X-Git-Url: http://plrg.eecs.uci.edu/git/?p=folly.git;a=blobdiff_plain;f=folly%2FIPAddressV6.cpp;h=cdd82acc46a6fd0826c41917ad8e8fa87c11ee77;hp=45e9e3a1ceea957668db595fbc6fdd17450ef3a6;hb=f6ed4a26c0f3e6ba12788206e54add9db18e4dd6;hpb=7ffe7766f032914384aa6e0b9598bab7d9a90602

diff --git a/folly/IPAddressV6.cpp b/folly/IPAddressV6.cpp
index 45e9e3a1..cdd82acc 100644
--- a/folly/IPAddressV6.cpp
+++ b/folly/IPAddressV6.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 2014 Facebook, Inc.
+ * Copyright 2017 Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,6 +23,20 @@
 #include <folly/IPAddress.h>
 #include <folly/IPAddressV4.h>
 #include <folly/MacAddress.h>
+#include <folly/detail/IPAddressSource.h>
+
+#if !_WIN32
+#include <net/if.h>
+#else
+// Because of the massive pain that is libnl, this can't go into the socket
+// portability header as you can't include <linux/if.h> and <net/if.h> in
+// the same translation unit without getting errors -_-...
+#include <iphlpapi.h> // @manual
+#include <ntddndis.h> // @manual
+
+// Alias the max size of an interface name to what posix expects.
+#define IFNAMSIZ IF_NAMESIZE
+#endif
 
 using std::ostream;
 using std::string;
@@ -48,18 +62,30 @@ void toAppend(IPAddressV6 addr, fbstring* result) {
   result->append(addr.str());
 }
 
-// public default constructor
-IPAddressV6::IPAddressV6() {
+bool IPAddressV6::validate(StringPiece ip) noexcept {
+  return tryFromString(ip).hasValue();
 }
 
+// public default constructor
+IPAddressV6::IPAddressV6() {}
+
 // public string constructor
 IPAddressV6::IPAddressV6(StringPiece addr) {
-  auto ip = addr.str();
+  auto maybeIp = tryFromString(addr);
+  if (maybeIp.hasError()) {
+    throw IPAddressFormatException(
+        to<std::string>("Invalid IPv6 address '", addr, "'"));
+  }
+  *this = std::move(maybeIp.value());
+}
+
+Expected<IPAddressV6, IPAddressFormatError> IPAddressV6::tryFromString(
+    StringPiece str) noexcept {
+  auto ip = str.str();
 
   // Allow addresses surrounded in brackets
   if (ip.size() < 2) {
-    throw IPAddressFormatException("Invalid IPv6 address '", ip,
-                                   "': address too short");
+    return makeUnexpected(IPAddressFormatError::INVALID_IP);
   }
   if (ip.front() == '[' && ip.back() == ']') {
     ip = ip.substr(1, ip.size() - 2);
@@ -71,46 +97,36 @@ IPAddressV6::IPAddressV6(StringPiece addr) {
   hints.ai_family = AF_INET6;
   hints.ai_socktype = SOCK_STREAM;
   hints.ai_flags = AI_NUMERICHOST;
-  if (!getaddrinfo(ip.c_str(), nullptr, &hints, &result)) {
-    struct sockaddr_in6* ipAddr = (struct sockaddr_in6*)result->ai_addr;
-    addr_.in6Addr_ = ipAddr->sin6_addr;
-    scope_ = ipAddr->sin6_scope_id;
-    freeaddrinfo(result);
-  } else {
-    throw IPAddressFormatException("Invalid IPv6 address '", ip, "'");
+  if (::getaddrinfo(ip.c_str(), nullptr, &hints, &result) == 0) {
+    SCOPE_EXIT {
+      ::freeaddrinfo(result);
+    };
+    const struct sockaddr_in6* sa =
+        reinterpret_cast<struct sockaddr_in6*>(result->ai_addr);
+    return IPAddressV6(*sa);
   }
+  return makeUnexpected(IPAddressFormatError::INVALID_IP);
 }
 
