sys-linux.c

来自「经典的ppp程序」· C语言 代码 · 共 2,629 行 · 第 1/5 页

	}
    }
    initfdflags = -1;

    if (new_style_driver) {
	close(ppp_fd);
	ppp_fd = -1;
	if (!looped && ifunit >= 0 && ioctl(ppp_dev_fd, PPPIOCDETACH) < 0)
	    error("Couldn't release PPP unit: %m");
	if (!multilink)
	    remove_fd(ppp_dev_fd);
    }
}

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

	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");
		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)
{
	int flags;

	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");
	flags = get_flags(ppp_dev_fd);
	flags &= ~(SC_MP_SHORTSEQ | SC_MP_XSHORTSEQ);
	flags |= (rssn? SC_MP_SHORTSEQ: 0) | (tssn? SC_MP_XSHORTSEQ: 0)
		| (mrru? SC_MULTILINK: 0);

	set_flags(ppp_dev_fd, flags);

	/* 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)
{
	if (!new_style_driver)
		return -1;

	if (ioctl(ppp_dev_fd, PPPIOCATTACH, &ifnum) < 0) {
		if (errno == ENXIO)
			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);
	set_flags(ppp_dev_fd, get_flags(ppp_dev_fd) | SC_MULTILINK);

	ifunit = ifnum;
	return 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(%d)", errno);
	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);
    }

    if (tcsetattr(tty_fd, TCSAFLUSH, &tios) < 0)
	if (!ok_error(errno))
	    fatal("tcsetattr: %m");
    
    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");
	}
    }
}

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

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

    if (debug){
	dbglog("sent %P", p, len);
    }
    if (len < PPP_HDRLEN){
	return;
    }
    if (new_style_driver) {
	p += 2;
	len -= 2;
	proto = (p[0] << 8) + p[1];
	if (ifunit >= 0 && !(proto >= 0xc000 || proto == PPP_CCPFRAG))
	    fd = ppp_dev_fd;
    }
    if (write(fd, p, len) < 0) {
	if (errno == EWOULDBLOCK || 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(%d)", errno);
}

/*
 * add_fd - add an fd to the set that wait_input waits for.
 */
void add_fd(int fd)
{
    FD_SET(fd, &in_fds);
    if (fd > max_in_fd)
	max_in_fd = fd;
}

/*
 * remove_fd - remove an fd from the set that wait_input waits for.
 */
void remove_fd(int fd)
{
    FD_CLR(fd, &in_fds);
}


/********************************************************************
 *
 * read_packet - get a PPP packet from the serial device.
 */

int read_packet (unsigned char *buf)
{
    int len, nr;

    len = PPP_MRU + PPP_HDRLEN;
    if (new_style_driver) {
	*buf++ = PPP_ALLSTATIONS;
	*buf++ = PPP_UI;
	len -= 2;
    }
    nr = -1;
    if (ppp_fd >= 0) {
	nr = read(ppp_fd, buf, len);
	if (nr < 0 && errno != EWOULDBLOCK && errno != EIO && errno != EINTR)
	    error("read: %m");
	if (nr < 0 && errno == ENXIO)
	    return 0;
    }
    if (nr < 0 && new_style_driver && ifunit >= 0) {
	/* N.B. we read ppp_fd first since LCP packets come in there. */
	nr = read(ppp_dev_fd, buf, len);
	if (nr < 0 && errno != EWOULDBLOCK && errno != EIO && errno != EINTR)
	    error("read /dev/ppp: %m");
	if (nr < 0 && errno == ENXIO)
	    return 0;
    }
    return (new_style_driver && nr > 0)? nr+2: nr;
}

/********************************************************************
 *
 * get_loop_output - get outgoing packets from the ppp device,
 * and detect when we want to bring the real link up.
 * Return value is 1 if we need to bring up the link, 0 otherwise.
 */
int
get_loop_output(void)
{
    int rv = 0;
    int n;

    if (new_style_driver) {
	while ((n = read_packet(inpacket_buf)) > 0)
	    if (loop_frame(inpacket_buf, n))
		rv = 1;
	return rv;
    }

    while ((n = read(master_fd, inbuf, sizeof(inbuf))) > 0)
	if (loop_chars(inbuf, n))
	    rv = 1;

    if (n == 0)
	fatal("eof on loopback");

    if (errno != EWOULDBLOCK)
	fatal("read from loopback: %m(%d)", errno);

    return rv;
}

/*
 * netif_set_mtu - set the MTU on the PPP network interface.
 */
void
netif_set_mtu(int unit, int mtu)
{
    struct ifreq ifr;