src/netaddress.cpp

   1 // Copyright (c) 2009-2010 Satoshi Nakamoto
   2 // Copyright (c) 2009-2016 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 #ifdef HAVE_CONFIG_H
   7 #include "config/bitcoin-config.h"
   8 #endif
   9
  10 #include "netaddress.h"
  11 #include "hash.h"
  12 #include "utilstrencodings.h"
  13 #include "tinyformat.h"
  14
  15 static const unsigned char pchIPv4[12] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff };
  16 static const unsigned char pchOnionCat[] = {0xFD,0x87,0xD8,0x7E,0xEB,0x43};
  17
  18 void CNetAddr::Init()
  19 {
  20     memset(ip, 0, sizeof(ip));
  21     scopeId = 0;
  22 }
  23
  24 void CNetAddr::SetIP(const CNetAddr& ipIn)
  25 {
  26     memcpy(ip, ipIn.ip, sizeof(ip));
  27 }
  28
  29 void CNetAddr::SetRaw(Network network, const uint8_t *ip_in)
  30 {
  31     switch(network)
  32     {
  33         case NET_IPV4:
  34             memcpy(ip, pchIPv4, 12);
  35             memcpy(ip+12, ip_in, 4);
  36             break;
  37         case NET_IPV6:
  38             memcpy(ip, ip_in, 16);
  39             break;
  40         default:
  41             assert(!"invalid network");
  42     }
  43 }
  44
  45 bool CNetAddr::SetSpecial(const std::string &strName)
  46 {
  47     if (strName.size()>6 && strName.substr(strName.size() - 6, 6) == ".onion") {
  48         std::vector<unsigned char> vchAddr = DecodeBase32(strName.substr(0, strName.size() - 6).c_str());
  49         if (vchAddr.size() != 16-sizeof(pchOnionCat))
  50             return false;
  51         memcpy(ip, pchOnionCat, sizeof(pchOnionCat));
  52         for (unsigned int i=0; i<16-sizeof(pchOnionCat); i++)
  53             ip[i + sizeof(pchOnionCat)] = vchAddr[i];
  54         return true;
  55     }
  56     return false;
  57 }
  58
  59 CNetAddr::CNetAddr()
  60 {
  61     Init();
  62 }
  63
  64 CNetAddr::CNetAddr(const struct in_addr& ipv4Addr)
  65 {
  66     SetRaw(NET_IPV4, (const uint8_t*)&ipv4Addr);
  67 }
  68
  69 CNetAddr::CNetAddr(const struct in6_addr& ipv6Addr, const uint32_t scope)
  70 {
  71     SetRaw(NET_IPV6, (const uint8_t*)&ipv6Addr);
  72     scopeId = scope;
  73 }
  74
  75 unsigned int CNetAddr::GetByte(int n) const
  76 {
  77     return ip[15-n];
  78 }
  79
  80 bool CNetAddr::IsIPv4() const
  81 {
  82     return (memcmp(ip, pchIPv4, sizeof(pchIPv4)) == 0);
  83 }
  84
  85 bool CNetAddr::IsIPv6() const
  86 {
  87     return (!IsIPv4() && !IsTor());
  88 }
  89
  90 bool CNetAddr::IsRFC1918() const
  91 {
  92     return IsIPv4() && (
  93         GetByte(3) == 10 ||
  94         (GetByte(3) == 192 && GetByte(2) == 168) ||
  95         (GetByte(3) == 172 && (GetByte(2) >= 16 && GetByte(2) <= 31)));
  96 }
  97
  98 bool CNetAddr::IsRFC2544() const
  99 {
 100     return IsIPv4() && GetByte(3) == 198 && (GetByte(2) == 18 || GetByte(2) == 19);
 101 }
 102
