1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 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 * SPDX-License-Identifier: curl
22 *
23 ***************************************************************************/
24 /* <DESC>
25 * Pass in a custom socket for libcurl to use.
26 * </DESC>
27 */
28 #include <stdio.h>
29 #include <string.h>
30 #include <stdlib.h>
31 #include <curl/curl.h>
32
33 #ifdef _WIN32
34 #include <winsock2.h>
35 #define close closesocket
36 #else
37 #include <sys/types.h> /* socket types */
38 #include <sys/socket.h> /* socket definitions */
39 #include <netinet/in.h>
40 #include <arpa/inet.h> /* inet (3) functions */
41 #include <unistd.h> /* misc. Unix functions */
42 #endif
43
44 #include <errno.h>
45
46 /* The IP address and port number to connect to */
47 #define IPADDR "127.0.0.1"
48 #define PORTNUM 80
49
50 #ifndef INADDR_NONE
51 #define INADDR_NONE 0xffffffff
52 #endif
53
write_data(void * ptr,size_t size,size_t nmemb,void * stream)54 static size_t write_data(void *ptr, size_t size, size_t nmemb, void *stream)
55 {
56 size_t written = fwrite(ptr, size, nmemb, (FILE *)stream);
57 return written;
58 }
59
closecb(void * clientp,curl_socket_t item)60 static int closecb(void *clientp, curl_socket_t item)
61 {
62 (void)clientp;
63 printf("libcurl wants to close %d now\n", (int)item);
64 return 0;
65 }
66
opensocket(void * clientp,curlsocktype purpose,struct curl_sockaddr * address)67 static curl_socket_t opensocket(void *clientp,
68 curlsocktype purpose,
69 struct curl_sockaddr *address)
70 {
71 curl_socket_t sockfd;
72 (void)purpose;
73 (void)address;
74 sockfd = *(curl_socket_t *)clientp;
75 /* the actual externally set socket is passed in via the OPENSOCKETDATA
76 option */
77 return sockfd;
78 }
79
sockopt_callback(void * clientp,curl_socket_t curlfd,curlsocktype purpose)80 static int sockopt_callback(void *clientp, curl_socket_t curlfd,
81 curlsocktype purpose)
82 {
83 (void)clientp;
84 (void)curlfd;
85 (void)purpose;
86 /* This return code was added in libcurl 7.21.5 */
87 return CURL_SOCKOPT_ALREADY_CONNECTED;
88 }
89
main(void)90 int main(void)
91 {
92 CURL *curl;
93 CURLcode res;
94 struct sockaddr_in servaddr; /* socket address structure */
95 curl_socket_t sockfd;
96
97 #ifdef _WIN32
98 WSADATA wsaData;
99 int initwsa = WSAStartup(MAKEWORD(2, 2), &wsaData);
100 if(initwsa) {
101 printf("WSAStartup failed: %d\n", initwsa);
102 return 1;
103 }
104 #endif
105
106 curl = curl_easy_init();
107 if(curl) {
108 /*
109 * Note that libcurl will internally think that you connect to the host
110 * and port that you specify in the URL option.
111 */
112 curl_easy_setopt(curl, CURLOPT_URL, "http://99.99.99.99:9999");
113
114 /* Create the socket "manually" */
115 sockfd = socket(AF_INET, SOCK_STREAM, 0);
116 if(sockfd == CURL_SOCKET_BAD) {
117 printf("Error creating listening socket.\n");
118 return 3;
119 }
120
121 memset(&servaddr, 0, sizeof(servaddr));
122 servaddr.sin_family = AF_INET;
123 servaddr.sin_port = htons(PORTNUM);
124
125 servaddr.sin_addr.s_addr = inet_addr(IPADDR);
126 if(INADDR_NONE == servaddr.sin_addr.s_addr) {
127 close(sockfd);
128 return 2;
129 }
130
131 if(connect(sockfd, (struct sockaddr *) &servaddr, sizeof(servaddr)) ==
132 -1) {
133 close(sockfd);
134 printf("client error: connect: %s\n", strerror(errno));
135 return 1;
136 }
137
138 /* no progress meter please */
139 curl_easy_setopt(curl, CURLOPT_NOPROGRESS, 1L);
140
141 /* send all data to this function */
142 curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
143
144 /* call this function to get a socket */
145 curl_easy_setopt(curl, CURLOPT_OPENSOCKETFUNCTION, opensocket);
146 curl_easy_setopt(curl, CURLOPT_OPENSOCKETDATA, &sockfd);
147
148 /* call this function to close sockets */
149 curl_easy_setopt(curl, CURLOPT_CLOSESOCKETFUNCTION, closecb);
150 curl_easy_setopt(curl, CURLOPT_CLOSESOCKETDATA, &sockfd);
151
152 /* call this function to set options for the socket */
153 curl_easy_setopt(curl, CURLOPT_SOCKOPTFUNCTION, sockopt_callback);
154
155 curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);
156
157 res = curl_easy_perform(curl);
158
159 curl_easy_cleanup(curl);
160
161 close(sockfd);
162
163 if(res) {
164 printf("libcurl error: %d\n", res);
165 return 4;
166 }
167 }
168
169 #ifdef _WIN32
170 WSACleanup();
171 #endif
172 return 0;
173 }
174