src/netaddress.cpp

   1 // Copyright (c) 2009-2010 Satoshi Nakamoto
   2 // Copyright (c) 2009-2017 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 #include <hash.h>
   8 #include <utilstrencodings.h>
   9 #include <tinyformat.h>
  10
  11 static const unsigned char pchIPv4[12] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff };
  12 static const unsigned char pchOnionCat[] = {0xFD,0x87,0xD8,0x7E,0xEB,0x43};
  13
  14 // 0xFD + sha256("bitcoin")[0:5]
  15 static const unsigned char g_internal_prefix[] = { 0xFD, 0x6B, 0x88, 0xC0, 0x87, 0x24 };
  16
  17 void CNetAddr::Init()
  18 {
  19     memset(ip, 0, sizeof(ip));
  20     scopeId = 0;
  21 }
  22
  23 void CNetAddr::SetIP(const CNetAddr& ipIn)
  24 {
  25     memcpy(ip, ipIn.ip, sizeof(ip));
  26 }
  27
  28 void CNetAddr::SetRaw(Network network, const uint8_t *ip_in)
  29 {
  30     switch(network)
  31     {
  32         case NET_IPV4:
  33             memcpy(ip, pchIPv4, 12);
  34             memcpy(ip+12, ip_in, 4);
  35             break;
  36         case NET_IPV6:
  37             memcpy(ip, ip_in, 16);
  38             break;
  39         default:
  40             assert(!"invalid network");
  41     }
  42 }
  43
  44 bool CNetAddr::SetInternal(const std::string &name)
  45 {
  46     if (name.empty()) {
  47         return false;
  48     }
  49     unsigned char hash[32] = {};
  50     CSHA256().Write((const unsigned char*)name.data(), name.size()).Finalize(hash);
  51     memcpy(ip, g_internal_prefix, sizeof(g_internal_prefix));
  52     memcpy(ip + sizeof(g_internal_prefix), hash, sizeof(ip) - sizeof(g_internal_prefix));
  53     return true;
  54 }
  55
  56 bool CNetAddr::SetSpecial(const std::string &strName)
  57 {
  58     if (strName.size()>6 && strName.substr(strName.size() - 6, 6) == ".onion") {
  59         std::vector<unsigned char> vchAddr = DecodeBase32(strName.substr(0, strName.size() - 6).c_str());
  60         if (vchAddr.size() != 16-sizeof(pchOnionCat))
  61             return false;
  62         memcpy(ip, pchOnionCat, sizeof(pchOnionCat));
  63         for (unsigned int i=0; i<16-sizeof(pchOnionCat); i++)
  64             ip[i + sizeof(pchOnionCat)] = vchAddr[i];
  65         return true;
  66     }
  67     return false;
  68 }
  69
  70 CNetAddr::CNetAddr()
  71 {
  72     Init();
  73 }
  74
  75 CNetAddr::CNetAddr(const struct in_addr& ipv4Addr)
  76 {
  77     SetRaw(NET_IPV4, (const uint8_t*)&ipv4Addr);
  78 }
  79
  80 CNetAddr::CNetAddr(const struct in6_addr& ipv6Addr, const uint32_t scope)
  81 {
  82     SetRaw(NET_IPV6, (const uint8_t*)&ipv6Addr);
  83     scopeId = scope;
  84 }
  85
  86 unsigned int CNetAddr::GetByte(int n) const
  87 {
  88     return ip[15-n];
  89 }
  90
  91 bool CNetAddr::IsIPv4() const
  92 {
  93     return (memcmp(ip, pchIPv4, sizeof(pchIPv4)) == 0);
  94 }
  95
  96 bool CNetAddr::IsIPv6() const
  97 {
  98     return (!IsIPv4() && !IsTor() && !IsInternal());
  99 }
 100
 101 bool CNetAddr::IsRFC1918() const
 102 {
 103     return IsIPv4() && (
 104         GetByte(3) == 10 ||
 105         (GetByte(3) == 192 && GetByte(2) == 168) ||