 103 bool CNetAddr::IsRFC3927() const
 104 {
 105     return IsIPv4() && (GetByte(3) == 169 && GetByte(2) == 254);
 106 }
 107
 108 bool CNetAddr::IsRFC6598() const
 109 {
 110     return IsIPv4() && GetByte(3) == 100 && GetByte(2) >= 64 && GetByte(2) <= 127;
 111 }
 112
 113 bool CNetAddr::IsRFC5737() const
 114 {
 115     return IsIPv4() && ((GetByte(3) == 192 && GetByte(2) == 0 && GetByte(1) == 2) ||
 116         (GetByte(3) == 198 && GetByte(2) == 51 && GetByte(1) == 100) ||
 117         (GetByte(3) == 203 && GetByte(2) == 0 && GetByte(1) == 113));
 118 }
 119
 120 bool CNetAddr::IsRFC3849() const
 121 {
 122     return GetByte(15) == 0x20 && GetByte(14) == 0x01 && GetByte(13) == 0x0D && GetByte(12) == 0xB8;
 123 }
 124
 125 bool CNetAddr::IsRFC3964() const
 126 {
 127     return (GetByte(15) == 0x20 && GetByte(14) == 0x02);
 128 }
 129
 130 bool CNetAddr::IsRFC6052() const
 131 {
 132     static const unsigned char pchRFC6052[] = {0,0x64,0xFF,0x9B,0,0,0,0,0,0,0,0};
 133     return (memcmp(ip, pchRFC6052, sizeof(pchRFC6052)) == 0);
 134 }
 135
 136 bool CNetAddr::IsRFC4380() const
 137 {
 138     return (GetByte(15) == 0x20 && GetByte(14) == 0x01 && GetByte(13) == 0 && GetByte(12) == 0);
 139 }
 140
 141 bool CNetAddr::IsRFC4862() const
 142 {
 143     static const unsigned char pchRFC4862[] = {0xFE,0x80,0,0,0,0,0,0};
 144     return (memcmp(ip, pchRFC4862, sizeof(pchRFC4862)) == 0);
 145 }
 146
 147 bool CNetAddr::IsRFC4193() const
 148 {
 149     return ((GetByte(15) & 0xFE) == 0xFC);
 150 }
 151
 152 bool CNetAddr::IsRFC6145() const
 153 {
 154     static const unsigned char pchRFC6145[] = {0,0,0,0,0,0,0,0,0xFF,0xFF,0,0};
 155     return (memcmp(ip, pchRFC6145, sizeof(pchRFC6145)) == 0);
 156 }
 157
 158 bool CNetAddr::IsRFC4843() const
 159 {
 160     return (GetByte(15) == 0x20 && GetByte(14) == 0x01 && GetByte(13) == 0x00 && (GetByte(12) & 0xF0) == 0x10);
 161 }
 162
 163 bool CNetAddr::IsTor() const
 164 {
 165     return (memcmp(ip, pchOnionCat, sizeof(pchOnionCat)) == 0);
 166 }
 167
 168 bool CNetAddr::IsLocal() const
 169 {
 170     // IPv4 loopback
 171    if (IsIPv4() && (GetByte(3) == 127 || GetByte(3) == 0))
 172        return true;
 173
 174    // IPv6 loopback (::1/128)
 175    static const unsigned char pchLocal[16] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
 176    if (memcmp(ip, pchLocal, 16) == 0)
 177        return true;
 178
 179    return false;
 180 }
 181
 182 bool CNetAddr::IsValid() const
 183 {
 184     // Cleanup 3-byte shifted addresses caused by garbage in size field
 185     // of addr messages from versions before 0.2.9 checksum.
 186     // Two consecutive addr messages look like this:
 187     // header20 vectorlen3 addr26 addr26 addr26 header20 vectorlen3 addr26 addr26 addr26...
 188     // so if the first length field is garbled, it reads the second batch
 189     // of addr misaligned by 3 bytes.
