[PATCH] NLM: Ensure we do not Oops in the case of an unlock

[linux/fpc-iii.git] / Documentation / networking / ifenslave.c

/* Mode: C;
 * ifenslave.c: Configure network interfaces for parallel routing.
 *
 *      This program controls the Linux implementation of running multiple
 *      network interfaces in parallel.
 *
 * Author:      Donald Becker <becker@cesdis.gsfc.nasa.gov>
 *              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 becker@CESDIS.gsfc.nasa.gov, 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
 *    - 2002/02/18 Erik Habbinga <erik_habbinga @ hp dot com> :
 *       - ifr2.ifr_flags was not initialized in the hwaddr_notset case,
 *         SIOCGIFFLAGS now called before hwaddr_notset test
 *
 *    - 2002/10/31 Tony Cureington <tony.cureington * hp_com> :
 *       - If the master does not have a hardware address when the first slave
 *         is enslaved, the master is assigned the hardware address of that
 *         slave - there is a comment in bonding.c stating "ifenslave takes
 *         care of this now." This corrects the problem of slaves having
 *         different hardware addresses in active-backup mode when
 *         multiple interfaces are specified on a single ifenslave command
 *         (ifenslave bond0 eth0 eth1).
 *
 *    - 2003/03/18 - Tsippy Mendelson <tsippy.mendelson at intel dot com> and
 *                   Shmulik Hen <shmulik.hen at intel dot com>
 *       - Moved setting the slave's mac address and openning it, from
 *         the application to the driver. This enables support of modes
 *         that need to use the unique mac address of each slave.
 *         The driver also takes care of closing the slave and restoring its
 *         original mac address upon release.
 *         In addition, block possibility of enslaving before the master is up.
 *         This prevents putting the system in an undefined state.
 *
 *    - 2003/05/01 - Amir Noam <amir.noam at intel dot com>
 *       - Added ABI version control to restore compatibility between
 *         new/old ifenslave and new/old bonding.
 *       - Prevent adding an adapter that is already a slave.
 *         Fixes the problem of stalling the transmission and leaving
 *         the slave in a down state.
 *
 *    - 2003/05/01 - Shmulik Hen <shmulik.hen at intel dot com>
 *       - Prevent enslaving if the bond device is down.
 *         Fixes the problem of leaving the system in unstable state and
 *         halting when trying to remove the module.
 *       - Close socket on all abnormal exists.
 *       - Add versioning scheme that follows that of the bonding driver.
 *         current version is 1.0.0 as a base line.
 *
 *    - 2003/05/22 - Jay Vosburgh <fubar at us dot ibm dot com>
 *       - ifenslave -c was broken; it's now fixed
 *       - Fixed problem with routes vanishing from master during enslave
 *         processing.
 *
 *    - 2003/05/27 - Amir Noam <amir.noam at intel dot com>
 *       - Fix backward compatibility issues:
 *         For drivers not using ABI versions, slave was set down while
 *         it should be left up before enslaving.
 *         Also, master was not set down and the default set_mac_address()
 *         would fail and generate an error message in the system log.
 *       - For opt_c: slave should not be set to the master's setting
 *         while it is running. It was already set during enslave. To
 *         simplify things, it is now handeled separately.
 *
 *    - 2003/12/01 - Shmulik Hen <shmulik.hen at intel dot com>
 *       - Code cleanup and style changes
 *         set version to 1.1.0
 */

#define APP_VERSION     "1.1.0"
#define APP_RELDATE     "December 1, 2003"
#define APP_NAME        "ifenslave"

static char *version =
APP_NAME ".c:v" APP_VERSION " (" APP_RELDATE ")\n"
"o Donald Becker (becker@cesdis.gsfc.nasa.gov).\n"
"o Detach support added on 2000/10/02 by Willy Tarreau (willy at meta-x.org).\n"
"o 2.4 kernel support added on 2001/02/16 by Chad N. Tindel\n"
"  (ctindel at ieee dot org).\n";

static const char *usage_msg =
"Usage: ifenslave [-f] <master-if> <slave-if> [<slave-if>...]\n"
"       ifenslave -d   <master-if> <slave-if> [<slave-if>...]\n"
"       ifenslave -c   <master-if> <slave-if>\n"
"       ifenslave --help\n";

static const char *help_msg =
"\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 [{-f|--force}] 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"
"         (except for ALB/TLB modes)\n"
"\n"
"       To set the bond device down and automatically release all the slaves :\n"
"         # ifconfig bond0 down\n"
"\n"
"       To detach a dead interface without setting the bond device down :\n"
"         # ifenslave {-d|--detach} bond0 eth0 [eth1 [eth2]...]\n"
"\n"
"       To change active slave :\n"
"         # ifenslave {-c|--change-active} bond0 eth0\n"
"\n"
"       To show master interface info\n"
"         # ifenslave bond0\n"
"\n"
"       To show all interfaces info\n"
"       # ifenslave {-a|--all-interfaces}\n"
"\n"
"       To be more verbose\n"
"       # ifenslave {-v|--verbose} ...\n"
"\n"
"       # ifenslave {-u|--usage}   Show usage\n"
"       # ifenslave {-V|--version} Show version\n"
"       # ifenslave {-h|--help}    This message\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 <net/if_arp.h>
#include <linux/if_ether.h>
#include <linux/if_bonding.h>
#include <linux/sockios.h>

typedef unsigned long long u64; /* hack, so we may include kernel's ethtool.h */
typedef __uint32_t u32;         /* ditto */
typedef __uint16_t u16;         /* ditto */
typedef __uint8_t u8;           /* ditto */
#include <linux/ethtool.h>

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

/* Command-line flags. */
unsigned int
opt_a = 0,      /* Show-all-interfaces flag. */
opt_c = 0,      /* Change-active-slave flag. */
opt_d = 0,      /* Detach a slave interface. */
opt_f = 0,      /* Force the operation. */
opt_h = 0,      /* Help */
opt_u = 0,      /* Usage */
opt_v = 0,      /* Verbose flag. */
opt_V = 0;      /* Version */

int skfd = -1;          /* AF_INET socket for ioctl() calls.*/
int abi_ver = 0;        /* userland - kernel ABI version */
int hwaddr_set = 0;     /* Master's hwaddr is set */
int saved_errno;

struct ifreq master_mtu, master_flags, master_hwaddr;
struct ifreq slave_mtu, slave_flags, slave_hwaddr;

struct dev_ifr {
        struct ifreq *req_ifr;
        char *req_name;
        int req_type;
};

struct dev_ifr master_ifra[] = {
        {&master_mtu,     "SIOCGIFMTU",     SIOCGIFMTU},
        {&master_flags,   "SIOCGIFFLAGS",   SIOCGIFFLAGS},
        {&master_hwaddr,  "SIOCGIFHWADDR",  SIOCGIFHWADDR},
        {NULL, "", 0}
};

struct dev_ifr slave_ifra[] = {
        {&slave_mtu,     "SIOCGIFMTU",     SIOCGIFMTU},
        {&slave_flags,   "SIOCGIFFLAGS",   SIOCGIFFLAGS},
        {&slave_hwaddr,  "SIOCGIFHWADDR",  SIOCGIFHWADDR},
        {NULL, "", 0}
};

static void if_print(char *ifname);
static int get_drv_info(char *master_ifname);
static int get_if_settings(char *ifname, struct dev_ifr ifra[]);
static int get_slave_flags(char *slave_ifname);
static int set_master_hwaddr(char *master_ifname, struct sockaddr *hwaddr);
static int set_slave_hwaddr(char *slave_ifname, struct sockaddr *hwaddr);
static int set_slave_mtu(char *slave_ifname, int mtu);
static int set_if_flags(char *ifname, short flags);
static int set_if_up(char *ifname, short flags);
static int set_if_down(char *ifname, short flags);
static int clear_if_addr(char *ifname);
static int set_if_addr(char *master_ifname, char *slave_ifname);
static int change_active(char *master_ifname, char *slave_ifname);
static int enslave(char *master_ifname, char *slave_ifname);
static int release(char *master_ifname, char *slave_ifname);
#define v_print(fmt, args...)   \
        if (opt_v)              \
                fprintf(stderr, fmt, ## args )

int main(int argc, char *argv[])
{
        char **spp, *master_ifname, *slave_ifname;
        int c, i, rv;
        int res = 0;
        int exclusive = 0;

        while ((c = getopt_long(argc, argv, "acdfhuvV", longopts, 0)) != EOF) {
                switch (c) {
                case 'a': opt_a++; exclusive++; break;
                case 'c': opt_c++; exclusive++; break;
                case 'd': opt_d++; exclusive++; break;
                case 'f': opt_f++; exclusive++; break;
                case 'h': opt_h++; exclusive++; break;
                case 'u': opt_u++; exclusive++; break;
                case 'v': opt_v++; break;
                case 'V': opt_V++; exclusive++; break;

                case '?':
                        fprintf(stderr, usage_msg);
                        res = 2;
                        goto out;
                }
        }

