udhcpc: allow zero server-id. Closes 6614.
[oweals/busybox.git] / networking / ifconfig.c
index f342ceedefa54033d27789b210971dea6ece0d10..8984b020773f082792931fdc3466f26c3874c539 100644 (file)
@@ -1,3 +1,4 @@
+/* vi: set sw=4 ts=4: */
 /* ifconfig
  *
  * Similar to the standard Unix ifconfig, but with only the necessary
@@ -6,17 +7,10 @@
  * Bjorn Wesen, Axis Communications AB
  *
  *
- * Authors of the original ifconfig was:      
+ * Authors of the original ifconfig was:
  *              Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
  *
- * 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;  either  version 2 of the License, or  (at
- * your option) any later version.
- *
- * $Id: ifconfig.c,v 1.5 2001/03/08 22:57:00 mjn3 Exp $
- *
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 
 /*
  * converting to a table-driven approach.  Added several (optional)
  * args missing from initial port.
  *
- * Still missing:  media.
+ * Still missing:  media, tunnel.
+ *
+ * 2002-04-20
+ * IPV6 support added by Bart Visscher <magick@linux-fan.com>
  */
 
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>   // strcmp and friends
-#include <ctype.h>    // isdigit and friends
-#include <stddef.h>                            /* offsetof */
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <sys/ioctl.h>
-#include <netinet/in.h>
-#include <arpa/inet.h>
+//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 <linux/if_ether.h>
-#include "busybox.h"
+#include <netinet/in.h>
+#ifdef HAVE_NET_ETHERNET_H
+# include <net/ethernet.h>
+#endif
 
-#ifdef BB_FEATURE_IFCONFIG_SLIP
-#include <linux/if_slip.h>
+#if ENABLE_FEATURE_IFCONFIG_SLIP
+# include <linux/if_slip.h>
 #endif
 
 /* I don't know if this is needed for busybox or not.  Anyone? */
 
 /* Defines for glibc2.0 users. */
 #ifndef SIOCSIFTXQLEN
-#define SIOCSIFTXQLEN      0x8943
-#define SIOCGIFTXQLEN      0x8942
+# 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
+# define ifr_qlen        ifr_ifru.ifru_mtu
 #endif
 
 #ifndef IFF_DYNAMIC
-#define IFF_DYNAMIC     0x8000  /* dialup device with changing addresses */
+# 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
 
 /*
 #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 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_USHORT)
+#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)
+#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_CAST_HOST_COPY_RESOLVE | A_SET_AFTER)
+#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)
+#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)
 
 
-/*
- * Set up the tables.  Warning!  They must have corresponding order!
- */
-
 struct arg1opt {
        const char *name;
        unsigned short selector;
@@ -159,326 +182,323 @@ struct arg1opt {
 
 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[] = {
-       {"SIOCSIFMETRIC",  SIOCSIFMETRIC,  ifreq_offsetof(ifr_metric)},
-       {"SIOCSIFMTU",     SIOCSIFMTU,     ifreq_offsetof(ifr_mtu)},
-       {"SIOCSIFTXQLEN",  SIOCSIFTXQLEN,  ifreq_offsetof(ifr_qlen)},
-       {"SIOCSIFDSTADDR", SIOCSIFDSTADDR, ifreq_offsetof(ifr_dstaddr)},
-       {"SIOCSIFNETMASK", SIOCSIFNETMASK, ifreq_offsetof(ifr_netmask)},
-       {"SIOCSIFBRDADDR", SIOCSIFBRDADDR, ifreq_offsetof(ifr_broadaddr)},
-#ifdef BB_FEATURE_IFCONFIG_HW
-       {"SIOCSIFHWADDR",  SIOCSIFHWADDR,  ifreq_offsetof(ifr_hwaddr)},
+       { "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
-       {"SIOCSIFDSTADDR", SIOCSIFDSTADDR, ifreq_offsetof(ifr_dstaddr)},
+       { "SIFDSTADDR", SIOCSIFDSTADDR, ifreq_offsetof(ifr_dstaddr) },
 #ifdef SIOCSKEEPALIVE
-       {"SIOCSKEEPALIVE", SIOCSKEEPALIVE, ifreq_offsetof(ifr_data)},
+       { "SKEEPALIVE", SIOCSKEEPALIVE, ifreq_offsetof(ifr_data) },
 #endif
 #ifdef SIOCSOUTFILL
-       {"SIOCSOUTFILL",   SIOCSOUTFILL,   ifreq_offsetof(ifr_data)},
+       { "SOUTFILL",   SIOCSOUTFILL,   ifreq_offsetof(ifr_data) },
 #endif
-#ifdef BB_FEATURE_IFCONFIG_MEMSTART_IOADDR_IRQ
-       {"SIOCSIFMAP",     SIOCSIFMAP,     ifreq_offsetof(ifr_map.mem_start)},
-       {"SIOCSIFMAP",     SIOCSIFMAP,     ifreq_offsetof(ifr_map.base_addr)},
-       {"SIOCSIFMAP",     SIOCSIFMAP,     ifreq_offsetof(ifr_map.irq)},
+#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
-       /* Last entry if for unmatched (possibly hostname) arg. */
-       {"SIOCSIFADDR",    SIOCSIFADDR,    ifreq_offsetof(ifr_addr)},
+#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},
-#ifdef BB_FEATURE_IFCONFIG_HW
-       {"hw",           N_ARG,         ARG_HW,          0},
+       { "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},
+       { "pointopoint", N_ARG | M_CLR, ARG_POINTOPOINT, IFF_POINTOPOINT },
 #ifdef SIOCSKEEPALIVE
-       {"keepalive",    N_ARG,         ARG_KEEPALIVE,   0},
+       { "keepalive",   N_ARG,         ARG_KEEPALIVE,   0 },
 #endif
 #ifdef SIOCSOUTFILL
-       {"outfill",      N_ARG,         ARG_OUTFILL,     0},
+       { "outfill",     N_ARG,         ARG_OUTFILL,     0 },
 #endif
-#ifdef BB_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},
+#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
-       {"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)}
-};
-
-/*
- * A couple of prototypes.
- */
-
-#ifdef BB_FEATURE_IFCONFIG_HW
-static int in_ether(char *bufp, struct sockaddr *sap);
+#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) }
+};
 
