networking/ifconfig.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * ifconfig
   4  *
   5  * Similar to the standard Unix ifconfig, but with only the necessary
   6  * parts for AF_INET, and without any printing of if info (for now).
   7  *
   8  * Bjorn Wesen, Axis Communications AB
   9  *
  10  * Authors of the original ifconfig was:
  11  *              Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
  12  *
  13  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  14  */
  15 /*
  16  * Heavily modified by Manuel Novoa III       Mar 6, 2001
  17  *
  18  * From initial port to busybox, removed most of the redundancy by
  19  * converting to a table-driven approach.  Added several (optional)
  20  * args missing from initial port.
  21  *
  22  * Still missing:  media, tunnel.
  23  *
  24  * 2002-04-20
  25  * IPV6 support added by Bart Visscher <magick@linux-fan.com>
  26  */
  27 //config:config IFCONFIG
  28 //config:       bool "ifconfig (12 kb)"
  29 //config:       default y
  30 //config:       select PLATFORM_LINUX
  31 //config:       help
  32 //config:       Ifconfig is used to configure the kernel-resident network interfaces.
  33 //config:
  34 //config:config FEATURE_IFCONFIG_STATUS
  35 //config:       bool "Enable status reporting output (+7k)"
  36 //config:       default y
  37 //config:       depends on IFCONFIG
  38 //config:       help
  39 //config:       If ifconfig is called with no arguments it will display the status
  40 //config:       of the currently active interfaces.
  41 //config:
  42 //config:config FEATURE_IFCONFIG_SLIP
  43 //config:       bool "Enable slip-specific options \"keepalive\" and \"outfill\""
  44 //config:       default y
  45 //config:       depends on IFCONFIG
  46 //config:       help
  47 //config:       Allow "keepalive" and "outfill" support for SLIP. If you're not
  48 //config:       planning on using serial lines, leave this unchecked.
  49 //config:
  50 //config:config FEATURE_IFCONFIG_MEMSTART_IOADDR_IRQ
  51 //config:       bool "Enable options \"mem_start\", \"io_addr\", and \"irq\""
  52 //config:       default y
  53 //config:       depends on IFCONFIG
  54 //config:       help
  55 //config:       Allow the start address for shared memory, start address for I/O,
  56 //config:       and/or the interrupt line used by the specified device.
  57 //config:
  58 //config:config FEATURE_IFCONFIG_HW
  59 //config:       bool "Enable option \"hw\" (ether only)"
  60 //config:       default y
  61 //config:       depends on IFCONFIG
  62 //config:       help
  63 //config:       Set the hardware address of this interface, if the device driver
  64 //config:       supports  this  operation. Currently, we only support the 'ether'
  65 //config:       class.
  66 //config:
  67 //config:config FEATURE_IFCONFIG_BROADCAST_PLUS
  68 //config:       bool "Set the broadcast automatically"
  69 //config:       default y
  70 //config:       depends on IFCONFIG
  71 //config:       help
  72 //config:       Setting this will make ifconfig attempt to find the broadcast
  73 //config:       automatically if the value '+' is used.
  74
  75 //applet:IF_IFCONFIG(APPLET(ifconfig, BB_DIR_SBIN, BB_SUID_DROP))
  76
  77 //kbuild:lib-$(CONFIG_IFCONFIG) += ifconfig.o interface.o
  78
  79 //usage:#define ifconfig_trivial_usage
  80 //usage:        IF_FEATURE_IFCONFIG_STATUS("[-a]") " interface [address]"
  81 //usage:#define ifconfig_full_usage "\n\n"
  82 //usage:       "Configure a network interface\n"
  83 //usage:     "\n"
  84 //usage:        IF_FEATURE_IPV6(
  85 //usage:       "        [add ADDRESS[/PREFIXLEN]]\n")
  86 //usage:        IF_FEATURE_IPV6(
  87 //usage:       "        [del ADDRESS[/PREFIXLEN]]\n")
  88 //usage:       "        [[-]broadcast [ADDRESS]] [[-]pointopoint [ADDRESS]]\n"
  89 //usage:       "        [netmask ADDRESS] [dstaddr ADDRESS]\n"
  90 //usage:        IF_FEATURE_IFCONFIG_SLIP(
  91 //usage:       "        [outfill NN] [keepalive NN]\n")
  92 //usage:       "        " IF_FEATURE_IFCONFIG_HW("[hw ether" IF_FEATURE_HWIB("|infiniband")" ADDRESS] ") "[metric NN] [mtu NN]\n"
  93 //usage:       "        [[-]trailers] [[-]arp] [[-]allmulti]\n"
  94 //usage:       "        [multicast] [[-]promisc] [txqueuelen NN] [[-]dynamic]\n"
  95 //usage:        IF_FEATURE_IFCONFIG_MEMSTART_IOADDR_IRQ(
  96 //usage:       "        [mem_start NN] [io_addr NN] [irq NN]\n")
  97 //usage:       "        [up|down] ..."
