busybox/networking/ifconfig.c
James Byrne 6937487be7 libbb: reduce the overhead of single parameter bb_error_msg() calls
Back in 2007, commit 0c97c9d437 ("'simple' error message functions by
Loic Grenie") introduced bb_simple_perror_msg() to allow for a lower
overhead call to bb_perror_msg() when only a string was being printed
with no parameters. This saves space for some CPU architectures because
it avoids the overhead of a call to a variadic function. However there
has never been a simple version of bb_error_msg(), and since 2007 many
new calls to bb_perror_msg() have been added that only take a single
parameter and so could have been using bb_simple_perror_message().

This changeset introduces 'simple' versions of bb_info_msg(),
bb_error_msg(), bb_error_msg_and_die(), bb_herror_msg() and
bb_herror_msg_and_die(), and replaces all calls that only take a
single parameter, or use something like ("%s", arg), with calls to the
corresponding 'simple' version.

Since it is likely that single parameter calls to the variadic functions
may be accidentally reintroduced in the future a new debugging config
option WARN_SIMPLE_MSG has been introduced. This uses some macro magic
which will cause any such calls to generate a warning, but this is
turned off by default to avoid use of the unpleasant macros in normal
circumstances.

This is a large changeset due to the number of calls that have been
replaced. The only files that contain changes other than simple
substitution of function calls are libbb.h, libbb/herror_msg.c,
libbb/verror_msg.c and libbb/xfuncs_printf.c. In miscutils/devfsd.c,
networking/udhcp/common.h and util-linux/mdev.c additonal macros have
been added for logging so that single parameter and multiple parameter
logging variants exist.

The amount of space saved varies considerably by architecture, and was
found to be as follows (for 'defconfig' using GCC 7.4):

Arm:     -92 bytes
MIPS:    -52 bytes
PPC:   -1836 bytes
x86_64: -938 bytes

Note that for the MIPS architecture only an exception had to be made
disabling the 'simple' calls for 'udhcp' (in networking/udhcp/common.h)
because it made these files larger on MIPS.

Signed-off-by: James Byrne <james.byrne@origamienergy.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2019-07-02 11:35:03 +02:00

557 lines
18 KiB
C

/* vi: set sw=4 ts=4: */
/*
* ifconfig
*
* Similar to the standard Unix ifconfig, but with only the necessary
* parts for AF_INET, and without any printing of if info (for now).
*
* Bjorn Wesen, Axis Communications AB
*
* Authors of the original ifconfig was:
* Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
/*
* Heavily modified by Manuel Novoa III Mar 6, 2001
*
* From initial port to busybox, removed most of the redundancy by
* converting to a table-driven approach. Added several (optional)
* args missing from initial port.
*
* Still missing: media, tunnel.
*
* 2002-04-20
* IPV6 support added by Bart Visscher <magick@linux-fan.com>
*/
//config:config IFCONFIG
//config: bool "ifconfig (12 kb)"
//config: default y
//config: select PLATFORM_LINUX
//config: help
//config: Ifconfig is used to configure the kernel-resident network interfaces.
//config:
//config:config FEATURE_IFCONFIG_STATUS
//config: bool "Enable status reporting output (+7k)"
//config: default y
//config: depends on IFCONFIG
//config: help
//config: If ifconfig is called with no arguments it will display the status
//config: of the currently active interfaces.
//config:
//config:config FEATURE_IFCONFIG_SLIP
//config: bool "Enable slip-specific options \"keepalive\" and \"outfill\""
//config: default y
//config: depends on IFCONFIG
//config: help
//config: Allow "keepalive" and "outfill" support for SLIP. If you're not
//config: planning on using serial lines, leave this unchecked.
//config:
//config:config FEATURE_IFCONFIG_MEMSTART_IOADDR_IRQ
//config: bool "Enable options \"mem_start\", \"io_addr\", and \"irq\""
//config: default y
//config: depends on IFCONFIG
//config: help
//config: Allow the start address for shared memory, start address for I/O,
//config: and/or the interrupt line used by the specified device.
//config:
//config:config FEATURE_IFCONFIG_HW
//config: bool "Enable option \"hw\" (ether only)"
//config: default y
//config: depends on IFCONFIG
//config: help
//config: Set the hardware address of this interface, if the device driver
//config: supports this operation. Currently, we only support the 'ether'
//config: class.
