Involved Source Files Package netip defines an IP address type that's a small value type.
Building on that [Addr] type, the package also defines [AddrPort] (an
IP address and a port) and [Prefix] (an IP address and a bit length
prefix).
Compared to the [net.IP] type, [Addr] type takes less memory, is immutable,
and is comparable (supports == and being a map key).uint128.go
Package-Level Type Names (total 3)
/* sort by: | */
Addr represents an IPv4 or IPv6 address (with or without a scoped
addressing zone), similar to [net.IP] or [net.IPAddr].
Unlike [net.IP] or [net.IPAddr], Addr is a comparable value
type (it supports == and can be a map key) and is immutable.
The zero Addr is not a valid IP address.
Addr{} is distinct from both 0.0.0.0 and ::. AppendTo appends a text encoding of ip,
as generated by [Addr.MarshalText],
to b and returns the extended buffer. As16 returns the IP address in its 16-byte representation.
IPv4 addresses are returned as IPv4-mapped IPv6 addresses.
IPv6 addresses with zones are returned without their zone (use the
[Addr.Zone] method to get it).
The ip zero value returns all zeroes. As4 returns an IPv4 or IPv4-in-IPv6 address in its 4-byte representation.
If ip is the zero [Addr] or an IPv6 address, As4 panics.
Note that 0.0.0.0 is not the zero Addr. AsSlice returns an IPv4 or IPv6 address in its respective 4-byte or 16-byte representation. BitLen returns the number of bits in the IP address:
128 for IPv6, 32 for IPv4, and 0 for the zero [Addr].
Note that IPv4-mapped IPv6 addresses are considered IPv6 addresses
and therefore have bit length 128. Compare returns an integer comparing two IPs.
The result will be 0 if ip == ip2, -1 if ip < ip2, and +1 if ip > ip2.
The definition of "less than" is the same as the [Addr.Less] method. Is4 reports whether ip is an IPv4 address.
It returns false for IPv4-mapped IPv6 addresses. See [Addr.Unmap]. Is4In6 reports whether ip is an IPv4-mapped IPv6 address. Is6 reports whether ip is an IPv6 address, including IPv4-mapped
IPv6 addresses. IsGlobalUnicast reports whether ip is a global unicast address.
It returns true for IPv6 addresses which fall outside of the current
IANA-allocated 2000::/3 global unicast space, with the exception of the
link-local address space. It also returns true even if ip is in the IPv4
private address space or IPv6 unique local address space.
It returns false for the zero [Addr].
For reference, see RFC 1122, RFC 4291, and RFC 4632. IsInterfaceLocalMulticast reports whether ip is an IPv6 interface-local
multicast address. IsLinkLocalMulticast reports whether ip is a link-local multicast address. IsLinkLocalUnicast reports whether ip is a link-local unicast address. IsLoopback reports whether ip is a loopback address. IsMulticast reports whether ip is a multicast address. IsPrivate reports whether ip is a private address, according to RFC 1918
(IPv4 addresses) and RFC 4193 (IPv6 addresses). That is, it reports whether
ip is in 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16, or fc00::/7. This is the
same as [net.IP.IsPrivate]. IsUnspecified reports whether ip is an unspecified address, either the IPv4
address "0.0.0.0" or the IPv6 address "::".
Note that the zero [Addr] is not an unspecified address. IsValid reports whether the [Addr] is an initialized address (not the zero Addr).
Note that "0.0.0.0" and "::" are both valid values. Less reports whether ip sorts before ip2.
IP addresses sort first by length, then their address.
IPv6 addresses with zones sort just after the same address without a zone. MarshalBinary implements the [encoding.BinaryMarshaler] interface.
It returns a zero-length slice for the zero [Addr],
the 4-byte form for an IPv4 address,
and the 16-byte form with zone appended for an IPv6 address. MarshalText implements the [encoding.TextMarshaler] interface,
The encoding is the same as returned by [Addr.String], with one exception:
If ip is the zero [Addr], the encoding is the empty string. Next returns the address following ip.
If there is none, it returns the zero [Addr]. Prefix keeps only the top b bits of IP, producing a Prefix
of the specified length.
