create new constexpr for the staleness window for introsets and use it in publishing introsets and intro selection

llarp/constants/path.hpp

@@ -24,6 +24,9 @@ namespace llarp
     constexpr auto intro_spread_slices = 4;
     /// spacing frequency at which we try to build paths for introductions
     constexpr std::chrono::milliseconds intro_path_spread = default_lifetime / intro_spread_slices;
+    /// how long away from expiration in millseconds do we consider an intro to become stale
+    constexpr std::chrono::milliseconds intro_stale_threshold =
+        default_lifetime - intro_path_spread;
     /// Minimum paths to keep around for intros; mainly used at startup (the
     /// spread, above, should be able to maintain more than this number of paths
     /// normally once things are going).

llarp/service/endpoint.cpp

@@ -104,7 +104,7 @@ namespace llarp
       std::set<Introduction, CompareIntroTimestamp> intros;
       if (const auto maybe =
               GetCurrentIntroductionsWithFilter([now](const service::Introduction& intro) -> bool {
-                return not intro.ExpiresSoon(now, path::default_lifetime - path::intro_path_spread);
+                return not intro.ExpiresSoon(now, path::intro_stale_threshold);
               }))
       {
         intros.insert(maybe->begin(), maybe->end());
@@ -735,8 +735,7 @@ namespace llarp
 
       const auto lastEventAt = std::max(m_state->m_LastPublishAttempt, m_state->m_LastPublish);
       const auto next_pub = lastEventAt
-          + (m_state->m_IntroSet.HasStaleIntros(
-                 now, path::default_lifetime - path::intro_path_spread)
+          + (m_state->m_IntroSet.HasStaleIntros(now, path::intro_stale_threshold)
                  ? IntrosetPublishRetryCooldown
                  : IntrosetPublishInterval);