 // in6_addr constructor
-IPAddressV6::IPAddressV6(const in6_addr& src)
-  : addr_(src)
-{
-}
+IPAddressV6::IPAddressV6(const in6_addr& src) noexcept : addr_(src) {}
 
 // sockaddr_in6 constructor
-IPAddressV6::IPAddressV6(const sockaddr_in6& src)
-  : addr_(src.sin6_addr)
-  , scope_(src.sin6_scope_id)
-{
-}
+IPAddressV6::IPAddressV6(const sockaddr_in6& src) noexcept
+    : addr_(src.sin6_addr), scope_(uint16_t(src.sin6_scope_id)) {}
 
 // ByteArray16 constructor
-IPAddressV6::IPAddressV6(const ByteArray16& src)
-  : addr_(src)
-{
-}
+IPAddressV6::IPAddressV6(const ByteArray16& src) noexcept : addr_(src) {}
 
 // link-local constructor
-IPAddressV6::IPAddressV6(LinkLocalTag, MacAddress mac)
-  : addr_(mac) {
-}
+IPAddressV6::IPAddressV6(LinkLocalTag, MacAddress mac) : addr_(mac) {}
 
 IPAddressV6::AddressStorage::AddressStorage(MacAddress mac) {
   // The link-local address uses modified EUI-64 format,
   // See RFC 4291 sections 2.5.1, 2.5.6, and Appendix A
   const auto* macBytes = mac.bytes();
   memcpy(&bytes_.front(), "\xfe\x80\x00\x00\x00\x00\x00\x00", 8);
-  bytes_[8] = macBytes[0] ^ 0x02;
+  bytes_[8] = uint8_t(macBytes[0] ^ 0x02);
   bytes_[9] = macBytes[1];
   bytes_[10] = macBytes[2];
   bytes_[11] = 0xff;
@@ -120,13 +136,91 @@ IPAddressV6::AddressStorage::AddressStorage(MacAddress mac) {
   bytes_[15] = macBytes[5];
 }
 
-void IPAddressV6::setFromBinary(ByteRange bytes) {
+Optional<MacAddress> IPAddressV6::getMacAddressFromLinkLocal() const {
+  // Returned MacAddress must be constructed from a link-local IPv6 address.
+  if (!isLinkLocal()) {
+    return folly::none;
+  }
+  return getMacAddressFromEUI64();
+}
+
+Optional<MacAddress> IPAddressV6::getMacAddressFromEUI64() const {
+  if (!(addr_.bytes_[11] == 0xff && addr_.bytes_[12] == 0xfe)) {
+    return folly::none;
+  }
+  // The auto configured address uses modified EUI-64 format,
+  // See RFC 4291 sections 2.5.1, 2.5.6, and Appendix A
+  std::array<uint8_t, MacAddress::SIZE> bytes;
+  // Step 1: first 8 bytes are network prefix, and can be stripped
+  // Step 2: invert the universal/local (U/L) flag (bit 7)
+  bytes[0] = addr_.bytes_[8] ^ 0x02;
+  // Step 3: copy these bytes as they are
+  bytes[1] = addr_.bytes_[9];
+  bytes[2] = addr_.bytes_[10];
+  // Step 4: strip bytes (0xfffe), which are bytes_[11] and bytes_[12]
+  // Step 5: copy the rest.
+  bytes[3] = addr_.bytes_[13];
+  bytes[4] = addr_.bytes_[14];
+  bytes[5] = addr_.bytes_[15];
+  return Optional<MacAddress>(MacAddress::fromBinary(range(bytes)));
+}
+
+IPAddressV6 IPAddressV6::fromBinary(ByteRange bytes) {
+  auto maybeIp = tryFromBinary(bytes);
+  if (maybeIp.hasError()) {
+    throw IPAddressFormatException(to<std::string>(
+        "Invalid IPv6 binary data: length must be 16 bytes, got ",
+        bytes.size()));
+  }
+  return maybeIp.value();
+}
+
+Expected<IPAddressV6, IPAddressFormatError> IPAddressV6::tryFromBinary(
+    ByteRange bytes) noexcept {
+  IPAddressV6 addr;
+  auto setResult = addr.trySetFromBinary(bytes);
+  if (setResult.hasError()) {
+    return makeUnexpected(std::move(setResult.error()));
+  }
+  return addr;
+}
+
+Expected<Unit, IPAddressFormatError> IPAddressV6::trySetFromBinary(
+    ByteRange bytes) noexcept {
   if (bytes.size() != 16) {
-    throw IPAddressFormatException("Invalid IPv6 binary data: length must "
-                                   "be 16 bytes, got ", bytes.size());
+    return makeUnexpected(IPAddressFormatError::INVALID_IP);
   }
   memcpy(&addr_.in6Addr_.s6_addr, bytes.data(), sizeof(in6_addr));
   scope_ = 0;
+  return unit;
+}
+
+// static
+IPAddressV6 IPAddressV6::fromInverseArpaName(const std::string& arpaname) {
+  auto piece = StringPiece(arpaname);
+  if (!piece.removeSuffix(".ip6.arpa")) {
+    throw IPAddressFormatException(sformat(
+        "Invalid input. Should end with 'ip6.arpa'. Got '{}'", arpaname));
+  }
+  std::vector<StringPiece> pieces;
+  split(".", piece, pieces);
+  if (pieces.size() != 32) {
+    throw IPAddressFormatException(sformat("Invalid input. Got '{}'", piece));
+  }
+  std::array<char, IPAddressV6::kToFullyQualifiedSize> ip;
+  size_t pos = 0;
+  int count = 0;
+  for (size_t i = 1; i <= pieces.size(); i++) {
+    ip[pos] = pieces[pieces.size() - i][0];
+    pos++;
+    count++;
+    // add ':' every 4 chars
+    if (count == 4 && pos < ip.size()) {
+      ip[pos++] = ':';
+      count = 0;
+    }
+  }
+  return IPAddressV6(folly::range(ip));
 }
 
