Commit 7e0b2b57 authored by Harsha Sharma's avatar Harsha Sharma Committed by Pablo Neira Ayuso
Browse files

netfilter: nft_ct: add ct timeout support 



This patch allows to add, list and delete connection tracking timeout
policies via nft objref infrastructure and assigning these timeout
via nft rule.

%./libnftnl/examples/nft-ct-timeout-add ip raw cttime tcp

Ruleset:

table ip raw {
   ct timeout cttime {
       protocol tcp;
       policy = {established: 111, close: 13 }
   }

   chain output {
       type filter hook output priority -300; policy accept;
       ct timeout set "cttime"
   }
}

%./libnftnl/examples/nft-rule-ct-timeout-add ip raw output cttime

%conntrack -E
[NEW] tcp      6 111 ESTABLISHED src=172.16.19.128 dst=172.16.19.1
sport=22 dport=41360 [UNREPLIED] src=172.16.19.1 dst=172.16.19.128
sport=41360 dport=22

%nft delete rule ip raw output handle <handle>
%./libnftnl/examples/nft-ct-timeout-del ip raw cttime

Joint work with Pablo Neira.

Signed-off-by: default avatarHarsha Sharma <harshasharmaiitr@gmail.com>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent ad83f2a9

include/uapi/linux/netfilter/nf_tables.h

+13 −1
Original line number Diff line number Diff line
@@ -958,6 +958,7 @@ enum nft_socket_keys { 
 * @NFT_CT_DST_IP: conntrack layer 3 protocol destination (IPv4 address)

 * @NFT_CT_SRC_IP6: conntrack layer 3 protocol source (IPv6 address)

 * @NFT_CT_DST_IP6: conntrack layer 3 protocol destination (IPv6 address)

 * @NFT_CT_TIMEOUT: connection tracking timeout policy assigned to conntrack

 */

enum nft_ct_keys {

	NFT_CT_STATE,
@@ -983,6 +984,7 @@ enum nft_ct_keys { 
	NFT_CT_DST_IP,

	NFT_CT_SRC_IP6,

	NFT_CT_DST_IP6,

	NFT_CT_TIMEOUT,

	__NFT_CT_MAX

};

#define NFT_CT_MAX		(__NFT_CT_MAX - 1)
@@ -1411,6 +1413,15 @@ enum nft_ct_helper_attributes { 
};

#define NFTA_CT_HELPER_MAX	(__NFTA_CT_HELPER_MAX - 1)



enum nft_ct_timeout_timeout_attributes {

	NFTA_CT_TIMEOUT_UNSPEC,

	NFTA_CT_TIMEOUT_L3PROTO,

	NFTA_CT_TIMEOUT_L4PROTO,

	NFTA_CT_TIMEOUT_DATA,

	__NFTA_CT_TIMEOUT_MAX,

};

#define NFTA_CT_TIMEOUT_MAX	(__NFTA_CT_TIMEOUT_MAX - 1)



#define NFT_OBJECT_UNSPEC	0

#define NFT_OBJECT_COUNTER	1

#define NFT_OBJECT_QUOTA	2
@@ -1418,7 +1429,8 @@ enum nft_ct_helper_attributes { 
#define NFT_OBJECT_LIMIT	4

#define NFT_OBJECT_CONNLIMIT	5

#define NFT_OBJECT_TUNNEL	6

#define __NFT_OBJECT_MAX	7

#define NFT_OBJECT_CT_TIMEOUT	7

#define __NFT_OBJECT_MAX	8

#define NFT_OBJECT_MAX		(__NFT_OBJECT_MAX - 1)



/**

net/netfilter/nft_ct.c

+203 −1
Original line number Diff line number Diff line
@@ -22,6 +22,8 @@ 
#include <net/netfilter/nf_conntrack_helper.h>

#include <net/netfilter/nf_conntrack_ecache.h>

#include <net/netfilter/nf_conntrack_labels.h>

#include <net/netfilter/nf_conntrack_timeout.h>

#include <net/netfilter/nf_conntrack_l4proto.h>



struct nft_ct {

	enum nft_ct_keys	key:8;
@@ -765,6 +767,194 @@ static struct nft_expr_type nft_notrack_type __read_mostly = { 
	.owner		= THIS_MODULE,

};



