2 * decap.c : L2TPv3 tunnel decapsulation
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 <vppinfra/error.h>
19 #include <vppinfra/hash.h>
20 #include <vnet/vnet.h>
21 #include <vnet/ip/ip.h>
22 #include <vnet/ethernet/ethernet.h>
23 #include <vnet/l2tp/l2tp.h>
25 /* Statistics (not really errors) */
26 #define foreach_l2t_decap_error \
27 _(USER_TO_NETWORK, "L2TP user (ip6) to L2 network pkts") \
28 _(SESSION_ID_MISMATCH, "l2tpv3 local session id mismatches") \
29 _(COOKIE_MISMATCH, "l2tpv3 local cookie mismatches") \
30 _(NO_SESSION, "l2tpv3 session not found") \
31 _(ADMIN_DOWN, "l2tpv3 tunnel is down")
33 static char *l2t_decap_error_strings[] = {
34 #define _(sym,string) string,
35 foreach_l2t_decap_error
41 #define _(sym,str) L2T_DECAP_ERROR_##sym,
42 foreach_l2t_decap_error
50 L2T_DECAP_NEXT_L2_INPUT,
52 /* Pseudo next index */
53 L2T_DECAP_NEXT_NO_INTERCEPT = L2T_DECAP_N_NEXT,
59 stage0 (vlib_main_t * vm, vlib_node_runtime_t * node, u32 buffer_index)
61 vlib_buffer_t *b = vlib_get_buffer (vm, buffer_index);
62 vlib_prefetch_buffer_header (b, STORE);
63 /* l2tpv3 header is a long way away, need 2 cache lines */
64 CLIB_PREFETCH (b->data, 2 * CLIB_CACHE_LINE_BYTES, STORE);
68 stage1 (vlib_main_t * vm, vlib_node_runtime_t * node, u32 bi)
70 vlib_buffer_t *b = vlib_get_buffer (vm, bi);
71 l2t_main_t *lm = &l2t_main;
72 ip6_header_t *ip6 = vlib_buffer_get_current (b);
77 /* Not L2tpv3 (0x73, 0t115)? Use the normal path. */
78 if (PREDICT_FALSE (ip6->protocol != IP_PROTOCOL_L2TP))
80 vnet_buffer (b)->l2t.next_index = L2T_DECAP_NEXT_NO_INTERCEPT;
84 /* Make up your minds, people... */
85 switch (lm->lookup_type)
87 case L2T_LOOKUP_SRC_ADDRESS:
88 p = hash_get_mem (lm->session_by_src_address, &ip6->src_address);
90 case L2T_LOOKUP_DST_ADDRESS:
91 p = hash_get_mem (lm->session_by_dst_address, &ip6->dst_address);
93 case L2T_LOOKUP_SESSION_ID:
94 l2t = (l2tpv3_header_t *) (ip6 + 1);
95 p = hash_get (lm->session_by_session_id, l2t->session_id);
101 if (PREDICT_FALSE (p == 0))
103 vnet_buffer (b)->l2t.next_index = L2T_DECAP_NEXT_NO_INTERCEPT;
108 session_index = p[0];
111 /* Remember mapping index, prefetch the mini counter */
112 vnet_buffer (b)->l2t.next_index = L2T_DECAP_NEXT_L2_INPUT;
113 vnet_buffer (b)->l2t.session_index = session_index;
115 /* $$$$$ prefetch counter */
119 last_stage (vlib_main_t * vm, vlib_node_runtime_t * node, u32 bi)
121 vlib_buffer_t *b = vlib_get_buffer (vm, bi);
122 l2t_main_t *lm = &l2t_main;
123 ip6_header_t *ip6 = vlib_buffer_get_current (b);
124 vlib_node_t *n = vlib_get_node (vm, node->node_index);
125 u32 node_counter_base_index = n->error_heap_index;
126 vlib_error_main_t *em = &vm->error_main;
127 l2tpv3_header_t *l2tp;
129 l2t_session_t *session = 0;
132 u8 l2tp_decap_local = (l2t_decap_local_node.index == n->index);
134 /* Other-than-output pkt? We're done... */
135 if (vnet_buffer (b)->l2t.next_index != L2T_DECAP_NEXT_L2_INPUT)
137 next_index = vnet_buffer (b)->l2t.next_index;
141 em->counters[node_counter_base_index + L2T_DECAP_ERROR_USER_TO_NETWORK] +=
144 session_index = vnet_buffer (b)->l2t.session_index;
147 session_index_to_counter_index (session_index,
148 SESSION_COUNTER_USER_TO_NETWORK);
150 /* per-mapping byte stats include the ethernet header */
151 vlib_increment_combined_counter (&lm->counter_main,
152 vlib_get_thread_index (),
153 counter_index, 1 /* packet_increment */ ,
154 vlib_buffer_length_in_chain (vm, b) +
155 sizeof (ethernet_header_t));
157 session = pool_elt_at_index (lm->sessions, session_index);
159 l2tp = vlib_buffer_get_current (b) + sizeof (*ip6);
161 if (PREDICT_FALSE (l2tp->session_id != session->local_session_id))
163 /* Key matched but session id does not. Assume packet is not for us. */
