From 8cefa4b2a9fa3fd22489bf80f3d74a8f13842dc7 Mon Sep 17 00:00:00 2001
From: Mark Qvist <mark@unsigned.io>
Date: Tue, 14 Jan 2025 18:24:56 +0100
Subject: [PATCH] Improved resource transfer timing

---
 RNS/Resource.py | 44 ++++++++++++++++++++++++++++++++------------
 1 file changed, 32 insertions(+), 12 deletions(-)

diff --git a/RNS/Resource.py b/RNS/Resource.py
index b0c726af..683b6768 100644
--- a/RNS/Resource.py
+++ b/RNS/Resource.py
@@ -188,8 +188,11 @@ def accept(advertisement_packet, callback=None, progress_callback = None, reques
             resource.consecutive_completed_height = -1
 
             previous_window = resource.link.get_last_resource_window()
+            previous_eifr   = resource.link.get_last_resource_eifr()
             if previous_window:
                 resource.window = previous_window
+            if previous_eifr:
+                resource.previous_eifr = previous_eifr
             
             if not resource.link.has_incoming_resource(resource):
                 resource.link.register_incoming_resource(resource)
@@ -213,7 +216,6 @@ def accept(advertisement_packet, callback=None, progress_callback = None, reques
 
         except Exception as e:
             RNS.log("Could not decode resource advertisement, dropping resource", RNS.LOG_DEBUG)
-            RNS.trace_exception(e) # TODO: Remove debug
             return None
 
     # Create a resource for transmission to a remote destination
@@ -295,6 +297,9 @@ def __init__(self, data, link, advertise=True, auto_compress=True, callback=None
         self.req_sent = 0
         self.req_resp_rtt_rate = 0
         self.rtt_rxd_bytes_at_part_req = 0
+        self.req_data_rtt_rate = 0
+        self.eifr = None
+        self.previous_eifr = None
         self.fast_rate_rounds = 0
         self.very_slow_rate_rounds = 0
         self.request_id = request_id
@@ -465,6 +470,22 @@ def __advertise_job(self):
 
         self.watchdog_job()
 
+    def update_eifr(self):
+        if self.rtt == None:
+            rtt = self.link.rtt
+        else:
+            rtt = self.rtt
+
+        if self.req_data_rtt_rate != 0:
+            expected_inflight_rate = self.req_data_rtt_rate*8
+        else:
+            if self.previous_eifr != None:
+                expected_inflight_rate = self.previous_eifr
+            else:
+                expected_inflight_rate = self.link.establishment_cost*8 / rtt
+
+        self.eifr = expected_inflight_rate
+
     def watchdog_job(self):
         thread = threading.Thread(target=self.__watchdog_job)
         thread.daemon = True
@@ -479,7 +500,6 @@ def __watchdog_job(self):
                 sleep(0.025)
 
             sleep_time = None
-
             if self.status == Resource.ADVERTISED:
                 sleep_time = (self.adv_sent+self.timeout+Resource.PROCESSING_GRACE)-time.time()
                 if sleep_time < 0:
@@ -503,18 +523,17 @@ def __watchdog_job(self):
 
             elif self.status == Resource.TRANSFERRING:
                 if not self.initiator:
+                    retries_used = self.max_retries - self.retries_left
+                    extra_wait = retries_used * Resource.PER_RETRY_DELAY
 
-                    if self.rtt == None:
-                        rtt = self.link.rtt
-                    else:
-                        rtt = self.rtt
+                    self.update_eifr()
+                    expected_tof_remaining = (self.outstanding_parts*self.sdu*8)/self.eifr
 
-                    window_remaining = self.outstanding_parts
+                    if self.req_resp_rtt_rate != 0:
+                        sleep_time = self.last_activity + self.part_timeout_factor*expected_tof_remaining + Resource.RETRY_GRACE_TIME + extra_wait - time.time()
+                    else:
+                        sleep_time = self.last_activity + self.part_timeout_factor*((3*self.sdu)/self.eifr) + Resource.RETRY_GRACE_TIME + extra_wait - time.time()
 
-                    retries_used = self.max_retries - self.retries_left
-                    extra_wait = retries_used * Resource.PER_RETRY_DELAY
-                    sleep_time = self.last_activity + (rtt*(self.part_timeout_factor+window_remaining)) + Resource.RETRY_GRACE_TIME + extra_wait - time.time()
-                    
                     if sleep_time < 0:
                         if self.retries_left > 0:
                             ms = "" if self.outstanding_parts == 1 else "s"
@@ -564,7 +583,7 @@ def __watchdog_job(self):
                         sleep_time = 0.001
 
             if sleep_time == 0:
-                RNS.log("Warning! Link watchdog sleep time of 0!", RNS.LOG_WARNING)
+                RNS.log("Warning! Link watchdog sleep time of 0!", RNS.LOG_DEBUG)
             if sleep_time == None or sleep_time < 0:
                 RNS.log("Timing error, cancelling resource transfer.", RNS.LOG_ERROR)
                 self.cancel()
@@ -781,6 +800,7 @@ def receive_part(self, packet):
 
                         if rtt != 0:
                             self.req_data_rtt_rate = req_transferred/rtt
+                            self.update_eifr()
                             self.rtt_rxd_bytes_at_part_req = self.rtt_rxd_bytes
 
                             if self.req_data_rtt_rate > Resource.RATE_FAST and self.fast_rate_rounds < Resource.FAST_RATE_THRESHOLD: