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>
32 #ifndef CLIB_MARCH_VARIANT
33 l2learn_main_t l2learn_main;
38 * @brief Ethernet Bridge Learning.
40 * Populate the mac table with entries mapping the packet's source mac + bridge
41 * domain ID to the input sw_if_index.
43 * Note that learning and forwarding are separate graph nodes. This means that
44 * for a set of packets, all learning is performed first, then all nodes are
45 * forwarded. The forwarding is done based on the end-state of the mac table,
46 * instead of the state after each packet. Thus the forwarding results could
47 * differ in certain cases (mac move tests), but this not expected to cause
48 * problems in real-world networks. It is much simpler to separate learning
49 * and forwarding into separate nodes.
62 /* packet trace format function */
64 format_l2learn_trace (u8 * s, va_list * args)
66 CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
67 CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
68 l2learn_trace_t *t = va_arg (*args, l2learn_trace_t *);
70 s = format (s, "l2-learn: sw_if_index %d dst %U src %U bd_index %d",
72 format_ethernet_address, t->dst,
73 format_ethernet_address, t->src, t->bd_index);
77 static vlib_node_registration_t l2learn_node;
79 #define foreach_l2learn_error \
80 _(L2LEARN, "L2 learn packets") \
81 _(MISS, "L2 learn misses") \
82 _(MAC_MOVE, "L2 mac moves") \
83 _(MAC_MOVE_VIOLATE, "L2 mac move violations") \
84 _(LIMIT, "L2 not learned due to limit") \
85 _(HIT_UPDATE, "L2 learn hit updates") \
86 _(FILTER_DROP, "L2 filter mac drops")
90 #define _(sym,str) L2LEARN_ERROR_##sym,
96 static char *l2learn_error_strings[] = {
97 #define _(sym,string) string,
110 /** Perform learning on one packet based on the mac table lookup result. */
112 static_always_inline void
113 l2learn_process (vlib_node_runtime_t * node,
114 l2learn_main_t * msm,
118 l2fib_entry_key_t * key0,
119 l2fib_entry_key_t * cached_key,
121 l2fib_entry_result_t * result0, u32 * next0, u8 timestamp)
123 /* Set up the default next node (typically L2FWD) */
124 *next0 = vnet_l2_feature_next (b0, msm->feat_next_node_index,
127 /* Check mac table lookup result */
128 if (PREDICT_TRUE (result0->fields.sw_if_index == sw_if_index0))
130 /* Entry in L2FIB with matching sw_if_index matched - normal fast path */
131 u32 dtime = timestamp - result0->fields.timestamp;
132 u32 dsn = result0->fields.sn.as_u16 - vnet_buffer (b0)->l2.l2fib_sn;
133 u32 check = (dtime && vnet_buffer (b0)->l2.bd_age) || dsn;
135 if (PREDICT_TRUE (check == 0))
136 return; /* MAC entry up to date */
137 if (l2fib_entry_result_is_set_AGE_NOT (result0))
138 return; /* Static MAC always age_not */
139 if (msm->global_learn_count > msm->global_learn_limit)
140 return; /* Above learn limit - do not update */
142 /* Limit updates per l2-learn node call to avoid prolonged update burst
143 * as dtime advance over 1 minute mark, unless more than 1 min behind
145 if ((*count > 2) && (dtime == 1) && (dsn == 0))
148 counter_base[L2LEARN_ERROR_HIT_UPDATE] += 1;
151 else if (result0->raw == ~0)
153 /* Entry not in L2FIB - add it */
154 counter_base[L2LEARN_ERROR_MISS] += 1;
156 if (msm->global_learn_count >= msm->global_learn_limit)
159 * Global limit reached. Do not learn the mac but forward the packet.
160 * In the future, limits could also be per-interface or bridge-domain.
