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/ethernet/ethernet.h>
23 #include <vnet/l2/l2_input.h>
24 #include <vnet/l2/feat_bitmap.h>
25 #include <vnet/l2/l2_fib.h>
26 #include <vnet/l2/l2_learn.h>
28 #include <vppinfra/error.h>
29 #include <vppinfra/hash.h>
31 #ifndef CLIB_MARCH_VARIANT
32 l2learn_main_t l2learn_main;
37 * @brief Ethernet Bridge Learning.
39 * Populate the mac table with entries mapping the packet's source mac + bridge
40 * domain ID to the input sw_if_index.
42 * Note that learning and forwarding are separate graph nodes. This means that
43 * for a set of packets, all learning is performed first, then all nodes are
44 * forwarded. The forwarding is done based on the end-state of the mac table,
45 * instead of the state after each packet. Thus the forwarding results could
46 * differ in certain cases (mac move tests), but this not expected to cause
47 * problems in real-world networks. It is much simpler to separate learning
48 * and forwarding into separate nodes.
61 /* packet trace format function */
63 format_l2learn_trace (u8 * s, va_list * args)
65 CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
66 CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
67 l2learn_trace_t *t = va_arg (*args, l2learn_trace_t *);
69 s = format (s, "l2-learn: sw_if_index %d dst %U src %U bd_index %d",
71 format_ethernet_address, t->dst,
72 format_ethernet_address, t->src, t->bd_index);
76 extern vlib_node_registration_t l2learn_node;
78 #define foreach_l2learn_error \
79 _(L2LEARN, "L2 learn packets") \
80 _(MISS, "L2 learn misses") \
81 _(MAC_MOVE, "L2 mac moves") \
82 _(MAC_MOVE_VIOLATE, "L2 mac move violations") \
83 _(LIMIT, "L2 not learned due to limit") \
84 _(HIT_UPDATE, "L2 learn hit updates") \
85 _(FILTER_DROP, "L2 filter mac drops")
89 #define _(sym,str) L2LEARN_ERROR_##sym,
95 static char *l2learn_error_strings[] = {
96 #define _(sym,string) string,
109 /** Perform learning on one packet based on the mac table lookup result. */
111 static_always_inline void
112 l2learn_process (vlib_node_runtime_t * node,
113 l2learn_main_t * msm,
117 l2fib_entry_key_t * key0,
118 l2fib_entry_key_t * cached_key,
120 l2fib_entry_result_t * result0, u16 * next0, u8 timestamp)
122 /* Set up the default next node (typically L2FWD) */
123 *next0 = vnet_l2_feature_next (b0, msm->feat_next_node_index,
126 /* Check mac table lookup result */
127 if (PREDICT_TRUE (result0->fields.sw_if_index == sw_if_index0))
129 /* Entry in L2FIB with matching sw_if_index matched - normal fast path */
130 u32 dtime = timestamp - result0->fields.timestamp;
131 u32 dsn = result0->fields.sn.as_u16 - vnet_buffer (b0)->l2.l2fib_sn;
132 u32 check = (dtime && vnet_buffer (b0)->l2.bd_age) || dsn;
134 if (PREDICT_TRUE (check == 0))
135 return; /* MAC entry up to date */
136 if (l2fib_entry_result_is_set_AGE_NOT (result0))
137 return; /* Static MAC always age_not */
138 if (msm->global_learn_count > msm->global_learn_limit)
139 return; /* Above learn limit - do not update */
141 /* Limit updates per l2-learn node call to avoid prolonged update burst
142 * as dtime advance over 1 minute mark, unless more than 1 min behind
144 if ((*count > 2) && (dtime == 1) && (dsn == 0))
147 counter_base[L2LEARN_ERROR_HIT_UPDATE] += 1;
150 else if (result0->raw == ~0)
152 /* Entry not in L2FIB - add it */
153 counter_base[L2LEARN_ERROR_MISS] += 1;
155 if (msm->global_learn_count >= msm->global_learn_limit)
158 * Global limit reached. Do not learn the mac but forward the packet.
159 * In the future, limits could also be per-interface or bridge-domain.
