Official mbed lwIP library (version 1.4.0)

Dependents:   LwIPNetworking NetServicesMin EthernetInterface EthernetInterface_RSF ... more

Legacy Networking Libraries

This is an mbed 2 networking library. For mbed OS 5, lwip has been integrated with built-in networking interfaces. The networking libraries have been revised to better support additional network stacks and thread safety here.

This library is based on the code of lwIP v1.4.0

Copyright (c) 2001, 2002 Swedish Institute of Computer Science.
All rights reserved. 

Redistribution and use in source and binary forms, with or without modification, 
are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice,
   this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.
3. The name of the author may not be used to endorse or promote products
   derived from this software without specific prior written permission. 

THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
OF SUCH DAMAGE.
Revision:
0:51ac1d130fd4
Child:
6:00bf89892c76
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/netif/ppp/pap.c	Fri Jun 22 09:25:39 2012 +0000
@@ -0,0 +1,628 @@
+/*****************************************************************************
+* pap.c - Network Password Authentication Protocol program file.
+*
+* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
+* portions Copyright (c) 1997 by Global Election Systems Inc.
+*
+* The authors hereby grant permission to use, copy, modify, distribute,
+* and license this software and its documentation for any purpose, provided
+* that existing copyright notices are retained in all copies and that this
+* notice and the following disclaimer are included verbatim in any 
+* distributions. No written agreement, license, or royalty fee is required
+* for any of the authorized uses.
+*
+* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
+* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+******************************************************************************
+* REVISION HISTORY
+*
+* 03-01-01 Marc Boucher <marc@mbsi.ca>
+*   Ported to lwIP.
+* 97-12-12 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
+*   Original.
+*****************************************************************************/
+/*
+ * upap.c - User/Password Authentication Protocol.
+ *
+ * Copyright (c) 1989 Carnegie Mellon University.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by Carnegie Mellon University.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#include "lwip/opt.h"
+
+#if PPP_SUPPORT /* don't build if not configured for use in lwipopts.h */
+
+#if PAP_SUPPORT /* don't build if not configured for use in lwipopts.h */
+
+#include "ppp.h"
+#include "pppdebug.h"
+
+#include "auth.h"
+#include "pap.h"
+
+#include <string.h>
+
+#if 0 /* UNUSED */
+static bool hide_password = 1;
+
+/*
+ * Command-line options.
+ */
+static option_t pap_option_list[] = {
+    { "hide-password", o_bool, &hide_password,
+      "Don't output passwords to log", 1 },
+    { "show-password", o_bool, &hide_password,
+      "Show password string in debug log messages", 0 },
+    { "pap-restart", o_int, &upap[0].us_timeouttime,
+      "Set retransmit timeout for PAP" },
+    { "pap-max-authreq", o_int, &upap[0].us_maxtransmits,
+      "Set max number of transmissions for auth-reqs" },
+    { "pap-timeout", o_int, &upap[0].us_reqtimeout,
+      "Set time limit for peer PAP authentication" },
+    { NULL }
+};
+#endif
+
+/*
+ * Protocol entry points.
+ */
+static void upap_init      (int);
+static void upap_lowerup   (int);
+static void upap_lowerdown (int);
+static void upap_input     (int, u_char *, int);
+static void upap_protrej   (int);
+#if PPP_ADDITIONAL_CALLBACKS
+static int  upap_printpkt (u_char *, int, void (*)(void *, char *, ...), void *);
+#endif /* PPP_ADDITIONAL_CALLBACKS */
+
+struct protent pap_protent = {
+  PPP_PAP,
+  upap_init,
+  upap_input,
+  upap_protrej,
+  upap_lowerup,
+  upap_lowerdown,
+  NULL,
+  NULL,
+#if PPP_ADDITIONAL_CALLBACKS
+  upap_printpkt,
+  NULL,
+#endif /* PPP_ADDITIONAL_CALLBACKS */
+  1,
+  "PAP",
+#if PPP_ADDITIONAL_CALLBACKS
+  NULL,
+  NULL,
+  NULL
+#endif /* PPP_ADDITIONAL_CALLBACKS */
+};
+
+upap_state upap[NUM_PPP]; /* UPAP state; one for each unit */
+
+static void upap_timeout   (void *);
+static void upap_reqtimeout(void *);
+static void upap_rauthreq  (upap_state *, u_char *, u_char, int);
+static void upap_rauthack  (upap_state *, u_char *, int, int);
+static void upap_rauthnak  (upap_state *, u_char *, int, int);
+static void upap_sauthreq  (upap_state *);
