Re: netfilter_queue reinjecting packets

[Patrick McHardy <kaber@trash.net>]

aton wrote:
> has anyone used netfilter_queue and successfully re-injected packets into the net?
> 
> i want to write sort of a userspace routing application. 
> 
> host A is my workstation, it has host B as default gateway.
> 
> on host B my routing application runs. 
> it receives packets from netfilter_queue using libnetfilter_queue.
> this works very well and i can display the whole packets.
> 
> now i just want to send them back into the net, so that they reach their destination.
> 
> i modified the main loop in the source of nfqnl_test.c in the libnetfilter_queue package:
> 
> 	while ((rv=recv(fd, buf, sizeof(buf), 0)) >= 0)
> 	{
> 		printf("pkt received:\n");
> 		
> 		printf("sending packet back\n");
> 		
> 		if ((sv=send(fd, buf, sizeof(buf), 0))==-1)
> 		{
> 			perror("send");
> 			exit(EXIT_FAILURE);
> 		}
> 		printf("done\n");
> 	}
> 
> this should send every packet back to... where? 
> it seems the packets are just sent into nirvana, i cannot sniff them, and i dont get an error from send().

nfnql_test already reinjects packets by the call to nfq_issue_verdict.
It seems you need to read the documentation ..