ifenslave.c

《嵌入式系统设计与实例开发实验教材二源码》Linux内核移植与编译实验

/* Mode: C;
 * ifenslave.c: Configure network interfaces for parallel routing.
 *
 *	This program controls the Linux implementation of running multiple
 *	network interfaces in parallel.
 *
 * Usage:	ifenslave [-v] master-interface < slave-interface [metric <N>] > ...
 *
 * Author:	Donald Becker <[e-mail]>
 *		Copyright 1994-1996 Donald Becker
 *
 *		This program is free software; you can redistribute it
 *		and/or modify it under the terms of the GNU General Public
 *		License as published by the Free Software Foundation.
 *
 *	The author may be reached as [e-mail], or C/O
 *	Center of Excellence in Space Data and Information Sciences
 *	   Code 930.5, Goddard Space Flight Center, Greenbelt MD 20771
 *
 *  Changes :
 *    - 2000/10/02 Willy Tarreau <willy at meta-x.org> :
 *       - few fixes. Master's MAC address is now correctly taken from
 *         the first device when not previously set ;
 *       - detach support : call BOND_RELEASE to detach an enslaved interface.
 *       - give a mini-howto from command-line help : # ifenslave -h
 *
 *    - 2001/02/16 Chad N. Tindel <ctindel at ieee dot org> :
 *       - Master is now brought down before setting the MAC address.  In
 *         the 2.4 kernel you can't change the MAC address while the device is
 *         up because you get EBUSY.  
 *
 *    - 2001/09/13 Takao Indoh <indou dot takao at jp dot fujitsu dot com>
 *       - Added the ability to change the active interface on a mode 1 bond
 *         at runtime.
 *
 *    - 2001/10/23 Chad N. Tindel <ctindel at ieee dot org> :
 *       - No longer set the MAC address of the master.  The bond device will
 *         take care of this itself
 *       - Try the SIOC*** versions of the bonding ioctls before using the
 *         old versions
 */

static char *version =
"ifenslave.c:v0.07 9/9/97  Donald Becker ([e-mail]).\n"
"detach support added on 2000/10/02 by Willy Tarreau (willy at meta-x.org).\n"
"2.4 kernel support added on 2001/02/16 by Chad N. Tindel (ctindel at ieee dot org.\n";

static const char *usage_msg =
"Usage: ifenslave [-adfrvVh] <master-interface> < <slave-if> [metric <N>] > ...\n"
"       ifenslave -c master-interface slave-if\n";

static const char *howto_msg =
"Usage: ifenslave [-adfrvVh] <master-interface> < <slave-if> [metric <N>] > ...\n"
"       ifenslave -c master-interface slave-if\n"
"\n"
"       To create a bond device, simply follow these three steps :\n"
"       - ensure that the required drivers are properly loaded :\n"
"         # modprobe bonding ; modprobe <3c59x|eepro100|pcnet32|tulip|...>\n"
"       - assign an IP address to the bond device :\n"
"         # ifconfig bond0 <addr> netmask <mask> broadcast <bcast>\n"
"       - attach all the interfaces you need to the bond device :\n"
"         # ifenslave bond0 eth0 eth1 eth2\n"
"         If bond0 didn't have a MAC address, it will take eth0's. Then, all\n"
"         interfaces attached AFTER this assignment will get the same MAC addr.\n"
"\n"
"       To detach a dead interface without setting the bond device down :\n"
"         # ifenslave -d bond0 eth1\n"
"\n"
"       To set the bond device down and automatically release all the slaves :\n"
"         # ifconfig bond0 down\n"
"\n"
"       To change active slave :\n"
"         # ifenslave -c bond0 eth0\n"
"\n";

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <linux/if.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>
#include <linux/if_bonding.h>
#include <linux/sockios.h>

struct option longopts[] = {
 /* { name  has_arg  *flag  val } */
    {"all-interfaces", 0, 0, 'a'},	/* Show all interfaces. */
    {"force",       0, 0, 'f'},		/* Force the operation. */
    {"help", 		0, 0, '?'},		/* Give help */
	{"howto",       0, 0, 'h'},     /* Give some more help */
    {"receive-slave", 0, 0, 'r'},	/* Make a receive-only slave.  */
    {"verbose", 	0, 0, 'v'},		/* Report each action taken.  */
    {"version", 	0, 0, 'V'},		/* Emit version information.  */
    {"detach",       0, 0, 'd'},	/* Detach a slave interface. */
    {"change-active", 0, 0, 'c'},	/* Change the active slave.  */
    { 0, 0, 0, 0 }
};

/* Command-line flags. */
unsigned int
opt_a = 0,					/* Show-all-interfaces flag. */
opt_f = 0,					/* Force the operation. */
opt_r = 0,					/* Set up a Rx-only slave. */
opt_d = 0,					/* detach a slave interface. */
opt_c = 0,					/* change-active-slave flag. */
verbose = 0,					/* Verbose flag. */
opt_version = 0,
opt_howto = 0;
int skfd = -1;					/* AF_INET socket for ioctl() calls.	*/

static void if_print(char *ifname);

int
main(int argc, char **argv)
{
	struct ifreq  ifr2, if_hwaddr, if_ipaddr, if_metric, if_mtu, if_dstaddr;
	struct ifreq  if_netmask, if_brdaddr, if_flags;
	int goterr = 0;
	int c, errflag = 0;
	sa_family_t master_family;
	char **spp, *master_ifname, *slave_ifname;
	int hwaddr_notset;

	while ((c = getopt_long(argc, argv, "acdfrvV?h", longopts, 0)) != EOF)
		switch (c) {
		case 'a': opt_a++; break;
		case 'f': opt_f++; break;
		case 'r': opt_r++; break;
		case 'd': opt_d++; break;
		case 'c': opt_c++; break;
		case 'v': verbose++;		break;
		case 'V': opt_version++;	break;
		case 'h': opt_howto++;	break;
		case '?': errflag++;
		}