//config:
//config:config FEATURE_IFCONFIG_BROADCAST_PLUS
//config: bool "Set the broadcast automatically"
//config: default y
//config: depends on IFCONFIG
//config: help
//config: Setting this will make ifconfig attempt to find the broadcast
//config: automatically if the value '+' is used.
//applet:IF_IFCONFIG(APPLET(ifconfig, BB_DIR_SBIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_IFCONFIG) += ifconfig.o interface.o
//usage:#define ifconfig_trivial_usage
//usage: IF_FEATURE_IFCONFIG_STATUS("[-a]") " interface [address]"
//usage:#define ifconfig_full_usage "\n\n"
//usage: "Configure a network interface\n"
//usage: "\n"
//usage: IF_FEATURE_IPV6(
//usage: " [add ADDRESS[/PREFIXLEN]]\n")
//usage: IF_FEATURE_IPV6(
//usage: " [del ADDRESS[/PREFIXLEN]]\n")
//usage: " [[-]broadcast [ADDRESS]] [[-]pointopoint [ADDRESS]]\n"
//usage: " [netmask ADDRESS] [dstaddr ADDRESS]\n"
//usage: IF_FEATURE_IFCONFIG_SLIP(
//usage: " [outfill NN] [keepalive NN]\n")
//usage: " " IF_FEATURE_IFCONFIG_HW("[hw ether" IF_FEATURE_HWIB("|infiniband")" ADDRESS] ") "[metric NN] [mtu NN]\n"
//usage: " [[-]trailers] [[-]arp] [[-]allmulti]\n"
//usage: " [multicast] [[-]promisc] [txqueuelen NN] [[-]dynamic]\n"
//usage: IF_FEATURE_IFCONFIG_MEMSTART_IOADDR_IRQ(
//usage: " [mem_start NN] [io_addr NN] [irq NN]\n")
//usage: " [up|down] ..."
#include "libbb.h"
#include "inet_common.h"
#include <net/if.h>
#include <net/if_arp.h>
#include <netinet/in.h>
#ifdef HAVE_NET_ETHERNET_H
# include <net/ethernet.h>
#endif
#if ENABLE_FEATURE_IFCONFIG_SLIP
# include <linux/if_slip.h>
#endif
/* I don't know if this is needed for busybox or not. Anyone? */
#define QUESTIONABLE_ALIAS_CASE
/* Defines for glibc2.0 users. */
#ifndef SIOCSIFTXQLEN
# define SIOCSIFTXQLEN 0x8943
# define SIOCGIFTXQLEN 0x8942
#endif
/* ifr_qlen is ifru_ivalue, but it isn't present in 2.0 kernel headers */
#ifndef ifr_qlen
# define ifr_qlen ifr_ifru.ifru_mtu
#endif
#ifndef IFF_DYNAMIC
# define IFF_DYNAMIC 0x8000 /* dialup device with changing addresses */
#endif
#if ENABLE_FEATURE_IPV6
struct in6_ifreq {
struct in6_addr ifr6_addr;
uint32_t ifr6_prefixlen;
int ifr6_ifindex;
};
#endif
/*
* Here are the bit masks for the "flags" member of struct options below.
* N_ signifies no arg prefix; M_ signifies arg prefixed by '-'.
* CLR clears the flag; SET sets the flag; ARG signifies (optional) arg.
*/
#define N_CLR 0x01
#define M_CLR 0x02
#define N_SET 0x04
#define M_SET 0x08
#define N_ARG 0x10
#define M_ARG 0x20
#define M_MASK (M_CLR | M_SET | M_ARG)
#define N_MASK (N_CLR | N_SET | N_ARG)
#define SET_MASK (N_SET | M_SET)
#define CLR_MASK (N_CLR | M_CLR)
#define SET_CLR_MASK (SET_MASK | CLR_MASK)
#define ARG_MASK (M_ARG | N_ARG)
/*
* Here are the bit masks for the "arg_flags" member of struct options below.
