2 * l2_flood.c : layer 2 flooding
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>
23 #include <vnet/l2/l2_input.h>
24 #include <vnet/l2/feat_bitmap.h>
25 #include <vnet/l2/l2_bvi.h>
26 #include <vnet/replication.h>
27 #include <vnet/l2/l2_fib.h>
29 #include <vppinfra/error.h>
30 #include <vppinfra/hash.h>
35 * @brief Ethernet Flooding.
37 * Flooding uses the packet replication infrastructure to send a copy of the
38 * packet to each member interface. Logically the replication infrastructure
39 * expects two graph nodes: a prep node that initiates replication and sends the
40 * packet to the first destination, and a recycle node that is passed the packet
41 * after it has been transmitted.
43 * To decrease the amount of code, l2 flooding implements both functions in
44 * the same graph node. This node can tell if is it being called as the "prep"
45 * or "recycle" using replication_is_recycled().
52 /* Next nodes for each feature */
53 u32 feat_next_node_index[32];
55 /* next node index for the L3 input node of each ethertype */
56 next_by_ethertype_t l3_next;
58 /* convenience variables */
59 vlib_main_t *vlib_main;
60 vnet_main_t *vnet_main;
72 /* packet trace format function */
74 format_l2flood_trace (u8 * s, va_list * args)
76 CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
77 CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
78 l2flood_trace_t *t = va_arg (*args, l2flood_trace_t *);
80 s = format (s, "l2-flood: sw_if_index %d dst %U src %U bd_index %d",
82 format_ethernet_address, t->dst,
83 format_ethernet_address, t->src, t->bd_index);
87 l2flood_main_t l2flood_main;
89 static vlib_node_registration_t l2flood_node;
91 #define foreach_l2flood_error \
92 _(L2FLOOD, "L2 flood packets") \
93 _(REPL_FAIL, "L2 replication failures") \
94 _(NO_MEMBERS, "L2 replication complete") \
95 _(BVI_BAD_MAC, "BVI L3 mac mismatch") \
96 _(BVI_ETHERTYPE, "BVI packet with unhandled ethertype")
100 #define _(sym,str) L2FLOOD_ERROR_##sym,
101 foreach_l2flood_error
106 static char *l2flood_error_strings[] = {
107 #define _(sym,string) string,
108 foreach_l2flood_error
114 L2FLOOD_NEXT_L2_OUTPUT,
120 * Perform flooding on one packet
122 * Due to the way BVI processing can modify the packet, the BVI interface
123 * (if present) must be processed last in the replication. The member vector
124 * is arranged so that the BVI interface is always the first element.
125 * Flooding walks the vector in reverse.
127 * BVI processing causes the packet to go to L3 processing. This strips the
128 * L2 header, which is fine because the replication infrastructure restores
129 * it. However L3 processing can trigger larger changes to the packet. For
130 * example, an ARP request could be turned into an ARP reply, an ICMP request
131 * could be turned into an ICMP reply. If BVI processing is not performed
132 * last, the modified packet would be replicated to the remaining members.