  98
  99 #include "libbb.h"
 100 #include "inet_common.h"
 101 #include <net/if.h>
 102 #include <net/if_arp.h>
 103 #include <netinet/in.h>
 104 #ifdef HAVE_NET_ETHERNET_H
 105 # include <net/ethernet.h>
 106 #endif
 107
 108 #if ENABLE_FEATURE_IFCONFIG_SLIP
 109 # include <linux/if_slip.h>
 110 #endif
 111
 112 /* I don't know if this is needed for busybox or not.  Anyone? */
 113 #define QUESTIONABLE_ALIAS_CASE
 114
 115
 116 /* Defines for glibc2.0 users. */
 117 #ifndef SIOCSIFTXQLEN
 118 # define SIOCSIFTXQLEN      0x8943
 119 # define SIOCGIFTXQLEN      0x8942
 120 #endif
 121
 122 /* ifr_qlen is ifru_ivalue, but it isn't present in 2.0 kernel headers */
 123 #ifndef ifr_qlen
 124 # define ifr_qlen        ifr_ifru.ifru_mtu
 125 #endif
 126
 127 #ifndef IFF_DYNAMIC
 128 # define IFF_DYNAMIC     0x8000 /* dialup device with changing addresses */
 129 #endif
 130
 131 #if ENABLE_FEATURE_IPV6
 132 struct in6_ifreq {
 133         struct in6_addr ifr6_addr;
 134         uint32_t ifr6_prefixlen;
 135         int ifr6_ifindex;
 136 };
 137 #endif
 138
 139 /*
 140  * Here are the bit masks for the "flags" member of struct options below.
 141  * N_ signifies no arg prefix; M_ signifies arg prefixed by '-'.
 142  * CLR clears the flag; SET sets the flag; ARG signifies (optional) arg.
 143  */
 144 #define N_CLR            0x01
 145 #define M_CLR            0x02
 146 #define N_SET            0x04
 147 #define M_SET            0x08
 148 #define N_ARG            0x10
 149 #define M_ARG            0x20
 150
 151 #define M_MASK           (M_CLR | M_SET | M_ARG)
 152 #define N_MASK           (N_CLR | N_SET | N_ARG)
 153 #define SET_MASK         (N_SET | M_SET)
 154 #define CLR_MASK         (N_CLR | M_CLR)
 155 #define SET_CLR_MASK     (SET_MASK | CLR_MASK)
 156 #define ARG_MASK         (M_ARG | N_ARG)
 157
 158 /*
 159  * Here are the bit masks for the "arg_flags" member of struct options below.
 160  */
 161
 162 /*
 163  * cast type:
 164  *   00 int
 165  *   01 char *
 166  *   02 HOST_COPY in_ether
 167  *   03 HOST_COPY INET_resolve
 168  */
 169 #define A_CAST_TYPE      0x03
 170 /*
 171  * map type:
 172  *   00 not a map type (mem_start, io_addr, irq)
 173  *   04 memstart (unsigned long)
 174  *   08 io_addr  (unsigned short)
 175  *   0C irq      (unsigned char)
 176  */
 177 #define A_MAP_TYPE       0x0C
 178 #define A_ARG_REQ        0x10   /* Set if an arg is required. */
 179 #define A_NETMASK        0x20   /* Set if netmask (check for multiple sets). */
 180 #define A_SET_AFTER      0x40   /* Set a flag at the end. */
 181 #define A_COLON_CHK      0x80   /* Is this needed?  See below. */
 182 #if ENABLE_FEATURE_IFCONFIG_BROADCAST_PLUS
 183 #define A_HOSTNAME      0x100   /* Set if it is ip addr. */
 184 #define A_BROADCAST     0x200   /* Set if it is broadcast addr. */
 185 #else
 186 #define A_HOSTNAME          0
 187 #define A_BROADCAST         0
 188 #endif
 189
 190 /*
 191  * These defines are for dealing with the A_CAST_TYPE field.
