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,
116 u32 * bucket0, l2fib_entry_result_t * result0, u32 * next0)
120 /* Set up the default next node (typically L2FWD) */
122 /* Remove ourself from the feature bitmap */
123 feature_bitmap = vnet_buffer (b0)->l2.feature_bitmap & ~L2INPUT_FEAT_LEARN;
125 /* Save for next feature graph nodes */
126 vnet_buffer (b0)->l2.feature_bitmap = feature_bitmap;
128 /* Determine the next node */
129 *next0 = feat_bitmap_get_next_node_index (msm->feat_next_node_index,
132 /* 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 * TODO: for dataplane learning and aging, do this:
140 * if refresh=0 and not a static mac, set refresh=1
142 counter_base[L2LEARN_ERROR_HIT] += 1;
145 else if (result0->raw == ~0)
148 /* 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;
164 BVT (clib_bihash_kv) kv;
165 /* It is ok to learn */
167 result0->raw = 0; /* clear all fields */
168 result0->fields.sw_if_index = sw_if_index0;
169 /* TODO: set timestamp in entry to clock for dataplane aging */
171 kv.value = result0->raw;
173 BV (clib_bihash_add_del) (msm->mac_table, &kv, 1 /* is_add */ );
175 cached_key->raw = ~0; /* invalidate the cache */
176 msm->global_learn_count++;
183 /* The entry was in the table, but with the wrong sw_if_index mapping (mac move) */
184 counter_base[L2LEARN_ERROR_MAC_MOVE] += 1;
186 if (result0->fields.static_mac)
189 * Don't overwrite a static mac
190 * TODO: Check violation policy. For now drop the packet
192 b0->error = node->errors[L2LEARN_ERROR_MAC_MOVE_VIOLATE];
193 *next0 = L2LEARN_NEXT_DROP;
199 * TODO: may want to rate limit mac moves
200 * TODO: check global/bridge domain/interface learn limits
202 BVT (clib_bihash_kv) kv;
204 result0->raw = 0; /* clear all fields */
205 result0->fields.sw_if_index = sw_if_index0;
208 kv.value = result0->raw;
210 cached_key->raw = ~0; /* invalidate the cache */
212 BV (clib_bihash_add_del) (msm->mac_table, &kv, 1 /* is_add */ );
216 if (result0->fields.filter)
218 /* drop packet because lookup matched a filter mac entry */
220 if (*next0 != L2LEARN_NEXT_DROP)
222 /* if we're not already dropping the packet, do it now */
223 b0->error = node->errors[L2LEARN_ERROR_FILTER_DROP];
224 *next0 = L2LEARN_NEXT_DROP;
234 l2learn_node_fn (vlib_main_t * vm,
235 vlib_node_runtime_t * node, vlib_frame_t * frame)
237 u32 n_left_from, *from, *to_next;
238 l2learn_next_t next_index;
239 l2learn_main_t *msm = &l2learn_main;
240 vlib_node_t *n = vlib_get_node (vm, l2learn_node.index);
241 u32 node_counter_base_index = n->error_heap_index;
242 vlib_error_main_t *em = &vm->error_main;
243 l2fib_entry_key_t cached_key;
244 l2fib_entry_result_t cached_result;
246 from = vlib_frame_vector_args (frame);
247 n_left_from = frame->n_vectors; /* number of packets to process */
248 next_index = node->cached_next_index;
250 /* Clear the one-entry cache in case mac table was updated */
252 cached_result.raw = ~0; /* warning be gone */
254 while (n_left_from > 0)
258 /* get space to enqueue frame to graph node "next_index" */
259 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
261 while (n_left_from >= 8 && n_left_to_next >= 4)
263 u32 bi0, bi1, bi2, bi3;
264 vlib_buffer_t *b0, *b1, *b2, *b3;
265 u32 next0, next1, next2, next3;
266 u32 sw_if_index0, sw_if_index1, sw_if_index2, sw_if_index3;
267 ethernet_header_t *h0, *h1, *h2, *h3;
268 l2fib_entry_key_t key0, key1, key2, key3;
269 l2fib_entry_result_t result0, result1, result2, result3;
270 u32 bucket0, bucket1, bucket2, bucket3;
272 /* Prefetch next iteration. */
274 vlib_buffer_t *p4, *p5, *p6, *p7;;
276 p4 = vlib_get_buffer (vm, from[4]);
277 p5 = vlib_get_buffer (vm, from[5]);
278 p6 = vlib_get_buffer (vm, from[6]);
279 p7 = vlib_get_buffer (vm, from[7]);
281 vlib_prefetch_buffer_header (p4, LOAD);
282 vlib_prefetch_buffer_header (p5, LOAD);
283 vlib_prefetch_buffer_header (p6, LOAD);
284 vlib_prefetch_buffer_header (p7, LOAD);
286 CLIB_PREFETCH (p4->data, CLIB_CACHE_LINE_BYTES, STORE);
287 CLIB_PREFETCH (p5->data, CLIB_CACHE_LINE_BYTES, STORE);
288 CLIB_PREFETCH (p6->data, CLIB_CACHE_LINE_BYTES, STORE);
289 CLIB_PREFETCH (p7->data, CLIB_CACHE_LINE_BYTES, STORE);
292 /* speculatively enqueue b0 and b1 to the current next frame */
293 /* bi is "buffer index", b is pointer to the buffer */
294 to_next[0] = bi0 = from[0];
295 to_next[1] = bi1 = from[1];
296 to_next[2] = bi2 = from[2];
297 to_next[3] = bi3 = from[3];
