summaryrefslogtreecommitdiff
path: root/networking/interface.c
blob: 6c8e93879833cf236d74660cc17158a0a2dfddd9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
/* vi: set sw=4 ts=4: */
/*
 * stolen from net-tools-1.59 and stripped down for busybox by
 *			Erik Andersen <andersen@codepoet.org>
 *
 * Heavily modified by Manuel Novoa III       Mar 12, 2001
 *
 * Added print_bytes_scaled function to reduce code size.
 * Added some (potentially) missing defines.
 * Improved display support for -a and for a named interface.
 *
 * -----------------------------------------------------------
 *
 * ifconfig   This file contains an implementation of the command
 *              that either displays or sets the characteristics of
 *              one or more of the system's networking interfaces.
 *
 * Version:     $Id: interface.c,v 1.25 2004/08/26 21:45:21 andersen Exp $
 *
 * Author:      Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
 *              and others.  Copyright 1993 MicroWalt Corporation
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 *
 * Patched to support 'add' and 'del' keywords for INET(4) addresses
 * by Mrs. Brisby <mrs.brisby@nimh.org>
 *
 * {1.34} - 19980630 - Arnaldo Carvalho de Melo <acme@conectiva.com.br>
 *                     - gettext instead of catgets for i18n
 *          10/1998  - Andi Kleen. Use interface list primitives.
 *	    20001008 - Bernd Eckenfels, Patch from RH for setting mtu
 *			(default AF was wrong)
 */

#include "inet_common.h"
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <ctype.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <net/if.h>
#include <net/if_arp.h>
#include "busybox.h"

#ifdef CONFIG_FEATURE_IPV6
# define HAVE_AFINET6 1
#else
# undef HAVE_AFINET6
#endif

#define _PATH_PROCNET_DEV               "/proc/net/dev"
#define _PATH_PROCNET_IFINET6           "/proc/net/if_inet6"

#if HAVE_AFINET6

#ifndef _LINUX_IN6_H
/*
 *    This is in linux/include/net/ipv6.h.
 */

struct in6_ifreq {
	struct in6_addr ifr6_addr;
	uint32_t ifr6_prefixlen;
	unsigned int ifr6_ifindex;
};

#endif

#endif							/* HAVE_AFINET6 */

/* 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 HAVE_TXQUEUELEN
#define HAVE_TXQUEUELEN 1
#endif

#ifndef IFF_DYNAMIC
#define IFF_DYNAMIC     0x8000	/* dialup device with changing addresses */
#endif

/* This structure defines protocol families and their handlers. */
struct aftype {
	const char *name;
	const char *title;
	int af;
	int alen;
	char *(*print) (unsigned char *);
	char *(*sprint) (struct sockaddr *, int numeric);
	int (*input) (int type, char *bufp, struct sockaddr *);
	void (*herror) (char *text);
	int (*rprint) (int options);
	int (*rinput) (int typ, int ext, char **argv);

	/* may modify src */
	int (*getmask) (char *src, struct sockaddr * mask, char *name);

	int fd;
	char *flag_file;
};

/* Display an Internet socket address. */
static char *INET_sprint(struct sockaddr *sap, int numeric)
{
	static char buff[128];

	if (sap->sa_family == 0xFFFF || sap->sa_family == 0)
		return safe_strncpy(buff, "[NONE SET]", sizeof(buff));

	if (INET_rresolve(buff, sizeof(buff), (struct sockaddr_in *) sap,
					  numeric, 0xffffff00) != 0)
		return (NULL);

	return (buff);
}

static struct aftype inet_aftype = {
	.name =		"inet",
	.title =	"DARPA Internet",
	.af =		AF_INET,
	.alen =		4,
	.sprint =	INET_sprint,
	.fd =		-1
};

#if HAVE_AFINET6

/* Display an Internet socket address. */
/* dirty! struct sockaddr usually doesn't suffer for inet6 addresses, fst. */
static char *INET6_sprint(struct sockaddr *sap, int numeric)
{
	static char buff[128];

	if (sap->sa_family == 0xFFFF || sap->sa_family == 0)
		return safe_strncpy(buff, "[NONE SET]", sizeof(buff));
	if (INET6_rresolve
		(buff, sizeof(buff), (struct sockaddr_in6 *) sap, numeric) != 0)
		return safe_strncpy(buff, "[UNKNOWN]", sizeof(buff));
	return (buff);
}

static struct aftype inet6_aftype = {
	.name =		"inet6",
	.title =	"IPv6",
	.af =		AF_INET6,
	.alen =		sizeof(struct in6_addr),
	.sprint =	INET6_sprint,
	.fd =		-1
};

