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 l2learn_main_t l2learn_main;
36 * @brief Ethernet Bridge Learning.
38 * Populate the mac table with entries mapping the packet's source mac + bridge
39 * domain ID to the input sw_if_index.
41 * Note that learning and forwarding are separate graph nodes. This means that
42 * for a set of packets, all learning is performed first, then all nodes are
43 * forwarded. The forwarding is done based on the end-state of the mac table,
44 * instead of the state after each packet. Thus the forwarding results could
45 * differ in certain cases (mac move tests), but this not expected to cause
46 * problems in real-world networks. It is much simpler to separate learning
47 * and forwarding into separate nodes.
60 /* packet trace format function */
62 format_l2learn_trace (u8 * s, va_list * args)
64 CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
65 CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
66 l2learn_trace_t *t = va_arg (*args, l2learn_trace_t *);
68 s = format (s, "l2-learn: sw_if_index %d dst %U src %U bd_index %d",
70 format_ethernet_address, t->dst,
71 format_ethernet_address, t->src, t->bd_index);
75 static vlib_node_registration_t l2learn_node;
77 #define foreach_l2learn_error \
78 _(L2LEARN, "L2 learn packets") \
79 _(MISS, "L2 learn misses") \
80 _(MAC_MOVE, "L2 mac moves") \
81 _(MAC_MOVE_VIOLATE, "L2 mac move violations") \
82 _(LIMIT, "L2 not learned due to limit") \
83 _(HIT_UPDATE, "L2 learn hit updates") \
84 _(FILTER_DROP, "L2 filter mac drops")
88 #define _(sym,str) L2LEARN_ERROR_##sym,
94 static char *l2learn_error_strings[] = {
95 #define _(sym,string) string,
108 /** Perform learning on one packet based on the mac table lookup result. */
110 static_always_inline void
111 l2learn_process (vlib_node_runtime_t * node,
112 l2learn_main_t * msm,
116 l2fib_entry_key_t * key0,
117 l2fib_entry_key_t * cached_key,
119 l2fib_entry_result_t * result0, u32 * next0, u8 timestamp)
121 /* Set up the default next node (typically L2FWD) */
122 *next0 = vnet_l2_feature_next (b0, msm->feat_next_node_index,
125 /* Check mac table lookup result */
126 if (PREDICT_TRUE (result0->fields.sw_if_index == sw_if_index0))
128 /* Entry in L2FIB with matching sw_if_index matched - normal fast path */
129 u32 dtime = timestamp - result0->fields.timestamp;
130 u32 dsn = result0->fields.sn.as_u16 - vnet_buffer (b0)->l2.l2fib_sn;
131 u32 check = (dtime && vnet_buffer (b0)->l2.bd_age) || dsn;
133 if (PREDICT_TRUE (check == 0))
134 return; /* MAC entry up to date */
135 if (result0->fields.age_not)
136 return; /* Static MAC always age_not */
137 if (msm->global_learn_count > msm->global_learn_limit)
138 return; /* Above learn limit - do not update */
140 /* Limit updates per l2-learn node call to avoid prolonged update burst
141 * as dtime advance over 1 minute mark, unless more than 1 min behind
143 if ((*count > 2) && (dtime == 1) && (dsn == 0))
146 counter_base[L2LEARN_ERROR_HIT_UPDATE] += 1;
149 else if (result0->raw == ~0)
151 /* Entry not in L2FIB - add it */
152 counter_base[L2LEARN_ERROR_MISS] += 1;
154 if (msm->global_learn_count >= msm->global_learn_limit)
157 * Global limit reached. Do not learn the mac but forward the packet.
158 * In the future, limits could also be per-interface or bridge-domain.