 // public
@@ -140,14 +234,13 @@ IPAddressV4 IPAddressV6::createIPv4() const {
 
 // convert two uint8_t bytes into a uint16_t as hibyte.lobyte
 static inline uint16_t unpack(uint8_t lobyte, uint8_t hibyte) {
-  return ((uint16_t)hibyte << 8) | (uint16_t)lobyte;
+  return uint16_t((uint16_t(hibyte) << 8) | lobyte);
 }
 
 // given a src string, unpack count*2 bytes into dest
 // dest must have as much storage as count
-static inline void unpackInto(const unsigned char* src,
-                              uint16_t* dest,
-                              size_t count) {
+static inline void
+unpackInto(const unsigned char* src, uint16_t* dest, size_t count) {
   for (size_t i = 0, hi = 1, lo = 0; i < count; i++) {
     dest[i] = unpack(src[hi], src[lo]);
     hi += 2;
@@ -158,11 +251,11 @@ static inline void unpackInto(const unsigned char* src,
 // public
 IPAddressV4 IPAddressV6::getIPv4For6To4() const {
   if (!is6To4()) {
-    throw IPAddressV6::TypeError(format(
-            "Invalid IP '{}': not a 6to4 address", str()).str());
+    throw IPAddressV6::TypeError(
+        sformat("Invalid IP '{}': not a 6to4 address", str()));
   }
   // convert 16x8 bytes into first 4x16 bytes
-  uint16_t ints[4] = {0,0,0,0};
+  uint16_t ints[4] = {0, 0, 0, 0};
   unpackInto(bytes(), ints, 4);
   // repack into 4x8
   union {
@@ -198,7 +291,7 @@ bool IPAddressV6::isIPv4Mapped() const {
 // public
 IPAddressV6::Type IPAddressV6::type() const {
   // convert 16x8 bytes into first 2x16 bytes
-  uint16_t ints[2] = {0,0};
+  uint16_t ints[2] = {0, 0};
   unpackInto(bytes(), ints, 2);
 
   if ((((uint32_t)ints[0] << 16) | ints[1]) == IPAddressV6::PREFIX_TEREDO) {
@@ -214,8 +307,7 @@ IPAddressV6::Type IPAddressV6::type() const {
 