 190     if (memcmp(ip, pchIPv4+3, sizeof(pchIPv4)-3) == 0)
 191         return false;
 192
 193     // unspecified IPv6 address (::/128)
 194     unsigned char ipNone6[16] = {};
 195     if (memcmp(ip, ipNone6, 16) == 0)
 196         return false;
 197
 198     // documentation IPv6 address
 199     if (IsRFC3849())
 200         return false;
 201
 202     if (IsIPv4())
 203     {
 204         // INADDR_NONE
 205         uint32_t ipNone = INADDR_NONE;
 206         if (memcmp(ip+12, &ipNone, 4) == 0)
 207             return false;
 208
 209         // 0
 210         ipNone = 0;
 211         if (memcmp(ip+12, &ipNone, 4) == 0)
 212             return false;
 213     }
 214
 215     return true;
 216 }
 217
 218 bool CNetAddr::IsRoutable() const
 219 {
 220     return IsValid() && !(IsRFC1918() || IsRFC2544() || IsRFC3927() || IsRFC4862() || IsRFC6598() || IsRFC5737() || (IsRFC4193() && !IsTor()) || IsRFC4843() || IsLocal());
 221 }
 222
 223 enum Network CNetAddr::GetNetwork() const
 224 {
 225     if (!IsRoutable())
 226         return NET_UNROUTABLE;
 227
 228     if (IsIPv4())
 229         return NET_IPV4;
 230
 231     if (IsTor())
 232         return NET_TOR;
 233
 234     return NET_IPV6;
 235 }
 236
 237 std::string CNetAddr::ToStringIP() const
 238 {
 239     if (IsTor())
 240         return EncodeBase32(&ip[6], 10) + ".onion";
 241     CService serv(*this, 0);
 242     struct sockaddr_storage sockaddr;
 243     socklen_t socklen = sizeof(sockaddr);
 244     if (serv.GetSockAddr((struct sockaddr*)&sockaddr, &socklen)) {
 245         char name[1025] = "";
 246         if (!getnameinfo((const struct sockaddr*)&sockaddr, socklen, name, sizeof(name), NULL, 0, NI_NUMERICHOST))
 247             return std::string(name);
 248     }
 249     if (IsIPv4())
 250         return strprintf("%u.%u.%u.%u", GetByte(3), GetByte(2), GetByte(1), GetByte(0));
 251     else
 252         return strprintf("%x:%x:%x:%x:%x:%x:%x:%x",
 253                          GetByte(15) << 8 | GetByte(14), GetByte(13) << 8 | GetByte(12),
 254                          GetByte(11) << 8 | GetByte(10), GetByte(9) << 8 | GetByte(8),
 255                          GetByte(7) << 8 | GetByte(6), GetByte(5) << 8 | GetByte(4),
 256                          GetByte(3) << 8 | GetByte(2), GetByte(1) << 8 | GetByte(0));
 257 }
 258
 259 std::string CNetAddr::ToString() const
 260 {
 261     return ToStringIP();
 262 }
 263
 264 bool operator==(const CNetAddr& a, const CNetAddr& b)
 265 {
 266     return (memcmp(a.ip, b.ip, 16) == 0);
 267 }
 268
 269 bool operator!=(const CNetAddr& a, const CNetAddr& b)
 270 {
 271     return (memcmp(a.ip, b.ip, 16) != 0);
 272 }
 273
 274 bool operator<(const CNetAddr& a, const CNetAddr& b)
 275 {
 276     return (memcmp(a.ip, b.ip, 16) < 0);
 277 }
 278
 279 bool CNetAddr::GetInAddr(struct in_addr* pipv4Addr) const
 280 {
 281     if (!IsIPv4())
 282         return false;
 283     memcpy(pipv4Addr, ip+12, 4);
 284     return true;
 285 }
 286
 287 bool CNetAddr::GetIn6Addr(struct in6_addr* pipv6Addr) const
 288 {
 289     memcpy(pipv6Addr, ip, 16);
 290     return true;
 291 }
 292
 293 // get canonical identifier of an address' group
 294 // no two connections will be attempted to addresses with the same group
