netaddress.h

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// Copyright (c) 2009-2020 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 <attributes.h>
#include <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>

static constexpr int ADDRV2_FORMAT = 0x20000000;

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 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};

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
        bool IsIPv4() const;    // IPv4 mapped address (::FFFF:0:0/96, 0.0.0.0/0)
        bool IsIPv6() const;    // 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)
        bool IsTor() const;
        bool IsI2P() const;
        bool IsCJDNS() const;
        bool IsLocal() const;
        bool IsRoutable() const;
        bool IsInternal() const;
        bool IsValid() const;

        bool IsAddrV1Compatible() const;

        enum Network GetNetwork() const;
        std::string ToString() const;
        std::string ToStringIP() const;
        uint64_t GetHash() const;
        bool GetInAddr(struct in_addr* pipv4Addr) const;
        Network GetNetClass() const;

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

        // The AS on the BGP path to the node we use to diversify
        // peers in AddrMan bucketing based on the AS infrastructure.
        // The ip->AS mapping depends on how asmap is constructed.
        uint32_t GetMappedAS(const std::vector<bool> &asmap) const;

        std::vector<unsigned char> GetGroup(const std::vector<bool> &asmap) const;
        std::vector<unsigned char> GetAddrBytes() const;
        int GetReachabilityFrom(const CNetAddr *paddrPartner = nullptr) 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();
        }

        template <typename Stream>
        void Serialize(Stream& s) const
        {
            if (s.GetVersion() & ADDRV2_FORMAT) {
                SerializeV2Stream(s);
            } else {
                SerializeV1Stream(s);
            }
        }

        template <typename Stream>
        void Unserialize(Stream& s)
        {
            if (s.GetVersion() & ADDRV2_FORMAT) {
                UnserializeV2Stream(s);
            } else {
                UnserializeV1Stream(s);
            }
        }

        friend class CNetAddrHash;
        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 >> MakeSpan(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 CNetAddrHash
{
public:
    size_t operator()(const CNetAddr& a) const noexcept
    {
        CSipHasher hasher(m_salt_k0, m_salt_k1);
        hasher.Write(a.m_net);
        hasher.Write(a.m_addr.data(), a.m_addr.size());
        return static_cast<size_t>(hasher.Finalize());
    }

private:
    const uint64_t m_salt_k0 = GetRand(std::numeric_limits<uint64_t>::max());
    const uint64_t m_salt_k1 = GetRand(std::numeric_limits<uint64_t>::max());
};

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

        bool SanityCheck() const;

    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);

        SERIALIZE_METHODS(CSubNet, obj)
        {
            READWRITE(obj.network);
            if (obj.network.IsIPv4()) {
                // Before commit 102867c587f5f7954232fb8ed8e85cda78bb4d32, CSubNet used the last 4 bytes of netmask
                // to store the relevant bytes for an IPv4 mask. For compatibility reasons, keep doing so in
                // serialized form.
                unsigned char dummy[12] = {0};
                READWRITE(dummy);
                READWRITE(MakeSpan(obj.netmask).first(4));
            } else {
                READWRITE(obj.netmask);
            }
            READWRITE(obj.valid);
            // Mark invalid if the result doesn't pass sanity checking.
            SER_READ(obj, if (obj.valid) obj.valid = obj.SanityCheck());
        }
};

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 ToString() const;
        std::string ToStringPort() const;
        std::string ToStringIPPort() const;

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

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

bool SanityCheckASMap(const std::vector<bool>& asmap);

#endif // BITCOIN_NETADDRESS_H