-#ifdef BB_FEATURE_IFCONFIG_STATUS
-extern int display_interfaces(void);
-#endif
-
-/*
- * Our main function.
- */
-
-int ifconfig_main(int argc, char **argv)
+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;
-#ifdef BB_FEATURE_IFCONFIG_HW
+#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 goterr;
+       int sockfd;                     /* socket fd we use to manipulate stuff with */
        int selector;
-       char *p;
-       char host[128];
+#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 */
 
-       goterr = 0;
        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
+       if (argv[0] && (argv[0][0] == '-' && argv[0][1] == 'a' && !argv[0][2])) {
+               interface_opt_a = 1;
+               ++argv;
+       }
+#endif
 
-       if(argc < 2) {
-#ifdef BB_FEATURE_IFCONFIG_STATUS
-               return(display_interfaces());
+       if (!argv[0] || !argv[1]) { /* one or no args */
+#if ENABLE_FEATURE_IFCONFIG_STATUS
+               return display_interfaces(argv[0] /* can be NULL */);
 #else
-               show_usage();
+               bb_error_msg_and_die("no support for status display");
 #endif
        }
 
        /* Create a channel to the NET kernel. */
-       if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
-               perror("socket");
-               exit(1);
-       }
-
-       /* skip argv[0] */
-       argc--;
-       argv++;
+       sockfd = xsocket(AF_INET, SOCK_DGRAM, 0);
 
        /* get interface name */
-       safe_strncpy(ifr.ifr_name, *argv, IFNAMSIZ);
+       strncpy_IFNAMSIZ(ifr.ifr_name, *argv);
 
        /* Process the remaining arguments. */
-       while (*++argv != (char *) NULL) {
+       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. */
+               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)) { /* If name matches... */
-                               if ((mask &= op->flags)) { /* set the mask and go. */
-                                   goto FOUND_ARG;;
-                               }
+               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. */
-                               ++goterr;
-                               goto LOOP;
+                               bb_error_msg_and_die("bad: '%s'", p-1);
                        }
                }
-               
+
                /* We fell through, so treat as possible hostname. */
-               a1op = Arg1Opt + (sizeof(Arg1Opt) / sizeof(Arg1Opt[0])) - 1;
+               a1op = Arg1Opt + ARRAY_SIZE(Arg1Opt) - 1;
                mask = op->arg_flags;
                goto HOSTNAME;
 
