1 #ifndef HEADER_CURL_ASYN_H 2 #define HEADER_CURL_ASYN_H 3 /*************************************************************************** 4 * _ _ ____ _ 5 * Project ___| | | | _ \| | 6 * / __| | | | |_) | | 7 * | (__| |_| | _ <| |___ 8 * \___|\___/|_| \_\_____| 9 * 10 * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. 11 * 12 * This software is licensed as described in the file COPYING, which 13 * you should have received as part of this distribution. The terms 14 * are also available at https://curl.se/docs/copyright.html. 15 * 16 * You may opt to use, copy, modify, merge, publish, distribute and/or sell 17 * copies of the Software, and permit persons to whom the Software is 18 * furnished to do so, under the terms of the COPYING file. 19 * 20 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY 21 * KIND, either express or implied. 22 * 23 * SPDX-License-Identifier: curl 24 * 25 ***************************************************************************/ 26 27 #include "curl_setup.h" 28 #include "curl_addrinfo.h" 29 30 struct addrinfo; 31 struct hostent; 32 struct Curl_easy; 33 struct connectdata; 34 struct Curl_dns_entry; 35 36 /* 37 * This header defines all functions in the internal asynch resolver interface. 38 * All asynch resolvers need to provide these functions. 39 * asyn-ares.c and asyn-thread.c are the current implementations of asynch 40 * resolver backends. 41 */ 42 43 /* 44 * Curl_resolver_global_init() 45 * 46 * Called from curl_global_init() to initialize global resolver environment. 47 * Returning anything else than CURLE_OK fails curl_global_init(). 48 */ 49 int Curl_resolver_global_init(void); 50 51 /* 52 * Curl_resolver_global_cleanup() 53 * Called from curl_global_cleanup() to destroy global resolver environment. 54 */ 55 void Curl_resolver_global_cleanup(void); 56 57 /* 58 * Curl_resolver_init() 59 * Called from curl_easy_init() -> Curl_open() to initialize resolver 60 * URL-state specific environment ('resolver' member of the UrlState 61 * structure). Should fill the passed pointer by the initialized handler. 62 * Returning anything else than CURLE_OK fails curl_easy_init() with the 63 * correspondent code. 64 */ 65 CURLcode Curl_resolver_init(struct Curl_easy *easy, void **resolver); 66 67 /* 68 * Curl_resolver_cleanup() 69 * Called from curl_easy_cleanup() -> Curl_close() to cleanup resolver 70 * URL-state specific environment ('resolver' member of the UrlState 71 * structure). Should destroy the handler and free all resources connected to 72 * it. 73 */ 74 void Curl_resolver_cleanup(void *resolver); 75 76 /* 77 * Curl_resolver_duphandle() 78 * Called from curl_easy_duphandle() to duplicate resolver URL-state specific 79 * environment ('resolver' member of the UrlState structure). Should 80 * duplicate the 'from' handle and pass the resulting handle to the 'to' 81 * pointer. Returning anything else than CURLE_OK causes failed 82 * curl_easy_duphandle() call. 83 */ 84 CURLcode Curl_resolver_duphandle(struct Curl_easy *easy, void **to, 85 void *from); 86 87 /* 88 * Curl_resolver_cancel(). 89 * 90 * It is called from inside other functions to cancel currently performing 91 * resolver request. Should also free any temporary resources allocated to 92 * perform a request. This never waits for resolver threads to complete. 93 * 94 * It is safe to call this when conn is in any state. 95 */ 96 void Curl_resolver_cancel(struct Curl_easy *data); 97 98 /* 99 * Curl_resolver_kill(). 100 * 101 * This acts like Curl_resolver_cancel() except it will block until any threads 102 * associated with the resolver are complete. This never blocks for resolvers 103 * that do not use threads. This is intended to be the "last chance" function 104 * that cleans up an in-progress resolver completely (before its owner is about 105 * to die). 106 * 107 * It is safe to call this when conn is in any state. 108 */ 109 void Curl_resolver_kill(struct Curl_easy *data); 110 111 /* Curl_resolver_getsock() 112 * 113 * This function is called from the multi_getsock() function. 'sock' is a 114 * pointer to an array to hold the file descriptors, with 'numsock' being the 115 * size of that array (in number of entries). This function is supposed to 116 * return bitmask indicating what file descriptors (referring to array indexes 117 * in the 'sock' array) to wait for, read/write. 118 */ 119 int Curl_resolver_getsock(struct Curl_easy *data, curl_socket_t *sock); 120 121 /* 122 * Curl_resolver_is_resolved() 123 * 124 * Called repeatedly to check if a previous name resolve request has 125 * completed. It should also make sure to time-out if the operation seems to 126 * take too long. 127 * 128 * Returns normal CURLcode errors. 129 */ 130 CURLcode Curl_resolver_is_resolved(struct Curl_easy *data, 131 struct Curl_dns_entry **dns); 132 133 /* 134 * Curl_resolver_wait_resolv() 135 * 136 * Waits for a resolve to finish. This function should be avoided since using 137 * this risk getting the multi interface to "hang". 138 * 139 * If 'entry' is non-NULL, make it point to the resolved dns entry 140 * 141 * Returns CURLE_COULDNT_RESOLVE_HOST if the host was not resolved, 142 * CURLE_OPERATION_TIMEDOUT if a time-out occurred, or other errors. 143 */ 144 CURLcode Curl_resolver_wait_resolv(struct Curl_easy *data, 145 struct Curl_dns_entry **dnsentry); 146 147 /* 148 * Curl_resolver_getaddrinfo() - when using this resolver 149 * 150 * Returns name information about the given hostname and port number. If 151 * successful, the 'hostent' is returned and the fourth argument will point to 152 * memory we need to free after use. That memory *MUST* be freed with 153 * Curl_freeaddrinfo(), nothing else. 154 * 155 * Each resolver backend must of course make sure to return data in the 156 * correct format to comply with this. 157 */ 158 struct Curl_addrinfo *Curl_resolver_getaddrinfo(struct Curl_easy *data, 159 const char *hostname, 160 int port, 161 int *waitp); 162 163 #ifndef CURLRES_ASYNCH 164 /* convert these functions if an asynch resolver isn't used */ 165 #define Curl_resolver_cancel(x) Curl_nop_stmt 166 #define Curl_resolver_kill(x) Curl_nop_stmt 167 #define Curl_resolver_is_resolved(x,y) CURLE_COULDNT_RESOLVE_HOST 168 #define Curl_resolver_wait_resolv(x,y) CURLE_COULDNT_RESOLVE_HOST 169 #define Curl_resolver_duphandle(x,y,z) CURLE_OK 170 #define Curl_resolver_init(x,y) CURLE_OK 171 #define Curl_resolver_global_init() CURLE_OK 172 #define Curl_resolver_global_cleanup() Curl_nop_stmt 173 #define Curl_resolver_cleanup(x) Curl_nop_stmt 174 #endif 175 176 #ifdef CURLRES_ASYNCH 177 #define Curl_resolver_asynch() 1 178 #else 179 #define Curl_resolver_asynch() 0 180 #endif 181 182 183 /********** end of generic resolver interface functions *****************/ 184 #endif /* HEADER_CURL_ASYN_H */ 185