*/
/*
* cast type:
* 00 int
* 01 char *
* 02 HOST_COPY in_ether
* 03 HOST_COPY INET_resolve
*/
#define A_CAST_TYPE 0x03
/*
* map type:
* 00 not a map type (mem_start, io_addr, irq)
* 04 memstart (unsigned long)
* 08 io_addr (unsigned short)
* 0C irq (unsigned char)
*/
#define A_MAP_TYPE 0x0C
#define A_ARG_REQ 0x10 /* Set if an arg is required. */
#define A_NETMASK 0x20 /* Set if netmask (check for multiple sets). */
#define A_SET_AFTER 0x40 /* Set a flag at the end. */
#define A_COLON_CHK 0x80 /* Is this needed? See below. */
#if ENABLE_FEATURE_IFCONFIG_BROADCAST_PLUS
#define A_HOSTNAME 0x100 /* Set if it is ip addr. */
#define A_BROADCAST 0x200 /* Set if it is broadcast addr. */
#else
#define A_HOSTNAME 0
#define A_BROADCAST 0
#endif
/*
* These defines are for dealing with the A_CAST_TYPE field.
*/
#define A_CAST_CHAR_PTR 0x01
#define A_CAST_RESOLVE 0x01
#define A_CAST_HOST_COPY 0x02
#define A_CAST_HOST_COPY_IN_ETHER A_CAST_HOST_COPY
#define A_CAST_HOST_COPY_RESOLVE (A_CAST_HOST_COPY | A_CAST_RESOLVE)
/*
* These defines are for dealing with the A_MAP_TYPE field.
*/
#define A_MAP_ULONG 0x04 /* memstart */
#define A_MAP_USHORT 0x08 /* io_addr */
#define A_MAP_UCHAR 0x0C /* irq */
/*
* Define the bit masks signifying which operations to perform for each arg.
*/
#define ARG_METRIC (A_ARG_REQ /*| A_CAST_INT*/)
#define ARG_MTU (A_ARG_REQ /*| A_CAST_INT*/)
#define ARG_TXQUEUELEN (A_ARG_REQ /*| A_CAST_INT*/)
#define ARG_MEM_START (A_ARG_REQ | A_MAP_ULONG)
#define ARG_IO_ADDR (A_ARG_REQ | A_MAP_ULONG)
#define ARG_IRQ (A_ARG_REQ | A_MAP_UCHAR)
#define ARG_DSTADDR (A_ARG_REQ | A_CAST_HOST_COPY_RESOLVE)
#define ARG_NETMASK (A_ARG_REQ | A_CAST_HOST_COPY_RESOLVE | A_NETMASK)
#define ARG_BROADCAST (A_ARG_REQ | A_CAST_HOST_COPY_RESOLVE | A_SET_AFTER | A_BROADCAST)
#define ARG_HW (A_ARG_REQ | A_CAST_HOST_COPY_IN_ETHER)
#define ARG_POINTOPOINT (A_ARG_REQ | A_CAST_HOST_COPY_RESOLVE | A_SET_AFTER)
#define ARG_KEEPALIVE (A_ARG_REQ | A_CAST_CHAR_PTR)
#define ARG_OUTFILL (A_ARG_REQ | A_CAST_CHAR_PTR)
#define ARG_HOSTNAME (A_CAST_HOST_COPY_RESOLVE | A_SET_AFTER | A_COLON_CHK | A_HOSTNAME)
#define ARG_ADD_DEL (A_CAST_HOST_COPY_RESOLVE | A_SET_AFTER)
struct arg1opt {
const char *name;
unsigned short selector;
unsigned short ifr_offset;
};
struct options {
const char *name;
#if ENABLE_FEATURE_IFCONFIG_BROADCAST_PLUS
const unsigned int flags:6;
const unsigned int arg_flags:10;
#else
const unsigned char flags;
const unsigned char arg_flags;
#endif
const unsigned short selector;
};
#define ifreq_offsetof(x) offsetof(struct ifreq, x)
/*
* Set up the tables. Warning! They must have corresponding order!
