/ src / netaddress.cpp
netaddress.cpp
   1  // Copyright (c) 2009-2010 Satoshi Nakamoto
   2  // Copyright (c) 2009-2022 The Bitcoin Core developers
   3  // Distributed under the MIT software license, see the accompanying
   4  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
   5  
   6  #include <netaddress.h>
   7  
   8  #include <crypto/common.h>
   9  #include <crypto/sha3.h>
  10  #include <hash.h>
  11  #include <prevector.h>
  12  #include <tinyformat.h>
  13  #include <util/strencodings.h>
  14  #include <util/string.h>
  15  
  16  #include <algorithm>
  17  #include <array>
  18  #include <cstdint>
  19  #include <ios>
  20  #include <iterator>
  21  #include <tuple>
  22  
  23  CNetAddr::BIP155Network CNetAddr::GetBIP155Network() const
  24  {
  25      switch (m_net) {
  26      case NET_IPV4:
  27          return BIP155Network::IPV4;
  28      case NET_IPV6:
  29          return BIP155Network::IPV6;
  30      case NET_ONION:
  31          return BIP155Network::TORV3;
  32      case NET_I2P:
  33          return BIP155Network::I2P;
  34      case NET_CJDNS:
  35          return BIP155Network::CJDNS;
  36      case NET_INTERNAL:   // should have been handled before calling this function
  37      case NET_UNROUTABLE: // m_net is never and should not be set to NET_UNROUTABLE
  38      case NET_MAX:        // m_net is never and should not be set to NET_MAX
  39          assert(false);
  40      } // no default case, so the compiler can warn about missing cases
  41  
  42      assert(false);
  43  }
  44  
  45  bool CNetAddr::SetNetFromBIP155Network(uint8_t possible_bip155_net, size_t address_size)
  46  {
  47      switch (possible_bip155_net) {
  48      case BIP155Network::IPV4:
  49          if (address_size == ADDR_IPV4_SIZE) {
  50              m_net = NET_IPV4;
  51              return true;
  52          }
  53          throw std::ios_base::failure(
  54              strprintf("BIP155 IPv4 address with length %u (should be %u)", address_size,
  55                        ADDR_IPV4_SIZE));
  56      case BIP155Network::IPV6:
  57          if (address_size == ADDR_IPV6_SIZE) {
  58              m_net = NET_IPV6;
  59              return true;
  60          }
  61          throw std::ios_base::failure(
  62              strprintf("BIP155 IPv6 address with length %u (should be %u)", address_size,
  63                        ADDR_IPV6_SIZE));
  64      case BIP155Network::TORV3:
  65          if (address_size == ADDR_TORV3_SIZE) {
  66              m_net = NET_ONION;
  67              return true;
  68          }
  69          throw std::ios_base::failure(
  70              strprintf("BIP155 TORv3 address with length %u (should be %u)", address_size,
  71                        ADDR_TORV3_SIZE));
  72      case BIP155Network::I2P:
  73          if (address_size == ADDR_I2P_SIZE) {
  74              m_net = NET_I2P;
  75              return true;
  76          }
  77          throw std::ios_base::failure(
  78              strprintf("BIP155 I2P address with length %u (should be %u)", address_size,
  79                        ADDR_I2P_SIZE));
  80      case BIP155Network::CJDNS:
  81          if (address_size == ADDR_CJDNS_SIZE) {
  82              m_net = NET_CJDNS;
  83              return true;
  84          }
  85          throw std::ios_base::failure(
  86              strprintf("BIP155 CJDNS address with length %u (should be %u)", address_size,
  87                        ADDR_CJDNS_SIZE));
  88      }
  89  
  90      // Don't throw on addresses with unknown network ids (maybe from the future).
  91      // Instead silently drop them and have the unserialization code consume
  92      // subsequent ones which may be known to us.
  93      return false;
  94  }
  95  
  96  /**
  97   * Construct an unspecified IPv6 network address (::/128).
  98   *
  99   * @note This address is considered invalid by CNetAddr::IsValid()
 100   */
 101  CNetAddr::CNetAddr() = default;
 102  
 103  void CNetAddr::SetIP(const CNetAddr& ipIn)
 104  {
 105      // Size check.
 106      switch (ipIn.m_net) {
 107      case NET_IPV4:
 108          assert(ipIn.m_addr.size() == ADDR_IPV4_SIZE);
 109          break;
 110      case NET_IPV6:
 111          assert(ipIn.m_addr.size() == ADDR_IPV6_SIZE);
 112          break;
 113      case NET_ONION:
 114          assert(ipIn.m_addr.size() == ADDR_TORV3_SIZE);
 115          break;
 116      case NET_I2P:
 117          assert(ipIn.m_addr.size() == ADDR_I2P_SIZE);
 118          break;
 119      case NET_CJDNS:
 120          assert(ipIn.m_addr.size() == ADDR_CJDNS_SIZE);
 121          break;
 122      case NET_INTERNAL:
 123          assert(ipIn.m_addr.size() == ADDR_INTERNAL_SIZE);
 124          break;
 125      case NET_UNROUTABLE:
 126      case NET_MAX:
 127          assert(false);
 128      } // no default case, so the compiler can warn about missing cases
 129  
 130      m_net = ipIn.m_net;
 131      m_addr = ipIn.m_addr;
 132  }
 133  
 134  void CNetAddr::SetLegacyIPv6(Span<const uint8_t> ipv6)
 135  {
 136      assert(ipv6.size() == ADDR_IPV6_SIZE);
 137  
 138      size_t skip{0};
 139  
 140      if (HasPrefix(ipv6, IPV4_IN_IPV6_PREFIX)) {
 141          // IPv4-in-IPv6
 142          m_net = NET_IPV4;
 143          skip = sizeof(IPV4_IN_IPV6_PREFIX);
 144      } else if (HasPrefix(ipv6, TORV2_IN_IPV6_PREFIX)) {
 145          // TORv2-in-IPv6 (unsupported). Unserialize as !IsValid(), thus ignoring them.
