/* * 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 #include /** * @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; } static 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, u32 * next0, u8 timestamp) { u32 feature_bitmap; /* Set up the default next node (typically L2FWD) */ /* Remove ourself from the feature bitmap */ feature_bitmap = vnet_buffer (b0)->l2.feature_bitmap & ~L2INPUT_FEAT_LEARN; /* Save for next feature graph nodes */ vnet_buffer (b0)->l2.feature_bitmap = feature_bitmap; /* Determine the next node */ *next0 = feat_bitmap_get_next_node_index (msm->feat_next_node_index, feature_bitmap); /* 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.as_u16 - vnet_buffer (b0)->l2.l2fib_sn; u32 check = dtime | dsn; if (PREDICT_TRUE (check == 0)) return; if (result0->fields.static_mac) return; /* 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 */ if ((*count > 2) && (dtime == 1)) return; counter_base[L2LEARN_ERROR_HIT_UPDATE] += 1; *count += 1; } else if (result0->raw == ~0) { /* The entry was not in table, so add it */ counter_base[L2LEARN_ERROR_MISS] += 1; if (msm->global_learn_count == msm->global_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; } /* It is ok to learn */ msm->global_learn_count++; result0->raw = 0; /* clear all fields */ result0->fields.sw_if_index = sw_if_index0; } else { /* The entry was in the table, but with the wrong sw_if_index mapping (mac move) */ if (result0->fields.filter) { 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; } counter_base[L2LEARN_ERROR_MAC_MOVE] += 1; if (result0->fields.static_mac) { /* * 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; } /* Update the entry */ result0->fields.timestamp = timestamp; result0->fields.sn.as_u16 = 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, *from, *to_next; l2learn_next_t next_index; 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; from = vlib_frame_vector_args (frame); n_left_from = frame->n_vectors; /* number of packets to process */ next_index = node->cached_next_index; /* 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_from > 0) { u32 n_left_to_next; /* get space to enqueue frame to graph node "next_index" */ vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next); while (n_left_from >= 8 && n_left_to_next >= 4) { u32 bi0, bi1, bi2, bi3; vlib_buffer_t *b0, *b1, *b2, *b3; u32 next0, next1, next2, next3; u32 sw_if_index0, sw_if_index1, sw_if_index2, sw_if_index3; ethernet_header_t *h0, *h1, *h2, *h3; l2fib_entry_key_t key0, key1, key2, key3; l2fib_entry_result_t result0, result1, result2, result3; u32 bucket0, bucket1, bucket2, bucket3; /* Prefetch next iteration. */ { vlib_buffer_t *p4, *p5, *p6, *p7;; p4 = vlib_get_buffer (vm, from[4]); p5 = vlib_get_buffer (vm, from[5]); p6 = vlib_get_buffer (vm, from[6]); p7 = vlib_get_buffer (vm, from[7]); vlib_prefetch_buffer_header (p4, LOAD); vlib_prefetch_buffer_header (p5, LOAD); vlib_prefetch_buffer_header (p6, LOAD); vlib_prefetch_buffer_header (p7, LOAD); CLIB_PREFETCH (p4->data, CLIB_CACHE_LINE_BYTES, STORE); CLIB_PREFETCH (p5->data, CLIB_CACHE_LINE_BYTES, STORE); CLIB_PREFETCH (p6->data, CLIB_CACHE_LINE_BYTES, STORE); CLIB_PREFETCH (p7->data, CLIB_CACHE_LINE_BYTES, STORE); } /* speculatively enqueue b0 and b1 to the current next frame */ /* bi is "buffer index", b is pointer to the buffer */ to_next[0] = bi0 = from[0]; to_next[1] = bi1 = from[1]; to_next[2] = bi2 = from[2]; to_next[3] = bi3 = from[3]; from += 4; to_next += 4; n_left_from -= 4; n_left_to_next -= 4; b0 = vlib_get_buffer (vm, bi0); b1 = vlib_get_buffer (vm, bi1); b2 = vlib_get_buffer (vm, bi2); b3 = vlib_get_buffer (vm, bi3); /* RX interface handles */ sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX]; sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX]; sw_if_index2 = vnet_buffer (b2)->sw_if_index[VLIB_RX]; sw_if_index3 = vnet_buffer (b3)->sw_if_index[VLIB_RX]; /* Process 4 x pkts */ h0 = vlib_buffer_get_current (b0); h1 = vlib_buffer_get_current (b1); h2 = vlib_buffer_get_current (b2); h3 = vlib_buffer_get_current (b3); if (do_trace) { if (b0->flags & VLIB_BUFFER_IS_TRACED) { l2learn_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t)); t->sw_if_index = sw_if_index0; t->bd_index = vnet_buffer (b0)->l2.bd_index; clib_memcpy (t->src, h0->src_address, 6); clib_memcpy (t->dst, h0->dst_address, 6); } if (b1->flags & VLIB_BUFFER_IS_TRACED) { l2learn_trace_t *t = vlib_add_trace (vm, node, b1, sizeof (*t)); t->sw_if_index = sw_if_index1; t->bd_index = vnet_buffer (b1)->l2.bd_index; clib_memcpy (t->src, h1->src_address, 6); clib_memcpy (t->dst, h1->dst_address, 6); } if (b2->flags & VLIB_BUFFER_IS_TRACED) { l2learn_trace_t *t = vlib_add_trace (vm, node, b2, sizeof (*t)); t->sw_if_index = sw_if_index2; t->bd_index = vnet_buffer (b2)->l2.bd_index; clib_memcpy (t->src, h2->src_address, 6); clib_memcpy (t->dst, h2->dst_address, 6); } if (b3->flags & VLIB_BUFFER_IS_TRACED) { l2learn_trace_t *t = vlib_add_trace (vm, node, b3, sizeof (*t)); t->sw_if_index = sw_if_index3; t->bd_index = vnet_buffer (b3)->l2.bd_index; clib_memcpy (t->src, h3->src_address, 6); clib_memcpy (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 (b0)->l2.bd_index, vnet_buffer (b1)->l2.bd_index, vnet_buffer (b2)->l2.bd_index, vnet_buffer (b3)->l2.bd_index, &key0, &key1, &key2, &key3, &bucket0, &bucket1, &bucket2, &bucket3, &result0, &result1, &result2, &result3); l2learn_process (node, msm, &em->counters[node_counter_base_index], b0, sw_if_index0, &key0, &cached_key, &count, &result0, &next0, timestamp); l2learn_process (node, msm, &em->counters[node_counter_base_index], b1, sw_if_index1, &key1, &cached_key, &count, &result1, &next1, timestamp); l2learn_process (node, msm, &em->counters[node_counter_base_index], b2, sw_if_index2, &key2, &cached_key, &count, &result2, &next2, timestamp); l2learn_process (node, msm, &em->counters[node_counter_base_index], b3, sw_if_index3, &key3, &cached_key, &count, &result3, &next3, timestamp); /* verify speculative enqueues, maybe switch current next frame */ /* if next0==next1==next_index then nothing special needs to be done */ vlib_validate_buffer_enqueue_x4 (vm, node, next_index, to_next, n_left_to_next, bi0, bi1, bi2, bi3, next0, next1, next2, next3); } while (n_left_from > 0 && n_left_to_next > 0) { u32 bi0; vlib_buffer_t *b0; u32 next0; u32 sw_if_index0; ethernet_header_t *h0; l2fib_entry_key_t key0; l2fib_entry_result_t result0; u32 bucket0; /* speculatively enqueue b0 to the current next frame */ bi0 = from[0]; to_next[0] = bi0; from += 1; to_next += 1; n_left_from -= 1; n_left_to_next -= 1; b0 = vlib_get_buffer (vm, bi0); sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX]; h0 = vlib_buffer_get_current (b0); if (do_trace && PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED)) { l2learn_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t)); t->sw_if_index = sw_if_index0; t->bd_index = vnet_buffer (b0)->l2.bd_index; clib_memcpy (t->src, h0->src_address, 6); clib_memcpy (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 (b0)->l2.bd_index, &key0, &bucket0, &result0); l2learn_process (node, msm, &em->counters[node_counter_base_index], b0, sw_if_index0, &key0, &cached_key, &count, &result0, &next0, timestamp); /* verify speculative enqueue, maybe switch current next frame */ vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next, n_left_to_next, bi0, next0); } vlib_put_next_frame (vm, node, next_index, n_left_to_next); } return frame->n_vectors; } static uword l2learn_node_fn (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 */ ); } /* *INDENT-OFF* */ VLIB_REGISTER_NODE (l2learn_node,static) = { .function = l2learn_node_fn, .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", }, }; /* *INDENT-ON* */ VLIB_NODE_FUNCTION_MULTIARCH (l2learn_node, l2learn_node_fn) 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 = L2FIB_NUM_BUCKETS * 64; 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} ?*/ /* *INDENT-OFF* */ VLIB_CLI_COMMAND (int_learn_cli, static) = { .path = "set interface l2 learn", .short_help = "set interface l2 learn [disable]", .function = int_learn, }; /* *INDENT-ON* */ 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"); /* * fd.io coding-style-patch-verification: ON * * Local Variables: * eval: (c-set-style "gnu") * End: */