        /* options check */
        if (exclusive > 1) {
                fprintf(stderr, usage_msg);
                res = 2;
                goto out;
        }

        if (opt_v || opt_V) {
                printf(version);
                if (opt_V) {
                        res = 0;
                        goto out;
                }
        }

        if (opt_u) {
                printf(usage_msg);
                res = 0;
                goto out;
        }

        if (opt_h) {
                printf(usage_msg);
                printf(help_msg);
                res = 0;
                goto out;
        }

        /* Open a basic socket */
        if ((skfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
                perror("socket");
                res = 1;
                goto out;
        }

        if (opt_a) {
                if (optind == argc) {
                        /* No remaining args */
                        /* show all interfaces */
                        if_print((char *)NULL);
                        goto out;
                } else {
                        /* Just show usage */
                        fprintf(stderr, usage_msg);
                        res = 2;
                        goto out;
                }
        }

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

        if (master_ifname == NULL) {
                fprintf(stderr, usage_msg);
                res = 2;
                goto out;
        }

        /* exchange abi version with bonding module */
        res = get_drv_info(master_ifname);
        if (res) {
                fprintf(stderr,
                        "Master '%s': Error: handshake with driver failed. "
                        "Aborting\n",
                        master_ifname);
                goto out;
        }

        slave_ifname = *spp++;

        if (slave_ifname == NULL) {
                if (opt_d || opt_c) {
                        fprintf(stderr, usage_msg);
                        res = 2;
                        goto out;
                }

                /* A single arg means show the
                 * configuration for this interface
                 */
                if_print(master_ifname);
                goto out;
        }

        res = get_if_settings(master_ifname, master_ifra);
        if (res) {
                /* Probably a good reason not to go on */
                fprintf(stderr,
                        "Master '%s': Error: get settings failed: %s. "
                        "Aborting\n",
                        master_ifname, strerror(res));
                goto out;
        }

        /* check if master is indeed a master;
         * if not then fail any operation
         */
        if (!(master_flags.ifr_flags & IFF_MASTER)) {
                fprintf(stderr,
                        "Illegal operation; the specified interface '%s' "
                        "is not a master. Aborting\n",
                        master_ifname);
                res = 1;
                goto out;
        }

        /* check if master is up; if not then fail any operation */
        if (!(master_flags.ifr_flags & IFF_UP)) {
                fprintf(stderr,
                        "Illegal operation; the specified master interface "
                        "'%s' is not up.\n",
                        master_ifname);
                res = 1;
                goto out;
        }

        /* Only for enslaving */
        if (!opt_c && !opt_d) {
                sa_family_t master_family = master_hwaddr.ifr_hwaddr.sa_family;
                unsigned char *hwaddr =
                        (unsigned char *)master_hwaddr.ifr_hwaddr.sa_data;

                /* The family '1' is ARPHRD_ETHER for ethernet. */
                if (master_family != 1 && !opt_f) {
                        fprintf(stderr,
                                "Illegal operation: 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);
                        res = 1;
                        goto out;
                }

                /* Check master's hw addr */
                for (i = 0; i < 6; i++) {
                        if (hwaddr[i] != 0) {
                                hwaddr_set = 1;
                                break;
                        }
                }

                if (hwaddr_set) {
                        v_print("current hardware address of master '%s' "
                                "is %2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x, "
                                "type %d\n",
                                master_ifname,
                                hwaddr[0], hwaddr[1],
                                hwaddr[2], hwaddr[3],
                                hwaddr[4], hwaddr[5],
                                master_family);
                }
        }

