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 */
134 if (PREDICT_TRUE (result0->fields.sw_if_index == sw_if_index0))
137 * The entry was in the table, and the sw_if_index matched, the normal case
139 counter_base[L2LEARN_ERROR_HIT] += 1;
140 int update = !result0->fields.static_mac &&
141 (result0->fields.timestamp != timestamp ||
142 result0->fields.sn.as_u16 != vnet_buffer (b0)->l2.l2fib_sn);
144 if (PREDICT_TRUE (!update))
147 else if (result0->raw == ~0)
149 /* 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;
162 /* It is ok to learn */
163 msm->global_learn_count++;
164 result0->raw = 0; /* clear all fields */
165 result0->fields.sw_if_index = sw_if_index0;
166 cached_key->raw = ~0; /* invalidate the cache */
170 /* The entry was in the table, but with the wrong sw_if_index mapping (mac move) */
171 if (result0->fields.filter)
173 ASSERT (result0->fields.sw_if_index == ~0);
174 /* drop packet because lookup matched a filter mac entry */
175 b0->error = node->errors[L2LEARN_ERROR_FILTER_DROP];
176 *next0 = L2LEARN_NEXT_DROP;
180 counter_base[L2LEARN_ERROR_MAC_MOVE] += 1;
182 if (result0->fields.static_mac)
185 * Don't overwrite a static mac
186 * TODO: Check violation policy. For now drop the packet
188 b0->error = node->errors[L2LEARN_ERROR_MAC_MOVE_VIOLATE];
189 *next0 = L2LEARN_NEXT_DROP;
194 * TODO: may want to rate limit mac moves
195 * TODO: check global/bridge domain/interface learn limits
197 result0->fields.sw_if_index = sw_if_index0;
200 /* Update the entry */
201 result0->fields.timestamp = timestamp;
202 result0->fields.sn.as_u16 = vnet_buffer (b0)->l2.l2fib_sn;
204 BVT (clib_bihash_kv) kv;
206 kv.value = result0->raw;
207 BV (clib_bihash_add_del) (msm->mac_table, &kv, 1 /* is_add */ );
211 static_always_inline uword
212 l2learn_node_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
213 vlib_frame_t * frame, int do_trace)
215 u32 n_left_from, *from, *to_next;
216 l2learn_next_t next_index;
217 l2learn_main_t *msm = &l2learn_main;
218 vlib_node_t *n = vlib_get_node (vm, l2learn_node.index);
219 u32 node_counter_base_index = n->error_heap_index;
220 vlib_error_main_t *em = &vm->error_main;
221 l2fib_entry_key_t cached_key;
222 l2fib_entry_result_t cached_result;
223 u8 timestamp = (u8) (vlib_time_now (vm) / 60);
225 from = vlib_frame_vector_args (frame);
226 n_left_from = frame->n_vectors; /* number of packets to process */
227 next_index = node->cached_next_index;
229 /* Clear the one-entry cache in case mac table was updated */
231 cached_result.raw = ~0; /* warning be gone */
233 while (n_left_from > 0)
237 /* get space to enqueue frame to graph node "next_index" */
238 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
240 while (n_left_from >= 8 && n_left_to_next >= 4)
242 u32 bi0, bi1, bi2, bi3;
243 vlib_buffer_t *b0, *b1, *b2, *b3;
244 u32 next0, next1, next2, next3;
245 u32 sw_if_index0, sw_if_index1, sw_if_index2, sw_if_index3;
246 ethernet_header_t *h0, *h1, *h2, *h3;
247 l2fib_entry_key_t key0, key1, key2, key3;
248 l2fib_entry_result_t result0, result1, result2, result3;
249 u32 bucket0, bucket1, bucket2, bucket3;
251 /* Prefetch next iteration. */
253 vlib_buffer_t *p4, *p5, *p6, *p7;;
255 p4 = vlib_get_buffer (vm, from[4]);
256 p5 = vlib_get_buffer (vm, from[5]);
257 p6 = vlib_get_buffer (vm, from[6]);
258 p7 = vlib_get_buffer (vm, from[7]);
260 vlib_prefetch_buffer_header (p4, LOAD);
261 vlib_prefetch_buffer_header (p5, LOAD);
262 vlib_prefetch_buffer_header (p6, LOAD);
263 vlib_prefetch_buffer_header (p7, LOAD);
265 CLIB_PREFETCH (p4->data, CLIB_CACHE_LINE_BYTES, STORE);
266 CLIB_PREFETCH (p5->data, CLIB_CACHE_LINE_BYTES, STORE);
267 CLIB_PREFETCH (p6->data, CLIB_CACHE_LINE_BYTES, STORE);
268 CLIB_PREFETCH (p7->data, CLIB_CACHE_LINE_BYTES, STORE);
