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

Ruleset:

table ip raw {
   ct timeout cttime {
       protocol tcp
       established 111 close 13
       l3proto ip
   }

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

%./libnftnl/examples/nft-ct-timeout-add ip raw cttime tcp
%./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 zone=4

Signed-off-by: Harsha Sharma <harshasharmai...@gmail.com>
---
Changes in v5:
 - wrap with NF_CT_NETLINK_TIMEOUT option
 - attach timeout template in init
 - other minor changes
Changes in v4:
 - Remove unused attributes
 - allocate template from init() path
 - minor changes
 - updated log message
 - pull to latest tree
Changes in v3:
 - Use nf_ct_tmpl_alloc to attach timeout via template conntrack.
Changes in v2:
 - Add code for nft_ct_timeout_obj_eval
 - remove likely() from code
 - remove vla in ctnl_timeout_parse_policy

 include/net/netfilter/nf_conntrack_timeout.h |   1 +
 include/uapi/linux/netfilter/nf_tables.h     |  14 +-
 net/netfilter/nft_ct.c                       | 203 ++++++++++++++++++++++++++-
 3 files changed, 215 insertions(+), 3 deletions(-)

diff --git a/include/net/netfilter/nf_conntrack_timeout.h 
b/include/net/netfilter/nf_conntrack_timeout.h
index 80ceb3d0291d..c3b81a82b3c9 100644
--- a/include/net/netfilter/nf_conntrack_timeout.h
+++ b/include/net/netfilter/nf_conntrack_timeout.h
@@ -8,6 +8,7 @@
 #include <linux/refcount.h>
 #include <net/netfilter/nf_conntrack.h>
 #include <net/netfilter/nf_conntrack_extend.h>
+#include <net/netfilter/nf_conntrack_l4proto.h>
 
 #define CTNL_TIMEOUT_NAME_MAX  32
 
diff --git a/include/uapi/linux/netfilter/nf_tables.h 
b/include/uapi/linux/netfilter/nf_tables.h
index 89438e68dc03..552fa5a6b7c3 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -955,6 +955,7 @@ 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,
@@ -980,6 +981,7 @@ 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)
@@ -1392,13 +1394,23 @@ 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
 #define NFT_OBJECT_CT_HELPER   3
 #define NFT_OBJECT_LIMIT       4
 #define NFT_OBJECT_CONNLIMIT   5
-#define __NFT_OBJECT_MAX       6
+#define NFT_OBJECT_CT_TIMEOUT  6
+#define __NFT_OBJECT_MAX       7
 #define NFT_OBJECT_MAX         (__NFT_OBJECT_MAX - 1)
 
 /**
diff --git a/net/netfilter/nft_ct.c b/net/netfilter/nft_ct.c
index 1435ffc5f57e..40678a2e65a4 100644
--- a/net/netfilter/nft_ct.c
+++ b/net/netfilter/nft_ct.c
@@ -22,6 +22,9 @@
 #include <net/netfilter/nf_conntrack_helper.h>
 #include <net/netfilter/nf_conntrack_ecache.h>
 #include <net/netfilter/nf_conntrack_labels.h>
+#include <linux/netfilter/nfnetlink_cttimeout.h>
+#include <net/netfilter/nf_conntrack_timeout.h>
+#include <net/netfilter/nf_conntrack_l4proto.h>
 
 struct nft_ct {
        enum nft_ct_keys        key:8;
@@ -32,12 +35,18 @@ struct nft_ct {
        };
 };
 
-struct nft_ct_helper_obj  {
+struct nft_ct_helper_obj {
        struct nf_conntrack_helper *helper4;
        struct nf_conntrack_helper *helper6;
        u8 l4proto;
 };
 
+struct nft_ct_timeout_obj {
+       struct ctnl_timeout *timeout;
+       struct nf_conn *tmpl;
+       struct nf_conn_timeout *ext;
+};
+
 #ifdef CONFIG_NF_CONNTRACK_ZONES
 static DEFINE_PER_CPU(struct nf_conn *, nft_ct_pcpu_template);
 static unsigned int nft_ct_pcpu_template_refcnt __read_mostly;
@@ -412,7 +421,6 @@ static int nft_ct_get_init(const struct nft_ctx *ctx,
                        return -EINVAL;
                len = NF_CT_HELPER_NAME_LEN;
                break;
-
        case NFT_CT_L3PROTOCOL:
        case NFT_CT_PROTOCOL:
                /* For compatibility, do not report error if NFTA_CT_DIRECTION
@@ -765,6 +773,168 @@ static struct nft_expr_type nft_notrack_type 
__read_mostly = {
        .owner          = THIS_MODULE,
 };
 
