summaryrefslogtreecommitdiffstats
path: root/libnetutils/ifc_utils.c
blob: 4d004f6391d3849533f7d393fa89e5b3d2fa0988 (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
/*
 * Copyright 2008, The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); 
 * you may not use this file except in compliance with the License. 
 * You may obtain a copy of the License at 
 *
 *     http://www.apache.org/licenses/LICENSE-2.0 
 *
 * Unless required by applicable law or agreed to in writing, software 
 * distributed under the License is distributed on an "AS IS" BASIS, 
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
 * See the License for the specific language governing permissions and 
 * limitations under the License.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>

#include <sys/socket.h>
#include <sys/select.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <netdb.h>

#include <linux/if.h>
#include <linux/if_ether.h>
#include <linux/if_arp.h>
#include <linux/netlink.h>
#include <linux/route.h>
#include <linux/ipv6_route.h>
#include <linux/rtnetlink.h>
#include <linux/sockios.h>

#include "netutils/ifc.h"

#ifdef ANDROID
#define LOG_TAG "NetUtils"
#include <cutils/log.h>
#include <cutils/properties.h>
#else
#include <stdio.h>
#include <string.h>
#define ALOGD printf
#define ALOGW printf
#endif

#ifdef HAVE_ANDROID_OS
/* SIOCKILLADDR is an Android extension. */
#define SIOCKILLADDR 0x8939
#endif

static int ifc_ctl_sock = -1;
static int ifc_ctl_sock6 = -1;
void printerr(char *fmt, ...);

#define DBG 0
#define INET_ADDRLEN 4
#define INET6_ADDRLEN 16

in_addr_t prefixLengthToIpv4Netmask(int prefix_length)
{
    in_addr_t mask = 0;

    // C99 (6.5.7): shifts of 32 bits have undefined results
    if (prefix_length <= 0 || prefix_length > 32) {
        return 0;
    }

    mask = ~mask << (32 - prefix_length);
    mask = htonl(mask);

    return mask;
}

int ipv4NetmaskToPrefixLength(in_addr_t mask)
{
    int prefixLength = 0;
    uint32_t m = (uint32_t)ntohl(mask);
    while (m & 0x80000000) {
        prefixLength++;
        m = m << 1;
    }
    return prefixLength;
}

static const char *ipaddr_to_string(in_addr_t addr)
{
    struct in_addr in_addr;

    in_addr.s_addr = addr;
    return inet_ntoa(in_addr);
}

int string_to_ip(const char *string, struct sockaddr_storage *ss) {
    struct addrinfo hints, *ai;
    int ret;

    if (ss == NULL) {
        return -EFAULT;
    }

    memset(&hints, 0, sizeof(hints));
    hints.ai_family = AF_UNSPEC;
    hints.ai_flags = AI_NUMERICHOST;
    hints.ai_socktype = SOCK_DGRAM;

    ret = getaddrinfo(string, NULL, &hints, &ai);
    if (ret == 0) {
        memcpy(ss, ai->ai_addr, ai->ai_addrlen);
        freeaddrinfo(ai);
    }

    return ret;
}

int ifc_init(void)
{
    int ret;
    if (ifc_ctl_sock == -1) {
        ifc_ctl_sock = socket(AF_INET, SOCK_DGRAM, 0);
        if (ifc_ctl_sock < 0) {
            printerr("socket() failed: %s\n", strerror(errno));
        }
    }

    ret = ifc_ctl_sock < 0 ? -1 : 0;
    if (DBG) printerr("ifc_init_returning %d", ret);
    return ret;
}

int ifc_init6(void)
{
    if (ifc_ctl_sock6 == -1) {
        ifc_ctl_sock6 = socket(AF_INET6, SOCK_DGRAM, 0);
        if (ifc_ctl_sock6 < 0) {
            printerr("socket() failed: %s\n", strerror(errno));
        }
    }
    return ifc_ctl_sock6 < 0 ? -1 : 0;
}