303 b0 = vlib_get_buffer (vm, bi0);
304 b1 = vlib_get_buffer (vm, bi1);
305 b2 = vlib_get_buffer (vm, bi2);
306 b3 = vlib_get_buffer (vm, bi3);
308 /* RX interface handles */
309 sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
310 sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
311 sw_if_index2 = vnet_buffer (b2)->sw_if_index[VLIB_RX];
312 sw_if_index3 = vnet_buffer (b3)->sw_if_index[VLIB_RX];
314 /* Process 4 x pkts */
316 h0 = vlib_buffer_get_current (b0);
317 h1 = vlib_buffer_get_current (b1);
318 h2 = vlib_buffer_get_current (b2);
319 h3 = vlib_buffer_get_current (b3);
321 if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)))
323 if (b0->flags & VLIB_BUFFER_IS_TRACED)
326 vlib_add_trace (vm, node, b0, sizeof (*t));
327 t->sw_if_index = sw_if_index0;
328 t->bd_index = vnet_buffer (b0)->l2.bd_index;
329 clib_memcpy (t->src, h0->src_address, 6);
330 clib_memcpy (t->dst, h0->dst_address, 6);
332 if (b1->flags & VLIB_BUFFER_IS_TRACED)
335 vlib_add_trace (vm, node, b1, sizeof (*t));
336 t->sw_if_index = sw_if_index1;
337 t->bd_index = vnet_buffer (b1)->l2.bd_index;
338 clib_memcpy (t->src, h1->src_address, 6);
339 clib_memcpy (t->dst, h1->dst_address, 6);
341 if (b2->flags & VLIB_BUFFER_IS_TRACED)
344 vlib_add_trace (vm, node, b2, sizeof (*t));
345 t->sw_if_index = sw_if_index2;
346 t->bd_index = vnet_buffer (b2)->l2.bd_index;
347 clib_memcpy (t->src, h2->src_address, 6);
348 clib_memcpy (t->dst, h2->dst_address, 6);
350 if (b3->flags & VLIB_BUFFER_IS_TRACED)
353 vlib_add_trace (vm, node, b3, sizeof (*t));
354 t->sw_if_index = sw_if_index3;
355 t->bd_index = vnet_buffer (b3)->l2.bd_index;
356 clib_memcpy (t->src, h3->src_address, 6);
357 clib_memcpy (t->dst, h3->dst_address, 6);
362 vlib_node_increment_counter (vm, l2learn_node.index,
363 L2LEARN_ERROR_L2LEARN, 4);
365 l2fib_lookup_4 (msm->mac_table, &cached_key, &cached_result,
370 vnet_buffer (b0)->l2.bd_index,
371 vnet_buffer (b1)->l2.bd_index,
372 vnet_buffer (b2)->l2.bd_index,
373 vnet_buffer (b3)->l2.bd_index,
374 &key0, &key1, &key2, &key3,
375 &bucket0, &bucket1, &bucket2, &bucket3,
376 &result0, &result1, &result2, &result3);
378 l2learn_process (node, msm, &em->counters[node_counter_base_index],
379 b0, sw_if_index0, &key0, &cached_key,
380 &bucket0, &result0, &next0);
382 l2learn_process (node, msm, &em->counters[node_counter_base_index],
383 b1, sw_if_index1, &key1, &cached_key,
384 &bucket1, &result1, &next1);
386 l2learn_process (node, msm, &em->counters[node_counter_base_index],
387 b2, sw_if_index2, &key2, &cached_key,
388 &bucket2, &result2, &next2);
390 l2learn_process (node, msm, &em->counters[node_counter_base_index],
391 b3, sw_if_index3, &key3, &cached_key,
392 &bucket3, &result3, &next3);
394 /* verify speculative enqueues, maybe switch current next frame */
395 /* if next0==next1==next_index then nothing special needs to be done */
396 vlib_validate_buffer_enqueue_x4 (vm, node, next_index,
397 to_next, n_left_to_next,
399 next0, next1, next2, next3);
402 while (n_left_from > 0 && n_left_to_next > 0)
408 ethernet_header_t *h0;
409 l2fib_entry_key_t key0;
410 l2fib_entry_result_t result0;
413 /* speculatively enqueue b0 to the current next frame */
421 b0 = vlib_get_buffer (vm, bi0);
423 sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
425 h0 = vlib_buffer_get_current (b0);
427 if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
428 && (b0->flags & VLIB_BUFFER_IS_TRACED)))
430 l2learn_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
431 t->sw_if_index = sw_if_index0;
432 t->bd_index = vnet_buffer (b0)->l2.bd_index;
433 clib_memcpy (t->src, h0->src_address, 6);
434 clib_memcpy (t->dst, h0->dst_address, 6);
438 vlib_node_increment_counter (vm, l2learn_node.index,
439 L2LEARN_ERROR_L2LEARN, 1);
442 l2fib_lookup_1 (msm->mac_table, &cached_key, &cached_result,
443 h0->src_address, vnet_buffer (b0)->l2.bd_index,
444 &key0, &bucket0, &result0);
446 l2learn_process (node, msm, &em->counters[node_counter_base_index],
447 b0, sw_if_index0, &key0, &cached_key,
448 &bucket0, &result0, &next0);
450 /* verify speculative enqueue, maybe switch current next frame */
451 vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
452 to_next, n_left_to_next,
456 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
459 return frame->n_vectors;
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 = L2FIB_NUM_BUCKETS * 16;
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")