82 lines
2.2 KiB
C++
82 lines
2.2 KiB
C++
/*
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* Copyright 2016-2021 Max Kellermann <max.kellermann@gmail.com>
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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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*
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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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*
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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 the
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* 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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* FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "AddressInfo.hxx"
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#include "Features.hxx"
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#include <cassert>
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static constexpr int address_family_ranking[] = {
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#ifdef HAVE_UN
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AF_LOCAL,
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#endif
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AF_INET6,
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};
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static bool
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IsAddressFamilyBetter(int previous, int next)
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{
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for (auto i : address_family_ranking) {
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if (next == i)
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return previous != i;
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if (previous == i)
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return false;
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}
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return false;
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}
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static bool
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IsBetter(const AddressInfo &previous, const AddressInfo &next)
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{
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return IsAddressFamilyBetter(previous.GetFamily(),
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next.GetFamily());
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}
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static bool
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IsBetter(const AddressInfo *previous, const AddressInfo &next)
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{
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return previous == nullptr || IsBetter(*previous, next);
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}
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const AddressInfo &
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AddressInfoList::GetBest() const
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{
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assert(!empty());
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const AddressInfo *best = nullptr;
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for (const auto &i : *this)
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if (IsBetter(best, i))
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best = &i;
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assert(best != nullptr);
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return *best;
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}
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