        /* Accepts only one slave */
        if (opt_c) {
                /* change active slave */
                res = get_slave_flags(slave_ifname);
                if (res) {
                        fprintf(stderr,
                                "Slave '%s': Error: get flags failed. "
                                "Aborting\n",
                                slave_ifname);
                        goto out;
                }
                res = change_active(master_ifname, slave_ifname);
                if (res) {
                        fprintf(stderr,
                                "Master '%s', Slave '%s': Error: "
                                "Change active failed\n",
                                master_ifname, slave_ifname);
                }
        } else {
                /* Accept multiple slaves */
                do {
                        if (opt_d) {
                                /* detach a slave interface from the master */
                                rv = get_slave_flags(slave_ifname);
                                if (rv) {
                                        /* Can't work with this slave. */
                                        /* remember the error and skip it*/
                                        fprintf(stderr,
                                                "Slave '%s': Error: get flags "
                                                "failed. Skipping\n",
                                                slave_ifname);
                                        res = rv;
                                        continue;
                                }
                                rv = release(master_ifname, slave_ifname);
                                if (rv) {
                                        fprintf(stderr,
                                                "Master '%s', Slave '%s': Error: "
                                                "Release failed\n",
                                                master_ifname, slave_ifname);
                                        res = rv;
                                }
                        } else {
                                /* attach a slave interface to the master */
                                rv = get_if_settings(slave_ifname, slave_ifra);
                                if (rv) {
                                        /* Can't work with this slave. */
                                        /* remember the error and skip it*/
                                        fprintf(stderr,
                                                "Slave '%s': Error: get "
                                                "settings failed: %s. "
                                                "Skipping\n",
                                                slave_ifname, strerror(rv));
                                        res = rv;
                                        continue;
                                }
                                rv = enslave(master_ifname, slave_ifname);
                                if (rv) {
                                        fprintf(stderr,
                                                "Master '%s', Slave '%s': Error: "
                                                "Enslave failed\n",
                                                master_ifname, slave_ifname);
                                        res = rv;
                                }
                        }
                } while ((slave_ifname = *spp++) != NULL);
        }

out:
        if (skfd >= 0) {
                close(skfd);
        }

        return res;
}

static short mif_flags;

/* Get the inteface configuration from the kernel. */
static int if_getconfig(char *ifname)
{
        struct ifreq ifr;
        int metric, mtu;        /* Parameters of the master interface. */
        struct sockaddr dstaddr, broadaddr, netmask;
        unsigned char *hwaddr;

        strcpy(ifr.ifr_name, ifname);
        if (ioctl(skfd, SIOCGIFFLAGS, &ifr) < 0)
                return -1;
        mif_flags = ifr.ifr_flags;
        printf("The result of SIOCGIFFLAGS on %s is %x.\n",
               ifname, ifr.ifr_flags);

        strcpy(ifr.ifr_name, ifname);
        if (ioctl(skfd, SIOCGIFADDR, &ifr) < 0)
                return -1;
        printf("The result of SIOCGIFADDR is %2.2x.%2.2x.%2.2x.%2.2x.\n",
               ifr.ifr_addr.sa_data[0], ifr.ifr_addr.sa_data[1],
               ifr.ifr_addr.sa_data[2], ifr.ifr_addr.sa_data[3]);

        strcpy(ifr.ifr_name, ifname);
        if (ioctl(skfd, SIOCGIFHWADDR, &ifr) < 0)
                return -1;

        /* Gotta convert from 'char' to unsigned for printf(). */
        hwaddr = (unsigned char *)ifr.ifr_hwaddr.sa_data;
        printf("The result of SIOCGIFHWADDR is type %d  "
               "%2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x.\n",
               ifr.ifr_hwaddr.sa_family, hwaddr[0], hwaddr[1],
               hwaddr[2], hwaddr[3], hwaddr[4], hwaddr[5]);

        strcpy(ifr.ifr_name, ifname);
        if (ioctl(skfd, SIOCGIFMETRIC, &ifr) < 0) {
                metric = 0;
        } else
                metric = ifr.ifr_metric;

        strcpy(ifr.ifr_name, ifname);
        if (ioctl(skfd, SIOCGIFMTU, &ifr) < 0)
                mtu = 0;
        else
                mtu = ifr.ifr_mtu;

        strcpy(ifr.ifr_name, ifname);
        if (ioctl(skfd, SIOCGIFDSTADDR, &ifr) < 0) {
                memset(&dstaddr, 0, sizeof(struct sockaddr));
        } else
                dstaddr = ifr.ifr_dstaddr;

        strcpy(ifr.ifr_name, ifname);
        if (ioctl(skfd, SIOCGIFBRDADDR, &ifr) < 0) {
                memset(&broadaddr, 0, sizeof(struct sockaddr));
        } else
                broadaddr = ifr.ifr_broadaddr;

