pap.c

lwip-1.4.0

  upap_state *u = &upap[unit];

  if (u->us_clientstate == UPAPCS_AUTHREQ) {
    UPAPDEBUG(LOG_ERR, ("PAP authentication failed due to protocol-reject\n"));
    auth_withpeer_fail(unit, PPP_PAP);
  }
  if (u->us_serverstate == UPAPSS_LISTEN) {
    UPAPDEBUG(LOG_ERR, ("PAP authentication of peer failed (protocol-reject)\n"));
    auth_peer_fail(unit, PPP_PAP);
  }
  upap_lowerdown(unit);
}


/*
 * upap_input - Input UPAP packet.
 */
static void
upap_input(int unit, u_char *inpacket, int l)
{
  upap_state *u = &upap[unit];
  u_char *inp;
  u_char code, id;
  int len;

  /*
   * Parse header (code, id and length).
   * If packet too short, drop it.
   */
  inp = inpacket;
  if (l < (int)UPAP_HEADERLEN) {
    UPAPDEBUG(LOG_INFO, ("pap_input: rcvd short header.\n"));
    return;
  }
  GETCHAR(code, inp);
  GETCHAR(id, inp);
  GETSHORT(len, inp);
  if (len < (int)UPAP_HEADERLEN) {
    UPAPDEBUG(LOG_INFO, ("pap_input: rcvd illegal length.\n"));
    return;
  }
  if (len > l) {
    UPAPDEBUG(LOG_INFO, ("pap_input: rcvd short packet.\n"));
    return;
  }
  len -= UPAP_HEADERLEN;

  /*
   * Action depends on code.
   */
  switch (code) {
    case UPAP_AUTHREQ:
      upap_rauthreq(u, inp, id, len);
      break;

    case UPAP_AUTHACK:
      upap_rauthack(u, inp, id, len);
      break;

    case UPAP_AUTHNAK:
      upap_rauthnak(u, inp, id, len);
      break;

    default:        /* XXX Need code reject */
      UPAPDEBUG(LOG_INFO, ("pap_input: UNHANDLED default: code: %d, id: %d, len: %d.\n", code, id, len));
      break;
  }
}


/*
 * upap_rauth - Receive Authenticate.
 */
static void
upap_rauthreq(upap_state *u, u_char *inp, u_char id, int len)
{
  u_char ruserlen, rpasswdlen;
  char *ruser, *rpasswd;
  u_char retcode;
  char *msg;
  int msglen;

  UPAPDEBUG(LOG_INFO, ("pap_rauth: Rcvd id %d.\n", id));

  if (u->us_serverstate < UPAPSS_LISTEN) {
    return;
  }

  /*
   * If we receive a duplicate authenticate-request, we are
   * supposed to return the same status as for the first request.
   */
  if (u->us_serverstate == UPAPSS_OPEN) {
    upap_sresp(u, UPAP_AUTHACK, id, "", 0);  /* return auth-ack */
    return;
  }
  if (u->us_serverstate == UPAPSS_BADAUTH) {
    upap_sresp(u, UPAP_AUTHNAK, id, "", 0);  /* return auth-nak */
    return;
  }

  /*
   * Parse user/passwd.
   */
  if (len < (int)sizeof (u_char)) {
    UPAPDEBUG(LOG_INFO, ("pap_rauth: rcvd short packet.\n"));
    return;
  }
  GETCHAR(ruserlen, inp);
  len -= sizeof (u_char) + ruserlen + sizeof (u_char);
  if (len < 0) {
    UPAPDEBUG(LOG_INFO, ("pap_rauth: rcvd short packet.\n"));
    return;
  }
  ruser = (char *) inp;
  INCPTR(ruserlen, inp);
  GETCHAR(rpasswdlen, inp);
  if (len < rpasswdlen) {
    UPAPDEBUG(LOG_INFO, ("pap_rauth: rcvd short packet.\n"));
    return;
  }
  rpasswd = (char *) inp;

  /*
   * Check the username and password given.
   */
  retcode = check_passwd(u->us_unit, ruser, ruserlen, rpasswd, rpasswdlen, &msg, &msglen);
  /* lwip: currently retcode is always UPAP_AUTHACK */
  BZERO(rpasswd, rpasswdlen);

  upap_sresp(u, retcode, id, msg, msglen);

  if (retcode == UPAP_AUTHACK) {
    u->us_serverstate = UPAPSS_OPEN;
    auth_peer_success(u->us_unit, PPP_PAP, ruser, ruserlen);
  } else {
    u->us_serverstate = UPAPSS_BADAUTH;
    auth_peer_fail(u->us_unit, PPP_PAP);
  }

  if (u->us_reqtimeout > 0) {
    UNTIMEOUT(upap_reqtimeout, u);
  }
}


/*
 * upap_rauthack - Receive Authenticate-Ack.
 */
static void
upap_rauthack(upap_state *u, u_char *inp, int id, int len)
{
  u_char msglen;
  char *msg;

  LWIP_UNUSED_ARG(id);

