1  // Copyright (c) 2009-2010 Satoshi Nakamoto
   2  // Copyright (c) 2009-present 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 <string_view>
  22  #include <tuple>
  23  
  24  using util::ContainsNoNUL;
  25  using util::HasPrefix;
  26  
  27  CNetAddr::BIP155Network CNetAddr::GetBIP155Network() const
  28  {
  29      switch (m_net) {
  30      case NET_IPV4:
  31          return BIP155Network::IPV4;
  32      case NET_IPV6:
  33          return BIP155Network::IPV6;
  34      case NET_ONION:
  35          return BIP155Network::TORV3;
  36      case NET_I2P:
  37          return BIP155Network::I2P;
  38      case NET_CJDNS:
  39          return BIP155Network::CJDNS;
  40      case NET_INTERNAL:   // should have been handled before calling this function
  41      case NET_UNROUTABLE: // m_net is never and should not be set to NET_UNROUTABLE
  42      case NET_MAX:        // m_net is never and should not be set to NET_MAX
  43          assert(false);
  44      } // no default case, so the compiler can warn about missing cases
  45  
  46      assert(false);
  47  }
  48  
  49  bool CNetAddr::SetNetFromBIP155Network(uint8_t possible_bip155_net, size_t address_size)
  50  {
  51      switch (possible_bip155_net) {
  52      case BIP155Network::IPV4:
  53          if (address_size == ADDR_IPV4_SIZE) {
  54              m_net = NET_IPV4;
  55              return true;
  56          }
  57          throw std::ios_base::failure(
  58              strprintf("BIP155 IPv4 address with length %u (should be %u)", address_size,
  59                        ADDR_IPV4_SIZE));
  60      case BIP155Network::IPV6:
  61          if (address_size == ADDR_IPV6_SIZE) {
  62              m_net = NET_IPV6;
  63              return true;
  64          }
  65          throw std::ios_base::failure(
  66              strprintf("BIP155 IPv6 address with length %u (should be %u)", address_size,
  67                        ADDR_IPV6_SIZE));
  68      case BIP155Network::TORV3:
  69          if (address_size == ADDR_TORV3_SIZE) {
  70              m_net = NET_ONION;
  71              return true;
  72          }
  73          throw std::ios_base::failure(
  74              strprintf("BIP155 TORv3 address with length %u (should be %u)", address_size,
  75                        ADDR_TORV3_SIZE));
  76      case BIP155Network::I2P:
  77          if (address_size == ADDR_I2P_SIZE) {
  78              m_net = NET_I2P;
  79              return true;
  80          }
  81          throw std::ios_base::failure(
  82              strprintf("BIP155 I2P address with length %u (should be %u)", address_size,
  83                        ADDR_I2P_SIZE));
  84      case BIP155Network::CJDNS:
  85          if (address_size == ADDR_CJDNS_SIZE) {
  86              m_net = NET_CJDNS;
  87              return true;
  88          }
  89          throw std::ios_base::failure(
  90              strprintf("BIP155 CJDNS address with length %u (should be %u)", address_size,
  91                        ADDR_CJDNS_SIZE));
  92      }
  93  
  94      // Don't throw on addresses with unknown network ids (maybe from the future).
  95      // Instead silently drop them and have the unserialization code consume
  96      // subsequent ones which may be known to us.
  97      return false;
  98  }
  99  
 100  /**
 101   * Construct an unspecified IPv6 network address (::/128).
 102   *
 103   * @note This address is considered invalid by CNetAddr::IsValid()
 104   */
 105  CNetAddr::CNetAddr() = default;
 106  
 107  void CNetAddr::SetIP(const CNetAddr& ipIn)
 108  {
 109      // Size check.
 110      switch (ipIn.m_net) {
 111      case NET_IPV4:
 112          assert(ipIn.m_addr.size() == ADDR_IPV4_SIZE);
 113          break;
 114      case NET_IPV6:
 115          assert(ipIn.m_addr.size() == ADDR_IPV6_SIZE);
 116          break;
 117      case NET_ONION:
 118          assert(ipIn.m_addr.size() == ADDR_TORV3_SIZE);
 119          break;
 120      case NET_I2P:
 121          assert(ipIn.m_addr.size() == ADDR_I2P_SIZE);
 122          break;
 123      case NET_CJDNS:
 124          assert(ipIn.m_addr.size() == ADDR_CJDNS_SIZE);
 125          break;
 126      case NET_INTERNAL:
 127          assert(ipIn.m_addr.size() == ADDR_INTERNAL_SIZE);
 128          break;
 129      case NET_UNROUTABLE:
 130      case NET_MAX:
 131          assert(false);
 132      } // no default case, so the compiler can warn about missing cases
 133  
 134      m_net = ipIn.m_net;
 135      m_addr = ipIn.m_addr;
 136  }
 137  
 138  void CNetAddr::SetLegacyIPv6(std::span<const uint8_t> ipv6)
 139  {
 140      assert(ipv6.size() == ADDR_IPV6_SIZE);
 141  
 142      size_t skip{0};
 143  
 144      if (HasPrefix(ipv6, IPV4_IN_IPV6_PREFIX)) {
 145          // IPv4-in-IPv6
 146          m_net = NET_IPV4;
 147          skip = sizeof(IPV4_IN_IPV6_PREFIX);
 148      } else if (HasPrefix(ipv6, TORV2_IN_IPV6_PREFIX)) {
 149          // TORv2-in-IPv6 (unsupported). Unserialize as !IsValid(), thus ignoring them.