        strcpy(ifr.ifr_name, ifname);
        if (ioctl(skfd, SIOCGIFNETMASK, &ifr) < 0) {
                memset(&netmask, 0, sizeof(struct sockaddr));
        } else
                netmask = ifr.ifr_netmask;

        return 0;
}

static void if_print(char *ifname)
{
        char buff[1024];
        struct ifconf ifc;
        struct ifreq *ifr;
        int i;

        if (ifname == (char *)NULL) {
                ifc.ifc_len = sizeof(buff);
                ifc.ifc_buf = buff;
                if (ioctl(skfd, SIOCGIFCONF, &ifc) < 0) {
                        perror("SIOCGIFCONF failed");
                        return;
                }

                ifr = ifc.ifc_req;
                for (i = ifc.ifc_len / sizeof(struct ifreq); --i >= 0; ifr++) {
                        if (if_getconfig(ifr->ifr_name) < 0) {
                                fprintf(stderr,
                                        "%s: unknown interface.\n",
                                        ifr->ifr_name);
                                continue;
                        }

                        if (((mif_flags & IFF_UP) == 0) && !opt_a) continue;
                        /*ife_print(&ife);*/
                }
        } else {
                if (if_getconfig(ifname) < 0) {
                        fprintf(stderr,
                                "%s: unknown interface.\n", ifname);
                }
        }
}

static int get_drv_info(char *master_ifname)
{
        struct ifreq ifr;
        struct ethtool_drvinfo info;
        char *endptr;

        memset(&ifr, 0, sizeof(ifr));
        strncpy(ifr.ifr_name, master_ifname, IFNAMSIZ);
        ifr.ifr_data = (caddr_t)&info;

        info.cmd = ETHTOOL_GDRVINFO;
        strncpy(info.driver, "ifenslave", 32);
        snprintf(info.fw_version, 32, "%d", BOND_ABI_VERSION);

        if (ioctl(skfd, SIOCETHTOOL, &ifr) < 0) {
                if (errno == EOPNOTSUPP) {
                        goto out;
                }

                saved_errno = errno;
                v_print("Master '%s': Error: get bonding info failed %s\n",
                        master_ifname, strerror(saved_errno));
                return 1;
        }

        abi_ver = strtoul(info.fw_version, &endptr, 0);
        if (*endptr) {
                v_print("Master '%s': Error: got invalid string as an ABI "
                        "version from the bonding module\n",
                        master_ifname);
                return 1;
        }

out:
        v_print("ABI ver is %d\n", abi_ver);

        return 0;
}

static int change_active(char *master_ifname, char *slave_ifname)
{
        struct ifreq ifr;
        int res = 0;

        if (!(slave_flags.ifr_flags & IFF_SLAVE)) {
                fprintf(stderr,
                        "Illegal operation: The specified slave interface "
                        "'%s' is not a slave\n",
                        slave_ifname);
                return 1;
        }

        strncpy(ifr.ifr_name, master_ifname, IFNAMSIZ);
        strncpy(ifr.ifr_slave, slave_ifname, IFNAMSIZ);
        if ((ioctl(skfd, SIOCBONDCHANGEACTIVE, &ifr) < 0) &&
            (ioctl(skfd, BOND_CHANGE_ACTIVE_OLD, &ifr) < 0)) {
                saved_errno = errno;
                v_print("Master '%s': Error: SIOCBONDCHANGEACTIVE failed: "
                        "%s\n",
                        master_ifname, strerror(saved_errno));
                res = 1;
        }

        return res;
}

static int enslave(char *master_ifname, char *slave_ifname)
{
        struct ifreq ifr;
        int res = 0;

        if (slave_flags.ifr_flags & IFF_SLAVE) {
                fprintf(stderr,
                        "Illegal operation: The specified slave interface "
                        "'%s' is already a slave\n",
                        slave_ifname);
                return 1;
        }

        res = set_if_down(slave_ifname, slave_flags.ifr_flags);
        if (res) {
                fprintf(stderr,
                        "Slave '%s': Error: bring interface down failed\n",
                        slave_ifname);
                return res;
        }

        if (abi_ver < 2) {
                /* Older bonding versions would panic if the slave has no IP
                 * address, so get the IP setting from the master.
                 */
                set_if_addr(master_ifname, slave_ifname);
        } else {
                res = clear_if_addr(slave_ifname);
                if (res) {
                        fprintf(stderr,
                                "Slave '%s': Error: clear address failed\n",
                                slave_ifname);
                        return res;
                }
        }

