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

/*
 * sys-linux.c - System-dependent procedures for setting up
 * PPP interfaces on Linux systems
 *
 * Copyright (c) 1994-2004 Paul Mackerras. 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. The name(s) of the authors of this software must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission.
 *
 * 3. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by Paul Mackerras
 *     <[e-mail]>".
 *
 * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS, IN NO EVENT SHALL THE AUTHORS 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.
 *
 * Derived from main.c and pppd.h, which are:
 *
 * 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.
 */

#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/errno.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/utsname.h>
#include <sys/sysmacros.h>

#include <stdio.h>
#include <stdlib.h>
#include <syslog.h>
#include <string.h>
#include <time.h>
#include <memory.h>
#include <utmp.h>
#include <mntent.h>
#include <signal.h>
#include <fcntl.h>
#include <ctype.h>
#include <termios.h>
#include <unistd.h>

/* This is in netdevice.h. However, this compile will fail miserably if
   you attempt to include netdevice.h because it has so many references
   to __memcpy functions which it should not attempt to do. So, since I
   really don't use it, but it must be defined, define it now. */

#ifndef MAX_ADDR_LEN
#define MAX_ADDR_LEN 7
#endif

#if __GLIBC__ >= 2
#include <asm/types.h>		/* glibc 2 conflicts with linux/types.h */
#include <net/if.h>
#include <net/if_arp.h>
#include <net/route.h>
#include <netinet/if_ether.h>
#else
#include <linux/types.h>
#include <linux/if.h>
#include <linux/if_arp.h>
#include <linux/route.h>
#include <linux/if_ether.h>
#endif
#include <netinet/in.h>
#include <arpa/inet.h>

#include <linux/ppp_defs.h>
#include <linux/if_ppp.h>

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

#ifdef IPX_CHANGE
#include "ipxcp.h"
#if __GLIBC__ >= 2 && \
    !(defined(__powerpc__) && __GLIBC__ == 2 && __GLIBC_MINOR__ == 0)
#include <netipx/ipx.h>
#else
#include <linux/ipx.h>
#endif
#endif /* IPX_CHANGE */

#ifdef PPP_FILTER
#include <pcap-bpf.h>
#include <linux/filter.h>
#endif /* PPP_FILTER */

#ifdef LOCKLIB
#include <sys/locks.h>
#endif

#ifdef INET6
#ifndef _LINUX_IN6_H
/*
 *    This is in linux/include/net/ipv6.h.
 */

struct in6_ifreq {
    struct in6_addr ifr6_addr;
    __u32 ifr6_prefixlen;
    unsigned int ifr6_ifindex;
};
#endif

#define IN6_LLADDR_FROM_EUI64(sin6, eui64) do {			\
	memset(&sin6.s6_addr, 0, sizeof(struct in6_addr));	\
	sin6.s6_addr16[0] = htons(0xfe80);			\
	eui64_copy(eui64, sin6.s6_addr32[2]);			\
	} while (0)

#endif /* INET6 */

/* We can get an EIO error on an ioctl if the modem has hung up */
#define ok_error(num) ((num)==EIO)

static int tty_disc = N_TTY;	/* The TTY discipline */
static int ppp_disc = N_PPP;	/* The PPP discpline */
static int initfdflags = -1;	/* Initial file descriptor flags for fd */
static int ppp_fd = -1;		/* fd which is set to PPP discipline */
static int sock_fd = -1;	/* socket for doing interface ioctls */
static int slave_fd = -1;	/* pty for old-style demand mode, slave */
static int master_fd = -1;	/* pty for old-style demand mode, master */
#ifdef INET6
static int sock6_fd = -1;
#endif /* INET6 */

/*
 * For the old-style kernel driver, this is the same as ppp_fd.
 * For the new-style driver, it is the fd of an instance of /dev/ppp
 * which is attached to the ppp unit and is used for controlling it.
 */
int ppp_dev_fd = -1;		/* fd for /dev/ppp (new style driver) */

static int chindex;		/* channel index (new style driver) */

static fd_set in_fds;		/* set of fds that wait_input waits for */
static int max_in_fd;		/* highest fd set in in_fds */

static int has_proxy_arp       = 0;
static int driver_version      = 0;
static int driver_modification = 0;
static int driver_patch        = 0;
static int driver_is_old       = 0;
static int restore_term        = 0;	/* 1 => we've munged the terminal */
static struct termios inittermios;	/* Initial TTY termios */

int new_style_driver = 0;

static char loop_name[20];
static unsigned char inbuf[512]; /* buffer for chars read from loopback */

static int	if_is_up;	/* Interface has been marked up */
static int	have_default_route;	/* Gateway for default route added */
static u_int32_t proxy_arp_addr;	/* Addr for proxy arp entry added */
static char proxy_arp_dev[16];		/* Device for proxy arp entry */
static u_int32_t our_old_addr;		/* for detecting address changes */
static int	dynaddr_set;		/* 1 if ip_dynaddr set */
static int	looped;			/* 1 if using loop */
static int	link_mtu;		/* mtu for the link (not bundle) */

static struct utsname utsname;	/* for the kernel version */
static int kernel_version;
#define KVERSION(j,n,p)	((j)*1000000 + (n)*1000 + (p))

