1 #ifndef HEADER_CURL_ASYN_H 2 #define HEADER_CURL_ASYN_H 3 /*************************************************************************** 4 * _ _ ____ _ 5 * Project ___| | | | _ \| | 6 * / __| | | | |_) | | 7 * | (__| |_| | _ <| |___ 8 * \___|\___/|_| \_\_____| 9 * 10 * Copyright (C) 1998 - 2011, 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 http://curl.haxx.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 ***************************************************************************/ 24 25 #include "curl_setup.h" 26 #include "curl_addrinfo.h" 27 28 struct addrinfo; 29 struct hostent; 30 struct SessionHandle; 31 struct connectdata; 32 struct Curl_dns_entry; 33 34 /* 35 * This header defines all functions in the internal asynch resolver interface. 36 * All asynch resolvers need to provide these functions. 37 * asyn-ares.c and asyn-thread.c are the current implementations of asynch 38 * resolver backends. 39 */ 40 41 /* 42 * Curl_resolver_global_init() 43 * 44 * Called from curl_global_init() to initialize global resolver environment. 45 * Returning anything else than CURLE_OK fails curl_global_init(). 46 */ 47 int Curl_resolver_global_init(void); 48 49 /* 50 * Curl_resolver_global_cleanup() 51 * Called from curl_global_cleanup() to destroy global resolver environment. 52 */ 53 void Curl_resolver_global_cleanup(void); 54 55 /* 56 * Curl_resolver_init() 57 * Called from curl_easy_init() -> Curl_open() to initialize resolver 58 * URL-state specific environment ('resolver' member of the UrlState 59 * structure). Should fill the passed pointer by the initialized handler. 60 * Returning anything else than CURLE_OK fails curl_easy_init() with the 61 * correspondent code. 62 */ 63 CURLcode Curl_resolver_init(void **resolver); 64 65 /* 66 * Curl_resolver_cleanup() 67 * Called from curl_easy_cleanup() -> Curl_close() to cleanup resolver 68 * URL-state specific environment ('resolver' member of the UrlState 69 * structure). Should destroy the handler and free all resources connected to 70 * it. 71 */ 72 void Curl_resolver_cleanup(void *resolver); 73 74 /* 75 * Curl_resolver_duphandle() 76 * Called from curl_easy_duphandle() to duplicate resolver URL-state specific 77 * environment ('resolver' member of the UrlState structure). Should 78 * duplicate the 'from' handle and pass the resulting handle to the 'to' 79 * pointer. Returning anything else than CURLE_OK causes failed 80 * curl_easy_duphandle() call. 81 */ 82 int Curl_resolver_duphandle(void **to, void *from); 83 84 /* 85 * Curl_resolver_cancel(). 86 * 87 * It is called from inside other functions to cancel currently performing 88 * resolver request. Should also free any temporary resources allocated to 89 * perform a request. 90 */ 91 void Curl_resolver_cancel(struct connectdata *conn); 92 93 /* Curl_resolver_getsock() 94 * 95 * This function is called from the multi_getsock() function. 'sock' is a 96 * pointer to an array to hold the file descriptors, with 'numsock' being the 97 * size of that array (in number of entries). This function is supposed to 98 * return bitmask indicating what file descriptors (referring to array indexes 99 * in the 'sock' array) to wait for, read/write. 100 */ 101 int Curl_resolver_getsock(struct connectdata *conn, curl_socket_t *sock, 102 int numsocks); 103 104 /* 105 * Curl_resolver_is_resolved() 106 * 107 * Called repeatedly to check if a previous name resolve request has 108 * completed. It should also make sure to time-out if the operation seems to 109 * take too long. 110 * 111 * Returns normal CURLcode errors. 112 */ 113 CURLcode Curl_resolver_is_resolved(struct connectdata *conn, 114 struct Curl_dns_entry **dns); 115 116 /* 117 * Curl_resolver_wait_resolv() 118 * 119 * waits for a resolve to finish. This function should be avoided since using 120 * this risk getting the multi interface to "hang". 121 * 122 * If 'entry' is non-NULL, make it point to the resolved dns entry 123 * 124 * Returns CURLE_COULDNT_RESOLVE_HOST if the host was not resolved, and 125 * CURLE_OPERATION_TIMEDOUT if a time-out occurred. 126 127 */ 128 CURLcode Curl_resolver_wait_resolv(struct connectdata *conn, 129 struct Curl_dns_entry **dnsentry); 130 131 /* 132 * Curl_resolver_getaddrinfo() - when using this resolver 133 * 134 * Returns name information about the given hostname and port number. If 135 * successful, the 'hostent' is returned and the forth argument will point to 136 * memory we need to free after use. That memory *MUST* be freed with 137 * Curl_freeaddrinfo(), nothing else. 138 * 139 * Each resolver backend must of course make sure to return data in the 140 * correct format to comply with this. 141 */ 142 Curl_addrinfo *Curl_resolver_getaddrinfo(struct connectdata *conn, 143 const char *hostname, 144 int port, 145 int *waitp); 146 147 #ifndef CURLRES_ASYNCH 148 /* convert these functions if an asynch resolver isn't used */ 149 #define Curl_resolver_cancel(x) Curl_nop_stmt 150 #define Curl_resolver_is_resolved(x,y) CURLE_COULDNT_RESOLVE_HOST 151 #define Curl_resolver_wait_resolv(x,y) CURLE_COULDNT_RESOLVE_HOST 152 #define Curl_resolver_getsock(x,y,z) 0 153 #define Curl_resolver_duphandle(x,y) CURLE_OK 154 #define Curl_resolver_init(x) CURLE_OK 155 #define Curl_resolver_global_init() CURLE_OK 156 #define Curl_resolver_global_cleanup() Curl_nop_stmt 157 #define Curl_resolver_cleanup(x) Curl_nop_stmt 158 #endif 159 160 #ifdef CURLRES_ASYNCH 161 #define Curl_resolver_asynch() 1 162 #else 163 #define Curl_resolver_asynch() 0 164 #endif 165 166 167 /********** end of generic resolver interface functions *****************/ 168 #endif /* HEADER_CURL_ASYN_H */ 169