 150          // Mimic a default-constructed CNetAddr object which is !IsValid() and thus
 151          // will not be gossiped, but continue reading next addresses from the stream.
 152          m_net = NET_IPV6;
 153          m_addr.assign(ADDR_IPV6_SIZE, 0x0);
 154          return;
 155      } else if (HasPrefix(ipv6, INTERNAL_IN_IPV6_PREFIX)) {
 156          // Internal-in-IPv6
 157          m_net = NET_INTERNAL;
 158          skip = sizeof(INTERNAL_IN_IPV6_PREFIX);
 159      } else {
 160          // IPv6
 161          m_net = NET_IPV6;
 162      }
 163  
 164      m_addr.assign(ipv6.begin() + skip, ipv6.end());
 165  }
 166  
 167  /**
 168   * Create an "internal" address that represents a name or FQDN. AddrMan uses
 169   * these fake addresses to keep track of which DNS seeds were used.
 170   * @returns Whether or not the operation was successful.
 171   * @see NET_INTERNAL, INTERNAL_IN_IPV6_PREFIX, CNetAddr::IsInternal(), CNetAddr::IsRFC4193()
 172   */
 173  bool CNetAddr::SetInternal(const std::string &name)
 174  {
 175      if (name.empty()) {
 176          return false;
 177      }
 178      m_net = NET_INTERNAL;
 179      unsigned char hash[32] = {};
 180      CSHA256().Write((const unsigned char*)name.data(), name.size()).Finalize(hash);
 181      m_addr.assign(hash, hash + ADDR_INTERNAL_SIZE);
 182      return true;
 183  }
 184  
 185  namespace torv3 {
 186  // https://gitlab.torproject.org/tpo/core/torspec/-/tree/main/spec/rend-spec
 187  static constexpr size_t CHECKSUM_LEN = 2;
 188  static const unsigned char VERSION[] = {3};
 189  static constexpr size_t TOTAL_LEN = ADDR_TORV3_SIZE + CHECKSUM_LEN + sizeof(VERSION);
 190  
 191  static void Checksum(std::span<const uint8_t> addr_pubkey, uint8_t (&checksum)[CHECKSUM_LEN])
 192  {
 193      // TORv3 CHECKSUM = H(".onion checksum" | PUBKEY | VERSION)[:2]
 194      static const unsigned char prefix[] = ".onion checksum";
 195      static constexpr size_t prefix_len = 15;
 196  
 197      SHA3_256 hasher;
 198  
 199      hasher.Write(std::span{prefix}.first(prefix_len));
 200      hasher.Write(addr_pubkey);
 201      hasher.Write(VERSION);
 202  
 203      uint8_t checksum_full[SHA3_256::OUTPUT_SIZE];
 204  
 205      hasher.Finalize(checksum_full);
 206  
 207      memcpy(checksum, checksum_full, sizeof(checksum));
 208  }
 209  
 210  }; // namespace torv3
 211  
 212  bool CNetAddr::SetSpecial(std::string_view addr)
 213  {
 214      if (!ContainsNoNUL(addr)) {
 215          return false;
 216      }
 217  
 218      if (SetTor(addr)) {
 219          return true;
 220      }
 221  
 222      if (SetI2P(addr)) {
 223          return true;
 224      }
 225  
 226      return false;
 227  }
 228  
 229  bool CNetAddr::SetTor(std::string_view addr)
 230  {
 231      if (!addr.ends_with(".onion")) return false;
 232      addr.remove_suffix(6);
 233      auto input = DecodeBase32(addr);
 234  
 235      if (!input) {
 236          return false;
 237      }
 238  
 239      if (input->size() == torv3::TOTAL_LEN) {
 240          std::span<const uint8_t> input_pubkey{input->data(), ADDR_TORV3_SIZE};
 241          std::span<const uint8_t> input_checksum{input->data() + ADDR_TORV3_SIZE, torv3::CHECKSUM_LEN};
 242          std::span<const uint8_t> input_version{input->data() + ADDR_TORV3_SIZE + torv3::CHECKSUM_LEN, sizeof(torv3::VERSION)};
 243  
 244          if (!std::ranges::equal(input_version, torv3::VERSION)) {
 245              return false;
 246          }
 247  
 248          uint8_t calculated_checksum[torv3::CHECKSUM_LEN];
 249          torv3::Checksum(input_pubkey, calculated_checksum);
 250  
 251          if (!std::ranges::equal(input_checksum, calculated_checksum)) {
 252              return false;
 253          }
 254  
 255          m_net = NET_ONION;
 256          m_addr.assign(input_pubkey.begin(), input_pubkey.end());
 257          return true;
 258      }
 259  
 260      return false;
 261  }
 262  
 263  bool CNetAddr::SetI2P(std::string_view addr)
 264  {
 265      // I2P addresses that we support consist of 52 base32 characters + ".b32.i2p".
 266      static constexpr size_t b32_len{52};
 267      static const char* suffix{".b32.i2p"};
 268      static constexpr size_t suffix_len{8};
 269  
 270      if (addr.size() != b32_len + suffix_len || ToLower(addr.substr(b32_len)) != suffix) {
 271          return false;
 272      }
 273  
 274      // Remove the ".b32.i2p" suffix and pad to a multiple of 8 chars, so DecodeBase32()
 275      // can decode it.