 // public
 string IPAddressV6::toJson() const {
-  return format(
-      "{{family:'AF_INET6', addr:'{}', hash:{}}}", str(), hash()).str();
+  return sformat("{{family:'AF_INET6', addr:'{}', hash:{}}}", str(), hash());
 }
 
 // public
@@ -238,18 +330,18 @@ bool IPAddressV6::inSubnet(StringPiece cidrNetwork) const {
   auto subnetInfo = IPAddress::createNetwork(cidrNetwork);
   auto addr = subnetInfo.first;
   if (!addr.isV6()) {
-    throw IPAddressFormatException("Address '", addr.toJson(), "' ",
-                                   "is not a V6 address");
+    throw IPAddressFormatException(
+        sformat("Address '{}' is not a V6 address", addr.toJson()));
   }
   return inSubnetWithMask(addr.asV6(), fetchMask(subnetInfo.second));
 }
 
 // public
-bool IPAddressV6::inSubnetWithMask(const IPAddressV6& subnet,
-                                   const ByteArray16& cidrMask) const {
-  const ByteArray16 mask = detail::Bytes::mask(toByteArray(), cidrMask);
-  const ByteArray16 subMask = detail::Bytes::mask(subnet.toByteArray(),
-                                                  cidrMask);
+bool IPAddressV6::inSubnetWithMask(
+    const IPAddressV6& subnet,
+    const ByteArray16& cidrMask) const {
+  const auto mask = detail::Bytes::mask(toByteArray(), cidrMask);
+  const auto subMask = detail::Bytes::mask(subnet.toByteArray(), cidrMask);
   return (mask == subMask);
 }
 
@@ -265,11 +357,11 @@ bool IPAddressV6::isLoopback() const {
 
 bool IPAddressV6::isRoutable() const {
   return
-    // 2000::/3 is the only assigned global unicast block
-    inBinarySubnet({{0x20, 0x00}}, 3) ||
-    // ffxe::/16 are global scope multicast addresses,
-    // which are eligible to be routed over the internet
-    (isMulticast() && getMulticastScope() == 0xe);
+      // 2000::/3 is the only assigned global unicast block
+      inBinarySubnet({{0x20, 0x00}}, 3) ||
+      // ffxe::/16 are global scope multicast addresses,
+      // which are eligible to be routed over the internet
+      (isMulticast() && getMulticastScope() == 0xe);
 }
 
 bool IPAddressV6::isLinkLocalBroadcast() const {
@@ -286,6 +378,7 @@ bool IPAddressV6::isPrivate() const {
   return isLoopback() || inBinarySubnet({{0xfc, 0x00}}, 7);
 }
 
+// public
 bool IPAddressV6::isLinkLocal() const {
   return inBinarySubnet({{0xfe, 0x80}}, 10);
 }
@@ -296,12 +389,12 @@ bool IPAddressV6::isMulticast() const {
 
 uint8_t IPAddressV6::getMulticastFlags() const {
   DCHECK(isMulticast());
-  return ((addr_.bytes_[1] >> 4) & 0xf);
+  return uint8_t((addr_.bytes_[1] >> 4) & 0xf);
 }
 
 uint8_t IPAddressV6::getMulticastScope() const {
   DCHECK(isMulticast());
-  return (addr_.bytes_[1] & 0xf);
+  return uint8_t(addr_.bytes_[1] & 0xf);
 }
 
 IPAddressV6 IPAddressV6::getSolicitedNodeAddress() const {
@@ -309,11 +402,24 @@ IPAddressV6 IPAddressV6::getSolicitedNodeAddress() const {
   // addresses
   DCHECK(!isMulticast());
 
