sys-linux.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

	set_kdebugflag (kdebugflag);

    looped = 0;

    return ppp_fd;

 err_close:
    close(fd);
 err:
    return -1;
}

/********************************************************************
 *
 * tty_disestablish_ppp - Restore the serial port to normal operation.
 * This shouldn't call die() because it's called from die().
 */

void tty_disestablish_ppp(int tty_fd)
{
    if (!hungup) {
/*
 * Flush the tty output buffer so that the TIOCSETD doesn't hang.
 */
	if (tcflush(tty_fd, TCIOFLUSH) < 0)
	{
	    warn("tcflush failed: %m");
	    goto flushfailed;
	}
/*
 * Restore the previous line discipline
 */
	if (ioctl(tty_fd, TIOCSETD, &tty_disc) < 0) {
	    if ( ! ok_error (errno))
		error("ioctl(TIOCSETD, N_TTY): %m (line %d)", __LINE__);
	}

	if (ioctl(tty_fd, TIOCNXCL, 0) < 0) {
	    if ( ! ok_error (errno))
		warn("ioctl(TIOCNXCL): %m (line %d)", __LINE__);
	}

	/* Reset non-blocking mode on fd. */
	if (initfdflags != -1 && fcntl(tty_fd, F_SETFL, initfdflags) < 0) {
	    if ( ! ok_error (errno))
		warn("Couldn't restore device fd flags: %m");
	}
    }
flushfailed:
    initfdflags = -1;

    generic_disestablish_ppp(tty_fd);
}

/********************************************************************
 *
 * generic_disestablish_ppp - Restore device components to normal
 * operation, and reconnect the ppp unit to the loopback if in demand
 * mode.  This shouldn't call die() because it's called from die().
 */
void generic_disestablish_ppp(int dev_fd)
{
    if (new_style_driver) {
	close(ppp_fd);
	ppp_fd = -1;
	if (demand) {
	    modify_flags(ppp_dev_fd, 0, SC_LOOP_TRAFFIC);
	    looped = 1;
	} else if (!doing_multilink && ppp_dev_fd >= 0) {
	    close(ppp_dev_fd);
	    remove_fd(ppp_dev_fd);
	    ppp_dev_fd = -1;
	}
    } else {
	/* old-style driver */
	if (demand)
	    set_ppp_fd(slave_fd);
	else
	    ppp_dev_fd = -1;
    }
}

/*
 * make_ppp_unit - make a new ppp unit for ppp_dev_fd.
 * Assumes new_style_driver.
 */
static int make_ppp_unit()
{
	int x, flags;

	if (ppp_dev_fd >= 0) {
		dbglog("in make_ppp_unit, already had /dev/ppp open?");
		close(ppp_dev_fd);
	}
	ppp_dev_fd = open("/dev/ppp", O_RDWR);
	if (ppp_dev_fd < 0)
		fatal("Couldn't open /dev/ppp: %m");
	flags = fcntl(ppp_dev_fd, F_GETFL);
	if (flags == -1
	    || fcntl(ppp_dev_fd, F_SETFL, flags | O_NONBLOCK) == -1)
		warn("Couldn't set /dev/ppp to nonblock: %m");

	ifunit = req_unit;
	x = ioctl(ppp_dev_fd, PPPIOCNEWUNIT, &ifunit);
	if (x < 0 && req_unit >= 0 && errno == EEXIST) {
		warn("Couldn't allocate PPP unit %d as it is already in use", req_unit);
		ifunit = -1;
		x = ioctl(ppp_dev_fd, PPPIOCNEWUNIT, &ifunit);
	}
	if (x < 0)
		error("Couldn't create new ppp unit: %m");
	return x;
}

/*
 * cfg_bundle - configure the existing bundle.
 * Used in demand mode.
 */
void cfg_bundle(int mrru, int mtru, int rssn, int tssn)
{
	if (!new_style_driver)
		return;

	/* set the mrru, mtu and flags */
	if (ioctl(ppp_dev_fd, PPPIOCSMRRU, &mrru) < 0)
		error("Couldn't set MRRU: %m");

	modify_flags(ppp_dev_fd, SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ|SC_MULTILINK,
		     ((rssn? SC_MP_SHORTSEQ: 0) | (tssn? SC_MP_XSHORTSEQ: 0)
		      | (mrru? SC_MULTILINK: 0)));

	/* connect up the channel */
	if (ioctl(ppp_fd, PPPIOCCONNECT, &ifunit) < 0)
		fatal("Couldn't attach to PPP unit %d: %m", ifunit);
	add_fd(ppp_dev_fd);
}

/*
 * make_new_bundle - create a new PPP unit (i.e. a bundle)
 * and connect our channel to it.  This should only get called
 * if `multilink' was set at the time establish_ppp was called.
 * In demand mode this uses our existing bundle instead of making
 * a new one.
 */
void make_new_bundle(int mrru, int mtru, int rssn, int tssn)
{
	if (!new_style_driver)
		return;

