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)
119 /* Set up the default next node (typically L2FWD) */
120 *next0 = vnet_l2_feature_next (b0, msm->feat_next_node_index,
123 /* Check mac table lookup result */
124 if (PREDICT_TRUE (result0->fields.sw_if_index == sw_if_index0))
127 * The entry was in the table, and the sw_if_index matched, the normal case
129 counter_base[L2LEARN_ERROR_HIT] += 1;
130 int update = !result0->fields.static_mac &&
131 (result0->fields.timestamp != timestamp ||
132 result0->fields.sn.as_u16 != vnet_buffer (b0)->l2.l2fib_sn);
134 if (PREDICT_TRUE (!update))
137 else if (result0->raw == ~0)
139 /* The entry was not in table, so add it */
140 counter_base[L2LEARN_ERROR_MISS] += 1;
142 if (msm->global_learn_count == msm->global_learn_limit)
145 * Global limit reached. Do not learn the mac but forward the packet.
146 * In the future, limits could also be per-interface or bridge-domain.
148 counter_base[L2LEARN_ERROR_LIMIT] += 1;
152 /* It is ok to learn */
153 msm->global_learn_count++;
154 result0->raw = 0; /* clear all fields */
155 result0->fields.sw_if_index = sw_if_index0;
156 cached_key->raw = ~0; /* invalidate the cache */
160 /* The entry was in the table, but with the wrong sw_if_index mapping (mac move) */
161 if (result0->fields.filter)
163 ASSERT (result0->fields.sw_if_index == ~0);
164 /* drop packet because lookup matched a filter mac entry */
165 b0->error = node->errors[L2LEARN_ERROR_FILTER_DROP];
166 *next0 = L2LEARN_NEXT_DROP;
170 counter_base[L2LEARN_ERROR_MAC_MOVE] += 1;
172 if (result0->fields.static_mac)
175 * Don't overwrite a static mac
176 * TODO: Check violation policy. For now drop the packet
178 b0->error = node->errors[L2LEARN_ERROR_MAC_MOVE_VIOLATE];
179 *next0 = L2LEARN_NEXT_DROP;
184 * TODO: may want to rate limit mac moves
185 * TODO: check global/bridge domain/interface learn limits
187 result0->fields.sw_if_index = sw_if_index0;
190 /* Update the entry */
191 result0->fields.timestamp = timestamp;
192 result0->fields.sn.as_u16 = vnet_buffer (b0)->l2.l2fib_sn;
194 BVT (clib_bihash_kv) kv;
196 kv.value = result0->raw;
197 BV (clib_bihash_add_del) (msm->mac_table, &kv, 1 /* is_add */ );
201 static_always_inline uword
202 l2learn_node_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
203 vlib_frame_t * frame, int do_trace)
205 u32 n_left_from, *from, *to_next;
206 l2learn_next_t next_index;
207 l2learn_main_t *msm = &l2learn_main;
208 vlib_node_t *n = vlib_get_node (vm, l2learn_node.index);
209 u32 node_counter_base_index = n->error_heap_index;
210 vlib_error_main_t *em = &vm->error_main;
211 l2fib_entry_key_t cached_key;
212 l2fib_entry_result_t cached_result;
213 u8 timestamp = (u8) (vlib_time_now (vm) / 60);
215 from = vlib_frame_vector_args (frame);
216 n_left_from = frame->n_vectors; /* number of packets to process */
217 next_index = node->cached_next_index;
219 /* Clear the one-entry cache in case mac table was updated */
221 cached_result.raw = ~0; /* warning be gone */
223 while (n_left_from > 0)
227 /* get space to enqueue frame to graph node "next_index" */
228 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
230 while (n_left_from >= 8 && n_left_to_next >= 4)
232 u32 bi0, bi1, bi2, bi3;
233 vlib_buffer_t *b0, *b1, *b2, *b3;
234 u32 next0, next1, next2, next3;
235 u32 sw_if_index0, sw_if_index1, sw_if_index2, sw_if_index3;
236 ethernet_header_t *h0, *h1, *h2, *h3;
237 l2fib_entry_key_t key0, key1, key2, key3;
238 l2fib_entry_result_t result0, result1, result2, result3;
239 u32 bucket0, bucket1, bucket2, bucket3;
241 /* Prefetch next iteration. */
243 vlib_buffer_t *p4, *p5, *p6, *p7;;
245 p4 = vlib_get_buffer (vm, from[4]);
246 p5 = vlib_get_buffer (vm, from[5]);
247 p6 = vlib_get_buffer (vm, from[6]);
248 p7 = vlib_get_buffer (vm, from[7]);
250 vlib_prefetch_buffer_header (p4, LOAD);
251 vlib_prefetch_buffer_header (p5, LOAD);
