1/*
2 * libwebsockets - small server side websockets and web server implementation
3 *
4 * Copyright (C) 2010 - 2019 Andy Green <andy@warmcat.com>
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to
8 * deal in the Software without restriction, including without limitation the
9 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
10 * sell copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
22 * IN THE SOFTWARE.
23 */
24
25#if defined(LWS_WITH_UDP)
26
27typedef enum dns_query_type {
28 LWS_ADNS_RECORD_A = 0x01,
29 LWS_ADNS_RECORD_CNAME = 0x05,
30 LWS_ADNS_RECORD_MX = 0x0f,
31 LWS_ADNS_RECORD_AAAA = 0x1c,
32} adns_query_type_t;
33
34typedef enum {
35 LADNS_RET_FAILED_WSI_CLOSED = -4,
36 LADNS_RET_NXDOMAIN = -3,
37 LADNS_RET_TIMEDOUT = -2,
38 LADNS_RET_FAILED = -1,
39 LADNS_RET_FOUND,
40 LADNS_RET_CONTINUING
41} lws_async_dns_retcode_t;
42
43struct addrinfo;
44
45typedef struct lws * (*lws_async_dns_cb_t)(struct lws *wsi, const char *ads,
46 const struct addrinfo *result, int n, void *opaque);
47
48/**
49 * lws_async_dns_query() - perform a dns lookup using async dns
50 *
51 * \param context: the lws_context
52 * \param tsi: thread service index (usually 0)
53 * \param name: DNS name to look up
54 * \param qtype: type of query (A, AAAA etc)
55 * \param cb: query completion callback
56 * \param wsi: wsi if the query is related to one
57 *
58 * Starts an asynchronous DNS lookup, on completion the \p cb callback will
59 * be called.
60 *
61 * The reference count on the cached object is incremented for every callback
62 * that was called with the cached addrinfo results.
63 *
64 * The cached object can't be evicted until the reference count reaches zero...
65 * use lws_async_dns_freeaddrinfo() to indicate you're finsihed with the
66 * results for each callback that happened with them.
67 */
68LWS_VISIBLE LWS_EXTERN lws_async_dns_retcode_t
69lws_async_dns_query(struct lws_context *context, int tsi, const char *name,
70 adns_query_type_t qtype, lws_async_dns_cb_t cb,
71 struct lws *wsi, void *opaque);
72
73/**
74 * lws_async_dns_freeaddrinfo() - decrement refcount on cached addrinfo results
75 *
76 * \param pai: a pointert to a pointer to first addrinfo returned as result in the callback
77 *
78 * Decrements the cache object's reference count. When it reaches zero, the
79 * cached object may be reaped subject to LRU rules.
80 *
81 * The pointer to the first addrinfo give in the argument is set to NULL.
82 */
83LWS_VISIBLE LWS_EXTERN void
84lws_async_dns_freeaddrinfo(const struct addrinfo **ai);
85
86#endif
87