63 lines
2.1 KiB
C
63 lines
2.1 KiB
C
/*
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* Copyright (C) 2008 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <string.h>
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#include <unistd.h>
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#include <linux/sockios.h>
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#include <net/if.h>
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#include <sys/socket.h>
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#include <sys/ioctl.h>
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#include <errno.h>
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/*
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* Map an interface index into its name.
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* Returns NULL on error.
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*/
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char*
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if_indextoname(unsigned ifindex, char *ifname)
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{
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int index;
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int ctl_sock;
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struct ifreq ifr;
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char* ret = NULL;
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memset(&ifr, 0, sizeof(struct ifreq));
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ifr.ifr_ifindex = ifindex;
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if ((ctl_sock = socket(AF_INET, SOCK_DGRAM, 0)) >= 0) {
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if (ioctl(ctl_sock, SIOCGIFNAME, &ifr) >= 0) {
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ret = strncpy (ifname, ifr.ifr_name, IFNAMSIZ);
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} else {
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/* Posix requires ENXIO */
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if (errno == ENODEV)
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errno = ENXIO;
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}
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close(ctl_sock);
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}
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return ret;
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}
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