mirror of
https://github.com/RGBCube/serenity
synced 2025-05-16 20:15:07 +00:00
100 lines
2.5 KiB
C++
100 lines
2.5 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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* Copyright (c) 2021, Sergey Bugaev <bugaevc@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include "Name.h"
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#include <AK/Random.h>
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#include <AK/Stream.h>
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#include <AK/Vector.h>
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#include <ctype.h>
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namespace DNS {
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Name::Name(DeprecatedString const& name)
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{
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if (name.ends_with('.'))
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m_name = name.substring(0, name.length() - 1);
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else
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m_name = name;
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}
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Name Name::parse(ReadonlyBytes data, size_t& offset, size_t recursion_level)
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{
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if (recursion_level > 4)
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return {};
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StringBuilder builder;
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while (true) {
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if (offset >= data.size())
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return {};
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u8 b = data[offset++];
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if (b == '\0') {
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// This terminates the name.
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return builder.to_deprecated_string();
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} else if ((b & 0xc0) == 0xc0) {
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// The two bytes tell us the offset when to continue from.
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if (offset >= data.size())
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return {};
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size_t dummy = (b & 0x3f) << 8 | data[offset++];
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auto rest_of_name = parse(data, dummy, recursion_level + 1);
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builder.append(rest_of_name.as_string());
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return builder.to_deprecated_string();
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} else {
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// This is the length of a part.
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if (offset + b >= data.size())
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return {};
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builder.append({ data.offset_pointer(offset), b });
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builder.append('.');
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offset += b;
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}
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}
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}
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size_t Name::serialized_size() const
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{
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if (m_name.is_empty())
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return 1;
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return m_name.length() + 2;
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}
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void Name::randomize_case()
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{
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StringBuilder builder;
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for (char c : m_name) {
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// Randomize the 0x20 bit in every ASCII character.
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if (isalpha(c)) {
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if (get_random_uniform(2))
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c |= 0x20;
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else
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c &= ~0x20;
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}
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builder.append(c);
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}
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m_name = builder.to_deprecated_string();
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}
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ErrorOr<void> Name::write_to_stream(Stream& stream) const
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{
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auto parts = as_string().split_view('.');
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for (auto& part : parts) {
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TRY(stream.write_value<u8>(part.length()));
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TRY(stream.write_until_depleted(part.bytes()));
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}
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TRY(stream.write_value('\0'));
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return {};
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}
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unsigned Name::Traits::hash(Name const& name)
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{
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return CaseInsensitiveStringTraits::hash(name.as_string());
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}
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bool Name::Traits::equals(Name const& a, Name const& b)
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{
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return CaseInsensitiveStringTraits::equals(a.as_string(), b.as_string());
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}
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}
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