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