/****************************************************************************
 *
 * Copyright 2016 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/

/** In contrast to pppd 2.3.1, DNS support has been added, proxy-ARP and
    dial-on-demand has been stripped. */
/*****************************************************************************
* ipcp.c - Network PPP IP Control 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.
* 97-12-08 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
*   Original.
*****************************************************************************/
/*
 * ipcp.c - PPP IP Control 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 <net/lwip/opt.h>

#if PPP_SUPPORT					/* don't build if not configured for use in lwipopts.h */

#include "ppp_impl.h"
#include "pppdebug.h"

#include "auth.h"
#include "fsm.h"
#include "vj.h"
#include "ipcp.h"

#include <net/lwip/inet.h>

#include <string.h>

/* #define OLD_CI_ADDRS 1 *//* Support deprecated address negotiation. */

/* global vars */
ipcp_options ipcp_wantoptions[NUM_PPP];	/* Options that we want to request */
ipcp_options ipcp_gotoptions[NUM_PPP];	/* Options that peer ack'd */
ipcp_options ipcp_allowoptions[NUM_PPP];	/* Options we allow peer to request */
ipcp_options ipcp_hisoptions[NUM_PPP];	/* Options that we ack'd */

/* local vars */
static int default_route_set[NUM_PPP];	/* Have set up a default route */
static int cis_received[NUM_PPP];	/* # Conf-Reqs received */

/*
 * Callbacks for fsm code.  (CI = Configuration Information)
 */
static void ipcp_resetci(fsm *);	/* Reset our CI */
static int ipcp_cilen(fsm *);	/* Return length of our CI */
static void ipcp_addci(fsm *, u_char *, int *);	/* Add our CI */
static int ipcp_ackci(fsm *, u_char *, int);	/* Peer ack'd our CI */
static int ipcp_nakci(fsm *, u_char *, int);	/* Peer nak'd our CI */
static int ipcp_rejci(fsm *, u_char *, int);	/* Peer rej'd our CI */
static int ipcp_reqci(fsm *, u_char *, int *, int);	/* Rcv CI */
static void ipcp_up(fsm *);		/* We're UP */
static void ipcp_down(fsm *);	/* We're DOWN */
#if PPP_ADDITIONAL_CALLBACKS
static void ipcp_script(fsm *, char *);	/* Run an up/down script */
#endif
static void ipcp_finished(fsm *);	/* Don't need lower layer */

fsm ipcp_fsm[NUM_PPP];			/* IPCP fsm structure */

static fsm_callbacks ipcp_callbacks =	/* IPCP callback routines */
{
	ipcp_resetci,				/* Reset our Configuration Information */
	ipcp_cilen,					/* Length of our Configuration Information */
	ipcp_addci,					/* Add our Configuration Information */
	ipcp_ackci,					/* ACK our Configuration Information */
	ipcp_nakci,					/* NAK our Configuration Information */
	ipcp_rejci,					/* Reject our Configuration Information */
	ipcp_reqci,					/* Request peer's Configuration Information */
	ipcp_up,					/* Called when fsm reaches LS_OPENED state */
	ipcp_down,					/* Called when fsm leaves LS_OPENED state */
	NULL,						/* Called when we want the lower layer up */
	ipcp_finished,				/* Called when we want the lower layer down */
	NULL,						/* Called when Protocol-Reject received */
	NULL,						/* Retransmission is necessary */
	NULL,						/* Called to handle protocol-specific codes */
	"IPCP"						/* String name of protocol */
};

/*
 * Protocol entry points from main code.
 */
static void ipcp_init(int);
static void ipcp_open(int);
static void ipcp_close(int, char *);
static void ipcp_lowerup(int);
static void ipcp_lowerdown(int);
static void ipcp_input(int, u_char *, int);
static void ipcp_protrej(int);

struct protent ipcp_protent = {
	PPP_IPCP,
	ipcp_init,
	ipcp_input,
	ipcp_protrej,
	ipcp_lowerup,
	ipcp_lowerdown,
	ipcp_open,
	ipcp_close,
#if PPP_ADDITIONAL_CALLBACKS
	ipcp_printpkt,
	NULL,
#endif							/* PPP_ADDITIONAL_CALLBACKS */
	1,
	"IPCP",
#if PPP_ADDITIONAL_CALLBACKS
	ip_check_options,
	NULL,
	ip_active_pkt
#endif							/* PPP_ADDITIONAL_CALLBACKS */
};

static void ipcp_clear_addrs(int);

/*
 * Lengths of configuration options.
 */
#define CILEN_VOID     2
#define CILEN_COMPRESS 4		/* min length for compression protocol opt. */
#define CILEN_VJ       6		/* length for RFC1332 Van-Jacobson opt. */
#define CILEN_ADDR     6		/* new-style single address option */
#define CILEN_ADDRS    10		/* old-style dual address option */

#define CODENAME(x) ((x) == CONFACK ? "ACK" : \
		(x) == CONFNAK ? "NAK" : "REJ")

/*
 * ipcp_init - Initialize IPCP.
 */
static void ipcp_init(int unit)
{
	fsm *f = &ipcp_fsm[unit];
	ipcp_options *wo = &ipcp_wantoptions[unit];
	ipcp_options *ao = &ipcp_allowoptions[unit];

	f->unit = unit;
	f->protocol = PPP_IPCP;
	f->callbacks = &ipcp_callbacks;
	fsm_init(&ipcp_fsm[unit]);

	memset(wo, 0, sizeof(*wo));
	memset(ao, 0, sizeof(*ao));

	wo->neg_addr = 1;
	wo->ouraddr = 0;
#if VJ_SUPPORT
	wo->neg_vj = 1;
#else							/* VJ_SUPPORT */
	wo->neg_vj = 0;
#endif							/* VJ_SUPPORT */
	wo->vj_protocol = IPCP_VJ_COMP;
	wo->maxslotindex = MAX_SLOTS - 1;
	wo->cflag = 0;
	wo->default_route = 1;

	ao->neg_addr = 1;
#if VJ_SUPPORT
	ao->neg_vj = 1;
#else							/* VJ_SUPPORT */
	ao->neg_vj = 0;
#endif							/* VJ_SUPPORT */
	ao->maxslotindex = MAX_SLOTS - 1;
	ao->cflag = 1;
	ao->default_route = 1;
}

