Fix TLRefCount::useGlobal to work with TSAN

[folly.git] / folly / IPAddressV6.cpp

diff --git a/folly/IPAddressV6.cpp b/folly/IPAddressV6.cpp
index 328d067477e334065e24bb262913faa5b270d140..5607a4bfcb37e61eef7d7f7b2e177a9594a4426a 100644 (file)
--- a/folly/IPAddressV6.cpp
+++ b/folly/IPAddressV6.cpp
@@ -126,7 +126,7 @@ IPAddressV6::AddressStorage::AddressStorage(MacAddress mac) {
   // 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;
@@ -136,6 +136,32 @@ IPAddressV6::AddressStorage::AddressStorage(MacAddress mac) {
   bytes_[15] = macBytes[5];
 }
 
+Optional<MacAddress> IPAddressV6::getMacAddressFromLinkLocal() const {
+  // Returned MacAddress must be constructed from a link-local IPv6 address.
+  if (!(addr_.bytes_[0] == 0xfe && addr_.bytes_[1] == 0x80 &&
+        addr_.bytes_[2] == 0x00 && addr_.bytes_[3] == 0x00 &&
+        addr_.bytes_[4] == 0x00 && addr_.bytes_[5] == 0x00 &&
+        addr_.bytes_[6] == 0x00 && addr_.bytes_[7] == 0x00 &&
+        addr_.bytes_[11] == 0xff && addr_.bytes_[12] == 0xfe)) {
+    return folly::none;
+  }
+  // The link-local 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 fe:80:00:00:00:00:00:00, and can be stripped
+  // Step 2: invert the universal/local (U/L) flag (bit 7)
+  bytes[0] = addr_.bytes_[8] ^ 0x02;
+  // Step 3: copy thhese bytes are 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)));
+}
+
 void IPAddressV6::setFromBinary(ByteRange bytes) {
   if (bytes.size() != 16) {
     throw IPAddressFormatException(to<std::string>(
@@ -158,7 +184,7 @@ 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
@@ -315,12 +341,12 @@ 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 {