void ifc_close(void)
{
    if (DBG) printerr("ifc_close");
    if (ifc_ctl_sock != -1) {
        (void)close(ifc_ctl_sock);
        ifc_ctl_sock = -1;
    }
}

void ifc_close6(void)
{
    if (ifc_ctl_sock6 != -1) {
        (void)close(ifc_ctl_sock6);
        ifc_ctl_sock6 = -1;
    }
}

static void ifc_init_ifr(const char *name, struct ifreq *ifr)
{
    memset(ifr, 0, sizeof(struct ifreq));
    strncpy(ifr->ifr_name, name, IFNAMSIZ);
    ifr->ifr_name[IFNAMSIZ - 1] = 0;
}

int ifc_get_hwaddr(const char *name, void *ptr)
{
    int r;
    struct ifreq ifr;
    ifc_init_ifr(name, &ifr);

    r = ioctl(ifc_ctl_sock, SIOCGIFHWADDR, &ifr);
    if(r < 0) return -1;

    memcpy(ptr, &ifr.ifr_hwaddr.sa_data, ETH_ALEN);
    return 0;
}

int ifc_get_ifindex(const char *name, int *if_indexp)
{
    int r;
    struct ifreq ifr;
    ifc_init_ifr(name, &ifr);

    r = ioctl(ifc_ctl_sock, SIOCGIFINDEX, &ifr);
    if(r < 0) return -1;

    *if_indexp = ifr.ifr_ifindex;
    return 0;
}

static int ifc_set_flags(const char *name, unsigned set, unsigned clr)
{
    struct ifreq ifr;
    ifc_init_ifr(name, &ifr);

    if(ioctl(ifc_ctl_sock, SIOCGIFFLAGS, &ifr) < 0) return -1;
    ifr.ifr_flags = (ifr.ifr_flags & (~clr)) | set;
    return ioctl(ifc_ctl_sock, SIOCSIFFLAGS, &ifr);
}

int ifc_up(const char *name)
{
    int ret = ifc_set_flags(name, IFF_UP, 0);
    if (DBG) printerr("ifc_up(%s) = %d", name, ret);
    return ret;
}

int ifc_down(const char *name)
{
    int ret = ifc_set_flags(name, 0, IFF_UP);
    if (DBG) printerr("ifc_down(%s) = %d", name, ret);
    return ret;
}

static void init_sockaddr_in(struct sockaddr *sa, in_addr_t addr)
{
    struct sockaddr_in *sin = (struct sockaddr_in *) sa;
    sin->sin_family = AF_INET;
    sin->sin_port = 0;
    sin->sin_addr.s_addr = addr;
}

int ifc_set_addr(const char *name, in_addr_t addr)
{
    struct ifreq ifr;
    int ret;

    ifc_init_ifr(name, &ifr);
    init_sockaddr_in(&ifr.ifr_addr, addr);

    ret = ioctl(ifc_ctl_sock, SIOCSIFADDR, &ifr);
    if (DBG) printerr("ifc_set_addr(%s, xx) = %d", name, ret);
    return ret;
}

/*
 * Adds or deletes an IP address on an interface.
 *
 * Action is one of:
 * - RTM_NEWADDR (to add a new address)
 * - RTM_DELADDR (to delete an existing address)
 *
 * Returns zero on success and negative errno on failure.
 */
int ifc_act_on_address(int action, const char *name, const char *address,
                       int prefixlen) {
    int ifindex, s, len, ret;
    struct sockaddr_storage ss;
    void *addr;
    size_t addrlen;
    struct {
        struct nlmsghdr n;
        struct ifaddrmsg r;
        // Allow for IPv6 address, headers, and padding.
        char attrbuf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
                     NLMSG_ALIGN(sizeof(struct rtattr)) +
                     NLMSG_ALIGN(INET6_ADDRLEN)];
    } req;
    struct rtattr *rta;
    struct nlmsghdr *nh;
    struct nlmsgerr *err;
    char buf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
             NLMSG_ALIGN(sizeof(struct nlmsgerr)) +
             NLMSG_ALIGN(sizeof(struct nlmsghdr))];