160 counter_base[L2LEARN_ERROR_LIMIT] += 1;
164 /* Do not learn if mac is 0 */
165 l2fib_entry_key_t key = *key0;
166 key.fields.bd_index = 0;
170 /* It is ok to learn */
171 msm->global_learn_count++;
172 result0->raw = 0; /* clear all fields */
173 result0->fields.sw_if_index = sw_if_index0;
174 result0->fields.lrn_evt = (msm->client_pid != 0);
178 /* Entry in L2FIB with different sw_if_index - mac move or filter */
179 if (result0->fields.filter)
181 ASSERT (result0->fields.sw_if_index == ~0);
182 /* drop packet because lookup matched a filter mac entry */
183 b0->error = node->errors[L2LEARN_ERROR_FILTER_DROP];
184 *next0 = L2LEARN_NEXT_DROP;
188 if (result0->fields.static_mac)
191 * Don't overwrite a static mac
192 * TODO: Check violation policy. For now drop the packet
194 b0->error = node->errors[L2LEARN_ERROR_MAC_MOVE_VIOLATE];
195 *next0 = L2LEARN_NEXT_DROP;
200 * TODO: may want to rate limit mac moves
201 * TODO: check global/bridge domain/interface learn limits
203 result0->fields.sw_if_index = sw_if_index0;
204 if (result0->fields.age_not) /* The mac was provisioned */
206 msm->global_learn_count++;
207 result0->fields.age_not = 0;
209 result0->fields.lrn_evt = (msm->client_pid != 0);
210 result0->fields.lrn_mov = (msm->client_pid != 0);
211 counter_base[L2LEARN_ERROR_MAC_MOVE] += 1;
214 /* Update the entry */
215 result0->fields.timestamp = timestamp;
216 result0->fields.sn.as_u16 = vnet_buffer (b0)->l2.l2fib_sn;
218 BVT (clib_bihash_kv) kv;
220 kv.value = result0->raw;
221 BV (clib_bihash_add_del) (msm->mac_table, &kv, 1 /* is_add */ );
223 /* Invalidate the cache */
224 cached_key->raw = ~0;
228 static_always_inline uword
229 l2learn_node_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
230 vlib_frame_t * frame, int do_trace)
232 u32 n_left_from, *from, *to_next;
233 l2learn_next_t next_index;
234 l2learn_main_t *msm = &l2learn_main;
235 vlib_node_t *n = vlib_get_node (vm, l2learn_node.index);
236 u32 node_counter_base_index = n->error_heap_index;
237 vlib_error_main_t *em = &vm->error_main;
238 l2fib_entry_key_t cached_key;
239 l2fib_entry_result_t cached_result;
240 u8 timestamp = (u8) (vlib_time_now (vm) / 60);
243 from = vlib_frame_vector_args (frame);
244 n_left_from = frame->n_vectors; /* number of packets to process */
245 next_index = node->cached_next_index;
247 /* Clear the one-entry cache in case mac table was updated */
249 cached_result.raw = ~0; /* warning be gone */
251 while (n_left_from > 0)
255 /* get space to enqueue frame to graph node "next_index" */
256 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
258 while (n_left_from >= 8 && n_left_to_next >= 4)
260 u32 bi0, bi1, bi2, bi3;
261 vlib_buffer_t *b0, *b1, *b2, *b3;
262 u32 next0, next1, next2, next3;
263 u32 sw_if_index0, sw_if_index1, sw_if_index2, sw_if_index3;
264 ethernet_header_t *h0, *h1, *h2, *h3;
265 l2fib_entry_key_t key0, key1, key2, key3;
266 l2fib_entry_result_t result0, result1, result2, result3;
267 u32 bucket0, bucket1, bucket2, bucket3;
269 /* Prefetch next iteration. */
271 vlib_buffer_t *p4, *p5, *p6, *p7;;
273 p4 = vlib_get_buffer (vm, from[4]);
274 p5 = vlib_get_buffer (vm, from[5]);
275 p6 = vlib_get_buffer (vm, from[6]);
276 p7 = vlib_get_buffer (vm, from[7]);
278 vlib_prefetch_buffer_header (p4, LOAD);
279 vlib_prefetch_buffer_header (p5, LOAD);
280 vlib_prefetch_buffer_header (p6, LOAD);
281 vlib_prefetch_buffer_header (p7, LOAD);
283 CLIB_PREFETCH (p4->data, CLIB_CACHE_LINE_BYTES, STORE);
284 CLIB_PREFETCH (p5->data, CLIB_CACHE_LINE_BYTES, STORE);
285 CLIB_PREFETCH (p6->data, CLIB_CACHE_LINE_BYTES, STORE);
286 CLIB_PREFETCH (p7->data, CLIB_CACHE_LINE_BYTES, STORE);
289 /* speculatively enqueue b0 and b1 to the current next frame */
