diff options
| -rw-r--r-- | include/uapi/linux/netfilter/nf_tables.h | 21 | ||||
| -rw-r--r-- | net/netfilter/Kconfig | 9 | ||||
| -rw-r--r-- | net/netfilter/Makefile | 1 | ||||
| -rw-r--r-- | net/netfilter/nft_connlimit.c | 297 |
4 files changed, 327 insertions, 1 deletions
diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h index a089af092a29..ae00a3c49b8a 100644 --- a/include/uapi/linux/netfilter/nf_tables.h +++ b/include/uapi/linux/netfilter/nf_tables.h @@ -1043,6 +1043,24 @@ enum nft_limit_attributes { }; #define NFTA_LIMIT_MAX (__NFTA_LIMIT_MAX - 1) +enum nft_connlimit_flags { + NFT_CONNLIMIT_F_INV = (1 << 0), +}; + +/** + * enum nft_connlimit_attributes - nf_tables connlimit expression netlink attributes + * + * @NFTA_CONNLIMIT_COUNT: number of connections (NLA_U32) + * @NFTA_CONNLIMIT_FLAGS: flags (NLA_U32: enum nft_connlimit_flags) + */ +enum nft_connlimit_attributes { + NFTA_CONNLIMIT_UNSPEC, + NFTA_CONNLIMIT_COUNT, + NFTA_CONNLIMIT_FLAGS, + __NFTA_CONNLIMIT_MAX +}; +#define NFTA_CONNLIMIT_MAX (__NFTA_CONNLIMIT_MAX - 1) + /** * enum nft_counter_attributes - nf_tables counter expression netlink attributes * @@ -1357,7 +1375,8 @@ enum nft_ct_helper_attributes { #define NFT_OBJECT_QUOTA 2 #define NFT_OBJECT_CT_HELPER 3 #define NFT_OBJECT_LIMIT 4 -#define __NFT_OBJECT_MAX 5 +#define NFT_OBJECT_CONNLIMIT 5 +#define __NFT_OBJECT_MAX 6 #define NFT_OBJECT_MAX (__NFT_OBJECT_MAX - 1) /** diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig index 41240abd755f..dbd7d1fad277 100644 --- a/net/netfilter/Kconfig +++ b/net/netfilter/Kconfig @@ -517,6 +517,15 @@ config NFT_COUNTER This option adds the "counter" expression that you can use to include packet and byte counters in a rule. +config NFT_CONNLIMIT + tristate "Netfilter nf_tables connlimit module" + depends on NF_CONNTRACK + depends on NETFILTER_ADVANCED + select NETFILTER_CONNCOUNT + help + This option adds the "connlimit" expression that you can use to + ratelimit rule matchings per connections. + config NFT_LOG tristate "Netfilter nf_tables log module" help diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile index eec169555731..44449389e527 100644 --- a/net/netfilter/Makefile +++ b/net/netfilter/Makefile @@ -80,6 +80,7 @@ nf_tables-objs := nf_tables_core.o nf_tables_api.o nft_chain_filter.o \ obj-$(CONFIG_NF_TABLES) += nf_tables.o obj-$(CONFIG_NFT_COMPAT) += nft_compat.o +obj-$(CONFIG_NFT_CONNLIMIT) += nft_connlimit.o obj-$(CONFIG_NFT_NUMGEN) += nft_numgen.o obj-$(CONFIG_NFT_CT) += nft_ct.o obj-$(CONFIG_NFT_FLOW_OFFLOAD) += nft_flow_offload.o diff --git a/net/netfilter/nft_connlimit.c b/net/netfilter/nft_connlimit.c new file mode 100644 index 000000000000..50c068d660e5 --- /dev/null +++ b/net/netfilter/nft_connlimit.c @@ -0,0 +1,297 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/spinlock.h> +#include <linux/netlink.h> +#include <linux/netfilter.h> +#include <linux/netfilter/nf_tables.h> +#include <net/netfilter/nf_tables.h> +#include <net/netfilter/nf_conntrack.h> +#include <net/netfilter/nf_conntrack_count.h> +#include <net/netfilter/nf_conntrack_core.h> +#include <net/netfilter/nf_conntrack_tuple.h> +#include <net/netfilter/nf_conntrack_zones.h> + +struct nft_connlimit { + spinlock_t lock; + struct hlist_head hhead; + u32 limit; + bool invert; +}; + +static inline void nft_connlimit_do_eval(struct nft_connlimit *priv, + struct nft_regs *regs, + const struct nft_pktinfo *pkt, + const struct nft_set_ext *ext) +{ + const struct