#endif							/* HAVE_AFINET6 */

/* Display an UNSPEC address. */
static char *UNSPEC_print(unsigned char *ptr)
{
	static char buff[sizeof(struct sockaddr) * 3 + 1];
	char *pos;
	unsigned int i;

	pos = buff;
	for (i = 0; i < sizeof(struct sockaddr); i++) {
		/* careful -- not every libc's sprintf returns # bytes written */
		sprintf(pos, "%02X-", (*ptr++ & 0377));
		pos += 3;
	}
	/* Erase trailing "-".  Works as long as sizeof(struct sockaddr) != 0 */
	*--pos = '\0';
	return (buff);
}

/* Display an UNSPEC socket address. */
static char *UNSPEC_sprint(struct sockaddr *sap, int numeric)
{
	static char buf[64];

	if (sap->sa_family == 0xFFFF || sap->sa_family == 0)
		return safe_strncpy(buf, "[NONE SET]", sizeof(buf));
	return (UNSPEC_print((unsigned char *)sap->sa_data));
}

static struct aftype unspec_aftype = {
	"unspec", "UNSPEC", AF_UNSPEC, 0,
	UNSPEC_print, UNSPEC_sprint, NULL, NULL,
	NULL,
};

static struct aftype * const aftypes[] = {
	&inet_aftype,
#if HAVE_AFINET6
	&inet6_aftype,
#endif
	&unspec_aftype,
	NULL
};

/* Check our protocol family table for this family. */
static struct aftype *get_afntype(int af)
{
	struct aftype * const *afp;

	afp = aftypes;
	while (*afp != NULL) {
		if ((*afp)->af == af)
			return (*afp);
		afp++;
	}
	return (NULL);
}

/* Check our protocol family table for this family and return its socket */
static int get_socket_for_af(int af)
{
	struct aftype * const *afp;

	afp = aftypes;
	while (*afp != NULL) {
		if ((*afp)->af == af)
			return (*afp)->fd;
		afp++;
	}
	return -1;
}

struct user_net_device_stats {
	unsigned long long rx_packets;	/* total packets received       */
	unsigned long long tx_packets;	/* total packets transmitted    */
	unsigned long long rx_bytes;	/* total bytes received         */
	unsigned long long tx_bytes;	/* total bytes transmitted      */
	unsigned long rx_errors;	/* bad packets received         */
	unsigned long tx_errors;	/* packet transmit problems     */
	unsigned long rx_dropped;	/* no space in linux buffers    */
	unsigned long tx_dropped;	/* no space available in linux  */
	unsigned long rx_multicast;	/* multicast packets received   */
	unsigned long rx_compressed;
	unsigned long tx_compressed;
	unsigned long collisions;

	/* detailed rx_errors: */
	unsigned long rx_length_errors;
	unsigned long rx_over_errors;	/* receiver ring buff overflow  */
	unsigned long rx_crc_errors;	/* recved pkt with crc error    */
	unsigned long rx_frame_errors;	/* recv'd frame alignment error */
	unsigned long rx_fifo_errors;	/* recv'r fifo overrun          */
	unsigned long rx_missed_errors;	/* receiver missed packet     */
	/* detailed tx_errors */
	unsigned long tx_aborted_errors;
	unsigned long tx_carrier_errors;
	unsigned long tx_fifo_errors;
	unsigned long tx_heartbeat_errors;
	unsigned long tx_window_errors;
};

struct interface {
	struct interface *next, *prev;
	char name[IFNAMSIZ];	/* interface name        */
	short type;			/* if type               */
	short flags;		/* various flags         */
	int metric;			/* routing metric        */
	int mtu;			/* MTU value             */
	int tx_queue_len;	/* transmit queue length */
	struct ifmap map;	/* hardware setup        */
	struct sockaddr addr;	/* IP address            */
	struct sockaddr dstaddr;	/* P-P IP address        */
	struct sockaddr broadaddr;	/* IP broadcast address  */
	struct sockaddr netmask;	/* IP network mask       */
	int has_ip;
	char hwaddr[32];	/* HW address            */
	int statistics_valid;
	struct user_net_device_stats stats;	/* statistics            */
	int keepalive;		/* keepalive value for SLIP */
	int outfill;		/* outfill value for SLIP */
};