161 counter_base[L2LEARN_ERROR_LIMIT] += 1;
165 /* Do not learn if mac is 0 */
166 l2fib_entry_key_t key = *key0;
167 key.fields.bd_index = 0;
171 /* It is ok to learn */
172 msm->global_learn_count++;
173 result0->raw = 0; /* clear all fields */
174 result0->fields.sw_if_index = sw_if_index0;
175 if (msm->client_pid != 0)
176 l2fib_entry_result_set_LRN_EVT (result0);
178 l2fib_entry_result_clear_LRN_EVT (result0);
182 /* Entry in L2FIB with different sw_if_index - mac move or filter */
183 if (l2fib_entry_result_is_set_FILTER (result0))
185 ASSERT (result0->fields.sw_if_index == ~0);
186 /* drop packet because lookup matched a filter mac entry */
187 b0->error = node->errors[L2LEARN_ERROR_FILTER_DROP];
188 *next0 = L2LEARN_NEXT_DROP;
192 if (l2fib_entry_result_is_set_STATIC (result0))
195 * Don't overwrite a static mac
196 * TODO: Check violation policy. For now drop the packet
198 b0->error = node->errors[L2LEARN_ERROR_MAC_MOVE_VIOLATE];
199 *next0 = L2LEARN_NEXT_DROP;
204 * TODO: may want to rate limit mac moves
205 * TODO: check global/bridge domain/interface learn limits
207 result0->fields.sw_if_index = sw_if_index0;
208 if (l2fib_entry_result_is_set_AGE_NOT (result0))
210 /* The mac was provisioned */
211 msm->global_learn_count++;
212 l2fib_entry_result_clear_AGE_NOT (result0);
214 if (msm->client_pid != 0)
215 l2fib_entry_result_set_bits (result0,
216 (L2FIB_ENTRY_RESULT_FLAG_LRN_EVT |
217 L2FIB_ENTRY_RESULT_FLAG_LRN_MOV));
219 l2fib_entry_result_clear_bits (result0,
220 (L2FIB_ENTRY_RESULT_FLAG_LRN_EVT |
221 L2FIB_ENTRY_RESULT_FLAG_LRN_MOV));
222 counter_base[L2LEARN_ERROR_MAC_MOVE] += 1;
225 /* Update the entry */
226 result0->fields.timestamp = timestamp;
227 result0->fields.sn.as_u16 = vnet_buffer (b0)->l2.l2fib_sn;
229 BVT (clib_bihash_kv) kv;
231 kv.value = result0->raw;
232 BV (clib_bihash_add_del) (msm->mac_table, &kv, 1 /* is_add */ );
234 /* Invalidate the cache */
235 cached_key->raw = ~0;
239 static_always_inline uword
240 l2learn_node_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
241 vlib_frame_t * frame, int do_trace)
244 l2learn_main_t *msm = &l2learn_main;
245 vlib_node_t *n = vlib_get_node (vm, l2learn_node.index);
246 u32 node_counter_base_index = n->error_heap_index;
247 vlib_error_main_t *em = &vm->error_main;
248 l2fib_entry_key_t cached_key;
249 l2fib_entry_result_t cached_result;
250 u8 timestamp = (u8) (vlib_time_now (vm) / 60);
252 vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b;
253 u16 nexts[VLIB_FRAME_SIZE], *next;
255 from = vlib_frame_vector_args (frame);
256 n_left = frame->n_vectors; /* number of packets to process */
257 vlib_get_buffers (vm, from, bufs, n_left);
261 /* Clear the one-entry cache in case mac table was updated */
263 cached_result.raw = ~0; /* warning be gone */
267 u32 sw_if_index0, sw_if_index1, sw_if_index2, sw_if_index3;
268 const ethernet_header_t *h0, *h1, *h2, *h3;
269 l2fib_entry_key_t key0, key1, key2, key3;
270 l2fib_entry_result_t result0, result1, result2, result3;
272 /* Prefetch next iteration. */
274 /* buffer header is read and written, so use LOAD
276 vlib_prefetch_buffer_header (b[4], LOAD);
277 vlib_prefetch_buffer_header (b[5], LOAD);
278 vlib_prefetch_buffer_header (b[6], LOAD);
279 vlib_prefetch_buffer_header (b[7], LOAD);
