/* * l2_learn.c : layer 2 learning using l2fib * * Copyright (c) 2013 Cisco and/or its affiliates. * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at: * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include #include #include #include #include #include #include #include #include #include #ifndef CLIB_MARCH_VARIANT l2learn_main_t l2learn_main; #endif /** * @file * @brief Ethernet Bridge Learning. * * Populate the mac table with entries mapping the packet's source mac + bridge * domain ID to the input sw_if_index. * * Note that learning and forwarding are separate graph nodes. This means that * for a set of packets, all learning is performed first, then all nodes are * forwarded. The forwarding is done based on the end-state of the mac table, * instead of the state after each packet. Thus the forwarding results could * differ in certain cases (mac move tests), but this not expected to cause * problems in real-world networks. It is much simpler to separate learning * and forwarding into separate nodes. */ typedef struct { u8 src[6]; u8 dst[6]; u32 sw_if_index; u16 bd_index; } l2learn_trace_t; /* packet trace format function */ static u8 * format_l2learn_trace (u8 * s, va_list * args) { CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *); CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *); l2learn_trace_t *t = va_arg (*args, l2learn_trace_t *); s = format (s, "l2-learn: sw_if_index %d dst %U src %U bd_index %d", t->sw_if_index, format_ethernet_address, t->dst, format_ethernet_address, t->src, t->bd_index); return s; } extern vlib_node_registration_t l2learn_node; #define foreach_l2learn_error \ _(L2LEARN, "L2 learn packets") \ _(MISS, "L2 learn misses") \ _(MAC_MOVE, "L2 mac moves") \ _(MAC_MOVE_VIOLATE, "L2 mac move violations") \ _(LIMIT, "L2 not learned due to limit") \ _(HIT_UPDATE, "L2 learn hit updates") \ _(FILTER_DROP, "L2 filter mac drops") typedef enum { #define _(sym,str) L2LEARN_ERROR_##sym, foreach_l2learn_error #undef _ L2LEARN_N_ERROR, } l2learn_error_t; static char *l2learn_error_strings[] = { #define _(sym,string) string, foreach_l2learn_error #undef _ }; typedef enum { L2LEARN_NEXT_L2FWD, L2LEARN_NEXT_DROP, L2LEARN_N_NEXT, } l2learn_next_t; /** Perform learning on one packet based on the mac table lookup result. */ static_always_inline void l2learn_process (vlib_node_runtime_t * node, l2learn_main_t * msm, u64 * counter_base, vlib_buffer_t * b0, u32 sw_if_index0, l2fib_entry_key_t * key0, l2fib_entry_key_t * cached_key, u32 * count, l2fib_entry_result_t * result0, u16 * next0, u8 timestamp) { l2_bridge_domain_t *bd_config = vec_elt_at_index (l2input_main.bd_configs, vnet_buffer (b0)->l2.bd_index); /* Set up the default next node (typically L2FWD) */ *next0 = vnet_l2_feature_next (b0, msm->feat_next_node_index, L2INPUT_FEAT_LEARN); /* Check mac table lookup result */ if (PREDICT_TRUE (result0->fields.sw_if_index == sw_if_index0)) { /* Entry in L2FIB with matching sw_if_index matched - normal fast path */ u32 dtime = timestamp - result0->fields.timestamp; u32 dsn = (result0->fields.sn - vnet_buffer (b0)->l2.l2fib_sn); u32 check = (dtime && vnet_buffer (b0)->l2.bd_age) || dsn; if (PREDICT_TRUE (check == 0)) return; /* MAC entry up to date */ if (l2fib_entry_result_is_set_AGE_NOT (result0)) return; /* Static MAC always age_not */ if (msm->global_learn_count > msm->global_learn_limit) return; /* Above learn limit - do not update */ if (bd_config->learn_count > bd_config->learn_limit) return; /* Above bridge domain learn limit - do not update */ /* Limit updates per l2-learn node call to avoid prolonged update burst * as dtime advance over 1 minute mark, unless more than 1 min behind * or SN obsolete */ if ((*count > 2) && (dtime == 1) && (dsn == 0)) return; counter_base[L2LEARN_ERROR_HIT_UPDATE] += 1; *count += 1; } else if (result0->raw == ~0) { /* Entry not in L2FIB - add it */ counter_base[L2LEARN_ERROR_MISS] += 1; if ((msm->global_learn_count >= msm->global_learn_limit) || (bd_config->learn_count >= bd_config->learn_limit)) { /* * Global limit reached. Do not learn the mac but forward the packet. * In the future, limits could also be per-interface or bridge-domain. */ counter_base[L2LEARN_ERROR_LIMIT] += 1; return; } /* Do not learn if mac is 0 */ l2fib_entry_key_t key = *key0; key.fields.bd_index = 0; if (key.raw == 0) return; /* It is ok to learn */ /* learn_count variable may have little inaccuracy because they are not * incremented/decremented with atomic operations */ /* l2fib_scan is call every 2sec fixing potential inaccuracy */ msm->global_learn_count++; bd_config->learn_count++; result0->raw = 0; /* clear all fields */ result0->fields.sw_if_index = sw_if_index0; if (msm->client_pid != 0) l2fib_entry_result_set_LRN_EVT (result0); else l2fib_entry_result_clear_LRN_EVT (result0); } else { /* Entry in L2FIB with different sw_if_index - mac move or filter */ if (l2fib_entry_result_is_set_FILTER (result0)) { ASSERT (result0->fields.sw_if_index == ~0); /* drop packet because lookup matched a filter mac entry */ b0->error = node->errors[L2LEARN_ERROR_FILTER_DROP]; *next0 = L2LEARN_NEXT_DROP; return; } if (l2fib_entry_result_is_set_STATIC (result0)) { /* * Don't overwrite a static mac * TODO: Check violation policy. For now drop the packet */ b0->error = node->errors[L2LEARN_ERROR_MAC_MOVE_VIOLATE]; *next0 = L2LEARN_NEXT_DROP; return; } /* * TODO: may want to rate limit mac moves * TODO: check global/bridge domain/interface learn limits */ result0->fields.sw_if_index = sw_if_index0; if (l2fib_entry_result_is_set_AGE_NOT (result0)) { /* The mac was provisioned */ /* learn_count variable may have little inaccuracy because they are * not incremented/decremented with atomic operations */ /* l2fib_scan is call every 2sec fixing potential inaccuracy */ msm->global_learn_count++; bd_config->learn_count++; l2fib_entry_result_clear_AGE_NOT (result0); } if (msm->client_pid != 0) l2fib_entry_result_set_bits (result0, (L2FIB_ENTRY_RESULT_FLAG_LRN_EVT | L2FIB_ENTRY_RESULT_FLAG_LRN_MOV)); else l2fib_entry_result_clear_bits (result0, (L2FIB_ENTRY_RESULT_FLAG_LRN_EVT | L2FIB_ENTRY_RESULT_FLAG_LRN_MOV)); counter_base[L2LEARN_ERROR_MAC_MOVE] += 1; } /* Update the entry */ result0->fields.timestamp = timestamp; result0->fields.sn = vnet_buffer (b0)->l2.l2fib_sn; BVT (clib_bihash_kv) kv; kv.key = key0->raw; kv.value = result0->raw; BV (clib_bihash_add_del) (msm->mac_table, &kv, 1 /* is_add */ ); /* Invalidate the cache */ cached_key->raw = ~0; } static_always_inline uword l2learn_node_inline (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame, int do_trace) { u32 n_left, *from; l2learn_main_t *msm = &l2learn_main; vlib_node_t *n = vlib_get_node (vm, l2learn_node.index); u32 node_counter_base_index = n->error_heap_index; vlib_error_main_t *em = &vm->error_main; l2fib_entry_key_t cached_key; l2fib_entry_result_t cached_result; u8 timestamp = (u8) (vlib_time_now (vm) / 60); u32 count = 0; vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b; u16 nexts[VLIB_FRAME_SIZE], *next; from = vlib_frame_vector_args (frame); n_left = frame->n_vectors; /* number of packets to process */ vlib_get_buffers (vm, from, bufs, n_left); next = nexts; b = bufs; /* Clear the one-entry cache in case mac table was updated */ cached_key.raw = ~0; cached_result.raw = ~0; /* warning be gone */ while (n_left > 8) { u32 