1 files changed, 146 insertions, 0 deletions
diff --git a/doc/examples/ex-client-resume.c b/doc/examples/ex-client-resume.c
new file mode 100644
index 0000000..3161ef3
--- /dev/null
+++ b/doc/examples/ex-client-resume.c
@@ -0,0 +1,146 @@
+/* This example code is placed in the public domain. */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <gnutls/gnutls.h>
+
+extern void check_alert(gnutls_session_t session, int ret);
+extern int tcp_connect(void);
+extern void tcp_close(int sd);
+
+/* A very basic TLS client, with X.509 authentication and server certificate
+ * verification as well as session resumption.
+ *
+ * Note that error recovery is minimal for simplicity.
+ */
+
+#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"
+
+int main(void)
+{
+        int ret;
+        int sd, ii;
+        gnutls_session_t session;
+        char buffer[MAX_BUF + 1];
+        gnutls_certificate_credentials_t xcred;
+
+        /* variables used in session resuming 
+         */
+        int t;
+        gnutls_datum_t sdata;
+
+        /* for backwards compatibility with gnutls < 3.3.0 */
+        CHECK(gnutls_global_init());
+
+        CHECK(gnutls_certificate_allocate_credentials(&xcred));
+        CHECK(gnutls_certificate_set_x509_system_trust(xcred));
+
+        for (t = 0; t < 2; t++) {       /* connect 2 times to the server */
+
+                sd = tcp_connect();
+
+                CHECK(gnutls_init(&session, GNUTLS_CLIENT));
+
+                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);
+
+                CHECK(gnutls_set_default_priority(session));
+
+                gnutls_transport_set_int(session, sd);
+                gnutls_handshake_set_timeout(session,
+                                             GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT);
+
+                gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE,
+                                       xcred);
+
+                if (t > 0) {
+                        /* if this is not the first time we connect */
+                        CHECK(gnutls_session_set_data(session, sdata.data,
+                                                      sdata.size));
+                        gnutls_free(sdata.data);
+                }
+
+                /* Perform the TLS handshake
+                 */
+                do {
+                        ret = gnutls_handshake(session);
+                }
+                while (ret < 0 && gnutls_error_is_fatal(ret) == 0);
+
+                if (ret < 0) {
+                        fprintf(stderr, "*** Handshake failed\n");
+                        gnutls_perror(ret);
+                        goto end;
+                } else {
+                        printf("- Handshake was completed\n");
+                }
+
+                if (t == 0) {   /* the first time we connect */
+                        /* get the session data */
+                        CHECK(gnutls_session_get_data2(session, &sdata));
+                } else { /* the second time we connect */
+
+                        /* check if we actually resumed the previous session */
+                        if (gnutls_session_is_resumed(session) != 0) {
+                                printf("- Previous session was resumed\n");
+                        } else {
+                                fprintf(stderr,
+                                        "*** Previous session was NOT resumed\n");
+                        }
+                }
+
+                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);
+                }
+
+                gnutls_bye(session, GNUTLS_SHUT_RDWR);
+
+              end:
+
+                tcp_close(sd);
+
+                gnutls_deinit(session);
+
+        }                       /* for() */
+
+        gnutls_certificate_free_credentials(xcred);
+
+        gnutls_global_deinit();
+
+        return 0;
+}