 276      const std::string b32_padded{tfm::format("%s====", addr.substr(0, b32_len))};
 277  
 278      auto address_bytes = DecodeBase32(b32_padded);
 279  
 280      if (!address_bytes || address_bytes->size() != ADDR_I2P_SIZE) {
 281          return false;
 282      }
 283  
 284      m_net = NET_I2P;
 285      m_addr.assign(address_bytes->begin(), address_bytes->end());
 286  
 287      return true;
 288  }
 289  
 290  CNetAddr::CNetAddr(const struct in_addr& ipv4Addr)
 291  {
 292      m_net = NET_IPV4;
 293      const uint8_t* ptr = reinterpret_cast<const uint8_t*>(&ipv4Addr);
 294      m_addr.assign(ptr, ptr + ADDR_IPV4_SIZE);
 295  }
 296  
 297  CNetAddr::CNetAddr(const struct in6_addr& ipv6Addr, const uint32_t scope)
 298  {
 299      SetLegacyIPv6({reinterpret_cast<const uint8_t*>(&ipv6Addr), sizeof(ipv6Addr)});
 300      m_scope_id = scope;
 301  }
 302  
 303  bool CNetAddr::IsBindAny() const
 304  {
 305      if (!IsIPv4() && !IsIPv6()) {
 306          return false;
 307      }
 308      return std::all_of(m_addr.begin(), m_addr.end(), [](uint8_t b) { return b == 0; });
 309  }
 310  
 311  bool CNetAddr::IsRFC1918() const
 312  {
 313      return IsIPv4() && (
 314          m_addr[0] == 10 ||
 315          (m_addr[0] == 192 && m_addr[1] == 168) ||
 316          (m_addr[0] == 172 && m_addr[1] >= 16 && m_addr[1] <= 31));
 317  }
 318  
 319  bool CNetAddr::IsRFC2544() const
 320  {
 321      return IsIPv4() && m_addr[0] == 198 && (m_addr[1] == 18 || m_addr[1] == 19);
 322  }
 323  
 324  bool CNetAddr::IsRFC3927() const
 325  {
 326      return IsIPv4() && HasPrefix(m_addr, std::array<uint8_t, 2>{169, 254});
 327  }
 328  
 329  bool CNetAddr::IsRFC6598() const
 330  {
 331      return IsIPv4() && m_addr[0] == 100 && m_addr[1] >= 64 && m_addr[1] <= 127;
 332  }
 333  
 334  bool CNetAddr::IsRFC5737() const
 335  {
 336      return IsIPv4() && (HasPrefix(m_addr, std::array<uint8_t, 3>{192, 0, 2}) ||
 337                          HasPrefix(m_addr, std::array<uint8_t, 3>{198, 51, 100}) ||
 338                          HasPrefix(m_addr, std::array<uint8_t, 3>{203, 0, 113}));
 339  }
 340  
 341  bool CNetAddr::IsRFC3849() const
 342  {
 343      return IsIPv6() && HasPrefix(m_addr, std::array<uint8_t, 4>{0x20, 0x01, 0x0D, 0xB8});
 344  }
 345  
 346  bool CNetAddr::IsRFC3964() const
 347  {
 348      return IsIPv6() && HasPrefix(m_addr, std::array<uint8_t, 2>{0x20, 0x02});
 349  }
 350  
 351  bool CNetAddr::IsRFC6052() const
 352  {
 353      return IsIPv6() &&
 354             HasPrefix(m_addr, std::array<uint8_t, 12>{0x00, 0x64, 0xFF, 0x9B, 0x00, 0x00,
 355                                                       0x00, 0x00, 0x00, 0x00, 0x00, 0x00});
 356  }
 357  
 358  bool CNetAddr::IsRFC4380() const
 359  {
 360      return IsIPv6() && HasPrefix(m_addr, std::array<uint8_t, 4>{0x20, 0x01, 0x00, 0x00});
 361  }
 362  
 363  bool CNetAddr::IsRFC4862() const
 364  {
 365      return IsIPv6() && HasPrefix(m_addr, std::array<uint8_t, 8>{0xFE, 0x80, 0x00, 0x00,
 366                                                                  0x00, 0x00, 0x00, 0x00});
 367  }
 368  
 369  bool CNetAddr::IsRFC4193() const
 370  {
 371      return IsIPv6() && (m_addr[0] & 0xFE) == 0xFC;
 372  }
 373  
 374  bool CNetAddr::IsRFC6145() const
 375  {
 376      return IsIPv6() &&
 377             HasPrefix(m_addr, std::array<uint8_t, 12>{0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 378                                                       0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00});
 379  }
 380  
 381  bool CNetAddr::IsRFC4843() const
 382  {
 383      return IsIPv6() && HasPrefix(m_addr, std::array<uint8_t, 3>{0x20, 0x01, 0x00}) &&
 384             (m_addr[3] & 0xF0) == 0x10;
 385  }
 386  
 387  bool CNetAddr::IsRFC7343() const
 388  {
 389      return IsIPv6() && HasPrefix(m_addr, std::array<uint8_t, 3>{0x20, 0x01, 0x00}) &&
 390             (m_addr[3] & 0xF0) == 0x20;
 391  }
 392  
 393  bool CNetAddr::IsHeNet() const
 394  {
 395      return IsIPv6() && HasPrefix(m_addr, std::array<uint8_t, 4>{0x20, 0x01, 0x04, 0x70});
 396  }
 397  
 398  bool CNetAddr::IsLocal() const
 399  {
 400      // IPv4 loopback (127.0.0.0/8 or 0.0.0.0/8)
 401      if (IsIPv4() && (m_addr[0] == 127 || m_addr[0] == 0)) {
 402          return true;
 403      }
 404  
 405      // IPv6 loopback (::1/128)
 406      static const unsigned char pchLocal[16] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
 407      if (IsIPv6() && memcmp(m_addr.data(), pchLocal, sizeof(pchLocal)) == 0) {
 408          return true;
 409      }
 410  
 411      return false;
 412  }
 413  
 414  /**
 415   * @returns Whether or not this network address is a valid address that @a could
 416   *          be used to refer to an actual host.
