib_buffer_get_current (b0);
+ h1 = vlib_buffer_get_current (b1);
+
+ if (PREDICT_FALSE((node->flags & VLIB_NODE_FLAG_TRACE)))
+ {
+ if (b0->flags & VLIB_BUFFER_IS_TRACED)
+ {
+ l2learn_trace_t *t =
+ vlib_add_trace (vm, node, b0, sizeof (*t));
+ t->sw_if_index = sw_if_index0;
+ t->bd_index = vnet_buffer(b0)->l2.bd_index;
+ memcpy(t->src, h0->src_address, 6);
+ memcpy(t->dst, h0->dst_address, 6);
+ }
+ if (b1->flags & VLIB_BUFFER_IS_TRACED)
+ {
+ l2learn_trace_t *t =
+ vlib_add_trace (vm, node, b1, sizeof (*t));
+ t->sw_if_index = sw_if_index1;
+ t->bd_index = vnet_buffer(b1)->l2.bd_index;
+ memcpy(t->src, h1->src_address, 6);
+ memcpy(t->dst, h1->dst_address, 6);
+ }
+ }
+
+ /* process 2 pkts */
+ em->counters[node_counter_base_index + L2LEARN_ERROR_L2LEARN] += 2;
+
+ l2fib_lookup_2 (msm->mac_table, &cached_key, &cached_result,
+ h0->src_address,
+ h1->src_address,
+ vnet_buffer(b0)->l2.bd_index,
+ vnet_buffer(b1)->l2.bd_index,
+ &key0,
+ &key1,
+ &bucket0,
+ &bucket1,
+ &result0,
+ &result1);
+
+ l2learn_process (node, msm, &em->counters[node_counter_base_index],
+ b0, sw_if_index0, &key0, &cached_key,
+ &bucket0, &result0, &next0);
+
+ l2learn_process (node, msm, &em->counters[node_counter_base_index],
+ b1, sw_if_index1, &key1, &cached_key,
+ &bucket1, &result1, &next1);
+
+ /* verify speculative enqueues, maybe switch current next frame */
+ /* if next0==next1==next_index then nothing special needs to be done */
+ vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
+ to_next, n_left_to_next,
+ bi0, bi1, next0, next1);
+ }
+
+ while (n_left_from > 0 && n_left_to_next > 0)
+ {
+ u32 bi0;
+ vlib_buffer_t * b0;
+ u32 next0;
+ u32 sw_if_index0;
+ ethernet_header_t * h0;
+ l2fib_entry_key_t key0;
+ l2fib_entry_result_t result0;
+ u32 bucket0;
+
+ /* speculatively enqueue b0 to the current next frame */
+ bi0 = from[0];
+ to_next[0] = bi0;
+ from += 1;
+ to_next += 1;
+ n_left_from -= 1;
+ n_left_to_next -= 1;
+
+ b0 = vlib_get_buffer (vm, bi0);
+
+ sw_if_index0 = vnet_buffer(b0)->sw_if_index[VLIB_RX];
+
+ h0 = vlib_buffer_get_current (b0);
+
+ if (PREDICT_FALSE((node->flags & VLIB_NODE_FLAG_TRACE)
+ && (b0->flags & VLIB_BUFFER_IS_TRACED))) {
+ l2learn_trace_t *t =
+ vlib_add_trace (vm, node, b0, sizeof (*t));
+ t->sw_if_index = sw_if_index0;
+ t->bd_index = vnet_buffer(b0)->l2.bd_index;
+ memcpy(t->src, h0->src_address, 6);
+ memcpy(t->dst, h0->dst_address, 6);
+ }
+
+ /* process 1 pkt */
+ em->counters[node_counter_base_index + L2LEARN_ERROR_L2LEARN] += 1;
+
+ l2fib_lookup_1 (msm->mac_table, &cached_key, &cached_result,
+ h0->src_address, vnet_buffer(b0)->l2.bd_index,
+ &key0,
+ &bucket0,
+ &result0);
+
+ l2learn_process (node, msm, &em->counters[node_counter_base_index],
+ b0, sw_if_index0, &key0, &cached_key,
+ &bucket0, &result0, &next0);
+
+ /* verify speculative enqueue, maybe switch current next frame */
+ 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);
+ }
+
+ return frame->n_vectors;
+}
+
+
+VLIB_REGISTER_NODE (l2learn_node,static) = {
+ .function = l2learn_node_fn,
+ .name = "l2-learn",
+ .vector_size = sizeof (u32),
+ .format_trace = format_l2learn_trace,
+ .type = VLIB_NODE_TYPE_INTERNAL,
+
+ .n_errors = ARRAY_LEN(l2learn_error_strings),
+ .error_strings = l2learn_error_strings,
+
+ .n_next_nodes = L2LEARN_N_NEXT,
+
+ /* edit / add dispositions here */
+ .next_nodes = {
+ [L2LEARN_NEXT_DROP] = "error-drop",
+ [L2LEARN_NEXT_L2FWD] = "l2-fwd",
+ },
+};
+
+
+clib_error_t *l2learn_init (vlib_main_t *vm)
+{
+ l2learn_main_t * mp = &l2learn_main;
+
+ mp->vlib_main = vm;
+ mp->vnet_main = vnet_get_main();
+
+ // Initialize the feature next-node indexes
+ feat_bitmap_init_next_nodes(vm,
+ l2learn_node.index,
+ L2INPUT_N_FEAT,
+ l2input_get_feat_names(),
+ mp->feat_next_node_index);
+
+ /* init the hash table ptr */
+ mp->mac_table = get_mac_table();
+
+ // Set the default number of dynamically learned macs to the number
+ // of buckets.
+ mp->global_learn_limit = L2FIB_NUM_BUCKETS * 16;
+
+ return 0;
+}
+
+VLIB_INIT_FUNCTION (l2learn_init);
+
+
+// set subinterface learn enable/disable
+// The CLI format is:
+// set interface l2 learn <interface> [disable]
+static clib_error_t *
+int_learn (vlib_main_t * vm,
+ unformat_input_t * input,
+ vlib_cli_command_t * cmd)
+{
+ vnet_main_t * vnm = vnet_get_main();
+ clib_error_t * error = 0;
+ u32 sw_if_index;
+ u32 enable;
+
+ if (! unformat_user (input, unformat_vnet_sw_interface, vnm, &sw_if_index))
+ {
+ error = clib_error_return (0, "unknown interface `%U'",
+ format_unformat_error, input);
+ goto done;
+ }
+
+ enable = 1;
+ if (unformat (input, "disable")) {
+ enable = 0;
+ }
+
+ // set the interface flag
+ l2input_intf_bitmap_enable(sw_if_index, L2INPUT_FEAT_LEARN, enable);
+
+ done:
+ return error;
+}
+
+VLIB_CLI_COMMAND (int_learn_cli, static) = {
+ .path = "set interface l2 learn",
+ .short_help = "set interface l2 learn <interface> [disable]",
+ .function = int_learn,
+};
+
+
+static clib_error_t *
+l2learn_config (vlib_main_t * vm, unformat_input_t * input)
+{
+ l2learn_main_t *mp = &l2learn_main;
+
+ while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+ {
+ if (unformat (input, "limit %d", &mp->global_learn_limit))
+ ;
+
+ else
+ return clib_error_return (0, "unknown input `%U'",
+ format_unformat_error, input);
+ }
+
+ return 0;
+}
+
+VLIB_CONFIG_FUNCTION (l2learn_config, "l2learn");
+