netaddress.h

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// Copyright (c) 2009-2022 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_NETADDRESS_H
#define BITCOIN_NETADDRESS_H

#if defined(HAVE_CONFIG_H)
#include <config/bitcoin-config.h>
#endif

#include <compat/compat.h>
#include <crypto/siphash.h>
#include <prevector.h>
#include <random.h>
#include <serialize.h>
#include <tinyformat.h>
#include <util/strencodings.h>
#include <util/string.h>

#include <array>
#include <cstdint>
#include <ios>
#include <string>
#include <vector>

enum Network {
    NET_UNROUTABLE = 0,

    NET_IPV4,

    NET_IPV6,

    NET_ONION,

    NET_I2P,

    NET_CJDNS,

    NET_INTERNAL,

    NET_MAX,
};

static const std::array<uint8_t, 12> IPV4_IN_IPV6_PREFIX{
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF};

static const std::array<uint8_t, 6> TORV2_IN_IPV6_PREFIX{
    0xFD, 0x87, 0xD8, 0x7E, 0xEB, 0x43};

static const std::array<uint8_t, 6> INTERNAL_IN_IPV6_PREFIX{
    0xFD, 0x6B, 0x88, 0xC0, 0x87, 0x24 // 0xFD + sha256("bitcoin")[0:5].
};

static constexpr uint8_t CJDNS_PREFIX{0xFC};

static constexpr size_t ADDR_IPV4_SIZE = 4;

static constexpr size_t ADDR_IPV6_SIZE = 16;

static constexpr size_t ADDR_TORV3_SIZE = 32;

static constexpr size_t ADDR_I2P_SIZE = 32;

static constexpr size_t ADDR_CJDNS_SIZE = 16;

static constexpr size_t ADDR_INTERNAL_SIZE = 10;

static constexpr uint16_t I2P_SAM31_PORT{0};

std::string OnionToString(Span<const uint8_t> addr);

class CNetAddr
{
protected:
    prevector<ADDR_IPV6_SIZE, uint8_t> m_addr{ADDR_IPV6_SIZE, 0x0};

    Network m_net{NET_IPV6};

    uint32_t m_scope_id{0};

public:
    CNetAddr();
    explicit CNetAddr(const struct in_addr& ipv4Addr);
    void SetIP(const CNetAddr& ip);

    void SetLegacyIPv6(Span<const uint8_t> ipv6);

    bool SetInternal(const std::string& name);

    bool SetSpecial(const std::string& addr);

    bool IsBindAny() const; // INADDR_ANY equivalent
    [[nodiscard]] bool IsIPv4() const { return m_net == NET_IPV4; } // IPv4 mapped address (::FFFF:0:0/96, 0.0.0.0/0)
    [[nodiscard]] bool IsIPv6() const { return m_net == NET_IPV6; } // IPv6 address (not mapped IPv4, not Tor)
    bool IsRFC1918() const; // IPv4 private networks (10.0.0.0/8, 192.168.0.0/16, 172.16.0.0/12)
    bool IsRFC2544() const; // IPv4 inter-network communications (198.18.0.0/15)
    bool IsRFC6598() const; // IPv4 ISP-level NAT (100.64.0.0/10)
    bool IsRFC5737() const; // IPv4 documentation addresses (192.0.2.0/24, 198.51.100.0/24, 203.0.113.0/24)
    bool IsRFC3849() const; // IPv6 documentation address (2001:0DB8::/32)
    bool IsRFC3927() const; // IPv4 autoconfig (169.254.0.0/16)
    bool IsRFC3964() const; // IPv6 6to4 tunnelling (2002::/16)
    bool IsRFC4193() const; // IPv6 unique local (FC00::/7)
    bool IsRFC4380() const; // IPv6 Teredo tunnelling (2001::/32)
    bool IsRFC4843() const; // IPv6 ORCHID (deprecated) (2001:10::/28)
    bool IsRFC7343() const; // IPv6 ORCHIDv2 (2001:20::/28)
    bool IsRFC4862() const; // IPv6 autoconfig (FE80::/64)
    bool IsRFC6052() const; // IPv6 well-known prefix for IPv4-embedded address (64:FF9B::/96)
    bool IsRFC6145() const; // IPv6 IPv4-translated address (::FFFF:0:0:0/96) (actually defined in RFC2765)
    bool IsHeNet() const;   // IPv6 Hurricane Electric - https://he.net (2001:0470::/36)
    [[nodiscard]] bool IsTor() const { return m_net == NET_ONION; }
    [[nodiscard]] bool IsI2P() const { return m_net == NET_I2P; }
    [[nodiscard]] bool IsCJDNS() const { return m_net == NET_CJDNS; }
    [[nodiscard]] bool HasCJDNSPrefix() const { return m_addr[0] == CJDNS_PREFIX; }
    bool IsLocal() const;
    bool IsRoutable() const;
    bool IsInternal() const;
    bool IsValid() const;

