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
40 #define _(sym,str) L2T_DECAP_ERROR_##sym,
41 foreach_l2t_decap_error
48 L2T_DECAP_NEXT_L2_INPUT,
50 /* Pseudo next index */
51 L2T_DECAP_NEXT_NO_INTERCEPT = L2T_DECAP_N_NEXT,
56 static inline void stage0 (vlib_main_t * vm,
57 vlib_node_runtime_t * node,
60 vlib_buffer_t *b = vlib_get_buffer (vm, buffer_index);
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);
66 static inline void stage1 (vlib_main_t * vm,
67 vlib_node_runtime_t * node,
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);
75 l2tpv3_header_t * l2t;
77 /* Not L2tpv3 (0x73, 0t115)? Use the normal path. */
78 if (PREDICT_FALSE(ip6->protocol != IP_PROTOCOL_L2TP)) {
79 vnet_buffer(b)->l2t.next_index = L2T_DECAP_NEXT_NO_INTERCEPT;
83 /* Make up your minds, people... */
84 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)) {
100 vnet_buffer(b)->l2t.next_index = L2T_DECAP_NEXT_NO_INTERCEPT;
103 session_index = p[0];
106 /* Remember mapping index, prefetch the mini counter */
107 vnet_buffer(b)->l2t.next_index = L2T_DECAP_NEXT_L2_INPUT;
108 vnet_buffer(b)->l2t.session_index = session_index;
110 /* $$$$$ prefetch counter */
113 static inline u32 last_stage (vlib_main_t *vm, vlib_node_runtime_t *node,
116 vlib_buffer_t *b = vlib_get_buffer (vm, bi);
117 l2t_main_t *lm = &l2t_main;
118 ip6_header_t * ip6 = vlib_buffer_get_current (b);
119 vlib_node_t *n = vlib_get_node (vm, node->node_index);
120 u32 node_counter_base_index = n->error_heap_index;
121 vlib_error_main_t * em = &vm->error_main;
122 l2tpv3_header_t * l2tp;
124 l2t_session_t * session;
127 u8 l2tp_decap_local = (l2t_decap_local_node.index == n->index);
129 /* Other-than-output pkt? We're done... */
130 if (vnet_buffer(b)->l2t.next_index != L2T_DECAP_NEXT_L2_INPUT) {
131 next_index = vnet_buffer(b)->l2t.next_index;
135 em->counters[node_counter_base_index + L2T_DECAP_ERROR_USER_TO_NETWORK] += 1;
137 session_index = vnet_buffer(b)->l2t.session_index;
140 session_index_to_counter_index (session_index,
141 SESSION_COUNTER_USER_TO_NETWORK);
143 /* per-mapping byte stats include the ethernet header */
144 vlib_increment_combined_counter (&lm->counter_main,
147 1 /* packet_increment */,
148 vlib_buffer_length_in_chain (vm, b) +
149 sizeof (ethernet_header_t));
151 session = pool_elt_at_index (lm->sessions, session_index);
153 l2tp = vlib_buffer_get_current (b) + sizeof (*ip6);
155 if (PREDICT_FALSE(l2tp->session_id != session->local_session_id)) {
156 // Key matched but session id does not. Assume packet is not for us.
157 em->counters[node_counter_base_index + L2T_DECAP_ERROR_SESSION_ID_MISMATCH] += 1;
158 next_index = L2T_DECAP_NEXT_NO_INTERCEPT;
162 if (PREDICT_FALSE (l2tp->cookie != session->local_cookie[0])) {
163 if (l2tp->cookie != session->local_cookie[1]) {
164 // Key and session ID matched, but cookie doesn't. Drop this packet.
