ifc_utils.c revision 6cf73eadc752b619bc7c38d0d1277891eccbf81d 
1/*
2 * Copyright 2008, The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *     http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <stdio.h>
18#include <stdlib.h>
19#include <unistd.h>
20#include <string.h>
21#include <errno.h>
22
23#include <sys/socket.h>
24#include <sys/select.h>
25#include <sys/types.h>
26#include <netinet/in.h>
27#include <arpa/inet.h>
28#include <net/if.h>
29
30#include <linux/if.h>
31#include <linux/if_ether.h>
32#include <linux/if_arp.h>
33#include <linux/sockios.h>
34#include <linux/route.h>
35#include <linux/ipv6_route.h>
36#include <netdb.h>
37#include <linux/wireless.h>
38
39#ifdef ANDROID
40#define LOG_TAG "NetUtils"
41#include <cutils/log.h>
42#include <cutils/properties.h>
43#else
44#include <stdio.h>
45#include <string.h>
46#define LOGD printf
47#define LOGW printf
48#endif
49
50static int ifc_ctl_sock = -1;
51static int ifc_ctl_sock6 = -1;
52void printerr(char *fmt, ...);
53
54in_addr_t prefixLengthToIpv4Netmask(int prefix_length)
55{
56    in_addr_t mask = 0;
57
58    // C99 (6.5.7): shifts of 32 bits have undefined results
59    if (prefix_length <= 0 || prefix_length > 32) {
60        return 0;
61    }
62
63    mask = ~mask << (32 - prefix_length);
64    mask = htonl(mask);
65
66    return mask;
67}
68
69int ipv4NetmaskToPrefixLength(in_addr_t mask)
70{
71    mask = ntohl(mask);
72    int prefixLength = 0;
73    uint32_t m = (uint32_t)mask;
74    while (m & 0x80000000) {
75        prefixLength++;
76        m = m << 1;
77    }
78    return prefixLength;
79}
80
81static const char *ipaddr_to_string(in_addr_t addr)
82{
83    struct in_addr in_addr;
84
85    in_addr.s_addr = addr;
86    return inet_ntoa(in_addr);
87}
88
89int ifc_init(void)
90{
91    if (ifc_ctl_sock == -1) {
92        ifc_ctl_sock = socket(AF_INET, SOCK_DGRAM, 0);
93        if (ifc_ctl_sock < 0) {
94            printerr("socket() failed: %s\n", strerror(errno));
95        }
96    }
97    return ifc_ctl_sock < 0 ? -1 : 0;
98}
99
100int ifc_init6(void)
101{
102    if (ifc_ctl_sock6 == -1) {
103        ifc_ctl_sock6 = socket(AF_INET6, SOCK_DGRAM, 0);
104        if (ifc_ctl_sock6 < 0) {
105            printerr("socket() failed: %s\n", strerror(errno));
106        }
107    }
108    return ifc_ctl_sock6 < 0 ? -1 : 0;
109}
110
111void ifc_close(void)
112{
113    if (ifc_ctl_sock != -1) {
114        (void)close(ifc_ctl_sock);
115        ifc_ctl_sock = -1;
116    }
117}
118
119void ifc_close6(void)
120{
121    if (ifc_ctl_sock6 != -1) {
122        (void)close(ifc_ctl_sock6);
123        ifc_ctl_sock6 = -1;
124    }
125}
126
127static void ifc_init_ifr(const char *name, struct ifreq *ifr)
128{
129    memset(ifr, 0, sizeof(struct ifreq));
130    strncpy(ifr->ifr_name, name, IFNAMSIZ);
131    ifr->ifr_name[IFNAMSIZ - 1] = 0;
132}
133
134int ifc_get_hwaddr(const char *name, void *ptr)
135{
136    int r;
137    struct ifreq ifr;
138    ifc_init_ifr(name, &ifr);
139
140    r = ioctl(ifc_ctl_sock, SIOCGIFHWADDR, &ifr);
141    if(r < 0) return -1;
142
143    memcpy(ptr, &ifr.ifr_hwaddr.sa_data, ETH_ALEN);
144    return 0;
145}
146
147int ifc_get_ifindex(const char *name, int *if_indexp)
148{
149    int r;
150    struct ifreq ifr;
151    ifc_init_ifr(name, &ifr);
152
153    r = ioctl(ifc_ctl_sock, SIOCGIFINDEX, &ifr);
154    if(r < 0) return -1;
155
156    *if_indexp = ifr.ifr_ifindex;
157    return 0;
158}
159
160static int ifc_set_flags(const char *name, unsigned set, unsigned clr)
161{
162    struct ifreq ifr;
163    ifc_init_ifr(name, &ifr);
164
165    if(ioctl(ifc_ctl_sock, SIOCGIFFLAGS, &ifr) < 0) return -1;
166    ifr.ifr_flags = (ifr.ifr_flags & (~clr)) | set;
167    return ioctl(ifc_ctl_sock, SIOCSIFFLAGS, &ifr);
168}
169
170int ifc_up(const char *name)
171{
172    return ifc_set_flags(name, IFF_UP, 0);