    [[nodiscard]] bool IsPrivacyNet() const { return IsTor() || IsI2P(); }

    bool IsAddrV1Compatible() const;

    enum Network GetNetwork() const;
    std::string ToStringAddr() const;
    bool GetInAddr(struct in_addr* pipv4Addr) const;
    Network GetNetClass() const;

    uint32_t GetLinkedIPv4() const;
    bool HasLinkedIPv4() const;

    std::vector<unsigned char> GetAddrBytes() const;
    int GetReachabilityFrom(const CNetAddr& paddrPartner) const;

    explicit CNetAddr(const struct in6_addr& pipv6Addr, const uint32_t scope = 0);
    bool GetIn6Addr(struct in6_addr* pipv6Addr) const;

    friend bool operator==(const CNetAddr& a, const CNetAddr& b);
    friend bool operator!=(const CNetAddr& a, const CNetAddr& b) { return !(a == b); }
    friend bool operator<(const CNetAddr& a, const CNetAddr& b);

    bool IsRelayable() const
    {
        return IsIPv4() || IsIPv6() || IsTor() || IsI2P() || IsCJDNS();
    }

    enum class Encoding {
        V1,
        V2, 
    };
    struct SerParams {
        const Encoding enc;
        SER_PARAMS_OPFUNC
    };
    static constexpr SerParams V1{Encoding::V1};
    static constexpr SerParams V2{Encoding::V2};

    template <typename Stream>
    void Serialize(Stream& s) const
    {
        if (s.GetParams().enc == Encoding::V2) {
            SerializeV2Stream(s);
        } else {
            SerializeV1Stream(s);
        }
    }

    template <typename Stream>
    void Unserialize(Stream& s)
    {
        if (s.GetParams().enc == Encoding::V2) {
            UnserializeV2Stream(s);
        } else {
            UnserializeV1Stream(s);
        }
    }

    friend class CSubNet;

private:
    bool SetTor(const std::string& addr);

    bool SetI2P(const std::string& addr);

    enum BIP155Network : uint8_t {
        IPV4 = 1,
        IPV6 = 2,
        TORV2 = 3,
        TORV3 = 4,
        I2P = 5,
        CJDNS = 6,
    };

    static constexpr size_t V1_SERIALIZATION_SIZE = ADDR_IPV6_SIZE;

    static constexpr size_t MAX_ADDRV2_SIZE = 512;

    BIP155Network GetBIP155Network() const;

    bool SetNetFromBIP155Network(uint8_t possible_bip155_net, size_t address_size);

    void SerializeV1Array(uint8_t (&arr)[V1_SERIALIZATION_SIZE]) const
    {
        size_t prefix_size;

        switch (m_net) {
        case NET_IPV6:
            assert(m_addr.size() == sizeof(arr));
            memcpy(arr, m_addr.data(), m_addr.size());
            return;
        case NET_IPV4:
            prefix_size = sizeof(IPV4_IN_IPV6_PREFIX);
            assert(prefix_size + m_addr.size() == sizeof(arr));
            memcpy(arr, IPV4_IN_IPV6_PREFIX.data(), prefix_size);
            memcpy(arr + prefix_size, m_addr.data(), m_addr.size());
            return;
        case NET_INTERNAL:
            prefix_size = sizeof(INTERNAL_IN_IPV6_PREFIX);
            assert(prefix_size + m_addr.size() == sizeof(arr));
            memcpy(arr, INTERNAL_IN_IPV6_PREFIX.data(), prefix_size);
            memcpy(arr + prefix_size, m_addr.data(), m_addr.size());
            return;
        case NET_ONION:
        case NET_I2P:
        case NET_CJDNS:
            break;
        case NET_UNROUTABLE:
        case NET_MAX:
            assert(false);
        } // no default case, so the compiler can warn about missing cases

        // Serialize ONION, I2P and CJDNS as all-zeros.
        memset(arr, 0x0, V1_SERIALIZATION_SIZE);
    }

    template <typename Stream>
    void SerializeV1Stream(Stream& s) const
    {
        uint8_t serialized[V1_SERIALIZATION_SIZE];

        SerializeV1Array(serialized);

        s << serialized;
    }

    template <typename Stream>
    void SerializeV2Stream(Stream& s) const
    {
        if (IsInternal()) {
            // Serialize NET_INTERNAL as embedded in IPv6. We need to
            // serialize such addresses from addrman.
            s << static_cast<uint8_t>(BIP155Network::IPV6);
            s << COMPACTSIZE(ADDR_IPV6_SIZE);
            SerializeV1Stream(s);
            return;
        }

        s << static_cast<uint8_t>(GetBIP155Network());
        s << m_addr;
    }

    void UnserializeV1Array(uint8_t (&arr)[V1_SERIALIZATION_SIZE])
    {
        // Use SetLegacyIPv6() so that m_net is set correctly. For example
        // ::FFFF:0102:0304 should be set as m_net=NET_IPV4 (1.2.3.4).
        SetLegacyIPv6(arr);
    }

    template <typename Stream>
    void UnserializeV1Stream(Stream& s)
    {
        uint8_t serialized[V1_SERIALIZATION_SIZE];

        s >> serialized;