#define MAX_IFS		100

#define FLAGS_GOOD (IFF_UP          | IFF_BROADCAST)
#define FLAGS_MASK (IFF_UP          | IFF_BROADCAST | \
		    IFF_POINTOPOINT | IFF_LOOPBACK  | IFF_NOARP)

#define SIN_ADDR(x)	(((struct sockaddr_in *) (&(x)))->sin_addr.s_addr)

/* Prototypes for procedures local to this file. */
static int modify_flags(int fd, int clear_bits, int set_bits);
static int translate_speed (int bps);
static int baud_rate_of (int speed);
static void close_route_table (void);
static int open_route_table (void);
static int read_route_table (struct rtentry *rt);
static int defaultroute_exists (struct rtentry *rt);
static int get_ether_addr (u_int32_t ipaddr, struct sockaddr *hwaddr,
			   char *name, int namelen);
static void decode_version (char *buf, int *version, int *mod, int *patch);
static int set_kdebugflag(int level);
static int ppp_registered(void);
static int make_ppp_unit(void);

extern u_char	inpacket_buf[];	/* borrowed from main.c */

/*
 * SET_SA_FAMILY - set the sa_family field of a struct sockaddr,
 * if it exists.
 */

#define SET_SA_FAMILY(addr, family)			\
    memset ((char *) &(addr), '\0', sizeof(addr));	\
    addr.sa_family = (family);

/*
 * Determine if the PPP connection should still be present.
 */

extern int hungup;

/* new_fd is the fd of a tty */
static void set_ppp_fd (int new_fd)
{
	ppp_fd = new_fd;
	if (!new_style_driver)
		ppp_dev_fd = new_fd;
}

static int still_ppp(void)
{
	if (new_style_driver)
		return !hungup && ppp_fd >= 0;
	if (!hungup || ppp_fd == slave_fd)
		return 1;
	if (slave_fd >= 0) {
		set_ppp_fd(slave_fd);
		return 1;
	}
	return 0;
}

/*
 * modify_flags - set and clear flag bits controlling the kernel
 * PPP driver.
 */
static int modify_flags(int fd, int clear_bits, int set_bits)
{
	int flags;

	if (ioctl(fd, PPPIOCGFLAGS, &flags) == -1)
		goto err;
	flags = (flags & ~clear_bits) | set_bits;
	if (ioctl(fd, PPPIOCSFLAGS, &flags) == -1)
		goto err;

	return 0;

 err:
	if (errno != EIO)
		error("Failed to set PPP kernel option flags: %m");
	return -1;
}

/********************************************************************
 *
 * sys_init - System-dependent initialization.
 */

void sys_init(void)
{
    /* Get an internet socket for doing socket ioctls. */
    sock_fd = socket(AF_INET, SOCK_DGRAM, 0);
    if (sock_fd < 0)
	fatal("Couldn't create IP socket: %m(%d)", errno);

#ifdef INET6
    sock6_fd = socket(AF_INET6, SOCK_DGRAM, 0);
    if (sock6_fd < 0)
	sock6_fd = -errno;	/* save errno for later */
#endif

    FD_ZERO(&in_fds);
    max_in_fd = 0;
}

/********************************************************************
 *
 * sys_cleanup - restore any system state we modified before exiting:
 * mark the interface down, delete default route and/or proxy arp entry.
 * This shouldn't call die() because it's called from die().
 */

void sys_cleanup(void)
{
/*
 * Take down the device
 */
    if (if_is_up) {
	if_is_up = 0;
	sifdown(0);
    }
/*
 * Delete any routes through the device.
 */
    if (have_default_route)
	cifdefaultroute(0, 0, 0);

    if (has_proxy_arp)
	cifproxyarp(0, proxy_arp_addr);
}

/********************************************************************
 *
 * sys_close - Clean up in a child process before execing.
 */
void
sys_close(void)
{
    if (new_style_driver && ppp_dev_fd >= 0)
	close(ppp_dev_fd);
    if (sock_fd >= 0)
	close(sock_fd);
#ifdef INET6
    if (sock6_fd >= 0)
	close(sock6_fd);
#endif
    if (slave_fd >= 0)
	close(slave_fd);
    if (master_fd >= 0)
	close(master_fd);
}

/********************************************************************
 *
 * set_kdebugflag - Define the debugging level for the kernel
 */

static int set_kdebugflag (int requested_level)
{
    if (ppp_dev_fd < 0)
	return 1;
    if (ioctl(ppp_dev_fd, PPPIOCSDEBUG, &requested_level) < 0) {
	if ( ! ok_error (errno) )
	    error("ioctl(PPPIOCSDEBUG): %m (line %d)", __LINE__);
	return (0);
    }
    return (1);
}