 106         (GetByte(3) == 172 && (GetByte(2) >= 16 && GetByte(2) <= 31)));
 107 }
 108
 109 bool CNetAddr::IsRFC2544() const
 110 {
 111     return IsIPv4() && GetByte(3) == 198 && (GetByte(2) == 18 || GetByte(2) == 19);
 112 }
 113
 114 bool CNetAddr::IsRFC3927() const
 115 {
 116     return IsIPv4() && (GetByte(3) == 169 && GetByte(2) == 254);
 117 }
 118
 119 bool CNetAddr::IsRFC6598() const
 120 {
 121     return IsIPv4() && GetByte(3) == 100 && GetByte(2) >= 64 && GetByte(2) <= 127;
 122 }
 123
 124 bool CNetAddr::IsRFC5737() const
 125 {
 126     return IsIPv4() && ((GetByte(3) == 192 && GetByte(2) == 0 && GetByte(1) == 2) ||
 127         (GetByte(3) == 198 && GetByte(2) == 51 && GetByte(1) == 100) ||
 128         (GetByte(3) == 203 && GetByte(2) == 0 && GetByte(1) == 113));
 129 }
 130
 131 bool CNetAddr::IsRFC3849() const
 132 {
 133     return GetByte(15) == 0x20 && GetByte(14) == 0x01 && GetByte(13) == 0x0D && GetByte(12) == 0xB8;
 134 }
 135
 136 bool CNetAddr::IsRFC3964() const
 137 {
 138     return (GetByte(15) == 0x20 && GetByte(14) == 0x02);
 139 }
 140
 141 bool CNetAddr::IsRFC6052() const
 142 {
 143     static const unsigned char pchRFC6052[] = {0,0x64,0xFF,0x9B,0,0,0,0,0,0,0,0};
 144     return (memcmp(ip, pchRFC6052, sizeof(pchRFC6052)) == 0);
 145 }
 146
 147 bool CNetAddr::IsRFC4380() const
 148 {
 149     return (GetByte(15) == 0x20 && GetByte(14) == 0x01 && GetByte(13) == 0 && GetByte(12) == 0);
 150 }
 151
 152 bool CNetAddr::IsRFC4862() const
 153 {
 154     static const unsigned char pchRFC4862[] = {0xFE,0x80,0,0,0,0,0,0};
 155     return (memcmp(ip, pchRFC4862, sizeof(pchRFC4862)) == 0);
 156 }
 157
 158 bool CNetAddr::IsRFC4193() const
 159 {
 160     return ((GetByte(15) & 0xFE) == 0xFC);
 161 }
 162
 163 bool CNetAddr::IsRFC6145() const
 164 {
 165     static const unsigned char pchRFC6145[] = {0,0,0,0,0,0,0,0,0xFF,0xFF,0,0};
 166     return (memcmp(ip, pchRFC6145, sizeof(pchRFC6145)) == 0);
 167 }
 168
 169 bool CNetAddr::IsRFC4843() const
 170 {
 171     return (GetByte(15) == 0x20 && GetByte(14) == 0x01 && GetByte(13) == 0x00 && (GetByte(12) & 0xF0) == 0x10);
 172 }
 173
 174 bool CNetAddr::IsTor() const
 175 {
 176     return (memcmp(ip, pchOnionCat, sizeof(pchOnionCat)) == 0);
 177 }
 178
 179 bool CNetAddr::IsLocal() const
 180 {
 181     // IPv4 loopback
 182    if (IsIPv4() && (GetByte(3) == 127 || GetByte(3) == 0))
 183        return true;
 184
 185    // IPv6 loopback (::1/128)
 186    static const unsigned char pchLocal[16] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
 187    if (memcmp(ip, pchLocal, 16) == 0)
 188        return true;
 189
 190    return false;
 191 }
 192
 193 bool CNetAddr::IsValid() const
 194 {
 195     // Cleanup 3-byte shifted addresses caused by garbage in size field
 196     // of addr messages from versions before 0.2.9 checksum.
 197     // Two consecutive addr messages look like this:
 198     // header20 vectorlen3 addr26 addr26 addr26 header20 vectorlen3 addr26 addr26 addr26...
 199     // so if the first length field is garbled, it reads the second batch
 200     // of addr misaligned by 3 bytes.
