ipcp.c

RTEMS (Real-Time Executive for Multiprocessor Systems) is a free open source real-time operating sys

/*
 * 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.
 */

#define RCSID	"$Id: ipcp.c,v 1.4 2002/09/07 23:07:58 joel Exp $"

/*
 * TODO:
 */

#include <stdio.h>
#include <string.h>
#include <netdb.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <resolv.h>

#include "pppd.h"
#include "fsm.h"
#include "ipcp.h"
#include "pathnames.h"

static const char rcsid[] = RCSID;

/* 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 */

bool	disable_defaultip = 0;	/* Don't use hostname for default IP adrs */

/* Hook for a plugin to know when IP protocol has come up */
void (*ip_up_hook) __P((void)) = NULL;

/* Hook for a plugin to know when IP protocol has come down */
void (*ip_down_hook) __P((void)) = NULL;

/* local vars */
static int default_route_set[NUM_PPP];	/* Have set up a default route */
static int proxy_arp_set[NUM_PPP];	/* Have created proxy arp entry */
static bool usepeerdns;			/* Ask peer for DNS addrs */
static int ipcp_is_up;			/* have called np_up() */

/*
 * Callbacks for fsm code.  (CI = Configuration Information)
 */
static void ipcp_resetci __P((fsm *));	/* Reset our CI */
static int  ipcp_cilen __P((fsm *));	        /* Return length of our CI */
static void ipcp_addci __P((fsm *, u_char *, int *)); /* Add our CI */
static int  ipcp_ackci __P((fsm *, u_char *, int));	/* Peer ack'd our CI */
static int  ipcp_nakci __P((fsm *, u_char *, int));	/* Peer nak'd our CI */
static int  ipcp_rejci __P((fsm *, u_char *, int));	/* Peer rej'd our CI */
static int  ipcp_reqci __P((fsm *, u_char *, int *, int)); /* Rcv CI */
static void ipcp_up __P((fsm *));		/* We're UP */
static void ipcp_down __P((fsm *));		/* We're DOWN */
static void ipcp_finished __P((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 OPENED state */
    ipcp_down,			/* Called when fsm leaves 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 */
};

/*
 * Command-line options.
 */
static int setvjslots __P((char **));
static int setdnsaddr __P((char **));
static int setwinsaddr __P((char **));