173}
174
175int ifc_down(const char *name)
176{
177    return ifc_set_flags(name, 0, IFF_UP);
178}
179
180static void init_sockaddr_in(struct sockaddr *sa, in_addr_t addr)
181{
182    struct sockaddr_in *sin = (struct sockaddr_in *) sa;
183    sin->sin_family = AF_INET;
184    sin->sin_port = 0;
185    sin->sin_addr.s_addr = addr;
186}
187
188int ifc_set_addr(const char *name, in_addr_t addr)
189{
190    struct ifreq ifr;
191
192    ifc_init_ifr(name, &ifr);
193    init_sockaddr_in(&ifr.ifr_addr, addr);
194
195    return ioctl(ifc_ctl_sock, SIOCSIFADDR, &ifr);
196}
197
198int ifc_set_hwaddr(const char *name, const void *ptr)
199{
200    int r;
201    struct ifreq ifr;
202    ifc_init_ifr(name, &ifr);
203
204    ifr.ifr_hwaddr.sa_family = ARPHRD_ETHER;
205    memcpy(&ifr.ifr_hwaddr.sa_data, ptr, ETH_ALEN);
206    return ioctl(ifc_ctl_sock, SIOCSIFHWADDR, &ifr);
207}
208
209int ifc_set_prefixLength(const char *name, int prefixLength)
210{
211    struct ifreq ifr;
212    // TODO - support ipv6
213    if (prefixLength > 32 || prefixLength < 0) return -1;
214
215    in_addr_t mask = prefixLengthToIpv4Netmask(prefixLength);
216    ifc_init_ifr(name, &ifr);
217    init_sockaddr_in(&ifr.ifr_addr, mask);
218
219    return ioctl(ifc_ctl_sock, SIOCSIFNETMASK, &ifr);
220}
221
222int ifc_get_addr(const char *name, in_addr_t *addr)
223{
224    struct ifreq ifr;
225    int ret = 0;
226
227    ifc_init_ifr(name, &ifr);
228    if (addr != NULL) {
229        ret = ioctl(ifc_ctl_sock, SIOCGIFADDR, &ifr);
230        if (ret < 0) {
231            *addr = 0;
232        } else {
233            *addr = ((struct sockaddr_in*) &ifr.ifr_addr)->sin_addr.s_addr;
234        }
235    }
236    return ret;
237}
238
239int ifc_get_info(const char *name, in_addr_t *addr, int *prefixLength, unsigned *flags)
240{
241    struct ifreq ifr;
242    ifc_init_ifr(name, &ifr);
243
244    if (addr != NULL) {
245        if(ioctl(ifc_ctl_sock, SIOCGIFADDR, &ifr) < 0) {
246            *addr = 0;
247        } else {
248            *addr = ((struct sockaddr_in*) &ifr.ifr_addr)->sin_addr.s_addr;
249        }
250    }
251
252    if (prefixLength != NULL) {
253        if(ioctl(ifc_ctl_sock, SIOCGIFNETMASK, &ifr) < 0) {
254            *prefixLength = 0;
255        } else {
256            *prefixLength = ipv4NetmaskToPrefixLength((int)
257                    ((struct sockaddr_in*) &ifr.ifr_addr)->sin_addr.s_addr);
258        }
259    }
260
261    if (flags != NULL) {
262        if(ioctl(ifc_ctl_sock, SIOCGIFFLAGS, &ifr) < 0) {
263            *flags = 0;
264        } else {
265            *flags = ifr.ifr_flags;
266        }
267    }
268
269    return 0;
270}
271
272int ifc_add_ipv4_route(const char *ifname, struct in_addr dst, int prefix_length,
273      struct in_addr gw)
274{
275    struct rtentry rt;
276    int result;
277    in_addr_t netmask;
278
279    memset(&rt, 0, sizeof(rt));
280
281    rt.rt_dst.sa_family = AF_INET;
282    rt.rt_dev = (void*) ifname;
283
284    netmask = prefixLengthToIpv4Netmask(prefix_length);
285    init_sockaddr_in(&rt.rt_genmask, netmask);
286    init_sockaddr_in(&rt.rt_dst, dst.s_addr);
287    rt.rt_flags = RTF_UP;
288
289    if (prefix_length == 32) {
290        rt.rt_flags |= RTF_HOST;
291    }
292
293    if (gw.s_addr != 0) {
294        rt.rt_flags |= RTF_GATEWAY;
295        init_sockaddr_in(&rt.rt_gateway, gw.s_addr);
296    }
297
298    ifc_init();
299
300    if (ifc_ctl_sock < 0) {
301        return -errno;
302    }
303
304    result = ioctl(ifc_ctl_sock, SIOCADDRT, &rt);
305    if (result < 0) {
306        if (errno == EEXIST) {
307            result = 0;
308        } else {
309            result = -errno;
310        }
311    }
312    ifc_close();
313    return result;
314}
315
316int ifc_create_default_route(const char *name, in_addr_t gw)
317{
318    struct in_addr in_dst, in_gw;