 295 std::vector<unsigned char> CNetAddr::GetGroup() const
 296 {
 297     std::vector<unsigned char> vchRet;
 298     int nClass = NET_IPV6;
 299     int nStartByte = 0;
 300     int nBits = 16;
 301
 302     // all local addresses belong to the same group
 303     if (IsLocal())
 304     {
 305         nClass = 255;
 306         nBits = 0;
 307     }
 308
 309     // all unroutable addresses belong to the same group
 310     if (!IsRoutable())
 311     {
 312         nClass = NET_UNROUTABLE;
 313         nBits = 0;
 314     }
 315     // for IPv4 addresses, '1' + the 16 higher-order bits of the IP
 316     // includes mapped IPv4, SIIT translated IPv4, and the well-known prefix
 317     else if (IsIPv4() || IsRFC6145() || IsRFC6052())
 318     {
 319         nClass = NET_IPV4;
 320         nStartByte = 12;
 321     }
 322     // for 6to4 tunnelled addresses, use the encapsulated IPv4 address
 323     else if (IsRFC3964())
 324     {
 325         nClass = NET_IPV4;
 326         nStartByte = 2;
 327     }
 328     // for Teredo-tunnelled IPv6 addresses, use the encapsulated IPv4 address
 329     else if (IsRFC4380())
 330     {
 331         vchRet.push_back(NET_IPV4);
 332         vchRet.push_back(GetByte(3) ^ 0xFF);
 333         vchRet.push_back(GetByte(2) ^ 0xFF);
 334         return vchRet;
 335     }
 336     else if (IsTor())
 337     {
 338         nClass = NET_TOR;
 339         nStartByte = 6;
 340         nBits = 4;
 341     }
 342     // for he.net, use /36 groups
 343     else if (GetByte(15) == 0x20 && GetByte(14) == 0x01 && GetByte(13) == 0x04 && GetByte(12) == 0x70)
 344         nBits = 36;
 345     // for the rest of the IPv6 network, use /32 groups
 346     else
 347         nBits = 32;
 348
 349     vchRet.push_back(nClass);
 350     while (nBits >= 8)
 351     {
 352         vchRet.push_back(GetByte(15 - nStartByte));
 353         nStartByte++;
 354         nBits -= 8;
 355     }
 356     if (nBits > 0)
 357         vchRet.push_back(GetByte(15 - nStartByte) | ((1 << (8 - nBits)) - 1));
 358
 359     return vchRet;
 360 }
 361
 362 uint64_t CNetAddr::GetHash() const
 363 {
 364     uint256 hash = Hash(&ip[0], &ip[16]);
 365     uint64_t nRet;
 366     memcpy(&nRet, &hash, sizeof(nRet));
 367     return nRet;
 368 }
 369
 370 // private extensions to enum Network, only returned by GetExtNetwork,
 371 // and only used in GetReachabilityFrom
 372 static const int NET_UNKNOWN = NET_MAX + 0;
 373 static const int NET_TEREDO  = NET_MAX + 1;
 374 int static GetExtNetwork(const CNetAddr *addr)
 375 {
 376     if (addr == NULL)
 377         return NET_UNKNOWN;
 378     if (addr->IsRFC4380())
 379         return NET_TEREDO;
 380     return addr->GetNetwork();
 381 }
 382
 383 /** Calculates a metric for how reachable (*this) is from a given partner */
 384 int CNetAddr::GetReachabilityFrom(const CNetAddr *paddrPartner) const
 385 {
 386     enum Reachability {
 387         REACH_UNREACHABLE,
 388         REACH_DEFAULT,
 389         REACH_TEREDO,
 390         REACH_IPV6_WEAK,
 391         REACH_IPV4,
 392         REACH_IPV6_STRONG,
 393         REACH_PRIVATE
 394     };
 395
 396     if (!IsRoutable())
 397         return REACH_UNREACHABLE;
 398
 399     int ourNet = GetExtNetwork(this);
