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    1: #ifndef HEADER_CURL_ASYN_H
    2: #define HEADER_CURL_ASYN_H
    3: /***************************************************************************
    4:  *                                  _   _ ____  _
    5:  *  Project                     ___| | | |  _ \| |
    6:  *                             / __| | | | |_) | |
    7:  *                            | (__| |_| |  _ <| |___
    8:  *                             \___|\___/|_| \_\_____|
    9:  *
   10:  * Copyright (C) 1998 - 2019, 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.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 Curl_easy;
   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(struct Curl_easy *easy, 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: CURLcode Curl_resolver_duphandle(struct Curl_easy *easy, void **to,
   83:                                  void *from);
   84: 
   85: /*
   86:  * Curl_resolver_cancel().
   87:  *
   88:  * It is called from inside other functions to cancel currently performing
   89:  * resolver request. Should also free any temporary resources allocated to
   90:  * perform a request.  This never waits for resolver threads to complete.
   91:  *
   92:  * It is safe to call this when conn is in any state.
   93:  */
   94: void Curl_resolver_cancel(struct connectdata *conn);
   95: 
   96: /*
   97:  * Curl_resolver_kill().
   98:  *
   99:  * This acts like Curl_resolver_cancel() except it will block until any threads
  100:  * associated with the resolver are complete.  This never blocks for resolvers
  101:  * that do not use threads.  This is intended to be the "last chance" function
  102:  * that cleans up an in-progress resolver completely (before its owner is about
  103:  * to die).
  104:  *
  105:  * It is safe to call this when conn is in any state.
  106:  */
  107: void Curl_resolver_kill(struct connectdata *conn);
  108: 
  109: /* Curl_resolver_getsock()
  110:  *
  111:  * This function is called from the multi_getsock() function.  'sock' is a
  112:  * pointer to an array to hold the file descriptors, with 'numsock' being the
  113:  * size of that array (in number of entries). This function is supposed to
  114:  * return bitmask indicating what file descriptors (referring to array indexes
  115:  * in the 'sock' array) to wait for, read/write.
  116:  */
  117: int Curl_resolver_getsock(struct connectdata *conn, curl_socket_t *sock);
  118: 
  119: /*
  120:  * Curl_resolver_is_resolved()
  121:  *
  122:  * Called repeatedly to check if a previous name resolve request has
  123:  * completed. It should also make sure to time-out if the operation seems to
  124:  * take too long.
  125:  *
  126:  * Returns normal CURLcode errors.
  127:  */
  128: CURLcode Curl_resolver_is_resolved(struct connectdata *conn,
  129:                                    struct Curl_dns_entry **dns);
  130: 
  131: /*
  132:  * Curl_resolver_wait_resolv()
  133:  *
  134:  * Waits for a resolve to finish. This function should be avoided since using
  135:  * this risk getting the multi interface to "hang".
  136:  *
  137:  * If 'entry' is non-NULL, make it point to the resolved dns entry
  138:  *
  139:  * Returns CURLE_COULDNT_RESOLVE_HOST if the host was not resolved,
  140:  * CURLE_OPERATION_TIMEDOUT if a time-out occurred, or other errors.
  141:  */
  142: CURLcode Curl_resolver_wait_resolv(struct connectdata *conn,
  143:                                    struct Curl_dns_entry **dnsentry);
  144: 
  145: /*
  146:  * Curl_resolver_getaddrinfo() - when using this resolver
  147:  *
  148:  * Returns name information about the given hostname and port number. If
  149:  * successful, the 'hostent' is returned and the forth argument will point to
  150:  * memory we need to free after use. That memory *MUST* be freed with
  151:  * Curl_freeaddrinfo(), nothing else.
  152:  *
  153:  * Each resolver backend must of course make sure to return data in the
  154:  * correct format to comply with this.
  155:  */
  156: Curl_addrinfo *Curl_resolver_getaddrinfo(struct connectdata *conn,
  157:                                          const char *hostname,
  158:                                          int port,
  159:                                          int *waitp);
  160: 
  161: #ifndef CURLRES_ASYNCH
  162: /* convert these functions if an asynch resolver isn't used */
  163: #define Curl_resolver_cancel(x) Curl_nop_stmt
  164: #define Curl_resolver_kill(x) Curl_nop_stmt
  165: #define Curl_resolver_is_resolved(x,y) CURLE_COULDNT_RESOLVE_HOST
  166: #define Curl_resolver_wait_resolv(x,y) CURLE_COULDNT_RESOLVE_HOST
  167: #define Curl_resolver_getsock(x,y,z) 0
  168: #define Curl_resolver_duphandle(x,y,z) CURLE_OK
  169: #define Curl_resolver_init(x,y) CURLE_OK
  170: #define Curl_resolver_global_init() CURLE_OK
  171: #define Curl_resolver_global_cleanup() Curl_nop_stmt
  172: #define Curl_resolver_cleanup(x) Curl_nop_stmt
  173: #endif
  174: 
  175: #ifdef CURLRES_ASYNCH
  176: #define Curl_resolver_asynch() 1
  177: #else
  178: #define Curl_resolver_asynch() 0
  179: #endif
  180: 
  181: 
  182: /********** end of generic resolver interface functions *****************/
  183: #endif /* HEADER_CURL_ASYN_H */