int interface_opt_a = 0;	/* show all interfaces          */

static struct interface *int_list, *int_last;
static int skfd = -1;	/* generic raw socket desc.     */


static int sockets_open(int family)
{
	struct aftype * const *aft;
	int sfd = -1;
	static int force = -1;

	if (force < 0) {
		force = 0;
		if (get_linux_version_code() < KERNEL_VERSION(2,1,0))
			force = 1;
		if (access("/proc/net", R_OK))
			force = 1;
	}
	for (aft = aftypes; *aft; aft++) {
		struct aftype *af = *aft;
		int type = SOCK_DGRAM;

		if (af->af == AF_UNSPEC)
			continue;
		if (family && family != af->af)
			continue;
		if (af->fd != -1) {
			sfd = af->fd;
			continue;
		}
		/* Check some /proc file first to not stress kmod */
		if (!family && !force && af->flag_file) {
			if (access(af->flag_file, R_OK))
				continue;
		}
		af->fd = socket(af->af, type, 0);
		if (af->fd >= 0)
			sfd = af->fd;
	}
	if (sfd < 0) {
		bb_error_msg("no usable address families found");
	}
	return sfd;
}

#ifdef CONFIG_FEATURE_CLEAN_UP
static void sockets_close(void)
{
	struct aftype * const *aft;
	for (aft = aftypes; *aft != NULL; aft++) {
		struct aftype *af = *aft;
		if( af->fd != -1 ) {
			close(af->fd);
			af->fd = -1;
		}
	}
}
#endif

/* like strcmp(), but knows about numbers */
static int nstrcmp(const char *a, const char *b)
{
	const char *a_ptr = a;
	const char *b_ptr = b;

	while (*a == *b) {
		if (*a == '\0') {
			return 0;
		}
		if (!isdigit(*a) && isdigit(*(a+1))) {
			a_ptr = a+1;
			b_ptr = b+1;
		}
		a++;
		b++;
	}

	if (isdigit(*a) && isdigit(*b)) {
		return xatoul(a_ptr) > xatoul(b_ptr) ? 1 : -1;
	}
	return *a - *b;
}

static struct interface *add_interface(char *name)
{
	struct interface *ife, **nextp, *new;

	for (ife = int_last; ife; ife = ife->prev) {
		int n = nstrcmp(ife->name, name);

		if (n == 0)
			return ife;
		if (n < 0)
			break;
	}

	new = xzalloc(sizeof(*new));
	safe_strncpy(new->name, name, IFNAMSIZ);
	nextp = ife ? &ife->next : &int_list;
	new->prev = ife;
	new->next = *nextp;
	if (new->next)
		new->next->prev = new;
	else
		int_last = new;
	*nextp = new;
	return new;
}


static int if_readconf(void)
{
	int numreqs = 30;
	struct ifconf ifc;
	struct ifreq *ifr;
	int n, err = -1;
	int skfd2;

	/* SIOCGIFCONF currently seems to only work properly on AF_INET sockets
	   (as of 2.1.128) */
	skfd2 = get_socket_for_af(AF_INET);
	if (skfd2 < 0) {
		bb_perror_msg(("warning: no inet socket available"));
		/* Try to soldier on with whatever socket we can get hold of.  */
		skfd2 = sockets_open(0);
		if (skfd2 < 0)
			return -1;
	}

	ifc.ifc_buf = NULL;
	for (;;) {
		ifc.ifc_len = sizeof(struct ifreq) * numreqs;
		ifc.ifc_buf = xrealloc(ifc.ifc_buf, ifc.ifc_len);

		if (ioctl(skfd2, SIOCGIFCONF, &ifc) < 0) {
			perror("SIOCGIFCONF");
			goto out;
		}
		if (ifc.ifc_len == sizeof(struct ifreq) * numreqs) {
			/* assume it overflowed and try again */
			numreqs += 10;
			continue;
		}
		break;
	}

	ifr = ifc.ifc_req;
	for (n = 0; n < ifc.ifc_len; n += sizeof(struct ifreq)) {
		add_interface(ifr->ifr_name);
		ifr++;
	}
	err = 0;

  out:
	free(ifc.ifc_buf);
	return err;
}

static char *get_name(char *name, char *p)
{
	/* Extract <name> from nul-terminated p where p matches
	   <name>: after leading whitespace.
	   If match is not made, set name empty and return unchanged p */
	int namestart=0, nameend=0;
	while (isspace(p[namestart]))
		namestart++;
	nameend=namestart;
	while (p[nameend] && p[nameend]!=':' && !isspace(p[nameend]))
		nameend++;
	if (p[nameend]==':') {
		if ((nameend-namestart)<IFNAMSIZ) {
			memcpy(name,&p[namestart],nameend-namestart);
			name[nameend-namestart]='\0';
			p=&p[nameend];
		} else {
			/* Interface name too large */
			name[0]='\0';
		}
	} else {
		/* trailing ':' not found - return empty */
		name[0]='\0';
	}
	return p + 1;
}