#ifdef CONFIG_NF_CONNTRACK_TIMEOUT

static int

nft_ct_timeout_parse_policy(void *timeouts,

			    const struct nf_conntrack_l4proto *l4proto,

			    struct net *net, const struct nlattr *attr)

{

	struct nlattr **tb;

	int ret = 0;



	if (!l4proto->ctnl_timeout.nlattr_to_obj)

		return 0;



	tb = kcalloc(l4proto->ctnl_timeout.nlattr_max + 1, sizeof(*tb),

		     GFP_KERNEL);



	if (!tb)

		return -ENOMEM;



	ret = nla_parse_nested(tb, l4proto->ctnl_timeout.nlattr_max,

			       attr, l4proto->ctnl_timeout.nla_policy,

			       NULL);

	if (ret < 0)

		goto err;



	ret = l4proto->ctnl_timeout.nlattr_to_obj(tb, net, timeouts);



err:

	kfree(tb);

	return ret;

}



struct nft_ct_timeout_obj {

	struct nf_conn		*tmpl;

	u8			l4proto;

};



static void nft_ct_timeout_obj_eval(struct nft_object *obj,

				    struct nft_regs *regs,

				    const struct nft_pktinfo *pkt)

{

	const struct nft_ct_timeout_obj *priv = nft_obj_data(obj);

	struct nf_conn *ct = (struct nf_conn *)skb_nfct(pkt->skb);

	struct sk_buff *skb = pkt->skb;



	if (ct ||

	    priv->l4proto != pkt->tprot)

		return;



	nf_ct_set(skb, priv->tmpl, IP_CT_NEW);

}



static int nft_ct_timeout_obj_init(const struct nft_ctx *ctx,

				   const struct nlattr * const tb[],

				   struct nft_object *obj)

{

	const struct nf_conntrack_zone *zone = &nf_ct_zone_dflt;

	struct nft_ct_timeout_obj *priv = nft_obj_data(obj);

	const struct nf_conntrack_l4proto *l4proto;

	struct nf_conn_timeout *timeout_ext;

	struct nf_ct_timeout *timeout;

	int l3num = ctx->family;

	struct nf_conn *tmpl;

	__u8 l4num;

	int ret;



	if (!tb[NFTA_CT_TIMEOUT_L3PROTO] ||

	    !tb[NFTA_CT_TIMEOUT_L4PROTO] ||

	    !tb[NFTA_CT_TIMEOUT_DATA])

		return -EINVAL;



	l3num = ntohs(nla_get_be16(tb[NFTA_CT_TIMEOUT_L3PROTO]));

	l4num = nla_get_u8(tb[NFTA_CT_TIMEOUT_L4PROTO]);

	priv->l4proto = l4num;



	l4proto = nf_ct_l4proto_find_get(l3num, l4num);



	if (l4proto->l4proto != l4num) {

		ret = -EOPNOTSUPP;

		goto err_proto_put;

	}



	timeout = kzalloc(sizeof(struct nf_ct_timeout) +

			  l4proto->ctnl_timeout.obj_size, GFP_KERNEL);

	if (timeout == NULL) {

		ret = -ENOMEM;

		goto err_proto_put;

	}



	ret = nft_ct_timeout_parse_policy(&timeout->data, l4proto, ctx->net,

					  tb[NFTA_CT_TIMEOUT_DATA]);

	if (ret < 0)

		goto err_free_timeout;



	timeout->l3num = l3num;

	timeout->l4proto = l4proto;

	tmpl = nf_ct_tmpl_alloc(ctx->net, zone, GFP_ATOMIC);

	if (!tmpl) {

		ret = -ENOMEM;

		goto err_free_timeout;

	}



	timeout_ext = nf_ct_timeout_ext_add(tmpl, timeout, GFP_ATOMIC);

	if (!timeout_ext) {

		ret = -ENOMEM;

		goto err_free_tmpl;

	}



	ret = nf_ct_netns_get(ctx->net, ctx->family);

	if (ret < 0)

		goto err_free_tmpl;



	priv->tmpl = tmpl;



	return 0;



err_free_tmpl:

	nf_ct_tmpl_free(tmpl);

err_free_timeout:

	kfree(timeout);

err_proto_put:

	nf_ct_l4proto_put(l4proto);

	return ret;

}



static void nft_ct_timeout_obj_destroy(const struct nft_ctx *ctx,

				       struct nft_object *obj)

