2 * l2_learn.c : layer 2 learning using l2fib
4 * Copyright (c) 2013 Cisco and/or its affiliates.
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at:
9 * http://www.apache.org/licenses/LICENSE-2.0
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
18 #include <vlib/vlib.h>
19 #include <vnet/vnet.h>
20 #include <vnet/pg/pg.h>
21 #include <vnet/ethernet/ethernet.h>
24 #include <vnet/l2/l2_input.h>
25 #include <vnet/l2/feat_bitmap.h>
26 #include <vnet/l2/l2_fib.h>
27 #include <vnet/l2/l2_learn.h>
29 #include <vppinfra/error.h>
30 #include <vppinfra/hash.h>
34 * @brief Ethernet Bridge Learning.
36 * Populate the mac table with entries mapping the packet's source mac + bridge
37 * domain ID to the input sw_if_index.
39 * Note that learning and forwarding are separate graph nodes. This means that
40 * for a set of packets, all learning is performed first, then all nodes are
41 * forwarded. The forwarding is done based on the end-state of the mac table,
42 * instead of the state after each packet. Thus the forwarding results could
43 * differ in certain cases (mac move tests), but this not expected to cause
44 * problems in real-world networks. It is much simpler to separate learning
45 * and forwarding into separate nodes.
58 /* packet trace format function */
60 format_l2learn_trace (u8 * s, va_list * args)
62 CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
63 CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
64 l2learn_trace_t *t = va_arg (*args, l2learn_trace_t *);
66 s = format (s, "l2-learn: sw_if_index %d dst %U src %U bd_index %d",
68 format_ethernet_address, t->dst,
69 format_ethernet_address, t->src, t->bd_index);
73 static vlib_node_registration_t l2learn_node;
75 #define foreach_l2learn_error \
76 _(L2LEARN, "L2 learn packets") \
77 _(MISS, "L2 learn misses") \
78 _(MAC_MOVE, "L2 mac moves") \
79 _(MAC_MOVE_VIOLATE, "L2 mac move violations") \
80 _(LIMIT, "L2 not learned due to limit") \
81 _(HIT, "L2 learn hits") \
82 _(FILTER_DROP, "L2 filter mac drops")
86 #define _(sym,str) L2LEARN_ERROR_##sym,
92 static char *l2learn_error_strings[] = {
93 #define _(sym,string) string,
106 /** Perform learning on one packet based on the mac table lookup result. */
108 static_always_inline void
109 l2learn_process (vlib_node_runtime_t * node,
110 l2learn_main_t * msm,
114 l2fib_entry_key_t * key0,
115 l2fib_entry_key_t * cached_key,
117 l2fib_entry_result_t * result0, u32 * next0, u8 timestamp)
121 /* Set up the default next node (typically L2FWD) */
123 /* Remove ourself from the feature bitmap */
124 feature_bitmap = vnet_buffer (b0)->l2.feature_bitmap & ~L2INPUT_FEAT_LEARN;
126 /* Save for next feature graph nodes */
127 vnet_buffer (b0)->l2.feature_bitmap = feature_bitmap;
129 /* Determine the next node */
130 *next0 = feat_bitmap_get_next_node_index (msm->feat_next_node_index,
133 /* Check mac table lookup result */
135 if (PREDICT_TRUE (result0->fields.sw_if_index == sw_if_index0))
138 * The entry was in the table, and the sw_if_index matched, the normal case
140 counter_base[L2LEARN_ERROR_HIT] += 1;
141 if (PREDICT_FALSE (result0->fields.timestamp != timestamp))
142 result0->fields.timestamp = timestamp;
145 else if (result0->raw == ~0)
148 /* The entry was not in table, so add it */
150 counter_base[L2LEARN_ERROR_MISS] += 1;
152 if (msm->global_learn_count == msm->global_learn_limit)
155 * Global limit reached. Do not learn the mac but forward the packet.
156 * In the future, limits could also be per-interface or bridge-domain.
