1 /*
2 * Copyright 2023 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10 /*
11 * NB: Changes to this file should also be reflected in
12 * doc/man7/ossl-guide-quic-client-block.pod
13 */
14
15 #include <string.h>
16
17 /* Include the appropriate header file for SOCK_DGRAM */
18 #ifdef _WIN32 /* Windows */
19 # include <winsock2.h>
20 #else /* Linux/Unix */
21 # include <sys/socket.h>
22 #endif
23
24 #include <openssl/bio.h>
25 #include <openssl/ssl.h>
26 #include <openssl/err.h>
27
28 /* Helper function to create a BIO connected to the server */
create_socket_bio(const char * hostname,const char * port,int family,BIO_ADDR ** peer_addr)29 static BIO *create_socket_bio(const char *hostname, const char *port,
30 int family, BIO_ADDR **peer_addr)
31 {
32 int sock = -1;
33 BIO_ADDRINFO *res;
34 const BIO_ADDRINFO *ai = NULL;
35 BIO *bio;
36
37 /*
38 * Lookup IP address info for the server.
39 */
40 if (!BIO_lookup_ex(hostname, port, BIO_LOOKUP_CLIENT, family, SOCK_DGRAM, 0,
41 &res))
42 return NULL;
43
44 /*
45 * Loop through all the possible addresses for the server and find one
46 * we can connect to.
47 */
48 for (ai = res; ai != NULL; ai = BIO_ADDRINFO_next(ai)) {
49 /*
50 * Create a UDP socket. We could equally use non-OpenSSL calls such
51 * as "socket" here for this and the subsequent connect and close
52 * functions. But for portability reasons and also so that we get
53 * errors on the OpenSSL stack in the event of a failure we use
54 * OpenSSL's versions of these functions.
55 */
56 sock = BIO_socket(BIO_ADDRINFO_family(ai), SOCK_DGRAM, 0, 0);
57 if (sock == -1)
58 continue;
59
60 /* Connect the socket to the server's address */
61 if (!BIO_connect(sock, BIO_ADDRINFO_address(ai), 0)) {
62 BIO_closesocket(sock);
63 sock = -1;
64 continue;
65 }
66
67 /* Set to nonblocking mode */
68 if (!BIO_socket_nbio(sock, 1)) {
69 BIO_closesocket(sock);
70 sock = -1;
71 continue;
72 }
73
74 break;
75 }
76
77 if (sock != -1) {
78 *peer_addr = BIO_ADDR_dup(BIO_ADDRINFO_address(ai));
79 if (*peer_addr == NULL) {
80 BIO_closesocket(sock);
81 return NULL;
82 }
83 }
84
85 /* Free the address information resources we allocated earlier */
86 BIO_ADDRINFO_free(res);
87
88 /* If sock is -1 then we've been unable to connect to the server */
89 if (sock == -1)
90 return NULL;
91
92 /* Create a BIO to wrap the socket */
93 bio = BIO_new(BIO_s_datagram());
94 if (bio == NULL) {
95 BIO_closesocket(sock);
96 return NULL;
97 }
98
99 /*
100 * Associate the newly created BIO with the underlying socket. By
101 * passing BIO_CLOSE here the socket will be automatically closed when
102 * the BIO is freed. Alternatively you can use BIO_NOCLOSE, in which
103 * case you must close the socket explicitly when it is no longer
104 * needed.
105 */
106 BIO_set_fd(bio, sock, BIO_CLOSE);
107
108 return bio;
109 }
110
111 /*
112 * Simple application to send a basic HTTP/1.0 request to a server and
113 * print the response on the screen. Note that HTTP/1.0 over QUIC is
114 * non-standard and will not typically be supported by real world servers. This
115 * is for demonstration purposes only.