*/
static const struct arg1opt Arg1Opt[] = {
{ "SIFMETRIC", SIOCSIFMETRIC, ifreq_offsetof(ifr_metric) },
{ "SIFMTU", SIOCSIFMTU, ifreq_offsetof(ifr_mtu) },
{ "SIFTXQLEN", SIOCSIFTXQLEN, ifreq_offsetof(ifr_qlen) },
{ "SIFDSTADDR", SIOCSIFDSTADDR, ifreq_offsetof(ifr_dstaddr) },
{ "SIFNETMASK", SIOCSIFNETMASK, ifreq_offsetof(ifr_netmask) },
{ "SIFBRDADDR", SIOCSIFBRDADDR, ifreq_offsetof(ifr_broadaddr) },
#if ENABLE_FEATURE_IFCONFIG_HW
{ "SIFHWADDR", SIOCSIFHWADDR, ifreq_offsetof(ifr_hwaddr) },
#endif
{ "SIFDSTADDR", SIOCSIFDSTADDR, ifreq_offsetof(ifr_dstaddr) },
#ifdef SIOCSKEEPALIVE
{ "SKEEPALIVE", SIOCSKEEPALIVE, ifreq_offsetof(ifr_data) },
#endif
#ifdef SIOCSOUTFILL
{ "SOUTFILL", SIOCSOUTFILL, ifreq_offsetof(ifr_data) },
#endif
#if ENABLE_FEATURE_IFCONFIG_MEMSTART_IOADDR_IRQ
{ "SIFMAP", SIOCSIFMAP, ifreq_offsetof(ifr_map.mem_start) },
{ "SIFMAP", SIOCSIFMAP, ifreq_offsetof(ifr_map.base_addr) },
{ "SIFMAP", SIOCSIFMAP, ifreq_offsetof(ifr_map.irq) },
#endif
#if ENABLE_FEATURE_IPV6
{ "SIFADDR", SIOCSIFADDR, ifreq_offsetof(ifr_addr) }, /* IPv6 version ignores the offset */
{ "DIFADDR", SIOCDIFADDR, ifreq_offsetof(ifr_addr) }, /* IPv6 version ignores the offset */
#endif
/* Last entry is for unmatched (assumed to be hostname/address) arg. */
{ "SIFADDR", SIOCSIFADDR, ifreq_offsetof(ifr_addr) },
};
static const struct options OptArray[] = {
{ "metric", N_ARG, ARG_METRIC, 0 },
{ "mtu", N_ARG, ARG_MTU, 0 },
{ "txqueuelen", N_ARG, ARG_TXQUEUELEN, 0 },
{ "dstaddr", N_ARG, ARG_DSTADDR, 0 },
{ "netmask", N_ARG, ARG_NETMASK, 0 },
{ "broadcast", N_ARG | M_CLR, ARG_BROADCAST, IFF_BROADCAST },
#if ENABLE_FEATURE_IFCONFIG_HW
{ "hw", N_ARG, ARG_HW, 0 },
#endif
{ "pointopoint", N_ARG | M_CLR, ARG_POINTOPOINT, IFF_POINTOPOINT },
#ifdef SIOCSKEEPALIVE
{ "keepalive", N_ARG, ARG_KEEPALIVE, 0 },
#endif
#ifdef SIOCSOUTFILL
{ "outfill", N_ARG, ARG_OUTFILL, 0 },
#endif
#if ENABLE_FEATURE_IFCONFIG_MEMSTART_IOADDR_IRQ
{ "mem_start", N_ARG, ARG_MEM_START, 0 },
{ "io_addr", N_ARG, ARG_IO_ADDR, 0 },
{ "irq", N_ARG, ARG_IRQ, 0 },
#endif
#if ENABLE_FEATURE_IPV6
{ "add", N_ARG, ARG_ADD_DEL, 0 },
{ "del", N_ARG, ARG_ADD_DEL, 0 },
#endif
{ "arp", N_CLR | M_SET, 0, IFF_NOARP },
{ "trailers", N_CLR | M_SET, 0, IFF_NOTRAILERS },
{ "promisc", N_SET | M_CLR, 0, IFF_PROMISC },
{ "multicast", N_SET | M_CLR, 0, IFF_MULTICAST },
{ "allmulti", N_SET | M_CLR, 0, IFF_ALLMULTI },
{ "dynamic", N_SET | M_CLR, 0, IFF_DYNAMIC },
{ "up", N_SET, 0, (IFF_UP | IFF_RUNNING) },
{ "down", N_CLR, 0, IFF_UP },
{ NULL, 0, ARG_HOSTNAME, (IFF_UP | IFF_RUNNING) }
};
int ifconfig_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int ifconfig_main(int argc UNUSED_PARAM, char **argv)
{
struct ifreq ifr;
struct sockaddr_in sai;
#if ENABLE_FEATURE_IFCONFIG_HW
struct sockaddr sa;
#endif
const struct arg1opt *a1op;
const struct options *op;
int sockfd; /* socket fd we use to manipulate stuff with */
int selector;
#if ENABLE_FEATURE_IFCONFIG_BROADCAST_PLUS
unsigned int mask;
