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    1: /***************************************************************************
    2:  *                                  _   _ ____  _
    3:  *  Project                     ___| | | |  _ \| |
    4:  *                             / __| | | | |_) | |
    5:  *                            | (__| |_| |  _ <| |___
    6:  *                             \___|\___/|_| \_\_____|
    7:  *
    8:  * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
    9:  *
   10:  * This software is licensed as described in the file COPYING, which
   11:  * you should have received as part of this distribution. The terms
   12:  * are also available at https://curl.haxx.se/docs/copyright.html.
   13:  *
   14:  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
   15:  * copies of the Software, and permit persons to whom the Software is
   16:  * furnished to do so, under the terms of the COPYING file.
   17:  *
   18:  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
   19:  * KIND, either express or implied.
   20:  *
   21:  ***************************************************************************/
   22: /* <DESC>
   23:  * An example demonstrating how an application can pass in a custom
   24:  * socket to libcurl to use. This example also handles the connect itself.
   25:  * </DESC>
   26:  */
   27: #include <stdio.h>
   28: #include <string.h>
   29: #include <stdlib.h>
   30: #include <curl/curl.h>
   31: 
   32: #ifdef WIN32
   33: #include <windows.h>
   34: #include <winsock2.h>
   35: #include <ws2tcpip.h>
   36: #define close closesocket
   37: #else
   38: #include <sys/types.h>        /*  socket types              */
   39: #include <sys/socket.h>       /*  socket definitions        */
   40: #include <netinet/in.h>
   41: #include <arpa/inet.h>        /*  inet (3) functions         */
   42: #include <unistd.h>           /*  misc. Unix functions      */
   43: #endif
   44: 
   45: #include <errno.h>
   46: 
   47: /* The IP address and port number to connect to */
   48: #define IPADDR "127.0.0.1"
   49: #define PORTNUM 80
   50: 
   51: #ifndef INADDR_NONE
   52: #define INADDR_NONE 0xffffffff
   53: #endif
   54: 
   55: static size_t write_data(void *ptr, size_t size, size_t nmemb, void *stream)
   56: {
   57:   size_t written = fwrite(ptr, size, nmemb, (FILE *)stream);
   58:   return written;
   59: }
   60: 
   61: static int closecb(void *clientp, curl_socket_t item)
   62: {
   63:   (void)clientp;
   64:   printf("libcurl wants to close %d now\n", (int)item);
   65:   return 0;
   66: }
   67: 
   68: static curl_socket_t opensocket(void *clientp,
   69:                                 curlsocktype purpose,
   70:                                 struct curl_sockaddr *address)
   71: {
   72:   curl_socket_t sockfd;
   73:   (void)purpose;
   74:   (void)address;
   75:   sockfd = *(curl_socket_t *)clientp;
   76:   /* the actual externally set socket is passed in via the OPENSOCKETDATA
   77:      option */
   78:   return sockfd;
   79: }
   80: 
   81: static int sockopt_callback(void *clientp, curl_socket_t curlfd,
   82:                             curlsocktype purpose)
   83: {
   84:   (void)clientp;
   85:   (void)curlfd;
   86:   (void)purpose;
   87:   /* This return code was added in libcurl 7.21.5 */
   88:   return CURL_SOCKOPT_ALREADY_CONNECTED;
   89: }
   90: 
   91: int main(void)
   92: {
   93:   CURL *curl;
   94:   CURLcode res;
   95:   struct sockaddr_in servaddr;  /*  socket address structure  */
   96:   curl_socket_t sockfd;
   97: 
   98: #ifdef WIN32
   99:   WSADATA wsaData;
  100:   int initwsa = WSAStartup(MAKEWORD(2, 0), &wsaData);
  101:   if(initwsa != 0) {
  102:     printf("WSAStartup failed: %d\n", initwsa);
  103:     return 1;
  104:   }
  105: #endif
  106: 
  107:   curl = curl_easy_init();
  108:   if(curl) {
  109:     /*
  110:      * Note that libcurl will internally think that you connect to the host
  111:      * and port that you specify in the URL option.
  112:      */
  113:     curl_easy_setopt(curl, CURLOPT_URL, "http://99.99.99.99:9999");
  114: 
  115:     /* Create the socket "manually" */
  116:     sockfd = socket(AF_INET, SOCK_STREAM, 0);
  117:     if(sockfd == CURL_SOCKET_BAD) {
  118:       printf("Error creating listening socket.\n");
  119:       return 3;
  120:     }
  121: 
  122:     memset(&servaddr, 0, sizeof(servaddr));
  123:     servaddr.sin_family = AF_INET;
  124:     servaddr.sin_port   = htons(PORTNUM);
  125: 
  126:     servaddr.sin_addr.s_addr = inet_addr(IPADDR);
  127:     if(INADDR_NONE == servaddr.sin_addr.s_addr) {
  128:       close(sockfd);
  129:       return 2;
  130:     }
  131: 
  132:     if(connect(sockfd, (struct sockaddr *) &servaddr, sizeof(servaddr)) ==
  133:        -1) {
  134:       close(sockfd);
  135:       printf("client error: connect: %s\n", strerror(errno));
  136:       return 1;
  137:     }
  138: 
  139:     /* no progress meter please */
  140:     curl_easy_setopt(curl, CURLOPT_NOPROGRESS, 1L);
  141: 
  142:     /* send all data to this function  */
  143:     curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
  144: 
  145:     /* call this function to get a socket */
  146:     curl_easy_setopt(curl, CURLOPT_OPENSOCKETFUNCTION, opensocket);
  147:     curl_easy_setopt(curl, CURLOPT_OPENSOCKETDATA, &sockfd);
  148: 
  149:     /* call this function to close sockets */
  150:     curl_easy_setopt(curl, CURLOPT_CLOSESOCKETFUNCTION, closecb);
  151:     curl_easy_setopt(curl, CURLOPT_CLOSESOCKETDATA, &sockfd);
  152: 
  153:     /* call this function to set options for the socket */
  154:     curl_easy_setopt(curl, CURLOPT_SOCKOPTFUNCTION, sockopt_callback);
  155: 
  156:     curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);
  157: 
  158:     res = curl_easy_perform(curl);
  159: 
  160:     curl_easy_cleanup(curl);
  161: 
  162:     close(sockfd);
  163: 
  164:     if(res) {
  165:       printf("libcurl error: %d\n", res);
  166:       return 4;
  167:     }
  168:   }
  169: 
  170: #ifdef WIN32
  171:   WSACleanup();
  172: #endif
  173:   return 0;
  174: }