Thanks for the help.
I decided to use the netlink socket to receive message
that the firewall (iptables) have queued for the user.
But i still have the problem that i can read anything
from the netlink socket i've opened.
Following configuration was performed:
- I have loaded the modules ip_queue.o,
iptable_filter.o and ip_tables.o.
- iptables -I INPUT 1 -p icmp -j QUEUE ( At the
command line, for queueing all incoming ICMP packet).
A sample code:
int main(int argc, char** argv)
{
int sockfd;
unsigned char *buffer;
struct cmsghdr cmsg;
struct iovec iov;
struct sockaddr_nl nladdr={
nl_family:AF_NETLINK
};
struct msghdr msg = {
(void *)&nladdr, sizeof(nladdr),
&iov, 1, NULL, 1024, 0};
if ((sockfd = socket(PF_NETLINK,
SOCK_DGRAM,NETLINK_FIREWALL)) < 0) {
perror("netlink socket");
return -1;
}
if (recvmsg(sockfd, &msg, 0) < 0) {
perror("recvmsg");
return -1;
}
close(sockfd);
return 0;
}
I receive nothing in the netlink socket. Why ?
Best Regards.
--- Andi Kleen <ak@suse.de> schrieb: > On Wed, Apr 11,
2001 at 12:27:01PM -0400, Jason Lunz
> wrote:
> > ak@suse.de said:
> > >It's not possible using raw sockets, but you can
> do it via appropiate
> > >netfilter rules and the netfilter user queue
> target. Then all packets
> > >not reinjected by the user queue daemon will get
> lost. This is a 2.4
> > >solution.
> >
> > True, but netfilter is IP-only AFAIK. I've hacked
> in a way to do this
> > for *all* protocols, but as far as I can tell, you
> can't do it without
> > dropping the skb before handing it off to the
> registered packet_types in
> > net_rx_action().
>
> If you don't need receiving on the local box you
> could also do it via
> ethertap device or packet socket on dummy device,
> and then reinject into the
> network. It'll not work for local packets though,
> because the routing
> code does not allow to route locally destined
> packets somewhere else.
>
>
> -Andi
> -
> : send the line
> "unsubscribe linux-net" in
> the body of a message to majordomo@vger.kernel.org
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