From 6521f839cdf9a10e4a21d98cb5963dcf0ad584b8 Mon Sep 17 00:00:00 2001
From: Mark Qvist <mark@unsigned.io>
Date: Thu, 10 Oct 2024 17:06:43 +0200
Subject: [PATCH] Fixed resource transfers hanging for a long time over slow
 links if proof packet is lost

---
 RNS/Resource.py  |  7 +++++++
 RNS/Transport.py | 11 ++++++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/RNS/Resource.py b/RNS/Resource.py
index eb95114..d61dbf2 100644
--- a/RNS/Resource.py
+++ b/RNS/Resource.py
@@ -118,6 +118,7 @@ class Resource:
 
     PART_TIMEOUT_FACTOR           = 4
     PART_TIMEOUT_FACTOR_AFTER_RTT = 2
+    PROOF_TIMEOUT_FACTOR          = 3
     MAX_RETRIES                   = 16
     MAX_ADV_RETRIES               = 4
     SENDER_GRACE_TIME             = 10.0
@@ -532,6 +533,10 @@ class Resource:
                         sleep_time = 0.001
 
             elif self.status == Resource.AWAITING_PROOF:
+                # Decrease timeout factor since proof packets are
+                # significantly smaller than full req/resp roundtrip
+                self.timeout_factor = Resource.PROOF_TIMEOUT_FACTOR
+
                 sleep_time = self.last_part_sent + (self.rtt*self.timeout_factor+self.sender_grace_time) - time.time()
                 if sleep_time < 0:
                     if self.retries_left <= 0:
@@ -623,6 +628,7 @@ class Resource:
                 proof_data = self.hash+proof
                 proof_packet = RNS.Packet(self.link, proof_data, packet_type=RNS.Packet.PROOF, context=RNS.Packet.RESOURCE_PRF)
                 proof_packet.send()
+                RNS.Transport.cache(proof_packet, force_cache=True)
             except Exception as e:
                 RNS.log("Could not send proof packet, cancelling resource", RNS.LOG_DEBUG)
                 RNS.log("The contained exception was: "+str(e), RNS.LOG_DEBUG)
@@ -919,6 +925,7 @@ class Resource:
 
             if self.sent_parts == len(self.parts):
                 self.status = Resource.AWAITING_PROOF
+                self.retries_left = 3
 
             if self.__progress_callback != None:
                 try:
diff --git a/RNS/Transport.py b/RNS/Transport.py
index 51c7b36..2338383 100755
--- a/RNS/Transport.py
+++ b/RNS/Transport.py
@@ -1738,7 +1738,16 @@ class Transport:
                         if link.link_id == packet.destination_hash:
                             if link.attached_interface == packet.receiving_interface:
                                 packet.link = link
-                                link.receive(packet)
+                                if packet.context == RNS.Packet.CACHE_REQUEST:
+                                    cached_packet = Transport.get_cached_packet(packet.data)
+                                    if cached_packet != None:
+                                        cached_packet.unpack()
+                                        RNS.Packet(destination=link, data=cached_packet.data,
+                                                   packet_type=cached_packet.packet_type, context=cached_packet.context).send()
+
+                                    Transport.jobs_locked = False
+                                else:
+                                    link.receive(packet)
                             else:
                                 # In the strange and rare case that an interface
                                 # is partly malfunctioning, and a link-associated