-  uint8_t bytes[16] = { 0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-                        0x00, 0x00, 0x00, 0x01, 0xff, 0x00, 0x00, 0x00 };
-  bytes[13] = addr_.bytes_[13];
-  bytes[14] = addr_.bytes_[14];
-  bytes[15] = addr_.bytes_[15];
+  uint8_t bytes[16] = {
+      0xff,
+      0x02,
+      0x00,
+      0x00,
+      0x00,
+      0x00,
+      0x00,
+      0x00,
+      0x00,
+      0x00,
+      0x00,
+      0x01,
+      0xff,
+      addr_.bytes_[13],
+      addr_.bytes_[14],
+      addr_.bytes_[15],
+  };
   return IPAddressV6::fromBinary(ByteRange(bytes, 16));
 }
 
@@ -321,8 +427,8 @@ IPAddressV6 IPAddressV6::getSolicitedNodeAddress() const {
 IPAddressV6 IPAddressV6::mask(size_t numBits) const {
   static const auto bits = bitCount();
   if (numBits > bits) {
-    throw IPAddressFormatException("numBits(", numBits, ") > bitCount(",
-                                   bits, ")");
+    throw IPAddressFormatException(
+        sformat("numBits({}) > bitCount({})", numBits, bits));
   }
   ByteArray16 ba = detail::Bytes::mask(fetchMask(numBits), addr_.bytes_);
   return IPAddressV6(ba);
@@ -330,18 +436,30 @@ IPAddressV6 IPAddressV6::mask(size_t numBits) const {
 
 // public
 string IPAddressV6::str() const {
-  char buffer[INET6_ADDRSTRLEN] = {0};
-  sockaddr_in6 sock = toSockAddr();
-  if (!getnameinfo(
-        (sockaddr*)&sock, sizeof(sock),
-        buffer, INET6_ADDRSTRLEN,
-        nullptr, 0, NI_NUMERICHOST)) {
-    string ip(buffer);
-    return std::move(ip);
-  } else {
-    throw IPAddressFormatException("Invalid address with hex ",
-                                   "'", detail::Bytes::toHex(bytes(), 16), "'");
+  char buffer[INET6_ADDRSTRLEN + IFNAMSIZ + 1];
+
+  if (!inet_ntop(AF_INET6, toAddr().s6_addr, buffer, INET6_ADDRSTRLEN)) {
+    throw IPAddressFormatException(sformat(
+        "Invalid address with hex '{}' with error {}",
+        detail::Bytes::toHex(bytes(), 16),
+        strerror(errno)));
+  }
+
+  auto scopeId = getScopeId();
+  if (scopeId != 0) {
+    auto len = strlen(buffer);
+    buffer[len] = '%';
+
+    auto errsv = errno;
+    if (!if_indextoname(scopeId, buffer + len + 1)) {
+      // if we can't map the if because eg. it no longer exists,
+      // append the if index instead
+      snprintf(buffer + len + 1, IFNAMSIZ, "%u", scopeId);
+    }
+    errno = errsv;
   }
+
+  return string(buffer);
 }
 
 // public
@@ -349,12 +467,31 @@ string IPAddressV6::toFullyQualified() const {
   return detail::fastIpv6ToString(addr_.in6Addr_);
 }
 
+// public
+void IPAddressV6::toFullyQualifiedAppend(std::string& out) const {
+  detail::fastIpv6AppendToString(addr_.in6Addr_, out);
+}
+
+// public
+string IPAddressV6::toInverseArpaName() const {
+  constexpr folly::StringPiece lut = "0123456789abcdef";
+  std::array<char, 32> a;
+  int j = 0;
+  for (int i = 15; i >= 0; i--) {
+    a[j] = (lut[bytes()[i] & 0xf]);
+    a[j + 1] = (lut[bytes()[i] >> 4]);
+    j += 2;
+  }
+  return sformat("{}.ip6.arpa", join(".", a));
+}
+
 // public
 uint8_t IPAddressV6::getNthMSByte(size_t byteIndex) const {
   const auto highestIndex = byteCount() - 1;
   if (byteIndex > highestIndex) {
-    throw std::invalid_argument(to<string>("Byte index must be <= ",
-        to<string>(highestIndex), " for addresses of type :",
+    throw std::invalid_argument(sformat(
+        "Byte index must be <= {} for addresses of type: {}",
+        highestIndex,
         detail::familyNameStr(AF_INET6)));
   }
   return bytes()[byteIndex];
@@ -362,539 +499,38 @@ uint8_t IPAddressV6::getNthMSByte(size_t byteIndex) const {
 
