예제 #1
0
파일: server.c 프로젝트: kjseefried/didentd
main()
{
  char *x;
  int udp53;

  x = env_get("IP");
  if (!x)
    strerr_die2x(111,fatal,"$IP not set");
  if (!ip4_scan(x,ip))
    strerr_die3x(111,fatal,"unable to parse IP address ",x);

  udp53 = socket_udp();
  if (udp53 == -1)
    strerr_die2sys(111,fatal,"unable to create UDP socket: ");
  if (socket_bind4_reuse(udp53,ip,53) == -1)
    strerr_die2sys(111,fatal,"unable to bind UDP socket: ");

  droproot(fatal);

  initialize();
  
  ndelay_off(udp53);
  socket_tryreservein(udp53,65536);

  for (;;) {
    len = socket_recv4(udp53,buf,sizeof buf,ip,&port);
    if (len < 0) continue;
    if (!doit()) continue;
    if (response_len > 512) response_tc();
    socket_send4(udp53,response,response_len,ip,port);
    /* may block for buffer space; if it fails, too bad */
  }
}
예제 #2
0
int socket_udp6(void)
{
#ifdef LIBC_HAS_IP6
  int s;

  if (noipv6) goto compat;
  s = socket(PF_INET6,SOCK_DGRAM,0);
  if (s == -1) {
    if (errno == EINVAL || errno == EAFNOSUPPORT) {
compat:
      s=socket(AF_INET,SOCK_DGRAM,0);
      noipv6=1;
      if (s==-1) return -1;
    } else
    return -1;
  }
  if (ndelay_on(s) == -1) { close(s); return -1; }
#ifdef IPV6_V6ONLY
  {
    int zero=0;
    setsockopt(s,IPPROTO_IPV6,IPV6_V6ONLY,(void*)&zero,sizeof(zero));
  }
#endif
  return s;
#else
  return socket_udp();
#endif
}
예제 #3
0
static int udpserver_create(const char* ip, int port)
{
    int ret;
    socket_t socket;
    struct sockaddr_in addr;

    // new a UDP socket
    socket = socket_udp();
    if(socket_error == socket)
        return 0;

    // reuse addr
    socket_setreuseaddr(socket, 1);

    // bind
    if(ip && ip[0])
    {
        ret = socket_addr_ipv4(&addr, ip, (unsigned short)port);
        if(0 == ret)
            ret = socket_bind(socket, (struct sockaddr*)&addr, sizeof(addr));
    }
    else
    {
        ret = socket_bind_any(socket, (unsigned short)port);
    }

    if(0 != ret)
    {
        socket_close(socket);
        return 0;
    }

    return socket;
}
예제 #4
0
void socket_call_handler(unsigned long long uniqueSockID, int threads,
		unsigned char *buf, ssize_t len) {

	int domain;
	unsigned int type;
	int protocol;
	u_char *pt;

	PRINT_DEBUG("socket call handler1");
	PRINT_DEBUG("%llu", uniqueSockID);

	pt = buf;

	domain = *(int *) pt;
	pt += sizeof(int);

	type = *(unsigned int *) pt;
	pt += sizeof(unsigned int);

	protocol = *(int *) pt;
	pt += sizeof(int);

	if (pt - buf != len) {
		PRINT_DEBUG("READING ERROR! CRASH, diff=%d len=%d", pt - buf, len);
		nack_send(uniqueSockID, socket_call);
		return;
	}

	PRINT_DEBUG("socket call handler2");

	PRINT_DEBUG("%d,%d,%d", domain, protocol, type);
	if (domain != AF_INET) {
		PRINT_DEBUG("Wrong domain, only AF_INET us supported");
		nack_send(uniqueSockID, socket_call);
		return;
	}
	if (type == SOCK_DGRAM) {
		socket_udp(domain, type, protocol, uniqueSockID);
		return;
	} else if (type == SOCK_STREAM) {
		socket_tcp(domain, type, protocol, uniqueSockID);
		return;
	} else if (type == SOCK_RAW && (protocol == IPPROTO_ICMP)) {
		socket_icmp(domain, type, protocol, uniqueSockID);
		return;
	}

	else {
		PRINT_DEBUG("non supported socket type");
		return;
	}

	return;
}
예제 #5
0
int socket_udp6(void)
{
#ifdef LIBC_HAS_IP6
  int s;

