From befb52d014cef3f80858e427bd257a1c20e8774a Mon Sep 17 00:00:00 2001
From: Youngjoon Lee <5462944+youngjoon-lee@users.noreply.github.com>
Date: Tue, 13 Aug 2024 01:14:27 +0900
Subject: [PATCH] optimize: exclude the node who sent the message when
 gossiping the message

---
 mixnet/protocol/gossip.py  | 11 ++++++-----
 mixnet/protocol/nomssip.py | 15 +++++++++------
 2 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/mixnet/protocol/gossip.py b/mixnet/protocol/gossip.py
index 2203cee..04a1e60 100644
--- a/mixnet/protocol/gossip.py
+++ b/mixnet/protocol/gossip.py
@@ -61,10 +61,10 @@ class Gossip:
             msg = await conn.recv()
             if self.__check_update_cache(msg):
                 continue
-            await self._process_inbound_msg(msg)
+            await self._process_inbound_msg(msg, conn)
 
-    async def _process_inbound_msg(self, msg: bytes):
-        await self._gossip(msg)
+    async def _process_inbound_msg(self, msg: bytes, received_from: DuplexConnection):
+        await self._gossip(msg, [received_from])
         await self.handler(msg)
 
     async def publish(self, msg: bytes):
@@ -82,12 +82,13 @@ class Gossip:
             # which means that we consider that this publisher node received the message.
             await self.handler(msg)
 
-    async def _gossip(self, msg: bytes):
+    async def _gossip(self, msg: bytes, excludes: list[DuplexConnection] = []):
         """
         Gossip a message to all peers connected to this node.
         """
         for conn in self.conns:
-            await conn.send(msg)
+            if conn not in excludes:
+                await conn.send(msg)
 
     def __check_update_cache(self, packet: bytes) -> bool:
         """
diff --git a/mixnet/protocol/nomssip.py b/mixnet/protocol/nomssip.py
index 588a92e..bd4e96a 100644
--- a/mixnet/protocol/nomssip.py
+++ b/mixnet/protocol/nomssip.py
@@ -6,6 +6,7 @@ from typing import Awaitable, Callable, Self, override
 
 from framework import Framework
 from protocol.connection import (
+    DuplexConnection,
     MixSimplexConnection,
     SimplexConnection,
 )
@@ -56,18 +57,18 @@ class Nomssip(Gossip):
         )
 
     @override
-    async def _process_inbound_msg(self, msg: bytes):
+    async def _process_inbound_msg(self, msg: bytes, received_from: DuplexConnection):
         packet = FlaggedPacket.from_bytes(msg)
         match packet.flag:
             case FlaggedPacket.Flag.NOISE:
                 # Drop noise packet
                 return
             case FlaggedPacket.Flag.REAL:
-                await self.__gossip_flagged_packet(packet)
+                await self.__gossip_flagged_packet(packet, [received_from])
                 await self.handler(packet.message)
 
     @override
-    async def _gossip(self, msg: bytes):
+    async def _gossip(self, msg: bytes, excludes: list[DuplexConnection] = []):
         """
         Gossip a message to all connected peers with prepending a message flag
         """
@@ -75,13 +76,15 @@ class Nomssip(Gossip):
         assert len(msg) == self.config.msg_size, f"{len(msg)} != {self.config.msg_size}"
 
         packet = FlaggedPacket(FlaggedPacket.Flag.REAL, msg)
-        await self.__gossip_flagged_packet(packet)
+        await self.__gossip_flagged_packet(packet, excludes)
 
-    async def __gossip_flagged_packet(self, packet: FlaggedPacket):
+    async def __gossip_flagged_packet(
+        self, packet: FlaggedPacket, excludes: list[DuplexConnection] = []
+    ):
         """
         An internal method to send a flagged packet to all connected peers
         """
-        await super()._gossip(packet.bytes())
+        await super()._gossip(packet.bytes(), excludes)
 
 
 class FlaggedPacket: