From 54f9e1b44e79f3b0d7555eaf58f1a05d9ad86c1f Mon Sep 17 00:00:00 2001
From: Jeff Becker <jeff@i2p.rocks>
Date: Sat, 1 May 2021 16:25:32 -0400
Subject: [PATCH] make path alignment timeout configuable

adds [network] section parameter called path-alignment-timeout that allows configring the timeout
for optional name lookup + introset lookup + aligned path build, used by tun endpoint dns, provided
as milliseconds.
---
 llarp/config/config.cpp | 15 +++++++++++++++
 llarp/config/config.hpp |  2 ++
 llarp/handlers/tun.cpp  | 22 +++++++++++++++-------
 llarp/handlers/tun.hpp  |  2 ++
 4 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/llarp/config/config.cpp b/llarp/config/config.cpp
index e6deec451..6ce3971a3 100644
--- a/llarp/config/config.cpp
+++ b/llarp/config/config.cpp
@@ -659,6 +659,21 @@ namespace llarp
           m_SRVRecords.push_back(std::move(newSRV));
         });
 
+    conf.defineOption<int>(
+        "network",
+        "path-alignment-timeout",
+        ClientOnly,
+        Comment{
+            "time in milliseconds how long to wait for a path to align to pivot routers",
+            "if not provided a sensible default will be used",
+        },
+        [this](int val) {
+          if (val <= 200)
+            throw std::invalid_argument{
+                "invalid path alignment timeout: " + std::to_string(val) + " <= 200"};
+          m_PathAlignmentTimeout = std::chrono::milliseconds{val};
+        });
+
     // Deprecated options:
     conf.defineOption<std::string>("network", "enabled", Deprecated);
   }
diff --git a/llarp/config/config.hpp b/llarp/config/config.hpp
index 399fac8a2..7fb212df4 100644
--- a/llarp/config/config.hpp
+++ b/llarp/config/config.hpp
@@ -125,6 +125,8 @@ namespace llarp
     std::set<IPRange> m_OwnedRanges;
     std::optional<net::TrafficPolicy> m_TrafficPolicy;
 
+    std::optional<llarp_time_t> m_PathAlignmentTimeout;
+
     // TODO:
     // on-up
     // on-down
diff --git a/llarp/handlers/tun.cpp b/llarp/handlers/tun.cpp
index cc7dd67e5..172479ddd 100644
--- a/llarp/handlers/tun.cpp
+++ b/llarp/handlers/tun.cpp
@@ -131,6 +131,8 @@ namespace llarp
         m_Resolver->Restart();
     }
 
+    constexpr auto DefaultAlignmentTimeout = 10s;
+
     bool
     TunEndpoint::Configure(const NetworkConfig& conf, const DnsConfig& dnsConf)
     {
@@ -167,6 +169,13 @@ namespace llarp
 
       m_BaseV6Address = conf.m_baseV6Address;
 
+      if (conf.m_PathAlignmentTimeout)
+      {
+        m_PathAlignmentTimeout = *conf.m_PathAlignmentTimeout;
+      }
+      else
+        m_PathAlignmentTimeout = DefaultAlignmentTimeout;
+
       for (const auto& item : conf.m_mapAddrs)
       {
         if (not MapAddress(item.second, item.first, false))
@@ -259,8 +268,6 @@ namespace llarp
         return service::Address{itr->second.as_array()};
     }
 
-    constexpr auto TrafficAlignmentTimeout = 10s;
-
     bool
     TunEndpoint::HandleHookedDNSMessage(dns::Message msg, std::function<void(dns::Message)> reply)
     {
@@ -272,7 +279,7 @@ namespace llarp
               SendDNSReply(snode, s, msg, reply, isV6);
             });
       };
-      auto ReplyToLokiDNSWhenReady = [this, reply](
+      auto ReplyToLokiDNSWhenReady = [this, reply, timeout = m_PathAlignmentTimeout](
                                          service::Address addr, auto msg, bool isV6) -> bool {
         using service::Address;
         using service::OutboundContext;
@@ -281,7 +288,7 @@ namespace llarp
             [this, addr, msg, reply, isV6](const Address&, OutboundContext* ctx) {
               SendDNSReply(addr, ctx, msg, reply, isV6);
             },
-            TrafficAlignmentTimeout);
+            timeout);
       };
 
       auto ReplyToDNSWhenReady = [ReplyToLokiDNSWhenReady, ReplyToSNodeDNSWhenReady](
@@ -298,7 +305,8 @@ namespace llarp
         }
       };
 
-      auto ReplyToLokiSRVWhenReady = [this, reply](service::Address addr, auto msg) -> bool {
+      auto ReplyToLokiSRVWhenReady = [this, reply, timeout = m_PathAlignmentTimeout](
+                                         service::Address addr, auto msg) -> bool {
         using service::Address;
         using service::OutboundContext;
 
@@ -312,7 +320,7 @@ namespace llarp
               msg->AddSRVReply(introset.GetMatchingSRVRecords(addr.subdomain));
               reply(*msg);
             },
-            TrafficAlignmentTimeout);
+            timeout);
       };
 
       if (msg.answers.size() > 0)
@@ -924,7 +932,7 @@ namespace llarp
                 }
                 self->SendToOrQueue(addr, pkt.ConstBuffer(), service::ProtocolType::Exit);
               },
-              TrafficAlignmentTimeout);
+              m_PathAlignmentTimeout);
           return;
         }
         bool rewriteAddrs = true;
diff --git a/llarp/handlers/tun.hpp b/llarp/handlers/tun.hpp
index 77054fb6f..f1626d468 100644
--- a/llarp/handlers/tun.hpp
+++ b/llarp/handlers/tun.hpp
@@ -267,6 +267,8 @@ namespace llarp
       std::optional<net::TrafficPolicy> m_TrafficPolicy;
       /// ranges we advetise as reachable
       std::set<IPRange> m_OwnedRanges;
+      /// how long to wait for path alignment
+      llarp_time_t m_PathAlignmentTimeout;
     };
 
   }  // namespace handlers