Enum netstack3_core::udp::UdpRemotePort

pub enum UdpRemotePort {
    Set(NonZeroU16),
    Unset,
}

The remote port for a UDP socket.

Variants

Set(NonZeroU16)

The remote port is set to the following value.

Unset

The remote port is unset (i.e. “0”) value. An unset remote port is treated specially in a few places:

1. Attempting to send to an unset remote port results in a [UdpSerializeError::RemotePortUnset] error. Note that this behavior diverges from Linux, which does allow sending to a remote_port of 0 (supported by send but not send_to). The rationale for this divergence originates from RFC 8085 Section 5.1:

   A UDP sender SHOULD NOT use a source port value of zero. A source port number that cannot be easily determined from the address or payload type provides protection at the receiver from data injection attacks by off-path devices. A UDP receiver SHOULD NOT bind to port zero.

   Applications SHOULD implement receiver port and address checks at the application layer or explicitly request that the operating system filter the received packets to prevent receiving packets with an arbitrary port. This measure is designed to provide additional protection from data injection attacks from an off-path source (where the port values may not be known).

Combined, these two stanzas recommend hosts discard incoming traffic destined to remote port 0 for security reasons. Thus we choose to not allow hosts to send such packets under the assumption that it will be dropped by the receiving end.

2. A socket connected to a remote host on port 0 will not receive any packets from the remote host. This is because the [BoundSocketMap::lookup] implementation only delivers packets that specify a remote port to connected sockets with an exact match. Further, packets that don’t specify a remote port are only delivered to listener sockets. This diverges from Linux (which treats a remote_port of 0) as wild card. If and when a concrete need for such behavior is identified, the [BoundSocketMap] lookup behavior can be adjusted accordingly.

Trait Implementations

impl Clone for UdpRemotePort

fn clone(&self) -> UdpRemotePort

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for UdpRemotePort

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<NonZero<u16>> for UdpRemotePort

fn from(p: NonZeroU16) -> Self

Converts to this type from the input type.

impl From<UdpRemotePort> for u16

fn from(p: UdpRemotePort) -> Self

Converts to this type from the input type.

impl From<u16> for UdpRemotePort

fn from(p: u16) -> Self

Converts to this type from the input type.

impl Hash for UdpRemotePort

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for UdpRemotePort

fn eq(&self, other: &UdpRemotePort) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for UdpRemotePort

impl Eq for UdpRemotePort

impl StructuralPartialEq for UdpRemotePort