Enum Error 

#[non_exhaustive]
pub enum Error {
    InvalidConfig {
        field: &'static str,
        reason: &'static str,
    },
    InvalidCancellation {
        reason: &'static str,
    },
    TransportNotConfigured {
        transport: &'static str,
    },
    Io(Error),
    EndpointClosed,
    EndpointDraining,
    RuntimeUnavailable,
    Overloaded {
        peer: SocketAddr,
    },
    PolicyRejected {
        reason: String,
    },
    ProtectedPolicyHeader {
        name: String,
    },
    SourceAdmissionCapacity {
        max: usize,
        attempted: usize,
    },
    NoVia,
    Build(BuildError),
    Tls(TlsError),
    Quic(QuicError),
    NoTransaction,
    KeepaliveRefused,
    KeepaliveUnanswered,
    ConnectionClosed,
    Unresolvable(Vec<u8>),
    UnsupportedTransport(&'static str),
    ConnectionCapacity {
        max: usize,
    },
    Capture {
        path: String,
        source: Error,
    },
    TcpFallbackUnavailable {
        size: usize,
        limit: usize,
        source: Box<Error>,
    },
    TooLarge {
        size: usize,
        limit: usize,
    },
}

What can go wrong in the transport layer.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

InvalidConfig

Endpoint configuration cannot create a bounded, live runtime.

Fields

field: &'static str

The public configuration field that is invalid.

reason: &'static str

Its required range.

InvalidCancellation

An outgoing transaction cannot be cancelled as requested.

Fields

reason: &'static str

Which invariant the request did not satisfy.

TransportNotConfigured

An outbound request selected a listener kind this endpoint did not configure.

Fields

transport: &'static str

Stable upper-case transport spelling.

Io(Error)

A socket operation failed.

EndpointClosed

The endpoint loop has stopped.

EndpointDraining

Graceful drain has closed admission for requests which establish a dialog.

RuntimeUnavailable

An in-process endpoint was constructed without an entered Tokio runtime.

Overloaded

The next hop asked this endpoint to reduce traffic and this request was not admitted.

Fields

peer: SocketAddr

The downstream server whose active report caused the rejection.

PolicyRejected

A configured pre-transaction policy refused the request.

Fields

reason: String

Host-supplied, non-secret reason.

ProtectedPolicyHeader

A policy attempted to add a stack-owned identity, routing, authentication or framing field.

Fields

name: String

Canonical field name.

SourceAdmissionCapacity

A live source-admission replacement exceeded the configured scan bound.

Fields

max: usize

Configured maximum number of prefixes in one generation.

attempted: usize

Number of prefixes in the refused replacement.

NoVia

A request could not be sent because it has no usable Via, so no transaction could be keyed on it and no response could ever be matched.

Build(BuildError)

A message could not be built.

Tls(TlsError)

TLS could not be established or verified.

A sips: request that reaches this has failed. There is deliberately no path from here to a cleartext retry: a downgrade would defeat exactly what the scheme asked for.

Quic(QuicError)

QUIC authentication, negotiation, or connection failure.

NoTransaction

A response was given for a transaction that no longer exists.

Almost always means the application took longer to answer than crate::Config::unanswered_limit allows. Reported rather than swallowed: an application told its 200 OK went out, when it did not, believes a call is up while the caller has already timed out.

KeepaliveRefused

A keep-alive was answered with a STUN Binding Error Response (RFC 5626 §4.4.2).

§4.4.2 says the flow “is considered failed” — a refused keep-alive is a stronger signal than an unanswered one, since something is there and it does not want this flow.

KeepaliveUnanswered

A keep-alive went unanswered (RFC 5626 §4.4.1, §4.4.2).

§4.4.1: “If a pong is not received within 10 seconds after sending a ping … then the client MUST treat the flow as failed.”

ConnectionClosed

The connection a keep-alive was sent on closed before it was answered.

Unresolvable(Vec<u8>)

A URI that resolved to no usable candidate (RFC 3263).

UnsupportedTransport(&'static str)

A transport that is declared but not yet implemented.

ConnectionCapacity

Every configured live connection slot is still occupied.

Fields

max: usize

The configured live-task limit.

Capture

A capture file could not be opened (docs/specs/sip-transport.md §13).

Reported from bind rather than swallowed, because the alternative is an endpoint that starts, appears to be recording, and writes nothing — the same failure as a silent discard, one level up. The path is named because a permission or directory mistake is the usual cause.

Fields

path: String

Where the capture was to be written.

source: Error

Why it could not be.

TcpFallbackUnavailable

An oversized UDP request selected the mandatory TCP fallback, but TCP could not be used.

The concrete cause is retained so connection refusal, capacity and endpoint shutdown stay distinguishable. There is deliberately no retry over UDP after this error.

Fields

size: usize

Serialized request size that required the switch.

limit: usize

RFC 3261 §18.1.1’s derived limit for this path.

source: Box<Error>

Why the selected TCP send failed.

TooLarge

A datagram larger than the path MTU on an unreliable transport (RFC 3261 §18.1.1).

Named rather than truncated: a truncated SIP message is a security problem, not a degraded one.

Fields

size: usize

How big the message is.

limit: usize

The configured limit.

Trait Implementations

impl Debug for Error

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

Formats the value using the given formatter.

impl Display for Error

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

Formats the value using the given formatter.

impl Error for Error

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl From<BuildError> for Error

fn from(source: BuildError) -> Self

Converts to this type from the input type.

impl From<Error> for Error

fn from(source: Error) -> Self

Converts to this type from the input type.

impl From<QuicError> for Error

fn from(source: QuicError) -> Self

Converts to this type from the input type.

impl From<TlsError> for Error

fn from(source: TlsError) -> Self

Converts to this type from the input type.