/* If scanf supports size qualifiers for %n conversions, then we can
 * use a modified fmt that simply stores the position in the fields
 * having no associated fields in the proc string.  Of course, we need
 * to zero them again when we're done.  But that is smaller than the
 * old approach of multiple scanf occurrences with large numbers of
 * args. */

/* static const char * const ss_fmt[] = { */
/*	"%lln%llu%lu%lu%lu%lu%ln%ln%lln%llu%lu%lu%lu%lu%lu", */
/*	"%llu%llu%lu%lu%lu%lu%ln%ln%llu%llu%lu%lu%lu%lu%lu", */
/*	"%llu%llu%lu%lu%lu%lu%lu%lu%llu%llu%lu%lu%lu%lu%lu%lu" */
/* }; */

	/* Lie about the size of the int pointed to for %n. */
#if INT_MAX == LONG_MAX
static const char * const ss_fmt[] = {
	"%n%llu%u%u%u%u%n%n%n%llu%u%u%u%u%u",
	"%llu%llu%u%u%u%u%n%n%llu%llu%u%u%u%u%u",
	"%llu%llu%u%u%u%u%u%u%llu%llu%u%u%u%u%u%u"
};
#else
static const char * const ss_fmt[] = {
	"%n%llu%lu%lu%lu%lu%n%n%n%llu%lu%lu%lu%lu%lu",
	"%llu%llu%lu%lu%lu%lu%n%n%llu%llu%lu%lu%lu%lu%lu",
	"%llu%llu%lu%lu%lu%lu%lu%lu%llu%llu%lu%lu%lu%lu%lu%lu"
};

#endif

static void get_dev_fields(char *bp, struct interface *ife, int procnetdev_vsn)
{
	memset(&ife->stats, 0, sizeof(struct user_net_device_stats));

	sscanf(bp, ss_fmt[procnetdev_vsn],
		   &ife->stats.rx_bytes, /* missing for 0 */
		   &ife->stats.rx_packets,
		   &ife->stats.rx_errors,
		   &ife->stats.rx_dropped,
		   &ife->stats.rx_fifo_errors,
		   &ife->stats.rx_frame_errors,
		   &ife->stats.rx_compressed, /* missing for <= 1 */
		   &ife->stats.rx_multicast, /* missing for <= 1 */
		   &ife->stats.tx_bytes, /* missing for 0 */
		   &ife->stats.tx_packets,
		   &ife->stats.tx_errors,
		   &ife->stats.tx_dropped,
		   &ife->stats.tx_fifo_errors,
		   &ife->stats.collisions,
		   &ife->stats.tx_carrier_errors,
		   &ife->stats.tx_compressed /* missing for <= 1 */
		   );

	if (procnetdev_vsn <= 1) {
		if (procnetdev_vsn == 0) {
			ife->stats.rx_bytes = 0;
			ife->stats.tx_bytes = 0;
		}
		ife->stats.rx_multicast = 0;
		ife->stats.rx_compressed = 0;
		ife->stats.tx_compressed = 0;
	}
}

static inline int procnetdev_version(char *buf)
{
	if (strstr(buf, "compressed"))
		return 2;
	if (strstr(buf, "bytes"))
		return 1;
	return 0;
}

static int if_readlist_proc(char *target)
{
	static int proc_read;
	FILE *fh;
	char buf[512];
	struct interface *ife;
	int err, procnetdev_vsn;

	if (proc_read)
		return 0;
	if (!target)
		proc_read = 1;

	fh = fopen(_PATH_PROCNET_DEV, "r");
	if (!fh) {
		bb_perror_msg("warning: cannot open %s, limiting output", _PATH_PROCNET_DEV);
		return if_readconf();
	}
	fgets(buf, sizeof buf, fh);	/* eat line */
	fgets(buf, sizeof buf, fh);

	procnetdev_vsn = procnetdev_version(buf);

	err = 0;
	while (fgets(buf, sizeof buf, fh)) {
		char *s, name[128];