    // Get interface ID.
    ifindex = if_nametoindex(name);
    if (ifindex == 0) {
        return -errno;
    }

    // Convert string representation to sockaddr_storage.
    ret = string_to_ip(address, &ss);
    if (ret) {
        return ret;
    }

    // Determine address type and length.
    if (ss.ss_family == AF_INET) {
        struct sockaddr_in *sin = (struct sockaddr_in *) &ss;
        addr = &sin->sin_addr;
        addrlen = INET_ADDRLEN;
    } else if (ss.ss_family == AF_INET6) {
        struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) &ss;
        addr = &sin6->sin6_addr;
        addrlen = INET6_ADDRLEN;
    } else {
        return -EAFNOSUPPORT;
    }

    // Fill in netlink structures.
    memset(&req, 0, sizeof(req));

    // Netlink message header.
    req.n.nlmsg_len = NLMSG_LENGTH(sizeof(req.r));
    req.n.nlmsg_type = action;
    req.n.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
    req.n.nlmsg_pid = getpid();

    // Interface address message header.
    req.r.ifa_family = ss.ss_family;
    req.r.ifa_prefixlen = prefixlen;
    req.r.ifa_index = ifindex;

    // Routing attribute. Contains the actual IP address.
    rta = (struct rtattr *) (((char *) &req) + NLMSG_ALIGN(req.n.nlmsg_len));
    rta->rta_type = IFA_LOCAL;
    rta->rta_len = RTA_LENGTH(addrlen);
    req.n.nlmsg_len = NLMSG_ALIGN(req.n.nlmsg_len) + RTA_LENGTH(addrlen);
    memcpy(RTA_DATA(rta), addr, addrlen);

    s = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
    if (send(s, &req, req.n.nlmsg_len, 0) < 0) {
        close(s);
        return -errno;
    }

    len = recv(s, buf, sizeof(buf), 0);
    close(s);
    if (len < 0) {
        return -errno;
    }

    // Parse the acknowledgement to find the return code.
    nh = (struct nlmsghdr *) buf;
    if (!NLMSG_OK(nh, (unsigned) len) || nh->nlmsg_type != NLMSG_ERROR) {
        return -EINVAL;
    }
    err = NLMSG_DATA(nh);

    // Return code is negative errno.
    return err->error;
}

int ifc_add_address(const char *name, const char *address, int prefixlen) {
    return ifc_act_on_address(RTM_NEWADDR, name, address, prefixlen);
}

int ifc_del_address(const char *name, const char * address, int prefixlen) {
    return ifc_act_on_address(RTM_DELADDR, name, address, prefixlen);
}

/*
 * Clears IPv6 addresses on the specified interface.
 */
int ifc_clear_ipv6_addresses(const char *name) {
    char rawaddrstr[INET6_ADDRSTRLEN], addrstr[INET6_ADDRSTRLEN];
    unsigned int prefixlen;
    int lasterror = 0, i, j, ret;
    char ifname[64];  // Currently, IFNAMSIZ = 16.
    FILE *f = fopen("/proc/net/if_inet6", "r");
    if (!f) {
        return -errno;
    }

    // Format:
    // 20010db8000a0001fc446aa4b5b347ed 03 40 00 01    wlan0
    while (fscanf(f, "%32s %*02x %02x %*02x %*02x %63s\n",
                  rawaddrstr, &prefixlen, ifname) == 3) {
        // Is this the interface we're looking for?
        if (strcmp(name, ifname)) {
            continue;
        }

        // Put the colons back into the address.
        for (i = 0, j = 0; i < 32; i++, j++) {
            addrstr[j] = rawaddrstr[i];
            if (i % 4 == 3) {
                addrstr[++j] = ':';
            }
        }
        addrstr[j - 1] = '\0';

