2 * Copyright (c) 2017 Cisco and/or its affiliates.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at:
7 * http://www.apache.org/licenses/LICENSE-2.0
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
17 #include <vlibapi/api.h>
18 #include <vlibmemory/api.h>
20 #include <vlib/vlib.h>
21 #include <vnet/vnet.h>
23 /* define message IDs */
24 #include <dns/dns.api_enum.h>
25 #include <dns/dns.api_types.h>
27 #include <vlibapi/api_helper_macros.h>
30 vnet_dns_response_to_reply (u8 * response,
31 vl_api_dns_resolve_name_reply_t * rmp,
34 vnet_dns_response_to_name (u8 * response,
35 vl_api_dns_resolve_ip_reply_t * rmp,
39 resolve_event (dns_main_t * dm, f64 now, u8 * reply)
41 vlib_main_t *vm = dm->vlib_main;
42 dns_pending_request_t *pr;
45 dns_cache_entry_t *ep;
54 d = (dns_header_t *) reply;
55 flags = clib_net_to_host_u16 (d->flags);
56 rcode = flags & DNS_RCODE_MASK;
58 /* $$$ u16 limits cache to 65K entries, fix later multiple dst ports */
59 pool_index = clib_net_to_host_u16 (d->id);
60 dns_cache_lock (dm, 10);
62 if (pool_is_free_index (dm->entries, pool_index))
66 clib_warning ("pool index %d is free", pool_index);
67 vlib_node_increment_counter (vm, dns46_reply_node.index,
68 DNS46_REPLY_ERROR_NO_ELT, 1);
69 dns_cache_unlock (dm);
73 ep = pool_elt_at_index (dm->entries, pool_index);
76 vec_free (ep->dns_response);
78 /* Handle [sic] recursion AKA CNAME indirection */
79 rv = vnet_dns_cname_indirection_nolock (dm, pool_index, reply);
81 /* CNAME found, further resolution pending, we're done here */
84 dns_cache_unlock (dm);
87 /* Server backfire: refused to answer, or sent zero replies */
90 /* Try a different server */
91 if (ep->server_af /* ip6 */ )
94 clib_warning ("Server %U failed to resolve '%s'",
96 dm->ip6_name_servers + ep->server_rotor, ep->name);
97 /* Any more servers to try? */
98 if (ep->server_fails > 1 || vec_len (dm->ip6_name_servers) <= 1)
100 /* No, tell the client to go away */
106 if (ep->server_rotor >= vec_len (dm->ip6_name_servers))
107 ep->server_rotor = 0;
109 clib_warning ("Try server %U", format_ip6_address,
110 dm->ip6_name_servers + ep->server_rotor);
111 vnet_dns_send_dns6_request
112 (dm, ep, dm->ip6_name_servers + ep->server_rotor);
117 clib_warning ("Server %U failed to resolve '%s'",
119 dm->ip4_name_servers + ep->server_rotor, ep->name);
121 if (ep->server_fails > 1 || vec_len (dm->ip4_name_servers) <= 1)
123 /* No, tell the client to go away */
129 if (ep->server_rotor >= vec_len (dm->ip4_name_servers))
130 ep->server_rotor = 0;
132 clib_warning ("Try server %U", format_ip4_address,
133 dm->ip4_name_servers + ep->server_rotor);
134 vnet_dns_send_dns4_request
135 (dm, ep, dm->ip4_name_servers + ep->server_rotor);
137 dns_cache_unlock (dm);
142 /* Save the response */
143 ep->dns_response = reply;
146 * Pick a sensible default cache entry expiration time.
147 * We don't play the 10-second timeout game.
149 ep->expiration_time = now + 600.0;
152 clib_warning ("resolving '%s', was %s valid",
153 ep->name, (ep->flags & DNS_CACHE_ENTRY_FLAG_VALID) ?
156 * The world is a mess. A single DNS request sent to e.g. 8.8.8.8
157 * may yield multiple, subtly different responses - all with the same
158 * DNS protocol-level ID.
160 * Last response wins in terms of what ends up in the cache.
161 * First response wins in terms of the response sent to the client.