		s = get_name(name, buf);
		ife = add_interface(name);
		get_dev_fields(s, ife, procnetdev_vsn);
		ife->statistics_valid = 1;
		if (target && !strcmp(target, name))
			break;
	}
	if (ferror(fh)) {
		perror(_PATH_PROCNET_DEV);
		err = -1;
		proc_read = 0;
	}
	fclose(fh);
	return err;
}

static int if_readlist(void)
{
	int err = if_readlist_proc(NULL);

	if (!err)
		err = if_readconf();
	return err;
}

static int for_all_interfaces(int (*doit) (struct interface *, void *),
							  void *cookie)
{
	struct interface *ife;

	if (!int_list && (if_readlist() < 0))
		return -1;
	for (ife = int_list; ife; ife = ife->next) {
		int err = doit(ife, cookie);

		if (err)
			return err;
	}
	return 0;
}

/* Fetch the interface configuration from the kernel. */
static int if_fetch(struct interface *ife)
{
	struct ifreq ifr;
	int fd;
	char *ifname = ife->name;

	strcpy(ifr.ifr_name, ifname);
	if (ioctl(skfd, SIOCGIFFLAGS, &ifr) < 0)
		return (-1);
	ife->flags = ifr.ifr_flags;

	strcpy(ifr.ifr_name, ifname);
	if (ioctl(skfd, SIOCGIFHWADDR, &ifr) < 0)
		memset(ife->hwaddr, 0, 32);
	else
		memcpy(ife->hwaddr, ifr.ifr_hwaddr.sa_data, 8);

	ife->type = ifr.ifr_hwaddr.sa_family;

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

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

#ifdef SIOCGIFMAP
	strcpy(ifr.ifr_name, ifname);
	if (ioctl(skfd, SIOCGIFMAP, &ifr) == 0)
		ife->map = ifr.ifr_map;
	else
#endif
		memset(&ife->map, 0, sizeof(struct ifmap));

#ifdef HAVE_TXQUEUELEN
	strcpy(ifr.ifr_name, ifname);
	if (ioctl(skfd, SIOCGIFTXQLEN, &ifr) < 0)
		ife->tx_queue_len = -1;	/* unknown value */
	else
		ife->tx_queue_len = ifr.ifr_qlen;
#else
	ife->tx_queue_len = -1;	/* unknown value */
#endif

	/* IPv4 address? */
	fd = get_socket_for_af(AF_INET);
	if (fd >= 0) {
		strcpy(ifr.ifr_name, ifname);
		ifr.ifr_addr.sa_family = AF_INET;
		if (ioctl(fd, SIOCGIFADDR, &ifr) == 0) {
			ife->has_ip = 1;
			ife->addr = ifr.ifr_addr;
			strcpy(ifr.ifr_name, ifname);
			if (ioctl(fd, SIOCGIFDSTADDR, &ifr) < 0)
				memset(&ife->dstaddr, 0, sizeof(struct sockaddr));
			else
				ife->dstaddr = ifr.ifr_dstaddr;

			strcpy(ifr.ifr_name, ifname);
			if (ioctl(fd, SIOCGIFBRDADDR, &ifr) < 0)
				memset(&ife->broadaddr, 0, sizeof(struct sockaddr));
			else
				ife->broadaddr = ifr.ifr_broadaddr;

			strcpy(ifr.ifr_name, ifname);
			if (ioctl(fd, SIOCGIFNETMASK, &ifr) < 0)
				memset(&ife->netmask, 0, sizeof(struct sockaddr));
			else
				ife->netmask = ifr.ifr_netmask;
		} else
			memset(&ife->addr, 0, sizeof(struct sockaddr));
	}

	return 0;
}


static int do_if_fetch(struct interface *ife)
{
	if (if_fetch(ife) < 0) {
		char *errmsg;

		if (errno == ENODEV) {
			/* Give better error message for this case. */
			errmsg = "Device not found";
		} else {
			errmsg = strerror(errno);
		}
		bb_error_msg("%s: error fetching interface information: %s",
				ife->name, errmsg);
		return -1;
	}
	return 0;
}

/* This structure defines hardware protocols and their handlers. */
struct hwtype {
	const char * const name;
	const char *title;
	int type;
	int alen;
	char *(*print) (unsigned char *);
	int (*input) (char *, struct sockaddr *);
	int (*activate) (int fd);
	int suppress_null_addr;
};

static const struct hwtype unspec_hwtype = {
	.name =		"unspec",
	.title =	"UNSPEC",
	.type =		-1,
	.print =	UNSPEC_print
};

static const struct hwtype loop_hwtype = {
	.name =		"loop",
	.title =	"Local Loopback",
	.type =		ARPHRD_LOOPBACK
};