/*
 * ipcp_open - IPCP is allowed to come up.
 */
static void ipcp_open(int unit)
{
	fsm_open(&ipcp_fsm[unit]);
}

/*
 * ipcp_close - Take IPCP down.
 */
static void ipcp_close(int unit, char *reason)
{
	fsm_close(&ipcp_fsm[unit], reason);
}

/*
 * ipcp_lowerup - The lower layer is up.
 */
static void ipcp_lowerup(int unit)
{
	fsm_lowerup(&ipcp_fsm[unit]);
}

/*
 * ipcp_lowerdown - The lower layer is down.
 */
static void ipcp_lowerdown(int unit)
{
	fsm_lowerdown(&ipcp_fsm[unit]);
}

/*
 * ipcp_input - Input IPCP packet.
 */
static void ipcp_input(int unit, u_char *p, int len)
{
	fsm_input(&ipcp_fsm[unit], p, len);
}

/*
 * ipcp_protrej - A Protocol-Reject was received for IPCP.
 *
 * Pretend the lower layer went down, so we shut up.
 */
static void ipcp_protrej(int unit)
{
	fsm_lowerdown(&ipcp_fsm[unit]);
}

/*
 * ipcp_resetci - Reset our CI.
 */
static void ipcp_resetci(fsm *f)
{
	ipcp_options *wo = &ipcp_wantoptions[f->unit];

	wo->req_addr = wo->neg_addr && ipcp_allowoptions[f->unit].neg_addr;
	if (wo->ouraddr == 0) {
		wo->accept_local = 1;
	}
	if (wo->hisaddr == 0) {
		wo->accept_remote = 1;
	}
	/* Request DNS addresses from the peer */
	wo->req_dns1 = ppp_settings.usepeerdns;
	wo->req_dns2 = ppp_settings.usepeerdns;
	ipcp_gotoptions[f->unit] = *wo;
	cis_received[f->unit] = 0;
}

/*
 * ipcp_cilen - Return length of our CI.
 */
static int ipcp_cilen(fsm *f)
{
	ipcp_options *go = &ipcp_gotoptions[f->unit];
	ipcp_options *wo = &ipcp_wantoptions[f->unit];
	ipcp_options *ho = &ipcp_hisoptions[f->unit];

#define LENCIVJ(neg, old)   (neg ? (old ? CILEN_COMPRESS : CILEN_VJ) : 0)
#define LENCIADDR(neg, old) (neg ? (old ? CILEN_ADDRS : CILEN_ADDR) : 0)
#define LENCIDNS(neg)       (neg ? (CILEN_ADDR) : 0)

	/*
	 * First see if we want to change our options to the old
	 * forms because we have received old forms from the peer.
	 */
	if (wo->neg_addr && !go->neg_addr && !go->old_addrs) {
		/* use the old style of address negotiation */
		go->neg_addr = 1;
		go->old_addrs = 1;
	}
	if (wo->neg_vj && !go->neg_vj && !go->old_vj) {
		/* try an older style of VJ negotiation */
		if (cis_received[f->unit] == 0) {
			/* keep trying the new style until we see some CI from the peer */
			go->neg_vj = 1;
		} else {
			/* use the old style only if the peer did */
			if (ho->neg_vj && ho->old_vj) {
				go->neg_vj = 1;
				go->old_vj = 1;
				go->vj_protocol = ho->vj_protocol;
			}
		}
	}

	return (LENCIADDR(go->neg_addr, go->old_addrs) + LENCIVJ(go->neg_vj, go->old_vj) + LENCIDNS(go->req_dns1) + LENCIDNS(go->req_dns2));
}

/*
 * ipcp_addci - Add our desired CIs to a packet.
 */
static void ipcp_addci(fsm *f, u_char *ucp, int *lenp)
{
	ipcp_options *go = &ipcp_gotoptions[f->unit];
	int len = *lenp;

#define ADDCIVJ(opt, neg, val, old, maxslotindex, cflag) \
	if (neg) { \
		int vjlen = old ? CILEN_COMPRESS : CILEN_VJ; \
		if (len >= vjlen) { \
			PUTCHAR(opt, ucp); \
			PUTCHAR(vjlen, ucp); \
			PUTSHORT(val, ucp); \
			if (!old) { \
				PUTCHAR(maxslotindex, ucp); \
				PUTCHAR(cflag, ucp); \
			} \
			len -= vjlen; \
		} else { \
			neg = 0; \
		} \
	}

#define ADDCIADDR(opt, neg, old, val1, val2) \
		if (neg) { \
			int addrlen = (old ? CILEN_ADDRS : CILEN_ADDR); \
			if (len >= addrlen) { \
				u32_t l; \
				PUTCHAR(opt, ucp); \
				PUTCHAR(addrlen, ucp); \
				l = ntohl(val1); \
				PUTLONG(l, ucp); \
				if (old) { \
					l = ntohl(val2); \
					PUTLONG(l, ucp); \
				} \
				len -= addrlen; \
			} else { \
				neg = 0; \
			} \
		}