271 /* speculatively enqueue b0 and b1 to the current next frame */
272 /* bi is "buffer index", b is pointer to the buffer */
273 to_next[0] = bi0 = from[0];
274 to_next[1] = bi1 = from[1];
275 to_next[2] = bi2 = from[2];
276 to_next[3] = bi3 = from[3];
282 b0 = vlib_get_buffer (vm, bi0);
283 b1 = vlib_get_buffer (vm, bi1);
284 b2 = vlib_get_buffer (vm, bi2);
285 b3 = vlib_get_buffer (vm, bi3);
287 /* RX interface handles */
288 sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
289 sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
290 sw_if_index2 = vnet_buffer (b2)->sw_if_index[VLIB_RX];
291 sw_if_index3 = vnet_buffer (b3)->sw_if_index[VLIB_RX];
293 /* Process 4 x pkts */
295 h0 = vlib_buffer_get_current (b0);
296 h1 = vlib_buffer_get_current (b1);
297 h2 = vlib_buffer_get_current (b2);
298 h3 = vlib_buffer_get_current (b3);
302 if (b0->flags & VLIB_BUFFER_IS_TRACED)
305 vlib_add_trace (vm, node, b0, sizeof (*t));
306 t->sw_if_index = sw_if_index0;
307 t->bd_index = vnet_buffer (b0)->l2.bd_index;
308 clib_memcpy (t->src, h0->src_address, 6);
309 clib_memcpy (t->dst, h0->dst_address, 6);
311 if (b1->flags & VLIB_BUFFER_IS_TRACED)
314 vlib_add_trace (vm, node, b1, sizeof (*t));
315 t->sw_if_index = sw_if_index1;
316 t->bd_index = vnet_buffer (b1)->l2.bd_index;
317 clib_memcpy (t->src, h1->src_address, 6);
318 clib_memcpy (t->dst, h1->dst_address, 6);
320 if (b2->flags & VLIB_BUFFER_IS_TRACED)
323 vlib_add_trace (vm, node, b2, sizeof (*t));
324 t->sw_if_index = sw_if_index2;
325 t->bd_index = vnet_buffer (b2)->l2.bd_index;
326 clib_memcpy (t->src, h2->src_address, 6);
327 clib_memcpy (t->dst, h2->dst_address, 6);
329 if (b3->flags & VLIB_BUFFER_IS_TRACED)
332 vlib_add_trace (vm, node, b3, sizeof (*t));
333 t->sw_if_index = sw_if_index3;
334 t->bd_index = vnet_buffer (b3)->l2.bd_index;
335 clib_memcpy (t->src, h3->src_address, 6);
336 clib_memcpy (t->dst, h3->dst_address, 6);
341 vlib_node_increment_counter (vm, l2learn_node.index,
342 L2LEARN_ERROR_L2LEARN, 4);
344 l2fib_lookup_4 (msm->mac_table, &cached_key, &cached_result,
349 vnet_buffer (b0)->l2.bd_index,
350 vnet_buffer (b1)->l2.bd_index,
351 vnet_buffer (b2)->l2.bd_index,
352 vnet_buffer (b3)->l2.bd_index,
353 &key0, &key1, &key2, &key3,
354 &bucket0, &bucket1, &bucket2, &bucket3,
355 &result0, &result1, &result2, &result3);
357 l2learn_process (node, msm, &em->counters[node_counter_base_index],
358 b0, sw_if_index0, &key0, &cached_key,
359 &bucket0, &result0, &next0, timestamp);
361 l2learn_process (node, msm, &em->counters[node_counter_base_index],
362 b1, sw_if_index1, &key1, &cached_key,
363 &bucket1, &result1, &next1, timestamp);
365 l2learn_process (node, msm, &em->counters[node_counter_base_index],
366 b2, sw_if_index2, &key2, &cached_key,
367 &bucket2, &result2, &next2, timestamp);
369 l2learn_process (node, msm, &em->counters[node_counter_base_index],
370 b3, sw_if_index3, &key3, &cached_key,
371 &bucket3, &result3, &next3, timestamp);
373 /* verify speculative enqueues, maybe switch current next frame */
374 /* if next0==next1==next_index then nothing special needs to be done */
375 vlib_validate_buffer_enqueue_x4 (vm, node, next_index,
376 to_next, n_left_to_next,
378 next0, next1, next2, next3);
381 while (n_left_from > 0 && n_left_to_next > 0)
387 ethernet_header_t *h0;
388 l2fib_entry_key_t key0;
389 l2fib_entry_result_t result0;
392 /* speculatively enqueue b0 to the current next frame */
400 b0 = vlib_get_buffer (vm, bi0);
402 sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
404 h0 = vlib_buffer_get_current (b0);
406 if (do_trace && PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
408 l2learn_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
409 t->sw_if_index = sw_if_index0;