	/* option check */
	if (opt_c)
		if(opt_a || opt_f || opt_r || opt_d || verbose || opt_version ||
		   opt_howto || errflag ) {
			fprintf(stderr, usage_msg);
			return 2;
		}

	if (errflag) {
		fprintf(stderr, usage_msg);
		return 2;
	}

	if (opt_howto) {
		fprintf(stderr, howto_msg);
		return 0;
	}

	if (verbose || opt_version) {
		printf(version);
		if (opt_version)
			exit(0);
	}

	/* Open a basic socket. */
	if ((skfd = socket(AF_INET, SOCK_DGRAM,0)) < 0) {
		perror("socket");
		exit(-1);
	}

	if (verbose)
		fprintf(stderr, "DEBUG: argc=%d, optind=%d and argv[optind] is %s.\n",
				argc, optind, argv[optind]);

	/* No remaining args means show all interfaces. */
	if (optind == argc) {
		if_print((char *)NULL);
		(void) close(skfd);
		exit(0);
	}

	/* Copy the interface name. */
	spp = argv + optind;
	master_ifname = *spp++;
	slave_ifname = *spp++;

	/* Check command line. */
	if (opt_c) {
		char **tempp = spp;
		if ((master_ifname == NULL)||(slave_ifname == NULL)||(*tempp++ != NULL)) {
			fprintf(stderr, usage_msg);
			return 2;
		}
	}

	/* A single args means show the configuration for this interface. */
	if (slave_ifname == NULL) {
		if_print(master_ifname);
		(void) close(skfd);
		exit(0);
	}

	/* Get the vitals from the master interface. */
	{
		struct ifreq *ifra[7] = { &if_ipaddr, &if_mtu, &if_dstaddr,
								  &if_brdaddr, &if_netmask, &if_flags,
								  &if_hwaddr };
		const char *req_name[7] = {
			"IP address", "MTU", "destination address",
			"broadcast address", "netmask", "status flags",
			"hardware address" };
		const int ioctl_req_type[7] = {
			SIOCGIFADDR, SIOCGIFMTU, SIOCGIFDSTADDR,
			SIOCGIFBRDADDR, SIOCGIFNETMASK, SIOCGIFFLAGS,
			SIOCGIFHWADDR };
		int i;

		for (i = 0; i < 7; i++) {
			strncpy(ifra[i]->ifr_name, master_ifname, IFNAMSIZ);
			if (ioctl(skfd, ioctl_req_type[i], ifra[i]) < 0) {
				fprintf(stderr,
						"Something broke getting the master's %s: %s.\n",
						req_name[i], strerror(errno));
			}
		}

		hwaddr_notset = 1; /* assume master's address not set yet */
		for (i = 0; hwaddr_notset && (i < 6); i++) {
			hwaddr_notset &= ((unsigned char *)if_hwaddr.ifr_hwaddr.sa_data)[i] == 0;
		}

		/* The family '1' is ARPHRD_ETHER for ethernet. */
		if (if_hwaddr.ifr_hwaddr.sa_family != 1 && !opt_f) {
			fprintf(stderr, "The specified master interface '%s' is not"
					" ethernet-like.\n  This program is designed to work"
					" with ethernet-like network interfaces.\n"
					" Use the '-f' option to force the operation.\n",
					master_ifname);

			exit (1);
		}
		master_family = if_hwaddr.ifr_hwaddr.sa_family;
		if (verbose) {
			unsigned char *hwaddr = (unsigned char *)if_hwaddr.ifr_hwaddr.sa_data;
			printf("The current hardware address (SIOCGIFHWADDR) of %s is type %d  "
				   "%2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x.\n", master_ifname,
				   if_hwaddr.ifr_hwaddr.sa_family, hwaddr[0], hwaddr[1],
				   hwaddr[2], hwaddr[3], hwaddr[4], hwaddr[5]);
		}
	}


	/* do this when enslaving interfaces */
	do {
		if (opt_d) {  /* detach a slave interface from the master */
			strncpy(if_flags.ifr_name, master_ifname, IFNAMSIZ);
			strncpy(if_flags.ifr_slave, slave_ifname, IFNAMSIZ);
			if ((ioctl(skfd, SIOCBONDRELEASE, &if_flags) < 0) &&
				(ioctl(skfd, BOND_RELEASE_OLD, &if_flags) < 0)) {
					fprintf(stderr,	"SIOCBONDRELEASE: cannot detach %s from %s. errno=%s.\n",
							slave_ifname, master_ifname, strerror(errno));
			}
			else {  /* we'll set the interface down to avoid any conflicts due to
					   same IP/MAC */
				strncpy(ifr2.ifr_name, slave_ifname, IFNAMSIZ);
				if (ioctl(skfd, SIOCGIFFLAGS, &ifr2) < 0) {
					int saved_errno = errno;
					fprintf(stderr, "SIOCGIFFLAGS on %s failed: %s\n", slave_ifname,
							strerror(saved_errno));
				}
				else {
					ifr2.ifr_flags &= ~(IFF_UP | IFF_RUNNING);
					if (ioctl(skfd, SIOCSIFFLAGS, &ifr2) < 0) {
						int saved_errno = errno;
						fprintf(stderr, "Shutting down interface %s failed: %s\n",
								slave_ifname, strerror(saved_errno));
					}
				}