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      1 /* external/dhcpcd/ifaddrs.c
      2 **
      3 ** Copyright 2011, The Android Open Source Project
      4 **
      5 ** Licensed under the Apache License, Version 2.0 (the "License");.
      6 ** you may not use this file except in compliance with the License..
      7 ** You may obtain a copy of the License at.
      8 **
      9 **     http://www.apache.org/licenses/LICENSE-2.0.
     10 **
     11 ** Unless required by applicable law or agreed to in writing, software.
     12 ** distributed under the License is distributed on an "AS IS" BASIS,.
     13 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied..
     14 ** See the License for the specific language governing permissions and.
     15 ** limitations under the License.
     16 */
     17 
     18 #include <arpa/inet.h>
     19 #include <sys/socket.h>
     20 #include "ifaddrs.h"
     21 #include <stdio.h>
     22 #include <stdlib.h>
     23 #include <unistd.h>
     24 #include <sys/types.h>
     25 #include <dirent.h>
     26 #include <netinet/ether.h>
     27 #include <netdb.h>
     28 #include <linux/if_packet.h>
     29 #include <netinet/if_ether.h>
     30 #include <linux/if_arp.h>
     31 #include <netutils/ifc.h>
     32 
     33 struct ifaddrs *get_interface(const char *name, sa_family_t family)
     34 {
     35     unsigned addr, flags;
     36     int masklen;
     37     struct ifaddrs *ifa;
     38     struct sockaddr_in *saddr = NULL;
     39     struct sockaddr_in *smask = NULL;
     40     struct sockaddr_ll *hwaddr = NULL;
     41     unsigned char hwbuf[ETH_ALEN];
     42 
     43     if (ifc_get_info(name, &addr, &masklen, &flags))
     44         return NULL;
     45 
     46     if ((family == AF_INET) && (addr == 0))
     47         return NULL;
     48 
     49     ifa = malloc(sizeof(struct ifaddrs));
     50     if (!ifa)
     51         return NULL;
     52     memset(ifa, 0, sizeof(struct ifaddrs));
     53 
     54     ifa->ifa_name = malloc(strlen(name)+1);
     55     if (!ifa->ifa_name) {
     56         free(ifa);
     57         return NULL;
     58     }
     59     strcpy(ifa->ifa_name, name);
     60     ifa->ifa_flags = flags;
     61 
     62     if (family == AF_INET) {
     63         saddr = malloc(sizeof(struct sockaddr_in));
     64         if (saddr) {
     65             saddr->sin_addr.s_addr = addr;
     66             saddr->sin_family = family;
     67         }
     68         ifa->ifa_addr = (struct sockaddr *)saddr;
     69 
     70         if (masklen != 0) {
     71             smask = malloc(sizeof(struct sockaddr_in));
     72             if (smask) {
     73                 smask->sin_addr.s_addr = prefixLengthToIpv4Netmask(masklen);
     74                 smask->sin_family = family;
     75             }
     76         }
     77         ifa->ifa_netmask = (struct sockaddr *)smask;
     78     } else if (family == AF_PACKET) {
     79         if (!ifc_get_hwaddr(name, hwbuf)) {
     80             hwaddr = malloc(sizeof(struct sockaddr_ll));
     81             if (hwaddr) {
     82                 memset(hwaddr, 0, sizeof(struct sockaddr_ll));
     83                 hwaddr->sll_family = family;
     84                 /* hwaddr->sll_protocol = ETHERTYPE_IP; */
     85                 hwaddr->sll_hatype = ARPHRD_ETHER;
     86                 hwaddr->sll_halen = ETH_ALEN;
     87                 memcpy(hwaddr->sll_addr, hwbuf, ETH_ALEN);
     88             }
     89         }
     90         ifa->ifa_addr = (struct sockaddr *)hwaddr;
     91         ifa->ifa_netmask = (struct sockaddr *)smask;
     92     }
     93     return ifa;
     94 }
     95 
     96 int getifaddrs(struct ifaddrs **ifap)
     97 {
     98     DIR *d;
     99     struct dirent *de;
    100     struct ifaddrs *ifa;
    101     struct ifaddrs *ifah = NULL;
    102 
    103     if (!ifap)
    104         return -1;
    105     *ifap = NULL;
    106 
    107     if (ifc_init())
    108        return -1;
    109 
    110     d = opendir("/sys/class/net");
    111     if (d == 0)
    112         return -1;
    113     while ((de = readdir(d))) {
    114         if (de->d_name[0] == '.')
    115             continue;
    116         ifa = get_interface(de->d_name, AF_INET);
    117         if (ifa != NULL) {
    118             ifa->ifa_next = ifah;
    119             ifah = ifa;
    120         }
    121         ifa = get_interface(de->d_name, AF_PACKET);
    122         if (ifa != NULL) {
    123             ifa->ifa_next = ifah;
    124             ifah = ifa;
    125         }
    126     }
    127     *ifap = ifah;
    128     closedir(d);
    129     ifc_close();
    130     return 0;
    131 }
    132 
    133 void freeifaddrs(struct ifaddrs *ifa)
    134 {
    135     struct ifaddrs *ifp;
    136 
    137     while (ifa) {
    138         ifp = ifa;
    139         free(ifp->ifa_name);
    140         if (ifp->ifa_addr)
    141             free(ifp->ifa_addr);
    142         if (ifp->ifa_netmask)
    143             free(ifp->ifa_netmask);
    144         ifa = ifa->ifa_next;
    145         free(ifp);
    146     }
    147 }
    148