If ip is a zero [Addr], Prefix always returns a zero Prefix and a nil error.
Otherwise, if bits is less than zero or greater than ip.BitLen(),
Prefix returns an error. Prev returns the IP before ip.
If there is none, it returns the IP zero value. String returns the string form of the IP address ip.
It returns one of 5 forms:
- "invalid IP", if ip is the zero [Addr]
- IPv4 dotted decimal ("192.0.2.1")
- IPv6 ("2001:db8::1")
- "::ffff:1.2.3.4" (if [Addr.Is4In6])
- IPv6 with zone ("fe80:db8::1%eth0")
Note that unlike package net's IP.String method,
IPv4-mapped IPv6 addresses format with a "::ffff:"
prefix before the dotted quad. StringExpanded is like [Addr.String] but IPv6 addresses are expanded with leading
zeroes and no "::" compression. For example, "2001:db8::1" becomes
"2001:0db8:0000:0000:0000:0000:0000:0001". Unmap returns ip with any IPv4-mapped IPv6 address prefix removed.
That is, if ip is an IPv6 address wrapping an IPv4 address, it
returns the wrapped IPv4 address. Otherwise it returns ip unmodified. UnmarshalBinary implements the [encoding.BinaryUnmarshaler] interface.
It expects data in the form generated by MarshalBinary. UnmarshalText implements the encoding.TextUnmarshaler interface.
The IP address is expected in a form accepted by [ParseAddr].
If text is empty, UnmarshalText sets *ip to the zero [Addr] and
returns no error. WithZone returns an IP that's the same as ip but with the provided
zone. If zone is empty, the zone is removed. If ip is an IPv4
address, WithZone is a no-op and returns ip unchanged. Zone returns ip's IPv6 scoped addressing zone, if any.
Addr : database/sql/driver.Validator
Addr : encoding.BinaryMarshaler
*Addr : encoding.BinaryUnmarshaler
Addr : encoding.TextMarshaler
*Addr : encoding.TextUnmarshaler
Addr : expvar.Var
Addr : fmt.Stringer
func AddrFrom16(addr [16]byte) Addr
func AddrFrom4(addr [4]byte) Addr
func AddrFromSlice(slice []byte) (ip Addr, ok bool)
func IPv4Unspecified() Addr
func IPv6LinkLocalAllNodes() Addr
func IPv6LinkLocalAllRouters() Addr
func IPv6Loopback() Addr
func IPv6Unspecified() Addr
func MustParseAddr(s string) Addr
func ParseAddr(s string) (Addr, error)
func Addr.Next() Addr
func Addr.Prev() Addr
func Addr.Unmap() Addr
func Addr.WithZone(zone string) Addr
func AddrPort.Addr() Addr
func Prefix.Addr() Addr
func net.(*Resolver).LookupNetIP(ctx context.Context, network, host string) ([]Addr, error)
func AddrPortFrom(ip Addr, port uint16) AddrPort
func PrefixFrom(ip Addr, bits int) Prefix
func Addr.Compare(ip2 Addr) int
func Addr.Less(ip2 Addr) bool
func Prefix.Contains(ip Addr) bool
Prefix is an IP address prefix (CIDR) representing an IP network.
The first [Prefix.Bits]() of [Addr]() are specified. The remaining bits match any address.
The range of Bits() is [0,32] for IPv4 or [0,128] for IPv6. Addr returns p's IP address. AppendTo appends a text encoding of p,
as generated by [Prefix.MarshalText],
to b and returns the extended buffer. Bits returns p's prefix length.
It reports -1 if invalid. Contains reports whether the network p includes ip.
An IPv4 address will not match an IPv6 prefix.
An IPv4-mapped IPv6 address will not match an IPv4 prefix.
A zero-value IP will not match any prefix.
If ip has an IPv6 zone, Contains returns false,
because Prefixes strip zones. IsSingleIP reports whether p contains exactly one IP. IsValid reports whether p.Bits() has a valid range for p.Addr().
If p.Addr() is the zero [Addr], IsValid returns false.
Note that if p is the zero [Prefix], then p.IsValid() == false. MarshalBinary implements the [encoding.BinaryMarshaler] interface.
