Package io.netty.util

Class NetUtil

java.lang.Object
io.netty.util.NetUtil
public final class NetUtil extends Object
A class that holds a number of network-related constants.

This class borrowed some of its methods from a modified fork of the Inet6Util class which was part of Apache Harmony.

  • Field Details

    • LOCALHOST4

      public static final Inet4Address LOCALHOST4
      The Inet4Address that represents the IPv4 loopback address '127.0.0.1'

    • LOCALHOST6

      public static final Inet6Address LOCALHOST6
      The Inet6Address that represents the IPv6 loopback address '::1'

    • LOCALHOST

      public static final InetAddress LOCALHOST
      The InetAddress that represents the loopback address. If IPv6 stack is available, it will refer to LOCALHOST6. Otherwise, LOCALHOST4.

    • LOOPBACK_IF

      public static final NetworkInterface LOOPBACK_IF
      The loopback NetworkInterface of the current machine

    • NETWORK_INTERFACES

      public static final Collection<NetworkInterface> NETWORK_INTERFACES
      An unmodifiable Collection of all the interfaces on this machine.

    • SOMAXCONN

      public static final int SOMAXCONN
      The SOMAXCONN value of the current machine. If failed to get the value, 200 is used as a default value for Windows and 128 for others.

    • IPV6_WORD_COUNT

      private static final int IPV6_WORD_COUNT
      This defines how many words (represented as ints) are needed to represent an IPv6 address
      See Also:

    • IPV6_MAX_CHAR_COUNT

      private static final int IPV6_MAX_CHAR_COUNT
      The maximum number of characters for an IPV6 string with no scope
      See Also:

    • IPV6_BYTE_COUNT

      private static final int IPV6_BYTE_COUNT
      Number of bytes needed to represent an IPV6 value
      See Also:

    • IPV6_MAX_CHAR_BETWEEN_SEPARATOR

      private static final int IPV6_MAX_CHAR_BETWEEN_SEPARATOR
      Maximum amount of value adding characters in between IPV6 separators
      See Also:

    • IPV6_MIN_SEPARATORS

      private static final int IPV6_MIN_SEPARATORS
      Minimum number of separators that must be present in an IPv6 string
      See Also:

    • IPV6_MAX_SEPARATORS

      private static final int IPV6_MAX_SEPARATORS
      Maximum number of separators that must be present in an IPv6 string
      See Also:

    • IPV4_MAX_CHAR_BETWEEN_SEPARATOR

      private static final int IPV4_MAX_CHAR_BETWEEN_SEPARATOR
      Maximum amount of value adding characters in between IPV4 separators
      See Also:

    • IPV4_SEPARATORS

      private static final int IPV4_SEPARATORS
      Number of separators that must be present in an IPv4 string
      See Also:

    • IPV4_PREFERRED

      private static final boolean IPV4_PREFERRED
      true if IPv4 should be used even if the system supports both IPv4 and IPv6.

    • IPV6_ADDRESSES_PREFERRED

      private static final boolean IPV6_ADDRESSES_PREFERRED
      true if an IPv6 address should be preferred when a host has both an IPv4 address and an IPv6 address.

    • logger

      private static final InternalLogger logger
      The logger being used by this class

  • Constructor Details

    • NetUtil

      private NetUtil()
      A constructor to stop this class being constructed.

  • Method Details

    • sysctlGetInt

      private static Integer sysctlGetInt(String sysctlKey) throws IOException
      This will execute sysctl with the sysctlKey which is expected to return the numeric value for for sysctlKey.
      Parameters:
      sysctlKey - The key which the return value corresponds to.
      Returns:
      The sysctl value for sysctlKey.
      Throws:
      IOException

    • isIpV4StackPreferred

      public static boolean isIpV4StackPreferred()
      Returns true if IPv4 should be used even if the system supports both IPv4 and IPv6. Setting this property to true will disable IPv6 support. The default value of this property is false.
      See Also:

    • isIpV6AddressesPreferred

      public static boolean isIpV6AddressesPreferred()
      Returns true if an IPv6 address should be preferred when a host has both an IPv4 address and an IPv6 address. The default value of this property is false.
      See Also:

    • createByteArrayFromIpAddressString

      public static byte[] createByteArrayFromIpAddressString(String ipAddressString)
      Creates an byte[] based on an ipAddressString. No error handling is performed here.

    • createInetAddressFromIpAddressString

      public static InetAddress createInetAddressFromIpAddressString(String ipAddressString)
      Creates an InetAddress based on an ipAddressString or might return null if it can't be parsed. No error handling is performed here.

    • decimalDigit

      private static int decimalDigit(String str, int pos)

    • ipv4WordToByte

      private static byte ipv4WordToByte(String ip, int from, int toExclusive)

    • validIpV4ToBytes

      static byte[] validIpV4ToBytes(String ip)

    • ipv4AddressToInt

      public static int ipv4AddressToInt(Inet4Address ipAddress)
      Convert Inet4Address into int

    • intToIpAddress

      public static String intToIpAddress(int i)
      Converts a 32-bit integer into an IPv4 address.