116 */
main(int argc,char * argv[])117 int main(int argc, char *argv[])
118 {
119 SSL_CTX *ctx = NULL;
120 SSL *ssl = NULL;
121 BIO *bio = NULL;
122 int res = EXIT_FAILURE;
123 int ret;
124 unsigned char alpn[] = { 8, 'h', 't', 't', 'p', '/', '1', '.', '0' };
125 const char *request_start = "GET / HTTP/1.0\r\nConnection: close\r\nHost: ";
126 const char *request_end = "\r\n\r\n";
127 size_t written, readbytes;
128 char buf[160];
129 BIO_ADDR *peer_addr = NULL;
130 char *hostname, *port;
131 int argnext = 1;
132 int ipv6 = 0;
133
134 if (argc < 3) {
135 printf("Usage: quic-client-block [-6] hostname port\n");
136 goto end;
137 }
138
139 if (!strcmp(argv[argnext], "-6")) {
140 if (argc < 4) {
141 printf("Usage: quic-client-block [-6] hostname port\n");
142 goto end;
143 }
144 ipv6 = 1;
145 argnext++;
146 }
147 hostname = argv[argnext++];
148 port = argv[argnext];
149
150 /*
151 * Create an SSL_CTX which we can use to create SSL objects from. We
152 * want an SSL_CTX for creating clients so we use
153 * OSSL_QUIC_client_method() here.
154 */
155 ctx = SSL_CTX_new(OSSL_QUIC_client_method());
156 if (ctx == NULL) {
157 printf("Failed to create the SSL_CTX\n");
158 goto end;
159 }
160
161 /*
162 * Configure the client to abort the handshake if certificate
163 * verification fails. Virtually all clients should do this unless you
164 * really know what you are doing.
165 */
166 SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER, NULL);
167
168 /* Use the default trusted certificate store */
169 if (!SSL_CTX_set_default_verify_paths(ctx)) {
170 printf("Failed to set the default trusted certificate store\n");
171 goto end;
172 }
173
174 /* Create an SSL object to represent the TLS connection */
175 ssl = SSL_new(ctx);
176 if (ssl == NULL) {
177 printf("Failed to create the SSL object\n");
178 goto end;
179 }
180
181 /*
182 * Create the underlying transport socket/BIO and associate it with the
183 * connection.
184 */
185 bio = create_socket_bio(hostname, port, ipv6 ? AF_INET6 : AF_INET, &peer_addr);
186 if (bio == NULL) {
187 printf("Failed to crete the BIO\n");
188 goto end;
189 }
190 SSL_set_bio(ssl, bio, bio);
191
192 /*
193 * Tell the server during the handshake which hostname we are attempting
194 * to connect to in case the server supports multiple hosts.
195 */
196 if (!SSL_set_tlsext_host_name(ssl, hostname)) {
197 printf("Failed to set the SNI hostname\n");
198 goto end;
199 }
200
201 /*
202 * Ensure we check during certificate verification that the server has
203 * supplied a certificate for the hostname that we were expecting.
204 * Virtually all clients should do this unless you really know what you
205 * are doing.
206 */
207 if (!SSL_set1_host(ssl, hostname)) {
208 printf("Failed to set the certificate verification hostname");
209 goto end;
210 }
211
212 /* SSL_set_alpn_protos returns 0 for success! */
213 if (SSL_set_alpn_protos(ssl, alpn, sizeof(alpn)) != 0) {
214 printf("Failed to set the ALPN for the connection\n");
215 goto end;
216 }
217
218 /* Set the IP address of the remote peer */
219 if (!SSL_set1_initial_peer_addr(ssl, peer_addr)) {
220 printf("Failed to set the initial peer address\n");
221 goto end;
222 }
223
224 /* Do the handshake with the server */
225 if (SSL_connect(ssl) < 1) {
226 printf("Failed to connect to the server\n");
227 /*
228 * If the failure is due to a verification error we can get more
229 * information about it from SSL_get_verify_result().