 192  */
 193 #define A_CAST_CHAR_PTR  0x01
 194 #define A_CAST_RESOLVE   0x01
 195 #define A_CAST_HOST_COPY 0x02
 196 #define A_CAST_HOST_COPY_IN_ETHER    A_CAST_HOST_COPY
 197 #define A_CAST_HOST_COPY_RESOLVE     (A_CAST_HOST_COPY | A_CAST_RESOLVE)
 198
 199 /*
 200  * These defines are for dealing with the A_MAP_TYPE field.
 201  */
 202 #define A_MAP_ULONG      0x04   /* memstart */
 203 #define A_MAP_USHORT     0x08   /* io_addr */
 204 #define A_MAP_UCHAR      0x0C   /* irq */
 205
 206 /*
 207  * Define the bit masks signifying which operations to perform for each arg.
 208  */
 209
 210 #define ARG_METRIC       (A_ARG_REQ /*| A_CAST_INT*/)
 211 #define ARG_MTU          (A_ARG_REQ /*| A_CAST_INT*/)
 212 #define ARG_TXQUEUELEN   (A_ARG_REQ /*| A_CAST_INT*/)
 213 #define ARG_MEM_START    (A_ARG_REQ | A_MAP_ULONG)
 214 #define ARG_IO_ADDR      (A_ARG_REQ | A_MAP_ULONG)
 215 #define ARG_IRQ          (A_ARG_REQ | A_MAP_UCHAR)
 216 #define ARG_DSTADDR      (A_ARG_REQ | A_CAST_HOST_COPY_RESOLVE)
 217 #define ARG_NETMASK      (A_ARG_REQ | A_CAST_HOST_COPY_RESOLVE | A_NETMASK)
 218 #define ARG_BROADCAST    (A_ARG_REQ | A_CAST_HOST_COPY_RESOLVE | A_SET_AFTER | A_BROADCAST)
 219 #define ARG_HW           (A_ARG_REQ | A_CAST_HOST_COPY_IN_ETHER)
 220 #define ARG_POINTOPOINT  (A_ARG_REQ | A_CAST_HOST_COPY_RESOLVE | A_SET_AFTER)
 221 #define ARG_KEEPALIVE    (A_ARG_REQ | A_CAST_CHAR_PTR)
 222 #define ARG_OUTFILL      (A_ARG_REQ | A_CAST_CHAR_PTR)
 223 #define ARG_HOSTNAME     (A_CAST_HOST_COPY_RESOLVE | A_SET_AFTER | A_COLON_CHK | A_HOSTNAME)
 224 #define ARG_ADD_DEL      (A_CAST_HOST_COPY_RESOLVE | A_SET_AFTER)
 225
 226
 227 struct arg1opt {
 228         const char *name;
 229         unsigned short selector;
 230         unsigned short ifr_offset;
 231 };
 232
 233 struct options {
 234         const char *name;
 235 #if ENABLE_FEATURE_IFCONFIG_BROADCAST_PLUS
 236         const unsigned int flags:6;
 237         const unsigned int arg_flags:10;
 238 #else
 239         const unsigned char flags;
 240         const unsigned char arg_flags;
 241 #endif
 242         const unsigned short selector;
 243 };
 244
 245 #define ifreq_offsetof(x)  offsetof(struct ifreq, x)
 246
 247 /*
 248  * Set up the tables.  Warning!  They must have corresponding order!