319
320    in_dst.s_addr = 0;
321    in_gw.s_addr = gw;
322
323    return ifc_add_ipv4_route(name, in_dst, 0, in_gw);
324}
325
326int ifc_add_host_route(const char *name, in_addr_t dst)
327{
328    struct in_addr in_dst, in_gw;
329
330    in_dst.s_addr = dst;
331    in_gw.s_addr = 0;
332
333    return ifc_add_ipv4_route(name, in_dst, 32, in_gw);
334}
335
336int ifc_enable(const char *ifname)
337{
338    int result;
339
340    ifc_init();
341    result = ifc_up(ifname);
342    ifc_close();
343    return result;
344}
345
346int ifc_disable(const char *ifname)
347{
348    unsigned addr, count;
349    int result;
350
351    ifc_init();
352    result = ifc_down(ifname);
353
354    ifc_set_addr(ifname, 0);
355    for (count=0, addr=1;((addr != 0) && (count < 255)); count++) {
356       if (ifc_get_addr(ifname, &addr) < 0)
357            break;
358       if (addr)
359          ifc_set_addr(ifname, 0);
360    }
361
362    ifc_close();
363    return result;
364}
365
366int ifc_reset_connections(const char *ifname)
367{
368#ifdef HAVE_ANDROID_OS
369    int result, success;
370    in_addr_t myaddr;
371    struct ifreq ifr;
372    struct in6_ifreq ifr6;
373
374    /* IPv4. Clear connections on the IP address. */
375    ifc_init();
376    ifc_get_info(ifname, &myaddr, NULL, NULL);
377    ifc_init_ifr(ifname, &ifr);
378    init_sockaddr_in(&ifr.ifr_addr, myaddr);
379    result = ioctl(ifc_ctl_sock, SIOCKILLADDR,  &ifr);
380    ifc_close();
381
382    /*
383     * IPv6. On Linux, when an interface goes down it loses all its IPv6
384     * addresses, so we don't know which connections belonged to that interface
385     * So we clear all unused IPv6 connections on the device by specifying an
386     * empty IPv6 address.
387     */
388    ifc_init6();
389    // This implicitly specifies an address of ::, i.e., kill all IPv6 sockets.
390    memset(&ifr6, 0, sizeof(ifr6));
391    success = ioctl(ifc_ctl_sock6, SIOCKILLADDR,  &ifr6);
392    if (result == 0) {
393        result = success;
394    }
395    ifc_close6();
396
397    return result;
398#else
399    return 0;
400#endif
401}
402
403/*
404 * Remove the routes associated with the named interface.
405 */
406int ifc_remove_host_routes(const char *name)
407{
408    char ifname[64];
409    in_addr_t dest, gway, mask;
410    int flags, refcnt, use, metric, mtu, win, irtt;
411    struct rtentry rt;
412    FILE *fp;
413    struct in_addr addr;
414
415    fp = fopen("/proc/net/route", "r");
416    if (fp == NULL)
417        return -1;
418    /* Skip the header line */
419    if (fscanf(fp, "%*[^\n]\n") < 0) {
420        fclose(fp);
421        return -1;
422    }
423    ifc_init();
424    for (;;) {
425        int nread = fscanf(fp, "%63s%X%X%X%d%d%d%X%d%d%d\n",
426                           ifname, &dest, &gway, &flags, &refcnt, &use, &metric, &mask,
427                           &mtu, &win, &irtt);
428        if (nread != 11) {
429            break;
430        }
431        if ((flags & (RTF_UP|RTF_HOST)) != (RTF_UP|RTF_HOST)
432                || strcmp(ifname, name) != 0) {
433            continue;
434        }
435        memset(&rt, 0, sizeof(rt));
436        rt.rt_dev = (void *)name;
437        init_sockaddr_in(&rt.rt_dst, dest);
438        init_sockaddr_in(&rt.rt_gateway, gway);
439        init_sockaddr_in(&rt.rt_genmask, mask);
440        addr.s_addr = dest;
441        if (ioctl(ifc_ctl_sock, SIOCDELRT, &rt) < 0) {
442            LOGD("failed to remove route for %s to %s: %s",
443                 ifname, inet_ntoa(addr), strerror(errno));
444        }
445    }
446    fclose(fp);
447    ifc_close();
448    return 0;
449}
450
451/*
452 * Return the address of the default gateway
453 *
454 * TODO: factor out common code from this and remove_host_routes()
455 * so that we only scan /proc/net/route in one place.
