diff options
Diffstat (limited to 'vnet/vnet/l2/l2_learn.c')
| -rw-r--r-- | vnet/vnet/l2/l2_learn.c | 504 |
1 files changed, 504 insertions, 0 deletions
diff --git a/vnet/vnet/l2/l2_learn.c b/vnet/vnet/l2/l2_learn.c new file mode 100644 index 00000000000..29315bedc98 --- /dev/null +++ b/vnet/vnet/l2/l2_learn.c @@ -0,0 +1,504 @@ +/* + * 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 <vlib/vlib.h> +#include <vnet/vnet.h> +#include <vnet/pg/pg.h> +#include <vnet/ethernet/ethernet.h> +#include <vlib/cli.h> + +#include <vnet/l2/l2_input.h> +#include <vnet/l2/feat_bitmap.h> +#include <vnet/l2/l2_fib.h> +#include <vnet/l2/l2_learn.h> + +#include <vppinfra/error.h> +#include <vppinfra/hash.h> + +/* + * 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, "L2 learn hits") \ +_(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 * bucket0, + l2fib_entry_result_t * result0, + u32 * next0) +{ + 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)) { + // The entry was in the table, and the sw_if_index matched, the normal case + + // TODO: for dataplane learning and aging, do this: + // if refresh=0 and not a static mac, set refresh=1 + counter_base[L2LEARN_ERROR_HIT] += 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; + goto done; + + } else { + BVT(clib_bihash_kv) kv; + // It is ok to learn + + result0->raw = 0; // clear all fields + result0->fields.sw_if_index = sw_if_index0; + // TODO: set timestamp in entry to clock for dataplane aging + kv.key = key0->raw; + kv.value = result0->raw; + + BV(clib_bihash_add_del) (msm->mac_table, &kv, 1 /* is_add */); + + cached_key->raw = ~0; // invalidate the cache + msm->global_learn_count++; + } + + } else { + + // The entry was in the table, but with the wrong sw_if_index mapping (mac move) + 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; + } else { + // Update the entry + // TODO: may want to rate limit mac moves + // TODO: check global/bridge domain/interface learn limits + BVT(clib_bihash_kv) kv; + + result0->raw = 0; // clear all fields + result0->fields.sw_if_index = sw_if_index0; + + kv.key = key0->raw; + kv.value = result0->raw; + + cached_key->raw = ~0; // invalidate the cache + + BV(clib_bihash_add_del) (msm->mac_table, &kv, 1 /* is_add */); + } + } + + if (result0->fields.filter) { + // drop packet because lookup matched a filter mac entry + + if (*next0 != L2LEARN_NEXT_DROP) { + // if we're not already dropping the packet, do it now + b0->error = node->errors[L2LEARN_ERROR_FILTER_DROP]; + *next0 = L2LEARN_NEXT_DROP; + } + } + +done: + return; +} + + +static uword +l2learn_node_fn (vlib_main_t * vm, + vlib_node_runtime_t * node, + vlib_frame_t * frame) +{ + 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; + + 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 >= 4 && n_left_to_next >= 2) + { + u32 bi0, bi1; + vlib_buffer_t * b0, * b1; + u32 next0, next1; + u32 sw_if_index0, sw_if_index1; + ethernet_header_t * h0, * h1; + l2fib_entry_key_t key0, key1; + l2fib_entry_result_t result0, result1; + u32 bucket0, bucket1; + + /* Prefetch next iteration. */ + { + vlib_buffer_t * p2, * p3; + + p2 = vlib_get_buffer (vm, from[2]); + p3 = vlib_get_buffer (vm, from[3]); + + vlib_prefetch_buffer_header (p2, LOAD); + vlib_prefetch_buffer_header (p3, LOAD); + + CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE); + CLIB_PREFETCH (p3->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]; + from += 2; + to_next += 2; + n_left_from -= 2; + n_left_to_next -= 2; + + b0 = vlib_get_buffer (vm, bi0); + b1 = vlib_get_buffer (vm, bi1); + + /* 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]; + + /* Process 2 x pkts */ + + h0 = vlib_buffer_get_current (b0); + h1 = vlib_buffer_get_current (b1); + + if (PREDICT_FALSE((node->flags & VLIB_NODE_FLAG_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; + memcpy(t->src, h0->src_address, 6); + 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; + memcpy(t->src, h1->src_address, 6); + memcpy(t->dst, h1->dst_address, 6); + } + } + + /* process 2 pkts */ + em->counters[node_counter_base_index + L2LEARN_ERROR_L2LEARN] += 2; + + l2fib_lookup_2 (msm->mac_table, &cached_key, &cached_result, + h0->src_address, + h1->src_address, + vnet_buffer(b0)->l2.bd_index, + vnet_buffer(b1)->l2.bd_index, + &key0, + &key1, + &bucket0, + &bucket1, + &result0, + &result1); + + l2learn_process (node, msm, &em->counters[node_counter_base_index], + b0, sw_if_index0, &key0, &cached_key, + &bucket0, &result0, &next0); + + l2learn_process (node, msm, &em->counters[node_counter_base_index], + b1, sw_if_index1, &key1, &cached_key, + &bucket1, &result1, &next1); + + /* verify speculative enqueues, maybe switch current next frame */ + /* if next0==next1==next_index then nothing special needs to be done */ + vlib_validate_buffer_enqueue_x2 (vm, node, next_index, + to_next, n_left_to_next, + bi0, bi1, next0, next1); + } + + 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 (PREDICT_FALSE((node->flags & VLIB_NODE_FLAG_TRACE) + && (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; + memcpy(t->src, h0->src_address, 6); + memcpy(t->dst, h0->dst_address, 6); + } + + /* process 1 pkt */ + em->counters[node_counter_base_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, + &bucket0, &result0, &next0); + + /* 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; +} + + +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", + }, +}; + + +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 * 16; + + return 0; +} + +VLIB_INIT_FUNCTION (l2learn_init); + + +// set subinterface learn enable/disable +// The CLI format is: +// set interface l2 learn <interface> [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; +} + +VLIB_CLI_COMMAND (int_learn_cli, static) = { + .path = "set interface l2 learn", + .short_help = "set interface l2 learn <interface> [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"); + |