 201     if (memcmp(ip, pchIPv4+3, sizeof(pchIPv4)-3) == 0)
 202         return false;
 203
 204     // unspecified IPv6 address (::/128)
 205     unsigned char ipNone6[16] = {};
 206     if (memcmp(ip, ipNone6, 16) == 0)
 207         return false;
 208
 209     // documentation IPv6 address
 210     if (IsRFC3849())
 211         return false;
 212
 213     if (IsInternal())
 214         return false;
 215
 216     if (IsIPv4())
 217     {
 218         // INADDR_NONE
 219         uint32_t ipNone = INADDR_NONE;
 220         if (memcmp(ip+12, &ipNone, 4) == 0)
 221             return false;
 222
 223         // 0
 224         ipNone = 0;
 225         if (memcmp(ip+12, &ipNone, 4) == 0)
 226             return false;
 227     }
 228
 229     return true;
 230 }
 231
 232 bool CNetAddr::IsRoutable() const
 233 {
 234     return IsValid() && !(IsRFC1918() || IsRFC2544() || IsRFC3927() || IsRFC4862() || IsRFC6598() || IsRFC5737() || (IsRFC4193() && !IsTor()) || IsRFC4843() || IsLocal() || IsInternal());
 235 }
 236
 237 bool CNetAddr::IsInternal() const
 238 {
 239    return memcmp(ip, g_internal_prefix, sizeof(g_internal_prefix)) == 0;
 240 }
 241
 242 enum Network CNetAddr::GetNetwork() const
 243 {
 244     if (IsInternal())
 245         return NET_INTERNAL;
 246
 247     if (!IsRoutable())
 248         return NET_UNROUTABLE;
 249
 250     if (IsIPv4())
 251         return NET_IPV4;
 252
 253     if (IsTor())
 254         return NET_TOR;
 255
 256     return NET_IPV6;
 257 }
 258
 259 std::string CNetAddr::ToStringIP() const
 260 {
 261     if (IsTor())
 262         return EncodeBase32(&ip[6], 10) + ".onion";
 263     if (IsInternal())
 264         return EncodeBase32(ip + sizeof(g_internal_prefix), sizeof(ip) - sizeof(g_internal_prefix)) + ".internal";
 265     CService serv(*this, 0);
 266     struct sockaddr_storage sockaddr;
 267     socklen_t socklen = sizeof(sockaddr);
 268     if (serv.GetSockAddr((struct sockaddr*)&sockaddr, &socklen)) {
 269         char name[1025] = "";
 270         if (!getnameinfo((const struct sockaddr*)&sockaddr, socklen, name, sizeof(name), nullptr, 0, NI_NUMERICHOST))
 271             return std::string(name);
 272     }
 273     if (IsIPv4())
 274         return strprintf("%u.%u.%u.%u", GetByte(3), GetByte(2), GetByte(1), GetByte(0));
 275     else
 276         return strprintf("%x:%x:%x:%x:%x:%x:%x:%x",
 277                          GetByte(15) << 8 | GetByte(14), GetByte(13) << 8 | GetByte(12),
 278                          GetByte(11) << 8 | GetByte(10), GetByte(9) << 8 | GetByte(8),
 279                          GetByte(7) << 8 | GetByte(6), GetByte(5) << 8 | GetByte(4),
 280                          GetByte(3) << 8 | GetByte(2), GetByte(1) << 8 | GetByte(0));
 281 }
 282
 283 std::string CNetAddr::ToString() const
 284 {
 285     return ToStringIP();
 286 }
 287
 288 bool operator==(const CNetAddr& a, const CNetAddr& b)
 289 {
 290     return (memcmp(a.ip, b.ip, 16) == 0);
 291 }
 292
 293 bool operator!=(const CNetAddr& a, const CNetAddr& b)
 294 {
 295     return (memcmp(a.ip, b.ip, 16) != 0);
 296 }
 297
 298 bool operator<(const CNetAddr& a, const CNetAddr& b)
 299 {
 300     return (memcmp(a.ip, b.ip, 16) < 0);
 301 }
 302
 303 bool CNetAddr::GetInAddr(struct in_addr* pipv4Addr) const
 304 {
 305     if (!IsIPv4())
 306         return false;
 307     memcpy(pipv4Addr, ip+12, 4);
 308     return true;
 309 }
 310