 // protected
 const ByteArray16 IPAddressV6::fetchMask(size_t numBits) {
-  static const uint8_t bits = bitCount();
+  static const size_t bits = bitCount();
   if (numBits > bits) {
     throw IPAddressFormatException("IPv6 addresses are 128 bits.");
   }
-  // masks_ is backed by an array so is zero indexed
-  return masks_[numBits];
+  if (numBits == 0) {
+    return {{0}};
+  }
+  constexpr auto _0s = uint64_t(0);
+  constexpr auto _1s = ~_0s;
+  auto const fragment = Endian::big(_1s << ((128 - numBits) % 64));
+  auto const hi = numBits <= 64 ? fragment : _1s;
+  auto const lo = numBits <= 64 ? _0s : fragment;
+  uint64_t const parts[] = {hi, lo};
+  ByteArray16 arr;
+  std::memcpy(arr.data(), parts, sizeof(parts));
+  return arr;
+}
+
+// public static
+CIDRNetworkV6 IPAddressV6::longestCommonPrefix(
+    const CIDRNetworkV6& one,
+    const CIDRNetworkV6& two) {
+  auto prefix = detail::Bytes::longestCommonPrefix(
+      one.first.addr_.bytes_, one.second, two.first.addr_.bytes_, two.second);
+  return {IPAddressV6(prefix.first), prefix.second};
 }
 
