diff options
| -rw-r--r-- | docs/peers.md | 5 | ||||
| -rw-r--r-- | src/swarm/working_links.rs | 40 |
2 files changed, 28 insertions, 17 deletions
diff --git a/docs/peers.md b/docs/peers.md index 79f2abb..85d65a9 100644 --- a/docs/peers.md +++ b/docs/peers.md @@ -365,8 +365,9 @@ its registry entry ([`swarm/working_links.rs`](../src/swarm/working_links.rs), ` its neighbours by the graph it doesn't reach (`unreached`), once down for four keepalive intervals, and its neighbours it reaches that the graph doesn't link it to (`reached`: a ring going round a member it doesn't reach, a member reaching out from behind NAT), -once up for one; each comes out again after the -other hold; a link the other end records as unreached already isn't recorded again. +once up for four too (a ring goes round a member only while it is away, so a short +absence writes nothing); a link back comes out after one keepalive, a substitute gone +after four; a link the other end records as unreached already isn't recorded again. On a stable swarm the entry has none. A member that went away is recorded as unreached by its neighbours (they can't tell it from a link that broke), and taken out once they reach it again: so a node first asks up to three diff --git a/src/swarm/working_links.rs b/src/swarm/working_links.rs index 13337b9..d0ea41a 100644 --- a/src/swarm/working_links.rs +++ b/src/swarm/working_links.rs @@ -8,9 +8,11 @@ //! records its neighbours by the graph that it doesn't reach (`unreached`), and its //! neighbours it reaches that the graph doesn't link it to (`reached`: a ring that goes //! round a member it doesn't reach, a member behind NAT that reaches out to one the -//! graph doesn't give it), each only once it has stayed so for a while: going down for -//! `DOWN_FOR` keepalive intervals, up for `UP_FOR`, so a link that drops for a -//! keepalive isn't written down, and one back is soon again. A link either end records +//! graph doesn't give it), each only once it has stayed so for a while: `DOWN_FOR` +//! keepalive intervals for a link down, or one the graph doesn't give (a ring goes +//! round a member only while it is away, so a short absence writes nothing), `UP_FOR` +//! for a link up again, so a link that drops for a keepalive isn't written down, and +//! one back is soon again. A link either end records //! as unreached is one that doesn't work; one either records as reached, one that does; //! so a link the other end records as unreached already isn't recorded by this one. //! Only neighbours (`topology::our_neighbours`, those we sync with) count as reached: @@ -43,10 +45,11 @@ use crate::swarm::{reach, topology}; use crate::transport::{ParsedMessage, ProbeReply, ProbeRequest}; /// Keepalive intervals a link stays down before it is recorded so (`unreached`, or out -/// of `reached`): as long as a silent peer takes to be held dormant (`dormant_after`). +/// of `reached`), and a link the graph doesn't give stays up before it is recorded +/// (into `reached`): as long as a silent peer takes to be held dormant +/// (`dormant_after`). const DOWN_FOR: u32 = 4; -/// Keepalive intervals a link stays up before it is recorded so (out of `unreached`, -/// or into `reached`). +/// Keepalive intervals a link stays up before it is recorded so (out of `unreached`). const UP_FOR: u32 = 1; /// Members asked about a member at once at most: of its @@ -355,9 +358,10 @@ fn via( } /// The record to keep: `recorded`, but where a member's link has differed from it as -/// `now_links` says since long enough before `now` (`pending`): down for `DOWN_FOR` -/// keepalive intervals (newly unreached, or no longer reached), up for `UP_FOR` (reached -/// again, or newly reached, or no longer our neighbour by the graph). A link newly +/// `now_links` says since long enough before `now` (`pending`): `DOWN_FOR` keepalive +/// intervals (newly unreached, no longer reached, or newly reached: a substitute +/// neighbour while one is away), `UP_FOR` otherwise (reached again, or no longer our +/// neighbour by the graph). A link newly /// unreached goes in only if `confirmed` has it (all do without): those held long /// enough that it hasn't are returned, to ask others about. fn decide( @@ -387,8 +391,8 @@ fn decide( pending.since.remove(member); continue; } - let down = (unreached && !was_unreached) || (was_reached && !reached); - let hold = keepalive * if down { DOWN_FOR } else { UP_FOR }; + let long = (unreached && !was_unreached) || (was_reached != reached); + let hold = keepalive * if long { DOWN_FOR } else { UP_FOR }; let since = *pending.since.entry(member.clone()).or_insert(now); if now.saturating_duration_since(since) < hold { continue; @@ -431,7 +435,8 @@ mod tests { } /// A link goes into the record once down for `DOWN_FOR` keepalives, not for one; out - /// once up for `UP_FOR`; one reached the graph doesn't give, once up for `UP_FOR`. + /// once up for `UP_FOR`; one reached the graph doesn't give, in and out after + /// `DOWN_FOR`. #[test] fn links_are_recorded_after_their_hold() { let keepalive = Duration::from_secs(5); @@ -510,7 +515,8 @@ mod tests { none ); - // Reached beyond the graph: in after `UP_FOR`; gone: out after `DOWN_FOR`. + // Reached beyond the graph: in after `DOWN_FOR`, not `UP_FOR`; gone: out after + // `DOWN_FOR`. let beyond = links(&[], &["c"]); assert_eq!( decide(&mut pending, &none, &beyond, at(50), keepalive, None).0, @@ -518,14 +524,18 @@ mod tests { ); assert_eq!( decide(&mut pending, &none, &beyond, at(55), keepalive, None).0, + none + ); + assert_eq!( + decide(&mut pending, &none, &beyond, at(70), keepalive, None).0, beyond ); assert_eq!( - decide(&mut pending, &beyond, &none, at(60), keepalive, None).0, + decide(&mut pending, &beyond, &none, at(75), keepalive, None).0, beyond ); assert_eq!( - decide(&mut pending, &beyond, &none, at(80), keepalive, None).0, + decide(&mut pending, &beyond, &none, at(95), keepalive, None).0, none ); } |