diff options
Diffstat (limited to 'pkg/tcpip/header/ipv4.go')
| -rw-r--r-- | pkg/tcpip/header/ipv4.go | 24 |
1 files changed, 22 insertions, 2 deletions
diff --git a/pkg/tcpip/header/ipv4.go b/pkg/tcpip/header/ipv4.go index e5360e7c1..680eafd16 100644 --- a/pkg/tcpip/header/ipv4.go +++ b/pkg/tcpip/header/ipv4.go @@ -38,7 +38,8 @@ const ( // IPv4Fields contains the fields of an IPv4 packet. It is used to describe the // fields of a packet that needs to be encoded. type IPv4Fields struct { - // IHL is the "internet header length" field of an IPv4 packet. + // IHL is the "internet header length" field of an IPv4 packet. The value + // is in bytes. IHL uint8 // TOS is the "type of service" field of an IPv4 packet. @@ -100,6 +101,11 @@ const ( // IPv4Version is the version of the ipv4 protocol. IPv4Version = 4 + // IPv4AllSystems is the all systems IPv4 multicast address as per + // IANA's IPv4 Multicast Address Space Registry. See + // https://www.iana.org/assignments/multicast-addresses/multicast-addresses.xhtml. + IPv4AllSystems tcpip.Address = "\xe0\x00\x00\x01" + // IPv4Broadcast is the broadcast address of the IPv4 procotol. IPv4Broadcast tcpip.Address = "\xff\xff\xff\xff" @@ -138,7 +144,7 @@ func IPVersion(b []byte) int { } // HeaderLength returns the value of the "header length" field of the ipv4 -// header. +// header. The length returned is in bytes. func (b IPv4) HeaderLength() uint8 { return (b[versIHL] & 0xf) * 4 } @@ -158,6 +164,11 @@ func (b IPv4) Flags() uint8 { return uint8(binary.BigEndian.Uint16(b[flagsFO:]) >> 13) } +// More returns whether the more fragments flag is set. +func (b IPv4) More() bool { + return b.Flags()&IPv4FlagMoreFragments != 0 +} + // TTL returns the "TTL" field of the ipv4 header. func (b IPv4) TTL() uint8 { return b[ttl] @@ -304,3 +315,12 @@ func IsV4MulticastAddress(addr tcpip.Address) bool { } return (addr[0] & 0xf0) == 0xe0 } + +// IsV4LoopbackAddress determines if the provided address is an IPv4 loopback +// address (belongs to 127.0.0.1/8 subnet). +func IsV4LoopbackAddress(addr tcpip.Address) bool { + if len(addr) != IPv4AddressSize { + return false + } + return addr[0] == 0x7f +} |