135 static_always_inline void
136 l2flood_process (vlib_main_t * vm,
137 vlib_node_runtime_t * node,
138 l2flood_main_t * msm,
142 l2fib_entry_key_t * key0,
143 u32 * bucket0, l2fib_entry_result_t * result0, u32 * next0)
146 l2_bridge_domain_t *bd_config;
147 l2_flood_member_t *members;
148 i32 current_member; /* signed */
149 replication_context_t *ctx;
150 u8 in_shg = vnet_buffer (b0)->l2.shg;
152 if (!replication_is_recycled (b0))
155 /* Do flood "prep node" processing */
157 /* Get config for the bridge domain interface */
158 bd_index0 = vnet_buffer (b0)->l2.bd_index;
159 bd_config = vec_elt_at_index (l2input_main.bd_configs, bd_index0);
160 members = bd_config->members;
162 /* Find first member that passes the reflection and SHG checks */
163 current_member = bd_config->flood_count - 1;
164 while ((current_member >= 0) &&
165 ((members[current_member].sw_if_index == *sw_if_index0) ||
166 (in_shg && members[current_member].shg == in_shg)))
171 if (current_member < 0)
173 /* No members to flood to */
174 *next0 = L2FLOOD_NEXT_DROP;
175 b0->error = node->errors[L2FLOOD_ERROR_NO_MEMBERS];
179 if ((current_member > 0) &&
180 ((current_member > 1) ||
181 ((members[0].sw_if_index != *sw_if_index0) &&
182 (!in_shg || members[0].shg != in_shg))))
184 /* If more than one member then initiate replication */
186 replication_prep (vm, b0, l2flood_node.index, 1 /* l2_packet */ );
187 ctx->feature_replicas = (uword) members;
188 ctx->feature_counter = current_member;
194 vnet_buffer_opaque_t *vnet_buff_op;
196 /* Do flood "recycle node" processing */
198 if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_REPL_FAIL))
200 (void) replication_recycle (vm, b0, 1 /* is_last */ );
201 *next0 = L2FLOOD_NEXT_DROP;
202 b0->error = node->errors[L2FLOOD_ERROR_REPL_FAIL];
206 ctx = replication_get_ctx (b0);
207 replication_clear_recycled (b0);
209 members = (l2_flood_member_t *) (intptr_t) ctx->feature_replicas;
210 current_member = (i32) ctx->feature_counter - 1;
212 /* Need to update input index from saved packet context */
213 vnet_buff_op = (vnet_buffer_opaque_t *) ctx->vnet_buffer;
214 *sw_if_index0 = vnet_buff_op->sw_if_index[VLIB_RX];
216 /* Find next member that passes the reflection and SHG check */
217 while ((current_member >= 0) &&
218 ((members[current_member].sw_if_index == *sw_if_index0) ||
219 (in_shg && members[current_member].shg == in_shg)))
224 if (current_member < 0)
227 * No more members to flood to.
228 * Terminate replication and drop packet.
231 replication_recycle (vm, b0, 1 /* is_last */ );
233 *next0 = L2FLOOD_NEXT_DROP;
234 /* Ideally we woudn't bump a counter here, just silently complete */
235 b0->error = node->errors[L2FLOOD_ERROR_NO_MEMBERS];
239 /* Restore packet and context and continue replication */
240 ctx->feature_counter = current_member;
241 replication_recycle (vm, b0, ((current_member == 0) || /*is_last */
242 ((current_member == 1) &&
243 ((members[0].sw_if_index ==
244 *sw_if_index0) || (in_shg
249 /* Forward packet to the current member */
250 if (PREDICT_FALSE (members[current_member].flags & L2_FLOOD_MEMBER_BVI))
252 /* Do BVI processing */
257 members[current_member].sw_if_index,
258 &msm->l3_next, next0);
260 if (PREDICT_FALSE (rc))
262 if (rc == TO_BVI_ERR_BAD_MAC)
264 b0->error = node->errors[L2FLOOD_ERROR_BVI_BAD_MAC];
265 *next0 = L2FLOOD_NEXT_DROP;
267 else if (rc == TO_BVI_ERR_ETHERTYPE)
269 b0->error = node->errors[L2FLOOD_ERROR_BVI_ETHERTYPE];
270 *next0 = L2FLOOD_NEXT_DROP;
276 /* Do normal L2 forwarding */
277 vnet_buffer (b0)->sw_if_index[VLIB_TX] =
