Enum DnsResolveState

pub enum DnsResolveState {
    Init,
    Resolving {
        query_handle: usize,
        start_tsc: TscTimestamp,
    },
    Resolved {
        ip: Ipv4Addr,
    },
    Failed {
        error: DnsError,
    },
}

DNS resolution state machine.

Resolves a hostname to an IPv4 address using smoltcp’s DNS socket.

Variants

Init

Initial state - not started

Resolving

Waiting for DNS response

Fields

query_handle: usize

Query handle from smoltcp

start_tsc: TscTimestamp

When query started (for timeout)

Resolved

Resolution complete

Fields

ip: Ipv4Addr

Resolved IP address

Failed

Resolution failed

Fields

error: DnsError

Error details

Implementations

impl DnsResolveState

pub fn new() -> Self

Create new DNS resolver in init state.

pub fn start(&mut self, query_handle: usize, now_tsc: u64)

Start DNS resolution.

Arguments

• query_handle: Handle returned from smoltcp’s start_query()
• now_tsc: Current TSC timestamp

pub fn resolve(&mut self, ip: Ipv4Addr)

Mark as resolved with IP.

pub fn fail(&mut self, error: DnsError)

Mark as failed.

pub fn step( &mut self, dns_result: Result<Option<Ipv4Addr>, ()>, now_tsc: u64, timeout_ticks: u64, ) -> StepResult

Step the state machine.

Arguments

• dns_result: Result from smoltcp’s get_query_result():
  • Ok(Some(ip)): Resolved
  • Ok(None): Still pending
  • Err(_): Failed
• now_tsc: Current TSC value
• timeout_ticks: DNS timeout in TSC ticks

Returns

• Pending: Still resolving
• Done: Resolved, call ip() to get result
• Timeout: Query timed out
• Failed: Query failed

pub fn query_handle(&self) -> Option<usize>

Get query handle (if resolving).

pub fn ip(&self) -> Option<Ipv4Addr>

Get resolved IP address (if complete).

pub fn error(&self) -> Option<DnsError>

Get error (if failed).

pub fn is_terminal(&self) -> bool

Check if resolution is complete (success or failure).

pub fn is_resolved(&self) -> bool

Check if resolution succeeded.

Trait Implementations

impl Debug for DnsResolveState

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

Formats the value using the given formatter.

impl Default for DnsResolveState

fn default() -> Self

Returns the “default value” for a type.