sw_if_index0, sw_if_index1, sw_if_index2, sw_if_index3; const ethernet_header_t *h0, *h1, *h2, *h3; l2fib_entry_key_t key0, key1, key2, key3; l2fib_entry_result_t result0, result1, result2, result3; /* Prefetch next iteration. */ { /* buffer header is read and written, so use LOAD * prefetch */ vlib_prefetch_buffer_header (b[4], LOAD); vlib_prefetch_buffer_header (b[5], LOAD); vlib_prefetch_buffer_header (b[6], LOAD); vlib_prefetch_buffer_header (b[7], LOAD); clib_prefetch_load (b[4]->data); clib_prefetch_load (b[5]->data); clib_prefetch_load (b[6]->data); clib_prefetch_load (b[7]->data); } /* RX interface handles */ sw_if_index0 = vnet_buffer (b[0])->sw_if_index[VLIB_RX]; sw_if_index1 = vnet_buffer (b[1])->sw_if_index[VLIB_RX]; sw_if_index2 = vnet_buffer (b[2])->sw_if_index[VLIB_RX]; sw_if_index3 = vnet_buffer (b[3])->sw_if_index[VLIB_RX]; /* Process 4 x pkts */ h0 = vlib_buffer_get_current (b[0]); h1 = vlib_buffer_get_current (b[1]); h2 = vlib_buffer_get_current (b[2]); h3 = vlib_buffer_get_current (b[3]); if (do_trace) { if (b[0]->flags & VLIB_BUFFER_IS_TRACED) { l2learn_trace_t *t = vlib_add_trace (vm, node, b[0], sizeof (*t)); t->sw_if_index = sw_if_index0; t->bd_index = vnet_buffer (b[0])->l2.bd_index; clib_memcpy_fast (t->src, h0->src_address, 6); clib_memcpy_fast (t->dst, h0->dst_address, 6); } if (b[1]->flags & VLIB_BUFFER_IS_TRACED) { l2learn_trace_t *t = vlib_add_trace (vm, node, b[1], sizeof (*t)); t->sw_if_index = sw_if_index1; t->bd_index = vnet_buffer (b[1])->l2.bd_index; clib_memcpy_fast (t->src, h1->src_address, 6); clib_memcpy_fast (t->dst, h1->dst_address, 6); } if (b[2]->flags & VLIB_BUFFER_IS_TRACED) { l2learn_trace_t *t = vlib_add_trace (vm, node, b[2], sizeof (*t)); t->sw_if_index = sw_if_index2; t->bd_index = vnet_buffer (b[2])->l2.bd_index; clib_memcpy_fast (t->src, h2->src_address, 6); clib_memcpy_fast (t->dst, h2->dst_address, 6); } if (b[3]->flags & VLIB_BUFFER_IS_TRACED) { l2learn_trace_t *t = vlib_add_trace (vm, node, b[3], sizeof (*t)); t->sw_if_index = sw_if_index3; t->bd_index = vnet_buffer (b[3])->l2.bd_index; clib_memcpy_fast (t->src, h3->src_address, 6); clib_memcpy_fast (t->dst, h3->dst_address, 6); } } /* process 4 pkts */ vlib_node_increment_counter (vm, l2learn_node.index, L2LEARN_ERROR_L2LEARN, 4); l2fib_lookup_4 (msm->mac_table, &cached_key, &cached_result, h0->src_address, h1->src_address, h2->src_address, h3->src_address, vnet_buffer (b[0])->l2.bd_index, vnet_buffer (b[1])->l2.bd_index, vnet_buffer (b[2])->l2.bd_index, vnet_buffer (b[3])->l2.bd_index, &key0, &key1, &key2, &key3, &result0, &result1, &result2, &result3); l2learn_process (node, msm, &em->counters[node_counter_base_index], b[0], sw_if_index0, &key0, &cached_key, &count, &result0, next, timestamp); l2learn_process (node, msm, &em->counters[node_counter_base_index], b[1], sw_if_index1, &key1, &cached_key, &count, &result1, next + 1, timestamp); l2learn_process (node, msm, &em->counters[node_counter_base_index], b[2], sw_if_index2, &key2, &cached_key, &count, &result2, next + 2, timestamp); l2learn_process (node, msm, &em->counters[node_counter_base_index], b[3], sw_if_index3, &key3, &cached_key, &count, &result3, next + 3, timestamp); next += 4; b += 4; n_left -= 4; } while (n_left > 0) { u32 sw_if_index0; ethernet_header_t *h0; l2fib_entry_key_t key0; l2fib_entry_result_t result0; sw_if_index0 = vnet_buffer (b[0])->sw_if_index[VLIB_RX]; h0 = vlib_buffer_get_current (b[0]); if (do_trace && PREDICT_FALSE (b[0]->flags & VLIB_BUFFER_IS_TRACED)) { l2learn_trace_t *t = vlib_add_trace (vm, node, b[0], sizeof (*t)); t->sw_if_index = sw_if_index0; t->bd_index = vnet_buffer (b[0])->l2.bd_index; clib_memcpy_fast (t->src, h0->src_address, 6); clib_memcpy_fast (t->dst, h0->dst_address, 6); } /* process 1 pkt */ vlib_node_increment_counter (vm, l2learn_node.index, L2LEARN_ERROR_L2LEARN, 1); l2fib_lookup_1 (msm->mac_table, &cached_key, &cached_result, h0->src_address, vnet_buffer (b[0])->l2.bd_index, &key0, &result0); l2learn_process (node, msm, &em->counters[node_counter_base_index], b[0], sw_if_index0, &key0, &cached_key, &count, &result0, next, timestamp); next += 1; b += 1; n_left -= 1; } vlib_buffer_enqueue_to_next (vm, node, from, nexts, frame->n_vectors); return frame->n_vectors; } VLIB_NODE_FN (l2learn_node) (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame) { if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE))) return l2learn_node_inline (vm, node, frame, 1 /* do_trace */ ); return l2learn_node_inline (vm, node, frame, 0 /* do_trace */ ); } VLIB_REGISTER_NODE (l2learn_node) = { .name = "l2-learn", .vector_size = sizeof (u32), .format_trace = format_l2learn_trace, .type = VLIB_NODE_TYPE_INTERNAL, .n_errors = ARRAY_LEN(l2learn_error_strings), .error_strings = l2learn_error_strings, .n_next_nodes = L2LEARN_N_NEXT, /* edit / add dispositions here */ .next_nodes = { [L2LEARN_NEXT_DROP] = "error-drop", [L2LEARN_NEXT_L2FWD] = "l2-fwd", }, }; #ifndef CLIB_MARCH_VARIANT clib_error_t * l2learn_init (vlib_main_t * vm) { l2learn_main_t *mp = &l2learn_main; mp->vlib_main = vm; mp->vnet_main = vnet_get_main (); /* Initialize the feature next-node indexes */ feat_bitmap_init_next_nodes (vm, l2learn_node.index, L2INPUT_N_FEAT, l2input_get_feat_names (), mp->feat_next_node_index); /* init the hash table ptr */ mp->mac_table = get_mac_table (); /* * Set the default number of dynamically learned macs to the number * of buckets. */ mp->global_learn_limit = L2LEARN_DEFAULT_LIMIT; /* * Set the default number of dynamically learned macs to the number * of buckets. */ mp->bd_default_learn_limit = L2LEARN_DEFAULT_LIMIT; return 0; } VLIB_INIT_FUNCTION (l2learn_init); /** * Set subinterface learn enable/disable. * The CLI format is: * set interface l2 learn [disable] */ static clib_error_t * int_learn (vlib_main_t * vm, unformat_input_t * input, vlib_cli_command_t * cmd) { vnet_main_t *vnm = vnet_get_main (); clib_error_t *error = 0; u32 sw_if_index; u32 enable; if (!unformat_user (input, unformat_vnet_sw_interface, vnm, &sw_if_index)) { error = clib_error_return (0, "unknown interface `%U'", format_unformat_error, input); goto done; } enable = 1; if (unformat (input, "disable")) { enable = 0; } /* set the interface flag */ l2input_intf_bitmap_enable (sw_if_index, L2INPUT_FEAT_LEARN, enable); done: return error; } /*? * Layer 2 learning can be enabled and disabled on each * interface and on each bridge-domain. Use this command to * manage interfaces. It is enabled by default. * * @cliexpar * Example of how to enable learning: * @cliexcmd{set interface l2 learn GigabitEthernet0/8/0} * Example of how to disable learning: * @cliexcmd{set interface l2 learn GigabitEthernet0/8/0 disable} ?*/ VLIB_CLI_COMMAND (int_learn_cli, static) = { .path = "set interface l2 learn", .short_help = "set interface l2 learn [disable]", .function = int_learn, }; static clib_error_t * l2learn_config (vlib_main_t * vm, unformat_input_t * input) { l2learn_main_t *mp = &l2learn_main; while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT) { if (unformat (input, "limit %d", &mp->global_learn_limit)) ; else return clib_error_return (0, "unknown input `%U'", format_unformat_error, input); } return 0; } VLIB_CONFIG_FUNCTION (l2learn_config, "l2learn"); #endif /* * fd.io coding-style-patch-verification: ON * * Local Variables: * eval: (c-set-style "gnu") * End: */