 249  */
 250
 251 static const struct arg1opt Arg1Opt[] = {
 252         { "SIFMETRIC",  SIOCSIFMETRIC,  ifreq_offsetof(ifr_metric) },
 253         { "SIFMTU",     SIOCSIFMTU,     ifreq_offsetof(ifr_mtu) },
 254         { "SIFTXQLEN",  SIOCSIFTXQLEN,  ifreq_offsetof(ifr_qlen) },
 255         { "SIFDSTADDR", SIOCSIFDSTADDR, ifreq_offsetof(ifr_dstaddr) },
 256         { "SIFNETMASK", SIOCSIFNETMASK, ifreq_offsetof(ifr_netmask) },
 257         { "SIFBRDADDR", SIOCSIFBRDADDR, ifreq_offsetof(ifr_broadaddr) },
 258 #if ENABLE_FEATURE_IFCONFIG_HW
 259         { "SIFHWADDR",  SIOCSIFHWADDR,  ifreq_offsetof(ifr_hwaddr) },
 260 #endif
 261         { "SIFDSTADDR", SIOCSIFDSTADDR, ifreq_offsetof(ifr_dstaddr) },
 262 #ifdef SIOCSKEEPALIVE
 263         { "SKEEPALIVE", SIOCSKEEPALIVE, ifreq_offsetof(ifr_data) },
 264 #endif
 265 #ifdef SIOCSOUTFILL
 266         { "SOUTFILL",   SIOCSOUTFILL,   ifreq_offsetof(ifr_data) },
 267 #endif
 268 #if ENABLE_FEATURE_IFCONFIG_MEMSTART_IOADDR_IRQ
 269         { "SIFMAP",     SIOCSIFMAP,     ifreq_offsetof(ifr_map.mem_start) },
 270         { "SIFMAP",     SIOCSIFMAP,     ifreq_offsetof(ifr_map.base_addr) },
 271         { "SIFMAP",     SIOCSIFMAP,     ifreq_offsetof(ifr_map.irq) },
 272 #endif
 273 #if ENABLE_FEATURE_IPV6
 274         { "SIFADDR",    SIOCSIFADDR,    ifreq_offsetof(ifr_addr) }, /* IPv6 version ignores the offset */
 275         { "DIFADDR",    SIOCDIFADDR,    ifreq_offsetof(ifr_addr) }, /* IPv6 version ignores the offset */
 276 #endif
 277         /* Last entry is for unmatched (assumed to be hostname/address) arg. */
 278         { "SIFADDR",    SIOCSIFADDR,    ifreq_offsetof(ifr_addr) },
 279 };
 280
 281 static const struct options OptArray[] = {
 282         { "metric",      N_ARG,         ARG_METRIC,      0 },
 283         { "mtu",         N_ARG,         ARG_MTU,         0 },
 284         { "txqueuelen",  N_ARG,         ARG_TXQUEUELEN,  0 },
 285         { "dstaddr",     N_ARG,         ARG_DSTADDR,     0 },
 286         { "netmask",     N_ARG,         ARG_NETMASK,     0 },
 287         { "broadcast",   N_ARG | M_CLR, ARG_BROADCAST,   IFF_BROADCAST },
 288 #if ENABLE_FEATURE_IFCONFIG_HW
 289         { "hw",          N_ARG,         ARG_HW,          0 },
 290 #endif
 291         { "pointopoint", N_ARG | M_CLR, ARG_POINTOPOINT, IFF_POINTOPOINT },
 292 #ifdef SIOCSKEEPALIVE
 293         { "keepalive",   N_ARG,         ARG_KEEPALIVE,   0 },
 294 #endif
 295 #ifdef SIOCSOUTFILL
 296         { "outfill",     N_ARG,         ARG_OUTFILL,     0 },
 297 #endif
 298 #if ENABLE_FEATURE_IFCONFIG_MEMSTART_IOADDR_IRQ
 299         { "mem_start",   N_ARG,         ARG_MEM_START,   0 },
 300         { "io_addr",     N_ARG,         ARG_IO_ADDR,     0 },
 301         { "irq",         N_ARG,         ARG_IRQ,         0 },
 302 #endif
 303 #if ENABLE_FEATURE_IPV6
 304         { "add",         N_ARG,         ARG_ADD_DEL,     0 },
 305         { "del",         N_ARG,         ARG_ADD_DEL,     0 },
 306 #endif
 307         { "arp",         N_CLR | M_SET, 0,               IFF_NOARP },
 308         { "trailers",    N_CLR | M_SET, 0,               IFF_NOTRAILERS },
 309         { "promisc",     N_SET | M_CLR, 0,               IFF_PROMISC },
 310         { "multicast",   N_SET | M_CLR, 0,               IFF_MULTICAST },
 311         { "allmulti",    N_SET | M_CLR, 0,               IFF_ALLMULTI },
 312         { "dynamic",     N_SET | M_CLR, 0,               IFF_DYNAMIC },
 313         { "up",          N_SET,         0,               (IFF_UP | IFF_RUNNING) },
 314         { "down",        N_CLR,         0,               IFF_UP },
 315         { NULL,          0,             ARG_HOSTNAME,    (IFF_UP | IFF_RUNNING) }
 316 };
 317
 318 int ifconfig_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 319 int ifconfig_main(int argc UNUSED_PARAM, char **argv)
 320 {
 321         struct ifreq ifr;
 322         struct sockaddr_in sai;
 323 #if ENABLE_FEATURE_IFCONFIG_HW
 324         struct sockaddr sa;
 325 #endif
 326         const struct arg1opt *a1op;
 327         const struct options *op;
 328         int sockfd;                     /* socket fd we use to manipulate stuff with */
 329         int selector;
 330 #if ENABLE_FEATURE_IFCONFIG_BROADCAST_PLUS
 331         unsigned int mask;
 332         unsigned int did_flags;
 333         unsigned int sai_hostname, sai_netmask;
 334 #else
 335         unsigned char mask;