#define ADDCIDNS(opt, neg, addr) \
		if (neg) { \
			if (len >= CILEN_ADDR) { \
				u32_t l; \
				PUTCHAR(opt, ucp); \
				PUTCHAR(CILEN_ADDR, ucp); \
				l = ntohl(addr); \
				PUTLONG(l, ucp); \
				len -= CILEN_ADDR; \
			} else { \
				neg = 0; \
			} \
		}

	ADDCIADDR((go->old_addrs ? CI_ADDRS : CI_ADDR), go->neg_addr, go->old_addrs, go->ouraddr, go->hisaddr);

	ADDCIVJ(CI_COMPRESSTYPE, go->neg_vj, go->vj_protocol, go->old_vj, go->maxslotindex, go->cflag);

	ADDCIDNS(CI_MS_DNS1, go->req_dns1, go->dnsaddr[0]);

	ADDCIDNS(CI_MS_DNS2, go->req_dns2, go->dnsaddr[1]);

	*lenp -= len;
}

/*
 * ipcp_ackci - Ack our CIs.
 *
 * Returns:
 *  0 - Ack was bad.
 *  1 - Ack was good.
 */
static int ipcp_ackci(fsm *f, u_char *p, int len)
{
	ipcp_options *go = &ipcp_gotoptions[f->unit];
	u_short cilen, citype, cishort;
	u32_t cilong;
	u_char cimaxslotindex, cicflag;

	/*
	 * CIs must be in exactly the same order that we sent...
	 * Check packet length and CI length at each step.
	 * If we find any deviations, then this packet is bad.
	 */

#define ACKCIVJ(opt, neg, val, old, maxslotindex, cflag) \
		if (neg) { \
			int vjlen = old ? CILEN_COMPRESS : CILEN_VJ; \
			if ((len -= vjlen) < 0) { \
				goto bad; \
			} \
			GETCHAR(citype, p); \
			GETCHAR(cilen, p); \
			if (cilen != vjlen || \
					citype != opt) { \
				goto bad; \
			} \
			GETSHORT(cishort, p); \
			if (cishort != val) { \
				goto bad; \
			} \
			if (!old) { \
				GETCHAR(cimaxslotindex, p); \
				if (cimaxslotindex != maxslotindex) { \
					goto bad; \
				} \
				GETCHAR(cicflag, p); \
				if (cicflag != cflag) { \
					goto bad; \
				} \
			} \
		}

#define ACKCIADDR(opt, neg, old, val1, val2) \
		if (neg) { \
			int addrlen = (old ? CILEN_ADDRS : CILEN_ADDR); \
			u32_t l; \
			if ((len -= addrlen) < 0) { \
				goto bad; \
			} \
			GETCHAR(citype, p); \
			GETCHAR(cilen, p); \
			if (cilen != addrlen || \
					citype != opt) { \
				goto bad; \
			} \
			GETLONG(l, p); \
			cilong = htonl(l); \
			if (val1 != cilong) { \
				goto bad; \
			} \
			if (old) { \
				GETLONG(l, p); \
				cilong = htonl(l); \
				if (val2 != cilong) { \
					goto bad; \
				} \
			} \
		}

#define ACKCIDNS(opt, neg, addr) \
		if (neg) { \
			u32_t l; \
			if ((len -= CILEN_ADDR) < 0) { \
				goto bad; \
			} \
			GETCHAR(citype, p); \
			GETCHAR(cilen, p); \
			if (cilen != CILEN_ADDR || \
					citype != opt) { \
				goto bad; \
			} \
			GETLONG(l, p); \
			cilong = htonl(l); \
			if (addr != cilong) { \
				goto bad; \
			} \
		}

	ACKCIADDR((go->old_addrs ? CI_ADDRS : CI_ADDR), go->neg_addr, go->old_addrs, go->ouraddr, go->hisaddr);

	ACKCIVJ(CI_COMPRESSTYPE, go->neg_vj, go->vj_protocol, go->old_vj, go->maxslotindex, go->cflag);

	ACKCIDNS(CI_MS_DNS1, go->req_dns1, go->dnsaddr[0]);

	ACKCIDNS(CI_MS_DNS2, go->req_dns2, go->dnsaddr[1]);

	/*
	 * If there are any remaining CIs, then this packet is bad.
	 */
	if (len != 0) {
		goto bad;
	}
	return (1);

bad:
	IPCPDEBUG(LOG_INFO, ("ipcp_ackci: received bad Ack!\n"));
	return (0);
}

/*
 * ipcp_nakci - Peer has sent a NAK for some of our CIs.
 * This should not modify any state if the Nak is bad
 * or if IPCP is in the LS_OPENED state.
 *
 * Returns:
 *  0 - Nak was bad.
 *  1 - Nak was good.
 */
static int ipcp_nakci(fsm *f, u_char *p, int len)
{
	ipcp_options *go = &ipcp_gotoptions[f->unit];
	u_char cimaxslotindex, cicflag;
	u_char citype, cilen, *next;
	u_short cishort;
	u32_t ciaddr1, ciaddr2, l, cidnsaddr;
	ipcp_options no;			/* options we've seen Naks for */
	ipcp_options try;			/* options to request next time */

	BZERO(&no, sizeof(no));
	try = *go;

	/*
	 * Any Nak'd CIs must be in exactly the same order that we sent.
	 * Check packet length and CI length at each step.
	 * If we find any deviations, then this packet is bad.
	 */
#define NAKCIADDR(opt, neg, old, code) \
		if (go->neg && \
				len >= (cilen = (old ? CILEN_ADDRS : CILEN_ADDR)) && \
				p[1] == cilen && \
				p[0] == opt) { \
			len -= cilen; \
			INCPTR(2, p); \
			GETLONG(l, p); \
			ciaddr1 = htonl(l); \
			if (old) { \
				GETLONG(l, p); \
				ciaddr2 = htonl(l); \
				no.old_addrs = 1; \
			} else { \
				ciaddr2 = 0; \
			} \
			no.neg = 1; \
			code \
		}