 311 bool CNetAddr::GetIn6Addr(struct in6_addr* pipv6Addr) const
 312 {
 313     memcpy(pipv6Addr, ip, 16);
 314     return true;
 315 }
 316
 317 // get canonical identifier of an address' group
 318 // no two connections will be attempted to addresses with the same group
 319 std::vector<unsigned char> CNetAddr::GetGroup() const
 320 {
 321     std::vector<unsigned char> vchRet;
 322     int nClass = NET_IPV6;
 323     int nStartByte = 0;
 324     int nBits = 16;
 325
 326     // all local addresses belong to the same group
 327     if (IsLocal())
 328     {
 329         nClass = 255;
 330         nBits = 0;
 331     }
 332     // all internal-usage addresses get their own group
 333     if (IsInternal())
 334     {
 335         nClass = NET_INTERNAL;
 336         nStartByte = sizeof(g_internal_prefix);
 337         nBits = (sizeof(ip) - sizeof(g_internal_prefix)) * 8;
 338     }
 339     // all other unroutable addresses belong to the same group
 340     else if (!IsRoutable())
 341     {
 342         nClass = NET_UNROUTABLE;
 343         nBits = 0;
 344     }
 345     // for IPv4 addresses, '1' + the 16 higher-order bits of the IP
 346     // includes mapped IPv4, SIIT translated IPv4, and the well-known prefix
 347     else if (IsIPv4() || IsRFC6145() || IsRFC6052())
 348     {
 349         nClass = NET_IPV4;
 350         nStartByte = 12;
 351     }
 352     // for 6to4 tunnelled addresses, use the encapsulated IPv4 address
 353     else if (IsRFC3964())
 354     {
 355         nClass = NET_IPV4;
 356         nStartByte = 2;
 357     }
 358     // for Teredo-tunnelled IPv6 addresses, use the encapsulated IPv4 address
 359     else if (IsRFC4380())
 360     {
 361         vchRet.push_back(NET_IPV4);
 362         vchRet.push_back(GetByte(3) ^ 0xFF);
 363         vchRet.push_back(GetByte(2) ^ 0xFF);
 364         return vchRet;
 365     }
 366     else if (IsTor())
 367     {
 368         nClass = NET_TOR;
 369         nStartByte = 6;
 370         nBits = 4;
 371     }
 372     // for he.net, use /36 groups
 373     else if (GetByte(15) == 0x20 && GetByte(14) == 0x01 && GetByte(13) == 0x04 && GetByte(12) == 0x70)
 374         nBits = 36;
 375     // for the rest of the IPv6 network, use /32 groups
 376     else
 377         nBits = 32;
 378
 379     vchRet.push_back(nClass);
 380     while (nBits >= 8)
 381     {
 382         vchRet.push_back(GetByte(15 - nStartByte));
 383         nStartByte++;
 384         nBits -= 8;
 385     }
 386     if (nBits > 0)
 387         vchRet.push_back(GetByte(15 - nStartByte) | ((1 << (8 - nBits)) - 1));
 388
 389     return vchRet;
 390 }
 391
 392 uint64_t CNetAddr::GetHash() const
 393 {
 394     uint256 hash = Hash(&ip[0], &ip[16]);
 395     uint64_t nRet;
 396     memcpy(&nRet, &hash, sizeof(nRet));
 397     return nRet;
 398 }
 399
 400 // private extensions to enum Network, only returned by GetExtNetwork,
 401 // and only used in GetReachabilityFrom
 402 static const int NET_UNKNOWN = NET_MAX + 0;
 403 static const int NET_TEREDO  = NET_MAX + 1;
 404 int static GetExtNetwork(const CNetAddr *addr)
 405 {
 406     if (addr == nullptr)
 407         return NET_UNKNOWN;
 408     if (addr->IsRFC4380())
 409         return NET_TEREDO;
 410     return addr->GetNetwork();
 411 }
 412
 413 /** Calculates a metric for how reachable (*this) is from a given partner */
 414 int CNetAddr::GetReachabilityFrom(const CNetAddr *paddrPartner) const
 415 {
 416     enum Reachability {