165 b->error = node->errors[L2T_DECAP_ERROR_COOKIE_MISMATCH];
166 next_index = L2T_DECAP_NEXT_DROP;
171 vnet_buffer(b)->sw_if_index[VLIB_RX] = session->sw_if_index;
173 if (PREDICT_FALSE(!(session->admin_up))) {
174 b->error = node->errors[L2T_DECAP_ERROR_ADMIN_DOWN];
175 next_index = L2T_DECAP_NEXT_DROP;
179 /* strip the ip6 and L2TP header */
180 vlib_buffer_advance (b, sizeof (*ip6) + session->l2tp_hdr_size);
182 /* Required to make the l2 tag push / pop code work on l2 subifs */
183 vnet_update_l2_len (b);
185 if (PREDICT_FALSE(b->flags & VLIB_BUFFER_IS_TRACED)) {
186 l2t_trace_t *t = vlib_add_trace (vm, node, b, sizeof (*t));
187 t->is_user_to_network = 1;
188 t->our_address.as_u64[0] =
189 ip6->dst_address.as_u64[0];
190 t->our_address.as_u64[1] =
191 ip6->dst_address.as_u64[1];
192 t->client_address.as_u64[0] =
193 ip6->src_address.as_u64[0];
194 t->client_address.as_u64[1] =
195 ip6->src_address.as_u64[1];
196 t->session_index = session_index;
199 return L2T_DECAP_NEXT_L2_INPUT;
202 if (next_index == L2T_DECAP_NEXT_NO_INTERCEPT) {
203 // Small behavioral change between l2tp-decap and l2tp-decap-local
204 if (l2tp_decap_local) {
205 b->error = node->errors[L2T_DECAP_ERROR_NO_SESSION];
206 next_index = L2T_DECAP_NEXT_DROP;
208 // Go to next node on the ip6 configuration chain
209 ip6_main_t * im = &ip6_main;
210 ip_lookup_main_t * lm = &im->lookup_main;
211 ip_config_main_t * cm = &lm->rx_config_mains[VNET_UNICAST];
212 ip6_l2tpv3_config_t * c0;
214 vnet_get_config_data (&cm->config_main,
215 &b->current_config_index,
221 if (PREDICT_FALSE(b->flags & VLIB_BUFFER_IS_TRACED)) {
222 l2t_trace_t *t = vlib_add_trace (vm, node, b, sizeof (*t));
223 t->is_user_to_network = 1;
224 t->our_address.as_u64[0] =
225 ip6->dst_address.as_u64[0];
226 t->our_address.as_u64[1] =
227 ip6->dst_address.as_u64[1];
228 t->client_address.as_u64[0] =
229 ip6->src_address.as_u64[0];
230 t->client_address.as_u64[1] =
231 ip6->src_address.as_u64[1];
232 t->session_index = ~0;
237 #include <vnet/pipeline.h>
239 static uword l2t_decap_node_fn (vlib_main_t * vm,
240 vlib_node_runtime_t * node,
241 vlib_frame_t * frame)
243 return dispatch_pipeline (vm, node, frame);
247 * l2tp-decap and l2tp-decap-local have very slightly different behavior.
248 * When a packet has no associated session l2tp-decap let it go to ip6 forward,
249 * 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",
271 VLIB_NODE_FUNCTION_MULTIARCH (l2t_decap_node, l2t_decap_node_fn)
273 VLIB_REGISTER_NODE (l2t_decap_local_node) = {
274 .function = l2t_decap_node_fn,
275 .name = "l2tp-decap-local",
276 .vector_size = sizeof (u32),
277 .format_trace = format_l2t_trace,
278 .type = VLIB_NODE_TYPE_INTERNAL,
280 .n_errors = ARRAY_LEN(l2t_decap_error_strings),
281 .error_strings = l2t_decap_error_strings,
283 .n_next_nodes = L2T_DECAP_N_NEXT,
285 /* edit / add dispositions here */
287 [L2T_DECAP_NEXT_L2_INPUT] = "l2-input",
288 [L2T_DECAP_NEXT_DROP] = "error-drop",
292 void l2tp_decap_init (void)
294 ip6_register_protocol (IP_PROTOCOL_L2TP, l2t_decap_local_node.index);