diff options
Diffstat (limited to 'net/netfilter/nft_connlimit.c')
-rw-r--r-- | net/netfilter/nft_connlimit.c | 303 |
1 files changed, 303 insertions, 0 deletions
diff --git a/net/netfilter/nft_connlimit.c b/net/netfilter/nft_connlimit.c new file mode 100644 index 000000000..d657f999a --- /dev/null +++ b/net/netfilter/nft_connlimit.c @@ -0,0 +1,303 @@ +/* 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 { + struct nf_conncount_list *list; + 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; + + 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; + } + + if (nf_conncount_add(nft_net(pkt), priv->list, tuple_ptr, zone)) { + regs->verdict.code = NF_DROP; + return; + } + + count = priv->list->count; + + 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; + int err; + + 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; + } + + priv->list = kmalloc(sizeof(*priv->list), GFP_KERNEL_ACCOUNT); + if (!priv->list) + return -ENOMEM; + + nf_conncount_list_init(priv->list); + priv->limit = limit; + priv->invert = invert; + + err = nf_ct_netns_get(ctx->net, ctx->family); + if (err < 0) + goto err_netns; + + return 0; +err_netns: + kfree(priv->list); + + return err; +} + +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->list); + kfree(priv->list); +} + +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); + + priv_dst->list = kmalloc(sizeof(*priv_dst->list), GFP_ATOMIC); + if (!priv_dst->list) + return -ENOMEM; + + nf_conncount_list_init(priv_dst->list); + 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->list); + kfree(priv->list); +} + +static bool nft_connlimit_gc(struct net *net, const struct nft_expr *expr) +{ + struct nft_connlimit *priv = nft_expr_priv(expr); + bool ret; + + local_bh_disable(); + ret = nf_conncount_gc_list(net, priv->list); + local_bh_enable(); + + 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, + .reduce = NFT_REDUCE_READONLY, +}; + +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); +MODULE_DESCRIPTION("nftables connlimit rule support"); |