 400     int theirNet = GetExtNetwork(paddrPartner);
 401     bool fTunnel = IsRFC3964() || IsRFC6052() || IsRFC6145();
 402
 403     switch(theirNet) {
 404     case NET_IPV4:
 405         switch(ourNet) {
 406         default:       return REACH_DEFAULT;
 407         case NET_IPV4: return REACH_IPV4;
 408         }
 409     case NET_IPV6:
 410         switch(ourNet) {
 411         default:         return REACH_DEFAULT;
 412         case NET_TEREDO: return REACH_TEREDO;
 413         case NET_IPV4:   return REACH_IPV4;
 414         case NET_IPV6:   return fTunnel ? REACH_IPV6_WEAK : REACH_IPV6_STRONG; // only prefer giving our IPv6 address if it's not tunnelled
 415         }
 416     case NET_TOR:
 417         switch(ourNet) {
 418         default:         return REACH_DEFAULT;
 419         case NET_IPV4:   return REACH_IPV4; // Tor users can connect to IPv4 as well
 420         case NET_TOR:    return REACH_PRIVATE;
 421         }
 422     case NET_TEREDO:
 423         switch(ourNet) {
 424         default:          return REACH_DEFAULT;
 425         case NET_TEREDO:  return REACH_TEREDO;
 426         case NET_IPV6:    return REACH_IPV6_WEAK;
 427         case NET_IPV4:    return REACH_IPV4;
 428         }
 429     case NET_UNKNOWN:
 430     case NET_UNROUTABLE:
 431     default:
 432         switch(ourNet) {
 433         default:          return REACH_DEFAULT;
 434         case NET_TEREDO:  return REACH_TEREDO;
 435         case NET_IPV6:    return REACH_IPV6_WEAK;
 436         case NET_IPV4:    return REACH_IPV4;
 437         case NET_TOR:     return REACH_PRIVATE; // either from Tor, or don't care about our address
 438         }
 439     }
 440 }
 441
 442 void CService::Init()
 443 {
 444     port = 0;
 445 }
 446
 447 CService::CService()
 448 {
 449     Init();
 450 }
 451
 452 CService::CService(const CNetAddr& cip, unsigned short portIn) : CNetAddr(cip), port(portIn)
 453 {
 454 }
 455
 456 CService::CService(const struct in_addr& ipv4Addr, unsigned short portIn) : CNetAddr(ipv4Addr), port(portIn)
 457 {
 458 }
 459
 460 CService::CService(const struct in6_addr& ipv6Addr, unsigned short portIn) : CNetAddr(ipv6Addr), port(portIn)
 461 {
 462 }
 463
 464 CService::CService(const struct sockaddr_in& addr) : CNetAddr(addr.sin_addr), port(ntohs(addr.sin_port))
 465 {
 466     assert(addr.sin_family == AF_INET);
 467 }
 468
 469 CService::CService(const struct sockaddr_in6 &addr) : CNetAddr(addr.sin6_addr, addr.sin6_scope_id), port(ntohs(addr.sin6_port))
 470 {
 471    assert(addr.sin6_family == AF_INET6);
 472 }
 473
 474 bool CService::SetSockAddr(const struct sockaddr *paddr)
 475 {
 476     switch (paddr->sa_family) {
 477     case AF_INET:
 478         *this = CService(*(const struct sockaddr_in*)paddr);
 479         return true;
 480     case AF_INET6:
 481         *this = CService(*(const struct sockaddr_in6*)paddr);
 482         return true;
 483     default:
 484         return false;
 485     }
 486 }
 487
 488 unsigned short CService::GetPort() const
 489 {
 490     return port;
 491 }
 492
 493 bool operator==(const CService& a, const CService& b)
 494 {
 495     return (CNetAddr)a == (CNetAddr)b && a.port == b.port;
 496 }
 497
 498 bool operator!=(const CService& a, const CService& b)