{

	struct nft_ct_timeout_obj *priv = nft_obj_data(obj);

	struct nf_conn_timeout *t = nf_ct_timeout_find(priv->tmpl);

	struct nf_ct_timeout *timeout;



	timeout = rcu_dereference_raw(t->timeout);

	nf_ct_untimeout(ctx->net, timeout);

	nf_ct_l4proto_put(timeout->l4proto);

	nf_ct_netns_put(ctx->net, ctx->family);

	nf_ct_tmpl_free(priv->tmpl);

}



static int nft_ct_timeout_obj_dump(struct sk_buff *skb,

				   struct nft_object *obj, bool reset)

{

	const struct nft_ct_timeout_obj *priv = nft_obj_data(obj);

	const struct nf_conn_timeout *t = nf_ct_timeout_find(priv->tmpl);

	const struct nf_ct_timeout *timeout = rcu_dereference_raw(t->timeout);

	struct nlattr *nest_params;

	int ret;



	if (nla_put_u8(skb, NFTA_CT_TIMEOUT_L4PROTO, timeout->l4proto->l4proto) ||

	    nla_put_be16(skb, NFTA_CT_TIMEOUT_L3PROTO, htons(timeout->l3num)))

		return -1;



	nest_params = nla_nest_start(skb, NFTA_CT_TIMEOUT_DATA | NLA_F_NESTED);

	if (!nest_params)

		return -1;



	ret = timeout->l4proto->ctnl_timeout.obj_to_nlattr(skb, &timeout->data);

	if (ret < 0)

		return -1;

	nla_nest_end(skb, nest_params);

	return 0;

}



static const struct nla_policy nft_ct_timeout_policy[NFTA_CT_TIMEOUT_MAX + 1] = {

	[NFTA_CT_TIMEOUT_L3PROTO] = {.type = NLA_U16 },

	[NFTA_CT_TIMEOUT_L4PROTO] = {.type = NLA_U8 },

	[NFTA_CT_TIMEOUT_DATA]	  = {.type = NLA_NESTED },

};



static struct nft_object_type nft_ct_timeout_obj_type;



static const struct nft_object_ops nft_ct_timeout_obj_ops = {

	.type		= &nft_ct_timeout_obj_type,

	.size		= sizeof(struct nft_ct_timeout_obj),

	.eval		= nft_ct_timeout_obj_eval,

	.init		= nft_ct_timeout_obj_init,

	.destroy	= nft_ct_timeout_obj_destroy,

	.dump		= nft_ct_timeout_obj_dump,

};



static struct nft_object_type nft_ct_timeout_obj_type __read_mostly = {

	.type		= NFT_OBJECT_CT_TIMEOUT,

	.ops		= &nft_ct_timeout_obj_ops,

	.maxattr	= NFTA_CT_TIMEOUT_MAX,

	.policy		= nft_ct_timeout_policy,

	.owner		= THIS_MODULE,

};

#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */



static int nft_ct_helper_obj_init(const struct nft_ctx *ctx,

				  const struct nlattr * const tb[],

				  struct nft_object *obj)
@@ -949,9 +1139,17 @@ static int __init nft_ct_module_init(void) 
	err = nft_register_obj(&nft_ct_helper_obj_type);

	if (err < 0)

		goto err2;



#ifdef CONFIG_NF_CONNTRACK_TIMEOUT

	err = nft_register_obj(&nft_ct_timeout_obj_type);

	if (err < 0)

		goto err3;

#endif

	return 0;



#ifdef CONFIG_NF_CONNTRACK_TIMEOUT

err3:

	nft_unregister_obj(&nft_ct_helper_obj_type);

#endif

err2:

	nft_unregister_expr(&nft_notrack_type);

err1:
@@ -961,6 +1159,9 @@ err1: 


static void __exit nft_ct_module_exit(void)

{

#ifdef CONFIG_NF_CONNTRACK_TIMEOUT

	nft_unregister_obj(&nft_ct_timeout_obj_type);

#endif

	nft_unregister_obj(&nft_ct_helper_obj_type);

	nft_unregister_expr(&nft_notrack_type);

	nft_unregister_expr(&nft_ct_type);
@@ -974,3 +1175,4 @@ MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); 
MODULE_ALIAS_NFT_EXPR("ct");

MODULE_ALIAS_NFT_EXPR("notrack");

MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_CT_HELPER);

MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_CT_TIMEOUT);

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