        if (master_mtu.ifr_mtu != slave_mtu.ifr_mtu) {
                res = set_slave_mtu(slave_ifname, master_mtu.ifr_mtu);
                if (res) {
                        fprintf(stderr,
                                "Slave '%s': Error: set MTU failed\n",
                                slave_ifname);
                        return res;
                }
        }

        if (hwaddr_set) {
                /* Master already has an hwaddr
                 * so set it's hwaddr to the slave
                 */
                if (abi_ver < 1) {
                        /* The driver is using an old ABI, so
                         * the application sets the slave's
                         * hwaddr
                         */
                        res = set_slave_hwaddr(slave_ifname,
                                               &(master_hwaddr.ifr_hwaddr));
                        if (res) {
                                fprintf(stderr,
                                        "Slave '%s': Error: set hw address "
                                        "failed\n",
                                        slave_ifname);
                                goto undo_mtu;
                        }

                        /* For old ABI the application needs to bring the
                         * slave back up
                         */
                        res = set_if_up(slave_ifname, slave_flags.ifr_flags);
                        if (res) {
                                fprintf(stderr,
                                        "Slave '%s': Error: bring interface "
                                        "down failed\n",
                                        slave_ifname);
                                goto undo_slave_mac;
                        }
                }
                /* The driver is using a new ABI,
                 * so the driver takes care of setting
                 * the slave's hwaddr and bringing
                 * it up again
                 */
        } else {
                /* No hwaddr for master yet, so
                 * set the slave's hwaddr to it
                 */
                if (abi_ver < 1) {
                        /* For old ABI, the master needs to be
                         * down before setting it's hwaddr
                         */
                        res = set_if_down(master_ifname, master_flags.ifr_flags);
                        if (res) {
                                fprintf(stderr,
                                        "Master '%s': Error: bring interface "
                                        "down failed\n",
                                        master_ifname);
                                goto undo_mtu;
                        }
                }

                res = set_master_hwaddr(master_ifname,
                                        &(slave_hwaddr.ifr_hwaddr));
                if (res) {
                        fprintf(stderr,
                                "Master '%s': Error: set hw address "
                                "failed\n",
                                master_ifname);
                        goto undo_mtu;
                }

                if (abi_ver < 1) {
                        /* For old ABI, bring the master
                         * back up
                         */
                        res = set_if_up(master_ifname, master_flags.ifr_flags);
                        if (res) {
                                fprintf(stderr,
                                        "Master '%s': Error: bring interface "
                                        "up failed\n",
                                        master_ifname);
                                goto undo_master_mac;
                        }
                }

                hwaddr_set = 1;
        }

        /* Do the real thing */
        strncpy(ifr.ifr_name, master_ifname, IFNAMSIZ);
        strncpy(ifr.ifr_slave, slave_ifname, IFNAMSIZ);
        if ((ioctl(skfd, SIOCBONDENSLAVE, &ifr) < 0) &&
            (ioctl(skfd, BOND_ENSLAVE_OLD, &ifr) < 0)) {
                saved_errno = errno;
                v_print("Master '%s': Error: SIOCBONDENSLAVE failed: %s\n",
                        master_ifname, strerror(saved_errno));
                res = 1;
        }

        if (res) {
                goto undo_master_mac;
        }

        return 0;

/* rollback (best effort) */
undo_master_mac:
        set_master_hwaddr(master_ifname, &(master_hwaddr.ifr_hwaddr));
        hwaddr_set = 0;
        goto undo_mtu;
undo_slave_mac:
        set_slave_hwaddr(slave_ifname, &(slave_hwaddr.ifr_hwaddr));
undo_mtu:
        set_slave_mtu(slave_ifname, slave_mtu.ifr_mtu);
        return res;
}

static int release(char *master_ifname, char *slave_ifname)
{
        struct ifreq ifr;
        int res = 0;

        if (!(slave_flags.ifr_flags & IFF_SLAVE)) {
                fprintf(stderr,
                        "Illegal operation: The specified slave interface "
                        "'%s' is not a slave\n",
                        slave_ifname);
                return 1;
        }

        strncpy(ifr.ifr_name, master_ifname, IFNAMSIZ);
        strncpy(ifr.ifr_slave, slave_ifname, IFNAMSIZ);
        if ((ioctl(skfd, SIOCBONDRELEASE, &ifr) < 0) &&
            (ioctl(skfd, BOND_RELEASE_OLD, &ifr) < 0)) {
                saved_errno = errno;
                v_print("Master '%s': Error: SIOCBONDRELEASE failed: %s\n",
                        master_ifname, strerror(saved_errno));
                return 1;
        } else if (abi_ver < 1) {
                /* The driver is using an old ABI, so we'll set the interface
                 * down to avoid any conflicts due to same MAC/IP
                 */
                res = set_if_down(slave_ifname, slave_flags.ifr_flags);
                if (res) {
                        fprintf(stderr,
                                "Slave '%s': Error: bring interface "
                                "down failed\n",
                                slave_ifname);
                }
        }

