From 2de4bb79bb9fa3bfa7d2aec48da2061c044cc6eb Mon Sep 17 00:00:00 2001
From: Quoc Dao <quoc.dao@student.reutlingen-university.de>
Date: Thu, 25 Jan 2024 20:30:57 +0100
Subject: [PATCH] broadcast -> multicast
---
client.py | 27 ++++++++++-----------
server.py | 70 +++++++++++++++++++++++++++++++------------------------
2 files changed, 54 insertions(+), 43 deletions(-)
diff --git a/client.py b/client.py
index d2952bf..494c508 100644
--- a/client.py
+++ b/client.py
@@ -2,16 +2,17 @@ import socket
import threading
from datetime import datetime
+MULTICAST_GROUP_IP = '224.1.1.1'
+
# Broadcast address and port
-BROADCAST_IP = "192.168.0.255"
-BROADCAST_PORT = 5973
+
+CLIENT_MULTICAST_PORT = 5973
# Local host information
MY_HOST = socket.gethostname()
MY_IP = socket.gethostbyname(MY_HOST)
-
class Client():
def __init__(self):
self.currentLeader = ''
@@ -23,23 +24,23 @@ class Client():
print(f'[{current_date_time}] {msg}')
# dynamic discoverey: client sends request to server group and gets the IP of server as reply
- def BroadcastSendAndReceive(self):
-
- message = 'New client wants to connect: ' + MY_IP
-
+ def MulticastSendAndReceive(self):
# Create a UDP socket
- broadcast_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
- # Send message on broadcast address
- broadcast_socket.sendto(str.encode(message), (BROADCAST_IP, BROADCAST_PORT))
+ multicast_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
- # Send broadcast message
+ # Set the time-to-live for messages to 1 so they do not go past the local network segment
+ multicast_socket.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 1)
+
+ # Send message on multicast address
+ message = 'New client wants to connect: ' + MY_IP
+ multicast_socket.sendto(str.encode(message), (MULTICAST_GROUP_IP, CLIENT_MULTICAST_PORT))
self.printwt("Sent my IP to server group")
while True:
try:
# receive reply data (server IP) from the other participants
- reply, addr = broadcast_socket.recvfrom(1024)
+ reply, addr = multicast_socket.recvfrom(1024)
if reply:
# decode received data
@@ -82,6 +83,6 @@ class Client():
if __name__ == "__main__":
client = Client()
- thread1 = threading.Thread(target = client.BroadcastSendAndReceive)
+ thread1 = threading.Thread(target = client.MulticastSendAndReceive)
thread1.start()
thread1.join()
\ No newline at end of file
diff --git a/server.py b/server.py
index 0894877..e563590 100644
--- a/server.py
+++ b/server.py
@@ -2,14 +2,15 @@ import socket
import threading
from datetime import datetime
import time
+import struct
-BROADCAST_IP = "192.168.0.255"
+MULTICAST_GROUP_IP = '224.1.1.1'
# Listening port Server Discovery
-SERVER_BROADCAST_PORT = 5974
+SERVER_MULTICAST_PORT = 5974
# Listening port Client Discovery
-CLIENT_BROADCAST_PORT = 5973
+CLIENT_MULTICAST_PORT = 5973
# Local host information
MY_HOST = socket.gethostname()
@@ -34,22 +35,26 @@ class Server():
print("Group view is:", self.serverList)
- #This function enables the server to listen to the server broadcast port and reply the ip address
- def BroadcastListenAndReply(self):
+ #This function enables the server to listen to the server multicast port and reply the ip address
+ def MulticastListenAndReply(self):
# if my IP is not in the server list add it
if MY_IP not in self.serverList:
self.serverList.append(MY_IP)
# create socket bind to server address
- broadcast_listen_sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
- broadcast_listen_sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
- broadcast_listen_sock.bind((MY_IP, SERVER_BROADCAST_PORT))
+ multicast_listen_sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+ multicast_listen_sock.bind(('', SERVER_MULTICAST_PORT))
+
+ # tell the os to add the socket to the multicast group
+ multicast_group = socket.inet_aton(MULTICAST_GROUP_IP)
+ mreg = struct.pack('4sL', multicast_group, socket.INADDR_ANY)
+ multicast_listen_sock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreg)
while True:
- data, address = broadcast_listen_sock.recvfrom(1024)
+ data, address = multicast_listen_sock.recvfrom(1024)
if data:
newServer_address = data.decode()
@@ -62,7 +67,7 @@ class Server():
self.serverList.append(newServer_address)
reply_message = MY_IP
- broadcast_listen_sock.sendto(str.encode(reply_message), address)
+ multicast_listen_sock.sendto(str.encode(reply_message), address)
self.printwt('Replied my IP to new participant')
@@ -73,19 +78,20 @@ class Server():
self.printwt(f'The current leader IP is: {self.leader_IP}')
- #this function enables the server to send a broadcast to the server group and receive the answers of existing members
- def BroadcastSendAndReceive(self):
+ #this function enables the server to send a multicast to the server group and receive the answers of existing members
+ def MulticastSendAndReceive(self):
# create socket
- broadcast_group = (BROADCAST_IP, SERVER_BROADCAST_PORT)
- broadcast_send_sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
- broadcast_send_sock.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
- broadcast_send_sock.settimeout(2)
+ multicast_group = (MULTICAST_GROUP_IP, SERVER_MULTICAST_PORT)
+ multicast_send_sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+ # Set a timeout so the socket does not block indefinitely when trying to receive data.
+ multicast_send_sock.settimeout(2)
- # ...
+ # Set the time-to-live for messages to 1 so they do not go past the local network segment.
+ multicast_send_sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 1)
message = MY_IP
- broadcast_send_sock.sendto(message.encode(), broadcast_group)
+ multicast_send_sock.sendto(message.encode(), multicast_group)
self.printwt("Sent my IP to server group")
# if my IP is not in the server list add it
@@ -106,7 +112,7 @@ class Server():
try:
# receive reply data from the other participants
- reply, address = broadcast_send_sock.recvfrom(1024)
+ reply, address = multicast_send_sock.recvfrom(1024)
if reply:
reply_address = reply.decode()
@@ -126,7 +132,7 @@ class Server():
break
if num_responses == 1:
- broadcast_send_sock.close()
+ multicast_send_sock.close()
self.isLeader = True
self.leader_IP = MY_IP # Hier wird die IP-Adresse des Leaders zugewiesen
self.printwt(f'I am the only server in the system, so the leader IP is: {self.leader_IP}')
@@ -136,19 +142,23 @@ class Server():
self.print_group_view()
- # Listen to client broadcast (request) and reply with Server IP
+ # Listen to client multicast (request) and reply with Server IP
def ListenForClientAndReply(self):
# Create a UDP socket
listen_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
- # Set the socket to broadcast and enable reusing addresses
- listen_socket.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
+ # Enable reusing addresses
listen_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
# Bind socket to address and port
- listen_socket.bind((MY_IP, CLIENT_BROADCAST_PORT))
+ listen_socket.bind((MY_IP, CLIENT_MULTICAST_PORT))
+
+ # tell the os to add the socket to the multicast group
+ multicast_group = socket.inet_aton(MULTICAST_GROUP_IP)
+ mreg = struct.pack('4sL', multicast_group, socket.INADDR_ANY)
+ listen_socket.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreg)
- # print("Listening to broadcast messages")
+ # print("Listening to multicast messages")
- # Receiving broadcast massage
+ # Receiving multicast massage
while True:
data, addr = listen_socket.recvfrom(1024)
@@ -169,13 +179,13 @@ class Server():
data = client_socket.recv(1024)
if not data:
break
- self.broadcast(data, client_socket)
+ self.multicast(data, client_socket)
except:
self.clients.remove(client_socket)
break
- def broadcast(self, message, sender_socket):
+ def multicast(self, message, sender_socket):
for client in self.clients:
try:
if client != sender_socket:
@@ -188,10 +198,10 @@ class Server():
if __name__== '__main__':
server = Server()
- thread2 = threading.Thread(target = server.BroadcastListenAndReply)
+ thread2 = threading.Thread(target = server.MulticastListenAndReply)
thread2.start()
- thread3 = threading.Thread(target = server.BroadcastSendAndReceive)
+ thread3 = threading.Thread(target = server.MulticastSendAndReceive)
thread3.start()
thread1 = threading.Thread(target = server.ListenForClientAndReply)
--
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