#include <net/if_arp.h>

#if (__GLIBC__ >=2 && __GLIBC_MINOR >= 1) || defined(_NEWLIB_VERSION)
#include <net/ethernet.h>
#else
#include <linux/if_ether.h>
#endif

/* Display an Ethernet address in readable format. */
static char *pr_ether(unsigned char *ptr)
{
	static char buff[64];

	snprintf(buff, sizeof(buff), "%02X:%02X:%02X:%02X:%02X:%02X",
			 (ptr[0] & 0377), (ptr[1] & 0377), (ptr[2] & 0377),
			 (ptr[3] & 0377), (ptr[4] & 0377), (ptr[5] & 0377)
		);
	return (buff);
}

static const struct hwtype ether_hwtype = {
	.name =		"ether",
	.title =	"Ethernet",
	.type =		ARPHRD_ETHER,
	.alen =		ETH_ALEN,
	.print =	pr_ether
};

#include <net/if_arp.h>

static const struct hwtype ppp_hwtype = {
	.name =		"ppp",
	.title =	"Point-to-Point Protocol",
	.type =		ARPHRD_PPP
};

#ifdef CONFIG_FEATURE_IPV6
static const struct hwtype sit_hwtype = {
	.name =			"sit",
	.title =		"IPv6-in-IPv4",
	.type =			ARPHRD_SIT,
	.print =		UNSPEC_print,
	.suppress_null_addr =	1
} ;
#endif

static const struct hwtype * const hwtypes[] = {
	&loop_hwtype,
	&ether_hwtype,
	&ppp_hwtype,
	&unspec_hwtype,
#ifdef CONFIG_FEATURE_IPV6
	&sit_hwtype,
#endif
	NULL
};

#ifdef IFF_PORTSEL
static const char * const if_port_text[] = {
	/* Keep in step with <linux/netdevice.h> */
	"unknown",
	"10base2",
	"10baseT",
	"AUI",
	"100baseT",
	"100baseTX",
	"100baseFX",
	NULL
};
#endif

/* Check our hardware type table for this type. */
static const struct hwtype *get_hwntype(int type)
{
	const struct hwtype * const *hwp;

	hwp = hwtypes;
	while (*hwp != NULL) {
		if ((*hwp)->type == type)
			return (*hwp);
		hwp++;
	}
	return (NULL);
}

/* return 1 if address is all zeros */
static int hw_null_address(const struct hwtype *hw, void *ap)
{
	unsigned int i;
	unsigned char *address = (unsigned char *) ap;

	for (i = 0; i < hw->alen; i++)
		if (address[i])
			return 0;
	return 1;
}

static const char TRext[] = "\0\0\0Ki\0Mi\0Gi\0Ti";

static void print_bytes_scaled(unsigned long long ull, const char *end)
{
	unsigned long long int_part;
	const char *ext;
	unsigned int frac_part;
	int i;

	frac_part = 0;
	ext = TRext;
	int_part = ull;
	i = 4;
	do {
		if (int_part >= 1024) {
			frac_part = ((((unsigned int) int_part) & (1024-1)) * 10) / 1024;
			int_part /= 1024;
			ext += 3;	/* KiB, MiB, GiB, TiB */
		}
		--i;
	} while (i);

	printf("X bytes:%llu (%llu.%u %sB)%s", ull, int_part, frac_part, ext, end);
}

static const char * const ife_print_flags_strs[] = {
	"UP ",
	"BROADCAST ",
	"DEBUG ",
	"LOOPBACK ",
	"POINTOPOINT ",
	"NOTRAILERS ",
	"RUNNING ",
	"NOARP ",
	"PROMISC ",
	"ALLMULTI ",
	"SLAVE ",
	"MASTER ",
	"MULTICAST ",
#ifdef HAVE_DYNAMIC
	"DYNAMIC "
#endif
};

static const unsigned short ife_print_flags_mask[] = {
	IFF_UP,
	IFF_BROADCAST,
	IFF_DEBUG,
	IFF_LOOPBACK,
	IFF_POINTOPOINT,
	IFF_NOTRAILERS,
	IFF_RUNNING,
	IFF_NOARP,
	IFF_PROMISC,
	IFF_ALLMULTI,
	IFF_SLAVE,
	IFF_MASTER,
	IFF_MULTICAST,
#ifdef HAVE_DYNAMIC
	IFF_DYNAMIC
#endif
	0
};

static void ife_print(struct interface *ptr)
{
	struct aftype *ap;
	const struct hwtype *hw;
	int hf;
	int can_compress = 0;