 336         unsigned char did_flags;
 337 #endif
 338         char *p;
 339         /*char host[128];*/
 340         const char *host = NULL; /* make gcc happy */
 341         IF_FEATURE_IFCONFIG_STATUS(char *show_all_param;)
 342
 343         did_flags = 0;
 344 #if ENABLE_FEATURE_IFCONFIG_BROADCAST_PLUS
 345         sai_hostname = 0;
 346         sai_netmask = 0;
 347 #endif
 348
 349         /* skip argv[0] */
 350         ++argv;
 351
 352 #if ENABLE_FEATURE_IFCONFIG_STATUS
 353         show_all_param = NULL;
 354         if (argv[0] && argv[0][0] == '-' && argv[0][1] == 'a' && !argv[0][2]) {
 355                 ++argv;
 356                 show_all_param = IFNAME_SHOW_DOWNED_TOO;
 357         }
 358 #endif
 359
 360         if (!argv[0] || !argv[1]) { /* one or no args */
 361 #if ENABLE_FEATURE_IFCONFIG_STATUS
 362                 return display_interfaces(argv[0] ? argv[0] : show_all_param);
 363 #else
 364                 bb_error_msg_and_die("no support for status display");
 365 #endif
 366         }
 367
 368         /* Create a channel to the NET kernel. */
 369         sockfd = xsocket(AF_INET, SOCK_DGRAM, 0);
 370
 371         /* get interface name */
 372         strncpy_IFNAMSIZ(ifr.ifr_name, *argv);
 373
 374         /* Process the remaining arguments. */
 375         while (*++argv != NULL) {
 376                 p = *argv;
 377                 mask = N_MASK;
 378                 if (*p == '-') {        /* If the arg starts with '-'... */
 379                         ++p;            /*    advance past it and */
 380                         mask = M_MASK;  /*    set the appropriate mask. */
 381                 }
 382                 for (op = OptArray; op->name; op++) {   /* Find table entry. */
 383                         if (strcmp(p, op->name) == 0) { /* If name matches... */
 384                                 mask &= op->flags;
 385                                 if (mask)       /* set the mask and go. */
 386                                         goto FOUND_ARG;
 387                                 /* If we get here, there was a valid arg with an */
 388                                 /* invalid '-' prefix. */
 389                                 bb_error_msg_and_die("bad: '%s'", p-1);
 390                         }
 391                 }
 392
 393                 /* We fell through, so treat as possible hostname. */
 394                 a1op = Arg1Opt + ARRAY_SIZE(Arg1Opt) - 1;
 395                 mask = op->arg_flags;
 396                 goto HOSTNAME;
 397
 398  FOUND_ARG:
 399                 if (mask & ARG_MASK) {
 400                         mask = op->arg_flags;
 401                         if (mask & A_NETMASK & did_flags)
 402                                 bb_show_usage();
 403                         a1op = Arg1Opt + (op - OptArray);
 404                         if (*++argv == NULL) {
 405                                 if (mask & A_ARG_REQ)
 406                                         bb_show_usage();
 407                                 --argv;
 408                                 mask &= A_SET_AFTER;    /* just for broadcast */
 409                         } else {        /* got an arg so process it */
 410  HOSTNAME:
 411                                 did_flags |= (mask & (A_NETMASK|A_HOSTNAME));
 412                                 if (mask & A_CAST_HOST_COPY) {
 413 #if ENABLE_FEATURE_IFCONFIG_HW
 414                                         if (mask & A_CAST_RESOLVE) {
 415 #endif
 416                                                 host = *argv;
 417                                                 if (strcmp(host, "inet") == 0)
 418                                                         continue; /* compat stuff */
 419                                                 sai.sin_family = AF_INET;
 420                                                 sai.sin_port = 0;
 421                                                 if (strcmp(host, "default") == 0) {
 422                                                         /* Default is special, meaning 0.0.0.0. */
 423                                                         sai.sin_addr.s_addr = INADDR_ANY;
 424                                                 }
 425 #if ENABLE_FEATURE_IFCONFIG_BROADCAST_PLUS
 426                                                 else if ((host[0] == '+' && !host[1])
 427                                                  && (mask & A_BROADCAST)
