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_UPDATE, "L2 learn hit updates") \
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))
126 /* Entry in L2FIB with matching sw_if_index matched - normal fast path */
127 u32 dtime = timestamp - result0->fields.timestamp;
128 u32 dsn = result0->fields.sn.as_u16 - vnet_buffer (b0)->l2.l2fib_sn;
129 u32 check = dtime | dsn;
131 if (PREDICT_TRUE (check == 0))
132 return; /* MAC entry up to date */
133 if (result0->fields.age_not)
134 return; /* Static MAC always age_not */
135 if (msm->global_learn_count > msm->global_learn_limit)
136 return; /* Above learn limit - do not update */
138 /* Limit updates per l2-learn node call to avoid prolonged update burst
139 * as dtime advance over 1 minute mark, unless more than 1 min behind */
140 if ((*count > 2) && (dtime == 1))
143 counter_base[L2LEARN_ERROR_HIT_UPDATE] += 1;
146 else if (result0->raw == ~0)
148 /* Entry not in L2FIB - add it */
149 counter_base[L2LEARN_ERROR_MISS] += 1;
151 if (msm->global_learn_count >= msm->global_learn_limit)
154 * Global limit reached. Do not learn the mac but forward the packet.
155 * In the future, limits could also be per-interface or bridge-domain.
157 counter_base[L2LEARN_ERROR_LIMIT] += 1;
161 /* Do not learn if mac is 0 */
162 l2fib_entry_key_t key = *key0;
163 key.fields.bd_index = 0;
167 /* It is ok to learn */
168 msm->global_learn_count++;
169 result0->raw = 0; /* clear all fields */
170 result0->fields.sw_if_index = sw_if_index0;
171 result0->fields.lrn_evt = (msm->client_pid != 0);
175 /* Entry in L2FIB with different sw_if_index - mac move or filter */
176 if (result0->fields.filter)
178 ASSERT (result0->fields.sw_if_index == ~0);
179 /* drop packet because lookup matched a filter mac entry */
180 b0->error = node->errors[L2LEARN_ERROR_FILTER_DROP];
181 *next0 = L2LEARN_NEXT_DROP;
185 if (result0->fields.static_mac)
188 * Don't overwrite a static mac
189 * TODO: Check violation policy. For now drop the packet
191 b0->error = node->errors[L2LEARN_ERROR_MAC_MOVE_VIOLATE];
192 *next0 = L2LEARN_NEXT_DROP;
197 * TODO: may want to rate limit mac moves
198 * TODO: check global/bridge domain/interface learn limits
200 result0->fields.sw_if_index = sw_if_index0;
201 if (result0->fields.age_not) /* The mac was provisioned */
203 msm->global_learn_count++;
204 result0->fields.age_not = 0;
206 result0->fields.lrn_evt = (msm->client_pid != 0);
207 counter_base[L2LEARN_ERROR_MAC_MOVE] += 1;
210 /* Update the entry */
211 result0->fields.timestamp = timestamp;
212 result0->fields.sn.as_u16 = vnet_buffer (b0)->l2.l2fib_sn;
214 BVT (clib_bihash_kv) kv;
216 kv.value = result0->raw;
217 BV (clib_bihash_add_del) (msm->mac_table, &kv, 1 /* is_add */ );
219 /* Invalidate the cache */
220 cached_key->raw = ~0;
224 static_always_inline uword
225 l2learn_node_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
226 vlib_frame_t * frame, int do_trace)
228 u32 n_left_from, *from, *to_next;
229 l2learn_next_t next_index;
230 l2learn_main_t *msm = &l2learn_main;
231 vlib_node_t *n = vlib_get_node (vm, l2learn_node.index);
232 u32 node_counter_base_index = n->error_heap_index;
233 vlib_error_main_t *em = &vm->error_main;
234 l2fib_entry_key_t cached_key;
235 l2fib_entry_result_t cached_result;
236 u8 timestamp = (u8) (vlib_time_now (vm) / 60);
239 from = vlib_frame_vector_args (frame);
240 n_left_from = frame->n_vectors; /* number of packets to process */
241 next_index = node->cached_next_index;
243 /* Clear the one-entry cache in case mac table was updated */
245 cached_result.raw = ~0; /* warning be gone */
247 while (n_left_from > 0)
251 /* get space to enqueue frame to graph node "next_index" */
252 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
254 while (n_left_from >= 8 && n_left_to_next >= 4)
256 u32 bi0, bi1, bi2, bi3;
257 vlib_buffer_t *b0, *b1, *b2, *b3;
258 u32 next0, next1, next2, next3;
259 u32 sw_if_index0, sw_if_index1, sw_if_index2, sw_if_index3;
260 ethernet_header_t *h0, *h1, *h2, *h3;
261 l2fib_entry_key_t key0, key1, key2, key3;
262 l2fib_entry_result_t result0, result1, result2, result3;
