From e787165da931cabf1669eb0c67f84cb32c4b68bc Mon Sep 17 00:00:00 2001
From: Jeff Becker <jeff@i2p.rocks>
Date: Thu, 13 Dec 2018 07:27:14 -0500
Subject: [PATCH] expire old snode sessions

---
 llarp/exit/session.cpp     | 23 +++++++++++++++++++----
 llarp/exit/session.hpp     |  5 +++++
 llarp/service/endpoint.cpp | 11 +++++++++++
 3 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/llarp/exit/session.cpp b/llarp/exit/session.cpp
index 009a3bbe2..e7324de09 100644
--- a/llarp/exit/session.cpp
+++ b/llarp/exit/session.cpp
@@ -13,6 +13,7 @@ namespace llarp
         , m_ExitRouter(router)
         , m_WritePacket(writepkt)
         , m_Counter(0)
+        , m_LastUse(0)
     {
       r->crypto.identity_keygen(m_ExitIdentity);
     }
@@ -76,10 +77,10 @@ namespace llarp
     bool
     BaseSession::HandleGotExit(llarp::path::Path* p, llarp_time_t b)
     {
+      m_LastUse = router->Now();
       if(b == 0)
-      {
         llarp::LogInfo("obtained an exit via ", p->Endpoint());
-      }
+
       return true;
     }
 
@@ -88,7 +89,13 @@ namespace llarp
     {
       (void)p;
       if(m_WritePacket)
-        return m_WritePacket(pkt);
+      {
+        if(!m_WritePacket(pkt))
+          return false;
+        m_LastUse = router->Now();
+        return true;
+      }
+
       return false;
     }
 
@@ -133,9 +140,16 @@ namespace llarp
       return AvailablePaths(llarp::path::ePathRoleExit) > 0;
     }
 
+    bool
+    BaseSession::IsExpired(llarp_time_t now) const
+    {
+      return m_LastUse && now > m_LastUse && now - m_LastUse > LifeSpan;
+    }
+
     bool
     BaseSession::FlushUpstreamTraffic()
     {
+      auto now  = router->Now();
       auto path = PickRandomEstablishedPath(llarp::path::ePathRoleExit);
       if(!path)
       {
@@ -151,7 +165,8 @@ namespace llarp
         {
           auto& msg = queue.front();
           msg.S     = path->NextSeqNo();
-          path->SendRoutingMessage(&msg, router);
+          if(path->SendRoutingMessage(&msg, router))
+            m_LastUse = now;
           queue.pop_front();
         }
       }
diff --git a/llarp/exit/session.hpp b/llarp/exit/session.hpp
index 0313ef851..c2ca86a8a 100644
--- a/llarp/exit/session.hpp
+++ b/llarp/exit/session.hpp
@@ -16,6 +16,7 @@ namespace llarp
     struct BaseSession : public llarp::path::Builder
     {
       static constexpr size_t MaxUpstreamQueueLength = 256;
+      static constexpr llarp_time_t LifeSpan         = 60 * 10 * 1000;
 
       BaseSession(const llarp::RouterID& exitRouter,
                   std::function< bool(llarp_buffer_t) > writepkt,
@@ -48,6 +49,9 @@ namespace llarp
         return m_ExitRouter;
       }
 
+      bool
+      IsExpired(llarp_time_t now) const;
+
      protected:
       llarp::RouterID m_ExitRouter;
       std::function< bool(llarp_buffer_t) > m_WritePacket;
@@ -72,6 +76,7 @@ namespace llarp
       TieredQueue_t m_Upstream;
       uint64_t m_Counter;
       llarp::SecretKey m_ExitIdentity;
+      llarp_time_t m_LastUse;
     };
 
     struct ExitSession final : public BaseSession
diff --git a/llarp/service/endpoint.cpp b/llarp/service/endpoint.cpp
index 2c6f2c102..1af523a0e 100644
--- a/llarp/service/endpoint.cpp
+++ b/llarp/service/endpoint.cpp
@@ -142,6 +142,17 @@ namespace llarp
       {
         RegenAndPublishIntroSet(now);
       }
+      // expire snode sessions
+      {
+        auto itr = m_SNodeSessions.begin();
+        while(itr != m_SNodeSessions.end())
+        {
+          if(itr->second->IsExpired(now))
+            itr = m_SNodeSessions.erase(itr);
+          else
+            ++itr;
+        }
+      }
       // expire pending tx
       {
         std::set< service::IntroSet > empty;