#define NAKCIVJ(opt, neg, code) \
		if (go->neg && \
				((cilen = p[1]) == CILEN_COMPRESS || cilen == CILEN_VJ) && \
				len >= cilen && \
				p[0] == opt) { \
			len -= cilen; \
			INCPTR(2, p); \
			GETSHORT(cishort, p); \
			no.neg = 1; \
			code \
		}

#define NAKCIDNS(opt, neg, code) \
		if (go->neg && \
				((cilen = p[1]) == CILEN_ADDR) && \
				len >= cilen && \
				p[0] == opt) { \
			len -= cilen; \
			INCPTR(2, p); \
			GETLONG(l, p); \
			cidnsaddr = htonl(l); \
			no.neg = 1; \
			code \
		}

	/*
	 * Accept the peer's idea of {our,his} address, if different
	 * from our idea, only if the accept_{local,remote} flag is set.
	 */
	NAKCIADDR((go->old_addrs ? CI_ADDRS : CI_ADDR), neg_addr, go->old_addrs, if (go->accept_local && ciaddr1) {	/* Do we know our address? */
	try.ouraddr = ciaddr1;
	IPCPDEBUG(LOG_INFO, ("local IP address %s\n", inet_ntoa(ciaddr1)));
	}
	if (go->accept_remote && ciaddr2) {	/* Does he know his? */
	try.hisaddr = ciaddr2;
	IPCPDEBUG(LOG_INFO, ("remote IP address %s\n", inet_ntoa(ciaddr2)));
	}
			 ) ;

	/*
	 * Accept the peer's value of maxslotindex provided that it
	 * is less than what we asked for.  Turn off slot-ID compression
	 * if the peer wants.  Send old-style compress-type option if
	 * the peer wants.
	 */
	NAKCIVJ(CI_COMPRESSTYPE, neg_vj, if (cilen == CILEN_VJ) {
	GETCHAR(cimaxslotindex, p);
		GETCHAR(cicflag, p);
		if (cishort == IPCP_VJ_COMP) {
			try.old_vj = 0;
			if (cimaxslotindex < go->maxslotindex) {
				try.maxslotindex = cimaxslotindex;
			}
			if (!cicflag) {
				try.cflag = 0;
			}
		} else {
			try.neg_vj = 0;
		}
	} else {
		if (cishort == IPCP_VJ_COMP || cishort == IPCP_VJ_COMP_OLD) {
			try.old_vj = 1;
			try.vj_protocol = cishort;
		} else {
			try.neg_vj = 0;
		}
	}
		   ) ;

	NAKCIDNS(CI_MS_DNS1, req_dns1, try.dnsaddr[0] = cidnsaddr; IPCPDEBUG(LOG_INFO, ("primary DNS address %s\n", inet_ntoa(cidnsaddr))););

	NAKCIDNS(CI_MS_DNS2, req_dns2, try.dnsaddr[1] = cidnsaddr; IPCPDEBUG(LOG_INFO, ("secondary DNS address %s\n", inet_ntoa(cidnsaddr))););

	/*
	 * There may be remaining CIs, if the peer is requesting negotiation
	 * on an option that we didn't include in our request packet.
	 * If they want to negotiate about IP addresses, we comply.
	 * If they want us to ask for compression, we refuse.
	 */
	while (len > CILEN_VOID) {
		GETCHAR(citype, p);
		GETCHAR(cilen, p);
		if ((len -= cilen) < 0) {
			goto bad;
		}
		next = p + cilen - 2;

		switch (citype) {
		case CI_COMPRESSTYPE:
			if (go->neg_vj || no.neg_vj || (cilen != CILEN_VJ && cilen != CILEN_COMPRESS)) {
				goto bad;
			}
			no.neg_vj = 1;
			break;
		case CI_ADDRS:
			if ((go->neg_addr && go->old_addrs) || no.old_addrs || cilen != CILEN_ADDRS) {
				goto bad;
			}
			try.neg_addr = 1;
			try.old_addrs = 1;
			GETLONG(l, p);
			ciaddr1 = htonl(l);
			if (ciaddr1 && go->accept_local) {
				try.ouraddr = ciaddr1;
			}
			GETLONG(l, p);
			ciaddr2 = htonl(l);
			if (ciaddr2 && go->accept_remote) {
				try.hisaddr = ciaddr2;
			}
			no.old_addrs = 1;
			break;
		case CI_ADDR:
			if (go->neg_addr || no.neg_addr || cilen != CILEN_ADDR) {
				goto bad;
			}
			try.old_addrs = 0;
			GETLONG(l, p);
			ciaddr1 = htonl(l);
			if (ciaddr1 && go->accept_local) {
				try.ouraddr = ciaddr1;
			}
			if (try.ouraddr != 0) {
				try.neg_addr = 1;
			}
			no.neg_addr = 1;
			break;
		}
		p = next;
	}

	/* If there is still anything left, this packet is bad. */
	if (len != 0) {
		goto bad;
	}