	/* make us a ppp unit */
	if (make_ppp_unit() < 0)
		die(1);

	/* set the mrru and flags */
	cfg_bundle(mrru, mtru, rssn, tssn);
}

/*
 * bundle_attach - attach our link to a given PPP unit.
 * We assume the unit is controlled by another pppd.
 */
int bundle_attach(int ifnum)
{
	int master_fd;

	if (!new_style_driver)
		return -1;

	master_fd = open("/dev/ppp", O_RDWR);
	if (master_fd < 0)
		fatal("Couldn't open /dev/ppp: %m");
	if (ioctl(master_fd, PPPIOCATTACH, &ifnum) < 0) {
		if (errno == ENXIO) {
			close(master_fd);
			return 0;	/* doesn't still exist */
		}
		fatal("Couldn't attach to interface unit %d: %m\n", ifnum);
	}
	if (ioctl(ppp_fd, PPPIOCCONNECT, &ifnum) < 0)
		fatal("Couldn't connect to interface unit %d: %m", ifnum);
	modify_flags(master_fd, 0, SC_MULTILINK);
	close(master_fd);

	ifunit = ifnum;
	return 1;
}

/*
 * destroy_bundle - tell the driver to destroy our bundle.
 */
void destroy_bundle(void)
{
	if (ppp_dev_fd >= 0) {
		close(ppp_dev_fd);
		remove_fd(ppp_dev_fd);
		ppp_dev_fd = -1;
	}
}

/********************************************************************
 *
 * clean_check - Fetch the flags for the device and generate
 * appropriate error messages.
 */
void clean_check(void)
{
    int x;
    char *s;

    if (still_ppp()) {
	if (ioctl(ppp_fd, PPPIOCGFLAGS, (caddr_t) &x) == 0) {
	    s = NULL;
	    switch (~x & (SC_RCV_B7_0|SC_RCV_B7_1|SC_RCV_EVNP|SC_RCV_ODDP)) {
	    case SC_RCV_B7_0:
		s = "all had bit 7 set to 1";
		break;

	    case SC_RCV_B7_1:
		s = "all had bit 7 set to 0";
		break;

	    case SC_RCV_EVNP:
		s = "all had odd parity";
		break;

	    case SC_RCV_ODDP:
		s = "all had even parity";
		break;
	    }

	    if (s != NULL) {
		warn("Receive serial link is not 8-bit clean:");
		warn("Problem: %s", s);
	    }
	}
    }
}


/*
 * List of valid speeds.
 */

struct speed {
    int speed_int, speed_val;
} speeds[] = {
#ifdef B50
    { 50, B50 },
#endif
#ifdef B75
    { 75, B75 },
#endif
#ifdef B110
    { 110, B110 },
#endif
#ifdef B134
    { 134, B134 },
#endif
#ifdef B150
    { 150, B150 },
#endif
#ifdef B200
    { 200, B200 },
#endif
#ifdef B300
    { 300, B300 },
#endif
#ifdef B600
    { 600, B600 },
#endif
#ifdef B1200
    { 1200, B1200 },
#endif
#ifdef B1800
    { 1800, B1800 },
#endif
#ifdef B2000
    { 2000, B2000 },
#endif
#ifdef B2400
    { 2400, B2400 },
#endif
#ifdef B3600
    { 3600, B3600 },
#endif
#ifdef B4800
    { 4800, B4800 },
#endif
#ifdef B7200
    { 7200, B7200 },
#endif
#ifdef B9600
    { 9600, B9600 },
#endif
#ifdef B19200
    { 19200, B19200 },
#endif
#ifdef B38400
    { 38400, B38400 },
#endif
#ifdef B57600
    { 57600, B57600 },
#endif
#ifdef B76800
    { 76800, B76800 },
#endif
#ifdef B115200
    { 115200, B115200 },
#endif
#ifdef EXTA
    { 19200, EXTA },
#endif
#ifdef EXTB
    { 38400, EXTB },
#endif
#ifdef B230400
    { 230400, B230400 },
#endif
#ifdef B460800
    { 460800, B460800 },
#endif
#ifdef B921600
    { 921600, B921600 },
#endif
    { 0, 0 }
};

/********************************************************************
 *
 * Translate from bits/second to a speed_t.
 */

static int translate_speed (int bps)
{
    struct speed *speedp;

    if (bps != 0) {
	for (speedp = speeds; speedp->speed_int; speedp++) {
	    if (bps == speedp->speed_int)
		return speedp->speed_val;
	}
	warn("speed %d not supported", bps);
    }
    return 0;
}

/********************************************************************
 *
 * Translate from a speed_t to bits/second.
 */

static int baud_rate_of (int speed)
{
    struct speed *speedp;

    if (speed != 0) {
	for (speedp = speeds; speedp->speed_int; speedp++) {
	    if (speed == speedp->speed_val)
		return speedp->speed_int;
	}
    }
    return 0;
}

