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 27 typedef 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 34 typedef 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 43 typedef struct lws * (*lws_async_dns_cb_t)(struct lws *wsi, const char *ads, 44 const struct addrinfo *result, int n, 45 void *opaque); 46 47 /** 48 * lws_async_dns_query() - perform a dns lookup using async dns 49 * 50 * \param context: the lws_context 51 * \param tsi: thread service index (usually 0) 52 * \param name: DNS name to look up 53 * \param qtype: type of query (A, AAAA etc) 54 * \param cb: query completion callback 55 * \param wsi: wsi if the query is related to one 56 * 57 * Starts an asynchronous DNS lookup, on completion the \p cb callback will 58 * be called. 59 * 60 * The reference count on the cached object is incremented for every callback 61 * that was called with the cached addrinfo results. 62 * 63 * The cached object can't be evicted until the reference count reaches zero... 64 * use lws_async_dns_freeaddrinfo() to indicate you're finsihed with the 65 * results for each callback that happened with them. 66 */ 67 LWS_VISIBLE LWS_EXTERN lws_async_dns_retcode_t 68 lws_async_dns_query(struct lws_context *context, int tsi, const char *name, 69 adns_query_type_t qtype, lws_async_dns_cb_t cb, 70 struct lws *wsi, void *opaque); 71 72 /** 73 * lws_async_dns_freeaddrinfo() - decrement refcount on cached addrinfo results 74 * 75 * \param pai: a pointert to a pointer to first addrinfo returned as result in the callback 76 * 77 * Decrements the cache object's reference count. When it reaches zero, the 78 * cached object may be reaped subject to LRU rules. 79 * 80 * The pointer to the first addrinfo give in the argument is set to NULL. 81 */ 82 LWS_VISIBLE LWS_EXTERN void 83 lws_async_dns_freeaddrinfo(const struct addrinfo **ai); 84 85 #endif 86