278 members[current_member].sw_if_index;
279 *next0 = L2FLOOD_NEXT_L2_OUTPUT;
287 l2flood_node_fn (vlib_main_t * vm,
288 vlib_node_runtime_t * node, vlib_frame_t * frame)
290 u32 n_left_from, *from, *to_next;
291 l2flood_next_t next_index;
292 l2flood_main_t *msm = &l2flood_main;
293 vlib_node_t *n = vlib_get_node (vm, l2flood_node.index);
294 u32 node_counter_base_index = n->error_heap_index;
295 vlib_error_main_t *em = &vm->error_main;
297 from = vlib_frame_vector_args (frame);
298 n_left_from = frame->n_vectors; /* number of packets to process */
299 next_index = node->cached_next_index;
301 while (n_left_from > 0)
305 /* get space to enqueue frame to graph node "next_index" */
306 vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
308 while (n_left_from >= 6 && n_left_to_next >= 2)
311 vlib_buffer_t *b0, *b1;
313 u32 sw_if_index0, sw_if_index1;
314 l2fib_entry_key_t key0, key1;
315 l2fib_entry_result_t result0, result1;
316 u32 bucket0, bucket1;
318 /* Prefetch next iteration. */
320 vlib_buffer_t *p2, *p3, *p4, *p5;
322 p2 = vlib_get_buffer (vm, from[2]);
323 p3 = vlib_get_buffer (vm, from[3]);
324 p4 = vlib_get_buffer (vm, from[4]);
325 p5 = vlib_get_buffer (vm, from[5]);
327 /* Prefetch the buffer header for the N+2 loop iteration */
328 vlib_prefetch_buffer_header (p4, LOAD);
329 vlib_prefetch_buffer_header (p5, LOAD);
331 /* Prefetch the replication context for the N+1 loop iteration */
332 /* This depends on the buffer header above */
333 replication_prefetch_ctx (p2);
334 replication_prefetch_ctx (p3);
336 /* Prefetch the packet for the N+1 loop iteration */
337 CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE);
338 CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, STORE);
341 /* speculatively enqueue b0 and b1 to the current next frame */
342 /* bi is "buffer index", b is pointer to the buffer */
343 to_next[0] = bi0 = from[0];
344 to_next[1] = bi1 = from[1];
350 b0 = vlib_get_buffer (vm, bi0);
351 b1 = vlib_get_buffer (vm, bi1);
353 /* RX interface handles */
354 sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
355 sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
358 em->counters[node_counter_base_index + L2FLOOD_ERROR_L2FLOOD] += 2;
360 l2flood_process (vm, node, msm,
361 &em->counters[node_counter_base_index], b0,
362 &sw_if_index0, &key0, &bucket0, &result0, &next0);
364 l2flood_process (vm, node, msm,
365 &em->counters[node_counter_base_index], b1,
366 &sw_if_index1, &key1, &bucket1, &result1, &next1);
368 if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)))
370 if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
373 vlib_add_trace (vm, node, b0, sizeof (*t));
374 ethernet_header_t *h0 = vlib_buffer_get_current (b0);
375 t->sw_if_index = sw_if_index0;
376 t->bd_index = vnet_buffer (b0)->l2.bd_index;
377 clib_memcpy (t->src, h0->src_address, 6);
378 clib_memcpy (t->dst, h0->dst_address, 6);
380 if (PREDICT_FALSE (b1->flags & VLIB_BUFFER_IS_TRACED))
383 vlib_add_trace (vm, node, b1, sizeof (*t));
384 ethernet_header_t *h1 = vlib_buffer_get_current (b1);
385 t->sw_if_index = sw_if_index1;
386 t->bd_index = vnet_buffer (b1)->l2.bd_index;
387 clib_memcpy (t->src, h1->src_address, 6);
388 clib_memcpy (t->dst, h1->dst_address, 6);
392 /* verify speculative enqueues, maybe switch current next frame */
393 /* if next0==next1==next_index then nothing special needs to be done */
394 vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
395 to_next, n_left_to_next,
396 bi0, bi1, next0, next1);
