netaddress.h

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// Copyright (c) 2009-2016 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 <util/strencodings.h>
#include <util/string.h>
 
#include <tinyformat.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 + sha256("bitcoin")[0:5].
    {0xFD, 0x6B, 0x88, 0xC0, 0x87, 0x24}};
 
static constexpr size_t ADDR_IPV4_SIZE = 4;
 
static constexpr size_t ADDR_IPV6_SIZE = 16;
 
static constexpr size_t ADDR_TORV2_SIZE = 10;
 
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);
 
    // INADDR_ANY equivalent
    bool IsBindAny() const;
    // IPv4 mapped address (::FFFF:0:0/96, 0.0.0.0/0)
    bool IsIPv4() const;
    // IPv6 address (not mapped IPv4, not Tor)
    bool IsIPv6() const;
    // IPv4 private networks (10.0.0.0/8, 192.168.0.0/16, 172.16.0.0/12)
    bool IsRFC1918() const;
    // IPv4 inter-network communications (198.18.0.0/15)
    bool IsRFC2544() const;
    // IPv4 ISP-level NAT (100.64.0.0/10)
    bool IsRFC6598() const;
    // IPv4 documentation addresses (192.0.2.0/24, 198.51.100.0/24,
    // 203.0.113.0/24)
    bool IsRFC5737() const;
    // IPv6 documentation address (2001:0DB8::/32)
    bool IsRFC3849() const;
    // IPv4 autoconfig (169.254.0.0/16)
    bool IsRFC3927() const;
    // IPv6 6to4 tunnelling (2002::/16)
    bool IsRFC3964() const;
    // IPv6 unique local (FC00::/7)
    bool IsRFC4193() const;
    // IPv6 Teredo tunnelling (2001::/32)
    bool IsRFC4380() const;
    // IPv6 ORCHID (deprecated) (2001:10::/28)
    bool IsRFC4843() const;
    // IPv6 ORCHIDv2 (2001:20::/28)
    bool IsRFC7343() const;
    // IPv6 autoconfig (FE80::/64)
    bool IsRFC4862() const;
    // IPv6 well-known prefix for IPv4-embedded address (64:FF9B::/96)
    bool IsRFC6052() const;
    // IPv6 IPv4-translated address (::FFFF:0:0:0/96) (actually defined in
    // RFC2765)
    bool IsRFC6145() const;
    // IPv6 Hurricane Electric - https://he.net (2001:0470::/36)
    bool IsHeNet() const;
    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 ToStringAddr() 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<uint8_t> GetGroup(const std::vector<bool> &asmap) const;
    std::vector<uint8_t> 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(); }
 
    enum class Encoding {
        V1,
        V2,
    };
    struct SerParams {
        const Encoding enc;
    };
    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_ONION:
                if (m_addr.size() == ADDR_TORV3_SIZE) {
                    break;
                }
                prefix_size = sizeof(TORV2_IN_IPV6_PREFIX);
                assert(prefix_size + m_addr.size() == sizeof(arr));
                memcpy(arr, TORV2_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_I2P:
                break;
            case NET_CJDNS:
                break;
            case NET_UNROUTABLE:
            case NET_MAX:
                assert(false);
        } // no default case, so the compiler can warn about missing cases
 
        // Serialize TORv3, 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;
 
    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 D9176, CSubNet used the last 4 bytes of netmask to store
            // the relevant bytes for an IPv4 mask. For compatiblity reasons,
            // keep doing so in serialized form.
            uint8_t dummy[12] = {0};
            auto netmask_span = Span{obj.netmask};
            READWRITE(dummy);
            READWRITE(netmask_span.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:
    // host order
    uint16_t port;
 
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<uint8_t> 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;
};
 
class CServiceHash {
public:
    CServiceHash()
        : m_salt_k0{FastRandomContext().rand64()},
          m_salt_k1{FastRandomContext().rand64()} {}
 
    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