xref: /freebsd/contrib/unbound/services/cache/dns.h (revision 52c2bb75163559a6e2866ad374a7de67a4ea1273)
1 /*
2  * services/cache/dns.h - Cache services for DNS using msg and rrset caches.
3  *
4  * Copyright (c) 2007, NLnet Labs. All rights reserved.
5  *
6  * This software is open source.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * Redistributions of source code must retain the above copyright notice,
13  * this list of conditions and the following disclaimer.
14  *
15  * Redistributions in binary form must reproduce the above copyright notice,
16  * this list of conditions and the following disclaimer in the documentation
17  * and/or other materials provided with the distribution.
18  *
19  * Neither the name of the NLNET LABS nor the names of its contributors may
20  * be used to endorse or promote products derived from this software without
21  * specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
24  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
25  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
26  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
27  * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
29  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
30  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
31  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
32  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
33  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34  */
35 
36 /**
37  * \file
38  *
39  * This file contains the DNS cache.
40  */
41 
42 #ifndef SERVICES_CACHE_DNS_H
43 #define SERVICES_CACHE_DNS_H
44 #include "util/storage/lruhash.h"
45 #include "util/data/msgreply.h"
46 struct module_env;
47 struct query_info;
48 struct reply_info;
49 struct regional;
50 struct delegpt;
51 
52 /** Flags to control behavior of dns_cache_store() and dns_cache_store_msg().
53  *  Must be an unsigned 32-bit value larger than 0xffff */
54 
55 /** Allow caching a DNS message with a zero TTL. */
56 #define DNSCACHE_STORE_ZEROTTL 0x100000
57 
58 /**
59  * Region allocated message reply
60  */
61 struct dns_msg {
62 	/** query info */
63 	struct query_info qinfo;
64 	/** reply info - ptr to packed repinfo structure */
65 	struct reply_info *rep;
66 };
67 
68 /**
69  * Allocate a dns_msg with malloc/alloc structure and store in dns cache.
70  *
71  * @param env: environment, with alloc structure and dns cache.
72  * @param qinf: query info, the query for which answer is stored.
73  * 	this is allocated in a region, and will be copied to malloc area
74  * 	before insertion.
75  * @param rep: reply in dns_msg from dns_alloc_msg for example.
76  * 	this is allocated in a region, and will be copied to malloc area
77  * 	before insertion.
78  * @param is_referral: If true, then the given message to be stored is a
79  *      referral. The cache implementation may use this as a hint.
80  *      It will store only the RRsets, not the message.
81  * @param leeway: TTL value, if not 0, other rrsets are considered expired
82  *	that many seconds before actual TTL expiry.
83  * @param pside: if true, information came from a server which was fetched
84  * 	from the parentside of the zonecut.  This means that the type NS
85  * 	can be updated to full TTL even in prefetch situations.
86  * @param region: region to allocate better entries from cache into.
87  *   (used when is_referral is false).
88  * @param flags: flags with BIT_CD for AAAA queries in dns64 translation.
89  *   The higher 16 bits are used internally to customize the cache policy.
90  *   (See DNSCACHE_STORE_xxx flags).
91  * @return 0 on alloc error (out of memory).
92  */
93 int dns_cache_store(struct module_env* env, struct query_info* qinf,
94         struct reply_info* rep, int is_referral, time_t leeway, int pside,
95 	struct regional* region, uint32_t flags);
96 
97 /**
98  * Store message in the cache. Stores in message cache and rrset cache.
99  * Both qinfo and rep should be malloced and are put in the cache.
100  * They should not be used after this call, as they are then in shared cache.
101  * Does not return errors, they are logged and only lead to less cache.
102  *
103  * @param env: module environment with the DNS cache.
104  * @param qinfo: query info
105  * @param hash: hash over qinfo.
106  * @param rep: reply info, together with qinfo makes up the message.
107  *	Adjusts the reply info TTLs to absolute time.
108  * @param leeway: TTL value, if not 0, other rrsets are considered expired
109  *	that many seconds before actual TTL expiry.
110  * @param pside: if true, information came from a server which was fetched
111  * 	from the parentside of the zonecut.  This means that the type NS
112  * 	can be updated to full TTL even in prefetch situations.
113  * @param qrep: message that can be altered with better rrs from cache.
114  * @param flags: customization flags for the cache policy.
115  * @param region: to allocate into for qmsg.
116  */
117 void dns_cache_store_msg(struct module_env* env, struct query_info* qinfo,
118 	hashvalue_type hash, struct reply_info* rep, time_t leeway, int pside,
119 	struct reply_info* qrep, uint32_t flags, struct regional* region);
120 
121 /**
122  * Find a delegation from the cache.
123  * @param env: module environment with the DNS cache.
124  * @param qname: query name.
125  * @param qnamelen: length of qname.
126  * @param qtype: query type.
127  * @param qclass: query class.
128  * @param region: where to allocate result delegation.
129  * @param msg: if not NULL, delegation message is returned here, synthesized
130  *	from the cache.
131  * @param timenow: the time now, for checking if TTL on cache entries is OK.
132  * @return new delegation or NULL on error or if not found in cache.