 417   *
 418   * @note A valid address may or may not be publicly routable on the global
 419   *       internet. As in, the set of valid addresses is a superset of the set of
 420   *       publicly routable addresses.
 421   *
 422   * @see CNetAddr::IsRoutable()
 423   */
 424  bool CNetAddr::IsValid() const
 425  {
 426      // unspecified IPv6 address (::/128)
 427      unsigned char ipNone6[16] = {};
 428      if (IsIPv6() && memcmp(m_addr.data(), ipNone6, sizeof(ipNone6)) == 0) {
 429          return false;
 430      }
 431  
 432      if (IsCJDNS() && !HasCJDNSPrefix()) {
 433          return false;
 434      }
 435  
 436      // documentation IPv6 address
 437      if (IsRFC3849())
 438          return false;
 439  
 440      if (IsInternal())
 441          return false;
 442  
 443      if (IsIPv4()) {
 444          const uint32_t addr = ReadBE32(m_addr.data());
 445          if (addr == INADDR_ANY || addr == INADDR_NONE) {
 446              return false;
 447          }
 448      }
 449  
 450      return true;
 451  }
 452  
 453  /**
 454   * @returns Whether or not this network address is publicly routable on the
 455   *          global internet.
 456   *
 457   * @note A routable address is always valid. As in, the set of routable addresses
 458   *       is a subset of the set of valid addresses.
 459   *
 460   * @see CNetAddr::IsValid()
 461   */
 462  bool CNetAddr::IsRoutable() const
 463  {
 464      return IsValid() && !(IsRFC1918() || IsRFC2544() || IsRFC3927() || IsRFC4862() || IsRFC6598() || IsRFC5737() || IsRFC4193() || IsRFC4843() || IsRFC7343() || IsLocal() || IsInternal());
 465  }
 466  
 467  /**
 468   * @returns Whether or not this is a dummy address that represents a name.
 469   *
 470   * @see CNetAddr::SetInternal(const std::string &)
 471   */
 472  bool CNetAddr::IsInternal() const
 473  {
 474     return m_net == NET_INTERNAL;
 475  }
 476  
 477  bool CNetAddr::IsAddrV1Compatible() const
 478  {
 479      switch (m_net) {
 480      case NET_IPV4:
 481      case NET_IPV6:
 482      case NET_INTERNAL:
 483          return true;
 484      case NET_ONION:
 485      case NET_I2P:
 486      case NET_CJDNS:
 487          return false;
 488      case NET_UNROUTABLE: // m_net is never and should not be set to NET_UNROUTABLE
 489      case NET_MAX:        // m_net is never and should not be set to NET_MAX
 490          assert(false);
 491      } // no default case, so the compiler can warn about missing cases
 492  
 493      assert(false);
 494  }
 495  
 496  enum Network CNetAddr::GetNetwork() const
 497  {
 498      if (IsInternal())
 499          return NET_INTERNAL;
 500  
 501      if (!IsRoutable())
 502          return NET_UNROUTABLE;
 503  
 504      return m_net;
 505  }
 506  
 507  static std::string IPv4ToString(std::span<const uint8_t> a)
 508  {
 509      return strprintf("%u.%u.%u.%u", a[0], a[1], a[2], a[3]);
 510  }
 511  
 512  // Return an IPv6 address text representation with zero compression as described in RFC 5952
 513  // ("A Recommendation for IPv6 Address Text Representation").
 514  static std::string IPv6ToString(std::span<const uint8_t> a, uint32_t scope_id)
 515  {
 516      assert(a.size() == ADDR_IPV6_SIZE);
 517      const std::array groups{
 518          ReadBE16(&a[0]),
 519          ReadBE16(&a[2]),
 520          ReadBE16(&a[4]),
 521          ReadBE16(&a[6]),
 522          ReadBE16(&a[8]),
 523          ReadBE16(&a[10]),
 524          ReadBE16(&a[12]),
 525          ReadBE16(&a[14]),
 526      };
 527  
 528      // The zero compression implementation is inspired by Rust's std::net::Ipv6Addr, see
 529      // https://github.com/rust-lang/rust/blob/cc4103089f40a163f6d143f06359cba7043da29b/library/std/src/net/ip.rs#L1635-L1683
 530      struct ZeroSpan {
 531          size_t start_index{0};
 532          size_t len{0};
 533      };
 534  
 535      // Find longest sequence of consecutive all-zero fields. Use first zero sequence if two or more
 536      // zero sequences of equal length are found.