252 vlib_prefetch_buffer_header (p6, LOAD);
253 vlib_prefetch_buffer_header (p7, LOAD);
255 CLIB_PREFETCH (p4->data, CLIB_CACHE_LINE_BYTES, STORE);
256 CLIB_PREFETCH (p5->data, CLIB_CACHE_LINE_BYTES, STORE);
257 CLIB_PREFETCH (p6->data, CLIB_CACHE_LINE_BYTES, STORE);
258 CLIB_PREFETCH (p7->data, CLIB_CACHE_LINE_BYTES, STORE);
261 /* speculatively enqueue b0 and b1 to the current next frame */
262 /* bi is "buffer index", b is pointer to the buffer */
263 to_next[0] = bi0 = from[0];
264 to_next[1] = bi1 = from[1];
265 to_next[2] = bi2 = from[2];
266 to_next[3] = bi3 = from[3];
272 b0 = vlib_get_buffer (vm, bi0);
273 b1 = vlib_get_buffer (vm, bi1);
274 b2 = vlib_get_buffer (vm, bi2);
275 b3 = vlib_get_buffer (vm, bi3);
277 /* RX interface handles */
278 sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
279 sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
280 sw_if_index2 = vnet_buffer (b2)->sw_if_index[VLIB_RX];
281 sw_if_index3 = vnet_buffer (b3)->sw_if_index[VLIB_RX];
283 /* Process 4 x pkts */
285 h0 = vlib_buffer_get_current (b0);
286 h1 = vlib_buffer_get_current (b1);
287 h2 = vlib_buffer_get_current (b2);
288 h3 = vlib_buffer_get_current (b3);
292 if (b0->flags & VLIB_BUFFER_IS_TRACED)
295 vlib_add_trace (vm, node, b0, sizeof (*t));
296 t->sw_if_index = sw_if_index0;
297 t->bd_index = vnet_buffer (b0)->l2.bd_index;
298 clib_memcpy (t->src, h0->src_address, 6);
299 clib_memcpy (t->dst, h0->dst_address, 6);
301 if (b1->flags & VLIB_BUFFER_IS_TRACED)
304 vlib_add_trace (vm, node, b1, sizeof (*t));
305 t->sw_if_index = sw_if_index1;
306 t->bd_index = vnet_buffer (b1)->l2.bd_index;
307 clib_memcpy (t->src, h1->src_address, 6);
308 clib_memcpy (t->dst, h1->dst_address, 6);
310 if (b2->flags & VLIB_BUFFER_IS_TRACED)
313 vlib_add_trace (vm, node, b2, sizeof (*t));
314 t->sw_if_index = sw_if_index2;
315 t->bd_index = vnet_buffer (b2)->l2.bd_index;
316 clib_memcpy (t->src, h2->src_address, 6);
317 clib_memcpy (t->dst, h2->dst_address, 6);
319 if (b3->flags & VLIB_BUFFER_IS_TRACED)
322 vlib_add_trace (vm, node, b3, sizeof (*t));
323 t->sw_if_index = sw_if_index3;
324 t->bd_index = vnet_buffer (b3)->l2.bd_index;
325 clib_memcpy (t->src, h3->src_address, 6);
326 clib_memcpy (t->dst, h3->dst_address, 6);
331 vlib_node_increment_counter (vm, l2learn_node.index,
332 L2LEARN_ERROR_L2LEARN, 4);
334 l2fib_lookup_4 (msm->mac_table, &cached_key, &cached_result,
339 vnet_buffer (b0)->l2.bd_index,
340 vnet_buffer (b1)->l2.bd_index,
341 vnet_buffer (b2)->l2.bd_index,
342 vnet_buffer (b3)->l2.bd_index,
343 &key0, &key1, &key2, &key3,
344 &bucket0, &bucket1, &bucket2, &bucket3,
345 &result0, &result1, &result2, &result3);
347 l2learn_process (node, msm, &em->counters[node_counter_base_index],
348 b0, sw_if_index0, &key0, &cached_key,
349 &bucket0, &result0, &next0, timestamp);
351 l2learn_process (node, msm, &em->counters[node_counter_base_index],
352 b1, sw_if_index1, &key1, &cached_key,
353 &bucket1, &result1, &next1, timestamp);
355 l2learn_process (node, msm, &em->counters[node_counter_base_index],
356 b2, sw_if_index2, &key2, &cached_key,
357 &bucket2, &result2, &next2, timestamp);
359 l2learn_process (node, msm, &em->counters[node_counter_base_index],
360 b3, sw_if_index3, &key3, &cached_key,
361 &bucket3, &result3, &next3, timestamp);
363 /* verify speculative enqueues, maybe switch current next frame */
364 /* if next0==next1==next_index then nothing special needs to be done */
365 vlib_validate_buffer_enqueue_x4 (vm, node, next_index,
366 to_next, n_left_to_next,
368 next0, next1, next2, next3);
371 while (n_left_from > 0 && n_left_to_next > 0)
377 ethernet_header_t *h0;
378 l2fib_entry_key_t key0;
379 l2fib_entry_result_t result0;
382 /* speculatively enqueue b0 to the current next frame */
390 b0 = vlib_get_buffer (vm, bi0);
392 sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
394 h0 = vlib_buffer_get_current (b0);