 146          // Mimic a default-constructed CNetAddr object which is !IsValid() and thus
 147          // will not be gossiped, but continue reading next addresses from the stream.
 148          m_net = NET_IPV6;
 149          m_addr.assign(ADDR_IPV6_SIZE, 0x0);
 150          return;
 151      } else if (HasPrefix(ipv6, INTERNAL_IN_IPV6_PREFIX)) {
 152          // Internal-in-IPv6
 153          m_net = NET_INTERNAL;
 154          skip = sizeof(INTERNAL_IN_IPV6_PREFIX);
 155      } else {
 156          // IPv6
 157          m_net = NET_IPV6;
 158      }
 159  
 160      m_addr.assign(ipv6.begin() + skip, ipv6.end());
 161  }
 162  
 163  /**
 164   * Create an "internal" address that represents a name or FQDN. AddrMan uses
 165   * these fake addresses to keep track of which DNS seeds were used.
 166   * @returns Whether or not the operation was successful.
 167   * @see NET_INTERNAL, INTERNAL_IN_IPV6_PREFIX, CNetAddr::IsInternal(), CNetAddr::IsRFC4193()
 168   */
 169  bool CNetAddr::SetInternal(const std::string &name)
 170  {
 171      if (name.empty()) {
 172          return false;
 173      }
 174      m_net = NET_INTERNAL;
 175      unsigned char hash[32] = {};
 176      CSHA256().Write((const unsigned char*)name.data(), name.size()).Finalize(hash);
 177      m_addr.assign(hash, hash + ADDR_INTERNAL_SIZE);
 178      return true;
 179  }
 180  
 181  namespace torv3 {
 182  // https://gitweb.torproject.org/torspec.git/tree/rend-spec-v3.txt?id=7116c9cdaba248aae07a3f1d0e15d9dd102f62c5#n2175
 183  static constexpr size_t CHECKSUM_LEN = 2;
 184  static const unsigned char VERSION[] = {3};
 185  static constexpr size_t TOTAL_LEN = ADDR_TORV3_SIZE + CHECKSUM_LEN + sizeof(VERSION);
 186  
 187  static void Checksum(Span<const uint8_t> addr_pubkey, uint8_t (&checksum)[CHECKSUM_LEN])
 188  {
 189      // TORv3 CHECKSUM = H(".onion checksum" | PUBKEY | VERSION)[:2]
 190      static const unsigned char prefix[] = ".onion checksum";
 191      static constexpr size_t prefix_len = 15;
 192  
 193      SHA3_256 hasher;
 194  
 195      hasher.Write(Span{prefix}.first(prefix_len));
 196      hasher.Write(addr_pubkey);
 197      hasher.Write(VERSION);
 198  
 199      uint8_t checksum_full[SHA3_256::OUTPUT_SIZE];
 200  
 201      hasher.Finalize(checksum_full);
 202  
 203      memcpy(checksum, checksum_full, sizeof(checksum));
 204  }
 205  
 206  }; // namespace torv3
 207  
 208  bool CNetAddr::SetSpecial(const std::string& addr)
 209  {
 210      if (!ContainsNoNUL(addr)) {
 211          return false;
 212      }
 213  
 214      if (SetTor(addr)) {
 215          return true;
 216      }
 217  
 218      if (SetI2P(addr)) {
 219          return true;
 220      }
 221  
 222      return false;
 223  }
 224  
 225  bool CNetAddr::SetTor(const std::string& addr)
 226  {
 227      static const char* suffix{".onion"};
 228      static constexpr size_t suffix_len{6};
 229  
 230      if (addr.size() <= suffix_len || addr.substr(addr.size() - suffix_len) != suffix) {
 231          return false;
 232      }
 233  
 234      auto input = DecodeBase32(std::string_view{addr}.substr(0, addr.size() - suffix_len));
 235  
 236      if (!input) {
 237          return false;
 238      }
 239  
 240      if (input->size() == torv3::TOTAL_LEN) {
 241          Span<const uint8_t> input_pubkey{input->data(), ADDR_TORV3_SIZE};
 242          Span<const uint8_t> input_checksum{input->data() + ADDR_TORV3_SIZE, torv3::CHECKSUM_LEN};
 243          Span<const uint8_t> input_version{input->data() + ADDR_TORV3_SIZE + torv3::CHECKSUM_LEN, sizeof(torv3::VERSION)};
 244  
 245          if (input_version != torv3::VERSION) {
 246              return false;
 247          }
 248  
 249          uint8_t calculated_checksum[torv3::CHECKSUM_LEN];
 250          torv3::Checksum(input_pubkey, calculated_checksum);
 251  
 252          if (input_checksum != calculated_checksum) {
 253              return false;
 254          }
 255  
 256          m_net = NET_ONION;
 257          m_addr.assign(input_pubkey.begin(), input_pubkey.end());
 258          return true;
 259      }
 260  
 261      return false;
 262  }
 263  
 264  bool CNetAddr::SetI2P(const std::string& addr)
 265  {
 266      // I2P addresses that we support consist of 52 base32 characters + ".b32.i2p".
