91 lines
3.0 KiB
Rust
91 lines
3.0 KiB
Rust
use crate::wire::IpAddress;
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use crate::socket::{SocketHandle, PollAt};
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use crate::time::{Duration, Instant};
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/// Neighbor dependency.
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///
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/// This enum tracks whether the socket should be polled based on the neighbor it is
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/// going to send packets to.
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#[derive(Debug)]
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enum NeighborState {
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/// Socket can be polled immediately.
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Active,
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/// Socket should not be polled until either `silent_until` passes or `neighbor` appears
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/// in the neighbor cache.
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Waiting {
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neighbor: IpAddress,
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silent_until: Instant,
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}
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}
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impl Default for NeighborState {
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fn default() -> Self {
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NeighborState::Active
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}
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}
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/// Network socket metadata.
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///
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/// This includes things that only external (to the socket, that is) code
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/// is interested in, but which are more conveniently stored inside the socket itself.
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#[derive(Debug, Default)]
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pub struct Meta {
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/// Handle of this socket within its enclosing `SocketSet`.
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/// Mainly useful for debug output.
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pub(crate) handle: SocketHandle,
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/// See [NeighborState](struct.NeighborState.html).
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neighbor_state: NeighborState,
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}
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impl Meta {
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/// Minimum delay between neighbor discovery requests for this particular socket,
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/// in milliseconds.
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///
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/// See also `iface::NeighborCache::SILENT_TIME`.
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pub(crate) const DISCOVERY_SILENT_TIME: Duration = Duration { millis: 3_000 };
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pub(crate) fn poll_at<F>(&self, socket_poll_at: PollAt, has_neighbor: F) -> PollAt
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where F: Fn(IpAddress) -> bool
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{
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match self.neighbor_state {
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NeighborState::Active =>
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socket_poll_at,
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NeighborState::Waiting { neighbor, .. }
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if has_neighbor(neighbor) =>
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socket_poll_at,
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NeighborState::Waiting { silent_until, .. } =>
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PollAt::Time(silent_until)
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}
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}
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pub(crate) fn egress_permitted<F>(&mut self, timestamp: Instant, has_neighbor: F) -> bool
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where F: Fn(IpAddress) -> bool
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{
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match self.neighbor_state {
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NeighborState::Active =>
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true,
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NeighborState::Waiting { neighbor, silent_until } => {
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if has_neighbor(neighbor) {
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net_trace!("{}: neighbor {} discovered, unsilencing",
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self.handle, neighbor);
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self.neighbor_state = NeighborState::Active;
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true
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} else if timestamp >= silent_until {
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net_trace!("{}: neighbor {} silence timer expired, rediscovering", self.handle, neighbor);
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true
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} else {
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false
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}
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}
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}
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}
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pub(crate) fn neighbor_missing(&mut self, timestamp: Instant, neighbor: IpAddress) {
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net_trace!("{}: neighbor {} missing, silencing until t+{}",
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self.handle, neighbor, Self::DISCOVERY_SILENT_TIME);
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self.neighbor_state = NeighborState::Waiting {
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neighbor, silent_until: timestamp + Self::DISCOVERY_SILENT_TIME
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};
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}
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}
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