#if HAVE_AFINET6
	FILE *f;
	char addr6[40], devname[20];
	struct sockaddr_in6 sap;
	int plen, scope, dad_status, if_idx;
	char addr6p[8][5];
#endif

	ap = get_afntype(ptr->addr.sa_family);
	if (ap == NULL)
		ap = get_afntype(0);

	hf = ptr->type;

	if (hf == ARPHRD_CSLIP || hf == ARPHRD_CSLIP6)
		can_compress = 1;

	hw = get_hwntype(hf);
	if (hw == NULL)
		hw = get_hwntype(-1);

	printf("%-9.9s Link encap:%s  ", ptr->name, hw->title);
	/* For some hardware types (eg Ash, ATM) we don't print the
	   hardware address if it's null.  */
	if (hw->print != NULL && (!(hw_null_address(hw, ptr->hwaddr) &&
								hw->suppress_null_addr)))
		printf("HWaddr %s  ", hw->print((unsigned char *)ptr->hwaddr));
#ifdef IFF_PORTSEL
	if (ptr->flags & IFF_PORTSEL) {
		printf("Media:%s", if_port_text[ptr->map.port] /* [0] */);
		if (ptr->flags & IFF_AUTOMEDIA)
			printf("(auto)");
	}
#endif
	puts("");

	if (ptr->has_ip) {
		printf("          %s addr:%s ", ap->name,
			   ap->sprint(&ptr->addr, 1));
		if (ptr->flags & IFF_POINTOPOINT) {
			printf(" P-t-P:%s ", ap->sprint(&ptr->dstaddr, 1));
		}
		if (ptr->flags & IFF_BROADCAST) {
			printf(" Bcast:%s ", ap->sprint(&ptr->broadaddr, 1));
		}
		printf(" Mask:%s\n", ap->sprint(&ptr->netmask, 1));
	}

#if HAVE_AFINET6

#define IPV6_ADDR_ANY           0x0000U

#define IPV6_ADDR_UNICAST       0x0001U
#define IPV6_ADDR_MULTICAST     0x0002U
#define IPV6_ADDR_ANYCAST       0x0004U

#define IPV6_ADDR_LOOPBACK      0x0010U
#define IPV6_ADDR_LINKLOCAL     0x0020U
#define IPV6_ADDR_SITELOCAL     0x0040U

#define IPV6_ADDR_COMPATv4      0x0080U

#define IPV6_ADDR_SCOPE_MASK    0x00f0U

#define IPV6_ADDR_MAPPED        0x1000U
#define IPV6_ADDR_RESERVED      0x2000U	/* reserved address space */

	if ((f = fopen(_PATH_PROCNET_IFINET6, "r")) != NULL) {
		while (fscanf
			   (f, "%4s%4s%4s%4s%4s%4s%4s%4s %02x %02x %02x %02x %20s\n",
				addr6p[0], addr6p[1], addr6p[2], addr6p[3], addr6p[4],
				addr6p[5], addr6p[6], addr6p[7], &if_idx, &plen, &scope,
				&dad_status, devname) != EOF) {
			if (!strcmp(devname, ptr->name)) {
				sprintf(addr6, "%s:%s:%s:%s:%s:%s:%s:%s",
						addr6p[0], addr6p[1], addr6p[2], addr6p[3],
						addr6p[4], addr6p[5], addr6p[6], addr6p[7]);
				inet_pton(AF_INET6, addr6,
						  (struct sockaddr *) &sap.sin6_addr);
				sap.sin6_family = AF_INET6;
				printf("          inet6 addr: %s/%d",
					   inet6_aftype.sprint((struct sockaddr *) &sap, 1),
					   plen);
				printf(" Scope:");
				switch (scope & IPV6_ADDR_SCOPE_MASK) {
				case 0:
					printf("Global");
					break;
				case IPV6_ADDR_LINKLOCAL:
					printf("Link");
					break;
				case IPV6_ADDR_SITELOCAL:
					printf("Site");
					break;
				case IPV6_ADDR_COMPATv4:
					printf("Compat");
					break;
				case IPV6_ADDR_LOOPBACK:
					printf("Host");
					break;
				default:
					printf("Unknown");
				}
				puts("");
			}
		}
		fclose(f);
	}
#endif

	printf("          ");
	/* DONT FORGET TO ADD THE FLAGS IN ife_print_short, too */

	if (ptr->flags == 0) {
		printf("[NO FLAGS] ");
	} else {
		int i = 0;
		do {
			if (ptr->flags & ife_print_flags_mask[i]) {
				printf(ife_print_flags_strs[i]);
			}
		} while (ife_print_flags_mask[++i]);
	}