158 counter_base[L2LEARN_ERROR_LIMIT] += 1;
164 BVT (clib_bihash_kv) kv;
165 /* It is ok to learn */
167 result0->raw = 0; /* clear all fields */
168 result0->fields.sw_if_index = sw_if_index0;
169 result0->fields.timestamp = timestamp;
171 kv.value = result0->raw;
173 BV (clib_bihash_add_del) (msm->mac_table, &kv, 1 /* is_add */ );
175 cached_key->raw = ~0; /* invalidate the cache */
176 msm->global_learn_count++;
183 /* The entry was in the table, but with the wrong sw_if_index mapping (mac move) */
184 counter_base[L2LEARN_ERROR_MAC_MOVE] += 1;
186 if (result0->fields.static_mac)
189 * Don't overwrite a static mac
190 * TODO: Check violation policy. For now drop the packet
192 b0->error = node->errors[L2LEARN_ERROR_MAC_MOVE_VIOLATE];
193 *next0 = L2LEARN_NEXT_DROP;
199 * TODO: may want to rate limit mac moves
200 * TODO: check global/bridge domain/interface learn limits
202 BVT (clib_bihash_kv) kv;
204 result0->raw = 0; /* clear all fields */
205 result0->fields.sw_if_index = sw_if_index0;
206 result0->fields.timestamp = timestamp;
209 kv.value = result0->raw;
211 cached_key->raw = ~0; /* invalidate the cache */
213 BV (clib_bihash_add_del) (msm->mac_table, &kv, 1 /* is_add */ );
217 if (result0->fields.filter)
219 /* drop packet because lookup matched a filter mac entry */
221 if (*next0 != L2LEARN_NEXT_DROP)
223 /* if we're not already dropping the packet, do it now */
224 b0->error = node->errors[L2LEARN_ERROR_FILTER_DROP];
225 *next0 = L2LEARN_NEXT_DROP;
235 l2learn_node_fn (vlib_main_t * vm,
236 vlib_node_runtime_t * node, vlib_frame_t * frame)
238 u32 n_left_from, *from, *to_next;
239 l2learn_next_t next_index;
240 l2learn_main_t *msm = &l2learn_main;
241 vlib_node_t *n = vlib_get_node (vm, l2learn_node.index);
242 u32 node_counter_base_index = n->error_heap_index;
243 vlib_error_main_t *em = &vm->error_main;
244 l2fib_entry_key_t cached_key;
245 l2fib_entry_result_t cached_result;
246 u8 timestamp = (u8) (vlib_time_now (vm) / 60);
248 from = vlib_frame_vector_args (frame);
249 n_left_from = frame->n_vectors; /* number of packets to process */
250 next_index = node->cached_next_index;
252 /* Clear the one-entry cache in case mac table was updated */
254 cached_result.raw = ~0; /* warning be gone */
256 while (n_left_from > 0)
260 /* get space to enqueue frame to graph node "next_index" */
261 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
263 while (n_left_from >= 8 && n_left_to_next >= 4)
265 u32 bi0, bi1, bi2, bi3;
266 vlib_buffer_t *b0, *b1, *b2, *b3;
267 u32 next0, next1, next2, next3;
268 u32 sw_if_index0, sw_if_index1, sw_if_index2, sw_if_index3;
269 ethernet_header_t *h0, *h1, *h2, *h3;
270 l2fib_entry_key_t key0, key1, key2, key3;
271 l2fib_entry_result_t result0, result1, result2, result3;
272 u32 bucket0, bucket1, bucket2, bucket3;
274 /* Prefetch next iteration. */
276 vlib_buffer_t *p4, *p5, *p6, *p7;;
278 p4 = vlib_get_buffer (vm, from[4]);
279 p5 = vlib_get_buffer (vm, from[5]);
280 p6 = vlib_get_buffer (vm, from[6]);
281 p7 = vlib_get_buffer (vm, from[7]);
283 vlib_prefetch_buffer_header (p4, LOAD);
284 vlib_prefetch_buffer_header (p5, LOAD);
285 vlib_prefetch_buffer_header (p6, LOAD);
286 vlib_prefetch_buffer_header (p7, LOAD);
288 CLIB_PREFETCH (p4->data, CLIB_CACHE_LINE_BYTES, STORE);
289 CLIB_PREFETCH (p5->data, CLIB_CACHE_LINE_BYTES, STORE);
290 CLIB_PREFETCH (p6->data, CLIB_CACHE_LINE_BYTES, STORE);
291 CLIB_PREFETCH (p7->data, CLIB_CACHE_LINE_BYTES, STORE);
294 /* speculatively enqueue b0 and b1 to the current next frame */
295 /* bi is "buffer index", b is pointer to the buffer */