 267      static constexpr size_t b32_len{52};
 268      static const char* suffix{".b32.i2p"};
 269      static constexpr size_t suffix_len{8};
 270  
 271      if (addr.size() != b32_len + suffix_len || ToLower(addr.substr(b32_len)) != suffix) {
 272          return false;
 273      }
 274  
 275      // Remove the ".b32.i2p" suffix and pad to a multiple of 8 chars, so DecodeBase32()
 276      // can decode it.
 277      const std::string b32_padded = addr.substr(0, b32_len) + "====";
 278  
 279      auto address_bytes = DecodeBase32(b32_padded);
 280  
 281      if (!address_bytes || address_bytes->size() != ADDR_I2P_SIZE) {
 282          return false;
 283      }
 284  
 285      m_net = NET_I2P;
 286      m_addr.assign(address_bytes->begin(), address_bytes->end());
 287  
 288      return true;
 289  }
 290  
 291  CNetAddr::CNetAddr(const struct in_addr& ipv4Addr)
 292  {
 293      m_net = NET_IPV4;
 294      const uint8_t* ptr = reinterpret_cast<const uint8_t*>(&ipv4Addr);
 295      m_addr.assign(ptr, ptr + ADDR_IPV4_SIZE);
 296  }
 297  
 298  CNetAddr::CNetAddr(const struct in6_addr& ipv6Addr, const uint32_t scope)
 299  {
 300      SetLegacyIPv6({reinterpret_cast<const uint8_t*>(&ipv6Addr), sizeof(ipv6Addr)});
 301      m_scope_id = scope;
 302  }
 303  
 304  bool CNetAddr::IsBindAny() const
 305  {
 306      if (!IsIPv4() && !IsIPv6()) {
 307          return false;
 308      }
 309      return std::all_of(m_addr.begin(), m_addr.end(), [](uint8_t b) { return b == 0; });
 310  }
 311  
 312  bool CNetAddr::IsRFC1918() const
 313  {
 314      return IsIPv4() && (
 315          m_addr[0] == 10 ||
 316          (m_addr[0] == 192 && m_addr[1] == 168) ||
 317          (m_addr[0] == 172 && m_addr[1] >= 16 && m_addr[1] <= 31));
 318  }
 319  
 320  bool CNetAddr::IsRFC2544() const
 321  {
 322      return IsIPv4() && m_addr[0] == 198 && (m_addr[1] == 18 || m_addr[1] == 19);
 323  }
 324  
 325  bool CNetAddr::IsRFC3927() const
 326  {
 327      return IsIPv4() && HasPrefix(m_addr, std::array<uint8_t, 2>{169, 254});
 328  }
 329  
 330  bool CNetAddr::IsRFC6598() const
 331  {
 332      return IsIPv4() && m_addr[0] == 100 && m_addr[1] >= 64 && m_addr[1] <= 127;
 333  }
 334  
 335  bool CNetAddr::IsRFC5737() const
 336  {
 337      return IsIPv4() && (HasPrefix(m_addr, std::array<uint8_t, 3>{192, 0, 2}) ||
 338                          HasPrefix(m_addr, std::array<uint8_t, 3>{198, 51, 100}) ||
 339                          HasPrefix(m_addr, std::array<uint8_t, 3>{203, 0, 113}));
 340  }
 341  
 342  bool CNetAddr::IsRFC3849() const
 343  {
 344      return IsIPv6() && HasPrefix(m_addr, std::array<uint8_t, 4>{0x20, 0x01, 0x0D, 0xB8});
 345  }
 346  
 347  bool CNetAddr::IsRFC3964() const
 348  {
 349      return IsIPv6() && HasPrefix(m_addr, std::array<uint8_t, 2>{0x20, 0x02});
 350  }
 351  
 352  bool CNetAddr::IsRFC6052() const
 353  {
 354      return IsIPv6() &&
 355             HasPrefix(m_addr, std::array<uint8_t, 12>{0x00, 0x64, 0xFF, 0x9B, 0x00, 0x00,
 356                                                       0x00, 0x00, 0x00, 0x00, 0x00, 0x00});
 357  }
 358  
 359  bool CNetAddr::IsRFC4380() const
 360  {
 361      return IsIPv6() && HasPrefix(m_addr, std::array<uint8_t, 4>{0x20, 0x01, 0x00, 0x00});
 362  }
 363  
 364  bool CNetAddr::IsRFC4862() const
 365  {
 366      return IsIPv6() && HasPrefix(m_addr, std::array<uint8_t, 8>{0xFE, 0x80, 0x00, 0x00,
 367                                                                  0x00, 0x00, 0x00, 0x00});
 368  }
 369  
 370  bool CNetAddr::IsRFC4193() const
 371  {
 372      return IsIPv6() && (m_addr[0] & 0xFE) == 0xFC;
 373  }
 374  
 375  bool CNetAddr::IsRFC6145() const
 376  {
 377      return IsIPv6() &&
 378             HasPrefix(m_addr, std::array<uint8_t, 12>{0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 379                                                       0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00});
 380  }
 381  
 382  bool CNetAddr::IsRFC4843() const
 383  {
 384      return IsIPv6() && HasPrefix(m_addr, std::array<uint8_t, 3>{0x20, 0x01, 0x00}) &&
 385             (m_addr[3] & 0xF0) == 0x10;
 386  }
 387  
 388  bool CNetAddr::IsRFC7343() const
 389  {
 390      return IsIPv6() && HasPrefix(m_addr, std::array<uint8_t, 3>{0x20, 0x01, 0x00}) &&
 391             (m_addr[3] & 0xF0) == 0x20;
 392  }
 393  
 394  bool CNetAddr::IsHeNet() const
 395  {
 396      return IsIPv6() && HasPrefix(m_addr, std::array<uint8_t, 4>{0x20, 0x01, 0x04, 0x70});
 397  }
 398  
 399  bool CNetAddr::IsLocal() const
 400  {
 401      // IPv4 loopback (127.0.0.0/8 or 0.0.0.0/8)
 402      if (IsIPv4() && (m_addr[0] == 127 || m_addr[0] == 0)) {
 403          return true;
 404      }
 405  
 406      // IPv6 loopback (::1/128)
 407      static const unsigned char pchLocal[16] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
 408      if (IsIPv6() && memcmp(m_addr.data(), pchLocal, sizeof(pchLocal)) == 0) {
 409          return true;
 410      }
 411  
 412      return false;
 413  }
 414  
 415  /**
 416   * @returns Whether or not this network address is a valid address that @a could
 417   *          be used to refer to an actual host.