456 */
457int ifc_get_default_route(const char *ifname)
458{
459    char name[64];
460    in_addr_t dest, gway, mask;
461    int flags, refcnt, use, metric, mtu, win, irtt;
462    int result;
463    FILE *fp;
464
465    fp = fopen("/proc/net/route", "r");
466    if (fp == NULL)
467        return 0;
468    /* Skip the header line */
469    if (fscanf(fp, "%*[^\n]\n") < 0) {
470        fclose(fp);
471        return 0;
472    }
473    ifc_init();
474    result = 0;
475    for (;;) {
476        int nread = fscanf(fp, "%63s%X%X%X%d%d%d%X%d%d%d\n",
477                           name, &dest, &gway, &flags, &refcnt, &use, &metric, &mask,
478                           &mtu, &win, &irtt);
479        if (nread != 11) {
480            break;
481        }
482        if ((flags & (RTF_UP|RTF_GATEWAY)) == (RTF_UP|RTF_GATEWAY)
483                && dest == 0
484                && strcmp(ifname, name) == 0) {
485            result = gway;
486            break;
487        }
488    }
489    fclose(fp);
490    ifc_close();
491    return result;
492}
493
494/*
495 * Sets the specified gateway as the default route for the named interface.
496 */
497int ifc_set_default_route(const char *ifname, in_addr_t gateway)
498{
499    struct in_addr addr;
500    int result;
501
502    ifc_init();
503    addr.s_addr = gateway;
504    if ((result = ifc_create_default_route(ifname, gateway)) < 0) {
505        LOGD("failed to add %s as default route for %s: %s",
506             inet_ntoa(addr), ifname, strerror(errno));
507    }
508    ifc_close();
509    return result;
510}
511
512/*
513 * Removes the default route for the named interface.
514 */
515int ifc_remove_default_route(const char *ifname)
516{
517    struct rtentry rt;
518    int result;
519
520    ifc_init();
521    memset(&rt, 0, sizeof(rt));
522    rt.rt_dev = (void *)ifname;
523    rt.rt_flags = RTF_UP|RTF_GATEWAY;
524    init_sockaddr_in(&rt.rt_dst, 0);
525    if ((result = ioctl(ifc_ctl_sock, SIOCDELRT, &rt)) < 0) {
526        LOGD("failed to remove default route for %s: %s", ifname, strerror(errno));
527    }
528    ifc_close();
529    return result;
530}
531
532int
533ifc_configure(const char *ifname,
534        in_addr_t address,
535        uint32_t prefixLength,
536        in_addr_t gateway,
537        in_addr_t dns1,
538        in_addr_t dns2) {
539
540    char dns_prop_name[PROPERTY_KEY_MAX];
541
542    ifc_init();
543
544    if (ifc_up(ifname)) {
545        printerr("failed to turn on interface %s: %s\n", ifname, strerror(errno));
546        ifc_close();
547        return -1;
548    }
549    if (ifc_set_addr(ifname, address)) {
550        printerr("failed to set ipaddr %s: %s\n", ipaddr_to_string(address), strerror(errno));
551        ifc_close();
552        return -1;
553    }
554    if (ifc_set_prefixLength(ifname, prefixLength)) {
555        printerr("failed to set prefixLength %d: %s\n", prefixLength, strerror(errno));
556        ifc_close();
557        return -1;
558    }
559    if (ifc_create_default_route(ifname, gateway)) {
560        printerr("failed to set default route %s: %s\n", ipaddr_to_string(gateway), strerror(errno));
561        ifc_close();
562        return -1;
563    }
564
565    ifc_close();
566
567    snprintf(dns_prop_name, sizeof(dns_prop_name), "net.%s.dns1", ifname);
568    property_set(dns_prop_name, dns1 ? ipaddr_to_string(dns1) : "");
569    snprintf(dns_prop_name, sizeof(dns_prop_name), "net.%s.dns2", ifname);