        // Don't delete the link-local address as well, or it will disable IPv6
        // on the interface.
        if (strncmp(addrstr, "fe80:", 5) == 0) {
            continue;
        }

        ret = ifc_del_address(ifname, addrstr, prefixlen);
        if (ret) {
            ALOGE("Deleting address %s/%d on %s: %s", addrstr, prefixlen, ifname,
                 strerror(-ret));
            lasterror = ret;
        }
    }

    fclose(f);
    return lasterror;
}

/*
 * Clears IPv4 addresses on the specified interface.
 */
void ifc_clear_ipv4_addresses(const char *name) {
    unsigned count, addr;
    ifc_init();
    for (count=0, addr=1;((addr != 0) && (count < 255)); count++) {
        if (ifc_get_addr(name, &addr) < 0)
            break;
        if (addr)
            ifc_set_addr(name, 0);
    }
    ifc_close();
}

/*
 * Clears all IP addresses on the specified interface.
 */
int ifc_clear_addresses(const char *name) {
    ifc_clear_ipv4_addresses(name);
    return ifc_clear_ipv6_addresses(name);
}

int ifc_set_hwaddr(const char *name, const void *ptr)
{
    int r;
    struct ifreq ifr;
    ifc_init_ifr(name, &ifr);

    ifr.ifr_hwaddr.sa_family = ARPHRD_ETHER;
    memcpy(&ifr.ifr_hwaddr.sa_data, ptr, ETH_ALEN);
    return ioctl(ifc_ctl_sock, SIOCSIFHWADDR, &ifr);
}

int ifc_set_mask(const char *name, in_addr_t mask)
{
    struct ifreq ifr;
    int ret;

    ifc_init_ifr(name, &ifr);
    init_sockaddr_in(&ifr.ifr_addr, mask);

    ret = ioctl(ifc_ctl_sock, SIOCSIFNETMASK, &ifr);
    if (DBG) printerr("ifc_set_mask(%s, xx) = %d", name, ret);
    return ret;
}

int ifc_set_prefixLength(const char *name, int prefixLength)
{
    struct ifreq ifr;
    // TODO - support ipv6
    if (prefixLength > 32 || prefixLength < 0) return -1;

    in_addr_t mask = prefixLengthToIpv4Netmask(prefixLength);
    ifc_init_ifr(name, &ifr);
    init_sockaddr_in(&ifr.ifr_addr, mask);

    return ioctl(ifc_ctl_sock, SIOCSIFNETMASK, &ifr);
}

int ifc_get_addr(const char *name, in_addr_t *addr)
{
    struct ifreq ifr;
    int ret = 0;

    ifc_init_ifr(name, &ifr);
    if (addr != NULL) {
        ret = ioctl(ifc_ctl_sock, SIOCGIFADDR, &ifr);
        if (ret < 0) {
            *addr = 0;
        } else {
            *addr = ((struct sockaddr_in*) &ifr.ifr_addr)->sin_addr.s_addr;
        }
    }
    return ret;
}

int ifc_get_info(const char *name, in_addr_t *addr, int *prefixLength, unsigned *flags)
{
    struct ifreq ifr;
    ifc_init_ifr(name, &ifr);

    if (addr != NULL) {
        if(ioctl(ifc_ctl_sock, SIOCGIFADDR, &ifr) < 0) {
            *addr = 0;
        } else {
            *addr = ((struct sockaddr_in*) &ifr.ifr_addr)->sin_addr.s_addr;
        }
    }

    if (prefixLength != NULL) {
        if(ioctl(ifc_ctl_sock, SIOCGIFNETMASK, &ifr) < 0) {
            *prefixLength = 0;
        } else {
            *prefixLength = ipv4NetmaskToPrefixLength(
                    ((struct sockaddr_in*) &ifr.ifr_addr)->sin_addr.s_addr);
        }
    }

