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Add asmap utility which queries a mapping
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The scripts for creating a compact IP->ASN mapping are here:
https://github.com/sipa/asmap

Co-authored-by: Pieter Wuille <pieter.wuille@gmail.com>
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2 people authored and furszy committed Jul 28, 2021
1 parent e986ed0 commit 8d01cbd
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1 change: 1 addition & 0 deletions CMakeLists.txt
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Expand Up @@ -427,6 +427,7 @@ set(UTIL_SOURCES
./src/threadinterrupt.cpp
./src/arith_uint256.cpp
./src/uint256.cpp
./src/util/asmap.cpp
./src/util/threadnames.cpp
./src/util/blockstatecatcher.h
./src/util/system.cpp
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2 changes: 2 additions & 0 deletions src/Makefile.am
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Expand Up @@ -293,6 +293,7 @@ BITCOIN_CORE_H = \
guiinterfaceutil.h \
uint256.h \
undo.h \
util/asmap.h \
util/blockstatecatcher.h \
util/system.h \
util/macros.h \
Expand Down Expand Up @@ -561,6 +562,7 @@ libbitcoin_util_a_SOURCES = \
support/lockedpool.cpp \
sync.cpp \
threadinterrupt.cpp \
util/asmap.cpp \
uint256.cpp \
util/system.cpp \
utilmoneystr.cpp \
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97 changes: 97 additions & 0 deletions src/util/asmap.cpp
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// Copyright (c) 2019 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <vector>
#include <assert.h>
#include <crypto/common.h>

namespace {

uint32_t DecodeBits(std::vector<bool>::const_iterator& bitpos, uint8_t minval, const std::vector<uint8_t> &bit_sizes)
{
uint32_t val = minval;
bool bit;
for (std::vector<uint8_t>::const_iterator bit_sizes_it = bit_sizes.begin();
bit_sizes_it != bit_sizes.end(); ++bit_sizes_it) {
if (bit_sizes_it + 1 != bit_sizes.end()) {
bit = *bitpos;
bitpos++;
} else {
bit = 0;
}
if (bit) {
val += (1 << *bit_sizes_it);
} else {
for (int b = 0; b < *bit_sizes_it; b++) {
bit = *bitpos;
bitpos++;
val += bit << (*bit_sizes_it - 1 - b);
}
return val;
}
}
return -1;
}

const std::vector<uint8_t> TYPE_BIT_SIZES{0, 0, 1};
uint32_t DecodeType(std::vector<bool>::const_iterator& bitpos)
{
return DecodeBits(bitpos, 0, TYPE_BIT_SIZES);
}

const std::vector<uint8_t> ASN_BIT_SIZES{15, 16, 17, 18, 19, 20, 21, 22, 23, 24};
uint32_t DecodeASN(std::vector<bool>::const_iterator& bitpos)
{
return DecodeBits(bitpos, 1, ASN_BIT_SIZES);
}


const std::vector<uint8_t> MATCH_BIT_SIZES{1, 2, 3, 4, 5, 6, 7, 8};
uint32_t DecodeMatch(std::vector<bool>::const_iterator& bitpos)
{
return DecodeBits(bitpos, 2, MATCH_BIT_SIZES);
}


const std::vector<uint8_t> JUMP_BIT_SIZES{5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30};
uint32_t DecodeJump(std::vector<bool>::const_iterator& bitpos)
{
return DecodeBits(bitpos, 17, JUMP_BIT_SIZES);
}

}

uint32_t Interpret(const std::vector<bool> &asmap, const std::vector<bool> &ip)
{
std::vector<bool>::const_iterator pos = asmap.begin();
uint8_t bits = ip.size();
uint8_t default_asn = 0;
uint32_t opcode, jump, match, matchlen;
while (1) {
assert(pos != asmap.end());
opcode = DecodeType(pos);
if (opcode == 0) {
return DecodeASN(pos);
} else if (opcode == 1) {
jump = DecodeJump(pos);
if (ip[ip.size() - bits]) {
pos += jump;
}
bits--;
} else if (opcode == 2) {
match = DecodeMatch(pos);
matchlen = CountBits(match) - 1;
for (uint32_t bit = 0; bit < matchlen; bit++) {
if ((ip[ip.size() - bits]) != ((match >> (matchlen - 1 - bit)) & 1)) {
return default_asn;
}
bits--;
}
} else if (opcode == 3) {
default_asn = DecodeASN(pos);
} else {
assert(0);
}
}
}
10 changes: 10 additions & 0 deletions src/util/asmap.h
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// Copyright (c) 2019 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef BITCOIN_UTIL_ASMAP_H
#define BITCOIN_UTIL_ASMAP_H

uint32_t Interpret(const std::vector<bool> &asmap, const std::vector<bool> &ip);

#endif // BITCOIN_UTIL_ASMAP_H

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