296 to_next[0] = bi0 = from[0];
297 to_next[1] = bi1 = from[1];
298 to_next[2] = bi2 = from[2];
299 to_next[3] = bi3 = from[3];
305 b0 = vlib_get_buffer (vm, bi0);
306 b1 = vlib_get_buffer (vm, bi1);
307 b2 = vlib_get_buffer (vm, bi2);
308 b3 = vlib_get_buffer (vm, bi3);
310 /* RX interface handles */
311 sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
312 sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
313 sw_if_index2 = vnet_buffer (b2)->sw_if_index[VLIB_RX];
314 sw_if_index3 = vnet_buffer (b3)->sw_if_index[VLIB_RX];
316 /* Process 4 x pkts */
318 h0 = vlib_buffer_get_current (b0);
319 h1 = vlib_buffer_get_current (b1);
320 h2 = vlib_buffer_get_current (b2);
321 h3 = vlib_buffer_get_current (b3);
323 if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)))
325 if (b0->flags & VLIB_BUFFER_IS_TRACED)
328 vlib_add_trace (vm, node, b0, sizeof (*t));
329 t->sw_if_index = sw_if_index0;
330 t->bd_index = vnet_buffer (b0)->l2.bd_index;
331 clib_memcpy (t->src, h0->src_address, 6);
332 clib_memcpy (t->dst, h0->dst_address, 6);
334 if (b1->flags & VLIB_BUFFER_IS_TRACED)
337 vlib_add_trace (vm, node, b1, sizeof (*t));
338 t->sw_if_index = sw_if_index1;
339 t->bd_index = vnet_buffer (b1)->l2.bd_index;
340 clib_memcpy (t->src, h1->src_address, 6);
341 clib_memcpy (t->dst, h1->dst_address, 6);
343 if (b2->flags & VLIB_BUFFER_IS_TRACED)
346 vlib_add_trace (vm, node, b2, sizeof (*t));
347 t->sw_if_index = sw_if_index2;
348 t->bd_index = vnet_buffer (b2)->l2.bd_index;
349 clib_memcpy (t->src, h2->src_address, 6);
350 clib_memcpy (t->dst, h2->dst_address, 6);
352 if (b3->flags & VLIB_BUFFER_IS_TRACED)
355 vlib_add_trace (vm, node, b3, sizeof (*t));
356 t->sw_if_index = sw_if_index3;
357 t->bd_index = vnet_buffer (b3)->l2.bd_index;
358 clib_memcpy (t->src, h3->src_address, 6);
359 clib_memcpy (t->dst, h3->dst_address, 6);
364 vlib_node_increment_counter (vm, l2learn_node.index,
365 L2LEARN_ERROR_L2LEARN, 4);
367 l2fib_lookup_4 (msm->mac_table, &cached_key, &cached_result,
372 vnet_buffer (b0)->l2.bd_index,
373 vnet_buffer (b1)->l2.bd_index,
374 vnet_buffer (b2)->l2.bd_index,
375 vnet_buffer (b3)->l2.bd_index,
376 &key0, &key1, &key2, &key3,
377 &bucket0, &bucket1, &bucket2, &bucket3,
378 &result0, &result1, &result2, &result3);
380 l2learn_process (node, msm, &em->counters[node_counter_base_index],
381 b0, sw_if_index0, &key0, &cached_key,
382 &bucket0, &result0, &next0, timestamp);
384 l2learn_process (node, msm, &em->counters[node_counter_base_index],
385 b1, sw_if_index1, &key1, &cached_key,
386 &bucket1, &result1, &next1, timestamp);
388 l2learn_process (node, msm, &em->counters[node_counter_base_index],
389 b2, sw_if_index2, &key2, &cached_key,
390 &bucket2, &result2, &next2, timestamp);
392 l2learn_process (node, msm, &em->counters[node_counter_base_index],
393 b3, sw_if_index3, &key3, &cached_key,
394 &bucket3, &result3, &next3, timestamp);
396 /* verify speculative enqueues, maybe switch current next frame */
397 /* if next0==next1==next_index then nothing special needs to be done */
398 vlib_validate_buffer_enqueue_x4 (vm, node, next_index,
399 to_next, n_left_to_next,
401 next0, next1, next2, next3);
404 while (n_left_from > 0 && n_left_to_next > 0)
410 ethernet_header_t *h0;
411 l2fib_entry_key_t key0;
412 l2fib_entry_result_t result0;
415 /* speculatively enqueue b0 to the current next frame */
423 b0 = vlib_get_buffer (vm, bi0);
425 sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
427 h0 = vlib_buffer_get_current (b0);
429 if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
