transmission/libtransmission/blocklist.h

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// This file Copyright © 2008-2022 Mnemosyne LLC.
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// It may be used under GPLv2 (SPDX: GPL-2.0-only), GPLv3 (SPDX: GPL-3.0-only),
// or any future license endorsed by Mnemosyne LLC.
// License text can be found in the licenses/ folder.
#pragma once
#ifndef __TRANSMISSION__
#error only libtransmission should #include this header.
#endif
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#include <cstddef> // for size_t
#include <cstdint>
#include <cstring>
#include <memory>
#include <string>
#include <string_view>
#include <vector>
#ifdef _WIN32
#include <ws2tcpip.h>
#else
#include <netinet/in.h>
#endif
#include "file.h" // for tr_sys_file_t
#include "tr-assert.h"
#include "tr-macros.h"
struct tr_address;
struct BlocklistFile
{
public:
// Prevent moving to protect the fd_ from accidental destruction
BlocklistFile(BlocklistFile&&) = delete;
BlocklistFile(BlocklistFile const&) = delete;
BlocklistFile& operator=(BlocklistFile const&) = delete;
BlocklistFile& operator=(BlocklistFile&&) = delete;
BlocklistFile(char const* filename, bool isEnabled)
: filename_(filename)
, is_enabled_(isEnabled)
{
}
~BlocklistFile()
{
close();
}
[[nodiscard]] constexpr auto& filename() const
{
return filename_;
}
[[nodiscard]] bool exists() const
{
return tr_sys_path_exists(filename_.c_str(), nullptr);
}
[[nodiscard]] size_t getRuleCount() const
{
ensureLoaded();
return std::size(rules_);
}
[[nodiscard]] constexpr bool isEnabled() const
{
return is_enabled_;
}
void setEnabled(bool isEnabled)
{
is_enabled_ = isEnabled;
}
bool hasAddress(tr_address const& addr);
/// @brief Read the file of ranges, sort and merge, write to our own file, and reload from it
size_t setContent(char const* filename);
static std::vector<std::unique_ptr<BlocklistFile>> loadBlocklists(std::string_view const config_dir, bool const is_enabled);
private:
struct AddressRange
{
uint32_t begin_ = 0;
uint32_t end_ = 0;
in6_addr begin6_;
in6_addr end6_;
/// @brief Used for std::bsearch of an IPv4 address
static int compareIPv4AddressToRange(void const* va, void const* vb)
{
auto const* a = reinterpret_cast<uint32_t const*>(va);
auto const* b = reinterpret_cast<AddressRange const*>(vb);
if (*a < b->begin_)
{
return -1;
}
if (*a > b->end_)
{
return 1;
}
return 0;
}
/// @brief Used for std::bsearch of an IPv6 address
static int compareIPv6AddressToRange(void const* va, void const* vb)
{
auto const* a = reinterpret_cast<in6_addr const*>(va);
auto const* b = reinterpret_cast<AddressRange const*>(vb);
if (memcmp(&a->s6_addr, &b->begin6_.s6_addr, sizeof(a->s6_addr)) < 0)
{
return -1;
}
if (memcmp(&a->s6_addr, &b->end6_.s6_addr, sizeof(a->s6_addr)) > 0)
{
return 1;
}
return 0;
}
};
void RewriteBlocklistFile() const;
void ensureLoaded() const;
void load();
void close();
static bool parseLine(char const* line, AddressRange* range);
static bool compareAddressRangesByFirstAddress(AddressRange const& a, AddressRange const& b);
static bool parseLine1(std::string_view line, struct AddressRange* range);
static bool parseLine2(std::string_view line, struct AddressRange* range);
static bool parseLine3(char const* line, AddressRange* range);
#ifdef TR_ENABLE_ASSERTS
/// @brief Sanity checks: make sure the rules are sorted in ascending order and don't overlap
static void assertValidRules(std::vector<AddressRange> const& ranges);
#endif
std::string const filename_;
bool is_enabled_ = false;
mutable std::vector<AddressRange> rules_;
};