 // protected
-bool IPAddressV6::inBinarySubnet(const std::array<uint8_t, 2> addr,
-                                 size_t numBits) const {
-  const unsigned char* subbytes = mask(numBits).bytes();
-  return (std::memcmp(addr.data(), subbytes, 2) == 0);
-}
-
-// static private
-const std::array<ByteArray16, 129> IPAddressV6::masks_ = {{
-/* /0   */ {{ 0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /1   */ {{ 0x80,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /2   */ {{ 0xc0,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /3   */ {{ 0xe0,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /4   */ {{ 0xf0,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /5   */ {{ 0xf8,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /6   */ {{ 0xfc,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /7   */ {{ 0xfe,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /8   */ {{ 0xff,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /9   */ {{ 0xff,0x80,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /10  */ {{ 0xff,0xc0,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /11  */ {{ 0xff,0xe0,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /12  */ {{ 0xff,0xf0,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /13  */ {{ 0xff,0xf8,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /14  */ {{ 0xff,0xfc,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /15  */ {{ 0xff,0xfe,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /16  */ {{ 0xff,0xff,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /17  */ {{ 0xff,0xff,0x80,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /18  */ {{ 0xff,0xff,0xc0,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /19  */ {{ 0xff,0xff,0xe0,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /20  */ {{ 0xff,0xff,0xf0,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /21  */ {{ 0xff,0xff,0xf8,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /22  */ {{ 0xff,0xff,0xfc,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /23  */ {{ 0xff,0xff,0xfe,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /24  */ {{ 0xff,0xff,0xff,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /25  */ {{ 0xff,0xff,0xff,0x80,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /26  */ {{ 0xff,0xff,0xff,0xc0,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /27  */ {{ 0xff,0xff,0xff,0xe0,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /28  */ {{ 0xff,0xff,0xff,0xf0,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /29  */ {{ 0xff,0xff,0xff,0xf8,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /30  */ {{ 0xff,0xff,0xff,0xfc,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /31  */ {{ 0xff,0xff,0xff,0xfe,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /32  */ {{ 0xff,0xff,0xff,0xff,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /33  */ {{ 0xff,0xff,0xff,0xff,
-             0x80,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /34  */ {{ 0xff,0xff,0xff,0xff,
-             0xc0,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /35  */ {{ 0xff,0xff,0xff,0xff,
-             0xe0,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /36  */ {{ 0xff,0xff,0xff,0xff,
-             0xf0,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /37  */ {{ 0xff,0xff,0xff,0xff,
-             0xf8,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /38  */ {{ 0xff,0xff,0xff,0xff,
-             0xfc,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /39  */ {{ 0xff,0xff,0xff,0xff,
-             0xfe,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /40  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /41  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0x80,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /42  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xc0,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /43  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xe0,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /44  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xf0,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /45  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xf8,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /46  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xfc,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /47  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xfe,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /48  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0x00,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /49  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0x80,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /50  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xc0,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /51  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xe0,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /52  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xf0,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /53  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xf8,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /54  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xfc,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /55  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xfe,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /56  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0x00,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /57  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0x80,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /58  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xc0,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /59  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xe0,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /60  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xf0,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /61  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xf8,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /62  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xfc,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /63  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xfe,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /64  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0x00,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /65  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0x80,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /66  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xc0,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /67  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xe0,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /68  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xf0,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /69  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xf8,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /70  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xfc,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /71  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xfe,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /72  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0x00,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /73  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0x80,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /74  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xc0,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /75  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xe0,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /76  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xf0,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /77  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xf8,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /78  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xfc,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /79  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xfe,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /80  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0x00,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /81  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0x80,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /82  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xc0,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /83  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xe0,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /84  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xf0,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /85  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xf8,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /86  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xfc,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /87  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xfe,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /88  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0x00,
-             0x00,0x00,0x00,0x00 }},
-/* /89  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0x80,
-             0x00,0x00,0x00,0x00 }},
-/* /90  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xc0,
-             0x00,0x00,0x00,0x00 }},
-/* /91  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xe0,
-             0x00,0x00,0x00,0x00 }},
-/* /92  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xf0,
-             0x00,0x00,0x00,0x00 }},
-/* /93  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xf8,
-             0x00,0x00,0x00,0x00 }},
-/* /94  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xfc,
-             0x00,0x00,0x00,0x00 }},
-/* /95  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xfe,
-             0x00,0x00,0x00,0x00 }},
-/* /96  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0x00,0x00,0x00,0x00 }},
-/* /97  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0x80,0x00,0x00,0x00 }},
-/* /98  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xc0,0x00,0x00,0x00 }},
-/* /99  */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xe0,0x00,0x00,0x00 }},
-/* /100 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xf0,0x00,0x00,0x00 }},
-/* /101 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xf8,0x00,0x00,0x00 }},
-/* /102 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xfc,0x00,0x00,0x00 }},
-/* /103 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xfe,0x00,0x00,0x00 }},
-/* /104 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0x00,0x00,0x00 }},
-/* /105 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0x80,0x00,0x00 }},
-/* /106 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xc0,0x00,0x00 }},
-/* /107 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xe0,0x00,0x00 }},
-/* /108 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xf0,0x00,0x00 }},
-/* /109 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xf8,0x00,0x00 }},
-/* /110 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xfc,0x00,0x00 }},
-/* /111 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xfe,0x00,0x00 }},
-/* /112 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0x00,0x00 }},
-/* /113 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0x80,0x00 }},
-/* /114 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xc0,0x00 }},
-/* /115 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xe0,0x00 }},
-/* /116 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xf0,0x00 }},
-/* /117 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xf8,0x00 }},
-/* /118 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xfc,0x00 }},
-/* /119 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xfe,0x00 }},
-/* /120 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0x00 }},
-/* /121 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0x80 }},
-/* /122 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xc0 }},
-/* /123 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xe0 }},
-/* /124 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xf0 }},
-/* /125 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xf8 }},
-/* /126 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xfc }},
-/* /127 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xfe }},
-/* /128 */ {{ 0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff,
-             0xff,0xff,0xff,0xff }},
-}};
-
-} // folly
+bool IPAddressV6::inBinarySubnet(
+    const std::array<uint8_t, 2> addr,
+    size_t numBits) const {
+  auto masked = mask(numBits);
+  return (std::memcmp(addr.data(), masked.bytes(), 2) == 0);
+}
+} // namespace folly