Struct XorMappedAddress

pub struct XorMappedAddress;

The XOR-MAPPED-ADDRESS attribute is identical to the MAPPED-ADDRESS attribute, except that the reflexive transport address is obfuscated through the XOR function.

The format of the XOR-MAPPED-ADDRESS is:

  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |0 0 0 0 0 0 0 0|    Family     |         X-Port                |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                X-Address (Variable)
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

The Family field represents the IP address family and is encoded identically to the Family field in MAPPED-ADDRESS.

X-Port is computed by XOR’ing the mapped port with the most significant 16 bits of the magic cookie. If the IP address family is IPv4, X-Address is computed by XOR’ing the mapped IP address with the magic cookie. If the IP address family is IPv6, X-Address is computed by XOR’ing the mapped IP address with the concatenation of the magic cookie and the 96-bit transaction ID. In all cases, the XOR operation works on its inputs in network byte order (that is, the order they will be encoded in the message).

The rules for encoding and processing the first 8 bits of the attribute’s value, the rules for handling multiple occurrences of the attribute, and the rules for processing address families are the same as for MAPPED-ADDRESS.

Note: XOR-MAPPED-ADDRESS and MAPPED-ADDRESS differ only in their encoding of the transport address. The former encodes the transport address by XOR’ing it with the magic cookie. The latter encodes it directly in binary. RFC3489 originally specified only MAPPED- ADDRESS. However, deployment experience found that some NATs rewrite the 32-bit binary payloads containing the NAT’s public IP address, such as STUN’s MAPPED-ADDRESS attribute, in the well-meaning but misguided attempt to provide a generic Application Layer Gateway (ALG) function. Such behavior interferes with the operation of STUN and also causes failure of STUN’s message-integrity checking.

Trait Implementations

impl<'a> Property<'a> for XorMappedAddress

type Error = StunError

type Inner = SocketAddr

current attribute inner type.

fn kind() -> AttrKind

get current attribute type.

fn into(value: Self::Inner, buf: &mut BytesMut, token: &[u8])

write the current attribute to the buffer.

fn try_from(buf: &'a [u8], token: &'a [u8]) -> Result<Self::Inner, Self::Error>

convert buffer to current attribute.