    if (flags != NULL) {
        if(ioctl(ifc_ctl_sock, SIOCGIFFLAGS, &ifr) < 0) {
            *flags = 0;
        } else {
            *flags = ifr.ifr_flags;
        }
    }

    return 0;
}

int ifc_act_on_ipv4_route(int action, const char *ifname, struct in_addr dst, int prefix_length,
      struct in_addr gw)
{
    struct rtentry rt;
    int result;
    in_addr_t netmask;

    memset(&rt, 0, sizeof(rt));

    rt.rt_dst.sa_family = AF_INET;
    rt.rt_dev = (void*) ifname;

    netmask = prefixLengthToIpv4Netmask(prefix_length);
    init_sockaddr_in(&rt.rt_genmask, netmask);
    init_sockaddr_in(&rt.rt_dst, dst.s_addr);
    rt.rt_flags = RTF_UP;

    if (prefix_length == 32) {
        rt.rt_flags |= RTF_HOST;
    }

    if (gw.s_addr != 0) {
        rt.rt_flags |= RTF_GATEWAY;
        init_sockaddr_in(&rt.rt_gateway, gw.s_addr);
    }

    ifc_init();

    if (ifc_ctl_sock < 0) {
        return -errno;
    }

    result = ioctl(ifc_ctl_sock, action, &rt);
    if (result < 0) {
        if (errno == EEXIST) {
            result = 0;
        } else {
            result = -errno;
        }
    }
    ifc_close();
    return result;
}

/* deprecated - v4 only */
int ifc_create_default_route(const char *name, in_addr_t gw)
{
    struct in_addr in_dst, in_gw;

    in_dst.s_addr = 0;
    in_gw.s_addr = gw;

    int ret = ifc_act_on_ipv4_route(SIOCADDRT, name, in_dst, 0, in_gw);
    if (DBG) printerr("ifc_create_default_route(%s, %d) = %d", name, gw, ret);
    return ret;
}

/* deprecated v4-only */
int ifc_add_host_route(const char *name, in_addr_t dst)
{
    struct in_addr in_dst, in_gw;

    in_dst.s_addr = dst;
    in_gw.s_addr = 0;

    return ifc_act_on_ipv4_route(SIOCADDRT, name, in_dst, 32, in_gw);
}

int ifc_enable(const char *ifname)
{
    int result;

    ifc_init();
    result = ifc_up(ifname);
    ifc_close();
    return result;
}

int ifc_disable(const char *ifname)
{
    unsigned addr, count;
    int result;

    ifc_init();
    result = ifc_down(ifname);

    ifc_set_addr(ifname, 0);
    for (count=0, addr=1;((addr != 0) && (count < 255)); count++) {
       if (ifc_get_addr(ifname, &addr) < 0)
            break;
       if (addr)
          ifc_set_addr(ifname, 0);
    }

    ifc_close();
    return result;
}

int ifc_reset_connections(const char *ifname, const int reset_mask)
{
#ifdef HAVE_ANDROID_OS
    int result, success;
    in_addr_t myaddr;
    struct ifreq ifr;
    struct in6_ifreq ifr6;

    if (reset_mask & RESET_IPV4_ADDRESSES) {
        /* IPv4. Clear connections on the IP address. */
        ifc_init();
        ifc_get_info(ifname, &myaddr, NULL, NULL);
        ifc_init_ifr(ifname, &ifr);
        init_sockaddr_in(&ifr.ifr_addr, myaddr);
        result = ioctl(ifc_ctl_sock, SIOCKILLADDR,  &ifr);
        ifc_close();
    } else {
        result = 0;
    }

    if (reset_mask & RESET_IPV6_ADDRESSES) {
        /*
         * IPv6. On Linux, when an interface goes down it loses all its IPv6
         * addresses, so we don't know which connections belonged to that interface
         * So we clear all unused IPv6 connections on the device by specifying an
         * empty IPv6 address.
         */
        ifc_init6();
        // This implicitly specifies an address of ::, i.e., kill all IPv6 sockets.
        memset(&ifr6, 0, sizeof(ifr6));
        success = ioctl(ifc_ctl_sock6, SIOCKILLADDR,  &ifr6);
        if (result == 0) {
            result = success;
        }
        ifc_close6();
    }

    return result;
#else
    return 0;
#endif
}

/*
 * Remove the routes associated with the named interface.
 */
int ifc_remove_host_routes(const char *name)
{
    char ifname[64];
    in_addr_t dest, gway, mask;
    int flags, refcnt, use, metric, mtu, win, irtt;
    struct rtentry rt;
    FILE *fp;
    struct in_addr addr;

    fp = fopen("/proc/net/route", "r");
    if (fp == NULL)
        return -1;
    /* Skip the header line */
    if (fscanf(fp, "%*[^\n]\n") < 0) {
        fclose(fp);
        return -1;
    }
    ifc_init();
    for (;;) {
        int nread = fscanf(fp, "%63s%X%X%X%d%d%d%X%d%d%d\n",
                           ifname, &dest, &gway, &flags, &refcnt, &use, &metric, &mask,
                           &mtu, &win, &irtt);
        if (nread != 11) {
            break;
        }
        if ((flags & (RTF_UP|RTF_HOST)) != (RTF_UP|RTF_HOST)
                || strcmp(ifname, name) != 0) {
            continue;
        }
        memset(&rt, 0, sizeof(rt));
        rt.rt_dev = (void *)name;
        init_sockaddr_in(&rt.rt_dst, dest);
        init_sockaddr_in(&rt.rt_gateway, gway);
        init_sockaddr_in(&rt.rt_genmask, mask);
        addr.s_addr = dest;
        if (ioctl(ifc_ctl_sock, SIOCDELRT, &rt) < 0) {
            ALOGD("failed to remove route for %s to %s: %s",
                 ifname, inet_ntoa(addr), strerror(errno));
        }
    }
    fclose(fp);
    ifc_close();
    return 0;
}

/*
 * Return the address of the default gateway
 *
 * TODO: factor out common code from this and remove_host_routes()
 * so that we only scan /proc/net/route in one place.
 *
 * DEPRECATED
 */
int ifc_get_default_route(const char *ifname)
{
    char name[64];
    in_addr_t dest, gway, mask;
    int flags, refcnt, use, metric, mtu, win, irtt;
    int result;
    FILE *fp;

    fp = fopen("/proc/net/route", "r");
    if (fp == NULL)
        return 0;
    /* Skip the header line */
    if (fscanf(fp, "%*[^\n]\n") < 0) {
        fclose(fp);
        return 0;
    }
    ifc_init();
    result = 0;
    for (;;) {
        int nread = fscanf(fp, "%63s%X%X%X%d%d%d%X%d%d%d\n",
                           name, &dest, &gway, &flags, &refcnt, &use, &metric, &mask,
                           &mtu, &win, &irtt);
        if (nread != 11) {
            break;
        }
        if ((flags & (RTF_UP|RTF_GATEWAY)) == (RTF_UP|RTF_GATEWAY)
                && dest == 0
                && strcmp(ifname, name) == 0) {
            result = gway;
            break;
        }
    }
    fclose(fp);
    ifc_close();
    return result;
}

/*
 * Sets the specified gateway as the default route for the named interface.
 * DEPRECATED
 */
int ifc_set_default_route(const char *ifname, in_addr_t gateway)
{
    struct in_addr addr;
    int result;

    ifc_init();
    addr.s_addr = gateway;
    if ((result = ifc_create_default_route(ifname, gateway)) < 0) {
        ALOGD("failed to add %s as default route for %s: %s",
             inet_ntoa(addr), ifname, strerror(errno));
    }
    ifc_close();
    return result;
}