230 */
231 if (SSL_get_verify_result(ssl) != X509_V_OK)
232 printf("Verify error: %s\n",
233 X509_verify_cert_error_string(SSL_get_verify_result(ssl)));
234 goto end;
235 }
236
237 /* Write an HTTP GET request to the peer */
238 if (!SSL_write_ex(ssl, request_start, strlen(request_start), &written)) {
239 printf("Failed to write start of HTTP request\n");
240 goto end;
241 }
242 if (!SSL_write_ex(ssl, hostname, strlen(hostname), &written)) {
243 printf("Failed to write hostname in HTTP request\n");
244 goto end;
245 }
246 if (!SSL_write_ex(ssl, request_end, strlen(request_end), &written)) {
247 printf("Failed to write end of HTTP request\n");
248 goto end;
249 }
250
251 /*
252 * Get up to sizeof(buf) bytes of the response. We keep reading until the
253 * server closes the connection.
254 */
255 while (SSL_read_ex(ssl, buf, sizeof(buf), &readbytes)) {
256 /*
257 * OpenSSL does not guarantee that the returned data is a string or
258 * that it is NUL terminated so we use fwrite() to write the exact
259 * number of bytes that we read. The data could be non-printable or
260 * have NUL characters in the middle of it. For this simple example
261 * we're going to print it to stdout anyway.
262 */
263 fwrite(buf, 1, readbytes, stdout);
264 }
265 /* In case the response didn't finish with a newline we add one now */
266 printf("\n");
267
268 /*
269 * Check whether we finished the while loop above normally or as the
270 * result of an error. The 0 argument to SSL_get_error() is the return
271 * code we received from the SSL_read_ex() call. It must be 0 in order
272 * to get here. Normal completion is indicated by SSL_ERROR_ZERO_RETURN. In
273 * QUIC terms this means that the peer has sent FIN on the stream to
274 * indicate that no further data will be sent.
275 */
276 switch (SSL_get_error(ssl, 0)) {
277 case SSL_ERROR_ZERO_RETURN:
278 /* Normal completion of the stream */
279 break;
280
281 case SSL_ERROR_SSL:
282 /*
283 * Some stream fatal error occurred. This could be because of a stream
284 * reset - or some failure occurred on the underlying connection.
285 */
286 switch (SSL_get_stream_read_state(ssl)) {
287 case SSL_STREAM_STATE_RESET_REMOTE:
288 printf("Stream reset occurred\n");
289 /* The stream has been reset but the connection is still healthy. */
290 break;
291
292 case SSL_STREAM_STATE_CONN_CLOSED:
293 printf("Connection closed\n");
294 /* Connection is already closed. Skip SSL_shutdown() */
295 goto end;
296
297 default:
298 printf("Unknown stream failure\n");
299 break;
300 }
301 break;
302
303 default:
304 /* Some other unexpected error occurred */
305 printf ("Failed reading remaining data\n");
306 break;
307 }
308
309 /*
310 * Repeatedly call SSL_shutdown() until the connection is fully
311 * closed.
312 */
313 do {
314 ret = SSL_shutdown(ssl);
315 if (ret < 0) {
316 printf("Error shutting down: %d\n", ret);
317 goto end;
318 }
319 } while (ret != 1);
320
321 /* Success! */
322 res = EXIT_SUCCESS;
323 end:
324 /*
325 * If something bad happened then we will dump the contents of the
326 * OpenSSL error stack to stderr. There might be some useful diagnostic
327 * information there.
328 */
329 if (res == EXIT_FAILURE)
330 ERR_print_errors_fp(stderr);
331
332 /*
333 * Free the resources we allocated. We do not free the BIO object here
334 * because ownership of it was immediately transferred to the SSL object
335 * via SSL_set_bio(). The BIO will be freed when we free the SSL object.
336 */
337 SSL_free(ssl);
338 SSL_CTX_free(ctx);
339 BIO_ADDR_free(peer_addr);
340 return res;
341 }
342