/********************************************************************
 *
 * tty_establish_ppp - Turn the serial port into a ppp interface.
 */

int tty_establish_ppp (int tty_fd)
{
    int ret_fd;

/*
 * Ensure that the tty device is in exclusive mode.
 */
    if (ioctl(tty_fd, TIOCEXCL, 0) < 0) {
	if ( ! ok_error ( errno ))
	    warn("Couldn't make tty exclusive: %m");
    }
/*
 * Demand mode - prime the old ppp device to relinquish the unit.
 */
    if (!new_style_driver && looped
	&& ioctl(slave_fd, PPPIOCXFERUNIT, 0) < 0) {
	error("ioctl(transfer ppp unit): %m, line %d", __LINE__);
	return -1;
    }
/*
 * Set the current tty to the PPP discpline
 */

#ifndef N_SYNC_PPP
#define N_SYNC_PPP 14
#endif
    ppp_disc = (new_style_driver && sync_serial)? N_SYNC_PPP: N_PPP;
    if (ioctl(tty_fd, TIOCSETD, &ppp_disc) < 0) {
	if ( ! ok_error (errno) ) {
	    error("Couldn't set tty to PPP discipline: %m");
	    return -1;
	}
    }

    ret_fd = generic_establish_ppp(tty_fd);

#define SC_RCVB	(SC_RCV_B7_0 | SC_RCV_B7_1 | SC_RCV_EVNP | SC_RCV_ODDP)
#define SC_LOGB	(SC_DEBUG | SC_LOG_INPKT | SC_LOG_OUTPKT | SC_LOG_RAWIN \
		 | SC_LOG_FLUSH)

    if (ret_fd >= 0) {
	modify_flags(ppp_fd, SC_RCVB | SC_LOGB,
		     (kdebugflag * SC_DEBUG) & SC_LOGB);
    } else {
	if (ioctl(tty_fd, TIOCSETD, &tty_disc) < 0 && !ok_error(errno))
	    warn("Couldn't reset tty to normal line discipline: %m");
    }

    return ret_fd;
}

/********************************************************************
 *
 * generic_establish_ppp - Turn the fd into a ppp interface.
 */
int generic_establish_ppp (int fd)
{
    int x;

    if (new_style_driver) {
	int flags;

	/* Open an instance of /dev/ppp and connect the channel to it */
	if (ioctl(fd, PPPIOCGCHAN, &chindex) == -1) {
	    error("Couldn't get channel number: %m");
	    goto err;
	}
	dbglog("using channel %d", chindex);
	fd = open("/dev/ppp", O_RDWR);
	if (fd < 0) {
	    error("Couldn't reopen /dev/ppp: %m");
	    goto err;
	}
	(void) fcntl(fd, F_SETFD, FD_CLOEXEC);
	if (ioctl(fd, PPPIOCATTCHAN, &chindex) < 0) {
	    error("Couldn't attach to channel %d: %m", chindex);
	    goto err_close;
	}
	flags = fcntl(fd, F_GETFL);
	if (flags == -1 || fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1)
	    warn("Couldn't set /dev/ppp (channel) to nonblock: %m");
	set_ppp_fd(fd);

	if (!looped)
	    ifunit = -1;
	if (!looped && !multilink) {
	    /*
	     * Create a new PPP unit.
	     */
	    if (make_ppp_unit() < 0)
		goto err_close;
	}

	if (looped)
	    modify_flags(ppp_dev_fd, SC_LOOP_TRAFFIC, 0);

	if (!multilink) {
	    add_fd(ppp_dev_fd);
	    if (ioctl(fd, PPPIOCCONNECT, &ifunit) < 0) {
		error("Couldn't attach to PPP unit %d: %m", ifunit);
		goto err_close;
	    }
	}

    } else {
	/*
	 * Old-style driver: find out which interface we were given.
	 */
	set_ppp_fd (fd);
	if (ioctl(fd, PPPIOCGUNIT, &x) < 0) {
	    if (ok_error (errno))
		goto err;
	    fatal("ioctl(PPPIOCGUNIT): %m (line %d)", __LINE__);
	}
	/* Check that we got the same unit again. */
	if (looped && x != ifunit)
	    fatal("transfer_ppp failed: wanted unit %d, got %d", ifunit, x);
	ifunit = x;

	/*
	 * Fetch the initial file flags and reset blocking mode on the file.
	 */
	initfdflags = fcntl(fd, F_GETFL);
	if (initfdflags == -1 ||
	    fcntl(fd, F_SETFL, initfdflags | O_NONBLOCK) == -1) {
	    if ( ! ok_error (errno))
		warn("Couldn't set device to non-blocking mode: %m");
	}
    }

    /*
     * Enable debug in the driver if requested.
     */
    if (!looped)