 537      ZeroSpan longest, current;
 538      for (size_t i{0}; i < groups.size(); ++i) {
 539          if (groups[i] != 0) {
 540              current = {i + 1, 0};
 541              continue;
 542          }
 543          current.len += 1;
 544          if (current.len > longest.len) {
 545              longest = current;
 546          }
 547      }
 548  
 549      std::string r;
 550      r.reserve(39);
 551      for (size_t i{0}; i < groups.size(); ++i) {
 552          // Replace the longest sequence of consecutive all-zero fields with two colons ("::").
 553          if (longest.len >= 2 && i >= longest.start_index && i < longest.start_index + longest.len) {
 554              if (i == longest.start_index) {
 555                  r += "::";
 556              }
 557              continue;
 558          }
 559          r += strprintf("%s%x", ((!r.empty() && r.back() != ':') ? ":" : ""), groups[i]);
 560      }
 561  
 562      if (scope_id != 0) {
 563          r += strprintf("%%%u", scope_id);
 564      }
 565  
 566      return r;
 567  }
 568  
 569  std::string OnionToString(std::span<const uint8_t> addr)
 570  {
 571      uint8_t checksum[torv3::CHECKSUM_LEN];
 572      torv3::Checksum(addr, checksum);
 573      // TORv3 onion_address = base32(PUBKEY | CHECKSUM | VERSION) + ".onion"
 574      prevector<torv3::TOTAL_LEN, uint8_t> address{addr.begin(), addr.end()};
 575      address.insert(address.end(), checksum, checksum + torv3::CHECKSUM_LEN);
 576      address.insert(address.end(), torv3::VERSION, torv3::VERSION + sizeof(torv3::VERSION));
 577      return EncodeBase32(address) + ".onion";
 578  }
 579  
 580  std::string CNetAddr::ToStringAddr() const
 581  {
 582      switch (m_net) {
 583      case NET_IPV4:
 584          return IPv4ToString(m_addr);
 585      case NET_IPV6:
 586          return IPv6ToString(m_addr, m_scope_id);
 587      case NET_ONION:
 588          return OnionToString(m_addr);
 589      case NET_I2P:
 590          return EncodeBase32(m_addr, false /* don't pad with = */) + ".b32.i2p";
 591      case NET_CJDNS:
 592          return IPv6ToString(m_addr, 0);
 593      case NET_INTERNAL:
 594          return EncodeBase32(m_addr) + ".internal";
 595      case NET_UNROUTABLE: // m_net is never and should not be set to NET_UNROUTABLE
 596      case NET_MAX:        // m_net is never and should not be set to NET_MAX
 597          assert(false);
 598      } // no default case, so the compiler can warn about missing cases
 599  
 600      assert(false);
 601  }
 602  
 603  bool operator==(const CNetAddr& a, const CNetAddr& b)
 604  {
 605      return a.m_net == b.m_net && a.m_addr == b.m_addr;
 606  }
 607  
 608  bool operator<(const CNetAddr& a, const CNetAddr& b)
 609  {
 610      return std::tie(a.m_net, a.m_addr) < std::tie(b.m_net, b.m_addr);
 611  }
 612  
 613  /**
 614   * Try to get our IPv4 address.
 615   *
 616   * @param[out] pipv4Addr The in_addr struct to which to copy.
 617   *
 618   * @returns Whether or not the operation was successful, in particular, whether
 619   *          or not our address was an IPv4 address.
 620   *
 621   * @see CNetAddr::IsIPv4()
 622   */
 623  bool CNetAddr::GetInAddr(struct in_addr* pipv4Addr) const
 624  {
 625      if (!IsIPv4())
 626          return false;
 627      assert(sizeof(*pipv4Addr) == m_addr.size());
 628      memcpy(pipv4Addr, m_addr.data(), m_addr.size());
 629      return true;
 630  }
 631  
 632  /**
 633   * Try to get our IPv6 (or CJDNS) address.
 634   *
 635   * @param[out] pipv6Addr The in6_addr struct to which to copy.
 636   *
 637   * @returns Whether or not the operation was successful, in particular, whether
 638   *          or not our address was an IPv6 address.
 639   *
 640   * @see CNetAddr::IsIPv6()
 641   */
 642  bool CNetAddr::GetIn6Addr(struct in6_addr* pipv6Addr) const
 643  {
 644      if (!IsIPv6() && !IsCJDNS()) {
 645          return false;
 646      }
 647      assert(sizeof(*pipv6Addr) == m_addr.size());
 648      memcpy(pipv6Addr, m_addr.data(), m_addr.size());
 649      return true;
 650  }
 651  
 652  bool CNetAddr::HasLinkedIPv4() const
 653  {
 654      return IsRoutable() && (IsIPv4() || IsRFC6145() || IsRFC6052() || IsRFC3964() || IsRFC4380());
 655  }
 656  
 657  uint32_t CNetAddr::GetLinkedIPv4() const
 658  {
 659      if (IsIPv4()) {
 660          return ReadBE32(m_addr.data());
 661      } else if (IsRFC6052() || IsRFC6145()) {
 662          // mapped IPv4, SIIT translated IPv4: the IPv4 address is the last 4 bytes of the address
 663          return ReadBE32(std::span{m_addr}.last(ADDR_IPV4_SIZE).data());
 664      } else if (IsRFC3964()) {
 665          // 6to4 tunneled IPv4: the IPv4 address is in bytes 2-6
 666          return ReadBE32(std::span{m_addr}.subspan(2, ADDR_IPV4_SIZE).data());
 667      } else if (IsRFC4380()) {
 668          // Teredo tunneled IPv4: the IPv4 address is in the last 4 bytes of the address, but bitflipped
 669          return ~ReadBE32(std::span{m_addr}.last(ADDR_IPV4_SIZE).data());
 670      }
 671      assert(false);
 672  }
 673  
 674  Network CNetAddr::GetNetClass() const
 675  {
 676      // Make sure that if we return NET_IPV6, then IsIPv6() is true. The callers expect that.