        /* set to default mtu */
        set_slave_mtu(slave_ifname, 1500);

        return res;
}

static int get_if_settings(char *ifname, struct dev_ifr ifra[])
{
        int i;
        int res = 0;

        for (i = 0; ifra[i].req_ifr; i++) {
                strncpy(ifra[i].req_ifr->ifr_name, ifname, IFNAMSIZ);
                res = ioctl(skfd, ifra[i].req_type, ifra[i].req_ifr);
                if (res < 0) {
                        saved_errno = errno;
                        v_print("Interface '%s': Error: %s failed: %s\n",
                                ifname, ifra[i].req_name,
                                strerror(saved_errno));

                        return saved_errno;
                }
        }

        return 0;
}

static int get_slave_flags(char *slave_ifname)
{
        int res = 0;

        strncpy(slave_flags.ifr_name, slave_ifname, IFNAMSIZ);
        res = ioctl(skfd, SIOCGIFFLAGS, &slave_flags);
        if (res < 0) {
                saved_errno = errno;
                v_print("Slave '%s': Error: SIOCGIFFLAGS failed: %s\n",
                        slave_ifname, strerror(saved_errno));
        } else {
                v_print("Slave %s: flags %04X.\n",
                        slave_ifname, slave_flags.ifr_flags);
        }

        return res;
}

static int set_master_hwaddr(char *master_ifname, struct sockaddr *hwaddr)
{
        unsigned char *addr = (unsigned char *)hwaddr->sa_data;
        struct ifreq ifr;
        int res = 0;

        strncpy(ifr.ifr_name, master_ifname, IFNAMSIZ);
        memcpy(&(ifr.ifr_hwaddr), hwaddr, sizeof(struct sockaddr));
        res = ioctl(skfd, SIOCSIFHWADDR, &ifr);
        if (res < 0) {
                saved_errno = errno;
                v_print("Master '%s': Error: SIOCSIFHWADDR failed: %s\n",
                        master_ifname, strerror(saved_errno));
                return res;
        } else {
                v_print("Master '%s': hardware address set to "
                        "%2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x.\n",
                        master_ifname, addr[0], addr[1], addr[2],
                        addr[3], addr[4], addr[5]);
        }

        return res;
}

static int set_slave_hwaddr(char *slave_ifname, struct sockaddr *hwaddr)
{
        unsigned char *addr = (unsigned char *)hwaddr->sa_data;
        struct ifreq ifr;
        int res = 0;

        strncpy(ifr.ifr_name, slave_ifname, IFNAMSIZ);
        memcpy(&(ifr.ifr_hwaddr), hwaddr, sizeof(struct sockaddr));
        res = ioctl(skfd, SIOCSIFHWADDR, &ifr);
        if (res < 0) {
                saved_errno = errno;

                v_print("Slave '%s': Error: SIOCSIFHWADDR failed: %s\n",
                        slave_ifname, strerror(saved_errno));

                if (saved_errno == EBUSY) {
                        v_print("  The device is busy: it must be idle "
                                "before running this command.\n");
                } else if (saved_errno == EOPNOTSUPP) {
                        v_print("  The device does not support setting "
                                "the MAC address.\n"
                                "  Your kernel likely does not support slave "
                                "devices.\n");
                } else if (saved_errno == EINVAL) {
                        v_print("  The device's address type does not match "
                                "the master's address type.\n");
                }
                return res;
        } else {
                v_print("Slave '%s': hardware address set to "
                        "%2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x.\n",
                        slave_ifname, addr[0], addr[1], addr[2],
                        addr[3], addr[4], addr[5]);
        }

        return res;
}

static int set_slave_mtu(char *slave_ifname, int mtu)
{
        struct ifreq ifr;
        int res = 0;