570    property_set(dns_prop_name, dns2 ? ipaddr_to_string(dns2) : "");
571
572    return 0;
573}
574
575int ifc_add_ipv6_route(const char *ifname, struct in6_addr dst, int prefix_length,
576      struct in6_addr gw)
577{
578    struct in6_rtmsg rtmsg;
579    int result;
580    int ifindex;
581
582    memset(&rtmsg, 0, sizeof(rtmsg));
583
584    ifindex = if_nametoindex(ifname);
585    if (ifindex == 0) {
586        printerr("if_nametoindex() failed: interface %s\n", ifname);
587        return -ENXIO;
588    }
589
590    rtmsg.rtmsg_ifindex = ifindex;
591    rtmsg.rtmsg_dst = dst;
592    rtmsg.rtmsg_dst_len = prefix_length;
593    rtmsg.rtmsg_flags = RTF_UP;
594
595    if (prefix_length == 128) {
596        rtmsg.rtmsg_flags |= RTF_HOST;
597    }
598
599    if (memcmp(&gw, &in6addr_any, sizeof(in6addr_any))) {
600        rtmsg.rtmsg_flags |= RTF_GATEWAY;
601        rtmsg.rtmsg_gateway = gw;
602    }
603
604    ifc_init6();
605
606    if (ifc_ctl_sock6 < 0) {
607        return -errno;
608    }
609
610    result = ioctl(ifc_ctl_sock6, SIOCADDRT, &rtmsg);
611    if (result < 0) {
612        if (errno == EEXIST) {
613            result = 0;
614        } else {
615            result = -errno;
616        }
617    }
618    ifc_close6();
619    return result;
620}
621
622int ifc_add_route(const char *ifname, const char *dst, int prefix_length,
623      const char *gw)
624{
625    int ret = 0;
626    struct sockaddr_in ipv4_dst, ipv4_gw;
627    struct sockaddr_in6 ipv6_dst, ipv6_gw;
628    struct addrinfo hints, *addr_ai, *gw_ai;
629
630    memset(&hints, 0, sizeof(hints));
631    hints.ai_family = AF_UNSPEC;  /* Allow IPv4 or IPv6 */
632    hints.ai_flags = AI_NUMERICHOST;
633
634    ret = getaddrinfo(dst, NULL, &hints, &addr_ai);
635
636    if (ret != 0) {
637        printerr("getaddrinfo failed: invalid address %s\n", dst);
638        return -EINVAL;
639    }
640
641    if (gw == NULL) {
642        if (addr_ai->ai_family == AF_INET6) {
643            gw = "::";
644        } else if (addr_ai->ai_family == AF_INET) {
645            gw = "0.0.0.0";
646        }
647    }
648
649    ret = getaddrinfo(gw, NULL, &hints, &gw_ai);
650    if (ret != 0) {
651        printerr("getaddrinfo failed: invalid gateway %s\n", gw);
652        freeaddrinfo(addr_ai);
653        return -EINVAL;
654    }
655
656    if (addr_ai->ai_family != gw_ai->ai_family) {
657        printerr("ifc_add_route: different address families: %s and %s\n", dst, gw);
658        freeaddrinfo(addr_ai);
659        freeaddrinfo(gw_ai);
660        return -EINVAL;
661    }
662
663    if (addr_ai->ai_family == AF_INET6) {
664        memcpy(&ipv6_dst, addr_ai->ai_addr, sizeof(struct sockaddr_in6));
665        memcpy(&ipv6_gw, gw_ai->ai_addr, sizeof(struct sockaddr_in6));
666        ret = ifc_add_ipv6_route(ifname, ipv6_dst.sin6_addr, prefix_length,
667              ipv6_gw.sin6_addr);
668    } else if (addr_ai->ai_family == AF_INET) {
669        memcpy(&ipv4_dst, addr_ai->ai_addr, sizeof(struct sockaddr_in));
670        memcpy(&ipv4_gw, gw_ai->ai_addr, sizeof(struct sockaddr_in));
671        ret = ifc_add_ipv4_route(ifname, ipv4_dst.sin_addr, prefix_length,
672              ipv4_gw.sin_addr);
673    } else {
674        printerr("ifc_add_route: getaddrinfo returned un supported address family %d\n",
675                  addr_ai->ai_family);
676        ret = -EAFNOSUPPORT;
677    }
678
679    freeaddrinfo(addr_ai);
680    freeaddrinfo(gw_ai);
681    return ret;
682}
683