	/*
	 * OK, the Nak is good.  Now we can update state.
	 */
	if (f->state != LS_OPENED) {
		*go = try;
	}

	return 1;

bad:
	IPCPDEBUG(LOG_INFO, ("ipcp_nakci: received bad Nak!\n"));
	return 0;
}

/*
 * ipcp_rejci - Reject some of our CIs.
 */
static int ipcp_rejci(fsm *f, u_char *p, int len)
{
	ipcp_options *go = &ipcp_gotoptions[f->unit];
	u_char cimaxslotindex, ciflag, cilen;
	u_short cishort;
	u32_t cilong;
	ipcp_options try;			/* options to request next time */

	try = *go;
	/*
	 * Any Rejected CIs must be in exactly the same order that we sent.
	 * Check packet length and CI length at each step.
	 * If we find any deviations, then this packet is bad.
	 */
#define REJCIADDR(opt, neg, old, val1, val2) \
		if (go->neg && \
				len >= (cilen = old ? CILEN_ADDRS : CILEN_ADDR) && \
				p[1] == cilen && \
				p[0] == opt) { \
			u32_t l; \
			len -= cilen; \
			INCPTR(2, p); \
			GETLONG(l, p); \
			cilong = htonl(l); \
	/* Check rejected value. */ \
if (cilong != val1) { \
	goto bad; \
} \
if (old) { \
	GETLONG(l, p); \
	cilong = htonl(l); \
	/* Check rejected value. */ \
if (cilong != val2) { \
	goto bad; \
} \
	} \
try.neg = 0; \
}

#define REJCIVJ(opt, neg, val, old, maxslot, cflag) \
	if (go->neg && \
			p[1] == (old ? CILEN_COMPRESS : CILEN_VJ) && \
			len >= p[1] && \
			p[0] == opt) { \
		len -= p[1]; \
		INCPTR(2, p); \
		GETSHORT(cishort, p); \
/* Check rejected value. */  \
if (cishort != val) { \
	goto bad; \
} \
if (!old) { \
	GETCHAR(cimaxslotindex, p); \
	if (cimaxslotindex != maxslot) { \
		goto bad; \
	} \
	GETCHAR(ciflag, p); \
	if (ciflag != cflag) { \
		goto bad; \
	} \
} \
try.neg = 0; \
}

#define REJCIDNS(opt, neg, dnsaddr) \
	if (go->neg && \
			((cilen = p[1]) == CILEN_ADDR) && \
			len >= cilen && \
			p[0] == opt) { \
		u32_t l; \
		len -= cilen; \
		INCPTR(2, p); \
		GETLONG(l, p); \
		cilong = htonl(l); \
/* Check rejected value. */ \
if (cilong != dnsaddr) { \
	goto bad; \
} \
try.neg = 0; \
}

	REJCIADDR((go->old_addrs ? CI_ADDRS : CI_ADDR), neg_addr, go->old_addrs, go->ouraddr, go->hisaddr);

	REJCIVJ(CI_COMPRESSTYPE, neg_vj, go->vj_protocol, go->old_vj, go->maxslotindex, go->cflag);

	REJCIDNS(CI_MS_DNS1, req_dns1, go->dnsaddr[0]);

	REJCIDNS(CI_MS_DNS2, req_dns2, go->dnsaddr[1]);

	/*
	 * If there are any remaining CIs, then this packet is bad.
	 */
	if (len != 0) {
		goto bad;
	}
	/*
	 * Now we can update state.
	 */
	if (f->state != LS_OPENED) {
		*go = try;
	}
	return 1;

bad:
	IPCPDEBUG(LOG_INFO, ("ipcp_rejci: received bad Reject!\n"));
	return 0;
}

/*
 * ipcp_reqci - Check the peer's requested CIs and send appropriate response.
 *
 * Returns: CONFACK, CONFNAK or CONFREJ and input packet modified
 * appropriately.  If reject_if_disagree is non-zero, doesn't return
 * CONFNAK; returns CONFREJ if it can't return CONFACK.
 */
static int ipcp_reqci(fsm *f, u_char *inp /* Requested CIs */ ,
					  int *len /* Length of requested CIs */ , int reject_if_disagree)
{
	ipcp_options *wo = &ipcp_wantoptions[f->unit];
	ipcp_options *ho = &ipcp_hisoptions[f->unit];
	ipcp_options *ao = &ipcp_allowoptions[f->unit];
#ifdef OLD_CI_ADDRS
	ipcp_options *go = &ipcp_gotoptions[f->unit];
#endif
	u_char *cip, *next;			/* Pointer to current and next CIs */
	u_short cilen, citype;		/* Parsed len, type */
	u_short cishort;			/* Parsed short value */
	u32_t tl, ciaddr1;			/* Parsed address values */
#ifdef OLD_CI_ADDRS
	u32_t ciaddr2;				/* Parsed address values */
#endif
	int rc = CONFACK;			/* Final packet return code */
	int orc;					/* Individual option return code */
	u_char *p;					/* Pointer to next char to parse */
	u_char *ucp = inp;			/* Pointer to current output char */
	int l = *len;				/* Length left */
	u_char maxslotindex, cflag;
	int d;

	cis_received[f->unit] = 1;

	/*
	 * Reset all his options.
	 */
	BZERO(ho, sizeof(*ho));

	/*
	 * Process all his options.
	 */
	next = inp;
	while (l) {
		orc = CONFACK;			/* Assume success */
		cip = p = next;			/* Remember begining of CI */
		if (l < 2 ||			/* Not enough data for CI header or */
			p[1] < 2 ||			/*  CI length too small or */
			p[1] > l) {			/*  CI length too big? */
			IPCPDEBUG(LOG_INFO, ("ipcp_reqci: bad CI length!\n"));
			orc = CONFREJ;		/* Reject bad CI */
			cilen = (u_short) l;	/* Reject till end of packet */
			l = 0;				/* Don't loop again */
			goto endswitch;
		}
		GETCHAR(citype, p);		/* Parse CI type */
		GETCHAR(cilen, p);		/* Parse CI length */
		l -= cilen;				/* Adjust remaining length */
		next += cilen;			/* Step to next CI */

		switch (citype) {		/* Check CI type */
#ifdef OLD_CI_ADDRS				/* Need to save space... */
		case CI_ADDRS:
			IPCPDEBUG(LOG_INFO, ("ipcp_reqci: received ADDRS\n"));
			if (!ao->neg_addr || cilen != CILEN_ADDRS) {	/* Check CI length */
				orc = CONFREJ;	/* Reject CI */
				break;
			}

