upap.c

自己精简过的PPPD代码。在嵌入中应用可以更好的发挥。比原先的小了很多

/*
 * upap.c - User/Password Authentication Protocol.
 *
 * Copyright (c) 1984-2000 Carnegie Mellon University. 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 "Carnegie Mellon University" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For permission or any legal
 *    details, please contact
 *      Office of Technology Transfer
 *      Carnegie Mellon University
 *      5000 Forbes Avenue
 *      Pittsburgh, PA  15213-3890
 *      [phone], fax: [phone]
 *      [e-mail]
 *
 * 4. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by Computing Services
 *     at Carnegie Mellon University (http://www.cmu.edu/computing/)."
 *
 * CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
 * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#define RCSID	"$Id: upap.c,v 1.30 2005/07/13 10:41:58 paulus Exp $"

/*
 * TODO:
 */

#include <stdio.h>
#include <string.h>

#include "pppd.h"
#include "upap.h"

static const char rcsid[] = RCSID;

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", OPT_PRIO | 1 },
    { "show-password", o_bool, &hide_password,
      "Show password string in debug log messages", OPT_PRIOSUB | 0 },

    { "pap-restart", o_int, &upap[0].us_timeouttime,
      "Set retransmit timeout for PAP", OPT_PRIO },
    { "pap-max-authreq", o_int, &upap[0].us_maxtransmits,
      "Set max number of transmissions for auth-reqs", OPT_PRIO },
    { "pap-timeout", o_int, &upap[0].us_reqtimeout,
      "Set time limit for peer PAP authentication", OPT_PRIO },

    { NULL }
};

/*
 * Protocol entry points.
 */
static void upap_init __P((int));
static void upap_lowerup __P((int));
static void upap_lowerdown __P((int));
static void upap_input __P((int, u_char *, int));
static void upap_protrej __P((int));
static int  upap_printpkt __P((u_char *, int,
			       void (*) __P((void *, char *, ...)), void *));

struct protent pap_protent = {
    PPP_PAP,
    upap_init,
    upap_input,
    upap_protrej,
    upap_lowerup,
    upap_lowerdown,
    NULL,
    NULL,
    upap_printpkt,
    NULL,
    1,
    "PAP",
    NULL,
    pap_option_list,
    NULL,
    NULL,
    NULL
};

upap_state upap[NUM_PPP];		/* UPAP state; one for each unit */

static void upap_timeout __P((void *));
static void upap_reqtimeout __P((void *));
static void upap_rauthreq __P((upap_state *, u_char *, int, int));
static void upap_rauthack __P((upap_state *, u_char *, int, int));
static void upap_rauthnak __P((upap_state *, u_char *, int, int));
static void upap_sauthreq __P((upap_state *));
static void upap_sresp __P((upap_state *, int, int, char *, int));


/*
 * upap_init - Initialize a UPAP unit.
 */
static void
upap_init(unit)
    int unit;
{
    upap_state *u = &upap[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(unit, user, password)
    int unit;
    char *user, *password;
{
    upap_state *u = &upap[unit];

    /* Save the username and password we're given */
    u->us_user = user;
    u->us_userlen = strlen(user);
    u->us_passwd = password;
    u->us_passwdlen = 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(unit)
    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(arg)
    void *arg;
{
    upap_state *u = (upap_state *) arg;

    if (u->us_clientstate != UPAPCS_AUTHREQ)
	return;

    if (u->us_transmits >= u->us_maxtransmits) {
	/* give up in disgust */
	error("No response to PAP authenticate-requests");
	u->us_clientstate = UPAPCS_BADAUTH;
	auth_withpeer_fail(u->us_unit, PPP_PAP);
	return;
    }

    upap_sauthreq(u);		/* Send Authenticate-Request */
}


/*
 * upap_reqtimeout - Give up waiting for the peer to send an auth-req.
 */
static void
upap_reqtimeout(arg)
    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(unit)
    int unit;
{
    upap_state *u = &upap[unit];

    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 */
    }

    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(unit)
    int unit;
{
    upap_state *u = &upap[unit];

    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(unit)
    int unit;
{
    upap_state *u = &upap[unit];

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


/*
 * upap_input - Input UPAP packet.
 */
static void
upap_input(unit, inpacket, l)
    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 < UPAP_HEADERLEN) {
	UPAPDEBUG(("pap_input: rcvd short header."));
	return;
    }
    GETCHAR(code, inp);
    GETCHAR(id, inp);
    GETSHORT(len, inp);
    if (len < UPAP_HEADERLEN) {
	UPAPDEBUG(("pap_input: rcvd illegal length."));
	return;
    }
    if (len > l) {
	UPAPDEBUG(("pap_input: rcvd short packet."));
	return;
    }