281 CLIB_PREFETCH (b[4]->data, CLIB_CACHE_LINE_BYTES, LOAD);
282 CLIB_PREFETCH (b[5]->data, CLIB_CACHE_LINE_BYTES, LOAD);
283 CLIB_PREFETCH (b[6]->data, CLIB_CACHE_LINE_BYTES, LOAD);
284 CLIB_PREFETCH (b[7]->data, CLIB_CACHE_LINE_BYTES, LOAD);
287 /* RX interface handles */
288 sw_if_index0 = vnet_buffer (b[0])->sw_if_index[VLIB_RX];
289 sw_if_index1 = vnet_buffer (b[1])->sw_if_index[VLIB_RX];
290 sw_if_index2 = vnet_buffer (b[2])->sw_if_index[VLIB_RX];
291 sw_if_index3 = vnet_buffer (b[3])->sw_if_index[VLIB_RX];
293 /* Process 4 x pkts */
295 h0 = vlib_buffer_get_current (b[0]);
296 h1 = vlib_buffer_get_current (b[1]);
297 h2 = vlib_buffer_get_current (b[2]);
298 h3 = vlib_buffer_get_current (b[3]);
302 if (b[0]->flags & VLIB_BUFFER_IS_TRACED)
305 vlib_add_trace (vm, node, b[0], sizeof (*t));
306 t->sw_if_index = sw_if_index0;
307 t->bd_index = vnet_buffer (b[0])->l2.bd_index;
308 clib_memcpy_fast (t->src, h0->src_address, 6);
309 clib_memcpy_fast (t->dst, h0->dst_address, 6);
311 if (b[1]->flags & VLIB_BUFFER_IS_TRACED)
314 vlib_add_trace (vm, node, b[1], sizeof (*t));
315 t->sw_if_index = sw_if_index1;
316 t->bd_index = vnet_buffer (b[1])->l2.bd_index;
317 clib_memcpy_fast (t->src, h1->src_address, 6);
318 clib_memcpy_fast (t->dst, h1->dst_address, 6);
320 if (b[2]->flags & VLIB_BUFFER_IS_TRACED)
323 vlib_add_trace (vm, node, b[2], sizeof (*t));
324 t->sw_if_index = sw_if_index2;
325 t->bd_index = vnet_buffer (b[2])->l2.bd_index;
326 clib_memcpy_fast (t->src, h2->src_address, 6);
327 clib_memcpy_fast (t->dst, h2->dst_address, 6);
329 if (b[3]->flags & VLIB_BUFFER_IS_TRACED)
332 vlib_add_trace (vm, node, b[3], sizeof (*t));
333 t->sw_if_index = sw_if_index3;
334 t->bd_index = vnet_buffer (b[3])->l2.bd_index;
335 clib_memcpy_fast (t->src, h3->src_address, 6);
336 clib_memcpy_fast (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 (b[0])->l2.bd_index,
350 vnet_buffer (b[1])->l2.bd_index,
351 vnet_buffer (b[2])->l2.bd_index,
352 vnet_buffer (b[3])->l2.bd_index,
353 &key0, &key1, &key2, &key3,
354 &result0, &result1, &result2, &result3);
356 l2learn_process (node, msm, &em->counters[node_counter_base_index],
357 b[0], sw_if_index0, &key0, &cached_key,
358 &count, &result0, next, timestamp);
360 l2learn_process (node, msm, &em->counters[node_counter_base_index],
361 b[1], sw_if_index1, &key1, &cached_key,
362 &count, &result1, next + 1, timestamp);
364 l2learn_process (node, msm, &em->counters[node_counter_base_index],
365 b[2], sw_if_index2, &key2, &cached_key,
366 &count, &result2, next + 2, timestamp);
368 l2learn_process (node, msm, &em->counters[node_counter_base_index],
369 b[3], sw_if_index3, &key3, &cached_key,
370 &count, &result3, next + 3, timestamp);
380 ethernet_header_t *h0;
381 l2fib_entry_key_t key0;
382 l2fib_entry_result_t result0;
384 sw_if_index0 = vnet_buffer (b[0])->sw_if_index[VLIB_RX];
386 h0 = vlib_buffer_get_current (b[0]);
388 if (do_trace && PREDICT_FALSE (b[0]->flags & VLIB_BUFFER_IS_TRACED))
390 l2learn_trace_t *t = vlib_add_trace (vm, node, b[0], sizeof (*t));
391 t->sw_if_index = sw_if_index0;
392 t->bd_index = vnet_buffer (b[0])->l2.bd_index;
393 clib_memcpy_fast (t->src, h0->src_address, 6);
394 clib_memcpy_fast (t->dst, h0->dst_address, 6);
398 vlib_node_increment_counter (vm, l2learn_node.index,
