diff options
Diffstat (limited to 'src/plugins/l2tp/decap.c')
| -rw-r--r-- | src/plugins/l2tp/decap.c | 301 |
1 files changed, 301 insertions, 0 deletions
diff --git a/src/plugins/l2tp/decap.c b/src/plugins/l2tp/decap.c new file mode 100644 index 00000000000..8c41bdd2357 --- /dev/null +++ b/src/plugins/l2tp/decap.c @@ -0,0 +1,301 @@ +/* + * decap.c : L2TPv3 tunnel decapsulation + * + * 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 <vppinfra/error.h> +#include <vppinfra/hash.h> +#include <vnet/vnet.h> +#include <vnet/ip/ip.h> +#include <vnet/ethernet/ethernet.h> +#include <l2tp/l2tp.h> +#include <vnet/l2/l2_input.h> + +/* Statistics (not really errors) */ +#define foreach_l2t_decap_error \ +_(USER_TO_NETWORK, "L2TP user (ip6) to L2 network pkts") \ +_(SESSION_ID_MISMATCH, "l2tpv3 local session id mismatches") \ +_(COOKIE_MISMATCH, "l2tpv3 local cookie mismatches") \ +_(NO_SESSION, "l2tpv3 session not found") \ +_(ADMIN_DOWN, "l2tpv3 tunnel is down") + +static char *l2t_decap_error_strings[] = { +#define _(sym,string) string, + foreach_l2t_decap_error +#undef _ +}; + +typedef enum +{ +#define _(sym,str) L2T_DECAP_ERROR_##sym, + foreach_l2t_decap_error +#undef _ + L2T_DECAP_N_ERROR, +} l2t_DECAP_error_t; + +typedef enum +{ + L2T_DECAP_NEXT_DROP, + L2T_DECAP_NEXT_L2_INPUT, + L2T_DECAP_N_NEXT, + /* Pseudo next index */ + L2T_DECAP_NEXT_NO_INTERCEPT = L2T_DECAP_N_NEXT, +} l2t_decap_next_t; + +#define NSTAGES 3 + +static inline void +stage0 (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_buffer_t * b) +{ + vlib_prefetch_buffer_header (b, STORE); + /* l2tpv3 header is a long way away, need 2 cache lines */ + CLIB_PREFETCH (b->data, 2 * CLIB_CACHE_LINE_BYTES, STORE); +} + +static inline void +stage1 (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_buffer_t * b) +{ + l2t_main_t *lm = &l2t_main; + ip6_header_t *ip6 = vlib_buffer_get_current (b); + u32 session_index; + uword *p = 0; + l2tpv3_header_t *l2t; + + /* Not L2tpv3 (0x73, 0t115)? Use the normal path. */ + if (PREDICT_FALSE (ip6->protocol != IP_PROTOCOL_L2TP)) + { + vnet_buffer (b)->l2t.next_index = L2T_DECAP_NEXT_NO_INTERCEPT; + return; + } + + /* Make up your minds, people... */ + switch (lm->lookup_type) + { + case L2T_LOOKUP_SRC_ADDRESS: + p = hash_get_mem (lm->session_by_src_address, &ip6->src_address); + break; + case L2T_LOOKUP_DST_ADDRESS: + p = hash_get_mem (lm->session_by_dst_address, &ip6->dst_address); + break; + case L2T_LOOKUP_SESSION_ID: + l2t = (l2tpv3_header_t *) (ip6 + 1); + p = hash_get (lm->session_by_session_id, l2t->session_id); + break; + default: + ASSERT (0); + } + + if (PREDICT_FALSE (p == 0)) + { + vnet_buffer (b)->l2t.next_index = L2T_DECAP_NEXT_NO_INTERCEPT; + return; + } + else + { + session_index = p[0]; + } + + /* Remember mapping index, prefetch the mini counter */ + vnet_buffer (b)->l2t.next_index = L2T_DECAP_NEXT_L2_INPUT; + vnet_buffer (b)->l2t.session_index = session_index; + + /* $$$$$ prefetch counter */ +} + +static inline u32 +last_stage (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_buffer_t * b) +{ + l2t_main_t *lm = &l2t_main; + ip6_header_t *ip6 = vlib_buffer_get_current (b); + vlib_node_t *n = vlib_get_node (vm, node->node_index); + u32 node_counter_base_index = n->error_heap_index; + vlib_error_main_t *em = &vm->error_main; + l2tpv3_header_t *l2tp; + u32 counter_index; + l2t_session_t *session = 0; + u32 session_index; + u32 next_index; + u8 l2tp_decap_local = (l2t_decap_local_node.index == n->index); + + /* Other-than-output pkt? We're done... */ + if (vnet_buffer (b)->l2t.next_index != L2T_DECAP_NEXT_L2_INPUT) + { + next_index = vnet_buffer (b)->l2t.next_index; + goto done; + } + + em->counters[node_counter_base_index + L2T_DECAP_ERROR_USER_TO_NETWORK] += + 1; + + session_index = vnet_buffer (b)->l2t.session_index; + + counter_index = + session_index_to_counter_index (session_index, + SESSION_COUNTER_USER_TO_NETWORK); + + /* per-mapping byte stats include the ethernet header */ + vlib_increment_combined_counter (&lm->counter_main, + vlib_get_thread_index (), + counter_index, 1 /* packet_increment */ , + vlib_buffer_length_in_chain (vm, b) + + sizeof (ethernet_header_t)); + + session = pool_elt_at_index (lm->sessions, session_index); + + l2tp = vlib_buffer_get_current (b) + sizeof (*ip6); + + if (PREDICT_FALSE (l2tp->session_id != session->local_session_id)) + { + /* Key matched but session id does not. Assume packet is not for us. */ + em->counters[node_counter_base_index + + L2T_DECAP_ERROR_SESSION_ID_MISMATCH] += 1; + next_index = L2T_DECAP_NEXT_NO_INTERCEPT; + goto done; + } + + if (PREDICT_FALSE (l2tp->cookie != session->local_cookie[0])) + { + if (l2tp->cookie != session->local_cookie[1]) + { + /* Key and session ID matched, but cookie doesn't. Drop this packet. */ + b->error = node->errors[L2T_DECAP_ERROR_COOKIE_MISMATCH]; + next_index = L2T_DECAP_NEXT_DROP; + goto done; + } + } + + vnet_buffer (b)->sw_if_index[VLIB_RX] = session->sw_if_index; + + if (PREDICT_FALSE (!(session->admin_up))) + { + b->error = node->errors[L2T_DECAP_ERROR_ADMIN_DOWN]; + next_index = L2T_DECAP_NEXT_DROP; + goto done; + } + + /* strip the ip6 and L2TP header */ + vlib_buffer_advance (b, sizeof (*ip6) + session->l2tp_hdr_size); + + /* Required to make the l2 tag push / pop code work on l2 subifs */ + vnet_update_l2_len (b); + + if (PREDICT_FALSE (b->flags & VLIB_BUFFER_IS_TRACED)) + { + l2t_trace_t *t = vlib_add_trace (vm, node, b, sizeof (*t)); + t->is_user_to_network = 1; + t->our_address.as_u64[0] = ip6->dst_address.as_u64[0]; + t->our_address.as_u64[1] = ip6->dst_address.as_u64[1]; + t->client_address.as_u64[0] = ip6->src_address.as_u64[0]; + t->client_address.as_u64[1] = ip6->src_address.as_u64[1]; + t->session_index = session_index; + } + + return L2T_DECAP_NEXT_L2_INPUT; + +done: + if (next_index == L2T_DECAP_NEXT_NO_INTERCEPT) + { + /* Small behavioral change between l2tp-decap and l2tp-decap-local */ + if (l2tp_decap_local) + { + b->error = node->errors[L2T_DECAP_ERROR_NO_SESSION]; + next_index = L2T_DECAP_NEXT_DROP; + } + else + { + /* Go to next node on the ip6 configuration chain */ + if (PREDICT_TRUE (session != 0)) + vnet_feature_next (&next_index, b); + } + } + + if (PREDICT_FALSE (b->flags & VLIB_BUFFER_IS_TRACED)) + { + l2t_trace_t *t = vlib_add_trace (vm, node, b, sizeof (*t)); + t->is_user_to_network = 1; + t->our_address.as_u64[0] = ip6->dst_address.as_u64[0]; + t->our_address.as_u64[1] = ip6->dst_address.as_u64[1]; + t->client_address.as_u64[0] = ip6->src_address.as_u64[0]; + t->client_address.as_u64[1] = ip6->src_address.as_u64[1]; + t->session_index = ~0; + } + return next_index; +} + +#include <vnet/pipeline.h> + +VLIB_NODE_FN (l2t_decap_node) (vlib_main_t * vm, + vlib_node_runtime_t * node, + vlib_frame_t * frame) +{ + return dispatch_pipeline (vm, node, frame); +} + +/* + * l2tp-decap and l2tp-decap-local have very slightly different behavior. + * When a packet has no associated session l2tp-decap let it go to ip6 forward, + * while l2tp-decap-local drops it. + */ + +/* *INDENT-OFF* */ +VLIB_REGISTER_NODE (l2t_decap_node) = { + .name = "l2tp-decap", + .vector_size = sizeof (u32), + .format_trace = format_l2t_trace, + .type = VLIB_NODE_TYPE_INTERNAL, + + .n_errors = ARRAY_LEN(l2t_decap_error_strings), + .error_strings = l2t_decap_error_strings, + + .n_next_nodes = L2T_DECAP_N_NEXT, + + /* edit / add dispositions here */ + .next_nodes = { + [L2T_DECAP_NEXT_L2_INPUT] = "l2-input", + [L2T_DECAP_NEXT_DROP] = "error-drop", + }, +}; +/* *INDENT-ON* */ + +extern vlib_node_function_t l2t_decap_node_fn; + +/* *INDENT-OFF* */ +VLIB_REGISTER_NODE (l2t_decap_local_node) = { + .function = l2t_decap_node_fn, + .name = "l2tp-decap-local", + .vector_size = sizeof (u32), + .format_trace = format_l2t_trace, + .type = VLIB_NODE_TYPE_INTERNAL, + + .n_errors = ARRAY_LEN(l2t_decap_error_strings), + .error_strings = l2t_decap_error_strings, + + .n_next_nodes = L2T_DECAP_N_NEXT, + + /* edit / add dispositions here */ + .next_nodes = { + [L2T_DECAP_NEXT_L2_INPUT] = "l2-input", + [L2T_DECAP_NEXT_DROP] = "error-drop", + }, +}; +/* *INDENT-ON* */ + +/* + * fd.io coding-style-patch-verification: ON + * + * Local Variables: + * eval: (c-set-style "gnu") + * End: + */ |