1 files changed, 134 insertions, 0 deletions
diff --git a/doc/examples/ex-client-dtls.c b/doc/examples/ex-client-dtls.c
new file mode 100644
index 0000000..095246e
--- /dev/null
+++ b/doc/examples/ex-client-dtls.c
@@ -0,0 +1,134 @@
+/* This example code is placed in the public domain. */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <assert.h>
+#include <unistd.h>
+#include <gnutls/gnutls.h>
+#include <gnutls/dtls.h>
+
+/* A very basic Datagram TLS client, over UDP with X.509 authentication.
+ */
+
+#define CHECK(x) assert((x)>=0)
+#define LOOP_CHECK(rval, cmd) \
+        do { \
+                rval = cmd; \
+        } while(rval == GNUTLS_E_AGAIN || rval == GNUTLS_E_INTERRUPTED); \
+        assert(rval >= 0)
+
+#define MAX_BUF 1024
+#define MSG "GET / HTTP/1.0\r\n\r\n"
+
+extern int udp_connect(void);
+extern void udp_close(int sd);
+extern int verify_certificate_callback(gnutls_session_t session);
+
+int main(void)
+{
+        int ret, sd, ii;
+        gnutls_session_t session;
+        char buffer[MAX_BUF + 1];
+        gnutls_certificate_credentials_t xcred;
+
+        if (gnutls_check_version("3.1.4") == NULL) {
+                fprintf(stderr, "GnuTLS 3.1.4 or later is required for this example\n");
+                exit(1);
+        }
+
+        /* for backwards compatibility with gnutls < 3.3.0 */
+        CHECK(gnutls_global_init());
+
+        /* X509 stuff */
+        CHECK(gnutls_certificate_allocate_credentials(&xcred));
+
+        /* sets the system trusted CAs for Internet PKI */
+        CHECK(gnutls_certificate_set_x509_system_trust(xcred));
+
+        /* Initialize TLS session */
+        CHECK(gnutls_init(&session, GNUTLS_CLIENT | GNUTLS_DATAGRAM));
+
+        /* Use default priorities */
+        CHECK(gnutls_set_default_priority(session));
+
+        /* put the x509 credentials to the current session */
+        CHECK(gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, xcred));
+        CHECK(gnutls_server_name_set(session, GNUTLS_NAME_DNS, "www.example.com",
+                                     strlen("www.example.com")));
+
+        gnutls_session_set_verify_cert(session, "www.example.com", 0);
+
+        /* connect to the peer */
+        sd = udp_connect();
+
+        gnutls_transport_set_int(session, sd);
+
+        /* set the connection MTU */
+        gnutls_dtls_set_mtu(session, 1000);
+        /* gnutls_dtls_set_timeouts(session, 1000, 60000); */
+
+        /* Perform the TLS handshake */
+        do {
+                ret = gnutls_handshake(session);
+        }
+        while (ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN);
+        /* Note that DTLS may also receive GNUTLS_E_LARGE_PACKET */
+
+        if (ret < 0) {
+                fprintf(stderr, "*** Handshake failed\n");
+                gnutls_perror(ret);
+                goto end;
+        } else {
+                char *desc;
+
+                desc = gnutls_session_get_desc(session);
+                printf("- Session info: %s\n", desc);
+                gnutls_free(desc);
+        }
+
+        LOOP_CHECK(ret, gnutls_record_send(session, MSG, strlen(MSG)));
+
+        LOOP_CHECK(ret, gnutls_record_recv(session, buffer, MAX_BUF));
+        if (ret == 0) {
+                printf("- Peer has closed the TLS connection\n");
+                goto end;
+        } else if (ret < 0 && gnutls_error_is_fatal(ret) == 0) {
+                fprintf(stderr, "*** Warning: %s\n", gnutls_strerror(ret));
+        } else if (ret < 0) {
+                fprintf(stderr, "*** Error: %s\n", gnutls_strerror(ret));
+                goto end;
+        }
+
+        if (ret > 0) {
+                printf("- Received %d bytes: ", ret);
+                for (ii = 0; ii < ret; ii++) {
+                        fputc(buffer[ii], stdout);
+                }
+                fputs("\n", stdout);
+        }
+
+        /* It is suggested not to use GNUTLS_SHUT_RDWR in DTLS
+         * connections because the peer's closure message might
+         * be lost */
+        CHECK(gnutls_bye(session, GNUTLS_SHUT_WR));
+
+      end:
+
+        udp_close(sd);
+
+        gnutls_deinit(session);
+
+        gnutls_certificate_free_credentials(xcred);
+
+        gnutls_global_deinit();
+
+        return 0;
+}