 418   *
 419   * @note A valid address may or may not be publicly routable on the global
 420   *       internet. As in, the set of valid addresses is a superset of the set of
 421   *       publicly routable addresses.
 422   *
 423   * @see CNetAddr::IsRoutable()
 424   */
 425  bool CNetAddr::IsValid() const
 426  {
 427      // unspecified IPv6 address (::/128)
 428      unsigned char ipNone6[16] = {};
 429      if (IsIPv6() && memcmp(m_addr.data(), ipNone6, sizeof(ipNone6)) == 0) {
 430          return false;
 431      }
 432  
 433      if (IsCJDNS() && !HasCJDNSPrefix()) {
 434          return false;
 435      }
 436  
 437      // documentation IPv6 address
 438      if (IsRFC3849())
 439          return false;
 440  
 441      if (IsInternal())
 442          return false;
 443  
 444      if (IsIPv4()) {
 445          const uint32_t addr = ReadBE32(m_addr.data());
 446          if (addr == INADDR_ANY || addr == INADDR_NONE) {
 447              return false;
 448          }
 449      }
 450  
 451      return true;
 452  }
 453  
 454  /**
 455   * @returns Whether or not this network address is publicly routable on the
 456   *          global internet.
 457   *
 458   * @note A routable address is always valid. As in, the set of routable addresses
 459   *       is a subset of the set of valid addresses.
 460   *
 461   * @see CNetAddr::IsValid()
 462   */
 463  bool CNetAddr::IsRoutable() const
 464  {
 465      return IsValid() && !(IsRFC1918() || IsRFC2544() || IsRFC3927() || IsRFC4862() || IsRFC6598() || IsRFC5737() || IsRFC4193() || IsRFC4843() || IsRFC7343() || IsLocal() || IsInternal());
 466  }
 467  
 468  /**
 469   * @returns Whether or not this is a dummy address that represents a name.
 470   *
 471   * @see CNetAddr::SetInternal(const std::string &)
 472   */
 473  bool CNetAddr::IsInternal() const
 474  {
 475     return m_net == NET_INTERNAL;
 476  }
 477  
 478  bool CNetAddr::IsAddrV1Compatible() const
 479  {
 480      switch (m_net) {
 481      case NET_IPV4:
 482      case NET_IPV6:
 483      case NET_INTERNAL:
 484          return true;
 485      case NET_ONION:
 486      case NET_I2P:
 487      case NET_CJDNS:
 488          return false;
 489      case NET_UNROUTABLE: // m_net is never and should not be set to NET_UNROUTABLE
 490      case NET_MAX:        // m_net is never and should not be set to NET_MAX
 491          assert(false);
 492      } // no default case, so the compiler can warn about missing cases
 493  
 494      assert(false);
 495  }
 496  
 497  enum Network CNetAddr::GetNetwork() const
 498  {
 499      if (IsInternal())
 500          return NET_INTERNAL;
 501  
 502      if (!IsRoutable())
 503          return NET_UNROUTABLE;
 504  
 505      return m_net;
 506  }
 507  
 508  static std::string IPv4ToString(Span<const uint8_t> a)
 509  {
 510      return strprintf("%u.%u.%u.%u", a[0], a[1], a[2], a[3]);
 511  }
 512  
 513  // Return an IPv6 address text representation with zero compression as described in RFC 5952
 514  // ("A Recommendation for IPv6 Address Text Representation").
 515  static std::string IPv6ToString(Span<const uint8_t> a, uint32_t scope_id)
 516  {
 517      assert(a.size() == ADDR_IPV6_SIZE);
 518      const std::array groups{
 519          ReadBE16(&a[0]),
 520          ReadBE16(&a[2]),
 521          ReadBE16(&a[4]),
 522          ReadBE16(&a[6]),
 523          ReadBE16(&a[8]),
 524          ReadBE16(&a[10]),
 525          ReadBE16(&a[12]),
 526          ReadBE16(&a[14]),
 527      };
 528  
 529      // The zero compression implementation is inspired by Rust's std::net::Ipv6Addr, see
 530      // https://github.com/rust-lang/rust/blob/cc4103089f40a163f6d143f06359cba7043da29b/library/std/src/net/ip.rs#L1635-L1683
 531      struct ZeroSpan {
 532          size_t start_index{0};
 533          size_t len{0};
 534      };
 535  
 536      // Find longest sequence of consecutive all-zero fields. Use first zero sequence if two or more
 537      // zero sequences of equal length are found.
