Hi Harsha,
Comments below.
On Mon, May 28, 2018 at 11:58:11PM +0200, Harsha Sharma wrote:
> 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"
> }
> }
>
> Signed-off-by: Harsha Sharma <harshasharmai...@gmail.com>
> ---
> 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 | 16 ++-
> net/netfilter/nft_ct.c | 196
> ++++++++++++++++++++++++++-
> 3 files changed, 210 insertions(+), 3 deletions(-)
>
> diff --git a/include/net/netfilter/nf_conntrack_timeout.h
> b/include/net/netfilter/nf_conntrack_timeout.h
> index 9468ab4ad12d..ae0f59cc1ffa 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 66dceee0ae30..3915f898607b 100644
> --- a/include/uapi/linux/netfilter/nf_tables.h
> +++ b/include/uapi/linux/netfilter/nf_tables.h
> @@ -920,6 +920,7 @@ enum nft_rt_attributes {
> * @NFT_CT_AVGPKT: conntrack average bytes per packet
> * @NFT_CT_ZONE: conntrack zone
> * @NFT_CT_EVENTMASK: ctnetlink events to be generated for this conntrack
> + * @NFT_CT_TIMEOUT: connection tracking timeout policy assigned to conntrack
> */
> enum nft_ct_keys {
> NFT_CT_STATE,
> @@ -941,6 +942,7 @@ enum nft_ct_keys {
> NFT_CT_AVGPKT,
> NFT_CT_ZONE,
> NFT_CT_EVENTMASK,
> + NFT_CT_TIMEOUT,
> };
>
> /**
> @@ -1302,12 +1304,24 @@ 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_USE,
This NFTA_CT_TIMEOUT_USE is not used, remove it.
> + NFTA_CT_TIMEOUT_EXPR,
Same thing with this attribute.
> + __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_MAX 5
> +#define NFT_OBJECT_CT_TIMEOUT 5
> +#define __NFT_OBJECT_MAX 6
> #define NFT_OBJECT_MAX (__NFT_OBJECT_MAX - 1)
>
> /**
> diff --git a/net/netfilter/nft_ct.c b/net/netfilter/nft_ct.c
> index 6ab274b14484..2d1a2127a00b 100644
> --- a/net/netfilter/nft_ct.c
> +++ b/net/netfilter/nft_ct.c
[...]
> @@ -727,6 +733,163 @@ static struct nft_expr_type nft_notrack_type
> __read_mostly = {
> .owner = THIS_MODULE,
> };
>
> +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 nf_conn *ct;
> + struct ctnl_timeout *to_assign = NULL;
> + struct nf_conn_timeout *timeout_ext;
> + struct nf_conntrack_zone zone;
> +
> + memset(&zone, 0, sizeof(zone));
Please, use:
const struct nf_conntrack_zone *zone = &nf_ct_zone_dflt;
instead to initialize the zone.
> +
> + ct = nf_ct_tmpl_alloc(nft_net(pkt), &zone, GFP_KERNEL);
Allocate template from the _init() path, then store reference to it
via:
priv->tmpl.
And from _eval() path, attach it to the skbuff.
See:
https://elixir.bootlin.com/linux/latest/source/net/netfilter/nf_conntrack_core.c#L1200
The idea is to offer a template conntrack containing the timeout
policy via skbuff, that nf_conntrack_in() will take to refresh the
timeout.
You have to do this from the raw table, ie. in nft, create a filter
chain using priority -300, to test this.
> +
> + if (!ct ||
> + nf_ct_is_confirmed(ct)) {
> + return;
> + }
> +
> + to_assign = priv->timeout;
> +
> + timeout_ext = nf_ct_timeout_ext_add(ct, priv->timeout, GFP_ATOMIC);
> +
> + if (timeout_ext) {
> + rcu_assign_pointer(timeout_ext->timeout, to_assign);
> + atomic_inc(&ct->ct_general.use);
> + }
> +}
> +
> +static int nft_ct_timeout_obj_init(const struct nft_ctx *ctx,
> + const struct nlattr * const tb[],
> + struct nft_object *obj)
> +{
> + __u16 l3num;
> + __u8 l4num;
> + struct nft_ct_timeout_obj *priv = nft_obj_data(obj);
> + const struct nf_conntrack_l4proto *l4proto;
> + struct ctnl_timeout *timeout, *matching = NULL;
> + int ret;
> +
> + if (!tb[NFTA_CT_TIMEOUT_L4PROTO] ||
> + !tb[NFTA_CT_TIMEOUT_L3PROTO] ||
> + !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]);
> +
> + 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;
> +
> + return 0;
> +err:
> + kfree(timeout);
> +err_proto_put:
> + nf_ct_l4proto_put(l4proto);
> + return ret;
> +}
> +
> +static void nft_ct_timeout_obj_destroy(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);
> + }
> +}
> +
> +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;
> +}
> +
> static int nft_ct_helper_obj_init(const struct nft_ctx *ctx,
> const struct nlattr * const tb[],
> struct nft_object *obj)
> @@ -889,6 +1052,30 @@ 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,
^
missing tab here.
> + .owner = THIS_MODULE,
> +};
> +
> static int __init nft_ct_module_init(void)
> {
> int err;
> @@ -904,6 +1091,9 @@ static int __init nft_ct_module_init(void)
> goto err1;
>
> err = nft_register_obj(&nft_ct_helper_obj_type);
> + if (err < 0)
> + goto err2;
You probably need:
goto err3;
to unwind the error.
> + err = nft_register_obj(&nft_ct_timeout_obj_type);
> if (err < 0)
> goto err2;
>
> @@ -919,6 +1109,7 @@ 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);
> }
> @@ -931,3 +1122,4 @@ 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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