/*
 * Removes the default route for the named interface.
 */
int ifc_remove_default_route(const char *ifname)
{
    struct rtentry rt;
    int result;

    ifc_init();
    memset(&rt, 0, sizeof(rt));
    rt.rt_dev = (void *)ifname;
    rt.rt_flags = RTF_UP|RTF_GATEWAY;
    init_sockaddr_in(&rt.rt_dst, 0);
    if ((result = ioctl(ifc_ctl_sock, SIOCDELRT, &rt)) < 0) {
        ALOGD("failed to remove default route for %s: %s", ifname, strerror(errno));
    }
    ifc_close();
    return result;
}

int
ifc_configure(const char *ifname,
        in_addr_t address,
        uint32_t prefixLength,
        in_addr_t gateway,
        in_addr_t dns1,
        in_addr_t dns2) {

    char dns_prop_name[PROPERTY_KEY_MAX];

    ifc_init();

    if (ifc_up(ifname)) {
        printerr("failed to turn on interface %s: %s\n", ifname, strerror(errno));
        ifc_close();
        return -1;
    }
    if (ifc_set_addr(ifname, address)) {
        printerr("failed to set ipaddr %s: %s\n", ipaddr_to_string(address), strerror(errno));
        ifc_close();
        return -1;
    }
    if (ifc_set_prefixLength(ifname, prefixLength)) {
        printerr("failed to set prefixLength %d: %s\n", prefixLength, strerror(errno));
        ifc_close();
        return -1;
    }
    if (ifc_create_default_route(ifname, gateway)) {
        printerr("failed to set default route %s: %s\n", ipaddr_to_string(gateway), strerror(errno));
        ifc_close();
        return -1;
    }

    ifc_close();

    snprintf(dns_prop_name, sizeof(dns_prop_name), "net.%s.dns1", ifname);
    property_set(dns_prop_name, dns1 ? ipaddr_to_string(dns1) : "");
    snprintf(dns_prop_name, sizeof(dns_prop_name), "net.%s.dns2", ifname);
    property_set(dns_prop_name, dns2 ? ipaddr_to_string(dns2) : "");

    return 0;
}

int ifc_act_on_ipv6_route(int action, const char *ifname, struct in6_addr dst, int prefix_length,
      struct in6_addr gw)
{
    struct in6_rtmsg rtmsg;
    int result;
    int ifindex;

    memset(&rtmsg, 0, sizeof(rtmsg));

    ifindex = if_nametoindex(ifname);
    if (ifindex == 0) {
        printerr("if_nametoindex() failed: interface %s\n", ifname);
        return -ENXIO;
    }

    rtmsg.rtmsg_ifindex = ifindex;
    rtmsg.rtmsg_dst = dst;
    rtmsg.rtmsg_dst_len = prefix_length;
    rtmsg.rtmsg_flags = RTF_UP;

    if (prefix_length == 128) {
        rtmsg.rtmsg_flags |= RTF_HOST;
    }

    if (memcmp(&gw, &in6addr_any, sizeof(in6addr_any))) {
        rtmsg.rtmsg_flags |= RTF_GATEWAY;
        rtmsg.rtmsg_gateway = gw;
    }

    ifc_init6();

    if (ifc_ctl_sock6 < 0) {
        return -errno;
    }

    result = ioctl(ifc_ctl_sock6, action, &rtmsg);
    if (result < 0) {
        if (errno == EEXIST) {
            result = 0;
        } else {
            result = -errno;
        }
    }
    ifc_close6();
    return result;
}

int ifc_act_on_route(int action, const char *ifname, const char *dst, int prefix_length,
        const char *gw)
{
    int ret = 0;
    struct sockaddr_in ipv4_dst, ipv4_gw;
    struct sockaddr_in6 ipv6_dst, ipv6_gw;
    struct addrinfo hints, *addr_ai, *gw_ai;