        UnserializeV1Array(serialized);
    }

    template <typename Stream>
    void UnserializeV2Stream(Stream& s)
    {
        uint8_t bip155_net;
        s >> bip155_net;

        size_t address_size;
        s >> COMPACTSIZE(address_size);

        if (address_size > MAX_ADDRV2_SIZE) {
            throw std::ios_base::failure(strprintf(
                "Address too long: %u > %u", address_size, MAX_ADDRV2_SIZE));
        }

        m_scope_id = 0;

        if (SetNetFromBIP155Network(bip155_net, address_size)) {
            m_addr.resize(address_size);
            s >> Span{m_addr};

            if (m_net != NET_IPV6) {
                return;
            }

            // Do some special checks on IPv6 addresses.

            // Recognize NET_INTERNAL embedded in IPv6, such addresses are not
            // gossiped but could be coming from addrman, when unserializing from
            // disk.
            if (HasPrefix(m_addr, INTERNAL_IN_IPV6_PREFIX)) {
                m_net = NET_INTERNAL;
                memmove(m_addr.data(), m_addr.data() + INTERNAL_IN_IPV6_PREFIX.size(),
                        ADDR_INTERNAL_SIZE);
                m_addr.resize(ADDR_INTERNAL_SIZE);
                return;
            }

            if (!HasPrefix(m_addr, IPV4_IN_IPV6_PREFIX) &&
                !HasPrefix(m_addr, TORV2_IN_IPV6_PREFIX)) {
                return;
            }

            // IPv4 and TORv2 are not supposed to be embedded in IPv6 (like in V1
            // encoding). Unserialize as !IsValid(), thus ignoring them.
        } else {
            // If we receive an unknown BIP155 network id (from the future?) then
            // ignore the address - unserialize as !IsValid().
            s.ignore(address_size);
        }

        // Mimic a default-constructed CNetAddr object which is !IsValid() and thus
        // will not be gossiped, but continue reading next addresses from the stream.
        m_net = NET_IPV6;
        m_addr.assign(ADDR_IPV6_SIZE, 0x0);
    }
};

class CSubNet
{
protected:
    CNetAddr network;
    uint8_t netmask[16];
    bool valid;

public:
    CSubNet();

    CSubNet(const CNetAddr& addr, uint8_t mask);

    CSubNet(const CNetAddr& addr, const CNetAddr& mask);

    explicit CSubNet(const CNetAddr& addr);

    bool Match(const CNetAddr& addr) const;

    std::string ToString() const;
    bool IsValid() const;

    friend bool operator==(const CSubNet& a, const CSubNet& b);
    friend bool operator!=(const CSubNet& a, const CSubNet& b) { return !(a == b); }
    friend bool operator<(const CSubNet& a, const CSubNet& b);
};

class CService : public CNetAddr
{
protected:
    uint16_t port; // host order

public:
    CService();
    CService(const CNetAddr& ip, uint16_t port);
    CService(const struct in_addr& ipv4Addr, uint16_t port);
    explicit CService(const struct sockaddr_in& addr);
    uint16_t GetPort() const;
    bool GetSockAddr(struct sockaddr* paddr, socklen_t* addrlen) const;
    bool SetSockAddr(const struct sockaddr* paddr);
    friend bool operator==(const CService& a, const CService& b);
    friend bool operator!=(const CService& a, const CService& b) { return !(a == b); }
    friend bool operator<(const CService& a, const CService& b);
    std::vector<unsigned char> GetKey() const;
    std::string ToStringAddrPort() const;

    CService(const struct in6_addr& ipv6Addr, uint16_t port);
    explicit CService(const struct sockaddr_in6& addr);

    SERIALIZE_METHODS(CService, obj)
    {
        READWRITE(AsBase<CNetAddr>(obj), Using<BigEndianFormatter<2>>(obj.port));
    }

    friend class CServiceHash;
    friend CService MaybeFlipIPv6toCJDNS(const CService& service);
};

class CServiceHash
{
public:
    CServiceHash()
        : m_salt_k0{GetRand<uint64_t>()},
          m_salt_k1{GetRand<uint64_t>()}
    {
    }

    CServiceHash(uint64_t salt_k0, uint64_t salt_k1) : m_salt_k0{salt_k0}, m_salt_k1{salt_k1} {}

    size_t operator()(const CService& a) const noexcept
    {
        CSipHasher hasher(m_salt_k0, m_salt_k1);
        hasher.Write(a.m_net);
        hasher.Write(a.port);
        hasher.Write(a.m_addr);
        return static_cast<size_t>(hasher.Finalize());
    }

private:
    const uint64_t m_salt_k0;
    const uint64_t m_salt_k1;
};

#endif // BITCOIN_NETADDRESS_H