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Annotation of embedaddon/curl/docs/examples/externalsocket.c, revision 1.1.1.1

1.1       misho       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: }