 538      ZeroSpan longest, current;
 539      for (size_t i{0}; i < groups.size(); ++i) {
 540          if (groups[i] != 0) {
 541              current = {i + 1, 0};
 542              continue;
 543          }
 544          current.len += 1;
 545          if (current.len > longest.len) {
 546              longest = current;
 547          }
 548      }
 549  
 550      std::string r;
 551      r.reserve(39);
 552      for (size_t i{0}; i < groups.size(); ++i) {
 553          // Replace the longest sequence of consecutive all-zero fields with two colons ("::").
 554          if (longest.len >= 2 && i >= longest.start_index && i < longest.start_index + longest.len) {
 555              if (i == longest.start_index) {
 556                  r += "::";
 557              }
 558              continue;
 559          }
 560          r += strprintf("%s%x", ((!r.empty() && r.back() != ':') ? ":" : ""), groups[i]);
 561      }
 562  
 563      if (scope_id != 0) {
 564          r += strprintf("%%%u", scope_id);
 565      }
 566  
 567      return r;
 568  }
 569  
 570  std::string OnionToString(Span<const uint8_t> addr)
 571  {
 572      uint8_t checksum[torv3::CHECKSUM_LEN];
 573      torv3::Checksum(addr, checksum);
 574      // TORv3 onion_address = base32(PUBKEY | CHECKSUM | VERSION) + ".onion"
 575      prevector<torv3::TOTAL_LEN, uint8_t> address{addr.begin(), addr.end()};
 576      address.insert(address.end(), checksum, checksum + torv3::CHECKSUM_LEN);
 577      address.insert(address.end(), torv3::VERSION, torv3::VERSION + sizeof(torv3::VERSION));
 578      return EncodeBase32(address) + ".onion";
 579  }
 580  
 581  std::string CNetAddr::ToStringAddr() const
 582  {
 583      switch (m_net) {
 584      case NET_IPV4:
 585          return IPv4ToString(m_addr);
 586      case NET_IPV6:
 587          return IPv6ToString(m_addr, m_scope_id);
 588      case NET_ONION:
 589          return OnionToString(m_addr);
 590      case NET_I2P:
 591          return EncodeBase32(m_addr, false /* don't pad with = */) + ".b32.i2p";
 592      case NET_CJDNS:
 593          return IPv6ToString(m_addr, 0);
 594      case NET_INTERNAL:
 595          return EncodeBase32(m_addr) + ".internal";
 596      case NET_UNROUTABLE: // m_net is never and should not be set to NET_UNROUTABLE
 597      case NET_MAX:        // m_net is never and should not be set to NET_MAX
 598          assert(false);
 599      } // no default case, so the compiler can warn about missing cases
 600  
 601      assert(false);
 602  }
 603  
 604  bool operator==(const CNetAddr& a, const CNetAddr& b)
 605  {
 606      return a.m_net == b.m_net && a.m_addr == b.m_addr;
 607  }
 608  
 609  bool operator<(const CNetAddr& a, const CNetAddr& b)
 610  {
 611      return std::tie(a.m_net, a.m_addr) < std::tie(b.m_net, b.m_addr);
 612  }
 613  
 614  /**
 615   * Try to get our IPv4 address.
 616   *
 617   * @param[out] pipv4Addr The in_addr struct to which to copy.
 618   *
 619   * @returns Whether or not the operation was successful, in particular, whether
 620   *          or not our address was an IPv4 address.
 621   *
 622   * @see CNetAddr::IsIPv4()
 623   */
 624  bool CNetAddr::GetInAddr(struct in_addr* pipv4Addr) const
 625  {
 626      if (!IsIPv4())
 627          return false;
 628      assert(sizeof(*pipv4Addr) == m_addr.size());
 629      memcpy(pipv4Addr, m_addr.data(), m_addr.size());
 630      return true;
 631  }
 632  
 633  /**
 634   * Try to get our IPv6 (or CJDNS) address.
 635   *
 636   * @param[out] pipv6Addr The in6_addr struct to which to copy.
 637   *
 638   * @returns Whether or not the operation was successful, in particular, whether
 639   *          or not our address was an IPv6 address.
 640   *
 641   * @see CNetAddr::IsIPv6()
 642   */
 643  bool CNetAddr::GetIn6Addr(struct in6_addr* pipv6Addr) const
 644  {
 645      if (!IsIPv6() && !IsCJDNS()) {
 646          return false;
 647      }
 648      assert(sizeof(*pipv6Addr) == m_addr.size());
 649      memcpy(pipv6Addr, m_addr.data(), m_addr.size());
 650      return true;
 651  }
 652  
 653  bool CNetAddr::HasLinkedIPv4() const
 654  {
 655      return IsRoutable() && (IsIPv4() || IsRFC6145() || IsRFC6052() || IsRFC3964() || IsRFC4380());
 656  }
 657  
 658  uint32_t CNetAddr::GetLinkedIPv4() const
 659  {
 660      if (IsIPv4()) {
 661          return ReadBE32(m_addr.data());
 662      } else if (IsRFC6052() || IsRFC6145()) {
 663          // mapped IPv4, SIIT translated IPv4: the IPv4 address is the last 4 bytes of the address
 664          return ReadBE32(Span{m_addr}.last(ADDR_IPV4_SIZE).data());
 665      } else if (IsRFC3964()) {
 666          // 6to4 tunneled IPv4: the IPv4 address is in bytes 2-6
 667          return ReadBE32(Span{m_addr}.subspan(2, ADDR_IPV4_SIZE).data());
 668      } else if (IsRFC4380()) {
 669          // Teredo tunneled IPv4: the IPv4 address is in the last 4 bytes of the address, but bitflipped
 670          return ~ReadBE32(Span{m_addr}.last(ADDR_IPV4_SIZE).data());
 671      }
 672      assert(false);
 673  }
 674  
 675  Network CNetAddr::GetNetClass() const
 676  {
 677      // Make sure that if we return NET_IPV6, then IsIPv6() is true. The callers expect that.
