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

    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 */
	break;
    }
}


/*
 * upap_rauth - Receive Authenticate.
 */
static void
upap_rauthreq(u, inp, id, len)
    upap_state *u;
    u_char *inp;
    int id;
    int len;
{
    u_char ruserlen, rpasswdlen;
    char *ruser, *rpasswd;
    char rhostname[256];
    int retcode;
    char *msg;
    int msglen;

    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 < 1) {
	UPAPDEBUG(("pap_rauth: rcvd short packet."));
	return;
    }
    GETCHAR(ruserlen, inp);
    len -= sizeof (u_char) + ruserlen + sizeof (u_char);
    if (len < 0) {
	UPAPDEBUG(("pap_rauth: rcvd short packet."));
	return;
    }
    ruser = (char *) inp;
    INCPTR(ruserlen, inp);
    GETCHAR(rpasswdlen, inp);
    if (len < rpasswdlen) {
	UPAPDEBUG(("pap_rauth: rcvd short packet."));
	return;
    }
    rpasswd = (char *) inp;

    /*
     * Check the username and password given.
     */
    /*/retcode = check_passwd(u->us_unit, ruser, ruserlen, rpasswd,
			   rpasswdlen, &msg);*/
    BZERO(rpasswd, rpasswdlen);

    /*
     * Check remote number authorization.  A plugin may have filled in
     * the remote number or added an allowed number, and rather than
     * return an authenticate failure, is leaving it for us to verify.
     */
    if (retcode == UPAP_AUTHACK) {
	if (!auth_number()) {
	    /* We do not want to leak info about the pap result. */
	    retcode = UPAP_AUTHNAK; /* XXX exit value will be "wrong" */
	    warn("calling number %q is not authorized", remote_number);
	}
    }

    msglen = strlen(msg);
    if (msglen > 255)
	msglen = 255;
    upap_sresp(u, retcode, id, msg, msglen);

    /* Null terminate and clean remote name. */
    slprintf(rhostname, sizeof(rhostname), "%.*v", ruserlen, ruser);

    if (retcode == UPAP_AUTHACK) {
	u->us_serverstate = UPAPSS_OPEN;
	notice("PAP peer authentication succeeded for %q", rhostname);
	auth_peer_success(u->us_unit, PPP_PAP, 0, ruser, ruserlen);
    } else {
	u->us_serverstate = UPAPSS_BADAUTH;
	warn("PAP peer authentication failed for %q", rhostname);
	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(u, inp, id, len)
    upap_state *u;
    u_char *inp;
    int id;
    int len;
{
    u_char msglen;
    char *msg;

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

    /*
     * Parse message.
     */
    if (len < 1) {
	UPAPDEBUG(("pap_rauthack: ignoring missing msg-length."));
    } else {
	GETCHAR(msglen, inp);
	if (msglen > 0) {
	    len -= sizeof (u_char);
	    if (len < msglen) {
		UPAPDEBUG(("pap_rauthack: rcvd short packet."));
		return;
	    }
	    msg = (char *) inp;
	    PRINTMSG(msg, msglen);
	}
    }

    u->us_clientstate = UPAPCS_OPEN;

    auth_withpeer_success(u->us_unit, PPP_PAP, 0);
}


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

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

    /*
     * Parse message.
     */
    if (len < 1) {
	UPAPDEBUG(("pap_rauthnak: ignoring missing msg-length."));
    } else {
	GETCHAR(msglen, inp);
	if (msglen > 0) {
	    len -= sizeof (u_char);
	    if (len < msglen) {
		UPAPDEBUG(("pap_rauthnak: rcvd short packet."));
		return;
	    }
	    msg = (char *) inp;
	    PRINTMSG(msg, msglen);
	}
    }

    u->us_clientstate = UPAPCS_BADAUTH;

    error("PAP authentication failed");
    auth_withpeer_fail(u->us_unit, PPP_PAP);
}


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

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

    output(u->us_unit, outpacket_buf, outlen + PPP_HDRLEN);

    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(u, code, id, msg, msglen)
    upap_state *u;
    u_char code, id;
    char *msg;
    int msglen;
{
    u_char *outp;
    int outlen;

    outlen = UPAP_HEADERLEN + sizeof (u_char) + msglen;
    outp = outpacket_buf;
    MAKEHEADER(outp, PPP_PAP);

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

/*
 * upap_printpkt - print the contents of a PAP packet.
 */
static char *upap_codenames[] = {
    "AuthReq", "AuthAck", "AuthNak"
};

static int
upap_printpkt(p, plen, printer, arg)
    u_char *p;
    int plen;
    void (*printer) __P((void *, char *, ...));
    void *arg;
{
    int code, id, len;
    int mlen, ulen, wlen;
    char *user, *pwd, *msg;
    u_char *pstart;

    if (plen < UPAP_HEADERLEN)
	return 0;
    pstart = p;
    GETCHAR(code, p);
    GETCHAR(id, p);
    GETSHORT(len, p);
    if (len < UPAP_HEADERLEN || len > plen)
	return 0;

    if (code >= 1 && code <= sizeof(upap_codenames) / sizeof(char *))
	printer(arg, " %s", upap_codenames[code-1]);
    else
	printer(arg, " code=0x%x", code);
    printer(arg, " id=0x%x", id);
    len -= UPAP_HEADERLEN;
    switch (code) {
    case UPAP_AUTHREQ:
	if (len < 1)
	    break;
	ulen = p[0];
	if (len < ulen + 2)
	    break;
	wlen = p[ulen + 1];
	if (len < ulen + wlen + 2)
	    break;
	user = (char *) (p + 1);
	pwd = (char *) (p + ulen + 2);
	p += ulen + wlen + 2;
	len -= ulen + wlen + 2;
	printer(arg, " user=");
	print_string(user, ulen, printer, arg);
	printer(arg, " password=");
	if (!hide_password)
	    print_string(pwd, wlen, printer, arg);
	else
	    printer(arg, "<hidden>");
	break;
    case UPAP_AUTHACK:
    case UPAP_AUTHNAK:
	if (len < 1)
	    break;
	mlen = p[0];
	if (len < mlen + 1)
	    break;
	msg = (char *) (p + 1);
	p += mlen + 1;
	len -= mlen + 1;
	printer(arg, " ");
	print_string(msg, mlen, printer, arg);
	break;
    }

    /* print the rest of the bytes in the packet */
    for (; len > 0; --len) {
	GETCHAR(code, p);
	printer(arg, " %.2x", code);
    }

    return p - pstart;
}