  if (noipv6) goto compat;
  s = socket(PF_INET6,SOCK_DGRAM,0);
  if (s == -1) {
    if (errno == EINVAL || errno == EAFNOSUPPORT) {
compat:
      s=socket(AF_INET,SOCK_DGRAM,0);
      noipv6=1;
      if (s==-1) return -1;
    } else
    return -1;
  }
  return s;
#else
  return socket_udp();
#endif
}
예제 #6
0
static int thisudp(struct dns_transmit *d)
{
  const char *ip;

  socketfree(d);

  while (d->udploop < 4) {
    for (;d->curserver < 16;++d->curserver) {
      ip = d->servers + 4 * d->curserver;
      if (byte_diff(ip,4,"\0\0\0\0")) {
	d->query[2] = dns_random(256);
	d->query[3] = dns_random(256);
  
        d->s1 = 1 + socket_udp();
        if (!d->s1) { dns_transmit_free(d); return -1; }
	if (randombind(d) == -1) { dns_transmit_free(d); return -1; }

        if (socket_connect4(d->s1 - 1,ip,53) == 0)
          if (send(d->s1 - 1,d->query + 2,d->querylen - 2,0) == d->querylen - 2) {
            struct taia now;
            taia_now(&now);
            taia_uint(&d->deadline,timeouts[d->udploop]);
            taia_add(&d->deadline,&d->deadline,&now);
            d->tcpstate = 0;
            return 0;
          }
  
        socketfree(d);
      }
    }

    ++d->udploop;
    d->curserver = 0;
  }

  dns_transmit_free(d); return -1;
}
예제 #7
0
파일: server.c 프로젝트: edmonds/pcaputils
int setup_udp_server_socket(const char ip[4], const char ip6[16], u16 port) {
    char sip[FMT_IP6];
    int fd;

    fd = socket_udp6();
    if(fd >= 0) {
        if(socket_bind6(fd, ip6, port, 0) == -1) {
            close(fd);
            fd = socket_udp();
            if(socket_bind4(fd, ip, port) == -1) {
                ERROR("unable to create server socket: %s", strerror(errno));
            } else {
                fmt_ip4(sip, ip);
                DEBUG("bound UDP socket on %s:%hu", sip, port);
            }
        } else {
            fmt_ip6(sip, ip6);
            DEBUG("bound UDP socket on [%s]:%hu", sip, port);
        }
    } else {
        ERROR("unable to create UDP socket: %s", strerror(errno));
    }
    return fd;
}
예제 #8
0
int
main (int argc, char *argv[])
{
    time_t t = 0;
    char *x = NULL;
    struct sigaction sa;
    iopause_fd *iop = NULL;
    int i = 0, n = 0, *udp53 = NULL;

    prog = strdup ((x = strrchr (argv[0], '/')) != NULL ? x + 1 : argv[0]);

    sa.sa_handler = handle_term;
    sigaction (SIGINT, &sa, NULL);
    sigaction (SIGTERM, &sa, NULL);

    sa.sa_handler = SIG_IGN;
    sigaction (SIGPIPE, &sa, NULL);

    i = check_option (argc, argv);
    argc -= i;
    argv += i;

    if (mode & DAEMON)
    {
        i = fork ();
        if (i == -1)
            err (-1, "could not fork a daemon process");
        if (i > 0)
            return 0;
    }

    time (&t);
    memset (buf, 0, sizeof (buf));
    strftime (buf, sizeof (buf), "%b-%d %Y %T %Z", localtime (&t));
    warnx ("version %s: starting: %s\n", VERSION, buf);

    set_timezone ();
    if (debug_level)
        warnx ("TIMEZONE: %s", env_get ("TZ"));

    initialize ();
    if (!debug_level)
        if ((x = env_get ("DEBUG_LEVEL")))
            debug_level = atol (x);
    warnx ("DEBUG_LEVEL set to `%d'", debug_level);

    if ((x = env_get ("DATALIMIT")))
    {
        struct rlimit r;
        unsigned long dlimit = atol (x);

        if (getrlimit (RLIMIT_DATA,  &r) != 0)
            err (-1, "could not get resource RLIMIT_DATA");

        r.rlim_cur = (dlimit <= r.rlim_max) ? dlimit : r.rlim_max;

        if (setrlimit (RLIMIT_DATA, &r) != 0)
            err (-1, "could not set resource RLIMIT_DATA");

        if (debug_level)
            warnx ("DATALIMIT set to `%ld' bytes", r.rlim_cur);
    }

