Enum Attribute 

pub enum Attribute {
    Username(String),
    Priority(Priority),
    UseCandidate,
    IceControlled(u64),
    IceControlling(u64),
    ErrorCode {
        code: u16,
        reason: String,
    },
    XorMappedAddress(SocketAddr),
    Software(String),
    Unknown {
        kind: u16,
        value: Vec<u8>,
    },
}

One STUN attribute, in the profile spec §11.1 lists.

MESSAGE-INTEGRITY and FINGERPRINT are deliberately not variants. They are not attributes a caller chooses to add: they are computed over whatever else is present and must come last, in that order, so Message::encode appends them and nothing else can.

Attribute::Unknown is the hole in that sentence, and it is closed rather than trusted: encoding one whose kind is either of those two types is Error::ReservedAttribute. It is not reachable from the wire — Message::decode matches both types before it ever builds an Unknown — but it is reachable from a caller assembling a message by hand, and a second MESSAGE-INTEGRITY in a message is a message that authenticates as nothing.

Variants

Username(String)

USERNAME (RFC 5389 §15.3), in the direction Peering fixes.

Priority(Priority)

PRIORITY (RFC 8445 §7.1.1) — and note §7.1.1’s rule that this is not the candidate’s own priority but the one it would have as a peer-reflexive candidate (spec §4).

Carried as Priority so the RFC 8839 §5.1 range check applies to a value read off the wire as much as to one read out of SDP: spec §6.2 shows that an unchecked priority is what overflows the pair-priority arithmetic, and a check is a place a peer can put one.

UseCandidate

USE-CANDIDATE (RFC 8445 §7.1.2): a flag, so a zero-length value.

IceControlled(u64)

ICE-CONTROLLED (§7.1.3) carrying the sender’s tiebreaker.

IceControlling(u64)

ICE-CONTROLLING (§7.1.3) carrying the sender’s tiebreaker.

ErrorCode

ERROR-CODE (RFC 5389 §15.6). 487 is the role conflict of RFC 8445 §7.3.1.1.

The code is held to ERROR_CODES in both directions. On decode that means an error response carrying a class §15.6 does not define is a dropped datagram, which costs the transaction a retransmission rather than an immediate failure — the same fail-closed trade the module documentation records for PRIORITY, and only reachable from a peer that is already violating §15.6’s MUST.

Fields

code: u16

The three-digit code, reassembled from §15.6’s class and number.

reason: String

The reason phrase, which is advisory and may be empty.

XorMappedAddress(SocketAddr)

XOR-MAPPED-ADDRESS (RFC 5389 §15.2): where the responder saw the request come from.

Software(String)

SOFTWARE (RFC 5389 §15.10).

sipx does not put one on its own checks — spec §11.1 lists what a check carries and this is not on it, and a version string on every check is bytes on the wire and a gift to a scanner. It is here because a peer may send one and because RFC 5769’s vectors carry one, and a vector that cannot be encoded is a vector that cannot test the encoder.

Unknown

An attribute this profile has no meaning for, kept so the caller can decide.

RFC 5389 §7.3.1 wants a comprehension-required unknown attribute in a request answered with a 420; that is the agent’s decision, not the codec’s, so the bytes survive to it.

Fields

kind: u16

The attribute type.

value: Vec<u8>

Its value, unpadded.

Trait Implementations

impl Clone for Attribute

fn clone(&self) -> Attribute

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Attribute

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

Formats the value using the given formatter.

impl PartialEq for Attribute

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

Tests for self and other values to be equal, and is used by ==.

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

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

impl Eq for Attribute

impl StructuralPartialEq for Attribute