 417         REACH_UNREACHABLE,
 418         REACH_DEFAULT,
 419         REACH_TEREDO,
 420         REACH_IPV6_WEAK,
 421         REACH_IPV4,
 422         REACH_IPV6_STRONG,
 423         REACH_PRIVATE
 424     };
 425
 426     if (!IsRoutable() || IsInternal())
 427         return REACH_UNREACHABLE;
 428
 429     int ourNet = GetExtNetwork(this);
 430     int theirNet = GetExtNetwork(paddrPartner);
 431     bool fTunnel = IsRFC3964() || IsRFC6052() || IsRFC6145();
 432
 433     switch(theirNet) {
 434     case NET_IPV4:
 435         switch(ourNet) {
 436         default:       return REACH_DEFAULT;
 437         case NET_IPV4: return REACH_IPV4;
 438         }
 439     case NET_IPV6:
 440         switch(ourNet) {
 441         default:         return REACH_DEFAULT;
 442         case NET_TEREDO: return REACH_TEREDO;
 443         case NET_IPV4:   return REACH_IPV4;
 444         case NET_IPV6:   return fTunnel ? REACH_IPV6_WEAK : REACH_IPV6_STRONG; // only prefer giving our IPv6 address if it's not tunnelled
 445         }
 446     case NET_TOR:
 447         switch(ourNet) {
 448         default:         return REACH_DEFAULT;
 449         case NET_IPV4:   return REACH_IPV4; // Tor users can connect to IPv4 as well
 450         case NET_TOR:    return REACH_PRIVATE;
 451         }
 452     case NET_TEREDO:
 453         switch(ourNet) {
 454         default:          return REACH_DEFAULT;
 455         case NET_TEREDO:  return REACH_TEREDO;
 456         case NET_IPV6:    return REACH_IPV6_WEAK;
 457         case NET_IPV4:    return REACH_IPV4;
 458         }
 459     case NET_UNKNOWN:
 460     case NET_UNROUTABLE:
 461     default:
 462         switch(ourNet) {
 463         default:          return REACH_DEFAULT;
 464         case NET_TEREDO:  return REACH_TEREDO;
 465         case NET_IPV6:    return REACH_IPV6_WEAK;
 466         case NET_IPV4:    return REACH_IPV4;
 467         case NET_TOR:     return REACH_PRIVATE; // either from Tor, or don't care about our address
 468         }
 469     }
 470 }
 471
 472 void CService::Init()
 473 {
 474     port = 0;
 475 }
 476
 477 CService::CService()
 478 {
 479     Init();
 480 }
 481
 482 CService::CService(const CNetAddr& cip, unsigned short portIn) : CNetAddr(cip), port(portIn)
 483 {
 484 }
 485
 486 CService::CService(const struct in_addr& ipv4Addr, unsigned short portIn) : CNetAddr(ipv4Addr), port(portIn)
 487 {
 488 }
 489
 490 CService::CService(const struct in6_addr& ipv6Addr, unsigned short portIn) : CNetAddr(ipv6Addr), port(portIn)
 491 {
 492 }
 493
 494 CService::CService(const struct sockaddr_in& addr) : CNetAddr(addr.sin_addr), port(ntohs(addr.sin_port))
 495 {
 496     assert(addr.sin_family == AF_INET);
 497 }
 498
 499 CService::CService(const struct sockaddr_in6 &addr) : CNetAddr(addr.sin6_addr, addr.sin6_scope_id), port(ntohs(addr.sin6_port))
 500 {
 501    assert(addr.sin6_family == AF_INET6);
 502 }
 503
 504 bool CService::SetSockAddr(const struct sockaddr *paddr)
 505 {
 506     switch (paddr->sa_family) {
 507     case AF_INET:
 508         *this = CService(*(const struct sockaddr_in*)paddr);
 509         return true;
 510     case AF_INET6:
 511         *this = CService(*(const struct sockaddr_in6*)paddr);
 512         return true;
 513     default:
 514         return false;
 515     }
 516 }
 517
 518 unsigned short CService::GetPort() const
 519 {
 520     return port;
 521 }
 522
 523 bool operator==(const CService& a, const CService& b)