162 counter_base[L2LEARN_ERROR_LIMIT] += 1;
166 /* Do not learn if mac is 0 */
167 l2fib_entry_key_t key = *key0;
168 key.fields.bd_index = 0;
172 /* It is ok to learn */
173 msm->global_learn_count++;
174 result0->raw = 0; /* clear all fields */
175 result0->fields.sw_if_index = sw_if_index0;
176 if (msm->client_pid != 0)
177 l2fib_entry_result_set_LRN_EVT (result0);
179 l2fib_entry_result_clear_LRN_EVT (result0);
183 /* Entry in L2FIB with different sw_if_index - mac move or filter */
184 if (l2fib_entry_result_is_set_FILTER (result0))
186 ASSERT (result0->fields.sw_if_index == ~0);
187 /* drop packet because lookup matched a filter mac entry */
188 b0->error = node->errors[L2LEARN_ERROR_FILTER_DROP];
189 *next0 = L2LEARN_NEXT_DROP;
193 if (l2fib_entry_result_is_set_STATIC (result0))
196 * Don't overwrite a static mac
197 * TODO: Check violation policy. For now drop the packet
199 b0->error = node->errors[L2LEARN_ERROR_MAC_MOVE_VIOLATE];
200 *next0 = L2LEARN_NEXT_DROP;
205 * TODO: may want to rate limit mac moves
206 * TODO: check global/bridge domain/interface learn limits
208 result0->fields.sw_if_index = sw_if_index0;
209 if (l2fib_entry_result_is_set_AGE_NOT (result0))
211 /* The mac was provisioned */
212 msm->global_learn_count++;
213 l2fib_entry_result_clear_AGE_NOT (result0);
215 if (msm->client_pid != 0)
216 l2fib_entry_result_set_bits (result0,
217 (L2FIB_ENTRY_RESULT_FLAG_LRN_EVT |
218 L2FIB_ENTRY_RESULT_FLAG_LRN_MOV));
220 l2fib_entry_result_clear_bits (result0,
221 (L2FIB_ENTRY_RESULT_FLAG_LRN_EVT |
222 L2FIB_ENTRY_RESULT_FLAG_LRN_MOV));
223 counter_base[L2LEARN_ERROR_MAC_MOVE] += 1;
226 /* Update the entry */
227 result0->fields.timestamp = timestamp;
228 result0->fields.sn.as_u16 = vnet_buffer (b0)->l2.l2fib_sn;
230 BVT (clib_bihash_kv) kv;
232 kv.value = result0->raw;
233 BV (clib_bihash_add_del) (msm->mac_table, &kv, 1 /* is_add */ );
235 /* Invalidate the cache */
236 cached_key->raw = ~0;
240 static_always_inline uword
241 l2learn_node_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
242 vlib_frame_t * frame, int do_trace)
244 u32 n_left_from, *from, *to_next;
245 l2learn_next_t next_index;
246 l2learn_main_t *msm = &l2learn_main;
247 vlib_node_t *n = vlib_get_node (vm, l2learn_node.index);
248 u32 node_counter_base_index = n->error_heap_index;
249 vlib_error_main_t *em = &vm->error_main;
250 l2fib_entry_key_t cached_key;
251 l2fib_entry_result_t cached_result;
252 u8 timestamp = (u8) (vlib_time_now (vm) / 60);
255 from = vlib_frame_vector_args (frame);
256 n_left_from = frame->n_vectors; /* number of packets to process */
257 next_index = node->cached_next_index;
259 /* Clear the one-entry cache in case mac table was updated */
261 cached_result.raw = ~0; /* warning be gone */
263 while (n_left_from > 0)
267 /* get space to enqueue frame to graph node "next_index" */
268 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
270 while (n_left_from >= 8 && n_left_to_next >= 4)
272 u32 bi0, bi1, bi2, bi3;
273 vlib_buffer_t *b0, *b1, *b2, *b3;
274 u32 next0, next1, next2, next3;
275 u32 sw_if_index0, sw_if_index1, sw_if_index2, sw_if_index3;
276 const ethernet_header_t *h0, *h1, *h2, *h3;
277 l2fib_entry_key_t key0, key1, key2, key3;
278 l2fib_entry_result_t result0, result1, result2, result3;
279 u32 bucket0, bucket1, bucket2, bucket3;
281 /* Prefetch next iteration. */
283 vlib_buffer_t *p4, *p5, *p6, *p7;;
285 p4 = vlib_get_buffer (vm, from[4]);
286 p5 = vlib_get_buffer (vm, from[5]);
287 p6 = vlib_get_buffer (vm, from[6]);
288 p7 = vlib_get_buffer (vm, from[7]);
290 /* buffer header is read and written, so use LOAD
292 vlib_prefetch_buffer_header (p4, LOAD);
293 vlib_prefetch_buffer_header (p5, LOAD);
294 vlib_prefetch_buffer_header (p6, LOAD);
295 vlib_prefetch_buffer_header (p7, LOAD);
