/* ifaddrs.h -- declarations for getting network interface addresses
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Copyright (C) 2002-2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#ifndef _IFADDRS_H
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#define _IFADDRS_H 1
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#include <features.h>
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#include <sys/socket.h>
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__BEGIN_DECLS
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/* The `getifaddrs' function generates a linked list of these structures.
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Each element of the list describes one network interface. */
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struct ifaddrs
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{
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struct ifaddrs *ifa_next; /* Pointer to the next structure. */
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char *ifa_name; /* Name of this network interface. */
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unsigned int ifa_flags; /* Flags as from SIOCGIFFLAGS ioctl. */
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struct sockaddr *ifa_addr; /* Network address of this interface. */
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struct sockaddr *ifa_netmask; /* Netmask of this interface. */
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union
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{
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/* At most one of the following two is valid. If the IFF_BROADCAST
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bit is set in `ifa_flags', then `ifa_broadaddr' is valid. If the
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IFF_POINTOPOINT bit is set, then `ifa_dstaddr' is valid.
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It is never the case that both these bits are set at once. */
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struct sockaddr *ifu_broadaddr; /* Broadcast address of this interface. */
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struct sockaddr *ifu_dstaddr; /* Point-to-point destination address. */
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} ifa_ifu;
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/* These very same macros are defined by <net/if.h> for `struct ifaddr'.
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So if they are defined already, the existing definitions will be fine. */
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# ifndef ifa_broadaddr
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# define ifa_broadaddr ifa_ifu.ifu_broadaddr
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# endif
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# ifndef ifa_dstaddr
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# define ifa_dstaddr ifa_ifu.ifu_dstaddr
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# endif
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void *ifa_data; /* Address-specific data (may be unused). */
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};
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/* Create a linked list of `struct ifaddrs' structures, one for each
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network interface on the host machine. If successful, store the
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list in *IFAP and return 0. On errors, return -1 and set `errno'.
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The storage returned in *IFAP is allocated dynamically and can
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only be properly freed by passing it to `freeifaddrs'. */
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extern int getifaddrs (struct ifaddrs **__ifap) __THROW;
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/* Reclaim the storage allocated by a previous `getifaddrs' call. */
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extern void freeifaddrs (struct ifaddrs *__ifa) __THROW;
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__END_DECLS
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#endif /* ifaddrs.h */
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