 524 {
 525     return (CNetAddr)a == (CNetAddr)b && a.port == b.port;
 526 }
 527
 528 bool operator!=(const CService& a, const CService& b)
 529 {
 530     return (CNetAddr)a != (CNetAddr)b || a.port != b.port;
 531 }
 532
 533 bool operator<(const CService& a, const CService& b)
 534 {
 535     return (CNetAddr)a < (CNetAddr)b || ((CNetAddr)a == (CNetAddr)b && a.port < b.port);
 536 }
 537
 538 bool CService::GetSockAddr(struct sockaddr* paddr, socklen_t *addrlen) const
 539 {
 540     if (IsIPv4()) {
 541         if (*addrlen < (socklen_t)sizeof(struct sockaddr_in))
 542             return false;
 543         *addrlen = sizeof(struct sockaddr_in);
 544         struct sockaddr_in *paddrin = (struct sockaddr_in*)paddr;
 545         memset(paddrin, 0, *addrlen);
 546         if (!GetInAddr(&paddrin->sin_addr))
 547             return false;
 548         paddrin->sin_family = AF_INET;
 549         paddrin->sin_port = htons(port);
 550         return true;
 551     }
 552     if (IsIPv6()) {
 553         if (*addrlen < (socklen_t)sizeof(struct sockaddr_in6))
 554             return false;
 555         *addrlen = sizeof(struct sockaddr_in6);
 556         struct sockaddr_in6 *paddrin6 = (struct sockaddr_in6*)paddr;
 557         memset(paddrin6, 0, *addrlen);
 558         if (!GetIn6Addr(&paddrin6->sin6_addr))
 559             return false;
 560         paddrin6->sin6_scope_id = scopeId;
 561         paddrin6->sin6_family = AF_INET6;
 562         paddrin6->sin6_port = htons(port);
 563         return true;
 564     }
 565     return false;
 566 }
 567
 568 std::vector<unsigned char> CService::GetKey() const
 569 {
 570      std::vector<unsigned char> vKey;
 571      vKey.resize(18);
 572      memcpy(vKey.data(), ip, 16);
 573      vKey[16] = port / 0x100;
 574      vKey[17] = port & 0x0FF;
 575      return vKey;
 576 }
 577
 578 std::string CService::ToStringPort() const
 579 {
 580     return strprintf("%u", port);
 581 }
 582
 583 std::string CService::ToStringIPPort() const
 584 {
 585     if (IsIPv4() || IsTor() || IsInternal()) {
 586         return ToStringIP() + ":" + ToStringPort();
 587     } else {
 588         return "[" + ToStringIP() + "]:" + ToStringPort();
 589     }
 590 }
 591
 592 std::string CService::ToString() const
 593 {
 594     return ToStringIPPort();
 595 }
 596
 597 CSubNet::CSubNet():
 598     valid(false)
 599 {
 600     memset(netmask, 0, sizeof(netmask));
 601 }
 602
 603 CSubNet::CSubNet(const CNetAddr &addr, int32_t mask)
 604 {
 605     valid = true;
 606     network = addr;
 607     // Default to /32 (IPv4) or /128 (IPv6), i.e. match single address
 608     memset(netmask, 255, sizeof(netmask));
 609
 610     // IPv4 addresses start at offset 12, and first 12 bytes must match, so just offset n
 611     const int astartofs = network.IsIPv4() ? 12 : 0;
 612
 613     int32_t n = mask;
 614     if(n >= 0 && n <= (128 - astartofs*8)) // Only valid if in range of bits of address
 615     {
 616         n += astartofs*8;
 617         // Clear bits [n..127]
 618         for (; n < 128; ++n)
 619             netmask[n>>3] &= ~(1<<(7-(n&7)));
 620     } else
 621         valid = false;
 622
 623     // Normalize network according to netmask
 624     for(int x=0; x<16; ++x)
 625         network.ip[x] &= netmask[x];
 626 }
 627
 628 CSubNet::CSubNet(const CNetAddr &addr, const CNetAddr &mask)
 629 {
 630     valid = true;
 631     network = addr;