    if (!(x = env_get ("IP")))
        err (-1, "$IP not set");
    for (i = 0; (unsigned)i < strlen (x); i++)
        n = (x[i] == ',') ? n+1 : n;
    if (!(udp53 = calloc (n+1, sizeof (int))))
        err (-1, "could not allocate enough memory for udp53");
    if (!(iop = calloc (n+1, sizeof (iopause_fd))))
        err (-1, "could not allocate enough memory for iop");

    i = n = 0;
    while (x[i])
    {
        unsigned int l = 0;

        if (!(l = ip4_scan(x+i, ip)))
            errx (-1, "could not parse IP address `%s'", x + i);

        udp53[n] = socket_udp();
        if (udp53[n] == -1)
            errx (-1, "could not open UDP socket");
        if (socket_bind4_reuse (udp53[n], ip, server_port) == -1)
            errx (-1, "could not bind UDP socket");

        ndelay_off (udp53[n]);
        socket_tryreservein (udp53[n], 65536);

        iop[n].fd = udp53[n];
        iop[n].events = IOPAUSE_READ;

        n++;
        i += (x[i + l] == ',') ? l + 1 : l;
    }

    droproot ();
    while (1)
    {
        struct taia stamp;
        struct in_addr odst; /* original destination IP */
        struct taia deadline;

        taia_now (&stamp);
        taia_uint (&deadline, 300);
        taia_add (&deadline, &deadline, &stamp);
        iopause (iop, n, &deadline, &stamp);

        for (i = 0; i < n; i++)
        {
            if (!iop[i].revents)
                continue;

            len = socket_recv4 (udp53[i], buf, sizeof (buf), ip, &port, &odst);
            if (len < 0)
                continue;
            if (!doit ())
                continue;
            if (response_len > 512)
                response_tc ();

            /* may block for buffer space; if it fails, too bad */
            len = socket_send4 (udp53[i], response,
                                response_len, ip, port, &odst);
            if (len < 0)
                continue;
            if (debug_level > 1)
                log_querydone(qnum, response, response_len);
        }
    }

    return 0;
}
예제 #9
0
int
main (int argc, char *argv[])
{
    int i = 0;
    time_t t = 0;
    struct sigaction sa;
    unsigned long cachesize = 0;
    char *x = NULL, char_seed[128];

    sa.sa_handler = handle_term;
    sigaction (SIGINT, &sa, NULL);
    sigaction (SIGTERM, &sa, NULL);

    sa.sa_handler = SIG_IGN;
    sigaction (SIGPIPE, &sa, NULL);

    seed_addtime ();
    seed_adduint32 (getpid ());
    seed_adduint32 (getppid ());
    seed_adduint32 (getuid ());
    seed_adduint32 (getgid ());

    seed_addtime ();
    prog = strdup ((x = strrchr (argv[0], '/')) != NULL ?  x + 1 : argv[0]);
    i = check_option (argc, argv);
    argc -= i;
    argv += i;

    if (mode & DAEMON)
    {
        i = fork ();
        if (i == -1)
            err (-1, "could not fork a daemon process");
        if (i > 0)
            return 0;
    }

    time (&t);
    strftime (char_seed, sizeof (char_seed), "%b-%d %Y %T %Z", localtime (&t));
    warnx ("version %s: starting: %s\n", VERSION, char_seed);

    set_timezone ();
    if (debug_level)
        warnx ("TIMEZONE: %s", env_get ("TZ"));

    read_conf (CFGFILE);
    if (!debug_level)
        if ((x = env_get ("DEBUG_LEVEL")))
            debug_level = atol (x);
    warnx ("DEBUG_LEVEL set to `%d'", debug_level);

    if ((x = env_get ("DATALIMIT")))
    {
        struct rlimit r;
        unsigned long dlimit = atol (x);

        if (getrlimit (RLIMIT_DATA,  &r) != 0)
            err (-1, "could not get resource RLIMIT_DATA");

        r.rlim_cur = (dlimit <= r.rlim_max) ? dlimit : r.rlim_max;

        if (setrlimit (RLIMIT_DATA, &r) != 0)
            err (-1, "could not set resource RLIMIT_DATA");

        if (debug_level)
            warnx ("DATALIMIT set to `%ld' bytes", r.rlim_cur);
    }