static option_t ipcp_option_list[] = {
    { "noip", o_bool, &ipcp_protent.enabled_flag,
      "Disable IP and IPCP" },
    { "-ip", o_bool, &ipcp_protent.enabled_flag,
      "Disable IP and IPCP" },
    { "novj", o_bool, &ipcp_wantoptions[0].neg_vj,
      "Disable VJ compression", OPT_A2COPY, &ipcp_allowoptions[0].neg_vj },
    { "-vj", o_bool, &ipcp_wantoptions[0].neg_vj,
      "Disable VJ compression", OPT_A2COPY, &ipcp_allowoptions[0].neg_vj },
    { "novjccomp", o_bool, &ipcp_wantoptions[0].cflag,
      "Disable VJ connection-ID compression", OPT_A2COPY,
      &ipcp_allowoptions[0].cflag },
    { "-vjccomp", o_bool, &ipcp_wantoptions[0].cflag,
      "Disable VJ connection-ID compression", OPT_A2COPY,
      &ipcp_allowoptions[0].cflag },
    { "vj-max-slots", 1, setvjslots,
      "Set maximum VJ header slots" },
    { "ipcp-accept-local", o_bool, &ipcp_wantoptions[0].accept_local,
      "Accept peer's address for us", 1 },
    { "ipcp-accept-remote", o_bool, &ipcp_wantoptions[0].accept_remote,
      "Accept peer's address for it", 1 },
    { "ipparam", o_string, &ipparam,
      "Set ip script parameter" },
    { "noipdefault", o_bool, &disable_defaultip,
      "Don't use name for default IP adrs", 1 },
    { "ms-dns", 1, setdnsaddr,
      "DNS address for the peer's use" },
    { "ms-wins", 1, setwinsaddr,
      "Nameserver for SMB over TCP/IP for peer" },
    { "ipcp-restart", o_int, &ipcp_fsm[0].timeouttime,
      "Set timeout for IPCP" },
    { "ipcp-max-terminate", o_int, &ipcp_fsm[0].maxtermtransmits,
      "Set max #xmits for term-reqs" },
    { "ipcp-max-configure", o_int, &ipcp_fsm[0].maxconfreqtransmits,
      "Set max #xmits for conf-reqs" },
    { "ipcp-max-failure", o_int, &ipcp_fsm[0].maxnakloops,
      "Set max #conf-naks for IPCP" },
    { "defaultroute", o_bool, &ipcp_wantoptions[0].default_route,
      "Add default route", OPT_ENABLE|1, &ipcp_allowoptions[0].default_route },
    { "nodefaultroute", o_bool, &ipcp_allowoptions[0].default_route,
      "disable defaultroute option", OPT_A2COPY,
      &ipcp_wantoptions[0].default_route },
    { "-defaultroute", o_bool, &ipcp_allowoptions[0].default_route,
      "disable defaultroute option", OPT_A2COPY,
      &ipcp_wantoptions[0].default_route },
    { "proxyarp", o_bool, &ipcp_wantoptions[0].proxy_arp,
      "Add proxy ARP entry", OPT_ENABLE|1, &ipcp_allowoptions[0].proxy_arp },
    { "noproxyarp", o_bool, &ipcp_allowoptions[0].proxy_arp,
      "disable proxyarp option", OPT_A2COPY,
      &ipcp_wantoptions[0].proxy_arp },
    { "-proxyarp", o_bool, &ipcp_allowoptions[0].proxy_arp,
      "disable proxyarp option", OPT_A2COPY,
      &ipcp_wantoptions[0].proxy_arp },
    { "usepeerdns", o_bool, &usepeerdns,
      "Ask peer for DNS address(es)", 1 },
    { NULL }
};

/*
 * Protocol entry points from main code.
 */
static void ipcp_init __P((int));
static void ipcp_open __P((int));
static void ipcp_close __P((int, char *));
static void ipcp_lowerup __P((int));
static void ipcp_lowerdown __P((int));
static void ipcp_input __P((int, u_char *, int));
static void ipcp_protrej __P((int));
static int  ipcp_printpkt __P((u_char *, int,
			       void (*) __P((void *, char *, ...)), void *));
static void ip_check_options __P((void));
static int  ip_demand_conf __P((int));
static int  ip_active_pkt __P((u_char *, int));
static void create_resolv __P((u_int32_t, u_int32_t));

struct protent ipcp_protent = {
    PPP_IPCP,
    ipcp_init,
    ipcp_input,
    ipcp_protrej,
    ipcp_lowerup,
    ipcp_lowerdown,
    ipcp_open,
    ipcp_close,
    ipcp_printpkt,
    NULL,
    1,
    "IPCP",
    "IP",
    ipcp_option_list,
    ip_check_options,
    ip_demand_conf,
    ip_active_pkt
};

static void ipcp_clear_addrs __P((int, u_int32_t, u_int32_t));

/*
 * 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")

/*
 * Make a string representation of a network IP address.
 */
char *
ip_ntoa(ipaddr)
u_int32_t ipaddr;
{
    static char b[64];

    slprintf(b, sizeof(b), "%I", ipaddr);
    return b;
}

/*
 * Option parsing.
 */

/*
 * setvjslots - set maximum number of connection slots for VJ compression
 */
static int
setvjslots(argv)
    char **argv;
{
    int value;

    if (!int_option(*argv, &value))
	return 0;
    if (value < 2 || value > 16) {
	option_error("vj-max-slots value must be between 2 and 16");
	return 0;
    }
    ipcp_wantoptions [0].maxslotindex =
        ipcp_allowoptions[0].maxslotindex = value - 1;
    return 1;
}