 499 {
 500     return (CNetAddr)a != (CNetAddr)b || a.port != b.port;
 501 }
 502
 503 bool operator<(const CService& a, const CService& b)
 504 {
 505     return (CNetAddr)a < (CNetAddr)b || ((CNetAddr)a == (CNetAddr)b && a.port < b.port);
 506 }
 507
 508 bool CService::GetSockAddr(struct sockaddr* paddr, socklen_t *addrlen) const
 509 {
 510     if (IsIPv4()) {
 511         if (*addrlen < (socklen_t)sizeof(struct sockaddr_in))
 512             return false;
 513         *addrlen = sizeof(struct sockaddr_in);
 514         struct sockaddr_in *paddrin = (struct sockaddr_in*)paddr;
 515         memset(paddrin, 0, *addrlen);
 516         if (!GetInAddr(&paddrin->sin_addr))
 517             return false;
 518         paddrin->sin_family = AF_INET;
 519         paddrin->sin_port = htons(port);
 520         return true;
 521     }
 522     if (IsIPv6()) {
 523         if (*addrlen < (socklen_t)sizeof(struct sockaddr_in6))
 524             return false;
 525         *addrlen = sizeof(struct sockaddr_in6);
 526         struct sockaddr_in6 *paddrin6 = (struct sockaddr_in6*)paddr;
 527         memset(paddrin6, 0, *addrlen);
 528         if (!GetIn6Addr(&paddrin6->sin6_addr))
 529             return false;
 530         paddrin6->sin6_scope_id = scopeId;
 531         paddrin6->sin6_family = AF_INET6;
 532         paddrin6->sin6_port = htons(port);
 533         return true;
 534     }
 535     return false;
 536 }
 537
 538 std::vector<unsigned char> CService::GetKey() const
 539 {
 540      std::vector<unsigned char> vKey;
 541      vKey.resize(18);
 542      memcpy(&vKey[0], ip, 16);
 543      vKey[16] = port / 0x100;
 544      vKey[17] = port & 0x0FF;
 545      return vKey;
 546 }
 547
 548 std::string CService::ToStringPort() const
 549 {
 550     return strprintf("%u", port);
 551 }
 552
 553 std::string CService::ToStringIPPort() const
 554 {
 555     if (IsIPv4() || IsTor()) {
 556         return ToStringIP() + ":" + ToStringPort();
 557     } else {
 558         return "[" + ToStringIP() + "]:" + ToStringPort();
 559     }
 560 }
 561
 562 std::string CService::ToString() const
 563 {
 564     return ToStringIPPort();
 565 }
 566
 567 void CService::SetPort(unsigned short portIn)
 568 {
 569     port = portIn;
 570 }
 571
 572 CSubNet::CSubNet():
 573     valid(false)
 574 {
 575     memset(netmask, 0, sizeof(netmask));
 576 }
 577
 578 CSubNet::CSubNet(const CNetAddr &addr, int32_t mask)
 579 {
 580     valid = true;
 581     network = addr;
 582     // Default to /32 (IPv4) or /128 (IPv6), i.e. match single address
 583     memset(netmask, 255, sizeof(netmask));
 584
 585     // IPv4 addresses start at offset 12, and first 12 bytes must match, so just offset n
 586     const int astartofs = network.IsIPv4() ? 12 : 0;
 587
 588     int32_t n = mask;
 589     if(n >= 0 && n <= (128 - astartofs*8)) // Only valid if in range of bits of address
 590     {
 591         n += astartofs*8;
 592         // Clear bits [n..127]
 593         for (; n < 128; ++n)
 594             netmask[n>>3] &= ~(1<<(7-(n&7)));
 595     } else
 596         valid = false;
 597
 598     // Normalize network according to netmask
 599     for(int x=0; x<16; ++x)
 600         network.ip[x] &= netmask[x];
 601 }
 602