	/* DONT FORGET TO ADD THE FLAGS IN ife_print_short */
	printf(" MTU:%d  Metric:%d", ptr->mtu, ptr->metric ? ptr->metric : 1);
#ifdef SIOCSKEEPALIVE
	if (ptr->outfill || ptr->keepalive)
		printf("  Outfill:%d  Keepalive:%d", ptr->outfill, ptr->keepalive);
#endif
	puts("");

	/* If needed, display the interface statistics. */

	if (ptr->statistics_valid) {
		/* XXX: statistics are currently only printed for the primary address,
		 *      not for the aliases, although strictly speaking they're shared
		 *      by all addresses.
		 */
		printf("          ");

		printf("RX packets:%llu errors:%lu dropped:%lu overruns:%lu frame:%lu\n",
			   ptr->stats.rx_packets, ptr->stats.rx_errors,
			   ptr->stats.rx_dropped, ptr->stats.rx_fifo_errors,
			   ptr->stats.rx_frame_errors);
		if (can_compress)
			printf("             compressed:%lu\n",
				   ptr->stats.rx_compressed);
		printf("          ");
		printf("TX packets:%llu errors:%lu dropped:%lu overruns:%lu carrier:%lu\n",
			   ptr->stats.tx_packets, ptr->stats.tx_errors,
			   ptr->stats.tx_dropped, ptr->stats.tx_fifo_errors,
			   ptr->stats.tx_carrier_errors);
		printf("          collisions:%lu ", ptr->stats.collisions);
		if (can_compress)
			printf("compressed:%lu ", ptr->stats.tx_compressed);
		if (ptr->tx_queue_len != -1)
			printf("txqueuelen:%d ", ptr->tx_queue_len);
		printf("\n          R");
		print_bytes_scaled(ptr->stats.rx_bytes, "  T");
		print_bytes_scaled(ptr->stats.tx_bytes, "\n");

	}

	if ((ptr->map.irq || ptr->map.mem_start || ptr->map.dma ||
		 ptr->map.base_addr)) {
		printf("          ");
		if (ptr->map.irq)
			printf("Interrupt:%d ", ptr->map.irq);
		if (ptr->map.base_addr >= 0x100)	/* Only print devices using it for
											   I/O maps */
			printf("Base address:0x%lx ",
				   (unsigned long) ptr->map.base_addr);
		if (ptr->map.mem_start) {
			printf("Memory:%lx-%lx ", ptr->map.mem_start,
				   ptr->map.mem_end);
		}
		if (ptr->map.dma)
			printf("DMA chan:%x ", ptr->map.dma);
		puts("");
	}
	puts("");
}


static int do_if_print(struct interface *ife, void *cookie)
{
	int *opt_a = (int *) cookie;
	int res;

	res = do_if_fetch(ife);
	if (res >= 0) {
		if ((ife->flags & IFF_UP) || *opt_a)
			ife_print(ife);
	}
	return res;
}

static struct interface *lookup_interface(char *name)
{
	struct interface *ife = NULL;

	if (if_readlist_proc(name) < 0)
		return NULL;
	ife = add_interface(name);
	return ife;
}

/* for ipv4 add/del modes */
static int if_print(char *ifname)
{
	int res;

	if (!ifname) {
		res = for_all_interfaces(do_if_print, &interface_opt_a);
	} else {
		struct interface *ife;

		ife = lookup_interface(ifname);
		res = do_if_fetch(ife);
		if (res >= 0)
			ife_print(ife);
	}
	return res;
}

int display_interfaces(char *ifname);
int display_interfaces(char *ifname)
{
	int status;

	/* Create a channel to the NET kernel. */
	if ((skfd = sockets_open(0)) < 0) {
		bb_perror_msg_and_die("socket");
	}

	/* Do we have to show the current setup? */
	status = if_print(ifname);
#ifdef CONFIG_FEATURE_CLEAN_UP
	sockets_close();
#endif
	exit(status < 0);
}