290 /* bi is "buffer index", b is pointer to the buffer */
291 to_next[0] = bi0 = from[0];
292 to_next[1] = bi1 = from[1];
293 to_next[2] = bi2 = from[2];
294 to_next[3] = bi3 = from[3];
300 b0 = vlib_get_buffer (vm, bi0);
301 b1 = vlib_get_buffer (vm, bi1);
302 b2 = vlib_get_buffer (vm, bi2);
303 b3 = vlib_get_buffer (vm, bi3);
305 /* RX interface handles */
306 sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
307 sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
308 sw_if_index2 = vnet_buffer (b2)->sw_if_index[VLIB_RX];
309 sw_if_index3 = vnet_buffer (b3)->sw_if_index[VLIB_RX];
311 /* Process 4 x pkts */
313 h0 = vlib_buffer_get_current (b0);
314 h1 = vlib_buffer_get_current (b1);
315 h2 = vlib_buffer_get_current (b2);
316 h3 = vlib_buffer_get_current (b3);
320 if (b0->flags & VLIB_BUFFER_IS_TRACED)
323 vlib_add_trace (vm, node, b0, sizeof (*t));
324 t->sw_if_index = sw_if_index0;
325 t->bd_index = vnet_buffer (b0)->l2.bd_index;
326 clib_memcpy (t->src, h0->src_address, 6);
327 clib_memcpy (t->dst, h0->dst_address, 6);
329 if (b1->flags & VLIB_BUFFER_IS_TRACED)
332 vlib_add_trace (vm, node, b1, sizeof (*t));
333 t->sw_if_index = sw_if_index1;
334 t->bd_index = vnet_buffer (b1)->l2.bd_index;
335 clib_memcpy (t->src, h1->src_address, 6);
336 clib_memcpy (t->dst, h1->dst_address, 6);
338 if (b2->flags & VLIB_BUFFER_IS_TRACED)
341 vlib_add_trace (vm, node, b2, sizeof (*t));
342 t->sw_if_index = sw_if_index2;
343 t->bd_index = vnet_buffer (b2)->l2.bd_index;
344 clib_memcpy (t->src, h2->src_address, 6);
345 clib_memcpy (t->dst, h2->dst_address, 6);
347 if (b3->flags & VLIB_BUFFER_IS_TRACED)
350 vlib_add_trace (vm, node, b3, sizeof (*t));
351 t->sw_if_index = sw_if_index3;
352 t->bd_index = vnet_buffer (b3)->l2.bd_index;
353 clib_memcpy (t->src, h3->src_address, 6);
354 clib_memcpy (t->dst, h3->dst_address, 6);
359 vlib_node_increment_counter (vm, l2learn_node.index,
360 L2LEARN_ERROR_L2LEARN, 4);
362 l2fib_lookup_4 (msm->mac_table, &cached_key, &cached_result,
367 vnet_buffer (b0)->l2.bd_index,
368 vnet_buffer (b1)->l2.bd_index,
369 vnet_buffer (b2)->l2.bd_index,
370 vnet_buffer (b3)->l2.bd_index,
371 &key0, &key1, &key2, &key3,
372 &bucket0, &bucket1, &bucket2, &bucket3,
373 &result0, &result1, &result2, &result3);
375 l2learn_process (node, msm, &em->counters[node_counter_base_index],
376 b0, sw_if_index0, &key0, &cached_key,
377 &count, &result0, &next0, timestamp);
379 l2learn_process (node, msm, &em->counters[node_counter_base_index],
380 b1, sw_if_index1, &key1, &cached_key,
381 &count, &result1, &next1, timestamp);
383 l2learn_process (node, msm, &em->counters[node_counter_base_index],
384 b2, sw_if_index2, &key2, &cached_key,
385 &count, &result2, &next2, timestamp);
387 l2learn_process (node, msm, &em->counters[node_counter_base_index],
388 b3, sw_if_index3, &key3, &cached_key,
389 &count, &result3, &next3, timestamp);
391 /* verify speculative enqueues, maybe switch current next frame */
392 /* if next0==next1==next_index then nothing special needs to be done */
393 vlib_validate_buffer_enqueue_x4 (vm, node, next_index,
394 to_next, n_left_to_next,
396 next0, next1, next2, next3);
399 while (n_left_from > 0 && n_left_to_next > 0)
405 ethernet_header_t *h0;
406 l2fib_entry_key_t key0;
407 l2fib_entry_result_t result0;
410 /* speculatively enqueue b0 to the current next frame */
418 b0 = vlib_get_buffer (vm, bi0);
420 sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
422 h0 = vlib_buffer_get_current (b0);
424 if (do_trace && PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
426 l2learn_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
427 t->sw_if_index = sw_if_index0;
428 t->bd_index = vnet_buffer (b0)->l2.bd_index;