164 em->counters[node_counter_base_index +
165 L2T_DECAP_ERROR_SESSION_ID_MISMATCH] += 1;
166 next_index = L2T_DECAP_NEXT_NO_INTERCEPT;
170 if (PREDICT_FALSE (l2tp->cookie != session->local_cookie[0]))
172 if (l2tp->cookie != session->local_cookie[1])
174 /* Key and session ID matched, but cookie doesn't. Drop this packet. */
175 b->error = node->errors[L2T_DECAP_ERROR_COOKIE_MISMATCH];
176 next_index = L2T_DECAP_NEXT_DROP;
181 vnet_buffer (b)->sw_if_index[VLIB_RX] = session->sw_if_index;
183 if (PREDICT_FALSE (!(session->admin_up)))
185 b->error = node->errors[L2T_DECAP_ERROR_ADMIN_DOWN];
186 next_index = L2T_DECAP_NEXT_DROP;
190 /* strip the ip6 and L2TP header */
191 vlib_buffer_advance (b, sizeof (*ip6) + session->l2tp_hdr_size);
193 /* Required to make the l2 tag push / pop code work on l2 subifs */
194 vnet_update_l2_len (b);
196 if (PREDICT_FALSE (b->flags & VLIB_BUFFER_IS_TRACED))
198 l2t_trace_t *t = vlib_add_trace (vm, node, b, sizeof (*t));
199 t->is_user_to_network = 1;
200 t->our_address.as_u64[0] = ip6->dst_address.as_u64[0];
201 t->our_address.as_u64[1] = ip6->dst_address.as_u64[1];
202 t->client_address.as_u64[0] = ip6->src_address.as_u64[0];
203 t->client_address.as_u64[1] = ip6->src_address.as_u64[1];
204 t->session_index = session_index;
207 return L2T_DECAP_NEXT_L2_INPUT;
210 if (next_index == L2T_DECAP_NEXT_NO_INTERCEPT)
212 /* Small behavioral change between l2tp-decap and l2tp-decap-local */
213 if (l2tp_decap_local)
215 b->error = node->errors[L2T_DECAP_ERROR_NO_SESSION];
216 next_index = L2T_DECAP_NEXT_DROP;
220 /* Go to next node on the ip6 configuration chain */
221 if (PREDICT_TRUE (session != 0))
222 vnet_feature_next (session->sw_if_index, &next_index, b);
226 if (PREDICT_FALSE (b->flags & VLIB_BUFFER_IS_TRACED))
228 l2t_trace_t *t = vlib_add_trace (vm, node, b, sizeof (*t));
229 t->is_user_to_network = 1;
230 t->our_address.as_u64[0] = ip6->dst_address.as_u64[0];
231 t->our_address.as_u64[1] = ip6->dst_address.as_u64[1];
232 t->client_address.as_u64[0] = ip6->src_address.as_u64[0];
233 t->client_address.as_u64[1] = ip6->src_address.as_u64[1];
234 t->session_index = ~0;
239 #include <vnet/pipeline.h>
242 l2t_decap_node_fn (vlib_main_t * vm,
243 vlib_node_runtime_t * node, vlib_frame_t * frame)
245 return dispatch_pipeline (vm, node, frame);
249 * l2tp-decap and l2tp-decap-local have very slightly different behavior.
250 * When a packet has no associated session l2tp-decap let it go to ip6 forward,
251 * while l2tp-decap-local drops it.
255 VLIB_REGISTER_NODE (l2t_decap_node) = {
256 .function = l2t_decap_node_fn,
257 .name = "l2tp-decap",
258 .vector_size = sizeof (u32),
259 .format_trace = format_l2t_trace,
260 .type = VLIB_NODE_TYPE_INTERNAL,
262 .n_errors = ARRAY_LEN(l2t_decap_error_strings),
263 .error_strings = l2t_decap_error_strings,
265 .n_next_nodes = L2T_DECAP_N_NEXT,
267 /* edit / add dispositions here */
269 [L2T_DECAP_NEXT_L2_INPUT] = "l2-input",
270 [L2T_DECAP_NEXT_DROP] = "error-drop",
275 VLIB_NODE_FUNCTION_MULTIARCH (l2t_decap_node, l2t_decap_node_fn);
277 VLIB_REGISTER_NODE (l2t_decap_local_node) = {
278 .function = l2t_decap_node_fn,
279 .name = "l2tp-decap-local",
280 .vector_size = sizeof (u32),
281 .format_trace = format_l2t_trace,
282 .type = VLIB_NODE_TYPE_INTERNAL,
284 .n_errors = ARRAY_LEN(l2t_decap_error_strings),
285 .error_strings = l2t_decap_error_strings,
287 .n_next_nodes = L2T_DECAP_N_NEXT,
289 /* edit / add dispositions here */
291 [L2T_DECAP_NEXT_L2_INPUT] = "l2-input",
292 [L2T_DECAP_NEXT_DROP] = "error-drop",
298 l2tp_decap_init (void)
300 ip6_register_protocol (IP_PROTOCOL_L2TP, l2t_decap_local_node.index);
304 * fd.io coding-style-patch-verification: ON
307 * eval: (c-set-style "gnu")