 428                                                  && (did_flags & (A_NETMASK|A_HOSTNAME)) == (A_NETMASK|A_HOSTNAME)
 429                                                 ) {
 430                                                         /* + is special, meaning broadcast is derived. */
 431                                                         sai.sin_addr.s_addr = (~sai_netmask) | (sai_hostname & sai_netmask);
 432                                                 }
 433 #endif
 434                                                 else {
 435                                                         len_and_sockaddr *lsa;
 436 #if ENABLE_FEATURE_IPV6
 437                                                         char *prefix;
 438                                                         int prefix_len = 0;
 439                                                         prefix = strchr(host, '/');
 440                                                         if (prefix) {
 441                                                                 prefix_len = xatou_range(prefix + 1, 0, 128);
 442                                                                 *prefix = '\0';
 443                                                         }
 444  resolve:
 445 #endif
 446                                                         lsa = xhost2sockaddr(host, 0);
 447 #if ENABLE_FEATURE_IPV6
 448                                                         if (lsa->u.sa.sa_family != AF_INET6 && prefix) {
 449 /* TODO: we do not support "ifconfig eth0 up 1.2.3.4/17".
 450  * For now, just make it fail instead of silently ignoring "/17" part:
 451  */
 452                                                                 *prefix = '/';
 453                                                                 goto resolve;
 454                                                         }
 455                                                         if (lsa->u.sa.sa_family == AF_INET6) {
 456                                                                 int sockfd6;
 457                                                                 struct in6_ifreq ifr6;
 458
 459                                                                 sockfd6 = xsocket(AF_INET6, SOCK_DGRAM, 0);
 460                                                                 xioctl(sockfd6, SIOCGIFINDEX, &ifr);
 461                                                                 ifr6.ifr6_ifindex = ifr.ifr_ifindex;
 462                                                                 ifr6.ifr6_prefixlen = prefix_len;
 463                                                                 memcpy(&ifr6.ifr6_addr,
 464                                                                                 &lsa->u.sin6.sin6_addr,
 465                                                                                 sizeof(struct in6_addr));
 466                                                                 ioctl_or_perror_and_die(sockfd6, a1op->selector, &ifr6, "SIOC%s", a1op->name);
 467                                                                 if (ENABLE_FEATURE_CLEAN_UP)
 468                                                                         free(lsa);
 469                                                                 continue;
 470                                                         }
 471 #endif
 472                                                         sai.sin_addr = lsa->u.sin.sin_addr;
 473                                                         if (ENABLE_FEATURE_CLEAN_UP)
 474                                                                 free(lsa);
 475                                                 }
 476 #if ENABLE_FEATURE_IFCONFIG_BROADCAST_PLUS
 477                                                 if (mask & A_HOSTNAME)
 478                                                         sai_hostname = sai.sin_addr.s_addr;
 479                                                 if (mask & A_NETMASK)
 480                                                         sai_netmask = sai.sin_addr.s_addr;
 481 #endif
 482                                                 p = (char *) &sai;
 483 #if ENABLE_FEATURE_IFCONFIG_HW
 484                                         } else {        /* A_CAST_HOST_COPY_IN_ETHER */
 485                                                 /* This is the "hw" arg case. */