 677  
 678      // Check for "internal" first because such addresses are also !IsRoutable()
 679      // and we don't want to return NET_UNROUTABLE in that case.
 680      if (IsInternal()) {
 681          return NET_INTERNAL;
 682      }
 683      if (!IsRoutable()) {
 684          return NET_UNROUTABLE;
 685      }
 686      if (HasLinkedIPv4()) {
 687          return NET_IPV4;
 688      }
 689      return m_net;
 690  }
 691  
 692  std::vector<unsigned char> CNetAddr::GetAddrBytes() const
 693  {
 694      if (IsAddrV1Compatible()) {
 695          uint8_t serialized[V1_SERIALIZATION_SIZE];
 696          SerializeV1Array(serialized);
 697          return {std::begin(serialized), std::end(serialized)};
 698      }
 699      return std::vector<unsigned char>(m_addr.begin(), m_addr.end());
 700  }
 701  
 702  // private extensions to enum Network, only returned by GetExtNetwork,
 703  // and only used in GetReachabilityFrom
 704  static const int NET_TEREDO = NET_MAX;
 705  int static GetExtNetwork(const CNetAddr& addr)
 706  {
 707      if (addr.IsRFC4380())
 708          return NET_TEREDO;
 709      return addr.GetNetwork();
 710  }
 711  
 712  /** Calculates a metric for how reachable (*this) is from a given partner */
 713  int CNetAddr::GetReachabilityFrom(const CNetAddr& paddrPartner) const
 714  {
 715      enum Reachability {
 716          REACH_UNREACHABLE,
 717          REACH_DEFAULT,
 718          REACH_TEREDO,
 719          REACH_IPV6_WEAK,
 720          REACH_IPV4,
 721          REACH_IPV6_STRONG,
 722          REACH_PRIVATE
 723      };
 724  
 725      if (!IsRoutable() || IsInternal())
 726          return REACH_UNREACHABLE;
 727  
 728      int ourNet = GetExtNetwork(*this);
 729      int theirNet = GetExtNetwork(paddrPartner);
 730      bool fTunnel = IsRFC3964() || IsRFC6052() || IsRFC6145();
 731  
 732      switch(theirNet) {
 733      case NET_IPV4:
 734          switch(ourNet) {
 735          default:       return REACH_DEFAULT;
 736          case NET_IPV4: return REACH_IPV4;
 737          }
 738      case NET_IPV6:
 739          switch(ourNet) {
 740          default:         return REACH_DEFAULT;
 741          case NET_TEREDO: return REACH_TEREDO;
 742          case NET_IPV4:   return REACH_IPV4;
 743          case NET_IPV6:   return fTunnel ? REACH_IPV6_WEAK : REACH_IPV6_STRONG; // only prefer giving our IPv6 address if it's not tunnelled
 744          }
 745      case NET_ONION:
 746          switch(ourNet) {
 747          default:         return REACH_DEFAULT;
 748          case NET_IPV4:   return REACH_IPV4; // Tor users can connect to IPv4 as well
 749          case NET_ONION:    return REACH_PRIVATE;
 750          }
 751      case NET_I2P:
 752          switch (ourNet) {
 753          case NET_I2P: return REACH_PRIVATE;
 754          default: return REACH_DEFAULT;
 755          }
 756      case NET_CJDNS:
 757          switch (ourNet) {
 758          case NET_CJDNS: return REACH_PRIVATE;
 759          default: return REACH_DEFAULT;
 760          }
 761      case NET_TEREDO:
 762          switch(ourNet) {
 763          default:          return REACH_DEFAULT;
 764          case NET_TEREDO:  return REACH_TEREDO;
 765          case NET_IPV6:    return REACH_IPV6_WEAK;
 766          case NET_IPV4:    return REACH_IPV4;
 767          }
 768      case NET_UNROUTABLE:
 769      default:
 770          switch(ourNet) {
 771          default:          return REACH_DEFAULT;
 772          case NET_TEREDO:  return REACH_TEREDO;
 773          case NET_IPV6:    return REACH_IPV6_WEAK;
 774          case NET_IPV4:    return REACH_IPV4;
 775          case NET_ONION:     return REACH_PRIVATE; // either from Tor, or don't care about our address
 776          }
 777      }
 778  }
 779  
 780  CService::CService() : port(0)
 781  {
 782  }
 783  
 784  CService::CService(const CNetAddr& cip, uint16_t portIn) : CNetAddr(cip), port(portIn)
 785  {
 786  }
 787  
 788  CService::CService(const struct in_addr& ipv4Addr, uint16_t portIn) : CNetAddr(ipv4Addr), port(portIn)
 789  {
 790  }
 791  
 792  CService::CService(const struct in6_addr& ipv6Addr, uint16_t portIn) : CNetAddr(ipv6Addr), port(portIn)
 793  {
 794  }
 795  
 796  CService::CService(const struct sockaddr_in& addr) : CNetAddr(addr.sin_addr), port(ntohs(addr.sin_port))
 797  {
 798      assert(addr.sin_family == AF_INET);
 799  }
 800  
 801  CService::CService(const struct sockaddr_in6 &addr) : CNetAddr(addr.sin6_addr, addr.sin6_scope_id), port(ntohs(addr.sin6_port))
 802  {
 803     assert(addr.sin6_family == AF_INET6);
 804  }
 805  
