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I am working in project to create a UDP broadcast programming -

create a system that sends a broadcast of a message alert to all nodes in the rang that are on the network. Each station that receives the message must resend it to other stations on the networks it is connected except the sender one to spread the message.

I created the client.py and the server.py , but I don't know how to make the station Resend the message alert. its the first time i am creating a project in networking programming in python.

#client.py
import socket
client = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP) # UDP
# Enable port reusage so we will be able to run multiple clients and servers on single (host, port).
# Do not use socket.SO_REUSEADDR except you using linux(kernel<3.9): goto https://stackoverflow.com/questions/14388706/how-do-so-reuseaddr-and-so-reuseport-differ for more information.
# For linux hosts all sockets that want to share the same address and port combination must belong to processes that share the same effective user ID!
# So, on linux(kernel>=3.9) you have to run multiple servers and clients under one user to share the same (host, port).
# Thanks to @stevenreddie
client.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
# Enable broadcasting mode
client.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
client.bind(("", 37020))
while True:
# Thanks @seym45 for a fix
data, addr = client.recvfrom(1024)
print("received message: %s"%data)


#server.py 
import socket
import time
server = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
# Enable port reusage so we will be able to run multiple clients and servers on single (host, port).
# Do not use socket.SO_REUSEADDR except you using linux(kernel<3.9): goto https://stackoverflow.com/questions/14388706/how-do-so-reuseaddr-and-so-reuseport-differ for more information.
# For linux hosts all sockets that want to share the same address and port combination must belong to processes that share the same effective user ID!
# So, on linux(kernel>=3.9) you have to run multiple servers and clients under one user to share the same (host, port).
# Thanks to @stevenreddie
server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
# Enable broadcasting mode
server.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
# Set a timeout so the socket does not block
# indefinitely when trying to receive data.
server.settimeout(0.2)
message = b"your very important message"
while True:
server.sendto(message, ('<broadcast>', 37020))
print("message sent!")
time.sleep(1)
Zainab Abd
  • 21
  • 3

1 Answers1

0

You could just call the sendto() from client.py

client2.py (This resends the received message) 

import socket
import time
client = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP) # UDP
client.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
client.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
client.bind(("", 37020))
while True:
   data, addr = client.recvfrom(1024)
   print("received message: %s"%data)
   data = b"RESEND important message"
   client.sendto(data, ('<broadcast>', 37020))
   print("sent", data)
   time.sleep(1)

client.py (Only receives) 

import socket
import time
client = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP) # UDP
client.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
client.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
client.bind(("", 37020))
while True:
   data, addr = client.recvfrom(1024)
   print("received message: %s"%data)
   time.sleep(1)

server.py

import socket
import time
server = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
server.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
server.settimeout(0.2)
message = b"your very important message"
while True:
    server.sendto(message, ('<broadcast>', 37020))
    print("message sent!")
    time.sleep(1)

If all three files are started you get output like this server.py

message sent!
message sent!
message sent!
message sent!
message sent!
message sent!
message sent!

client2.py

received message: b'your very important message'
sent b'RESEND important message'
received message: b'RESEND important message'
sent b'RESEND important message'
received message: b'your very important message'
sent b'RESEND important message'
received message: b'RESEND important message'
sent b'RESEND important message'
received message: b'your very important message'
sent b'RESEND important message'
received message: b'RESEND important message'
sent b'RESEND important message'

client.py

received message: b'your very important message'
received message: b'your very important message'
received message: b'RESEND important message'
received message: b'your very important message'
received message: b'RESEND important message'
received message: b'your very important message'
received message: b'RESEND important message'
yabberth
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