    if (!(x = env_get ("IP")))
        err (-1, "$IP not set");
    if (!ip4_scan (x, myipincoming))
        err (-1, "could not parse IP address `%s'", x);

    seed_addtime ();
    udp53 = socket_udp ();
    if (udp53 == -1)
        err (-1, "could not open UDP socket");
    if (socket_bind4_reuse (udp53, myipincoming, 53) == -1)
        err (-1, "could not bind UDP socket");

    seed_addtime ();
    tcp53 = socket_tcp ();
    if (tcp53 == -1)
        err (-1, "could not open TCP socket");
    if (socket_bind4_reuse (tcp53, myipincoming, 53) == -1)
        err (-1, "could not bind TCP socket");

    if (mode & DAEMON)
    {
        /* redirect stdout & stderr to a log file */
        redirect_to_log (LOGFILE, STDOUT_FILENO | STDERR_FILENO);

        write_pid (PIDFILE);
    }

    seed_addtime ();
    droproot ();
    if (mode & DAEMON)
        /* crerate a new session & detach from controlling tty */
        if (setsid () < 0)
            err (-1, "could not start a new session for the daemon");

    seed_addtime ();
    socket_tryreservein (udp53, 131072);

    memset (char_seed, 0, sizeof (char_seed));
    for (i = 0, x = (char *)seed; (unsigned)i < sizeof (char_seed); i++, x++)
        char_seed[i] = *x;
    dns_random_init (char_seed);

    if (!(x = env_get ("IPSEND")))
        err (-1, "$IPSEND not set");
    if (!ip4_scan (x, myipoutgoing))
        err (-1, "could not parse IP address `%s'", x);

    if (!(x = env_get ("CACHESIZE")))
        err (-1, "$CACHESIZE not set");
    scan_ulong (x, &cachesize);
    if (!cache_init (cachesize))
        err (-1, "could not allocate `%ld' bytes for cache", cachesize);

    if (env_get ("HIDETTL"))
        response_hidettl ();
    if (env_get ("FORWARDONLY"))
        query_forwardonly ();
    if (env_get ("MERGEQUERIES"))
        dns_enable_merge (log_merge);
    if (!roots_init ())
        err (-1, "could not read servers");
    if (debug_level > 3)
        roots_display();
    if (socket_listen (tcp53, 20) == -1)
        err (-1, "could not listen on TCP socket");
    if (!dbl_init() && debug_level > 1)
        warnx ("could not read dnsbl.cdb");

    doit ();

    return 0;
}
예제 #10
0
파일: dns_transmit.c 프로젝트: pjps/ndjbdns
static int
thisudp (struct dns_transmit *d)
{
    const char *ip = NULL;

    socketfree (d);
    mergefree (d);

    while (d->udploop < 4)
    {
        for (; d->curserver < 16; ++d->curserver)
        {
            ip = d->servers + 4 * d->curserver;
            if (byte_diff (ip, 4, "\0\0\0\0"))
            {
                if (merge_enable && try_merge (d))
                {
                    if (merge_logger)
                        merge_logger (ip, d->qtype, d->query + 14);
                    return 0;
                }

                d->query[2] = dns_random (256);
                d->query[3] = dns_random (256);

                d->s1 = 1 + socket_udp ();
                if (!d->s1)
                {
                    dns_transmit_free (d);
                    return -1;
                }
                if (randombind (d) == -1)
                {
                    dns_transmit_free (d);
                    return -1;
                }

                if (socket_connect4 (d->s1 - 1, ip, 53) == 0)
                {
                    if (send (d->s1 - 1, d->query + 2, d->querylen - 2, 0)
                            == d->querylen - 2)
                    {
                        struct taia now;

                        taia_now (&now);
                        taia_uint (&d->deadline, timeouts[d->udploop]);
                        taia_add (&d->deadline, &d->deadline, &now);
                        d->tcpstate = 0;
                        if (merge_enable)
                            register_inprogress (d);
                        return 0;
                    }
                }
                socketfree (d);
            }
        }