unsigned int did_flags;
unsigned int sai_hostname, sai_netmask;
#else
unsigned char mask;
unsigned char did_flags;
#endif
char *p;
/*char host[128];*/
const char *host = NULL; /* make gcc happy */
IF_FEATURE_IFCONFIG_STATUS(char *show_all_param;)
did_flags = 0;
#if ENABLE_FEATURE_IFCONFIG_BROADCAST_PLUS
sai_hostname = 0;
sai_netmask = 0;
#endif
/* skip argv[0] */
++argv;
#if ENABLE_FEATURE_IFCONFIG_STATUS
show_all_param = NULL;
if (argv[0] && argv[0][0] == '-' && argv[0][1] == 'a' && !argv[0][2]) {
++argv;
show_all_param = IFNAME_SHOW_DOWNED_TOO;
}
#endif
if (!argv[0] || !argv[1]) { /* one or no args */
#if ENABLE_FEATURE_IFCONFIG_STATUS
return display_interfaces(argv[0] ? argv[0] : show_all_param);
#else
bb_simple_error_msg_and_die("no support for status display");
#endif
}
/* Create a channel to the NET kernel. */
sockfd = xsocket(AF_INET, SOCK_DGRAM, 0);
/* get interface name */
strncpy_IFNAMSIZ(ifr.ifr_name, *argv);
/* Process the remaining arguments. */
while (*++argv != NULL) {
p = *argv;
mask = N_MASK;
if (*p == '-') { /* If the arg starts with '-'... */
++p; /* advance past it and */
mask = M_MASK; /* set the appropriate mask. */
}
for (op = OptArray; op->name; op++) { /* Find table entry. */
if (strcmp(p, op->name) == 0) { /* If name matches... */
mask &= op->flags;
if (mask) /* set the mask and go. */
goto FOUND_ARG;
/* If we get here, there was a valid arg with an */
/* invalid '-' prefix. */
bb_error_msg_and_die("bad: '%s'", p-1);
}
}
/* We fell through, so treat as possible hostname. */
a1op = Arg1Opt + ARRAY_SIZE(Arg1Opt) - 1;
mask = op->arg_flags;
goto HOSTNAME;
FOUND_ARG:
if (mask & ARG_MASK) {
mask = op->arg_flags;
if (mask & A_NETMASK & did_flags)
bb_show_usage();
a1op = Arg1Opt + (op - OptArray);
if (*++argv == NULL) {
if (mask & A_ARG_REQ)
bb_show_usage();
--argv;
mask &= A_SET_AFTER; /* just for broadcast */
} else { /* got an arg so process it */
HOSTNAME:
did_flags |= (mask & (A_NETMASK|A_HOSTNAME));
if (mask & A_CAST_HOST_COPY) {
#if ENABLE_FEATURE_IFCONFIG_HW
if (mask & A_CAST_RESOLVE) {
#endif
host = *argv;
if (strcmp(host, "inet") == 0)
continue; /* compat stuff */
sai.sin_family = AF_INET;
sai.sin_port = 0;
if (strcmp(host, "default") == 0) {
/* Default is special, meaning 0.0.0.0. */
sai.sin_addr.s_addr = INADDR_ANY;
}
#if ENABLE_FEATURE_IFCONFIG_BROADCAST_PLUS
else if ((host[0] == '+' && !host[1])
&& (mask & A_BROADCAST)
&& (did_flags & (A_NETMASK|A_HOSTNAME)) == (A_NETMASK|A_HOSTNAME)
) {
/* + is special, meaning broadcast is derived. */
sai.sin_addr.s_addr = (~sai_netmask) | (sai_hostname & sai_netmask);
}
#endif
else {
len_and_sockaddr *lsa;
#if ENABLE_FEATURE_IPV6
char *prefix;
int prefix_len = 0;
prefix = strchr(host, '/');
if (prefix) {
prefix_len = xatou_range(prefix + 1, 0, 128);
*prefix = '\0';
}
resolve:
#endif
lsa = xhost2sockaddr(host, 0);
#if ENABLE_FEATURE_IPV6
if (lsa->u.sa.sa_family != AF_INET6 && prefix) {
/* TODO: we do not support "ifconfig eth0 up 1.2.3.4/17".