  UPAPDEBUG(LOG_INFO, ("pap_rauthack: Rcvd id %d s=%d\n", id, u->us_clientstate));

  if (u->us_clientstate != UPAPCS_AUTHREQ) { /* XXX */
    UPAPDEBUG(LOG_INFO, ("pap_rauthack: us_clientstate != UPAPCS_AUTHREQ\n"));
    return;
  }

  /*
   * Parse message.
   */
  if (len < (int)sizeof (u_char)) {
    UPAPDEBUG(LOG_INFO, ("pap_rauthack: ignoring missing msg-length.\n"));
  } else {
    GETCHAR(msglen, inp);
    if (msglen > 0) {
      len -= sizeof (u_char);
      if (len < msglen) {
        UPAPDEBUG(LOG_INFO, ("pap_rauthack: rcvd short packet.\n"));
        return;
      }
      msg = (char *) inp;
      PRINTMSG(msg, msglen);
    }
  }
  UNTIMEOUT(upap_timeout, u);    /* Cancel timeout */
  u->us_clientstate = UPAPCS_OPEN;

  auth_withpeer_success(u->us_unit, PPP_PAP);
}


/*
 * upap_rauthnak - Receive Authenticate-Nak.
 */
static void
upap_rauthnak(upap_state *u, u_char *inp, int id, int len)
{
  u_char msglen;
  char *msg;

  LWIP_UNUSED_ARG(id);

  UPAPDEBUG(LOG_INFO, ("pap_rauthnak: Rcvd id %d s=%d\n", id, u->us_clientstate));

  if (u->us_clientstate != UPAPCS_AUTHREQ) { /* XXX */
    return;
  }

  /*
   * Parse message.
   */
  if (len < sizeof (u_char)) {
    UPAPDEBUG(LOG_INFO, ("pap_rauthnak: ignoring missing msg-length.\n"));
  } else {
    GETCHAR(msglen, inp);
    if(msglen > 0) {
      len -= sizeof (u_char);
      if (len < msglen) {
        UPAPDEBUG(LOG_INFO, ("pap_rauthnak: rcvd short packet.\n"));
        return;
      }
      msg = (char *) inp;
      PRINTMSG(msg, msglen);
    }
  }

  u->us_clientstate = UPAPCS_BADAUTH;

  UPAPDEBUG(LOG_ERR, ("PAP authentication failed\n"));
  auth_withpeer_fail(u->us_unit, PPP_PAP);
}


/*
 * upap_sauthreq - Send an Authenticate-Request.
 */
static void
upap_sauthreq(upap_state *u)
{
  u_char *outp;
  int outlen;

  outlen = UPAP_HEADERLEN + 2 * sizeof (u_char) 
         + u->us_userlen + u->us_passwdlen;
  outp = outpacket_buf[u->us_unit];

  MAKEHEADER(outp, PPP_PAP);

  PUTCHAR(UPAP_AUTHREQ, outp);
  PUTCHAR(++u->us_id, outp);
  PUTSHORT(outlen, outp);
  PUTCHAR(u->us_userlen, outp);
  BCOPY(u->us_user, outp, u->us_userlen);
  INCPTR(u->us_userlen, outp);
  PUTCHAR(u->us_passwdlen, outp);
  BCOPY(u->us_passwd, outp, u->us_passwdlen);

  pppWrite(u->us_unit, outpacket_buf[u->us_unit], outlen + PPP_HDRLEN);

  UPAPDEBUG(LOG_INFO, ("pap_sauth: Sent id %d\n", u->us_id));

  TIMEOUT(upap_timeout, u, u->us_timeouttime);
  ++u->us_transmits;
  u->us_clientstate = UPAPCS_AUTHREQ;
}


/*
 * upap_sresp - Send a response (ack or nak).
 */
static void
upap_sresp(upap_state *u, u_char code, u_char id, char *msg, int msglen)
{
  u_char *outp;
  int outlen;

  outlen = UPAP_HEADERLEN + sizeof (u_char) + msglen;
  outp = outpacket_buf[u->us_unit];
  MAKEHEADER(outp, PPP_PAP);

  PUTCHAR(code, outp);
  PUTCHAR(id, outp);
  PUTSHORT(outlen, outp);
  PUTCHAR(msglen, outp);
  BCOPY(msg, outp, msglen);
  pppWrite(u->us_unit, outpacket_buf[u->us_unit], outlen + PPP_HDRLEN);

  UPAPDEBUG(LOG_INFO, ("pap_sresp: Sent code %d, id %d s=%d\n", code, id, u->us_clientstate));
}

#if PPP_ADDITIONAL_CALLBACKS
static char *upap_codenames[] = {
    "AuthReq", "AuthAck", "AuthNak"
};

/*
 * upap_printpkt - print the contents of a PAP packet.
 */
static int upap_printpkt(
  u_char *p,
  int plen,
  void (*printer) (void *, char *, ...),
  void *arg
)
{
  LWIP_UNUSED_ARG(p);
  LWIP_UNUSED_ARG(plen);
  LWIP_UNUSED_ARG(printer);
  LWIP_UNUSED_ARG(arg);
  return 0;
}
#endif /* PPP_ADDITIONAL_CALLBACKS */

#endif /* PAP_SUPPORT */

#endif /* PPP_SUPPORT */