From e3a716224d3d6d0217f57e345cbf28caf724c867 Mon Sep 17 00:00:00 2001
From: Mark Qvist <mark@unsigned.io>
Date: Tue, 14 Jan 2025 18:17:53 +0100
Subject: [PATCH] Implemented MTU autoconfiguration on interfaces

---
 RNS/Interfaces/Interface.py      | 29 ++++++++++++++++++++++++++++-
 RNS/Interfaces/LocalInterface.py |  4 +++-
 RNS/Interfaces/TCPInterface.py   |  5 ++++-
 3 files changed, 35 insertions(+), 3 deletions(-)

diff --git a/RNS/Interfaces/Interface.py b/RNS/Interfaces/Interface.py
index 580bca4..f025fe1 100755
--- a/RNS/Interfaces/Interface.py
+++ b/RNS/Interfaces/Interface.py
@@ -64,12 +64,14 @@ class Interface:
     IC_BURST_PENALTY         = 5*60
     IC_HELD_RELEASE_INTERVAL = 30
 
+    AUTOCONFIGURE_MTU = False
+
     def __init__(self):
         self.rxb     = 0
         self.txb     = 0
         self.created = time.time()
         self.online  = False
-        self.bitrate = 1e6
+        self.bitrate = 62500
         self.HW_MTU  = None
 
         self.ingress_control = True
@@ -118,6 +120,31 @@ class Interface:
         else:
             return False
 
+    def optimise_mtu(self):
+        if self.AUTOCONFIGURE_MTU:
+            if self.bitrate   > 16_000_000:
+                self.HW_MTU = 262144
+            elif self.bitrate > 8_000_000:
+                self.HW_MTU = 131072
+            elif self.bitrate > 4_000_000:
+                self.HW_MTU = 65536
+            elif self.bitrate > 2_000_000:
+                self.HW_MTU = 32768
+            elif self.bitrate > 1_000_000:
+                self.HW_MTU = 16384
+            elif self.bitrate > 500_000:
+                self.HW_MTU = 8192
+            elif self.bitrate > 250_000:
+                self.HW_MTU = 4096
+            elif self.bitrate > 125_000:
+                self.HW_MTU = 2048
+            elif self.bitrate > 62_500:
+                self.HW_MTU = 1024
+            else:
+                self.HW_MTU = None
+
+        RNS.log(f"{self} hardware MTU set to {self.HW_MTU}", RNS.LOG_DEBUG) # TODO: Remove debug
+
     def age(self):
         return time.time()-self.created
 
diff --git a/RNS/Interfaces/LocalInterface.py b/RNS/Interfaces/LocalInterface.py
index b06a6b3..31195c5 100644
--- a/RNS/Interfaces/LocalInterface.py
+++ b/RNS/Interfaces/LocalInterface.py
@@ -52,6 +52,7 @@ class ThreadingTCPServer(socketserver.ThreadingMixIn, socketserver.TCPServer):
 
 class LocalClientInterface(Interface):
     RECONNECT_WAIT = 8
+    AUTOCONFIGURE_MTU = True
 
     def __init__(self, owner, name, target_port = None, connected_socket=None):
         super().__init__()
@@ -86,7 +87,7 @@ class LocalClientInterface(Interface):
             self.connect()
 
         self.owner   = owner
-        self.bitrate = 1000*1000*1000
+        self.bitrate = 1_000_000_000
         self.online  = True
         self.writing = False
 
@@ -288,6 +289,7 @@ class LocalClientInterface(Interface):
 
 
 class LocalServerInterface(Interface):
+    AUTOCONFIGURE_MTU = True
 
     def __init__(self, owner, bindport=None):
         super().__init__()
diff --git a/RNS/Interfaces/TCPInterface.py b/RNS/Interfaces/TCPInterface.py
index abaecba..ad7e5d3 100644
--- a/RNS/Interfaces/TCPInterface.py
+++ b/RNS/Interfaces/TCPInterface.py
@@ -67,6 +67,7 @@ class ThreadingTCP6Server(socketserver.ThreadingMixIn, socketserver.TCPServer):
 class TCPClientInterface(Interface):
     BITRATE_GUESS = 10*1000*1000
     DEFAULT_IFAC_SIZE = 16
+    AUTOCONFIGURE_MTU = True
 
     RECONNECT_WAIT = 5
     RECONNECT_MAX_TRIES = None
@@ -406,8 +407,9 @@ class TCPClientInterface(Interface):
 
 
 class TCPServerInterface(Interface):
-    BITRATE_GUESS      = 10*1000*1000
+    BITRATE_GUESS     = 10_000_000
     DEFAULT_IFAC_SIZE = 16
+    AUTOCONFIGURE_MTU = True
 
     @staticmethod
     def get_address_for_if(name, bind_port, prefer_ipv6=False):
@@ -528,6 +530,7 @@ class TCPServerInterface(Interface):
         spawned_interface.target_port = str(handler.client_address[1])
         spawned_interface.parent_interface = self
         spawned_interface.bitrate = self.bitrate
+        spawned_interface.optimise_mtu()
         
         spawned_interface.ifac_size = self.ifac_size
         spawned_interface.ifac_netname = self.ifac_netname