263 u32 bucket0, bucket1, bucket2, bucket3;
265 /* Prefetch next iteration. */
267 vlib_buffer_t *p4, *p5, *p6, *p7;;
269 p4 = vlib_get_buffer (vm, from[4]);
270 p5 = vlib_get_buffer (vm, from[5]);
271 p6 = vlib_get_buffer (vm, from[6]);
272 p7 = vlib_get_buffer (vm, from[7]);
274 vlib_prefetch_buffer_header (p4, LOAD);
275 vlib_prefetch_buffer_header (p5, LOAD);
276 vlib_prefetch_buffer_header (p6, LOAD);
277 vlib_prefetch_buffer_header (p7, LOAD);
279 CLIB_PREFETCH (p4->data, CLIB_CACHE_LINE_BYTES, STORE);
280 CLIB_PREFETCH (p5->data, CLIB_CACHE_LINE_BYTES, STORE);
281 CLIB_PREFETCH (p6->data, CLIB_CACHE_LINE_BYTES, STORE);
282 CLIB_PREFETCH (p7->data, CLIB_CACHE_LINE_BYTES, STORE);
285 /* speculatively enqueue b0 and b1 to the current next frame */
286 /* bi is "buffer index", b is pointer to the buffer */
287 to_next[0] = bi0 = from[0];
288 to_next[1] = bi1 = from[1];
289 to_next[2] = bi2 = from[2];
290 to_next[3] = bi3 = from[3];
296 b0 = vlib_get_buffer (vm, bi0);
297 b1 = vlib_get_buffer (vm, bi1);
298 b2 = vlib_get_buffer (vm, bi2);
299 b3 = vlib_get_buffer (vm, bi3);
301 /* RX interface handles */
302 sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
303 sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
304 sw_if_index2 = vnet_buffer (b2)->sw_if_index[VLIB_RX];
305 sw_if_index3 = vnet_buffer (b3)->sw_if_index[VLIB_RX];
307 /* Process 4 x pkts */
309 h0 = vlib_buffer_get_current (b0);
310 h1 = vlib_buffer_get_current (b1);
311 h2 = vlib_buffer_get_current (b2);
312 h3 = vlib_buffer_get_current (b3);
316 if (b0->flags & VLIB_BUFFER_IS_TRACED)
319 vlib_add_trace (vm, node, b0, sizeof (*t));
320 t->sw_if_index = sw_if_index0;
321 t->bd_index = vnet_buffer (b0)->l2.bd_index;
322 clib_memcpy (t->src, h0->src_address, 6);
323 clib_memcpy (t->dst, h0->dst_address, 6);
325 if (b1->flags & VLIB_BUFFER_IS_TRACED)
328 vlib_add_trace (vm, node, b1, sizeof (*t));
329 t->sw_if_index = sw_if_index1;
330 t->bd_index = vnet_buffer (b1)->l2.bd_index;
331 clib_memcpy (t->src, h1->src_address, 6);
332 clib_memcpy (t->dst, h1->dst_address, 6);
334 if (b2->flags & VLIB_BUFFER_IS_TRACED)
337 vlib_add_trace (vm, node, b2, sizeof (*t));
338 t->sw_if_index = sw_if_index2;
339 t->bd_index = vnet_buffer (b2)->l2.bd_index;
340 clib_memcpy (t->src, h2->src_address, 6);
341 clib_memcpy (t->dst, h2->dst_address, 6);
343 if (b3->flags & VLIB_BUFFER_IS_TRACED)
346 vlib_add_trace (vm, node, b3, sizeof (*t));
347 t->sw_if_index = sw_if_index3;
348 t->bd_index = vnet_buffer (b3)->l2.bd_index;
349 clib_memcpy (t->src, h3->src_address, 6);
350 clib_memcpy (t->dst, h3->dst_address, 6);
355 vlib_node_increment_counter (vm, l2learn_node.index,
356 L2LEARN_ERROR_L2LEARN, 4);
358 l2fib_lookup_4 (msm->mac_table, &cached_key, &cached_result,
363 vnet_buffer (b0)->l2.bd_index,
364 vnet_buffer (b1)->l2.bd_index,
365 vnet_buffer (b2)->l2.bd_index,
366 vnet_buffer (b3)->l2.bd_index,
367 &key0, &key1, &key2, &key3,
368 &bucket0, &bucket1, &bucket2, &bucket3,
369 &result0, &result1, &result2, &result3);
371 l2learn_process (node, msm, &em->counters[node_counter_base_index],
372 b0, sw_if_index0, &key0, &cached_key,
373 &count, &result0, &next0, timestamp);
375 l2learn_process (node, msm, &em->counters[node_counter_base_index],
376 b1, sw_if_index1, &key1, &cached_key,
377 &count, &result1, &next1, timestamp);
379 l2learn_process (node, msm, &em->counters[node_counter_base_index],
380 b2, sw_if_index2, &key2, &cached_key,
381 &count, &result2, &next2, timestamp);
383 l2learn_process (node, msm, &em->counters[node_counter_base_index],
384 b3, sw_if_index3, &key3, &cached_key,
385 &count, &result3, &next3, timestamp);
387 /* verify speculative enqueues, maybe switch current next frame */
388 /* if next0==next1==next_index then nothing special needs to be done */
389 vlib_validate_buffer_enqueue_x4 (vm, node, next_index,
390 to_next, n_left_to_next,
392 next0, next1, next2, next3);
395 while (n_left_from > 0 && n_left_to_next > 0)
401 ethernet_header_t *h0;
402 l2fib_entry_key_t key0;
403 l2fib_entry_result_t result0;
406 /* speculatively enqueue b0 to the current next frame */
414 b0 = vlib_get_buffer (vm, bi0);
416 sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
418 h0 = vlib_buffer_get_current (b0);
420 if (do_trace && PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
422 l2learn_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
423 t->sw_if_index = sw_if_index0;
424 t->bd_index = vnet_buffer (b0)->l2.bd_index;
425 clib_memcpy (t->src, h0->src_address, 6);
426 clib_memcpy (t->dst, h0->dst_address, 6);
430 vlib_node_increment_counter (vm, l2learn_node.index,
431 L2LEARN_ERROR_L2LEARN, 1);
434 l2fib_lookup_1 (msm->mac_table, &cached_key, &cached_result,
435 h0->src_address, vnet_buffer (b0)->l2.bd_index,
436 &key0, &bucket0, &result0);
438 l2learn_process (node, msm, &em->counters[node_counter_base_index],
439 b0, sw_if_index0, &key0, &cached_key,
440 &count, &result0, &next0, timestamp);
442 /* verify speculative enqueue, maybe switch current next frame */
443 vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
444 to_next, n_left_to_next,
448 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
451 return frame->n_vectors;
455 l2learn_node_fn (vlib_main_t * vm,
456 vlib_node_runtime_t * node, vlib_frame_t * frame)
458 if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)))
459 return l2learn_node_inline (vm, node, frame, 1 /* do_trace */ );
460 return l2learn_node_inline (vm, node, frame, 0 /* do_trace */ );
464 VLIB_REGISTER_NODE (l2learn_node,static) = {
465 .function = l2learn_node_fn,
467 .vector_size = sizeof (u32),
468 .format_trace = format_l2learn_trace,
469 .type = VLIB_NODE_TYPE_INTERNAL,
471 .n_errors = ARRAY_LEN(l2learn_error_strings),
472 .error_strings = l2learn_error_strings,
474 .n_next_nodes = L2LEARN_N_NEXT,
476 /* edit / add dispositions here */
478 [L2LEARN_NEXT_DROP] = "error-drop",
479 [L2LEARN_NEXT_L2FWD] = "l2-fwd",
484 VLIB_NODE_FUNCTION_MULTIARCH (l2learn_node, l2learn_node_fn)
485 clib_error_t *l2learn_init (vlib_main_t * vm)
487 l2learn_main_t *mp = &l2learn_main;
490 mp->vnet_main = vnet_get_main ();
492 /* Initialize the feature next-node indexes */
493 feat_bitmap_init_next_nodes (vm,
496 l2input_get_feat_names (),
497 mp->feat_next_node_index);
499 /* init the hash table ptr */
500 mp->mac_table = get_mac_table ();
503 * Set the default number of dynamically learned macs to the number
506 mp->global_learn_limit = L2LEARN_DEFAULT_LIMIT;
511 VLIB_INIT_FUNCTION (l2learn_init);
515 * Set subinterface learn enable/disable.
517 * set interface l2 learn <interface> [disable]
519 static clib_error_t *
520 int_learn (vlib_main_t * vm,
521 unformat_input_t * input, vlib_cli_command_t * cmd)
523 vnet_main_t *vnm = vnet_get_main ();
524 clib_error_t *error = 0;
528 if (!unformat_user (input, unformat_vnet_sw_interface, vnm, &sw_if_index))
530 error = clib_error_return (0, "unknown interface `%U'",
531 format_unformat_error, input);
536 if (unformat (input, "disable"))
541 /* set the interface flag */
542 l2input_intf_bitmap_enable (sw_if_index, L2INPUT_FEAT_LEARN, enable);
549 * Layer 2 learning can be enabled and disabled on each
550 * interface and on each bridge-domain. Use this command to
551 * manage interfaces. It is enabled by default.
554 * Example of how to enable learning:
555 * @cliexcmd{set interface l2 learn GigabitEthernet0/8/0}
556 * Example of how to disable learning:
557 * @cliexcmd{set interface l2 learn GigabitEthernet0/8/0 disable}
560 VLIB_CLI_COMMAND (int_learn_cli, static) = {
561 .path = "set interface l2 learn",
562 .short_help = "set interface l2 learn <interface> [disable]",
563 .function = int_learn,
568 static clib_error_t *
569 l2learn_config (vlib_main_t * vm, unformat_input_t * input)
571 l2learn_main_t *mp = &l2learn_main;
573 while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
575 if (unformat (input, "limit %d", &mp->global_learn_limit))
579 return clib_error_return (0, "unknown input `%U'",
580 format_unformat_error, input);
586 VLIB_CONFIG_FUNCTION (l2learn_config, "l2learn");
590 * fd.io coding-style-patch-verification: ON
593 * eval: (c-set-style "gnu")