doc/examples/ex-serv-srp.c

   1 /* This example code is placed in the public domain. */
   2
   3 #ifdef HAVE_CONFIG_H
   4 #include <config.h>
   5 #endif
   6
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <errno.h>
  10 #include <sys/types.h>
  11 #include <sys/socket.h>
  12 #include <arpa/inet.h>
  13 #include <netinet/in.h>
  14 #include <string.h>
  15 #include <unistd.h>
  16 #include <gnutls/gnutls.h>
  17
  18 #define SRP_PASSWD "tpasswd"
  19 #define SRP_PASSWD_CONF "tpasswd.conf"
  20
  21 #define KEYFILE "key.pem"
  22 #define CERTFILE "cert.pem"
  23 #define CAFILE "/etc/ssl/certs/ca-certificates.crt"
  24
  25 /* This is a sample TLS-SRP echo server.
  26  */
  27
  28 #define SOCKET_ERR(err,s) if(err==-1) {perror(s);return(1);}
  29 #define MAX_BUF 1024
  30 #define PORT 5556               /* listen to 5556 port */
  31
  32 int main(void)
  33 {
  34         int err, listen_sd;
  35         int sd, ret;
  36         struct sockaddr_in sa_serv;
  37         struct sockaddr_in sa_cli;
  38         socklen_t client_len;
  39         char topbuf[512];
  40         gnutls_session_t session;
  41         gnutls_srp_server_credentials_t srp_cred;
  42         gnutls_certificate_credentials_t cert_cred;
  43         char buffer[MAX_BUF + 1];
  44         int optval = 1;
  45         char name[256];
  46
  47         strcpy(name, "Echo Server");
  48
  49         if (gnutls_check_version("3.1.4") == NULL) {
  50                 fprintf(stderr, "GnuTLS 3.1.4 or later is required for this example\n");
  51                 exit(1);
  52         }
  53
  54         /* for backwards compatibility with gnutls < 3.3.0 */
  55         gnutls_global_init();
  56
  57         /* SRP_PASSWD a password file (created with the included srptool utility)
  58          */
  59         gnutls_srp_allocate_server_credentials(&srp_cred);
  60         gnutls_srp_set_server_credentials_file(srp_cred, SRP_PASSWD,
  61                                                SRP_PASSWD_CONF);
  62
  63         gnutls_certificate_allocate_credentials(&cert_cred);
  64         gnutls_certificate_set_x509_trust_file(cert_cred, CAFILE,
  65                                                GNUTLS_X509_FMT_PEM);
  66         gnutls_certificate_set_x509_key_file(cert_cred, CERTFILE, KEYFILE,
  67                                              GNUTLS_X509_FMT_PEM);
  68
  69         /* TCP socket operations
  70          */
  71         listen_sd = socket(AF_INET, SOCK_STREAM, 0);
  72         SOCKET_ERR(listen_sd, "socket");
  73
  74         memset(&sa_serv, '\0', sizeof(sa_serv));
  75         sa_serv.sin_family = AF_INET;
  76         sa_serv.sin_addr.s_addr = INADDR_ANY;
  77         sa_serv.sin_port = htons(PORT); /* Server Port number */
  78
  79         setsockopt(listen_sd, SOL_SOCKET, SO_REUSEADDR, (void *) &optval,
  80                    sizeof(int));
  81
  82         err =
  83             bind(listen_sd, (struct sockaddr *) &sa_serv, sizeof(sa_serv));
  84         SOCKET_ERR(err, "bind");
  85         err = listen(listen_sd, 1024);
  86         SOCKET_ERR(err, "listen");
  87
  88         printf("%s ready. Listening to port '%d'.\n\n", name, PORT);
  89
  90         client_len = sizeof(sa_cli);
  91         for (;;) {
  92                 gnutls_init(&session, GNUTLS_SERVER);
  93                 gnutls_priority_set_direct(session,
  94                                            "NORMAL"
  95                                            ":-KX-ALL:+SRP:+SRP-DSS:+SRP-RSA",
  96                                            NULL);
  97                 gnutls_credentials_set(session, GNUTLS_CRD_SRP, srp_cred);
  98                 /* for the certificate authenticated ciphersuites.
  99                  */
 100                 gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE,
 101                                        cert_cred);
 102
 103                 /* We don't request any certificate from the client.
 104                  * If we did we would need to verify it. One way of
 105                  * doing that is shown in the "Verifying a certificate"
 106                  * example.
 107                  */
 108                 gnutls_certificate_server_set_request(session,
 109                                                       GNUTLS_CERT_IGNORE);
 110
 111                 sd = accept(listen_sd, (struct sockaddr *) &sa_cli,
 112                             &client_len);
 113
 114                 printf("- connection from %s, port %d\n",
 115                        inet_ntop(AF_INET, &sa_cli.sin_addr, topbuf,
 116                                  sizeof(topbuf)), ntohs(sa_cli.sin_port));
 117
 118                 gnutls_transport_set_int(session, sd);
 119
 120                 do {
 121                         ret = gnutls_handshake(session);
 122                 }
 123                 while (ret < 0 && gnutls_error_is_fatal(ret) == 0);
 124
 125                 if (ret < 0) {
 126                         close(sd);
 127                         gnutls_deinit(session);
 128                         fprintf(stderr,
 129                                 "*** Handshake has failed (%s)\n\n",
 130                                 gnutls_strerror(ret));
 131                         continue;
 132                 }
 133                 printf("- Handshake was completed\n");
 134                 printf("- User %s was connected\n",
 135                        gnutls_srp_server_get_username(session));
 136
 137                 /* print_info(session); */
 138
 139                 for (;;) {
 140                         ret = gnutls_record_recv(session, buffer, MAX_BUF);
 141
 142                         if (ret == 0) {
 143                                 printf
 144                                     ("\n- Peer has closed the GnuTLS connection\n");
 145                                 break;
 146                         } else if (ret < 0
 147                                    && gnutls_error_is_fatal(ret) == 0) {
 148                                 fprintf(stderr, "*** Warning: %s\n",
 149                                         gnutls_strerror(ret));
 150                         } else if (ret < 0) {
 151                                 fprintf(stderr, "\n*** Received corrupted "
 152                                         "data(%d). Closing the connection.\n\n",
 153                                         ret);
 154                                 break;
 155                         } else if (ret > 0) {
 156                                 /* echo data back to the client
 157                                  */
 158                                 gnutls_record_send(session, buffer, ret);
 159                         }
 160                 }
 161                 printf("\n");
 162                 /* do not wait for the peer to close the connection. */
 163                 gnutls_bye(session, GNUTLS_SHUT_WR);
 164
 165                 close(sd);
 166                 gnutls_deinit(session);
 167
 168         }
 169         close(listen_sd);
 170
 171         gnutls_srp_free_server_credentials(srp_cred);
 172         gnutls_certificate_free_credentials(cert_cred);
 173
 174         gnutls_global_deinit();
 175
 176         return 0;
 177
 178 }