netfilter: x_tables: allow to use cgroup match for LOCAL_IN nf hooks

Alexey Perevalov · ummakynes · commit a00e76349f35 · 2014-04-03T23:52:17.000+02:00
This simple modification allows iptables to work with INPUT chain in combination with cgroup module. It could be useful for counting ingress traffic per cgroup with nfacct netfilter module. There were no problems to count the egress traffic that way formerly. It's possible to get classified sk_buff after PREROUTING, due to socket lookup being done in early_demux (tcp_v4_early_demux). Also it works for udp as well. Trivial usage example, assuming we're in the same shell every step and we have enough permissions: 1) Classic net_cls cgroup initialization: mkdir /sys/fs/cgroup/net_cls mount -t cgroup -o net_cls net_cls /sys/fs/cgroup/net_cls 2) Set up cgroup for interesting application: mkdir /sys/fs/cgroup/net_cls/wget echo 1 > /sys/fs/cgroup/net_cls/wget/net_cls.classid echo $BASHPID > /sys/fs/cgroup/net_cls/wget/cgroup.procs 3) Create kernel counters: nfacct add wget-cgroup-in iptables -A INPUT -m cgroup ! --cgroup 1 -m nfacct --nfacct-name wget-cgroup-in nfacct add wget-cgroup-out iptables -A OUTPUT -m cgroup ! --cgroup 1 -m nfacct --nfacct-name wget-cgroup-out 4) Network usage: wget https://www.kernel.org/pub/linux/kernel/v3.x/testing/linux-3.14-rc6.tar.xz 5) Check results: nfacct list Cgroup approach is being used for the DataUsage (counting & blocking traffic) feature for Samsung's modification of the Tizen OS. Signed-off-by: Alexey Perevalov <a.perevalov@samsung.com> Acked-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/net/netfilter/xt_cgroup.c b/net/netfilter/xt_cgroup.c
@@ -54,7 +54,8 @@ static struct xt_match cgroup_mt_reg __read_mostly = {
 	.matchsize  = sizeof(struct xt_cgroup_info),
 	.me         = THIS_MODULE,
 	.hooks      = (1 << NF_INET_LOCAL_OUT) |
-		      (1 << NF_INET_POST_ROUTING),
+		      (1 << NF_INET_POST_ROUTING) |
+		      (1 << NF_INET_LOCAL_IN),
 };
 
 static int __init cgroup_mt_init(void)
