/mandos/trunk

extern "C" {

#include <sys/types.h> //socket, setsockopt, bind, listen, accept,

  // inet_ntop,

#include <sys/socket.h> //socket, setsockopt, bind, listen, accept,

  // inet_ntop

#include <sys/ioctl.h> //ioctl, sockaddr_ll, ifreq

#include <unistd.h> //write, close

#include <netinet/ip.h> 	// sockaddr_in

#include <gnutls/gnutls.h>

#include <gnutls/x509.h> 	// gnutls_x509_crt_init, gnutls_x509_crt_import, gnutls_x509_crt_get_dn

#include <arpa/inet.h> 		// inet_ntop, htons

#include <net/if.h> //ifreq

}

#include <cstdio>

#include <cstring>

#include <cerrno>

#include <algorithm> 		// std::max

#include <cstdlib> 		// exit()

#include <fstream> 		// std::ifstream

#include <string> 		// std::string

#include <map> 			// std::map

#include <iostream> 		// cout

#include <ostream> 		// <<

#define SOCKET_ERR(err,s) if(err<0) {perror(s);exit(1);}

#define PORT 49001

#define KEYFILE "key.pem"

#define CERTFILE "cert.pem"

#define CAFILE "ca.pem"

#define CRLFILE "crl.pem"

#define DH_BITS 1024

using std::string;

using std::ifstream;

using std::map;

using std::cout;

/* These are global */

gnutls_certificate_credentials_t x509_cred;

map<string,string> table;

static gnutls_dh_params_t dh_params;

static int

generate_dh_params ()

{

  /* Generate Diffie Hellman parameters - for use with DHE

   * kx algorithms. These should be discarded and regenerated

   * once a day, once a week or once a month. Depending on the

   * security requirements.

   */

  gnutls_dh_params_init (&dh_params);

  gnutls_dh_params_generate2 (dh_params, DH_BITS);

  return 0;

}

gnutls_session_t

initialize_tls_session ()

{

  gnutls_session_t session;

  gnutls_global_init ();

  gnutls_certificate_allocate_credentials (&x509_cred);

  gnutls_certificate_set_x509_trust_file (x509_cred, CAFILE,

					  GNUTLS_X509_FMT_PEM);

  gnutls_certificate_set_x509_crl_file (x509_cred, CRLFILE,

					GNUTLS_X509_FMT_PEM);

  gnutls_certificate_set_x509_key_file (x509_cred, CERTFILE, KEYFILE,

					GNUTLS_X509_FMT_PEM);

  generate_dh_params ();

  gnutls_certificate_set_dh_params (x509_cred, dh_params);

  gnutls_init (&session, GNUTLS_SERVER);

  gnutls_set_default_priority (session);

  gnutls_credentials_set (session, GNUTLS_CRD_CERTIFICATE, x509_cred);

  // request client certificate if any.

  gnutls_certificate_server_set_request (session, GNUTLS_CERT_REQUEST);

  gnutls_dh_set_prime_bits (session, DH_BITS);

  return session;

}

void udpreply(int &sd){

  struct sockaddr_in6 sa_cli;

  int ret;

  char buffer[512];

  {

    socklen_t sa_cli_len = sizeof(sa_cli);

    ret = recvfrom(sd, buffer, 512,0,

		   reinterpret_cast<sockaddr *>(& sa_cli), & sa_cli_len);

    SOCKET_ERR (ret, "recvfrom");

  }

  if (strncmp(buffer,"Marco", 5) == 0){

    ret = sendto(sd, "Polo", 4, 0, reinterpret_cast<sockaddr *>(& sa_cli),

		 sizeof(sa_cli));

    SOCKET_ERR (ret, "sendto");

  }

}

void tcpreply(int sd, struct sockaddr_in6 *sa_cli, gnutls_session_t session){

  int ret;

  unsigned int status;

  char buffer[512];

  int exit_status = 0;

  char dn[128];

#define DIE(s){ exit_status = s; goto tcpreply_die; }

  printf ("- TCP connection from %s, port %d\n",

	  inet_ntop (AF_INET6, &(sa_cli->sin6_addr), buffer,

		     sizeof (buffer)), ntohs (sa_cli->sin6_port));

  gnutls_transport_set_ptr (session, reinterpret_cast<gnutls_transport_ptr_t> (sd));

  ret = gnutls_handshake (session);

  if (ret < 0)

    {

      close (sd);

      gnutls_deinit (session);

      fprintf (stderr, "*** Handshake has failed (%s)\n\n",

	       gnutls_strerror (ret));

      DIE(1);

    }

  printf ("- Handshake was completed\n");

  //time to validate

  if (gnutls_certificate_type_get (session) != GNUTLS_CRT_X509){

    printf("Recived certificate not X.509\n");

    DIE(1);

  }

  {

    const gnutls_datum_t *cert_list;

    unsigned int cert_list_size = 0;

    gnutls_x509_crt_t cert;

    size_t size;

    cert_list = gnutls_certificate_get_peers (session, &cert_list_size);

    printf ("Peer provided %d certificates.\n", cert_list_size);

    if (cert_list_size == 0){

      printf("No certificates recived\n");

      DIE(1);

    }

    gnutls_x509_crt_init (&cert);

    // XXX -Checking only first cert, might want to check them all

    gnutls_x509_crt_import (cert, &cert_list[0], GNUTLS_X509_FMT_DER);

    size = sizeof (dn);

    gnutls_x509_crt_get_dn (cert, dn, &size);

    printf ("DN: %s\n", dn);

  }

  ret = gnutls_certificate_verify_peers2 (session, &status);

  if (ret < 0){

      printf ("Verify failed\n");