+static void upap_sresp     (upap_state *, u_char, u_char, char *, int);
+
+
+/*
+ * upap_init - Initialize a UPAP unit.
+ */
+static void
+upap_init(int unit)
+{
+  upap_state *u = &upap[unit];
+
+  UPAPDEBUG(LOG_INFO, ("upap_init: %d\n", unit));
+  u->us_unit         = unit;
+  u->us_user         = NULL;
+  u->us_userlen      = 0;
+  u->us_passwd       = NULL;
+  u->us_passwdlen    = 0;
+  u->us_clientstate  = UPAPCS_INITIAL;
+  u->us_serverstate  = UPAPSS_INITIAL;
+  u->us_id           = 0;
+  u->us_timeouttime  = UPAP_DEFTIMEOUT;
+  u->us_maxtransmits = 10;
+  u->us_reqtimeout   = UPAP_DEFREQTIME;
+}
+
+/*
+ * upap_authwithpeer - Authenticate us with our peer (start client).
+ *
+ * Set new state and send authenticate's.
+ */
+void
+upap_authwithpeer(int unit, char *user, char *password)
+{
+  upap_state *u = &upap[unit];
+
+  UPAPDEBUG(LOG_INFO, ("upap_authwithpeer: %d user=%s password=%s s=%d\n",
+             unit, user, password, u->us_clientstate));
+
+  /* Save the username and password we're given */
+  u->us_user = user;
+  u->us_userlen = (int)strlen(user);
+  u->us_passwd = password;
+  u->us_passwdlen = (int)strlen(password);
+
+  u->us_transmits = 0;
+
+  /* Lower layer up yet? */
+  if (u->us_clientstate == UPAPCS_INITIAL ||
+      u->us_clientstate == UPAPCS_PENDING) {
+    u->us_clientstate = UPAPCS_PENDING;
+    return;
+  }
+
+  upap_sauthreq(u);      /* Start protocol */
+}
+
+
+/*
+ * upap_authpeer - Authenticate our peer (start server).
+ *
+ * Set new state.
+ */
+void
+upap_authpeer(int unit)
+{
+  upap_state *u = &upap[unit];
+
+  /* Lower layer up yet? */
+  if (u->us_serverstate == UPAPSS_INITIAL ||
+      u->us_serverstate == UPAPSS_PENDING) {
+    u->us_serverstate = UPAPSS_PENDING;
+    return;
+  }
+
+  u->us_serverstate = UPAPSS_LISTEN;
+  if (u->us_reqtimeout > 0) {
+    TIMEOUT(upap_reqtimeout, u, u->us_reqtimeout);
+  }
+}
+
+/*
+ * upap_timeout - Retransmission timer for sending auth-reqs expired.
+ */
+static void
+upap_timeout(void *arg)
+{
+  upap_state *u = (upap_state *) arg;
+
+  UPAPDEBUG(LOG_INFO, ("upap_timeout: %d timeout %d expired s=%d\n", 
+        u->us_unit, u->us_timeouttime, u->us_clientstate));
+
+  if (u->us_clientstate != UPAPCS_AUTHREQ) {
+	UPAPDEBUG(LOG_INFO, ("upap_timeout: not in AUTHREQ state!\n"));
+    return;
+  }
+
+  if (u->us_transmits >= u->us_maxtransmits) {
+    /* give up in disgust */
+    UPAPDEBUG(LOG_ERR, ("No response to PAP authenticate-requests\n"));
+    u->us_clientstate = UPAPCS_BADAUTH;
+    auth_withpeer_fail(u->us_unit, PPP_PAP);
+    return;
+  }
+
+  upap_sauthreq(u);    /* Send Authenticate-Request and set upap timeout*/
+}
+
+
+/*
+ * upap_reqtimeout - Give up waiting for the peer to send an auth-req.
+ */
+static void
+upap_reqtimeout(void *arg)
+{
+  upap_state *u = (upap_state *) arg;
+
+  if (u->us_serverstate != UPAPSS_LISTEN) {
+    return; /* huh?? */
+  }
+
+  auth_peer_fail(u->us_unit, PPP_PAP);
+  u->us_serverstate = UPAPSS_BADAUTH;
+}
+
+
+/*
+ * upap_lowerup - The lower layer is up.
+ *
+ * Start authenticating if pending.
+ */
+static void
+upap_lowerup(int unit)
+{
+  upap_state *u = &upap[unit];
+
+  UPAPDEBUG(LOG_INFO, ("upap_lowerup: init %d clientstate s=%d\n", unit, u->us_clientstate));
+
+  if (u->us_clientstate == UPAPCS_INITIAL) {
+    u->us_clientstate = UPAPCS_CLOSED;
+  } else if (u->us_clientstate == UPAPCS_PENDING) {
+    upap_sauthreq(u);  /* send an auth-request */
+    /* now client state is UPAPCS__AUTHREQ */
+  }
+
+  if (u->us_serverstate == UPAPSS_INITIAL) {
+    u->us_serverstate = UPAPSS_CLOSED;
+  } else if (u->us_serverstate == UPAPSS_PENDING) {
+    u->us_serverstate = UPAPSS_LISTEN;
+    if (u->us_reqtimeout > 0) {
+      TIMEOUT(upap_reqtimeout, u, u->us_reqtimeout);
+    }
+  }
+}
+
+
+/*
+ * upap_lowerdown - The lower layer is down.
+ *
+ * Cancel all timeouts.
+ */
+static void
+upap_lowerdown(int unit)
+{
+  upap_state *u = &upap[unit];
+
+  UPAPDEBUG(LOG_INFO, ("upap_lowerdown: %d s=%d\n", unit, u->us_clientstate));
+
+  if (u->us_clientstate == UPAPCS_AUTHREQ) { /* Timeout pending? */
+    UNTIMEOUT(upap_timeout, u);    /* Cancel timeout */
+  }
+  if (u->us_serverstate == UPAPSS_LISTEN && u->us_reqtimeout > 0) {
+    UNTIMEOUT(upap_reqtimeout, u);
+  }
+
+  u->us_clientstate = UPAPCS_INITIAL;
+  u->us_serverstate = UPAPSS_INITIAL;
+}
+
+
+/*
+ * upap_protrej - Peer doesn't speak this protocol.
+ *
+ * This shouldn't happen.  In any case, pretend lower layer went down.
+ */
+static void
+upap_protrej(int unit)
+{
+  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 */