* For now, just make it fail instead of silently ignoring "/17" part:
*/
*prefix = '/';
goto resolve;
}
if (lsa->u.sa.sa_family == AF_INET6) {
int sockfd6;
struct in6_ifreq ifr6;
sockfd6 = xsocket(AF_INET6, SOCK_DGRAM, 0);
xioctl(sockfd6, SIOCGIFINDEX, &ifr);
ifr6.ifr6_ifindex = ifr.ifr_ifindex;
ifr6.ifr6_prefixlen = prefix_len;
memcpy(&ifr6.ifr6_addr,
&lsa->u.sin6.sin6_addr,
sizeof(struct in6_addr));
ioctl_or_perror_and_die(sockfd6, a1op->selector, &ifr6, "SIOC%s", a1op->name);
if (ENABLE_FEATURE_CLEAN_UP)
free(lsa);
continue;
}
#endif
sai.sin_addr = lsa->u.sin.sin_addr;
if (ENABLE_FEATURE_CLEAN_UP)
free(lsa);
}
#if ENABLE_FEATURE_IFCONFIG_BROADCAST_PLUS
if (mask & A_HOSTNAME)
sai_hostname = sai.sin_addr.s_addr;
if (mask & A_NETMASK)
sai_netmask = sai.sin_addr.s_addr;
#endif
p = (char *) &sai;
#if ENABLE_FEATURE_IFCONFIG_HW
} else { /* A_CAST_HOST_COPY_IN_ETHER */
/* This is the "hw" arg case. */
smalluint hw_class = index_in_substrings("ether\0"
IF_FEATURE_HWIB("infiniband\0"), *argv) + 1;
if (!hw_class || !*++argv)
bb_show_usage();
host = *argv;
if (hw_class == 1 ? in_ether(host, &sa) : in_ib(host, &sa))
bb_error_msg_and_die("invalid hw-addr %s", host);
p = (char *) &sa;
}
#endif
memcpy( ((char *)&ifr) + a1op->ifr_offset,
p, sizeof(struct sockaddr));
} else {
/* FIXME: error check?? */
unsigned long i = strtoul(*argv, NULL, 0);
p = ((char *)&ifr) + a1op->ifr_offset;
#if ENABLE_FEATURE_IFCONFIG_MEMSTART_IOADDR_IRQ
if (mask & A_MAP_TYPE) {
xioctl(sockfd, SIOCGIFMAP, &ifr);
if ((mask & A_MAP_UCHAR) == A_MAP_UCHAR)
*(unsigned char *) p = i;
else if (mask & A_MAP_USHORT)
*(unsigned short *) p = i;
else
*(unsigned long *) p = i;
} else
#endif
if (mask & A_CAST_CHAR_PTR)
*(caddr_t *) p = (caddr_t) i;
else /* A_CAST_INT */
*(int *) p = i;
}
ioctl_or_perror_and_die(sockfd, a1op->selector, &ifr, "SIOC%s", a1op->name);
#ifdef QUESTIONABLE_ALIAS_CASE
if (mask & A_COLON_CHK) {
/*
* Don't do the set_flag() if the address is an alias with
* a '-' at the end, since it's deleted already! - Roman
*
* Should really use regex.h here, not sure though how well
* it'll go with the cross-platform support etc.
*/
char *ptr;
short int found_colon = 0;
for (ptr = ifr.ifr_name; *ptr; ptr++)
if (*ptr == ':')
found_colon++;
if (found_colon && ptr[-1] == '-')
continue;
}
#endif
}
if (!(mask & A_SET_AFTER))
continue;
mask = N_SET;
} /* if (mask & ARG_MASK) */
xioctl(sockfd, SIOCGIFFLAGS, &ifr);
selector = op->selector;
if (mask & SET_MASK)
ifr.ifr_flags |= selector;
else
ifr.ifr_flags &= ~selector;
xioctl(sockfd, SIOCSIFFLAGS, &ifr);
} /* while () */
if (ENABLE_FEATURE_CLEAN_UP)
close(sockfd);
return 0;
}