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libwebsockets/include/libwebsockets/lws-async-dns.h
2019-10-12 12:41:14 +01:00

85 lines
3.2 KiB
C

/*
* libwebsockets - small server side websockets and web server implementation
*
* Copyright (C) 2010 - 2019 Andy Green <andy@warmcat.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#if defined(LWS_WITH_UDP)
typedef enum dns_query_type {
LWS_ADNS_RECORD_A = 0x01,
LWS_ADNS_RECORD_CNAME = 0x05,
LWS_ADNS_RECORD_MX = 0x0f,
LWS_ADNS_RECORD_AAAA = 0x1c,
} adns_query_type_t;
typedef enum {
LADNS_RET_FAILED_WSI_CLOSED = -4,
LADNS_RET_NXDOMAIN = -3,
LADNS_RET_TIMEDOUT = -2,
LADNS_RET_FAILED = -1,
LADNS_RET_FOUND,
LADNS_RET_CONTINUING
} lws_async_dns_retcode_t;
typedef struct lws * (*lws_async_dns_cb_t)(struct lws *wsi, const char *ads,
const struct addrinfo *result, int n,
void *opaque);
/**
* lws_async_dns_query() - perform a dns lookup using async dns
*
* \param context: the lws_context
* \param tsi: thread service index (usually 0)
* \param name: DNS name to look up
* \param qtype: type of query (A, AAAA etc)
* \param cb: query completion callback
* \param wsi: wsi if the query is related to one
*
* Starts an asynchronous DNS lookup, on completion the \p cb callback will
* be called.
*
* The reference count on the cached object is incremented for every callback
* that was called with the cached addrinfo results.
*
* The cached object can't be evicted until the reference count reaches zero...
* use lws_async_dns_freeaddrinfo() to indicate you're finsihed with the
* results for each callback that happened with them.
*/
LWS_VISIBLE LWS_EXTERN lws_async_dns_retcode_t
lws_async_dns_query(struct lws_context *context, int tsi, const char *name,
adns_query_type_t qtype, lws_async_dns_cb_t cb,
struct lws *wsi, void *opaque);
/**
* lws_async_dns_freeaddrinfo() - decrement refcount on cached addrinfo results
*
* \param pai: a pointert to a pointer to first addrinfo returned as result in the callback
*
* Decrements the cache object's reference count. When it reaches zero, the
* cached object may be reaped subject to LRU rules.
*
* The pointer to the first addrinfo give in the argument is set to NULL.
*/
LWS_VISIBLE LWS_EXTERN void
lws_async_dns_freeaddrinfo(const struct addrinfo **ai);
#endif