    memset(&hints, 0, sizeof(hints));
    hints.ai_family = AF_UNSPEC;  /* Allow IPv4 or IPv6 */
    hints.ai_flags = AI_NUMERICHOST;

    ret = getaddrinfo(dst, NULL, &hints, &addr_ai);

    if (ret != 0) {
        printerr("getaddrinfo failed: invalid address %s\n", dst);
        return -EINVAL;
    }

    if (gw == NULL || (strlen(gw) == 0)) {
        if (addr_ai->ai_family == AF_INET6) {
            gw = "::";
        } else if (addr_ai->ai_family == AF_INET) {
            gw = "0.0.0.0";
        }
    }

    if (((addr_ai->ai_family == AF_INET6) && (prefix_length < 0 || prefix_length > 128)) ||
            ((addr_ai->ai_family == AF_INET) && (prefix_length < 0 || prefix_length > 32))) {
        printerr("ifc_add_route: invalid prefix length");
        freeaddrinfo(addr_ai);
        return -EINVAL;
    }

    ret = getaddrinfo(gw, NULL, &hints, &gw_ai);
    if (ret != 0) {
        printerr("getaddrinfo failed: invalid gateway %s\n", gw);
        freeaddrinfo(addr_ai);
        return -EINVAL;
    }

    if (addr_ai->ai_family != gw_ai->ai_family) {
        printerr("ifc_add_route: different address families: %s and %s\n", dst, gw);
        freeaddrinfo(addr_ai);
        freeaddrinfo(gw_ai);
        return -EINVAL;
    }

    if (addr_ai->ai_family == AF_INET6) {
        memcpy(&ipv6_dst, addr_ai->ai_addr, sizeof(struct sockaddr_in6));
        memcpy(&ipv6_gw, gw_ai->ai_addr, sizeof(struct sockaddr_in6));
        ret = ifc_act_on_ipv6_route(action, ifname, ipv6_dst.sin6_addr,
                prefix_length, ipv6_gw.sin6_addr);
    } else if (addr_ai->ai_family == AF_INET) {
        memcpy(&ipv4_dst, addr_ai->ai_addr, sizeof(struct sockaddr_in));
        memcpy(&ipv4_gw, gw_ai->ai_addr, sizeof(struct sockaddr_in));
        ret = ifc_act_on_ipv4_route(action, ifname, ipv4_dst.sin_addr,
                prefix_length, ipv4_gw.sin_addr);
    } else {
        printerr("ifc_add_route: getaddrinfo returned un supported address family %d\n",
                  addr_ai->ai_family);
        ret = -EAFNOSUPPORT;
    }

    freeaddrinfo(addr_ai);
    freeaddrinfo(gw_ai);
    return ret;
}

/*
 * DEPRECATED
 */
int ifc_add_ipv4_route(const char *ifname, struct in_addr dst, int prefix_length,
      struct in_addr gw)
{
    int i =ifc_act_on_ipv4_route(SIOCADDRT, ifname, dst, prefix_length, gw);
    if (DBG) printerr("ifc_add_ipv4_route(%s, xx, %d, xx) = %d", ifname, prefix_length, i);
    return i;
}

/*
 * DEPRECATED
 */
int ifc_add_ipv6_route(const char *ifname, struct in6_addr dst, int prefix_length,
      struct in6_addr gw)
{
    return ifc_act_on_ipv6_route(SIOCADDRT, ifname, dst, prefix_length, gw);
}

int ifc_add_route(const char *ifname, const char *dst, int prefix_length, const char *gw)
{
    int i = ifc_act_on_route(SIOCADDRT, ifname, dst, prefix_length, gw);
    if (DBG) printerr("ifc_add_route(%s, %s, %d, %s) = %d", ifname, dst, prefix_length, gw, i);
    return i;
}

int ifc_remove_route(const char *ifname, const char*dst, int prefix_length, const char *gw)
{
    return ifc_act_on_route(SIOCDELRT, ifname, dst, prefix_length, gw);
}