fuzz coverage

Coverage Report

Created: 2025-10-29 15:27

/Users/eugenesiegel/btc/bitcoin/src/netgroup.cpp
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// Copyright (c) 2021-2022 The Bitcoin Core developers
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// Distributed under the MIT software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#include <netgroup.h>
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#include <hash.h>
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#include <logging.h>
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#include <util/asmap.h>
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uint256 NetGroupManager::GetAsmapChecksum() const
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{
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    if (!m_asmap.size()) return {};
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    return (HashWriter{} << m_asmap).GetHash();
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}
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std::vector<unsigned char> NetGroupManager::GetGroup(const CNetAddr& address) const
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{
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    std::vector<unsigned char> vchRet;
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    // If non-empty asmap is supplied and the address is IPv4/IPv6,
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    // return ASN to be used for bucketing.
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    uint32_t asn = GetMappedAS(address);
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    if (asn != 0) { // Either asmap was empty, or address has non-asmappable net class (e.g. TOR).
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        vchRet.push_back(NET_IPV6); // IPv4 and IPv6 with same ASN should be in the same bucket
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        for (int i = 0; i < 4; i++) {
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            vchRet.push_back((asn >> (8 * i)) & 0xFF);
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        }
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        return vchRet;
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    }
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    vchRet.push_back(address.GetNetClass());
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    int nStartByte{0};
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    int nBits{0};
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    if (address.IsLocal()) {
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        // all local addresses belong to the same group
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    } else if (address.IsInternal()) {
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        // All internal-usage addresses get their own group.
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        // Skip over the INTERNAL_IN_IPV6_PREFIX returned by CAddress::GetAddrBytes().
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        nStartByte = INTERNAL_IN_IPV6_PREFIX.size();
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        nBits = ADDR_INTERNAL_SIZE * 8;
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    } else if (!address.IsRoutable()) {
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        // all other unroutable addresses belong to the same group
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    } else if (address.HasLinkedIPv4()) {
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        // IPv4 addresses (and mapped IPv4 addresses) use /16 groups
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        uint32_t ipv4 = address.GetLinkedIPv4();
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        vchRet.push_back((ipv4 >> 24) & 0xFF);
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        vchRet.push_back((ipv4 >> 16) & 0xFF);
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        return vchRet;
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    } else if (address.IsTor() || address.IsI2P()) {
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        nBits = 4;
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    } else if (address.IsCJDNS()) {
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        // Treat in the same way as Tor and I2P because the address in all of
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        // them is "random" bytes (derived from a public key). However in CJDNS
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        // the first byte is a constant (see CJDNS_PREFIX), so the random bytes
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        // come after it. Thus skip the constant 8 bits at the start.
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        nBits = 12;
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    } else if (address.IsHeNet()) {
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        // for he.net, use /36 groups
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        nBits = 36;
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    } else {
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        // for the rest of the IPv6 network, use /32 groups
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        nBits = 32;
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    }
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    // Push our address onto vchRet.
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    auto addr_bytes = address.GetAddrBytes();
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    const size_t num_bytes = nBits / 8;
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    vchRet.insert(vchRet.end(), addr_bytes.begin() + nStartByte, addr_bytes.begin() + nStartByte + num_bytes);
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    nBits %= 8;
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    // ...for the last byte, push nBits and for the rest of the byte push 1's
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    if (nBits > 0) {
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        assert(num_bytes < addr_bytes.size());
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        vchRet.push_back(addr_bytes[num_bytes + nStartByte] | ((1 << (8 - nBits)) - 1));
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    }
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    return vchRet;
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}
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uint32_t NetGroupManager::GetMappedAS(const CNetAddr& address) const
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{
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    uint32_t net_class = address.GetNetClass();
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    if (m_asmap.size() == 0 || 
(0
net_class != NET_IPV40
 && 
net_class != NET_IPV60
)) {
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        return 0; // Indicates not found, safe because AS0 is reserved per RFC7607.
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    }
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    std::vector<bool> ip_bits(128);
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    if (address.HasLinkedIPv4()) {
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        // For lookup, treat as if it was just an IPv4 address (IPV4_IN_IPV6_PREFIX + IPv4 bits)
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        for (int8_t byte_i = 0; byte_i < 12; ++byte_i) {
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            for (uint8_t bit_i = 0; bit_i < 8; ++bit_i) {
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                ip_bits[byte_i * 8 + bit_i] = (IPV4_IN_IPV6_PREFIX[byte_i] >> (7 - bit_i)) & 1;
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            }
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        }
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        uint32_t ipv4 = address.GetLinkedIPv4();
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        for (int i = 0; i < 32; ++i) {
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            ip_bits[96 + i] = (ipv4 >> (31 - i)) & 1;
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        }
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    } else {
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        // Use all 128 bits of the IPv6 address otherwise
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        assert(address.IsIPv6());
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        auto addr_bytes = address.GetAddrBytes();
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        for (int8_t byte_i = 0; byte_i < 16; ++byte_i) {
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            uint8_t cur_byte = addr_bytes[byte_i];
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            for (uint8_t bit_i = 0; bit_i < 8; ++bit_i) {
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                ip_bits[byte_i * 8 + bit_i] = (cur_byte >> (7 - bit_i)) & 1;
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            }
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        }
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    }
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    uint32_t mapped_as = Interpret(m_asmap, ip_bits);
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    return mapped_as;
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}
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void NetGroupManager::ASMapHealthCheck(const std::vector<CNetAddr>& clearnet_addrs) const {
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    std::set<uint32_t> clearnet_asns{};
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    int unmapped_count{0};
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    for (const auto& addr : clearnet_addrs) {
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        uint32_t asn = GetMappedAS(addr);
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        if (asn == 0) {
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            ++unmapped_count;
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            continue;
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        }
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        clearnet_asns.insert(asn);
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    }
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    LogPrintf("ASMap Health Check: %i clearnet peers are mapped to %i ASNs with %i peers being unmapped\n", clearnet_addrs.size(), clearnet_asns.size(), unmapped_count);
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#define LogPrintf(...) LogInfo(__VA_ARGS__)
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#define LogInfo(...) LogPrintLevel_(BCLog::LogFlags::ALL, BCLog::Level::Info, /*should_ratelimit=*/true, __VA_ARGS__)
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#define LogPrintLevel_(category, level, should_ratelimit, ...) LogPrintFormatInternal(std::source_location::current(), category, level, should_ratelimit, __VA_ARGS__)
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}
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bool NetGroupManager::UsingASMap() const {
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    return m_asmap.size() > 0;
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}