    • bytesToIpAddress

      public static String bytesToIpAddress(byte[] bytes)
      Converts 4-byte or 16-byte data into an IPv4 or IPv6 string respectively.
      Throws:
      IllegalArgumentException - if length is not 4 nor 16

    • bytesToIpAddress

      public static String bytesToIpAddress(byte[] bytes, int offset, int length)
      Converts 4-byte or 16-byte data into an IPv4 or IPv6 string respectively.
      Throws:
      IllegalArgumentException - if length is not 4 nor 16

    • isValidIpV6Address

      public static boolean isValidIpV6Address(String ip)

    • isValidIpV6Address

      public static boolean isValidIpV6Address(CharSequence ip)

    • isValidIpV4Word

      private static boolean isValidIpV4Word(CharSequence word, int from, int toExclusive)

    • isValidHexChar

      private static boolean isValidHexChar(char c)

    • isValidNumericChar

      private static boolean isValidNumericChar(char c)

    • isValidIPv4MappedChar

      private static boolean isValidIPv4MappedChar(char c)

    • isValidIPv4MappedSeparators

      private static boolean isValidIPv4MappedSeparators(byte b0, byte b1, boolean mustBeZero)

    • isValidIPv4Mapped

      private static boolean isValidIPv4Mapped(byte[] bytes, int currentIndex, int compressBegin, int compressLength)

    • isValidIpV4Address

      public static boolean isValidIpV4Address(CharSequence ip)
      Takes a CharSequence and parses it to see if it is a valid IPV4 address.
      Returns:
      true, if the string represents an IPV4 address in dotted notation, false otherwise

    • isValidIpV4Address

      public static boolean isValidIpV4Address(String ip)
      Takes a String and parses it to see if it is a valid IPV4 address.
      Returns:
      true, if the string represents an IPV4 address in dotted notation, false otherwise

    • isValidIpV4Address

      private static boolean isValidIpV4Address(CharSequence ip, int from, int toExcluded)

    • isValidIpV4Address

      private static boolean isValidIpV4Address(String ip, int from, int toExcluded)

    • isValidIpV4Address

      private static boolean isValidIpV4Address(AsciiString ip, int from, int toExcluded)

    • isValidIpV4Address0

      private static boolean isValidIpV4Address0(CharSequence ip, int from, int toExcluded)

    • getByName

      public static Inet6Address getByName(CharSequence ip)
      Returns the Inet6Address representation of a CharSequence IP address.

      This method will treat all IPv4 type addresses as "IPv4 mapped" (see getByName(CharSequence, boolean))

      Parameters:
      ip - CharSequence IP address to be converted to a Inet6Address
      Returns:
      Inet6Address representation of the ip or null if not a valid IP address.

    • getByName

      public static Inet6Address getByName(CharSequence ip, boolean ipv4Mapped)
      Returns the Inet6Address representation of a CharSequence IP address.

      The ipv4Mapped parameter specifies how IPv4 addresses should be treated. "IPv4 mapped" format as defined in rfc 4291 section 2 is supported.

      Parameters:
      ip - CharSequence IP address to be converted to a Inet6Address
      ipv4Mapped -
      • true To allow IPv4 mapped inputs to be translated into Inet6Address
      • false Consider IPv4 mapped addresses as invalid.
      Returns:
      Inet6Address representation of the ip or null if not a valid IP address.

    • getIPv6ByName

      static byte[] getIPv6ByName(CharSequence ip, boolean ipv4Mapped)
      Returns the byte array representation of a CharSequence IP address.

      The ipv4Mapped parameter specifies how IPv4 addresses should be treated. "IPv4 mapped" format as defined in rfc 4291 section 2 is supported.

      Parameters:
      ip - CharSequence IP address to be converted to a Inet6Address
      ipv4Mapped -
      • true To allow IPv4 mapped inputs to be translated into Inet6Address
      • false Consider IPv4 mapped addresses as invalid.
      Returns:
      byte array representation of the ip or null if not a valid IP address.

    • toSocketAddressString

      public static String toSocketAddressString(InetSocketAddress addr)
      Returns the String representation of an InetSocketAddress.

      The output does not include Scope ID.

      Parameters:
      addr - InetSocketAddress to be converted to an address string
      Returns:
      String containing the text-formatted IP address

    • toSocketAddressString

      public static String toSocketAddressString(String host, int port)
      Returns the String representation of a host port combo.

    • newSocketAddressStringBuilder

      private static StringBuilder newSocketAddressStringBuilder(String host, String port, boolean ipv4)

    • toAddressString

      public static String toAddressString(InetAddress ip)
      Returns the String representation of an InetAddress.

      The output does not include Scope ID.

      Parameters:
      ip - InetAddress to be converted to an address string
      Returns:
      String containing the text-formatted IP address

    • toAddressString

      public static String toAddressString(InetAddress ip, boolean ipv4Mapped)
      Returns the String representation of an InetAddress.

      The output does not include Scope ID.

      Parameters:
      ip - InetAddress to be converted to an address string
      ipv4Mapped -
      • true to stray from strict rfc 5952 and support the "IPv4 mapped" format defined in rfc 4291 section 2 while still following the updated guidelines in rfc 5952 section 4
      • false to strictly follow rfc 5952
      Returns:
      String containing the text-formatted IP address

    • toAddressString

      private static String toAddressString(byte[] bytes, int offset, boolean ipv4Mapped)

    • getHostname

      public static String getHostname(InetSocketAddress addr)
      Returns InetSocketAddress.getHostString() if Java >= 7, or InetSocketAddress.getHostName() otherwise.
      Parameters:
      addr - The address
      Returns:
      the host string

    • inRangeEndExclusive

      private static boolean inRangeEndExclusive(int value, int start, int end)
      Does a range check on value if is within start (inclusive) and end (exclusive).
      Parameters:
      value - The value to checked if is within start (inclusive) and end (exclusive)
      start - The start of the range (inclusive)
      end - The end of the range (exclusive)
      Returns:
      • true if value if is within start (inclusive) and end (exclusive)
      • false otherwise