430 && (b0->flags & VLIB_BUFFER_IS_TRACED)))
432 l2learn_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
433 t->sw_if_index = sw_if_index0;
434 t->bd_index = vnet_buffer (b0)->l2.bd_index;
435 clib_memcpy (t->src, h0->src_address, 6);
436 clib_memcpy (t->dst, h0->dst_address, 6);
440 vlib_node_increment_counter (vm, l2learn_node.index,
441 L2LEARN_ERROR_L2LEARN, 1);
444 l2fib_lookup_1 (msm->mac_table, &cached_key, &cached_result,
445 h0->src_address, vnet_buffer (b0)->l2.bd_index,
446 &key0, &bucket0, &result0);
448 l2learn_process (node, msm, &em->counters[node_counter_base_index],
449 b0, sw_if_index0, &key0, &cached_key,
450 &bucket0, &result0, &next0, timestamp);
452 /* verify speculative enqueue, maybe switch current next frame */
453 vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
454 to_next, n_left_to_next,
458 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
461 return frame->n_vectors;
466 VLIB_REGISTER_NODE (l2learn_node,static) = {
467 .function = l2learn_node_fn,
469 .vector_size = sizeof (u32),
470 .format_trace = format_l2learn_trace,
471 .type = VLIB_NODE_TYPE_INTERNAL,
473 .n_errors = ARRAY_LEN(l2learn_error_strings),
474 .error_strings = l2learn_error_strings,
476 .n_next_nodes = L2LEARN_N_NEXT,
478 /* edit / add dispositions here */
480 [L2LEARN_NEXT_DROP] = "error-drop",
481 [L2LEARN_NEXT_L2FWD] = "l2-fwd",
486 VLIB_NODE_FUNCTION_MULTIARCH (l2learn_node, l2learn_node_fn)
487 clib_error_t *l2learn_init (vlib_main_t * vm)
489 l2learn_main_t *mp = &l2learn_main;
492 mp->vnet_main = vnet_get_main ();
494 /* Initialize the feature next-node indexes */
495 feat_bitmap_init_next_nodes (vm,
498 l2input_get_feat_names (),
499 mp->feat_next_node_index);
501 /* init the hash table ptr */
502 mp->mac_table = get_mac_table ();
505 * Set the default number of dynamically learned macs to the number
508 mp->global_learn_limit = L2FIB_NUM_BUCKETS * 16;
513 VLIB_INIT_FUNCTION (l2learn_init);
517 * Set subinterface learn enable/disable.
519 * set interface l2 learn <interface> [disable]
521 static clib_error_t *
522 int_learn (vlib_main_t * vm,
523 unformat_input_t * input, vlib_cli_command_t * cmd)
525 vnet_main_t *vnm = vnet_get_main ();
526 clib_error_t *error = 0;
530 if (!unformat_user (input, unformat_vnet_sw_interface, vnm, &sw_if_index))
532 error = clib_error_return (0, "unknown interface `%U'",
533 format_unformat_error, input);
538 if (unformat (input, "disable"))
543 /* set the interface flag */
544 l2input_intf_bitmap_enable (sw_if_index, L2INPUT_FEAT_LEARN, enable);
551 * Layer 2 learning can be enabled and disabled on each
552 * interface and on each bridge-domain. Use this command to
553 * manage interfaces. It is enabled by default.
556 * Example of how to enable learning:
557 * @cliexcmd{set interface l2 learn GigabitEthernet0/8/0}
558 * Example of how to disable learning:
559 * @cliexcmd{set interface l2 learn GigabitEthernet0/8/0 disable}
562 VLIB_CLI_COMMAND (int_learn_cli, static) = {
563 .path = "set interface l2 learn",
564 .short_help = "set interface l2 learn <interface> [disable]",
565 .function = int_learn,
570 static clib_error_t *
571 l2learn_config (vlib_main_t * vm, unformat_input_t * input)
573 l2learn_main_t *mp = &l2learn_main;
575 while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
577 if (unformat (input, "limit %d", &mp->global_learn_limit))
581 return clib_error_return (0, "unknown input `%U'",
582 format_unformat_error, input);
588 VLIB_CONFIG_FUNCTION (l2learn_config, "l2learn");
592 * fd.io coding-style-patch-verification: ON
595 * eval: (c-set-style "gnu")