 486                                                 smalluint hw_class = index_in_substrings("ether\0"
 487                                                                 IF_FEATURE_HWIB("infiniband\0"), *argv) + 1;
 488                                                 if (!hw_class || !*++argv)
 489                                                         bb_show_usage();
 490                                                 host = *argv;
 491                                                 if (hw_class == 1 ? in_ether(host, &sa) : in_ib(host, &sa))
 492                                                         bb_error_msg_and_die("invalid hw-addr %s", host);
 493                                                 p = (char *) &sa;
 494                                         }
 495 #endif
 496                                         memcpy( ((char *)&ifr) + a1op->ifr_offset,
 497                                                 p, sizeof(struct sockaddr));
 498                                 } else {
 499                                         /* FIXME: error check?? */
 500                                         unsigned long i = strtoul(*argv, NULL, 0);
 501                                         p = ((char *)&ifr) + a1op->ifr_offset;
 502 #if ENABLE_FEATURE_IFCONFIG_MEMSTART_IOADDR_IRQ
 503                                         if (mask & A_MAP_TYPE) {
 504                                                 xioctl(sockfd, SIOCGIFMAP, &ifr);
 505                                                 if ((mask & A_MAP_UCHAR) == A_MAP_UCHAR)
 506                                                         *(unsigned char *) p = i;
 507                                                 else if (mask & A_MAP_USHORT)
 508                                                         *(unsigned short *) p = i;
 509                                                 else
 510                                                         *(unsigned long *) p = i;
 511                                         } else
 512 #endif
 513                                         if (mask & A_CAST_CHAR_PTR)
 514                                                 *(caddr_t *) p = (caddr_t) i;
 515                                         else    /* A_CAST_INT */
 516                                                 *(int *) p = i;
 517                                 }
 518
 519                                 ioctl_or_perror_and_die(sockfd, a1op->selector, &ifr, "SIOC%s", a1op->name);
 520 #ifdef QUESTIONABLE_ALIAS_CASE
 521                                 if (mask & A_COLON_CHK) {
 522                                         /*
 523                                          * Don't do the set_flag() if the address is an alias with
 524                                          * a '-' at the end, since it's deleted already! - Roman
 525                                          *
 526                                          * Should really use regex.h here, not sure though how well
 527                                          * it'll go with the cross-platform support etc.
 528                                          */
 529                                         char *ptr;
 530                                         short int found_colon = 0;
 531                                         for (ptr = ifr.ifr_name; *ptr; ptr++)
 532                                                 if (*ptr == ':')
 533                                                         found_colon++;
 534                                         if (found_colon && ptr[-1] == '-')
 535                                                 continue;
 536                                 }
 537 #endif
 538                         }
 539                         if (!(mask & A_SET_AFTER))
 540                                 continue;
 541                         mask = N_SET;
 542                 } /* if (mask & ARG_MASK) */
 543
 544                 xioctl(sockfd, SIOCGIFFLAGS, &ifr);
 545                 selector = op->selector;
 546                 if (mask & SET_MASK)
 547                         ifr.ifr_flags |= selector;
 548                 else
 549                         ifr.ifr_flags &= ~selector;
 550                 xioctl(sockfd, SIOCSIFFLAGS, &ifr);
 551         } /* while () */
 552
 553         if (ENABLE_FEATURE_CLEAN_UP)
 554                 close(sockfd);
 555         return 0;
 556 }