nf_conntrack_zone *zone = &nf_ct_zone_dflt; + const struct nf_conntrack_tuple *tuple_ptr; + struct nf_conntrack_tuple tuple; + enum ip_conntrack_info ctinfo; + const struct nf_conn *ct; + unsigned int count; + bool addit; + + tuple_ptr = &tuple; + + ct = nf_ct_get(pkt->skb, &ctinfo); + if (ct != NULL) { + tuple_ptr = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple; + zone = nf_ct_zone(ct); + } else if (!nf_ct_get_tuplepr(pkt->skb, skb_network_offset(pkt->skb), + nft_pf(pkt), nft_net(pkt), &tuple)) { + regs->verdict.code = NF_DROP; + return; + } + + spin_lock_bh(&priv->lock); + count = nf_conncount_lookup(nft_net(pkt), &priv->hhead, tuple_ptr, zone, + &addit); + + if (!addit) + goto out; + + if (!nf_conncount_add(&priv->hhead, tuple_ptr)) { + regs->verdict.code = NF_DROP; + spin_unlock_bh(&priv->lock); + return; + } + count++; +out: + spin_unlock_bh(&priv->lock); + + if ((count > priv->limit) ^ priv->invert) { + regs->verdict.code = NFT_BREAK; + return; + } +} + +static int nft_connlimit_do_init(const struct nft_ctx *ctx, + const struct nlattr * const tb[], + struct nft_connlimit *priv) +{ + bool invert = false; + u32 flags, limit; + + if (!tb[NFTA_CONNLIMIT_COUNT]) + return -EINVAL; + + limit = ntohl(nla_get_be32(tb[NFTA_CONNLIMIT_COUNT])); + + if (tb[NFTA_CONNLIMIT_FLAGS]) { + flags = ntohl(nla_get_be32(tb[NFTA_CONNLIMIT_FLAGS])); + if (flags & ~NFT_CONNLIMIT_F_INV) + return -EOPNOTSUPP; + if (flags & NFT_CONNLIMIT_F_INV) + invert = true; + } + + spin_lock_init(&priv->lock); + INIT_HLIST_HEAD(&priv->hhead); + priv->limit = limit; + priv->invert = invert; + + return nf_ct_netns_get(ctx->net, ctx->family); +} + +static void nft_connlimit_do_destroy(const struct nft_ctx *ctx, + struct nft_connlimit *priv) +{ + nf_ct_netns_put(ctx->net, ctx->family); + nf_conncount_cache_free(&priv->hhead); +} + +static int nft_connlimit_do_dump(struct sk_buff *skb, + struct nft_connlimit *priv) +{ + if (nla_put_be32(skb, NFTA_CONNLIMIT_COUNT, htonl(priv->limit))) + goto nla_put_failure; + if (priv->invert && + nla_put_be32(skb, NFTA_CONNLIMIT_FLAGS, htonl(NFT_CONNLIMIT_F_INV))) + goto nla_put_failure; + + return 0; + +nla_put_failure: + return -1; +} + +static inline void nft_connlimit_obj_eval(struct nft_object *obj, + struct nft_regs *regs, + const struct nft_pktinfo *pkt) +{ + struct nft_connlimit *priv = nft_obj_data(obj); + + nft_connlimit_do_eval(priv, regs, pkt, NULL); +} + +static int nft_connlimit_obj_init(const struct nft_ctx *ctx, + const struct nlattr * const tb[], + struct nft_object *obj) +{ + struct nft_connlimit *priv = nft_obj_data(obj); + + return nft_connlimit_do_init(ctx, tb, priv); +} + +static void nft_connlimit_obj_destroy(const struct nft_ctx *ctx, + struct nft_object *obj) +{ + struct nft_connlimit *priv = nft_obj_data(obj); + + nft_connlimit_do_destroy(ctx, priv); +} + +static int nft_connlimit_obj_dump(struct sk_buff *skb, + struct nft_object *obj, bool reset) +{ + struct nft_connlimit *priv = nft_obj_data(obj); + + return nft_connlimit_do_dump(skb, priv); +} + +static const struct nla_policy nft_connlimit_policy[NFTA_CONNLIMIT_MAX + 1] = { + [NFTA_CONNLIMIT_COUNT] = { .type = NLA_U32 }, + [NFTA_CONNLIMIT_FLAGS] = { .type = NLA_U32 }, +}; + +static struct nft_object_type nft_connlimit_obj_type; +static const struct nft_object_ops nft_connlimit_obj_ops = { + .type = &nft_connlimit_obj_type, + .size = sizeof(struct nft_connlimit), + .eval = nft_connlimit_obj_eval, + .init = nft_connlimit_obj_init, + .destroy = nft_connlimit_obj_destroy, + .dump = nft_connlimit_obj_dump, +}; + +static struct nft_object_type nft_connlimit_obj_type __read_mostly = { + .type = NFT_OBJECT_CONNLIMIT, + .ops = &nft_connlimit_obj_ops, + .maxattr = NFTA_CONNLIMIT_MAX, + .policy = nft_connlimit_policy, + .owner = THIS_MODULE, +}; + +static void nft_connlimit_eval(const struct nft_expr *expr, + struct nft_regs *regs, + const struct nft_pktinfo *pkt) +{ + struct nft_connlimit *priv = nft_expr_priv(expr); + + nft_connlimit_do_eval(priv, regs, pkt, NULL); +} + +static int nft_connlimit_dump(struct sk_buff *skb, const struct nft_expr *expr) +{ + struct nft_connlimit *priv = nft_expr_priv(expr); + + return nft_connlimit_do_dump(skb, priv); +} + +static int nft_connlimit_init(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nlattr * const tb[]) +{ + struct nft_connlimit *priv = nft_expr_priv(expr); + + return nft_connlimit_do_init(ctx, tb, priv); +} + +static void nft_connlimit_destroy(const struct nft_ctx *ctx, + const struct nft_expr *expr) +{ + struct nft_connlimit *priv = nft_expr_priv(expr); + + nft_connlimit_do_destroy(ctx, priv); +} + +static int nft_connlimit_clone(struct nft_expr *dst, const struct nft_expr *src) +{ + struct nft_connlimit *priv_dst = nft_expr_priv(dst); + struct nft_connlimit *priv_src = nft_expr_priv(src); + + spin_lock_init(&priv_dst->lock); + INIT_HLIST_HEAD(&priv_dst->hhead); + priv_dst->limit = priv_src->limit; + priv_dst->invert = priv_src->invert; + + return 0; +} + +static void nft_connlimit_destroy_clone(const struct nft_ctx *ctx, + const struct nft_expr *expr) +{ + struct nft_connlimit *priv = nft_expr_priv(expr); + + nf_conncount_cache_free(&priv->hhead); +} + +static bool nft_connlimit_gc(struct net *net, const struct nft_expr *expr) +{ + struct nft_connlimit *priv = nft_expr_priv(expr); + bool addit, ret; + + spin_lock_bh(&priv->lock); + nf_conncount_lookup(net, &priv->hhead, NULL, &nf_ct_zone_dflt, &addit); + + ret = hlist_empty(&priv->hhead); + spin_unlock_bh(&priv->lock); + + return ret; +} + +static struct nft_expr_type nft_connlimit_type; +static const struct nft_expr_ops nft_connlimit_ops = { + .type = &nft_connlimit_type, + .size = NFT_EXPR_SIZE(sizeof(struct nft_connlimit)), + .eval = nft_connlimit_eval, + .init = nft_connlimit_init, + .destroy = nft_connlimit_destroy, + .clone = nft_connlimit_clone, + .destroy_clone = nft_connlimit_destroy_clone, + .dump = nft_connlimit_dump, + .gc = nft_connlimit_gc, +}; + +static struct nft_expr_type nft_connlimit_type __read_mostly = { + .name = "connlimit", + .ops = &nft_connlimit_ops, + .policy = nft_connlimit_policy, + .maxattr = NFTA_CONNLIMIT_MAX, + .flags = NFT_EXPR_STATEFUL | NFT_EXPR_GC, + .owner = THIS_MODULE, +}; + +static int __init nft_connlimit_module_init(void) +{ + int err; + + err = nft_register_obj(&nft_connlimit_obj_type); + if (err < 0) + return err; + + err = nft_register_expr(&nft_connlimit_type); + if (err < 0) + goto err1; + + return 0; +err1: + nft_unregister_obj(&nft_connlimit_obj_type); + return err; +} + +static void __exit nft_connlimit_module_exit(void) +{ + nft_unregister_expr(&nft_connlimit_type); + nft_unregister_obj(&nft_connlimit_obj_type); +} + +module_init(nft_connlimit_module_init); +module_exit(nft_connlimit_module_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Pablo Neira Ayuso"); +MODULE_ALIAS_NFT_EXPR("connlimit"); +MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_CONNLIMIT); |