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, vlib_buffer_t * b)
61 vlib_prefetch_buffer_header (b, STORE);
62 /* l2tpv3 header is a long way away, need 2 cache lines */
63 CLIB_PREFETCH (b->data, 2 * CLIB_CACHE_LINE_BYTES, STORE);
67 stage1 (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_buffer_t * b)
69 l2t_main_t *lm = &l2t_main;
70 ip6_header_t *ip6 = vlib_buffer_get_current (b);
75 /* Not L2tpv3 (0x73, 0t115)? Use the normal path. */
76 if (PREDICT_FALSE (ip6->protocol != IP_PROTOCOL_L2TP))
78 vnet_buffer (b)->l2t.next_index = L2T_DECAP_NEXT_NO_INTERCEPT;
82 /* Make up your minds, people... */
83 switch (lm->lookup_type)
85 case L2T_LOOKUP_SRC_ADDRESS:
86 p = hash_get_mem (lm->session_by_src_address, &ip6->src_address);
88 case L2T_LOOKUP_DST_ADDRESS:
89 p = hash_get_mem (lm->session_by_dst_address, &ip6->dst_address);
91 case L2T_LOOKUP_SESSION_ID:
92 l2t = (l2tpv3_header_t *) (ip6 + 1);
93 p = hash_get (lm->session_by_session_id, l2t->session_id);
99 if (PREDICT_FALSE (p == 0))
101 vnet_buffer (b)->l2t.next_index = L2T_DECAP_NEXT_NO_INTERCEPT;
106 session_index = p[0];
109 /* Remember mapping index, prefetch the mini counter */
110 vnet_buffer (b)->l2t.next_index = L2T_DECAP_NEXT_L2_INPUT;
111 vnet_buffer (b)->l2t.session_index = session_index;
113 /* $$$$$ prefetch counter */
117 last_stage (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_buffer_t * b)
119 l2t_main_t *lm = &l2t_main;
120 ip6_header_t *ip6 = vlib_buffer_get_current (b);
121 vlib_node_t *n = vlib_get_node (vm, node->node_index);
122 u32 node_counter_base_index = n->error_heap_index;
123 vlib_error_main_t *em = &vm->error_main;
124 l2tpv3_header_t *l2tp;
126 l2t_session_t *session = 0;
129 u8 l2tp_decap_local = (l2t_decap_local_node.index == n->index);
131 /* Other-than-output pkt? We're done... */
132 if (vnet_buffer (b)->l2t.next_index != L2T_DECAP_NEXT_L2_INPUT)
134 next_index = vnet_buffer (b)->l2t.next_index;
138 em->counters[node_counter_base_index + L2T_DECAP_ERROR_USER_TO_NETWORK] +=
141 session_index = vnet_buffer (b)->l2t.session_index;
144 session_index_to_counter_index (session_index,
145 SESSION_COUNTER_USER_TO_NETWORK);
147 /* per-mapping byte stats include the ethernet header */
148 vlib_increment_combined_counter (&lm->counter_main,
149 vlib_get_thread_index (),
150 counter_index, 1 /* packet_increment */ ,
151 vlib_buffer_length_in_chain (vm, b) +
152 sizeof (ethernet_header_t));
154 session = pool_elt_at_index (lm->sessions, session_index);
156 l2tp = vlib_buffer_get_current (b) + sizeof (*ip6);
158 if (PREDICT_FALSE (l2tp->session_id != session->local_session_id))
160 /* Key matched but session id does not. Assume packet is not for us. */
161 em->counters[node_counter_base_index +
162 L2T_DECAP_ERROR_SESSION_ID_MISMATCH] += 1;
163 next_index = L2T_DECAP_NEXT_NO_INTERCEPT;
167 if (PREDICT_FALSE (l2tp->cookie != session->local_cookie[0]))
169 if (l2tp->cookie != session->local_cookie[1])
171 /* Key and session ID matched, but cookie doesn't. Drop this packet. */
172 b->error = node->errors[L2T_DECAP_ERROR_COOKIE_MISMATCH];
173 next_index = L2T_DECAP_NEXT_DROP;
178 vnet_buffer (b)->sw_if_index[VLIB_RX] = session->sw_if_index;
