Python raw socket listening for UDP packets; only half of the packets received

Question

I am trying to create a raw socket in Python that listens for UDP packets only:

import socket
s = socket.socket(socket.AF_INET, socket.SOCK_RAW,         


        

Answer 1

Solved it in kind of a silly manner; please let me know if there is another way, and I will change the accepted answer.

The solution is simply to use two sockets bound on the same port; one raw, one not raw:

import socket, select
s1 = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s1.bind(('0.0.0.0', 1337))
s2 = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_UDP)
s2.bind(('0.0.0.0', 1337))
while True:
    r, w, x = select.select([s1, s2], [], [])
    for i in r:
        print i, i.recvfrom(131072)

This makes the "Destination unreachable" ICMP packets go away and makes all packets go through fine. I think the operating system wants a non-raw socket listening on the port for things to go well, and then any raw sockets listening on that same port will receive copies of the packets.