1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2021, 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.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
write_data(void * ptr,size_t size,size_t nmemb,void * stream)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
closecb(void * clientp,curl_socket_t item)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
opensocket(void * clientp,curlsocktype purpose,struct curl_sockaddr * address)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
sockopt_callback(void * clientp,curl_socket_t curlfd,curlsocktype purpose)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
main(void)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) {
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 }
175