180 if (PREDICT_FALSE (!(session->admin_up)))
182 b->error = node->errors[L2T_DECAP_ERROR_ADMIN_DOWN];
183 next_index = L2T_DECAP_NEXT_DROP;
187 /* strip the ip6 and L2TP header */
188 vlib_buffer_advance (b, sizeof (*ip6) + session->l2tp_hdr_size);
190 /* Required to make the l2 tag push / pop code work on l2 subifs */
191 vnet_update_l2_len (b);
193 if (PREDICT_FALSE (b->flags & VLIB_BUFFER_IS_TRACED))
195 l2t_trace_t *t = vlib_add_trace (vm, node, b, sizeof (*t));
196 t->is_user_to_network = 1;
197 t->our_address.as_u64[0] = ip6->dst_address.as_u64[0];
198 t->our_address.as_u64[1] = ip6->dst_address.as_u64[1];
199 t->client_address.as_u64[0] = ip6->src_address.as_u64[0];
200 t->client_address.as_u64[1] = ip6->src_address.as_u64[1];
201 t->session_index = session_index;
204 return L2T_DECAP_NEXT_L2_INPUT;
207 if (next_index == L2T_DECAP_NEXT_NO_INTERCEPT)
209 /* Small behavioral change between l2tp-decap and l2tp-decap-local */
210 if (l2tp_decap_local)
212 b->error = node->errors[L2T_DECAP_ERROR_NO_SESSION];
213 next_index = L2T_DECAP_NEXT_DROP;
217 /* Go to next node on the ip6 configuration chain */
218 if (PREDICT_TRUE (session != 0))
219 vnet_feature_next (&next_index, b);
223 if (PREDICT_FALSE (b->flags & VLIB_BUFFER_IS_TRACED))
225 l2t_trace_t *t = vlib_add_trace (vm, node, b, sizeof (*t));
226 t->is_user_to_network = 1;
227 t->our_address.as_u64[0] = ip6->dst_address.as_u64[0];
228 t->our_address.as_u64[1] = ip6->dst_address.as_u64[1];
229 t->client_address.as_u64[0] = ip6->src_address.as_u64[0];
230 t->client_address.as_u64[1] = ip6->src_address.as_u64[1];
231 t->session_index = ~0;
236 #include <vnet/pipeline.h>
239 l2t_decap_node_fn (vlib_main_t * vm,
240 vlib_node_runtime_t * node, vlib_frame_t * frame)
242 return dispatch_pipeline (vm, node, frame);
246 * l2tp-decap and l2tp-decap-local have very slightly different behavior.
247 * When a packet has no associated session l2tp-decap let it go to ip6 forward,
248 * while l2tp-decap-local drops it.
252 VLIB_REGISTER_NODE (l2t_decap_node) = {
253 .function = l2t_decap_node_fn,
254 .name = "l2tp-decap",
255 .vector_size = sizeof (u32),
256 .format_trace = format_l2t_trace,
257 .type = VLIB_NODE_TYPE_INTERNAL,
259 .n_errors = ARRAY_LEN(l2t_decap_error_strings),
260 .error_strings = l2t_decap_error_strings,
262 .n_next_nodes = L2T_DECAP_N_NEXT,
264 /* edit / add dispositions here */
266 [L2T_DECAP_NEXT_L2_INPUT] = "l2-input",
267 [L2T_DECAP_NEXT_DROP] = "error-drop",
272 VLIB_NODE_FUNCTION_MULTIARCH (l2t_decap_node, l2t_decap_node_fn);
274 VLIB_REGISTER_NODE (l2t_decap_local_node) = {
275 .function = l2t_decap_node_fn,
276 .name = "l2tp-decap-local",
277 .vector_size = sizeof (u32),
278 .format_trace = format_l2t_trace,
279 .type = VLIB_NODE_TYPE_INTERNAL,
281 .n_errors = ARRAY_LEN(l2t_decap_error_strings),
282 .error_strings = l2t_decap_error_strings,
284 .n_next_nodes = L2T_DECAP_N_NEXT,
286 /* edit / add dispositions here */
288 [L2T_DECAP_NEXT_L2_INPUT] = "l2-input",
289 [L2T_DECAP_NEXT_DROP] = "error-drop",
295 l2tp_decap_init (void)
297 ip6_register_protocol (IP_PROTOCOL_L2TP, l2t_decap_local_node.index);
301 * fd.io coding-style-patch-verification: ON
304 * eval: (c-set-style "gnu")