 678  
 679      // Check for "internal" first because such addresses are also !IsRoutable()
 680      // and we don't want to return NET_UNROUTABLE in that case.
 681      if (IsInternal()) {
 682          return NET_INTERNAL;
 683      }
 684      if (!IsRoutable()) {
 685          return NET_UNROUTABLE;
 686      }
 687      if (HasLinkedIPv4()) {
 688          return NET_IPV4;
 689      }
 690      return m_net;
 691  }
 692  
 693  std::vector<unsigned char> CNetAddr::GetAddrBytes() const
 694  {
 695      if (IsAddrV1Compatible()) {
 696          uint8_t serialized[V1_SERIALIZATION_SIZE];
 697          SerializeV1Array(serialized);
 698          return {std::begin(serialized), std::end(serialized)};
 699      }
 700      return std::vector<unsigned char>(m_addr.begin(), m_addr.end());
 701  }
 702  
 703  // private extensions to enum Network, only returned by GetExtNetwork,
 704  // and only used in GetReachabilityFrom
 705  static const int NET_TEREDO = NET_MAX;
 706  int static GetExtNetwork(const CNetAddr& addr)
 707  {
 708      if (addr.IsRFC4380())
 709          return NET_TEREDO;
 710      return addr.GetNetwork();
 711  }
 712  
 713  /** Calculates a metric for how reachable (*this) is from a given partner */
 714  int CNetAddr::GetReachabilityFrom(const CNetAddr& paddrPartner) const
 715  {
 716      enum Reachability {
 717          REACH_UNREACHABLE,
 718          REACH_DEFAULT,
 719          REACH_TEREDO,
 720          REACH_IPV6_WEAK,
 721          REACH_IPV4,
 722          REACH_IPV6_STRONG,
 723          REACH_PRIVATE
 724      };
 725  
 726      if (!IsRoutable() || IsInternal())
 727          return REACH_UNREACHABLE;
 728  
 729      int ourNet = GetExtNetwork(*this);
 730      int theirNet = GetExtNetwork(paddrPartner);
 731      bool fTunnel = IsRFC3964() || IsRFC6052() || IsRFC6145();
 732  
 733      switch(theirNet) {
 734      case NET_IPV4:
 735          switch(ourNet) {
 736          default:       return REACH_DEFAULT;
 737          case NET_IPV4: return REACH_IPV4;
 738          }
 739      case NET_IPV6:
 740          switch(ourNet) {
 741          default:         return REACH_DEFAULT;
 742          case NET_TEREDO: return REACH_TEREDO;
 743          case NET_IPV4:   return REACH_IPV4;
 744          case NET_IPV6:   return fTunnel ? REACH_IPV6_WEAK : REACH_IPV6_STRONG; // only prefer giving our IPv6 address if it's not tunnelled
 745          }
 746      case NET_ONION:
 747          switch(ourNet) {
 748          default:         return REACH_DEFAULT;
 749          case NET_IPV4:   return REACH_IPV4; // Tor users can connect to IPv4 as well
 750          case NET_ONION:    return REACH_PRIVATE;
 751          }
 752      case NET_I2P:
 753          switch (ourNet) {
 754          case NET_I2P: return REACH_PRIVATE;
 755          default: return REACH_DEFAULT;
 756          }
 757      case NET_CJDNS:
 758          switch (ourNet) {
 759          case NET_CJDNS: return REACH_PRIVATE;
 760          default: return REACH_DEFAULT;
 761          }
 762      case NET_TEREDO:
 763          switch(ourNet) {
 764          default:          return REACH_DEFAULT;
 765          case NET_TEREDO:  return REACH_TEREDO;
 766          case NET_IPV6:    return REACH_IPV6_WEAK;
 767          case NET_IPV4:    return REACH_IPV4;
 768          }
 769      case NET_UNROUTABLE:
 770      default:
 771          switch(ourNet) {
 772          default:          return REACH_DEFAULT;
 773          case NET_TEREDO:  return REACH_TEREDO;
 774          case NET_IPV6:    return REACH_IPV6_WEAK;
 775          case NET_IPV4:    return REACH_IPV4;
 776          case NET_ONION:     return REACH_PRIVATE; // either from Tor, or don't care about our address
 777          }
 778      }
 779  }
 780  
 781  CService::CService() : port(0)
 782  {
 783  }
 784  
 785  CService::CService(const CNetAddr& cip, uint16_t portIn) : CNetAddr(cip), port(portIn)
 786  {
 787  }
 788  
 789  CService::CService(const struct in_addr& ipv4Addr, uint16_t portIn) : CNetAddr(ipv4Addr), port(portIn)
 790  {
 791  }
 792  
 793  CService::CService(const struct in6_addr& ipv6Addr, uint16_t portIn) : CNetAddr(ipv6Addr), port(portIn)
 794  {
 795  }
 796  
 797  CService::CService(const struct sockaddr_in& addr) : CNetAddr(addr.sin_addr), port(ntohs(addr.sin_port))
 798  {
 799      assert(addr.sin_family == AF_INET);
 800  }
 801  
 802  CService::CService(const struct sockaddr_in6 &addr) : CNetAddr(addr.sin6_addr, addr.sin6_scope_id), port(ntohs(addr.sin6_port))
 803  {
