From 7e0b2b57f01d183e1c84114f1f2287737358d748 Mon Sep 17 00:00:00 2001 From: Harsha Sharma Date: Tue, 7 Aug 2018 17:14:23 +0200 Subject: [PATCH] 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 %./libnftnl/examples/nft-ct-timeout-del ip raw cttime Joint work with Pablo Neira. Signed-off-by: Harsha Sharma Signed-off-by: Pablo Neira Ayuso --- include/uapi/linux/netfilter/nf_tables.h | 14 ++- net/netfilter/nft_ct.c | 204 ++++++++++++++++++++++++++++++- 2 files changed, 216 insertions(+), 2 deletions(-) diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h index 94657c7..e23290f 100644 --- a/include/uapi/linux/netfilter/nf_tables.h +++ b/include/uapi/linux/netfilter/nf_tables.h @@ -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) /** diff --git a/net/netfilter/nft_ct.c b/net/netfilter/nft_ct.c index 3bc82ee..4788458 100644 --- a/net/netfilter/nft_ct.c +++ b/net/netfilter/nft_ct.c @@ -22,6 +22,8 @@ #include #include #include +#include +#include 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 "); 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); -- 2.7.4