429 clib_memcpy (t->src, h0->src_address, 6);
430 clib_memcpy (t->dst, h0->dst_address, 6);
434 vlib_node_increment_counter (vm, l2learn_node.index,
435 L2LEARN_ERROR_L2LEARN, 1);
438 l2fib_lookup_1 (msm->mac_table, &cached_key, &cached_result,
439 h0->src_address, vnet_buffer (b0)->l2.bd_index,
440 &key0, &bucket0, &result0);
442 l2learn_process (node, msm, &em->counters[node_counter_base_index],
443 b0, sw_if_index0, &key0, &cached_key,
444 &count, &result0, &next0, timestamp);
446 /* verify speculative enqueue, maybe switch current next frame */
447 vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
448 to_next, n_left_to_next,
452 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
455 return frame->n_vectors;
459 l2learn_node_fn (vlib_main_t * vm,
460 vlib_node_runtime_t * node, vlib_frame_t * frame)
462 if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)))
463 return l2learn_node_inline (vm, node, frame, 1 /* do_trace */ );
464 return l2learn_node_inline (vm, node, frame, 0 /* do_trace */ );
468 VLIB_REGISTER_NODE (l2learn_node,static) = {
469 .function = l2learn_node_fn,
471 .vector_size = sizeof (u32),
472 .format_trace = format_l2learn_trace,
473 .type = VLIB_NODE_TYPE_INTERNAL,
475 .n_errors = ARRAY_LEN(l2learn_error_strings),
476 .error_strings = l2learn_error_strings,
478 .n_next_nodes = L2LEARN_N_NEXT,
480 /* edit / add dispositions here */
482 [L2LEARN_NEXT_DROP] = "error-drop",
483 [L2LEARN_NEXT_L2FWD] = "l2-fwd",
488 VLIB_NODE_FUNCTION_MULTIARCH (l2learn_node, l2learn_node_fn)
489 clib_error_t *l2learn_init (vlib_main_t * vm)
491 l2learn_main_t *mp = &l2learn_main;
494 mp->vnet_main = vnet_get_main ();
496 /* Initialize the feature next-node indexes */
497 feat_bitmap_init_next_nodes (vm,
500 l2input_get_feat_names (),
501 mp->feat_next_node_index);
503 /* init the hash table ptr */
504 mp->mac_table = get_mac_table ();
507 * Set the default number of dynamically learned macs to the number
510 mp->global_learn_limit = L2LEARN_DEFAULT_LIMIT;
515 VLIB_INIT_FUNCTION (l2learn_init);
519 * Set subinterface learn enable/disable.
521 * set interface l2 learn <interface> [disable]
523 static clib_error_t *
524 int_learn (vlib_main_t * vm,
525 unformat_input_t * input, vlib_cli_command_t * cmd)
527 vnet_main_t *vnm = vnet_get_main ();
528 clib_error_t *error = 0;
532 if (!unformat_user (input, unformat_vnet_sw_interface, vnm, &sw_if_index))
534 error = clib_error_return (0, "unknown interface `%U'",
535 format_unformat_error, input);
540 if (unformat (input, "disable"))
545 /* set the interface flag */
546 l2input_intf_bitmap_enable (sw_if_index, L2INPUT_FEAT_LEARN, enable);
553 * Layer 2 learning can be enabled and disabled on each
554 * interface and on each bridge-domain. Use this command to
555 * manage interfaces. It is enabled by default.
558 * Example of how to enable learning:
559 * @cliexcmd{set interface l2 learn GigabitEthernet0/8/0}
560 * Example of how to disable learning:
561 * @cliexcmd{set interface l2 learn GigabitEthernet0/8/0 disable}
564 VLIB_CLI_COMMAND (int_learn_cli, static) = {
565 .path = "set interface l2 learn",
566 .short_help = "set interface l2 learn <interface> [disable]",
567 .function = int_learn,
572 static clib_error_t *
573 l2learn_config (vlib_main_t * vm, unformat_input_t * input)
575 l2learn_main_t *mp = &l2learn_main;
577 while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
579 if (unformat (input, "limit %d", &mp->global_learn_limit))
583 return clib_error_return (0, "unknown input `%U'",
584 format_unformat_error, input);
590 VLIB_CONFIG_FUNCTION (l2learn_config, "l2learn");
594 * fd.io coding-style-patch-verification: ON
597 * eval: (c-set-style "gnu")