login: logins by key capped per user

Review 6: a node remembers the challenges used until they expire, 10 000
at most, and refused every login by key once full. One user holding a
key could make 10 000 logins within five minutes and keep everyone else
out.

A user may now log in by key at most --key-logins-per-user times (100)
on a node within a challenge's lifetime, past which that user waits and
others don't; the 10 000 stay as the cap for all users together. The
lifetime, five minutes until now, is --challenge-lifetime.

1 files changed, 4 insertions, 0 deletions

diff --git a/src/state/mod.rs b/src/state/mod.rs
index 87b7fe7..4fcf413 100644
--- a/src/state/mod.rs
+++ b/src/state/mod.rs
@@ -157,6 +157,10 @@ pub(crate) struct AppState {
     pub(crate) challenges: Arc<std::sync::Mutex<crate::access::challenge::Used>>,
     pub(crate) token_lifetime: Duration,
     pub(crate) session_lifetime: Duration,
+    /// How long a challenge to log in by key is valid, and how many logins by key a user
+    /// may make within it (`access::challenge`).
+    pub(crate) challenge_lifetime: Duration,
+    pub(crate) key_logins_per_user: usize,
     /// Origins whose pages may call this node's open endpoints (`api::cors`).
     pub(crate) cors_origins: Arc<Vec<String>>,
     /// This node's own files, and how much it read and wrote them.