			/*
			 * If he has no address, or if we both have his address but
			 * disagree about it, then NAK it with our idea.
			 * In particular, if we don't know his address, but he does,
			 * then accept it.
			 */
			GETLONG(tl, p);		/* Parse source address (his) */
			ciaddr1 = htonl(tl);
			IPCPDEBUG(LOG_INFO, ("his addr %s\n", inet_ntoa(ciaddr1)));
			if (ciaddr1 != wo->hisaddr && (ciaddr1 == 0 || !wo->accept_remote)) {
				orc = CONFNAK;
				if (!reject_if_disagree) {
					DECPTR(sizeof(u32_t), p);
					tl = ntohl(wo->hisaddr);
					PUTLONG(tl, p);
				}
			} else if (ciaddr1 == 0 && wo->hisaddr == 0) {
				/*
				 * If neither we nor he knows his address, reject the option.
				 */
				orc = CONFREJ;
				wo->req_addr = 0;	/* don't NAK with 0.0.0.0 later */
				break;
			}

			/*
			 * If he doesn't know our address, or if we both have our address
			 * but disagree about it, then NAK it with our idea.
			 */
			GETLONG(tl, p);		/* Parse desination address (ours) */
			ciaddr2 = htonl(tl);
			IPCPDEBUG(LOG_INFO, ("our addr %s\n", inet_ntoa(ciaddr2)));
			if (ciaddr2 != wo->ouraddr) {
				if (ciaddr2 == 0 || !wo->accept_local) {
					orc = CONFNAK;
					if (!reject_if_disagree) {
						DECPTR(sizeof(u32_t), p);
						tl = ntohl(wo->ouraddr);
						PUTLONG(tl, p);
					}
				} else {
					go->ouraddr = ciaddr2;	/* accept peer's idea */
				}
			}

			ho->neg_addr = 1;
			ho->old_addrs = 1;
			ho->hisaddr = ciaddr1;
			ho->ouraddr = ciaddr2;
			break;
#endif

		case CI_ADDR:
			if (!ao->neg_addr) {
				IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Reject ADDR not allowed\n"));
				orc = CONFREJ;	/* Reject CI */
				break;
			} else if (cilen != CILEN_ADDR) {	/* Check CI length */
				IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Reject ADDR bad len\n"));
				orc = CONFREJ;	/* Reject CI */
				break;
			}

			/*
			 * If he has no address, or if we both have his address but
			 * disagree about it, then NAK it with our idea.
			 * In particular, if we don't know his address, but he does,
			 * then accept it.
			 */
			GETLONG(tl, p);		/* Parse source address (his) */
			ciaddr1 = htonl(tl);
			if (ciaddr1 != wo->hisaddr && (ciaddr1 == 0 || !wo->accept_remote)) {
				orc = CONFNAK;
				if (!reject_if_disagree) {
					DECPTR(sizeof(u32_t), p);
					tl = ntohl(wo->hisaddr);
					PUTLONG(tl, p);
				}
				IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Nak ADDR %s\n", inet_ntoa(ciaddr1)));
			} else if (ciaddr1 == 0 && wo->hisaddr == 0) {
				/*
				 * Don't ACK an address of 0.0.0.0 - reject it instead.
				 */
				IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Reject ADDR %s\n", inet_ntoa(ciaddr1)));
				orc = CONFREJ;
				wo->req_addr = 0;	/* don't NAK with 0.0.0.0 later */
				break;
			}

			ho->neg_addr = 1;
			ho->hisaddr = ciaddr1;
			IPCPDEBUG(LOG_INFO, ("ipcp_reqci: ADDR %s\n", inet_ntoa(ciaddr1)));
			break;

		case CI_MS_DNS1:
		case CI_MS_DNS2:
			/* Microsoft primary or secondary DNS request */
			d = citype == CI_MS_DNS2;

			/* If we do not have a DNS address then we cannot send it */
			if (ao->dnsaddr[d] == 0 || cilen != CILEN_ADDR) {	/* Check CI length */
				IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Rejecting DNS%d Request\n", d + 1));
				orc = CONFREJ;	/* Reject CI */
				break;
			}
			GETLONG(tl, p);
			if (htonl(tl) != ao->dnsaddr[d]) {
				IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Naking DNS%d Request %s\n", d + 1, inet_ntoa(tl)));
				DECPTR(sizeof(u32_t), p);
				tl = ntohl(ao->dnsaddr[d]);
				PUTLONG(tl, p);
				orc = CONFNAK;
			}
			IPCPDEBUG(LOG_INFO, ("ipcp_reqci: received DNS%d Request\n", d + 1));
			break;

		case CI_MS_WINS1:
		case CI_MS_WINS2:
			/* Microsoft primary or secondary WINS request */
			d = citype == CI_MS_WINS2;
			IPCPDEBUG(LOG_INFO, ("ipcp_reqci: received WINS%d Request\n", d + 1));