      FOUND_ARG:
+ FOUND_ARG:
                if (mask & ARG_MASK) {
                        mask = op->arg_flags;
+                       if (mask & A_NETMASK & did_flags)
+                               bb_show_usage();
                        a1op = Arg1Opt + (op - OptArray);
-                       if (mask & A_NETMASK & did_flags) {
-                               show_usage();
-                       }
                        if (*++argv == NULL) {
-                               if (mask & A_ARG_REQ) {
-                                       show_usage();
-                               } else {
-                                       --argv;
-                                       mask &= A_SET_AFTER; /* just for broadcast */
-                               }
-                       } else {                        /* got an arg so process it */
-                       HOSTNAME:
-                               did_flags |= (mask & A_NETMASK);
+                               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) {
-#ifdef BB_FEATURE_IFCONFIG_HW
+#if ENABLE_FEATURE_IFCONFIG_HW
                                        if (mask & A_CAST_RESOLVE) {
 #endif
-                                               safe_strncpy(host, *argv, (sizeof host));
+                                               host = *argv;
+                                               if (strcmp(host, "inet") == 0)
+                                                       continue; /* compat stuff */
                                                sai.sin_family = AF_INET;
                                                sai.sin_port = 0;
-                                               if (!strcmp(host, "default")) {
+                                               if (strcmp(host, "default") == 0) {
                                                        /* Default is special, meaning 0.0.0.0. */
                                                        sai.sin_addr.s_addr = INADDR_ANY;
-                                               } else if (inet_aton(host, &sai.sin_addr) == 0) {
-                                                       /* It's not a dotted quad. */
-                                                       ++goterr;
-                                                       continue;
                                                }
-                                               p = (char *) &sai;
-#ifdef BB_FEATURE_IFCONFIG_HW
-                                       } else { /* A_CAST_HOST_COPY_IN_ETHER */
-                                               /* This is the "hw" arg case. */
-                                               if (strcmp("ether", *argv) || (*++argv == NULL)) {
-                                                       show_usage();
+#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);
                                                }
-                                               safe_strncpy(host, *argv, (sizeof host));
-                                               if (in_ether(host, &sa)) {
-                                                       fprintf(stderr, "invalid hw-addr %s\n", host);
-                                                       ++goterr;
-                                                       continue;
+#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));
+                                       memcpy( ((char *)&ifr) + a1op->ifr_offset,
+                                               p, sizeof(struct sockaddr));
                                } else {
-                                       unsigned int i = strtoul(*argv,NULL,0);
-                                       p = ((char *)(&ifr)) + a1op->ifr_offset;
-#ifdef BB_FEATURE_IFCONFIG_MEMSTART_IOADDR_IRQ
+                                       /* 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) {
-                                               if (ioctl(sockfd, SIOCGIFMAP, &ifr) < 0) {
-                                                       ++goterr;
-                                                       continue;
-                                               }
-                                               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;
-                                               }
+                                               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;
-                                       }
-                               }
-                                               
-                               if (ioctl(sockfd, a1op->selector, &ifr) < 0) {
-                                       perror(a1op->name);
-                                       ++goterr;
-                                       continue;
+                                       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
+                                        * 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. 
+                                        * 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 == ':') {
+                                       for (ptr = ifr.ifr_name; *ptr; ptr++)
+                                               if (*ptr == ':')
                                                        found_colon++;
-                                               }
-                                       }
-                       
-                                       if (found_colon && *(ptr - 1) == '-') {
+                                       if (found_colon && ptr[-1] == '-')
                                                continue;
-                                       }
                                }
 #endif
                        }
-                       if (!(mask & A_SET_AFTER)) {
+                       if (!(mask & A_SET_AFTER))
                                continue;
-                       }
                        mask = N_SET;
-               }
-
-               if (ioctl(sockfd, SIOCGIFFLAGS, &ifr) < 0) {
-                       perror("SIOCGIFFLAGS"); 
-                       ++goterr;
-               } else {
-                       selector = op->selector;
-                       if (mask & SET_MASK) {
-                               ifr.ifr_flags |= selector;
-                       } else {
-                               ifr.ifr_flags &= ~selector;
-                       }
-                       if (ioctl(sockfd, SIOCSIFFLAGS, &ifr) < 0) {
-                               perror("SIOCSIFFLAGS"); 
-                               ++goterr;
-                       }
-               }
-       LOOP:
-       } /* end of while-loop */
-
-       return goterr;
+               } /* 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;
 }
-
-#ifdef BB_FEATURE_IFCONFIG_HW
-/* Input an Ethernet address and convert to binary. */
-static int
-in_ether(char *bufp, struct sockaddr *sap)
-{
-       unsigned char *ptr;
-       int i, j;
-       unsigned char val;
-       unsigned char c;
-       
-       sap->sa_family = ARPHRD_ETHER;
-       ptr = sap->sa_data;
-       
-       for (i = 0 ; i < ETH_ALEN ; i++) {
-               val = 0;
-
-               /* We might get a semicolon here - not required. */
-               if (i && (*bufp == ':')) {
-                       bufp++;
-               }
-
-               for (j=0 ; j<2 ; j++) {
-                       c = *bufp;
-                       if (c >= '0' && c <= '9') {
-                               c -= '0';
-                       } else if (c >= 'a' && c <= 'f') {
-                               c -= ('a' + 10);
-                       } else if (c >= 'A' && c <= 'F') {
-                               c -= ('A' + 10);
-                       } else if (j && (c == ':' || c == 0)) {
-                               break;
-                       } else {
-                               return -1;
-                       }
-                       ++bufp;
-                       val <<= 4;
-                       val += c;
-               }
-               *ptr++ = val;
-       }
-
-       return (int) (*bufp);           /* Error if we don't end at end of string. */
-}
-#endif