        ++d->udploop;
        d->curserver = 0;
    }

    dns_transmit_free (d);
    return -1;
}
예제 #11
0
파일: srlog2.c 프로젝트: bruceg/srlog2
int cli_main(int argc, char* argv[])
{
  const char* server_name = 0;
  const char* env;

  msg_debug_init();
  encr_start();
  prep_sender();
  service = argv[0];
  if (argc > 1
      && argv[1][0] != '-'
      && argv[1][0] != '+') {
    server_name = argv[1];
    ++argv;
    --argc;
  }
  if (argc > 1)
    load_patterns(argv + 1);

  if (server_name == 0
      && (server_name = getenv("SERVER")) == 0)
    die1(1, "Server address not named on command line nor in $SERVER");
  if (!resolve_ipv4name(server_name, &ip))
    die3(1, "Could not resolve '", server_name, "'");

  brandom_init();
  if ((env = getenv("KEYDIR")) != 0)
    keydir = env;
  load_keys(server_name);

  if ((env = getenv("PORT")) != 0)
    port = strtoul(env, 0, 10);
  if (port == 0)
    port = 11014;
  if ((sock = socket_udp()) == -1)
    die1sys(1, "Could not create UDP socket");
  if (!socket_connect4(sock, &ip, port))
    die1sys(1, "Could not bind socket");
  if (!str_ready(&packet, 65535)
      || !str_ready(&rpacket, 4+4+8+256*5))
    die1(1, "Out of memory");

  getenvu("ACK_TIMEOUT", &ack_timeout);
  getenvu("CID_TIMEOUT", &cid_timeout);
  getenvu("RETRANSMITS", &retransmits);
  getenvu("READWAIT", &readwait);
  getenvu("STARTLINES", &startlines);
  if (getenv("EXITONEOF") != 0)
    exitoneof = 1;

  if (getenv("NOFILES") == 0 && getenv("NOFILE") == 0)
    buffer = buffer_file_init();
  else
    buffer = buffer_nofile_init();

  sig_all_catch(sigfn);
  exitasap = 0;

  mainloop();
  return 0;
}
예제 #12
0
int main(int argc,char **argv)
{
  long long hellopackets;
  long long r;
  long long nextaction;

  signal(SIGPIPE,SIG_IGN);

  if (!argv[0]) die_usage(0);
  for (;;) {
    char *x;
    if (!argv[1]) break;
    if (argv[1][0] != '-') break;
    x = *++argv;
    if (x[0] == '-' && x[1] == 0) break;
    if (x[0] == '-' && x[1] == '-' && x[2] == 0) break;
    while (*++x) {
      if (*x == 'q') { flagverbose = 0; continue; }
      if (*x == 'Q') { flagverbose = 1; continue; }
      if (*x == 'v') { if (flagverbose == 2) flagverbose = 3; else flagverbose = 2; continue; }
      if (*x == 'c') {
        if (x[1]) { keydir = x + 1; break; }
        if (argv[1]) { keydir = *++argv; break; }
      }
      die_usage(0);
    }
  }
  if (!nameparse(servername,*++argv)) die_usage("sname must be at most 255 bytes, at most 63 bytes between dots");
  if (!hexparse(serverlongtermpk,32,*++argv)) die_usage("pk must be exactly 64 hex characters");
  if (!multiipparse(serverip,*++argv)) die_usage("ip must be a comma-separated series of IPv4 addresses");
  if (!portparse(serverport,*++argv)) die_usage("port must be an integer between 0 and 65535");
  if (!hexparse(serverextension,16,*++argv)) die_usage("ext must be exactly 32 hex characters");
  if (!*++argv) die_usage("missing prog");

  for (;;) {
    r = open_read("/dev/null");
    if (r == -1) die_fatal("unable to open /dev/null",0,0);
    if (r > 9) { close(r); break; }
  }

  if (keydir) {
    fdwd = open_cwd();
    if (fdwd == -1) die_fatal("unable to open current working directory",0,0);
    if (chdir(keydir) == -1) die_fatal("unable to change to directory",keydir,0);
    if (load("publickey",clientlongtermpk,sizeof clientlongtermpk) == -1) die_fatal("unable to read public key from",keydir,0);
    if (load(".expertsonly/secretkey",clientlongtermsk,sizeof clientlongtermsk) == -1) die_fatal("unable to read secret key from",keydir,0);
  } else {
    crypto_box_keypair(clientlongtermpk,clientlongtermsk);
  }

  crypto_box_keypair(clientshorttermpk,clientshorttermsk);
  clientshorttermnonce = randommod(281474976710656LL);
  crypto_box_beforenm(clientshortserverlong,serverlongtermpk,clientshorttermsk);
  crypto_box_beforenm(clientlongserverlong,serverlongtermpk,clientlongtermsk);

  udpfd = socket_udp();
  if (udpfd == -1) die_fatal("unable to create socket",0,0);

  for (hellopackets = 0;hellopackets < NUMIP;++hellopackets) {
    recent = nanoseconds();