 806  bool CService::SetSockAddr(const struct sockaddr *paddr, socklen_t addrlen)
 807  {
 808      switch (paddr->sa_family) {
 809      case AF_INET:
 810          if (addrlen != sizeof(struct sockaddr_in)) return false;
 811          *this = CService(*(const struct sockaddr_in*)paddr);
 812          return true;
 813      case AF_INET6:
 814          if (addrlen != sizeof(struct sockaddr_in6)) return false;
 815          *this = CService(*(const struct sockaddr_in6*)paddr);
 816          return true;
 817      default:
 818          return false;
 819      }
 820  }
 821  
 822  sa_family_t CService::GetSAFamily() const
 823  {
 824      switch (m_net) {
 825      case NET_IPV4:
 826          return AF_INET;
 827      case NET_IPV6:
 828      case NET_CJDNS:
 829          return AF_INET6;
 830      default:
 831          return AF_UNSPEC;
 832      }
 833  }
 834  
 835  uint16_t CService::GetPort() const
 836  {
 837      return port;
 838  }
 839  
 840  bool operator==(const CService& a, const CService& b)
 841  {
 842      return static_cast<CNetAddr>(a) == static_cast<CNetAddr>(b) && a.port == b.port;
 843  }
 844  
 845  bool operator<(const CService& a, const CService& b)
 846  {
 847      return static_cast<CNetAddr>(a) < static_cast<CNetAddr>(b) || (static_cast<CNetAddr>(a) == static_cast<CNetAddr>(b) && a.port < b.port);
 848  }
 849  
 850  /**
 851   * Obtain the IPv4/6 socket address this represents.
 852   *
 853   * @param[out] paddr The obtained socket address.
 854   * @param[in,out] addrlen The size, in bytes, of the address structure pointed
 855   *                        to by paddr. The value that's pointed to by this
 856   *                        parameter might change after calling this function if
 857   *                        the size of the corresponding address structure
 858   *                        changed.
 859   *
 860   * @returns Whether or not the operation was successful.
 861   */
 862  bool CService::GetSockAddr(struct sockaddr* paddr, socklen_t *addrlen) const
 863  {
 864      if (IsIPv4()) {
 865          if (*addrlen < (socklen_t)sizeof(struct sockaddr_in))
 866              return false;
 867          *addrlen = sizeof(struct sockaddr_in);
 868          struct sockaddr_in *paddrin = (struct sockaddr_in*)paddr;
 869          memset(paddrin, 0, *addrlen);
 870          if (!GetInAddr(&paddrin->sin_addr))
 871              return false;
 872          paddrin->sin_family = AF_INET;
 873          paddrin->sin_port = htons(port);
 874          return true;
 875      }
 876      if (IsIPv6() || IsCJDNS()) {
 877          if (*addrlen < (socklen_t)sizeof(struct sockaddr_in6))
 878              return false;
 879          *addrlen = sizeof(struct sockaddr_in6);
 880          struct sockaddr_in6 *paddrin6 = (struct sockaddr_in6*)paddr;
 881          memset(paddrin6, 0, *addrlen);
 882          if (!GetIn6Addr(&paddrin6->sin6_addr))
 883              return false;
 884          paddrin6->sin6_scope_id = m_scope_id;
 885          paddrin6->sin6_family = AF_INET6;
 886          paddrin6->sin6_port = htons(port);
 887          return true;
 888      }
 889      return false;
 890  }
 891  
 892  /**
 893   * @returns An identifier unique to this service's address and port number.
 894   */
 895  std::vector<unsigned char> CService::GetKey() const
 896  {
 897      auto key = GetAddrBytes();
 898      key.push_back(port / 0x100); // most significant byte of our port
 899      key.push_back(port & 0x0FF); // least significant byte of our port
 900      return key;
 901  }
 902  
 903  std::string CService::ToStringAddrPort() const
 904  {
 905      const auto port_str = strprintf("%u", port);
 906  
 907      if (IsIPv4() || IsTor() || IsI2P() || IsInternal()) {
 908          return ToStringAddr() + ":" + port_str;
 909      } else {
 910          return "[" + ToStringAddr() + "]:" + port_str;
 911      }
 912  }
 913  
 914  CSubNet::CSubNet():
 915      valid(false)
 916  {
 917      memset(netmask, 0, sizeof(netmask));
 918  }
 919  
 920  CSubNet::CSubNet(const CNetAddr& addr, uint8_t mask) : CSubNet()
 921  {
 922      valid = (addr.IsIPv4() && mask <= ADDR_IPV4_SIZE * 8) ||
 923              (addr.IsIPv6() && mask <= ADDR_IPV6_SIZE * 8);
 924      if (!valid) {
 925          return;
 926      }
 927  
 928      assert(mask <= sizeof(netmask) * 8);
 929  
 930      network = addr;
 931  
 932      uint8_t n = mask;
 933      for (size_t i = 0; i < network.m_addr.size(); ++i) {
 934          const uint8_t bits = n < 8 ? n : 8;
 935          netmask[i] = (uint8_t)((uint8_t)0xFF << (8 - bits)); // Set first bits.