/********************************************************************
 *
 * set_up_tty: Set up the serial port on `fd' for 8 bits, no parity,
 * at the requested speed, etc.  If `local' is true, set CLOCAL
 * regardless of whether the modem option was specified.
 */

void set_up_tty(int tty_fd, int local)
{
    int speed;
    struct termios tios;

    setdtr(tty_fd, 1);
    if (tcgetattr(tty_fd, &tios) < 0) {
	if (!ok_error(errno))
	    fatal("tcgetattr: %m (line %d)", __LINE__);
	return;
    }

    if (!restore_term)
	inittermios = tios;

    tios.c_cflag     &= ~(CSIZE | CSTOPB | PARENB | CLOCAL);
    tios.c_cflag     |= CS8 | CREAD | HUPCL;

    tios.c_iflag      = IGNBRK | IGNPAR;
    tios.c_oflag      = 0;
    tios.c_lflag      = 0;
    tios.c_cc[VMIN]   = 1;
    tios.c_cc[VTIME]  = 0;

    if (local || !modem)
	tios.c_cflag ^= (CLOCAL | HUPCL);

    switch (crtscts) {
    case 1:
	tios.c_cflag |= CRTSCTS;
	break;

    case -2:
	tios.c_iflag     |= IXON | IXOFF;
	tios.c_cc[VSTOP]  = 0x13;	/* DC3 = XOFF = ^S */
	tios.c_cc[VSTART] = 0x11;	/* DC1 = XON  = ^Q */
	break;

    case -1:
	tios.c_cflag &= ~CRTSCTS;
	break;

    default:
	break;
    }

    speed = translate_speed(inspeed);
    if (speed) {
	cfsetospeed (&tios, speed);
	cfsetispeed (&tios, speed);
    }
/*
 * We can't proceed if the serial port speed is B0,
 * since that implies that the serial port is disabled.
 */
    else {
	speed = cfgetospeed(&tios);
	if (speed == B0)
	    fatal("Baud rate for %s is 0; need explicit baud rate", devnam);
    }

    while (tcsetattr(tty_fd, TCSAFLUSH, &tios) < 0 && !ok_error(errno))
	if (errno != EINTR)
	    fatal("tcsetattr: %m (line %d)", __LINE__);

    baud_rate    = baud_rate_of(speed);
    restore_term = 1;
}

/********************************************************************
 *
 * setdtr - control the DTR line on the serial port.
 * This is called from die(), so it shouldn't call die().
 */

void setdtr (int tty_fd, int on)
{
    int modembits = TIOCM_DTR;

    ioctl(tty_fd, (on ? TIOCMBIS : TIOCMBIC), &modembits);
}

/********************************************************************
 *
 * restore_tty - restore the terminal to the saved settings.
 */

void restore_tty (int tty_fd)
{
    if (restore_term) {
	restore_term = 0;
/*
 * Turn off echoing, because otherwise we can get into
 * a loop with the tty and the modem echoing to each other.
 * We presume we are the sole user of this tty device, so
 * when we close it, it will revert to its defaults anyway.
 */
	if (!default_device)
	    inittermios.c_lflag &= ~(ECHO | ECHONL);

	if (tcsetattr(tty_fd, TCSAFLUSH, &inittermios) < 0) {
	    if (! ok_error (errno))
		warn("tcsetattr: %m (line %d)", __LINE__);
	}
    }
}

/********************************************************************
 *
 * output - Output PPP packet.
 */

void output (int unit, unsigned char *p, int len)
{
    int fd = ppp_fd;
    int proto;

    dump_packet("sent", p, len);
    if (snoop_send_hook) snoop_send_hook(p, len);

    if (len < PPP_HDRLEN)
	return;
    if (new_style_driver) {
	p += 2;
	len -= 2;
	proto = (p[0] << 8) + p[1];
	if (ppp_dev_fd >= 0 && !(proto >= 0xc000 || proto == PPP_CCPFRAG))
	    fd = ppp_dev_fd;
    }
    if (write(fd, p, len) < 0) {
	if (errno == EWOULDBLOCK || errno == EAGAIN || errno == ENOBUFS
	    || errno == ENXIO || errno == EIO || errno == EINTR)
	    warn("write: warning: %m (%d)", errno);
	else
	    error("write: %m (%d)", errno);
    }
}

/********************************************************************
 *
 * wait_input - wait until there is data available,
 * for the length of time specified by *timo (indefinite
 * if timo is NULL).
 */

void wait_input(struct timeval *timo)
{
    fd_set ready, exc;
    int n;

    ready = in_fds;
    exc = in_fds;
    n = select(max_in_fd + 1, &ready, NULL, &exc, timo);
    if (n < 0 && errno != EINTR)
	fatal("select: %m");
}