410 t->bd_index = vnet_buffer (b0)->l2.bd_index;
411 clib_memcpy (t->src, h0->src_address, 6);
412 clib_memcpy (t->dst, h0->dst_address, 6);
416 vlib_node_increment_counter (vm, l2learn_node.index,
417 L2LEARN_ERROR_L2LEARN, 1);
420 l2fib_lookup_1 (msm->mac_table, &cached_key, &cached_result,
421 h0->src_address, vnet_buffer (b0)->l2.bd_index,
422 &key0, &bucket0, &result0);
424 l2learn_process (node, msm, &em->counters[node_counter_base_index],
425 b0, sw_if_index0, &key0, &cached_key,
426 &bucket0, &result0, &next0, timestamp);
428 /* verify speculative enqueue, maybe switch current next frame */
429 vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
430 to_next, n_left_to_next,
434 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
437 return frame->n_vectors;
441 l2learn_node_fn (vlib_main_t * vm,
442 vlib_node_runtime_t * node, vlib_frame_t * frame)
444 if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)))
445 return l2learn_node_inline (vm, node, frame, 1 /* do_trace */ );
446 return l2learn_node_inline (vm, node, frame, 0 /* do_trace */ );
450 VLIB_REGISTER_NODE (l2learn_node,static) = {
451 .function = l2learn_node_fn,
453 .vector_size = sizeof (u32),
454 .format_trace = format_l2learn_trace,
455 .type = VLIB_NODE_TYPE_INTERNAL,
457 .n_errors = ARRAY_LEN(l2learn_error_strings),
458 .error_strings = l2learn_error_strings,
460 .n_next_nodes = L2LEARN_N_NEXT,
462 /* edit / add dispositions here */
464 [L2LEARN_NEXT_DROP] = "error-drop",
465 [L2LEARN_NEXT_L2FWD] = "l2-fwd",
470 VLIB_NODE_FUNCTION_MULTIARCH (l2learn_node, l2learn_node_fn)
471 clib_error_t *l2learn_init (vlib_main_t * vm)
473 l2learn_main_t *mp = &l2learn_main;
476 mp->vnet_main = vnet_get_main ();
478 /* Initialize the feature next-node indexes */
479 feat_bitmap_init_next_nodes (vm,
482 l2input_get_feat_names (),
483 mp->feat_next_node_index);
485 /* init the hash table ptr */
486 mp->mac_table = get_mac_table ();
489 * Set the default number of dynamically learned macs to the number
492 mp->global_learn_limit = L2FIB_NUM_BUCKETS * 16;
497 VLIB_INIT_FUNCTION (l2learn_init);
501 * Set subinterface learn enable/disable.
503 * set interface l2 learn <interface> [disable]
505 static clib_error_t *
506 int_learn (vlib_main_t * vm,
507 unformat_input_t * input, vlib_cli_command_t * cmd)
509 vnet_main_t *vnm = vnet_get_main ();
510 clib_error_t *error = 0;
514 if (!unformat_user (input, unformat_vnet_sw_interface, vnm, &sw_if_index))
516 error = clib_error_return (0, "unknown interface `%U'",
517 format_unformat_error, input);
522 if (unformat (input, "disable"))
527 /* set the interface flag */
528 l2input_intf_bitmap_enable (sw_if_index, L2INPUT_FEAT_LEARN, enable);
535 * Layer 2 learning can be enabled and disabled on each
536 * interface and on each bridge-domain. Use this command to
537 * manage interfaces. It is enabled by default.
540 * Example of how to enable learning:
541 * @cliexcmd{set interface l2 learn GigabitEthernet0/8/0}
542 * Example of how to disable learning:
543 * @cliexcmd{set interface l2 learn GigabitEthernet0/8/0 disable}
546 VLIB_CLI_COMMAND (int_learn_cli, static) = {
547 .path = "set interface l2 learn",
548 .short_help = "set interface l2 learn <interface> [disable]",
549 .function = int_learn,
554 static clib_error_t *
555 l2learn_config (vlib_main_t * vm, unformat_input_t * input)
557 l2learn_main_t *mp = &l2learn_main;
559 while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
561 if (unformat (input, "limit %d", &mp->global_learn_limit))
565 return clib_error_return (0, "unknown input `%U'",
566 format_unformat_error, input);
572 VLIB_CONFIG_FUNCTION (l2learn_config, "l2learn");
576 * fd.io coding-style-patch-verification: ON
579 * eval: (c-set-style "gnu")