It returns [Addr.MarshalBinary] with an additional byte appended
containing the prefix bits. MarshalText implements the [encoding.TextMarshaler] interface,
The encoding is the same as returned by [Prefix.String], with one exception:
If p is the zero value, the encoding is the empty string. Masked returns p in its canonical form, with all but the high
p.Bits() bits of p.Addr() masked off.
If p is zero or otherwise invalid, Masked returns the zero [Prefix]. Overlaps reports whether p and o contain any IP addresses in common.
If p and o are of different address families or either have a zero
IP, it reports false. Like the Contains method, a prefix with an
IPv4-mapped IPv6 address is still treated as an IPv6 mask. String returns the CIDR notation of p: "<ip>/<bits>". UnmarshalBinary implements the [encoding.BinaryUnmarshaler] interface.
It expects data in the form generated by [Prefix.MarshalBinary]. UnmarshalText implements the encoding.TextUnmarshaler interface.
The IP address is expected in a form accepted by [ParsePrefix]
or generated by [Prefix.MarshalText].
Prefix : database/sql/driver.Validator
Prefix : encoding.BinaryMarshaler
*Prefix : encoding.BinaryUnmarshaler
Prefix : encoding.TextMarshaler
*Prefix : encoding.TextUnmarshaler
Prefix : expvar.Var
Prefix : fmt.Stringer
func MustParsePrefix(s string) Prefix
func ParsePrefix(s string) (Prefix, error)
func PrefixFrom(ip Addr, bits int) Prefix
func Addr.Prefix(b int) (Prefix, error)
func Prefix.Masked() Prefix
func Prefix.Overlaps(o Prefix) bool
Package-Level Functions (total 16)
AddrFrom16 returns the IPv6 address given by the bytes in addr.
An IPv4-mapped IPv6 address is left as an IPv6 address.
(Use Unmap to convert them if needed.)
AddrFrom4 returns the address of the IPv4 address given by the bytes in addr.
AddrFromSlice parses the 4- or 16-byte byte slice as an IPv4 or IPv6 address.
Note that a [net.IP] can be passed directly as the []byte argument.
If slice's length is not 4 or 16, AddrFromSlice returns [Addr]{}, false.
AddrPortFrom returns an [AddrPort] with the provided IP and port.
It does not allocate.
IPv4Unspecified returns the IPv4 unspecified address "0.0.0.0".
IPv6LinkLocalAllNodes returns the IPv6 link-local all nodes multicast
address ff02::1.
IPv6LinkLocalAllRouters returns the IPv6 link-local all routers multicast
address ff02::2.
IPv6Loopback returns the IPv6 loopback address ::1.
IPv6Unspecified returns the IPv6 unspecified address "::".
MustParseAddr calls [ParseAddr](s) and panics on error.
It is intended for use in tests with hard-coded strings.
MustParseAddrPort calls [ParseAddrPort](s) and panics on error.
It is intended for use in tests with hard-coded strings.
MustParsePrefix calls [ParsePrefix](s) and panics on error.
It is intended for use in tests with hard-coded strings.
ParseAddr parses s as an IP address, returning the result. The string
s can be in dotted decimal ("192.0.2.1"), IPv6 ("2001:db8::68"),
or IPv6 with a scoped addressing zone ("fe80::1cc0:3e8c:119f:c2e1%ens18").
ParseAddrPort parses s as an [AddrPort].
It doesn't do any name resolution: both the address and the port
must be numeric.
ParsePrefix parses s as an IP address prefix.
The string can be in the form "192.168.1.0/24" or "2001:db8::/32",
the CIDR notation defined in RFC 4632 and RFC 4291.
IPv6 zones are not permitted in prefixes, and an error will be returned if a
zone is present.
Note that masked address bits are not zeroed. Use Masked for that.
PrefixFrom returns a [Prefix] with the provided IP address and bit
prefix length.
It does not allocate. Unlike [Addr.Prefix], [PrefixFrom] does not mask
off the host bits of ip.
If bits is less than zero or greater than ip.BitLen, [Prefix.Bits]
will return an invalid value -1.
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