 632     // Default to /32 (IPv4) or /128 (IPv6), i.e. match single address
 633     memset(netmask, 255, sizeof(netmask));
 634
 635     // IPv4 addresses start at offset 12, and first 12 bytes must match, so just offset n
 636     const int astartofs = network.IsIPv4() ? 12 : 0;
 637
 638     for(int x=astartofs; x<16; ++x)
 639         netmask[x] = mask.ip[x];
 640
 641     // Normalize network according to netmask
 642     for(int x=0; x<16; ++x)
 643         network.ip[x] &= netmask[x];
 644 }
 645
 646 CSubNet::CSubNet(const CNetAddr &addr):
 647     valid(addr.IsValid())
 648 {
 649     memset(netmask, 255, sizeof(netmask));
 650     network = addr;
 651 }
 652
 653 bool CSubNet::Match(const CNetAddr &addr) const
 654 {
 655     if (!valid || !addr.IsValid())
 656         return false;
 657     for(int x=0; x<16; ++x)
 658         if ((addr.ip[x] & netmask[x]) != network.ip[x])
 659             return false;
 660     return true;
 661 }
 662
 663 static inline int NetmaskBits(uint8_t x)
 664 {
 665     switch(x) {
 666     case 0x00: return 0; break;
 667     case 0x80: return 1; break;
 668     case 0xc0: return 2; break;
 669     case 0xe0: return 3; break;
 670     case 0xf0: return 4; break;
 671     case 0xf8: return 5; break;
 672     case 0xfc: return 6; break;
 673     case 0xfe: return 7; break;
 674     case 0xff: return 8; break;
 675     default: return -1; break;
 676     }
 677 }
 678
 679 std::string CSubNet::ToString() const
 680 {
 681     /* Parse binary 1{n}0{N-n} to see if mask can be represented as /n */
 682     int cidr = 0;
 683     bool valid_cidr = true;
 684     int n = network.IsIPv4() ? 12 : 0;
 685     for (; n < 16 && netmask[n] == 0xff; ++n)
 686         cidr += 8;
 687     if (n < 16) {
 688         int bits = NetmaskBits(netmask[n]);
 689         if (bits < 0)
 690             valid_cidr = false;
 691         else
 692             cidr += bits;
 693         ++n;
 694     }
 695     for (; n < 16 && valid_cidr; ++n)
 696         if (netmask[n] != 0x00)
 697             valid_cidr = false;
 698
 699     /* Format output */
 700     std::string strNetmask;
 701     if (valid_cidr) {
 702         strNetmask = strprintf("%u", cidr);
 703     } else {
 704         if (network.IsIPv4())
 705             strNetmask = strprintf("%u.%u.%u.%u", netmask[12], netmask[13], netmask[14], netmask[15]);
 706         else
 707             strNetmask = strprintf("%x:%x:%x:%x:%x:%x:%x:%x",
 708                              netmask[0] << 8 | netmask[1], netmask[2] << 8 | netmask[3],
 709                              netmask[4] << 8 | netmask[5], netmask[6] << 8 | netmask[7],
 710                              netmask[8] << 8 | netmask[9], netmask[10] << 8 | netmask[11],
 711                              netmask[12] << 8 | netmask[13], netmask[14] << 8 | netmask[15]);
 712     }
 713
 714     return network.ToString() + "/" + strNetmask;
 715 }
 716
 717 bool CSubNet::IsValid() const
 718 {
 719     return valid;
 720 }
 721
 722 bool operator==(const CSubNet& a, const CSubNet& b)
 723 {
 724     return a.valid == b.valid && a.network == b.network && !memcmp(a.netmask, b.netmask, 16);
 725 }
 726
 727 bool operator!=(const CSubNet& a, const CSubNet& b)
 728 {
 729     return !(a==b);
 730 }
 731
 732 bool operator<(const CSubNet& a, const CSubNet& b)
 733 {
 734     return (a.network < b.network || (a.network == b.network && memcmp(a.netmask, b.netmask, 16) < 0));
 735 }