297 CLIB_PREFETCH (p4->data, CLIB_CACHE_LINE_BYTES, LOAD);
298 CLIB_PREFETCH (p5->data, CLIB_CACHE_LINE_BYTES, LOAD);
299 CLIB_PREFETCH (p6->data, CLIB_CACHE_LINE_BYTES, LOAD);
300 CLIB_PREFETCH (p7->data, CLIB_CACHE_LINE_BYTES, LOAD);
303 /* speculatively enqueue b0 and b1 to the current next frame */
304 /* bi is "buffer index", b is pointer to the buffer */
305 to_next[0] = bi0 = from[0];
306 to_next[1] = bi1 = from[1];
307 to_next[2] = bi2 = from[2];
308 to_next[3] = bi3 = from[3];
314 b0 = vlib_get_buffer (vm, bi0);
315 b1 = vlib_get_buffer (vm, bi1);
316 b2 = vlib_get_buffer (vm, bi2);
317 b3 = vlib_get_buffer (vm, bi3);
319 /* RX interface handles */
320 sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
321 sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
322 sw_if_index2 = vnet_buffer (b2)->sw_if_index[VLIB_RX];
323 sw_if_index3 = vnet_buffer (b3)->sw_if_index[VLIB_RX];
325 /* Process 4 x pkts */
327 h0 = vlib_buffer_get_current (b0);
328 h1 = vlib_buffer_get_current (b1);
329 h2 = vlib_buffer_get_current (b2);
330 h3 = vlib_buffer_get_current (b3);
334 if (b0->flags & VLIB_BUFFER_IS_TRACED)
337 vlib_add_trace (vm, node, b0, sizeof (*t));
338 t->sw_if_index = sw_if_index0;
339 t->bd_index = vnet_buffer (b0)->l2.bd_index;
340 clib_memcpy (t->src, h0->src_address, 6);
341 clib_memcpy (t->dst, h0->dst_address, 6);
343 if (b1->flags & VLIB_BUFFER_IS_TRACED)
346 vlib_add_trace (vm, node, b1, sizeof (*t));
347 t->sw_if_index = sw_if_index1;
348 t->bd_index = vnet_buffer (b1)->l2.bd_index;
349 clib_memcpy (t->src, h1->src_address, 6);
350 clib_memcpy (t->dst, h1->dst_address, 6);
352 if (b2->flags & VLIB_BUFFER_IS_TRACED)
355 vlib_add_trace (vm, node, b2, sizeof (*t));
356 t->sw_if_index = sw_if_index2;
357 t->bd_index = vnet_buffer (b2)->l2.bd_index;
358 clib_memcpy (t->src, h2->src_address, 6);
359 clib_memcpy (t->dst, h2->dst_address, 6);
361 if (b3->flags & VLIB_BUFFER_IS_TRACED)
364 vlib_add_trace (vm, node, b3, sizeof (*t));
365 t->sw_if_index = sw_if_index3;
366 t->bd_index = vnet_buffer (b3)->l2.bd_index;
367 clib_memcpy (t->src, h3->src_address, 6);
368 clib_memcpy (t->dst, h3->dst_address, 6);
373 vlib_node_increment_counter (vm, l2learn_node.index,
374 L2LEARN_ERROR_L2LEARN, 4);
376 l2fib_lookup_4 (msm->mac_table, &cached_key, &cached_result,
381 vnet_buffer (b0)->l2.bd_index,
382 vnet_buffer (b1)->l2.bd_index,
383 vnet_buffer (b2)->l2.bd_index,
384 vnet_buffer (b3)->l2.bd_index,
385 &key0, &key1, &key2, &key3,
386 &bucket0, &bucket1, &bucket2, &bucket3,
387 &result0, &result1, &result2, &result3);
389 l2learn_process (node, msm, &em->counters[node_counter_base_index],
390 b0, sw_if_index0, &key0, &cached_key,
391 &count, &result0, &next0, timestamp);
393 l2learn_process (node, msm, &em->counters[node_counter_base_index],
394 b1, sw_if_index1, &key1, &cached_key,
395 &count, &result1, &next1, timestamp);
397 l2learn_process (node, msm, &em->counters[node_counter_base_index],
398 b2, sw_if_index2, &key2, &cached_key,
399 &count, &result2, &next2, timestamp);
401 l2learn_process (node, msm, &em->counters[node_counter_base_index],
402 b3, sw_if_index3, &key3, &cached_key,
403 &count, &result3, &next3, timestamp);
405 /* verify speculative enqueues, maybe switch current next frame */
406 /* if next0==next1==next_index then nothing special needs to be done */
407 vlib_validate_buffer_enqueue_x4 (vm, node, next_index,
408 to_next, n_left_to_next,
410 next0, next1, next2, next3);
413 while (n_left_from > 0 && n_left_to_next > 0)
419 ethernet_header_t *h0;
420 l2fib_entry_key_t key0;
421 l2fib_entry_result_t result0;
424 /* speculatively enqueue b0 to the current next frame */
432 b0 = vlib_get_buffer (vm, bi0);
434 sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
436 h0 = vlib_buffer_get_current (b0);