+#ifdef CONFIG_NF_CT_NETLINK_TIMEOUT
+static int
+ctnl_timeout_parse_policy(void *timeouts,
+                         const struct nf_conntrack_l4proto *l4proto,
+                         struct net *net, const struct nlattr *attr)
+{
+       int ret = 0;
+       struct nlattr **tb;
+
+       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;
+}
+
+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 ctnl_timeout *to_assign = NULL;
+       struct sk_buff *skb = pkt->skb;
+       enum ip_conntrack_info ctinfo;
+
+       if (!priv->tmpl)
+               return;
+
+       to_assign = priv->timeout;
+
+       if (!nf_ct_get(skb, &ctinfo))
+               nf_ct_set(skb, priv->tmpl, IP_CT_NEW);
+
+       if (priv->ext)
+               rcu_assign_pointer(priv->ext->timeout, to_assign);
+}
+
+static int nft_ct_timeout_obj_init(const struct nft_ctx *ctx,
+                                  const struct nlattr * const tb[],
+                                  struct nft_object *obj)
+{
+       __u8 l4num;
+       struct nft_ct_timeout_obj *priv = nft_obj_data(obj);
+       const struct nf_conntrack_l4proto *l4proto;
+       struct ctnl_timeout *timeout, *matching = NULL;
+       struct nf_conn *tmpl;
+       const struct nf_conntrack_zone *zone = &nf_ct_zone_dflt;
+       int ret;
+       int l3num = ctx->family;
+       struct nf_conn_timeout *timeout_ext;
+
+       if (!tb[NFTA_CT_TIMEOUT_L4PROTO] ||
+           !tb[NFTA_CT_TIMEOUT_DATA])
+               return -EINVAL;
+
+       if (tb[NFTA_CT_TIMEOUT_L3PROTO])
+               l3num = ntohs(nla_get_be16(tb[NFTA_CT_TIMEOUT_L3PROTO]));
+       l4num = nla_get_u8(tb[NFTA_CT_TIMEOUT_L4PROTO]);
+
+       INIT_LIST_HEAD(&ctx->net->nfct_timeout_list);
+       list_for_each_entry(timeout, &ctx->net->nfct_timeout_list, head) {
+               matching = timeout;
+               break;
+       }
+
+       if (matching) {
+               if (matching->l3num != l3num ||
+                   matching->l4proto->l4proto != l4num)
+                       return -EINVAL;
+               return ctnl_timeout_parse_policy(&matching->data,
+                                                matching->l4proto, ctx->net,
+                                                tb[NFTA_CT_TIMEOUT_DATA]);
+       }
+
+       l4proto = nf_ct_l4proto_find_get(l3num, l4num);
+
+       if (l4proto->l4proto != l4num) {
+               ret = -EOPNOTSUPP;
+               goto err_proto_put;
+       }
+
+       timeout = kzalloc(sizeof(struct ctnl_timeout) +
+                         l4proto->ctnl_timeout.obj_size, GFP_KERNEL);
+       if (timeout == NULL) {
+               ret = -ENOMEM;
+               goto err_proto_put;
+       }
+
+       ret = ctnl_timeout_parse_policy(&timeout->data, l4proto, ctx->net,
+                                       tb[NFTA_CT_TIMEOUT_DATA]);
+       if (ret < 0)
+               goto err;
+       timeout->l3num = l3num;
+       timeout->l4proto = l4proto;
+       list_add_tail_rcu(&timeout->head, &ctx->net->nfct_timeout_list);
+       priv->timeout = timeout;
+       tmpl = nf_ct_tmpl_alloc(ctx->net, zone, GFP_ATOMIC);
+       tmpl->zone.id = 4;
+       priv->tmpl = tmpl;
+       timeout_ext = nf_ct_timeout_ext_add(priv->tmpl, priv->timeout, 
GFP_ATOMIC);
+       priv->ext = timeout_ext;
+
+       return 0;
+
+err:
+       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);
+
+       if (refcount_dec_if_one(&priv->timeout->refcnt)) {
+               nf_ct_l4proto_put(priv->timeout->l4proto);
+               list_del_rcu(&priv->timeout->head);
+               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 ctnl_timeout *timeout = priv->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(priv->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;
+}
+#endif
+
 static int nft_ct_helper_obj_init(const struct nft_ctx *ctx,
                                  const struct nlattr * const tb[],
                                  struct nft_object *obj)
@@ -932,6 +1102,30 @@ static struct nft_object_type nft_ct_helper_obj_type 
__read_mostly = {
        .owner          = THIS_MODULE,
 };
 
+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,
+};
+
 static int __init nft_ct_module_init(void)
 {
        int err;
@@ -947,6 +1141,9 @@ static int __init nft_ct_module_init(void)
                goto err1;
 
        err = nft_register_obj(&nft_ct_helper_obj_type);
+       if (err < 0)
+               goto err2;
+       err = nft_register_obj(&nft_ct_timeout_obj_type);
        if (err < 0)
                goto err2;
 
@@ -962,6 +1159,7 @@ static int __init nft_ct_module_init(void)
 static void __exit nft_ct_module_exit(void)
 {
        nft_unregister_obj(&nft_ct_helper_obj_type);
+       nft_unregister_obj(&nft_ct_timeout_obj_type);
        nft_unregister_expr(&nft_notrack_type);
        nft_unregister_expr(&nft_ct_type);
 }
@@ -974,3 +1172,4 @@ MODULE_AUTHOR("Patrick McHardy <ka...@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);
-- 
2.14.1

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