396 if (do_trace && PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
398 l2learn_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
399 t->sw_if_index = sw_if_index0;
400 t->bd_index = vnet_buffer (b0)->l2.bd_index;
401 clib_memcpy (t->src, h0->src_address, 6);
402 clib_memcpy (t->dst, h0->dst_address, 6);
406 vlib_node_increment_counter (vm, l2learn_node.index,
407 L2LEARN_ERROR_L2LEARN, 1);
410 l2fib_lookup_1 (msm->mac_table, &cached_key, &cached_result,
411 h0->src_address, vnet_buffer (b0)->l2.bd_index,
412 &key0, &bucket0, &result0);
414 l2learn_process (node, msm, &em->counters[node_counter_base_index],
415 b0, sw_if_index0, &key0, &cached_key,
416 &bucket0, &result0, &next0, timestamp);
418 /* verify speculative enqueue, maybe switch current next frame */
419 vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
420 to_next, n_left_to_next,
424 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
427 return frame->n_vectors;
431 l2learn_node_fn (vlib_main_t * vm,
432 vlib_node_runtime_t * node, vlib_frame_t * frame)
434 if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)))
435 return l2learn_node_inline (vm, node, frame, 1 /* do_trace */ );
436 return l2learn_node_inline (vm, node, frame, 0 /* do_trace */ );
440 VLIB_REGISTER_NODE (l2learn_node,static) = {
441 .function = l2learn_node_fn,
443 .vector_size = sizeof (u32),
444 .format_trace = format_l2learn_trace,
445 .type = VLIB_NODE_TYPE_INTERNAL,
447 .n_errors = ARRAY_LEN(l2learn_error_strings),
448 .error_strings = l2learn_error_strings,
450 .n_next_nodes = L2LEARN_N_NEXT,
452 /* edit / add dispositions here */
454 [L2LEARN_NEXT_DROP] = "error-drop",
455 [L2LEARN_NEXT_L2FWD] = "l2-fwd",
460 VLIB_NODE_FUNCTION_MULTIARCH (l2learn_node, l2learn_node_fn)
461 clib_error_t *l2learn_init (vlib_main_t * vm)
463 l2learn_main_t *mp = &l2learn_main;
466 mp->vnet_main = vnet_get_main ();
468 /* Initialize the feature next-node indexes */
469 feat_bitmap_init_next_nodes (vm,
472 l2input_get_feat_names (),
473 mp->feat_next_node_index);
475 /* init the hash table ptr */
476 mp->mac_table = get_mac_table ();
479 * Set the default number of dynamically learned macs to the number
482 mp->global_learn_limit = L2FIB_NUM_BUCKETS * 16;
487 VLIB_INIT_FUNCTION (l2learn_init);
491 * Set subinterface learn enable/disable.
493 * set interface l2 learn <interface> [disable]
495 static clib_error_t *
496 int_learn (vlib_main_t * vm,
497 unformat_input_t * input, vlib_cli_command_t * cmd)
499 vnet_main_t *vnm = vnet_get_main ();
500 clib_error_t *error = 0;
504 if (!unformat_user (input, unformat_vnet_sw_interface, vnm, &sw_if_index))
506 error = clib_error_return (0, "unknown interface `%U'",
507 format_unformat_error, input);
512 if (unformat (input, "disable"))
517 /* set the interface flag */
518 l2input_intf_bitmap_enable (sw_if_index, L2INPUT_FEAT_LEARN, enable);
525 * Layer 2 learning can be enabled and disabled on each
526 * interface and on each bridge-domain. Use this command to
527 * manage interfaces. It is enabled by default.
530 * Example of how to enable learning:
531 * @cliexcmd{set interface l2 learn GigabitEthernet0/8/0}
532 * Example of how to disable learning:
533 * @cliexcmd{set interface l2 learn GigabitEthernet0/8/0 disable}
536 VLIB_CLI_COMMAND (int_learn_cli, static) = {
537 .path = "set interface l2 learn",
538 .short_help = "set interface l2 learn <interface> [disable]",
539 .function = int_learn,
544 static clib_error_t *
545 l2learn_config (vlib_main_t * vm, unformat_input_t * input)
547 l2learn_main_t *mp = &l2learn_main;
549 while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
551 if (unformat (input, "limit %d", &mp->global_learn_limit))
555 return clib_error_return (0, "unknown input `%U'",
556 format_unformat_error, input);
562 VLIB_CONFIG_FUNCTION (l2learn_config, "l2learn");
566 * fd.io coding-style-patch-verification: ON
569 * eval: (c-set-style "gnu")