 804     assert(addr.sin6_family == AF_INET6);
 805  }
 806  
 807  bool CService::SetSockAddr(const struct sockaddr *paddr)
 808  {
 809      switch (paddr->sa_family) {
 810      case AF_INET:
 811          *this = CService(*(const struct sockaddr_in*)paddr);
 812          return true;
 813      case AF_INET6:
 814          *this = CService(*(const struct sockaddr_in6*)paddr);
 815          return true;
 816      default:
 817          return false;
 818      }
 819  }
 820  
 821  sa_family_t CService::GetSAFamily() const
 822  {
 823      switch (m_net) {
 824      case NET_IPV4:
 825          return AF_INET;
 826      case NET_IPV6:
 827      case NET_CJDNS:
 828          return AF_INET6;
 829      default:
 830          return AF_UNSPEC;
 831      }
 832  }
 833  
 834  uint16_t CService::GetPort() const
 835  {
 836      return port;
 837  }
 838  
 839  bool operator==(const CService& a, const CService& b)
 840  {
 841      return static_cast<CNetAddr>(a) == static_cast<CNetAddr>(b) && a.port == b.port;
 842  }
 843  
 844  bool operator<(const CService& a, const CService& b)
 845  {
 846      return static_cast<CNetAddr>(a) < static_cast<CNetAddr>(b) || (static_cast<CNetAddr>(a) == static_cast<CNetAddr>(b) && a.port < b.port);
 847  }
 848  
 849  /**
 850   * Obtain the IPv4/6 socket address this represents.
 851   *
 852   * @param[out] paddr The obtained socket address.
 853   * @param[in,out] addrlen The size, in bytes, of the address structure pointed
 854   *                        to by paddr. The value that's pointed to by this
 855   *                        parameter might change after calling this function if
 856   *                        the size of the corresponding address structure
 857   *                        changed.
 858   *
 859   * @returns Whether or not the operation was successful.
 860   */
 861  bool CService::GetSockAddr(struct sockaddr* paddr, socklen_t *addrlen) const
 862  {
 863      if (IsIPv4()) {
 864          if (*addrlen < (socklen_t)sizeof(struct sockaddr_in))
 865              return false;
 866          *addrlen = sizeof(struct sockaddr_in);
 867          struct sockaddr_in *paddrin = (struct sockaddr_in*)paddr;
 868          memset(paddrin, 0, *addrlen);
 869          if (!GetInAddr(&paddrin->sin_addr))
 870              return false;
 871          paddrin->sin_family = AF_INET;
 872          paddrin->sin_port = htons(port);
 873          return true;
 874      }
 875      if (IsIPv6() || IsCJDNS()) {
 876          if (*addrlen < (socklen_t)sizeof(struct sockaddr_in6))
 877              return false;
 878          *addrlen = sizeof(struct sockaddr_in6);
 879          struct sockaddr_in6 *paddrin6 = (struct sockaddr_in6*)paddr;
 880          memset(paddrin6, 0, *addrlen);
 881          if (!GetIn6Addr(&paddrin6->sin6_addr))
 882              return false;
 883          paddrin6->sin6_scope_id = m_scope_id;
 884          paddrin6->sin6_family = AF_INET6;
 885          paddrin6->sin6_port = htons(port);
 886          return true;
 887      }
 888      return false;
 889  }
 890  
 891  /**
 892   * @returns An identifier unique to this service's address and port number.
 893   */
 894  std::vector<unsigned char> CService::GetKey() const
 895  {
 896      auto key = GetAddrBytes();
 897      key.push_back(port / 0x100); // most significant byte of our port
 898      key.push_back(port & 0x0FF); // least significant byte of our port
 899      return key;
 900  }
 901  
 902  std::string CService::ToStringAddrPort() const
 903  {
 904      const auto port_str = strprintf("%u", port);
 905  
 906      if (IsIPv4() || IsTor() || IsI2P() || IsInternal()) {
 907          return ToStringAddr() + ":" + port_str;
 908      } else {
 909          return "[" + ToStringAddr() + "]:" + port_str;
 910      }
 911  }
 912  
 913  CSubNet::CSubNet():
 914      valid(false)
 915  {
 916      memset(netmask, 0, sizeof(netmask));
 917  }
 918  
 919  CSubNet::CSubNet(const CNetAddr& addr, uint8_t mask) : CSubNet()
 920  {
 921      valid = (addr.IsIPv4() && mask <= ADDR_IPV4_SIZE * 8) ||
 922              (addr.IsIPv6() && mask <= ADDR_IPV6_SIZE * 8);
 923      if (!valid) {
 924          return;
 925      }
 926  
 927      assert(mask <= sizeof(netmask) * 8);
 928  
 929      network = addr;
 930  
 931      uint8_t n = mask;
 932      for (size_t i = 0; i < network.m_addr.size(); ++i) {
 933          const uint8_t bits = n < 8 ? n : 8;
 934          netmask[i] = (uint8_t)((uint8_t)0xFF << (8 - bits)); // Set first bits.