164 /* Strong hint that we may not find a pending resolution entry */
165 entry_was_valid = (ep->flags & DNS_CACHE_ENTRY_FLAG_VALID) ? 1 : 0;
167 if (vec_len (ep->dns_response))
168 ep->flags |= DNS_CACHE_ENTRY_FLAG_VALID;
170 /* Most likely, send 1 message */
171 for (i = 0; i < vec_len (ep->pending_requests); i++)
173 vl_api_registration_t *regp;
175 pr = vec_elt_at_index (ep->pending_requests, i);
177 switch (pr->request_type)
179 case DNS_API_PENDING_NAME_TO_IP:
181 vl_api_dns_resolve_name_reply_t *rmp;
182 regp = vl_api_client_index_to_registration (pr->client_index);
186 rmp = vl_msg_api_alloc (sizeof (*rmp));
188 clib_host_to_net_u16 (VL_API_DNS_RESOLVE_NAME_REPLY
190 rmp->context = pr->client_context;
192 rv = vnet_dns_response_to_reply (ep->dns_response, rmp, &min_ttl);
194 ep->expiration_time = now + min_ttl;
195 rmp->retval = clib_host_to_net_u32 (rv);
196 vl_api_send_msg (regp, (u8 *) rmp);
200 case DNS_API_PENDING_IP_TO_NAME:
202 vl_api_dns_resolve_ip_reply_t *rmp;
204 regp = vl_api_client_index_to_registration (pr->client_index);
208 rmp = vl_msg_api_alloc (sizeof (*rmp));
210 clib_host_to_net_u16 (VL_API_DNS_RESOLVE_IP_REPLY
212 rmp->context = pr->client_context;
214 rv = vnet_dns_response_to_name (ep->dns_response, rmp, &min_ttl);
216 ep->expiration_time = now + min_ttl;
217 rmp->retval = clib_host_to_net_u32 (rv);
218 vl_api_send_msg (regp, (u8 *) rmp);
222 case DNS_PEER_PENDING_IP_TO_NAME:
223 case DNS_PEER_PENDING_NAME_TO_IP:
225 vnet_send_dns6_reply (dm, pr, ep, 0 /* allocate a buffer */ );
227 vnet_send_dns4_reply (dm, pr, ep, 0 /* allocate a buffer */ );
230 clib_warning ("request type %d unknown", pr->request_type);
234 vec_free (ep->pending_requests);
237 for (i = 0; i < vec_len (dm->unresolved_entries); i++)
239 if (dm->unresolved_entries[i] == pool_index)
241 vec_delete (dm->unresolved_entries, 1, i);
246 /* See multiple response comment above... */
247 if (remove_count == 0)
249 u32 error_code = entry_was_valid ? DNS46_REPLY_ERROR_MULTIPLE_REPLY :
250 DNS46_REPLY_ERROR_NO_UNRESOLVED_ENTRY;
252 vlib_node_increment_counter (vm, dns46_reply_node.index, error_code, 1);
253 dns_cache_unlock (dm);
257 /* Deal with bogus names, server issues, etc. */
261 case DNS_RCODE_NO_ERROR:
264 case DNS_RCODE_SERVER_FAILURE:
265 case DNS_RCODE_NOT_IMPLEMENTED:
266 case DNS_RCODE_REFUSED:
267 if (ep->server_af == 0)
268 clib_warning ("name server %U can't resolve '%s'",
270 dm->ip4_name_servers + ep->server_rotor, ep->name);
272 clib_warning ("name server %U can't resolve '%s'",
274 dm->ip6_name_servers + ep->server_rotor, ep->name);
276 case DNS_RCODE_NAME_ERROR:
277 case DNS_RCODE_FORMAT_ERROR:
278 /* remove trash from the cache... */
279 vnet_dns_delete_entry_by_index_nolock (dm, ep - dm->entries);
284 dns_cache_unlock (dm);
289 retry_scan (dns_main_t * dm, f64 now)
292 dns_cache_entry_t *ep;
294 for (i = 0; i < vec_len (dm->unresolved_entries); i++)
296 dns_cache_lock (dm, 11);
297 ep = pool_elt_at_index (dm->entries, dm->unresolved_entries[i]);
299 ASSERT ((ep->flags & DNS_CACHE_ENTRY_FLAG_VALID) == 0);
300 vnet_send_dns_request (dm, ep);
301 dns_cache_unlock (dm);
306 dns_resolver_process (vlib_main_t * vm,
307 vlib_node_runtime_t * rt, vlib_frame_t * f)
309 dns_main_t *dm = &dns_main;
311 f64 timeout = 1000.0;
312 uword *event_data = 0;
318 vlib_process_wait_for_event_or_clock (vm, timeout);
320 now = vlib_time_now (vm);
322 event_type = vlib_process_get_events (vm, (uword **) & event_data);
326 /* Send one of these when a resolution is pending */
327 case DNS_RESOLVER_EVENT_PENDING:
331 case DNS_RESOLVER_EVENT_RESOLVED:
332 for (i = 0; i < vec_len (event_data); i++)
333 resolve_event (dm, now, (u8 *) event_data[i]);
336 case ~0: /* timeout */
337 retry_scan (dm, now);
340 vec_reset_length (event_data);
342 /* No work? Back to slow timeout mode... */
343 if (vec_len (dm->unresolved_entries) == 0)
346 return 0; /* or not */
350 vnet_dns_create_resolver_process (dns_main_t * dm)
352 /* Already created the resolver process? */
353 if (dm->resolver_process_node_index > 0)
356 /* No, create it now and make a note of the node index */
357 dm->resolver_process_node_index = vlib_process_create
358 (dm->vlib_main, "dns-resolver-process",
359 dns_resolver_process, 16 /* log2_n_stack_bytes */ );
363 * fd.io coding-style-patch-verification: ON
366 * eval: (c-set-style "gnu")