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 >= 4 && n_left_to_next >= 2)
264 vlib_buffer_t *b0, *b1;
266 u32 sw_if_index0, sw_if_index1;
267 ethernet_header_t *h0, *h1;
268 l2fib_entry_key_t key0, key1;
269 l2fib_entry_result_t result0, result1;
270 u32 bucket0, bucket1;
272 /* Prefetch next iteration. */
274 vlib_buffer_t *p2, *p3;
276 p2 = vlib_get_buffer (vm, from[2]);
277 p3 = vlib_get_buffer (vm, from[3]);
279 vlib_prefetch_buffer_header (p2, LOAD);
280 vlib_prefetch_buffer_header (p3, LOAD);
282 CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE);
283 CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, STORE);
286 /* speculatively enqueue b0 and b1 to the current next frame */
287 /* bi is "buffer index", b is pointer to the buffer */
288 to_next[0] = bi0 = from[0];
289 to_next[1] = bi1 = from[1];
295 b0 = vlib_get_buffer (vm, bi0);
296 b1 = vlib_get_buffer (vm, bi1);
298 /* RX interface handles */
299 sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
300 sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
302 /* Process 2 x pkts */
304 h0 = vlib_buffer_get_current (b0);
305 h1 = vlib_buffer_get_current (b1);
307 if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)))
309 if (b0->flags & VLIB_BUFFER_IS_TRACED)
312 vlib_add_trace (vm, node, b0, sizeof (*t));
313 t->sw_if_index = sw_if_index0;
314 t->bd_index = vnet_buffer (b0)->l2.bd_index;
315 clib_memcpy (t->src, h0->src_address, 6);
316 clib_memcpy (t->dst, h0->dst_address, 6);
318 if (b1->flags & VLIB_BUFFER_IS_TRACED)
321 vlib_add_trace (vm, node, b1, sizeof (*t));
322 t->sw_if_index = sw_if_index1;
323 t->bd_index = vnet_buffer (b1)->l2.bd_index;
324 clib_memcpy (t->src, h1->src_address, 6);
325 clib_memcpy (t->dst, h1->dst_address, 6);
330 em->counters[node_counter_base_index + L2LEARN_ERROR_L2LEARN] += 2;
332 l2fib_lookup_2 (msm->mac_table, &cached_key, &cached_result,
335 vnet_buffer (b0)->l2.bd_index,
336 vnet_buffer (b1)->l2.bd_index,
338 &key1, &bucket0, &bucket1, &result0, &result1);
340 l2learn_process (node, msm, &em->counters[node_counter_base_index],
341 b0, sw_if_index0, &key0, &cached_key,
342 &bucket0, &result0, &next0);
344 l2learn_process (node, msm, &em->counters[node_counter_base_index],
345 b1, sw_if_index1, &key1, &cached_key,
346 &bucket1, &result1, &next1);
348 /* verify speculative enqueues, maybe switch current next frame */
349 /* if next0==next1==next_index then nothing special needs to be done */
350 vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
351 to_next, n_left_to_next,
352 bi0, bi1, next0, next1);
355 while (n_left_from > 0 && n_left_to_next > 0)
361 ethernet_header_t *h0;
362 l2fib_entry_key_t key0;
363 l2fib_entry_result_t result0;
366 /* speculatively enqueue b0 to the current next frame */
374 b0 = vlib_get_buffer (vm, bi0);
376 sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
378 h0 = vlib_buffer_get_current (b0);
380 if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
381 && (b0->flags & VLIB_BUFFER_IS_TRACED)))
383 l2learn_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
384 t->sw_if_index = sw_if_index0;
385 t->bd_index = vnet_buffer (b0)->l2.bd_index;
386 clib_memcpy (t->src, h0->src_address, 6);
387 clib_memcpy (t->dst, h0->dst_address, 6);
391 em->counters[node_counter_base_index + L2LEARN_ERROR_L2LEARN] += 1;
393 l2fib_lookup_1 (msm->mac_table, &cached_key, &cached_result,
394 h0->src_address, vnet_buffer (b0)->l2.bd_index,
395 &key0, &bucket0, &result0);
397 l2learn_process (node, msm, &em->counters[node_counter_base_index],
398 b0, sw_if_index0, &key0, &cached_key,
399 &bucket0, &result0, &next0);
401 /* verify speculative enqueue, maybe switch current next frame */
402 vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
403 to_next, n_left_to_next,
407 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
410 return frame->n_vectors;
415 VLIB_REGISTER_NODE (l2learn_node,static) = {
416 .function = l2learn_node_fn,
418 .vector_size = sizeof (u32),
419 .format_trace = format_l2learn_trace,
420 .type = VLIB_NODE_TYPE_INTERNAL,
422 .n_errors = ARRAY_LEN(l2learn_error_strings),
423 .error_strings = l2learn_error_strings,
425 .n_next_nodes = L2LEARN_N_NEXT,
427 /* edit / add dispositions here */
429 [L2LEARN_NEXT_DROP] = "error-drop",
430 [L2LEARN_NEXT_L2FWD] = "l2-fwd",
435 VLIB_NODE_FUNCTION_MULTIARCH (l2learn_node, l2learn_node_fn)
436 clib_error_t *l2learn_init (vlib_main_t * vm)
438 l2learn_main_t *mp = &l2learn_main;
441 mp->vnet_main = vnet_get_main ();
443 /* Initialize the feature next-node indexes */
444 feat_bitmap_init_next_nodes (vm,
447 l2input_get_feat_names (),
448 mp->feat_next_node_index);
450 /* init the hash table ptr */
451 mp->mac_table = get_mac_table ();
454 * Set the default number of dynamically learned macs to the number
457 mp->global_learn_limit = L2FIB_NUM_BUCKETS * 16;
462 VLIB_INIT_FUNCTION (l2learn_init);
466 * Set subinterface learn enable/disable.
468 * set interface l2 learn <interface> [disable]
470 static clib_error_t *
471 int_learn (vlib_main_t * vm,
472 unformat_input_t * input, vlib_cli_command_t * cmd)
474 vnet_main_t *vnm = vnet_get_main ();
475 clib_error_t *error = 0;
479 if (!unformat_user (input, unformat_vnet_sw_interface, vnm, &sw_if_index))
481 error = clib_error_return (0, "unknown interface `%U'",
482 format_unformat_error, input);
487 if (unformat (input, "disable"))
492 /* set the interface flag */
493 l2input_intf_bitmap_enable (sw_if_index, L2INPUT_FEAT_LEARN, enable);
500 * Layer 2 learning can be enabled and disabled on each
501 * interface and on each bridge-domain. Use this command to
502 * manage interfaces. It is enabled by default.
505 * Example of how to enable learning:
506 * @cliexcmd{set interface l2 learn GigabitEthernet0/8/0}
507 * Example of how to disable learning:
508 * @cliexcmd{set interface l2 learn GigabitEthernet0/8/0 disable}
511 VLIB_CLI_COMMAND (int_learn_cli, static) = {
512 .path = "set interface l2 learn",
513 .short_help = "set interface l2 learn <interface> [disable]",
514 .function = int_learn,
519 static clib_error_t *
520 l2learn_config (vlib_main_t * vm, unformat_input_t * input)
522 l2learn_main_t *mp = &l2learn_main;
524 while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
526 if (unformat (input, "limit %d", &mp->global_learn_limit))
530 return clib_error_return (0, "unknown input `%U'",
531 format_unformat_error, input);
537 VLIB_CONFIG_FUNCTION (l2learn_config, "l2learn");
541 * fd.io coding-style-patch-verification: ON
544 * eval: (c-set-style "gnu")