 935          network.m_addr[i] &= netmask[i]; // Normalize network according to netmask.
 936          n -= bits;
 937      }
 938  }
 939  
 940  /**
 941   * @returns The number of 1-bits in the prefix of the specified subnet mask. If
 942   *          the specified subnet mask is not a valid one, -1.
 943   */
 944  static inline int NetmaskBits(uint8_t x)
 945  {
 946      switch(x) {
 947      case 0x00: return 0;
 948      case 0x80: return 1;
 949      case 0xc0: return 2;
 950      case 0xe0: return 3;
 951      case 0xf0: return 4;
 952      case 0xf8: return 5;
 953      case 0xfc: return 6;
 954      case 0xfe: return 7;
 955      case 0xff: return 8;
 956      default: return -1;
 957      }
 958  }
 959  
 960  CSubNet::CSubNet(const CNetAddr& addr, const CNetAddr& mask) : CSubNet()
 961  {
 962      valid = (addr.IsIPv4() || addr.IsIPv6()) && addr.m_net == mask.m_net;
 963      if (!valid) {
 964          return;
 965      }
 966      // Check if `mask` contains 1-bits after 0-bits (which is an invalid netmask).
 967      bool zeros_found = false;
 968      for (auto b : mask.m_addr) {
 969          const int num_bits = NetmaskBits(b);
 970          if (num_bits == -1 || (zeros_found && num_bits != 0)) {
 971              valid = false;
 972              return;
 973          }
 974          if (num_bits < 8) {
 975              zeros_found = true;
 976          }
 977      }
 978  
 979      assert(mask.m_addr.size() <= sizeof(netmask));
 980  
 981      memcpy(netmask, mask.m_addr.data(), mask.m_addr.size());
 982  
 983      network = addr;
 984  
 985      // Normalize network according to netmask
 986      for (size_t x = 0; x < network.m_addr.size(); ++x) {
 987          network.m_addr[x] &= netmask[x];
 988      }
 989  }
 990  
 991  CSubNet::CSubNet(const CNetAddr& addr) : CSubNet()
 992  {
 993      switch (addr.m_net) {
 994      case NET_IPV4:
 995      case NET_IPV6:
 996          valid = true;
 997          assert(addr.m_addr.size() <= sizeof(netmask));
 998          memset(netmask, 0xFF, addr.m_addr.size());
 999          break;
1000      case NET_ONION:
1001      case NET_I2P:
1002      case NET_CJDNS:
1003          valid = true;
1004          break;
1005      case NET_INTERNAL:
1006      case NET_UNROUTABLE:
1007      case NET_MAX:
1008          return;
1009      }
1010  
1011      network = addr;
1012  }
1013  
1014  /**
1015   * @returns True if this subnet is valid, the specified address is valid, and
1016   *          the specified address belongs in this subnet.
1017   */
1018  bool CSubNet::Match(const CNetAddr &addr) const
1019  {
1020      if (!valid || !addr.IsValid() || network.m_net != addr.m_net)
1021          return false;
1022  
1023      switch (network.m_net) {
1024      case NET_IPV4:
1025      case NET_IPV6:
1026          break;
1027      case NET_ONION:
1028      case NET_I2P:
1029      case NET_CJDNS:
1030      case NET_INTERNAL:
1031          return addr == network;
1032      case NET_UNROUTABLE:
1033      case NET_MAX:
1034          return false;
1035      }
1036  
1037      assert(network.m_addr.size() == addr.m_addr.size());
1038      for (size_t x = 0; x < addr.m_addr.size(); ++x) {
1039          if ((addr.m_addr[x] & netmask[x]) != network.m_addr[x]) {
1040              return false;
1041          }
1042      }
1043      return true;
1044  }
1045  
1046  std::string CSubNet::ToString() const
1047  {
1048      std::string suffix;
1049  
1050      switch (network.m_net) {
1051      case NET_IPV4:
1052      case NET_IPV6: {
1053          assert(network.m_addr.size() <= sizeof(netmask));
1054  
1055          uint8_t cidr = 0;
1056  
1057          for (size_t i = 0; i < network.m_addr.size(); ++i) {
1058              if (netmask[i] == 0x00) {
1059                  break;
1060              }
1061              cidr += NetmaskBits(netmask[i]);
1062          }
1063  
1064          suffix = strprintf("/%u", cidr);
1065          break;
1066      }
1067      case NET_ONION:
1068      case NET_I2P:
1069      case NET_CJDNS:
1070      case NET_INTERNAL:
1071      case NET_UNROUTABLE:
1072      case NET_MAX:
1073          break;
1074      }
1075  
1076      return network.ToStringAddr() + suffix;
1077  }
1078  
1079  bool CSubNet::IsValid() const
1080  {
1081      return valid;
1082  }
1083  
1084  bool operator==(const CSubNet& a, const CSubNet& b)
1085  {
1086      return a.valid == b.valid && a.network == b.network && !memcmp(a.netmask, b.netmask, 16);
1087  }
1088  
1089  bool operator<(const CSubNet& a, const CSubNet& b)
1090  {
1091      return (a.network < b.network || (a.network == b.network && memcmp(a.netmask, b.netmask, 16) < 0));
1092  }