133  */
134 struct delegpt* dns_cache_find_delegation(struct module_env* env,
135 	uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass,
136 	struct regional* region, struct dns_msg** msg, time_t timenow);
137 
138 /**
139  * generate dns_msg from cached message
140  * @param env: module environment with the DNS cache. NULL if the LRU from cache
141  * 	does not need to be touched.
142  * @param q: query info, contains qname that will make up the dns message.
143  * @param r: reply info that, together with qname, will make up the dns message.
144  * @param region: where to allocate dns message.
145  * @param now: the time now, for check if TTL on cache entry is ok.
146  * @param scratch: where to allocate temporary data.
147  * */
148 struct dns_msg* tomsg(struct module_env* env, struct query_info* q,
149 	struct reply_info* r, struct regional* region, time_t now,
150 	struct regional* scratch);
151 
152 /**
153  * Find cached message
154  * @param env: module environment with the DNS cache.
155  * @param qname: query name.
156  * @param qnamelen: length of qname.
157  * @param qtype: query type.
158  * @param qclass: query class.
159  * @param flags: flags with BIT_CD for AAAA queries in dns64 translation.
160  * @param region: where to allocate result.
161  * @param scratch: where to allocate temporary data.
162  * @param no_partial: if true, only complete messages and not a partial
163  *   one (with only the start of the CNAME chain and not the rest).
164  * @return new response message (alloced in region, rrsets do not have IDs).
165  * 	or NULL on error or if not found in cache.
166  *	TTLs are made relative to the current time.
167  */
168 struct dns_msg* dns_cache_lookup(struct module_env* env,
169 	uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass,
170 	uint16_t flags, struct regional* region, struct regional* scratch,
171 	int no_partial);
172 
173 /**
174  * find and add A and AAAA records for missing nameservers in delegpt
175  * @param env: module environment with rrset cache
176  * @param qclass: which class to look in.
177  * @param region: where to store new dp info.
178  * @param dp: delegation point to fill missing entries.
179  * @return false on alloc failure.
180  */
181 int cache_fill_missing(struct module_env* env, uint16_t qclass,
182 	struct regional* region, struct delegpt* dp);
183 
184 /**
185  * Utility, create new, unpacked data structure for cache response.
186  * QR bit set, no AA. Query set as indicated. Space for number of rrsets.
187  * @param qname: query section name
188  * @param qnamelen: len of qname
189  * @param qtype: query section type
190  * @param qclass: query section class
191  * @param region: where to alloc.
192  * @param capacity: number of rrsets space to create in the array.
193  * @return new dns_msg struct or NULL on mem fail.
194  */
195 struct dns_msg* dns_msg_create(uint8_t* qname, size_t qnamelen, uint16_t qtype,
196 	uint16_t qclass, struct regional* region, size_t capacity);
197 
198 /**
199  * Add rrset to authority section in unpacked dns_msg message. Must have enough
200  * space left, does not grow the array.
201  * @param msg: msg to put it in.
202  * @param region: region to alloc in
203  * @param rrset: to add in authority section
204  * @param now: now.
205  * @return true if worked, false on fail
206  */
207 int dns_msg_authadd(struct dns_msg* msg, struct regional* region,
208 	struct ub_packed_rrset_key* rrset, time_t now);
209 
210 /**
211  * Add rrset to authority section in unpacked dns_msg message. Must have enough
212  * space left, does not grow the array.
213  * @param msg: msg to put it in.
214  * @param region: region to alloc in
215  * @param rrset: to add in authority section
216  * @param now: now.
217  * @return true if worked, false on fail
218  */
219 int dns_msg_ansadd(struct dns_msg* msg, struct regional* region,
220 	struct ub_packed_rrset_key* rrset, time_t now);
221 
222 /**
223  * Adjust the prefetch_ttl for a cached message.  This adds a value to the
224  * prefetch ttl - postponing the time when it will be prefetched for future
225  * incoming queries.
226  * @param env: module environment with caches and time.
227  * @param qinfo: query info for the query that needs adjustment.
228  * @param adjust: time in seconds to add to the prefetch_leeway.
229  * @param flags: flags with BIT_CD for AAAA queries in dns64 translation.
230  * @return false if not in cache. true if added.
231  */
232 int dns_cache_prefetch_adjust(struct module_env* env, struct query_info* qinfo,
233         time_t adjust, uint16_t flags);
234 
235 /** lookup message in message cache
236  * the returned nonNULL entry is locked and has to be unlocked by the caller */
237 struct msgreply_entry* msg_cache_lookup(struct module_env* env,
238 	uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass,
239 	uint16_t flags, time_t now, int wr);
240 
241 /**
242  * Remove entry from the message cache.  For unwanted entries.
243  * @param env: with message cache.
244  * @param qname: query name, in wireformat
245  * @param qnamelen: length of qname, including terminating 0.
246  * @param qtype: query type, host order.
247  * @param qclass: query class, host order.
248  * @param flags: flags
249  */
250 void msg_cache_remove(struct module_env* env, uint8_t* qname, size_t qnamelen,
251 	uint16_t qtype, uint16_t qclass, uint16_t flags);
252 
253 #endif /* SERVICES_CACHE_DNS_H */
254