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netfilter: nft_ct: add ct timeout support

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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: Harsha Sharma <harshasharmaiitr@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Harsha Sharma 2018-08-07 17:14:23 +02:00 committed by Pablo Neira Ayuso
parent ad83f2a9ce
commit 7e0b2b57f0
2 changed files with 216 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
include/uapi/linux/netfilter/nf_tables.h
View File

@ -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)
/**

204
net/netfilter/nft_ct.c
View File

@ -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);