        ifr.ifr_mtu = mtu;
        strncpy(ifr.ifr_name, slave_ifname, IFNAMSIZ);

        res = ioctl(skfd, SIOCSIFMTU, &ifr);
        if (res < 0) {
                saved_errno = errno;
                v_print("Slave '%s': Error: SIOCSIFMTU failed: %s\n",
                        slave_ifname, strerror(saved_errno));
        } else {
                v_print("Slave '%s': MTU set to %d.\n", slave_ifname, mtu);
        }

        return res;
}

static int set_if_flags(char *ifname, short flags)
{
        struct ifreq ifr;
        int res = 0;

        ifr.ifr_flags = flags;
        strncpy(ifr.ifr_name, ifname, IFNAMSIZ);

        res = ioctl(skfd, SIOCSIFFLAGS, &ifr);
        if (res < 0) {
                saved_errno = errno;
                v_print("Interface '%s': Error: SIOCSIFFLAGS failed: %s\n",
                        ifname, strerror(saved_errno));
        } else {
                v_print("Interface '%s': flags set to %04X.\n", ifname, flags);
        }

        return res;
}

static int set_if_up(char *ifname, short flags)
{
        return set_if_flags(ifname, flags | IFF_UP);
}

static int set_if_down(char *ifname, short flags)
{
        return set_if_flags(ifname, flags & ~IFF_UP);
}

static int clear_if_addr(char *ifname)
{
        struct ifreq ifr;
        int res = 0;

        strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
        ifr.ifr_addr.sa_family = AF_INET;
        memset(ifr.ifr_addr.sa_data, 0, sizeof(ifr.ifr_addr.sa_data));

        res = ioctl(skfd, SIOCSIFADDR, &ifr);
        if (res < 0) {
                saved_errno = errno;
                v_print("Interface '%s': Error: SIOCSIFADDR failed: %s\n",
                        ifname, strerror(saved_errno));
        } else {
                v_print("Interface '%s': address cleared\n", ifname);
        }

        return res;
}

static int set_if_addr(char *master_ifname, char *slave_ifname)
{
        struct ifreq ifr;
        int res;
        unsigned char *ipaddr;
        int i;
        struct {
                char *req_name;
                char *desc;
                int g_ioctl;
                int s_ioctl;
        } ifra[] = {
                {"IFADDR", "addr", SIOCGIFADDR, SIOCSIFADDR},
                {"DSTADDR", "destination addr", SIOCGIFDSTADDR, SIOCSIFDSTADDR},
                {"BRDADDR", "broadcast addr", SIOCGIFBRDADDR, SIOCSIFBRDADDR},
                {"NETMASK", "netmask", SIOCGIFNETMASK, SIOCSIFNETMASK},
                {NULL, NULL, 0, 0},
        };

        for (i = 0; ifra[i].req_name; i++) {
                strncpy(ifr.ifr_name, master_ifname, IFNAMSIZ);
                res = ioctl(skfd, ifra[i].g_ioctl, &ifr);
                if (res < 0) {
                        int saved_errno = errno;

                        v_print("Interface '%s': Error: SIOCG%s failed: %s\n",
                                master_ifname, ifra[i].req_name,
                                strerror(saved_errno));

                        ifr.ifr_addr.sa_family = AF_INET;
                        memset(ifr.ifr_addr.sa_data, 0,
                               sizeof(ifr.ifr_addr.sa_data));
                }

                strncpy(ifr.ifr_name, slave_ifname, IFNAMSIZ);
                res = ioctl(skfd, ifra[i].s_ioctl, &ifr);
                if (res < 0) {
                        int saved_errno = errno;

                        v_print("Interface '%s': Error: SIOCS%s failed: %s\n",
                                slave_ifname, ifra[i].req_name,
                                strerror(saved_errno));

                }

                ipaddr = ifr.ifr_addr.sa_data;
                v_print("Interface '%s': set IP %s to %d.%d.%d.%d\n",
                        slave_ifname, ifra[i].desc,
                        ipaddr[0], ipaddr[1], ipaddr[2], ipaddr[3]);
        }

        return 0;
}

/*
 * Local variables:
 *  version-control: t
 *  kept-new-versions: 5
 *  c-indent-level: 4
 *  c-basic-offset: 4
 *  tab-width: 4
 *  compile-command: "gcc -Wall -Wstrict-prototypes -O -I/usr/src/linux/include ifenslave.c -o ifenslave"
 * End:
 */