438 if (do_trace && PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
440 l2learn_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
441 t->sw_if_index = sw_if_index0;
442 t->bd_index = vnet_buffer (b0)->l2.bd_index;
443 clib_memcpy (t->src, h0->src_address, 6);
444 clib_memcpy (t->dst, h0->dst_address, 6);
448 vlib_node_increment_counter (vm, l2learn_node.index,
449 L2LEARN_ERROR_L2LEARN, 1);
452 l2fib_lookup_1 (msm->mac_table, &cached_key, &cached_result,
453 h0->src_address, vnet_buffer (b0)->l2.bd_index,
454 &key0, &bucket0, &result0);
456 l2learn_process (node, msm, &em->counters[node_counter_base_index],
457 b0, sw_if_index0, &key0, &cached_key,
458 &count, &result0, &next0, timestamp);
460 /* verify speculative enqueue, maybe switch current next frame */
461 vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
462 to_next, n_left_to_next,
466 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
469 return frame->n_vectors;
472 VLIB_NODE_FN (l2learn_node) (vlib_main_t * vm,
473 vlib_node_runtime_t * node, vlib_frame_t * frame)
475 if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)))
476 return l2learn_node_inline (vm, node, frame, 1 /* do_trace */ );
477 return l2learn_node_inline (vm, node, frame, 0 /* do_trace */ );
481 VLIB_REGISTER_NODE (l2learn_node,static) = {
483 .vector_size = sizeof (u32),
484 .format_trace = format_l2learn_trace,
485 .type = VLIB_NODE_TYPE_INTERNAL,
487 .n_errors = ARRAY_LEN(l2learn_error_strings),
488 .error_strings = l2learn_error_strings,
490 .n_next_nodes = L2LEARN_N_NEXT,
492 /* edit / add dispositions here */
494 [L2LEARN_NEXT_DROP] = "error-drop",
495 [L2LEARN_NEXT_L2FWD] = "l2-fwd",
500 #ifndef CLIB_MARCH_VARIANT
502 l2learn_init (vlib_main_t * vm)
504 l2learn_main_t *mp = &l2learn_main;
507 mp->vnet_main = vnet_get_main ();
509 /* Initialize the feature next-node indexes */
510 feat_bitmap_init_next_nodes (vm,
513 l2input_get_feat_names (),
514 mp->feat_next_node_index);
516 /* init the hash table ptr */
517 mp->mac_table = get_mac_table ();
520 * Set the default number of dynamically learned macs to the number
523 mp->global_learn_limit = L2LEARN_DEFAULT_LIMIT;
528 VLIB_INIT_FUNCTION (l2learn_init);
532 * Set subinterface learn enable/disable.
534 * set interface l2 learn <interface> [disable]
536 static clib_error_t *
537 int_learn (vlib_main_t * vm,
538 unformat_input_t * input, vlib_cli_command_t * cmd)
540 vnet_main_t *vnm = vnet_get_main ();
541 clib_error_t *error = 0;
545 if (!unformat_user (input, unformat_vnet_sw_interface, vnm, &sw_if_index))
547 error = clib_error_return (0, "unknown interface `%U'",
548 format_unformat_error, input);
553 if (unformat (input, "disable"))
558 /* set the interface flag */
559 l2input_intf_bitmap_enable (sw_if_index, L2INPUT_FEAT_LEARN, enable);
566 * Layer 2 learning can be enabled and disabled on each
567 * interface and on each bridge-domain. Use this command to
568 * manage interfaces. It is enabled by default.
571 * Example of how to enable learning:
572 * @cliexcmd{set interface l2 learn GigabitEthernet0/8/0}
573 * Example of how to disable learning:
574 * @cliexcmd{set interface l2 learn GigabitEthernet0/8/0 disable}
577 VLIB_CLI_COMMAND (int_learn_cli, static) = {
578 .path = "set interface l2 learn",
579 .short_help = "set interface l2 learn <interface> [disable]",
580 .function = int_learn,
585 static clib_error_t *
586 l2learn_config (vlib_main_t * vm, unformat_input_t * input)
588 l2learn_main_t *mp = &l2learn_main;
590 while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
592 if (unformat (input, "limit %d", &mp->global_learn_limit))
596 return clib_error_return (0, "unknown input `%U'",
597 format_unformat_error, input);
603 VLIB_CONFIG_FUNCTION (l2learn_config, "l2learn");
609 * fd.io coding-style-patch-verification: ON
612 * eval: (c-set-style "gnu")