 603 CSubNet::CSubNet(const CNetAddr &addr, const CNetAddr &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     for(int x=astartofs; x<16; ++x)
 614         netmask[x] = mask.ip[x];
 615
 616     // Normalize network according to netmask
 617     for(int x=0; x<16; ++x)
 618         network.ip[x] &= netmask[x];
 619 }
 620
 621 CSubNet::CSubNet(const CNetAddr &addr):
 622     valid(addr.IsValid())
 623 {
 624     memset(netmask, 255, sizeof(netmask));
 625     network = addr;
 626 }
 627
 628 bool CSubNet::Match(const CNetAddr &addr) const
 629 {
 630     if (!valid || !addr.IsValid())
 631         return false;
 632     for(int x=0; x<16; ++x)
 633         if ((addr.ip[x] & netmask[x]) != network.ip[x])
 634             return false;
 635     return true;
 636 }
 637
 638 static inline int NetmaskBits(uint8_t x)
 639 {
 640     switch(x) {
 641     case 0x00: return 0; break;
 642     case 0x80: return 1; break;
 643     case 0xc0: return 2; break;
 644     case 0xe0: return 3; break;
 645     case 0xf0: return 4; break;
 646     case 0xf8: return 5; break;
 647     case 0xfc: return 6; break;
 648     case 0xfe: return 7; break;
 649     case 0xff: return 8; break;
 650     default: return -1; break;
 651     }
 652 }
 653
 654 std::string CSubNet::ToString() const
 655 {
 656     /* Parse binary 1{n}0{N-n} to see if mask can be represented as /n */
 657     int cidr = 0;
 658     bool valid_cidr = true;
 659     int n = network.IsIPv4() ? 12 : 0;
 660     for (; n < 16 && netmask[n] == 0xff; ++n)
 661         cidr += 8;
 662     if (n < 16) {
 663         int bits = NetmaskBits(netmask[n]);
 664         if (bits < 0)
 665             valid_cidr = false;
 666         else
 667             cidr += bits;
 668         ++n;
 669     }
 670     for (; n < 16 && valid_cidr; ++n)
 671         if (netmask[n] != 0x00)
 672             valid_cidr = false;
 673
 674     /* Format output */
 675     std::string strNetmask;
 676     if (valid_cidr) {
 677         strNetmask = strprintf("%u", cidr);
 678     } else {
 679         if (network.IsIPv4())
 680             strNetmask = strprintf("%u.%u.%u.%u", netmask[12], netmask[13], netmask[14], netmask[15]);
 681         else
 682             strNetmask = strprintf("%x:%x:%x:%x:%x:%x:%x:%x",
 683                              netmask[0] << 8 | netmask[1], netmask[2] << 8 | netmask[3],
 684                              netmask[4] << 8 | netmask[5], netmask[6] << 8 | netmask[7],
 685                              netmask[8] << 8 | netmask[9], netmask[10] << 8 | netmask[11],
 686                              netmask[12] << 8 | netmask[13], netmask[14] << 8 | netmask[15]);
 687     }
 688
 689     return network.ToString() + "/" + strNetmask;
 690 }
 691
 692 bool CSubNet::IsValid() const
 693 {
 694     return valid;
 695 }
 696
 697 bool operator==(const CSubNet& a, const CSubNet& b)
 698 {
 699     return a.valid == b.valid && a.network == b.network && !memcmp(a.netmask, b.netmask, 16);
 700 }
 701
 702 bool operator!=(const CSubNet& a, const CSubNet& b)
 703 {
 704     return !(a==b);
 705 }
 706
 707 bool operator<(const CSubNet& a, const CSubNet& b)
 708 {
 709     return (a.network < b.network || (a.network == b.network && memcmp(a.netmask, b.netmask, 16) < 0));
 710 }