			/* If we do not have a DNS address then we cannot send it */
			if (ao->winsaddr[d] == 0 || cilen != CILEN_ADDR) {	/* Check CI length */
				orc = CONFREJ;	/* Reject CI */
				break;
			}
			GETLONG(tl, p);
			if (htonl(tl) != ao->winsaddr[d]) {
				DECPTR(sizeof(u32_t), p);
				tl = ntohl(ao->winsaddr[d]);
				PUTLONG(tl, p);
				orc = CONFNAK;
			}
			break;

		case CI_COMPRESSTYPE:
			if (!ao->neg_vj) {
				IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Rejecting COMPRESSTYPE not allowed\n"));
				orc = CONFREJ;
				break;
			} else if (cilen != CILEN_VJ && cilen != CILEN_COMPRESS) {
				IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Rejecting COMPRESSTYPE len=%d\n", cilen));
				orc = CONFREJ;
				break;
			}
			GETSHORT(cishort, p);

			if (!(cishort == IPCP_VJ_COMP || (cishort == IPCP_VJ_COMP_OLD && cilen == CILEN_COMPRESS))) {
				IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Rejecting COMPRESSTYPE %d\n", cishort));
				orc = CONFREJ;
				break;
			}

			ho->neg_vj = 1;
			ho->vj_protocol = cishort;
			if (cilen == CILEN_VJ) {
				GETCHAR(maxslotindex, p);
				if (maxslotindex > ao->maxslotindex) {
					IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Naking VJ max slot %d\n", maxslotindex));
					orc = CONFNAK;
					if (!reject_if_disagree) {
						DECPTR(1, p);
						PUTCHAR(ao->maxslotindex, p);
					}
				}
				GETCHAR(cflag, p);
				if (cflag && !ao->cflag) {
					IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Naking VJ cflag %d\n", cflag));
					orc = CONFNAK;
					if (!reject_if_disagree) {
						DECPTR(1, p);
						PUTCHAR(wo->cflag, p);
					}
				}
				ho->maxslotindex = maxslotindex;
				ho->cflag = cflag;
			} else {
				ho->old_vj = 1;
				ho->maxslotindex = MAX_SLOTS - 1;
				ho->cflag = 1;
			}
			IPCPDEBUG(LOG_INFO, ("ipcp_reqci: received COMPRESSTYPE p=%d old=%d maxslot=%d cflag=%d\n", ho->vj_protocol, ho->old_vj, ho->maxslotindex, ho->cflag));
			break;

		default:
			IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Rejecting unknown CI type %d\n", citype));
			orc = CONFREJ;
			break;
		}

endswitch:
		if (orc == CONFACK &&	/* Good CI */
			rc != CONFACK) {	/*  but prior CI wasnt? */
			continue;			/* Don't send this one */
		}

		if (orc == CONFNAK) {	/* Nak this CI? */
			if (reject_if_disagree) {	/* Getting fed up with sending NAKs? */
				IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Rejecting too many naks\n"));
				orc = CONFREJ;	/* Get tough if so */
			} else {
				if (rc == CONFREJ) {	/* Rejecting prior CI? */
					continue;	/* Don't send this one */
				}
				if (rc == CONFACK) {	/* Ack'd all prior CIs? */
					rc = CONFNAK;	/* Not anymore... */
					ucp = inp;	/* Backup */
				}
			}
		}

		if (orc == CONFREJ &&	/* Reject this CI */
			rc != CONFREJ) {	/*  but no prior ones? */
			rc = CONFREJ;
			ucp = inp;			/* Backup */
		}

		/* Need to move CI? */
		if (ucp != cip) {
			BCOPY(cip, ucp, cilen);	/* Move it */
		}

		/* Update output pointer */
		INCPTR(cilen, ucp);
	}

	/*
	 * If we aren't rejecting this packet, and we want to negotiate
	 * their address, and they didn't send their address, then we
	 * send a NAK with a CI_ADDR option appended.  We assume the
	 * input buffer is long enough that we can append the extra
	 * option safely.
	 */
	if (rc != CONFREJ && !ho->neg_addr && wo->req_addr && !reject_if_disagree) {
		IPCPDEBUG(LOG_INFO, ("ipcp_reqci: Requesting peer address\n"));
		if (rc == CONFACK) {
			rc = CONFNAK;
			ucp = inp;			/* reset pointer */
			wo->req_addr = 0;	/* don't ask again */
		}
		PUTCHAR(CI_ADDR, ucp);
		PUTCHAR(CILEN_ADDR, ucp);
		tl = ntohl(wo->hisaddr);
		PUTLONG(tl, ucp);
	}

	*len = (int)(ucp - inp);	/* Compute output length */
	IPCPDEBUG(LOG_INFO, ("ipcp_reqci: returning Configure-%s\n", CODENAME(rc)));
	return (rc);				/* Return final code */
}

#if 0
/*
 * ip_check_options - check that any IP-related options are OK,
 * and assign appropriate defaults.
 */
static void ip_check_options(u_long localAddr)
{
	ipcp_options *wo = &ipcp_wantoptions[0];

	/*
	 * Load our default IP address but allow the remote host to give us
	 * a new address.
	 */
	if (wo->ouraddr == 0 && !ppp_settings.disable_defaultip) {
		wo->accept_local = 1;	/* don't insist on this default value */
		wo->ouraddr = htonl(localAddr);
	}
}
#endif

/*
 * ipcp_up - IPCP has come UP.
 *
 * Configure the IP network interface appropriately and bring it up.
 */
static void ipcp_up(fsm *f)
{
	u32_t mask;
	ipcp_options *ho = &ipcp_hisoptions[f->unit];
	ipcp_options *go = &ipcp_gotoptions[f->unit];
	ipcp_options *wo = &ipcp_wantoptions[f->unit];

	np_up(f->unit, PPP_IP);
	IPCPDEBUG(LOG_INFO, ("ipcp: up\n"));