      DIE(1);

  }

  if (status & (GNUTLS_CERT_INVALID | GNUTLS_CERT_SIGNER_NOT_FOUND | GNUTLS_CERT_REVOKED)) {

    if (status & GNUTLS_CERT_INVALID) {

      printf ("The certificate is not trusted.\n");

    }

    if (status & GNUTLS_CERT_SIGNER_NOT_FOUND){

      printf ("The certificate hasn't got a known issuer.\n");

    }

    if (status & GNUTLS_CERT_REVOKED){

      printf ("The certificate has been revoked.\n");

    }

    DIE(1);

  }  

  if (table.find(dn) != table.end()){

    gnutls_record_send (session, table[dn].c_str(), table[dn].size());

    printf("Password sent to client\n");

  }

  else {

    printf("dn not in list of allowed clients\n");

  }

 tcpreply_die:

  gnutls_bye (session, GNUTLS_SHUT_WR);

  close(sd);

  gnutls_deinit (session);

  gnutls_certificate_free_credentials (x509_cred);

  gnutls_global_deinit ();

  exit(exit_status);

}

void badconfigparser(string file){

  string dn;

  string pw;

  string pwfile;

  ifstream infile (file.c_str());

  while(infile){

    getline(infile, dn, '\n');

    if(not infile){

      break;

    }

    getline(infile, pw, '\n');

    if(not infile){

      break;

    }

    getline(infile, pwfile, '\n');

    if(not infile){

      break;

    }

    if(pw.empty()){

      ifstream pwf(pwfile.c_str());

      std::string tmp;

      while(true){

	getline(pwf,tmp);

	if (not pwf){

	  break;

	}

	pw = pw + tmp + '\n';

      }

    }

    table[dn]=pw;

  }

  infile.close();

}

int main (){

  int ret, err, udp_listen_sd, tcp_listen_sd;

  struct sockaddr_in6 sa_serv;

  struct sockaddr_in6 sa_cli;

  int optval = 1;

  socklen_t client_len;

  gnutls_session_t session;

  fd_set rfds_orig;

  badconfigparser(string("clients.conf"));

  session = initialize_tls_session ();

  //UDP IPv6 socket creation

  udp_listen_sd = socket (PF_INET6, SOCK_DGRAM, 0);

  SOCKET_ERR (udp_listen_sd, "socket");

  memset (&sa_serv, '\0', sizeof (sa_serv));

  sa_serv.sin6_family = AF_INET6;

  sa_serv.sin6_addr = in6addr_any; //XXX only listen to link local?

  sa_serv.sin6_port = htons (PORT);	/* Server Port number */

  ret = setsockopt (udp_listen_sd, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof (optval));

  SOCKET_ERR(ret,"setsockopt reuseaddr");

  ret = setsockopt(udp_listen_sd, SOL_SOCKET, SO_BINDTODEVICE, "eth0", 5);

  SOCKET_ERR(ret,"setsockopt bindtodevice");

  {

    int flag = 1;

    ret = setsockopt(udp_listen_sd, SOL_SOCKET, SO_BROADCAST, & flag, sizeof(flag));

    SOCKET_ERR(ret,"setsockopt broadcast");

  }

  err = bind (udp_listen_sd, reinterpret_cast<const sockaddr *> (& sa_serv),

	      sizeof (sa_serv));

  SOCKET_ERR (err, "bind");

  //UDP socket creation done

  //TCP IPv6 socket creation

  tcp_listen_sd = socket(PF_INET6, SOCK_STREAM, 0);

  SOCKET_ERR(tcp_listen_sd,"socket");

  setsockopt(tcp_listen_sd, SOL_SOCKET, SO_BINDTODEVICE, "eth0", 5);

  SOCKET_ERR(ret,"setsockopt bindtodevice");

  ret = setsockopt (tcp_listen_sd, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof (optval));

  SOCKET_ERR(ret,"setsockopt reuseaddr");

  err = bind (tcp_listen_sd, reinterpret_cast<const sockaddr *> (& sa_serv),

	      sizeof (sa_serv));

  SOCKET_ERR (err, "bind");

  err = listen (tcp_listen_sd, 1024);

  SOCKET_ERR (err, "listen");

  //TCP IPv6 sockets creation done

  FD_ZERO(&rfds_orig);

  FD_SET(udp_listen_sd, &rfds_orig);

  FD_SET(tcp_listen_sd, &rfds_orig);

  printf ("Server ready. Listening to port '%d' on UDP and TCP.\n\n", PORT);

  for(;;){

    fd_set rfds = rfds_orig;

    ret = select(std::max(udp_listen_sd, tcp_listen_sd)+1, &rfds, 0, 0, 0);

    SOCKET_ERR(ret,"select");

    if (FD_ISSET(udp_listen_sd, &rfds)){

      udpreply(udp_listen_sd);

    }

    if (FD_ISSET(tcp_listen_sd, &rfds)){

      client_len = sizeof(sa_cli);

      int sd = accept (tcp_listen_sd,

	       reinterpret_cast<struct sockaddr *> (& sa_cli),

	       &client_len);

      SOCKET_ERR(sd,"accept"); //xxx not dieing when just connection abort      

      switch(fork()){

	case 0:

	  tcpreply(sd, &sa_cli, session);

	  return 0;

	  break;

      case -1:

	perror("fork");

	close(tcp_listen_sd);

	close(udp_listen_sd);

	return 1;

	break;

      default:

	break;

      }

    }

  }

  close(tcp_listen_sd);

  close(udp_listen_sd);

  return 0;

}