libp2p: introduce rehoming

1 files changed, 9 insertions, 5 deletions

diff --git a/src/transport/libp2p/mod.rs b/src/transport/libp2p/mod.rs
index a4fefc3..9d1dcc7 100644
--- a/src/transport/libp2p/mod.rs
+++ b/src/transport/libp2p/mod.rs
@@ -32,11 +32,12 @@
 //! all but one are closed a few seconds later (`DUPLICATE_GRACE`, `Book::duplicates`),
 //! by the side with the smaller peer ID: it keeps the direct one with the shortest round
 //! trip (libp2p's ping, on each connection), so a path over the LAN wins over one
-//! through a VPN, whichever opened first. A peer connected directly is dialled again
-//! where it might be reached better (`explore`): at addresses it tells of later (a new
-//! interface: identify pushes them at once), and at all of them when this node gains
-//! an interface. Otherwise a connection made over the WLAN would stay there once
-//! ethernet comes.
+//! through a VPN, whichever opened first; between a relay and a node with a slot on it
+//! too, where a slot on a connection closed is reserved again over the one kept. A
+//! peer connected directly is dialled again where it might be reached better
+//! (`explore`): at addresses it tells of later (a new interface: identify pushes them
+//! at once), and at all of them when this node gains an interface. Otherwise a
+//! connection made over the WLAN would stay there once ethernet comes.
 //!
 //! A relay says so where it publishes its addresses: next to each, the same address
 //! ending in `/p2p-circuit` (where to reserve a slot), which other nodes find in the
@@ -187,6 +188,9 @@ const DUPLICATE_GRACE: Duration = Duration::from_secs(10);
 /// a hole punch under way (`PUNCH_RETRIES`), which takes its tries (up to a QUIC
 /// handshake's 5 s each, three times) on that connection.
 const PUNCH_GRACE: Duration = Duration::from_secs(60);
+/// A slot lost this soon after its relay's duplicate connections were closed moved to
+/// the one kept (`Book::rehoming`).
+const REHOMING_WITHIN: Duration = Duration::from_secs(10);
 /// After libp2p's hole punching gave up on a peer (three tries, as the relayed
 /// connection opened), it tries again after these, the last one over and over: what
 /// failed may have been passing (a NAT's mapping, a busy link). Each time through a new