399 L2LEARN_ERROR_L2LEARN, 1);
402 l2fib_lookup_1 (msm->mac_table, &cached_key, &cached_result,
403 h0->src_address, vnet_buffer (b[0])->l2.bd_index,
406 l2learn_process (node, msm, &em->counters[node_counter_base_index],
407 b[0], sw_if_index0, &key0, &cached_key,
408 &count, &result0, next, timestamp);
415 vlib_buffer_enqueue_to_next (vm, node, from, nexts, frame->n_vectors);
417 return frame->n_vectors;
420 VLIB_NODE_FN (l2learn_node) (vlib_main_t * vm,
421 vlib_node_runtime_t * node, vlib_frame_t * frame)
423 if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)))
424 return l2learn_node_inline (vm, node, frame, 1 /* do_trace */ );
425 return l2learn_node_inline (vm, node, frame, 0 /* do_trace */ );
429 VLIB_REGISTER_NODE (l2learn_node) = {
431 .vector_size = sizeof (u32),
432 .format_trace = format_l2learn_trace,
433 .type = VLIB_NODE_TYPE_INTERNAL,
435 .n_errors = ARRAY_LEN(l2learn_error_strings),
436 .error_strings = l2learn_error_strings,
438 .n_next_nodes = L2LEARN_N_NEXT,
440 /* edit / add dispositions here */
442 [L2LEARN_NEXT_DROP] = "error-drop",
443 [L2LEARN_NEXT_L2FWD] = "l2-fwd",
448 #ifndef CLIB_MARCH_VARIANT
450 l2learn_init (vlib_main_t * vm)
452 l2learn_main_t *mp = &l2learn_main;
455 mp->vnet_main = vnet_get_main ();
457 /* Initialize the feature next-node indexes */
458 feat_bitmap_init_next_nodes (vm,
461 l2input_get_feat_names (),
462 mp->feat_next_node_index);
464 /* init the hash table ptr */
465 mp->mac_table = get_mac_table ();
468 * Set the default number of dynamically learned macs to the number
471 mp->global_learn_limit = L2LEARN_DEFAULT_LIMIT;
476 VLIB_INIT_FUNCTION (l2learn_init);
480 * Set subinterface learn enable/disable.
482 * set interface l2 learn <interface> [disable]
484 static clib_error_t *
485 int_learn (vlib_main_t * vm,
486 unformat_input_t * input, vlib_cli_command_t * cmd)
488 vnet_main_t *vnm = vnet_get_main ();
489 clib_error_t *error = 0;
493 if (!unformat_user (input, unformat_vnet_sw_interface, vnm, &sw_if_index))
495 error = clib_error_return (0, "unknown interface `%U'",
496 format_unformat_error, input);
501 if (unformat (input, "disable"))
506 /* set the interface flag */
507 l2input_intf_bitmap_enable (sw_if_index, L2INPUT_FEAT_LEARN, enable);
514 * Layer 2 learning can be enabled and disabled on each
515 * interface and on each bridge-domain. Use this command to
516 * manage interfaces. It is enabled by default.
519 * Example of how to enable learning:
520 * @cliexcmd{set interface l2 learn GigabitEthernet0/8/0}
521 * Example of how to disable learning:
522 * @cliexcmd{set interface l2 learn GigabitEthernet0/8/0 disable}
525 VLIB_CLI_COMMAND (int_learn_cli, static) = {
526 .path = "set interface l2 learn",
527 .short_help = "set interface l2 learn <interface> [disable]",
528 .function = int_learn,
533 static clib_error_t *
534 l2learn_config (vlib_main_t * vm, unformat_input_t * input)
536 l2learn_main_t *mp = &l2learn_main;
538 while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
540 if (unformat (input, "limit %d", &mp->global_learn_limit))
544 return clib_error_return (0, "unknown input `%U'",
545 format_unformat_error, input);
551 VLIB_CONFIG_FUNCTION (l2learn_config, "l2learn");
557 * fd.io coding-style-patch-verification: ON
560 * eval: (c-set-style "gnu")