How can i avoid mulitple raw socket bind to the same ip address?

Question

Actually, if i create multiple RAW sockets with the same IP Address. I could bind all of them, and consequently packets are received by all the sockets.

Is there any way that could be avoided, such that the other process trying to bind the same ip address receives an error?

I am using a raw socket

#include <sys/socket.h>
#include <netinet/in.h>
raw_socket = socket(AF_INET, SOCK_RAW, int protocol);

In Man Page raw(7)

A raw socket can be bound to a specific local address using the bind(2) call. If it isn't bound all packets with the specified IP protocol are received. In addition a RAW socket can be bound to a specific network device using SO_BINDTODEVICE; see socket(7).

You cannot bind a raw socket to a specific port because "port" is a concept in TCP and UDP, not IP. With a sneek at the header diagrams for those three protocols and it should become obvious: i am working at a lower level, where the concept of port is not known. This is what i understand regarding port numbers.

Ports are constructs of TCP and UDP. Raw sockets operate at the IP layer, and IP has no concept of ports. You get the TCP and UDP headers, so you can see where the data is destined, but your raw socket can't bind to those sockets.. not without writing kernel extensions — xaxxon

Magn3s1um Magn3s1um · Accepted Answer · 2013-08-08T14:09:35

No. The mere fact that its RAW means there's no other protocol except RAW Internet Protocol. Without TCP or UDP, there won't be any port to distinguish which application this packet gets sent to, so instead, everything will have to be filtered through the IP packet's payload. You'd have to do this manually. Best way is to make a program that forwards these packets after inspection to wherever you want it to go.

How can i avoid mulitple raw socket bind to the same ip address?

1 Answers