 936          network.m_addr[i] &= netmask[i]; // Normalize network according to netmask.
 937          n -= bits;
 938      }
 939  }
 940  
 941  /**
 942   * @returns The number of 1-bits in the prefix of the specified subnet mask. If
 943   *          the specified subnet mask is not a valid one, -1.
 944   */
 945  static inline int NetmaskBits(uint8_t x)
 946  {
 947      switch(x) {
 948      case 0x00: return 0;
 949      case 0x80: return 1;
 950      case 0xc0: return 2;
 951      case 0xe0: return 3;
 952      case 0xf0: return 4;
 953      case 0xf8: return 5;
 954      case 0xfc: return 6;
 955      case 0xfe: return 7;
 956      case 0xff: return 8;
 957      default: return -1;
 958      }
 959  }
 960  
 961  CSubNet::CSubNet(const CNetAddr& addr, const CNetAddr& mask) : CSubNet()
 962  {
 963      valid = (addr.IsIPv4() || addr.IsIPv6()) && addr.m_net == mask.m_net;
 964      if (!valid) {
 965          return;
 966      }
 967      // Check if `mask` contains 1-bits after 0-bits (which is an invalid netmask).
 968      bool zeros_found = false;
 969      for (auto b : mask.m_addr) {
 970          const int num_bits = NetmaskBits(b);
 971          if (num_bits == -1 || (zeros_found && num_bits != 0)) {
 972              valid = false;
 973              return;
 974          }
 975          if (num_bits < 8) {
 976              zeros_found = true;
 977          }
 978      }
 979  
 980      assert(mask.m_addr.size() <= sizeof(netmask));
 981  
 982      memcpy(netmask, mask.m_addr.data(), mask.m_addr.size());
 983  
 984      network = addr;
 985  
 986      // Normalize network according to netmask
 987      for (size_t x = 0; x < network.m_addr.size(); ++x) {
 988          network.m_addr[x] &= netmask[x];
 989      }
 990  }
 991  
 992  CSubNet::CSubNet(const CNetAddr& addr) : CSubNet()
 993  {
 994      switch (addr.m_net) {
 995      case NET_IPV4:
 996      case NET_IPV6:
 997          valid = true;
 998          assert(addr.m_addr.size() <= sizeof(netmask));
 999          memset(netmask, 0xFF, addr.m_addr.size());
1000          break;
1001      case NET_ONION:
1002      case NET_I2P:
1003      case NET_CJDNS:
1004          valid = true;
1005          break;
1006      case NET_INTERNAL:
1007      case NET_UNROUTABLE:
1008      case NET_MAX:
1009          return;
1010      }
1011  
1012      network = addr;
1013  }
1014  
1015  /**
1016   * @returns True if this subnet is valid, the specified address is valid, and
1017   *          the specified address belongs in this subnet.
1018   */
1019  bool CSubNet::Match(const CNetAddr &addr) const
1020  {
1021      if (!valid || !addr.IsValid() || network.m_net != addr.m_net)
1022          return false;
1023  
1024      switch (network.m_net) {
1025      case NET_IPV4:
1026      case NET_IPV6:
1027          break;
1028      case NET_ONION:
1029      case NET_I2P:
1030      case NET_CJDNS:
1031      case NET_INTERNAL:
1032          return addr == network;
1033      case NET_UNROUTABLE:
1034      case NET_MAX:
1035          return false;
1036      }
1037  
1038      assert(network.m_addr.size() == addr.m_addr.size());
1039      for (size_t x = 0; x < addr.m_addr.size(); ++x) {
1040          if ((addr.m_addr[x] & netmask[x]) != network.m_addr[x]) {
1041              return false;
1042          }
1043      }
1044      return true;
1045  }
1046  
1047  std::string CSubNet::ToString() const
1048  {
1049      std::string suffix;
1050  
1051      switch (network.m_net) {
1052      case NET_IPV4:
1053      case NET_IPV6: {
1054          assert(network.m_addr.size() <= sizeof(netmask));
1055  
1056          uint8_t cidr = 0;
1057  
1058          for (size_t i = 0; i < network.m_addr.size(); ++i) {
1059              if (netmask[i] == 0x00) {
1060                  break;
1061              }
1062              cidr += NetmaskBits(netmask[i]);
1063          }
1064  
1065          suffix = strprintf("/%u", cidr);
1066          break;
1067      }
1068      case NET_ONION:
1069      case NET_I2P:
1070      case NET_CJDNS:
1071      case NET_INTERNAL:
1072      case NET_UNROUTABLE:
1073      case NET_MAX:
1074          break;
1075      }
1076  
1077      return network.ToStringAddr() + suffix;
1078  }
1079  
1080  bool CSubNet::IsValid() const
1081  {
1082      return valid;
1083  }
1084  
1085  bool operator==(const CSubNet& a, const CSubNet& b)
1086  {
1087      return a.valid == b.valid && a.network == b.network && !memcmp(a.netmask, b.netmask, 16);
1088  }
1089  
1090  bool operator<(const CSubNet& a, const CSubNet& b)
1091  {
1092      return (a.network < b.network || (a.network == b.network && memcmp(a.netmask, b.netmask, 16) < 0));
1093  }