    /* send a Hello packet: */

    clientextension_init();

    clientshorttermnonce_update();
    byte_copy(nonce,16,"CurveCP-client-H");
    uint64_pack(nonce + 16,clientshorttermnonce);

    byte_copy(packet,8,"QvnQ5XlH");
    byte_copy(packet + 8,16,serverextension);
    byte_copy(packet + 24,16,clientextension);
    byte_copy(packet + 40,32,clientshorttermpk);
    byte_copy(packet + 72,64,allzero);
    byte_copy(packet + 136,8,nonce + 16);
    crypto_box_afternm(text,allzero,96,nonce,clientshortserverlong);
    byte_copy(packet + 144,80,text + 16);

    socket_send(udpfd,packet,224,serverip + 4 * hellopackets,serverport);

    nextaction = recent + hellowait[hellopackets] + randommod(hellowait[hellopackets]);

    for (;;) {
      long long timeout = nextaction - recent;
      if (timeout <= 0) break;
      p[0].fd = udpfd;
      p[0].events = POLLIN;
      if (poll(p,1,timeout / 1000000 + 1) < 0) p[0].revents = 0;

      do { /* try receiving a Cookie packet: */
        if (!p[0].revents) break;
        r = socket_recv(udpfd,packet,sizeof packet,packetip,packetport);
        if (r != 200) break;
        if (!(byte_isequal(packetip,4,serverip + 4 * hellopackets) &
              byte_isequal(packetport,2,serverport) &
              byte_isequal(packet,8,"RL3aNMXK") &
              byte_isequal(packet + 8,16,clientextension) &
              byte_isequal(packet + 24,16,serverextension)
           )) break;
        byte_copy(nonce,8,"CurveCPK");
        byte_copy(nonce + 8,16,packet + 40);
        byte_zero(text,16);
        byte_copy(text + 16,144,packet + 56);
        if (crypto_box_open_afternm(text,text,160,nonce,clientshortserverlong)) break;
        byte_copy(servershorttermpk,32,text + 32);
        byte_copy(servercookie,96,text + 64);
        byte_copy(serverip,4,serverip + 4 * hellopackets);
        goto receivedcookie;
      } while (0);

      recent = nanoseconds();
    }
  }

  errno = ETIMEDOUT; die_fatal("no response from server",0,0);

  receivedcookie:

  crypto_box_beforenm(clientshortservershort,servershorttermpk,clientshorttermsk);

  byte_copy(nonce,8,"CurveCPV");
  if (keydir) {
    if (safenonce(nonce + 8,0) == -1) die_fatal("nonce-generation disaster",0,0);
  } else {
    randombytes(nonce + 8,16);
  }

  byte_zero(text,32);
  byte_copy(text + 32,32,clientshorttermpk);
  crypto_box_afternm(text,text,64,nonce,clientlongserverlong);
  byte_copy(vouch,16,nonce + 8);
  byte_copy(vouch + 16,48,text + 16);

  /* server is responding, so start child: */

  if (open_pipe(tochild) == -1) die_fatal("unable to create pipe",0,0);
  if (open_pipe(fromchild) == -1) die_fatal("unable to create pipe",0,0);

  child = fork();
  if (child == -1) die_fatal("unable to fork",0,0);
  if (child == 0) {
    if (keydir) if (fchdir(fdwd) == -1) die_fatal("unable to chdir to original directory",0,0);
    close(8);
    if (dup(tochild[0]) != 8) die_fatal("unable to dup",0,0);
    close(9);
    if (dup(fromchild[1]) != 9) die_fatal("unable to dup",0,0);
    /* XXX: set up environment variables */
    signal(SIGPIPE,SIG_DFL);
    execvp(*argv,argv);
    die_fatal("unable to run",*argv,0);
  }

  close(fromchild[1]);
  close(tochild[0]);


  for (;;) {
    p[0].fd = udpfd;
    p[0].events = POLLIN;
    p[1].fd = fromchild[0];
    p[1].events = POLLIN;