/*
 * setdnsaddr - set the dns address(es)
 */
static int
setdnsaddr(argv)
    char **argv;
{
    u_int32_t dns;
    struct hostent *hp;

    dns = inet_addr(*argv);
    if (dns == (u_int32_t) -1) {
	if ((hp = gethostbyname(*argv)) == NULL) {
	    option_error("invalid address parameter '%s' for ms-dns option",
			 *argv);
	    return 0;
	}
	dns = *(u_int32_t *)hp->h_addr;
    }

    /* if there is no primary then update it. */
    if (ipcp_allowoptions[0].dnsaddr[0] == 0)
	ipcp_allowoptions[0].dnsaddr[0] = dns;

    /* always set the secondary address value to the same value. */
    ipcp_allowoptions[0].dnsaddr[1] = dns;

    return (1);
}

/*
 * setwinsaddr - set the wins address(es)
 * This is primrarly used with the Samba package under UNIX or for pointing
 * the caller to the existing WINS server on a Windows NT platform.
 */
static int
setwinsaddr(argv)
    char **argv;
{
    u_int32_t wins;
    struct hostent *hp;

    wins = inet_addr(*argv);
    if (wins == (u_int32_t) -1) {
	if ((hp = gethostbyname(*argv)) == NULL) {
	    option_error("invalid address parameter '%s' for ms-wins option",
			 *argv);
	    return 0;
	}
	wins = *(u_int32_t *)hp->h_addr;
    }

    /* if there is no primary then update it. */
    if (ipcp_allowoptions[0].winsaddr[0] == 0)
	ipcp_allowoptions[0].winsaddr[0] = wins;

    /* always set the secondary address value to the same value. */
    ipcp_allowoptions[0].winsaddr[1] = wins;

    return (1);
}


/*
 * ipcp_init - Initialize IPCP.
 */
static void
ipcp_init(unit)
    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->neg_vj = 1;
    wo->vj_protocol = IPCP_VJ_COMP;
    wo->maxslotindex = MAX_STATES - 1; /* really max index */
    wo->cflag = 1;

    /* max slots and slot-id compression are currently hardwired in */
    /* ppp_if.c to 16 and 1, this needs to be changed (among other */
    /* things) gmc */

    ao->neg_addr = 1;
    ao->neg_vj = 1;
    ao->maxslotindex = MAX_STATES - 1;
    ao->cflag = 1;

    /*
     * XXX These control whether the user may use the proxyarp
     * and defaultroute options.
     */
    ao->proxy_arp = 1;
    ao->default_route = 1;
}


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


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


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


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


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


/*
 * ipcp_resetci - Reset our CI.
 * Called by fsm_sconfreq, Send Configure Request.
 */
static void
ipcp_resetci(f)
    fsm *f;
{
    ipcp_options *wo = &ipcp_wantoptions[f->unit];
    ipcp_options *go = &ipcp_gotoptions[f->unit];

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


/*
 * ipcp_cilen - Return length of our CI.
 * Called by fsm_sconfreq, Send Configure Request.
 */
static int
ipcp_cilen(f)
    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 */
	/* 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.
 * Called by fsm_sconfreq, Send Configure Request.
 */
static void
ipcp_addci(f, ucp, lenp)
    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) { \
	    u_int32_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) { \
	    u_int32_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.
 * Called by fsm_rconfack, Receive Configure ACK.
 *
 * Returns:
 *	0 - Ack was bad.
 *	1 - Ack was good.
 */
static int
ipcp_ackci(f, p, len)
    fsm *f;
    u_char *p;
    int len;
{
    ipcp_options *go = &ipcp_gotoptions[f->unit];
    u_short cilen, citype, cishort;
    u_int32_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.