	/*
	 * We must have a non-zero IP address for both ends of the link.
	 */
	if (!ho->neg_addr) {
		ho->hisaddr = wo->hisaddr;
	}

	if (ho->hisaddr == 0) {
		IPCPDEBUG(LOG_ERR, ("Could not determine remote IP address\n"));
		ipcp_close(f->unit, "Could not determine remote IP address");
		return;
	}
	if (go->ouraddr == 0) {
		IPCPDEBUG(LOG_ERR, ("Could not determine local IP address\n"));
		ipcp_close(f->unit, "Could not determine local IP address");
		return;
	}

	if (ppp_settings.usepeerdns && (go->dnsaddr[0] || go->dnsaddr[1])) {
		/*pppGotDNSAddrs(go->dnsaddr[0], go->dnsaddr[1]); */
	}

	/*
	 * Check that the peer is allowed to use the IP address it wants.
	 */
	if (!auth_ip_addr(f->unit, ho->hisaddr)) {
		IPCPDEBUG(LOG_ERR, ("Peer is not authorized to use remote address %s\n", inet_ntoa(ho->hisaddr)));
		ipcp_close(f->unit, "Unauthorized remote IP address");
		return;
	}

	/* set tcp compression */
	sifvjcomp(f->unit, ho->neg_vj, ho->cflag, ho->maxslotindex);

	/*
	 * Set IP addresses and (if specified) netmask.
	 */
	mask = GetMask(go->ouraddr);

	if (!sifaddr(f->unit, go->ouraddr, ho->hisaddr, mask, go->dnsaddr[0], go->dnsaddr[1])) {
		IPCPDEBUG(LOG_WARNING, ("sifaddr failed\n"));
		ipcp_close(f->unit, "Interface configuration failed");
		return;
	}

	/* bring the interface up for IP */
	if (!sifup(f->unit)) {
		IPCPDEBUG(LOG_WARNING, ("sifup failed\n"));
		ipcp_close(f->unit, "Interface configuration failed");
		return;
	}

	sifnpmode(f->unit, PPP_IP, NPMODE_PASS);

	/* assign a default route through the interface if required */
	if (ipcp_wantoptions[f->unit].default_route) {
		if (sifdefaultroute(f->unit, go->ouraddr, ho->hisaddr)) {
			default_route_set[f->unit] = 1;
		}
	}

	IPCPDEBUG(LOG_NOTICE, ("local  IP address %s\n", inet_ntoa(go->ouraddr)));
	IPCPDEBUG(LOG_NOTICE, ("remote IP address %s\n", inet_ntoa(ho->hisaddr)));
	if (go->dnsaddr[0]) {
		IPCPDEBUG(LOG_NOTICE, ("primary   DNS address %s\n", inet_ntoa(go->dnsaddr[0])));
	}
	if (go->dnsaddr[1]) {
		IPCPDEBUG(LOG_NOTICE, ("secondary DNS address %s\n", inet_ntoa(go->dnsaddr[1])));
	}
}

/*
 * ipcp_down - IPCP has gone DOWN.
 *
 * Take the IP network interface down, clear its addresses
 * and delete routes through it.
 */
static void ipcp_down(fsm *f)
{
	IPCPDEBUG(LOG_INFO, ("ipcp: down\n"));
	np_down(f->unit, PPP_IP);
	sifvjcomp(f->unit, 0, 0, 0);

	sifdown(f->unit);
	ipcp_clear_addrs(f->unit);
}

/*
 * ipcp_clear_addrs() - clear the interface addresses, routes, etc.
 */
static void ipcp_clear_addrs(int unit)
{
	u32_t ouraddr, hisaddr;

	ouraddr = ipcp_gotoptions[unit].ouraddr;
	hisaddr = ipcp_hisoptions[unit].hisaddr;
	if (default_route_set[unit]) {
		cifdefaultroute(unit, ouraddr, hisaddr);
		default_route_set[unit] = 0;
	}
	cifaddr(unit, ouraddr, hisaddr);
}

/*
 * ipcp_finished - possibly shut down the lower layers.
 */
static void ipcp_finished(fsm *f)
{
	np_finished(f->unit, PPP_IP);
}

#if PPP_ADDITIONAL_CALLBACKS
static int ipcp_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;
}

/*
 * ip_active_pkt - see if this IP packet is worth bringing the link up for.
 * We don't bring the link up for IP fragments or for TCP FIN packets
 * with no data.
 */
#define IP_HDRLEN   20			/* bytes */
#define IP_OFFMASK  0x1fff
#define IPPROTO_TCP 6
#define TCP_HDRLEN  20
#define TH_FIN      0x01

/*
 * We use these macros because the IP header may be at an odd address,
 * and some compilers might use word loads to get th_off or ip_hl.
 */

#define net_short(x)    (((x)[0] << 8) + (x)[1])
#define get_iphl(x)     (((unsigned char *)(x))[0] & 0xF)
#define get_ipoff(x)    net_short((unsigned char *)(x) + 6)
#define get_ipproto(x)  (((unsigned char *)(x))[9])
#define get_tcpoff(x)   (((unsigned char *)(x))[12] >> 4)
#define get_tcpflags(x) (((unsigned char *)(x))[13])

static int ip_active_pkt(u_char *pkt, int len)
{
	u_char *tcp;
	int hlen;

	len -= PPP_HDRLEN;
	pkt += PPP_HDRLEN;
	if (len < IP_HDRLEN) {
		return 0;
	}
	if ((get_ipoff(pkt) & IP_OFFMASK) != 0) {
		return 0;
	}
	if (get_ipproto(pkt) != IPPROTO_TCP) {
		return 1;
	}
	hlen = get_iphl(pkt) * 4;
	if (len < hlen + TCP_HDRLEN) {
		return 0;
	}
	tcp = pkt + hlen;
	if ((get_tcpflags(tcp) & TH_FIN) != 0 && len == hlen + get_tcpoff(tcp) * 4) {
		return 0;
	}
	return 1;
}
#endif							/* PPP_ADDITIONAL_CALLBACKS */

#endif							/* PPP_SUPPORT */