    if (poll(p,2,-1) < 0) {
      p[0].revents = 0;
      p[1].revents = 0;
    }

    do { /* try receiving a Message packet: */
      if (!p[0].revents) break;
      r = socket_recv(udpfd,packet,sizeof packet,packetip,packetport);
      if (r < 80) break;
      if (r > 1152) break;
      if (r & 15) break;
      packetnonce = uint64_unpack(packet + 40);
      if (flagreceivedmessage && packetnonce <= receivednonce) break;
      if (!(byte_isequal(packetip,4,serverip + 4 * hellopackets) &
            byte_isequal(packetport,2,serverport) &
            byte_isequal(packet,8,"RL3aNMXM") &
            byte_isequal(packet + 8,16,clientextension) &
            byte_isequal(packet + 24,16,serverextension)
         )) break;
      byte_copy(nonce,16,"CurveCP-server-M");
      byte_copy(nonce + 16,8,packet + 40);
      byte_zero(text,16);
      byte_copy(text + 16,r - 48,packet + 48);
      if (crypto_box_open_afternm(text,text,r - 32,nonce,clientshortservershort)) break;

      if (!flagreceivedmessage) {
        flagreceivedmessage = 1;
	randombytes(clientlongtermpk,sizeof clientlongtermpk);
	randombytes(vouch,sizeof vouch);
	randombytes(servername,sizeof servername);
	randombytes(servercookie,sizeof servercookie);
      }

      receivednonce = packetnonce;
      text[31] = (r - 64) >> 4;
      /* child is responsible for reading all data immediately, so we won't block: */
      if (writeall(tochild[1],text + 31,r - 63) == -1) goto done;
    } while (0);

    do { /* try receiving data from child: */
      long long i;
      if (!p[1].revents) break;
      r = read(fromchild[0],childbuf,sizeof childbuf);
      if (r == -1) if (errno == EINTR || errno == EWOULDBLOCK || errno == EAGAIN) break;
      if (r <= 0) goto done;
      childbuflen = r;
      for (i = 0;i < childbuflen;++i) {
	if (childmessagelen < 0) goto done;
	if (childmessagelen >= sizeof childmessage) goto done;
        childmessage[childmessagelen++] = childbuf[i];
	if (childmessage[0] & 128) goto done;
	if (childmessagelen == 1 + 16 * (unsigned long long) childmessage[0]) {
	  clientextension_init();
	  clientshorttermnonce_update();
          uint64_pack(nonce + 16,clientshorttermnonce);
	  if (flagreceivedmessage) {
	    r = childmessagelen - 1;
	    if (r < 16) goto done;
	    if (r > 1088) goto done;
            byte_copy(nonce,16,"CurveCP-client-M");
	    byte_zero(text,32);
	    byte_copy(text + 32,r,childmessage + 1);
	    crypto_box_afternm(text,text,r + 32,nonce,clientshortservershort);
	    byte_copy(packet,8,"QvnQ5XlM");
	    byte_copy(packet + 8,16,serverextension);
	    byte_copy(packet + 24,16,clientextension);
	    byte_copy(packet + 40,32,clientshorttermpk);
	    byte_copy(packet + 72,8,nonce + 16);
	    byte_copy(packet + 80,r + 16,text + 16);
            socket_send(udpfd,packet,r + 96,serverip,serverport);
	  } else {
	    r = childmessagelen - 1;
	    if (r < 16) goto done;
	    if (r > 640) goto done;
	    byte_copy(nonce,16,"CurveCP-client-I");
	    byte_zero(text,32);
	    byte_copy(text + 32,32,clientlongtermpk);
	    byte_copy(text + 64,64,vouch);
	    byte_copy(text + 128,256,servername);
	    byte_copy(text + 384,r,childmessage + 1);
	    crypto_box_afternm(text,text,r + 384,nonce,clientshortservershort);
	    byte_copy(packet,8,"QvnQ5XlI");
	    byte_copy(packet + 8,16,serverextension);
	    byte_copy(packet + 24,16,clientextension);
	    byte_copy(packet + 40,32,clientshorttermpk);
	    byte_copy(packet + 72,96,servercookie);
	    byte_copy(packet + 168,8,nonce + 16);
	    byte_copy(packet + 176,r + 368,text + 16);
            socket_send(udpfd,packet,r + 544,serverip,serverport);
	  }
	  childmessagelen = 0;
	}
      }
    } while (0);
  }


  done:

  do {
    r = waitpid(child,&childstatus,0);
  } while (r == -1 && errno == EINTR);

  if (!WIFEXITED(childstatus)) { errno = 0; die_fatal("process killed by signal",0,0); }
  return WEXITSTATUS(childstatus);
}