399 while (n_left_from > 0 && n_left_to_next > 0)
405 l2fib_entry_key_t key0;
406 l2fib_entry_result_t result0;
409 /* speculatively enqueue b0 to the current next frame */
417 b0 = vlib_get_buffer (vm, bi0);
419 sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
422 em->counters[node_counter_base_index + L2FLOOD_ERROR_L2FLOOD] += 1;
424 l2flood_process (vm, node, msm,
425 &em->counters[node_counter_base_index], b0,
426 &sw_if_index0, &key0, &bucket0, &result0, &next0);
428 if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE) &&
429 (b0->flags & VLIB_BUFFER_IS_TRACED)))
431 l2flood_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
432 ethernet_header_t *h0 = vlib_buffer_get_current (b0);
433 t->sw_if_index = sw_if_index0;
434 t->bd_index = vnet_buffer (b0)->l2.bd_index;
435 clib_memcpy (t->src, h0->src_address, 6);
436 clib_memcpy (t->dst, h0->dst_address, 6);
439 /* verify speculative enqueue, maybe switch current next frame */
440 vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
441 to_next, n_left_to_next,
445 vlib_put_next_frame (vm, node, next_index, n_left_to_next);
448 return frame->n_vectors;
453 VLIB_REGISTER_NODE (l2flood_node,static) = {
454 .function = l2flood_node_fn,
456 .vector_size = sizeof (u32),
457 .format_trace = format_l2flood_trace,
458 .type = VLIB_NODE_TYPE_INTERNAL,
460 .n_errors = ARRAY_LEN(l2flood_error_strings),
461 .error_strings = l2flood_error_strings,
463 .n_next_nodes = L2FLOOD_N_NEXT,
465 /* edit / add dispositions here */
467 [L2FLOOD_NEXT_L2_OUTPUT] = "l2-output",
468 [L2FLOOD_NEXT_DROP] = "error-drop",
473 VLIB_NODE_FUNCTION_MULTIARCH (l2flood_node, l2flood_node_fn)
474 clib_error_t *l2flood_init (vlib_main_t * vm)
476 l2flood_main_t *mp = &l2flood_main;
479 mp->vnet_main = vnet_get_main ();
481 /* Initialize the feature next-node indexes */
482 feat_bitmap_init_next_nodes (vm,
485 l2input_get_feat_names (),
486 mp->feat_next_node_index);
491 VLIB_INIT_FUNCTION (l2flood_init);
495 /** Add the L3 input node for this ethertype to the next nodes structure. */
497 l2flood_register_input_type (vlib_main_t * vm,
498 ethernet_type_t type, u32 node_index)
500 l2flood_main_t *mp = &l2flood_main;
503 next_index = vlib_node_add_next (vm, l2flood_node.index, node_index);
505 next_by_ethertype_register (&mp->l3_next, type, next_index);
510 * Set subinterface flood enable/disable.
512 * set interface l2 flood <interface> [disable]
514 static clib_error_t *
515 int_flood (vlib_main_t * vm,
516 unformat_input_t * input, vlib_cli_command_t * cmd)
518 vnet_main_t *vnm = vnet_get_main ();
519 clib_error_t *error = 0;
523 if (!unformat_user (input, unformat_vnet_sw_interface, vnm, &sw_if_index))
525 error = clib_error_return (0, "unknown interface `%U'",
526 format_unformat_error, input);
531 if (unformat (input, "disable"))
536 /* set the interface flag */
537 l2input_intf_bitmap_enable (sw_if_index, L2INPUT_FEAT_FLOOD, enable);
544 * Layer 2 flooding can be enabled and disabled on each
545 * interface and on each bridge-domain. Use this command to
546 * manage interfaces. It is enabled by default.
549 * Example of how to enable flooding:
550 * @cliexcmd{set interface l2 flood GigabitEthernet0/8/0}
551 * Example of how to disable flooding:
552 * @cliexcmd{set interface l2 flood GigabitEthernet0/8/0 disable}
555 VLIB_CLI_COMMAND (int_flood_cli, static) = {
556 .path = "set interface l2 flood",
557 .short_help = "set interface l2 flood <interface> [disable]",
558 .function = int_flood,
563 * fd.io coding-style-patch-verification: ON
566 * eval: (c-set-style "gnu")