1 /* SPDX-License-Identifier: GPL-2.0 */
2 #include <linux/kernel.h>
3 #include <linux/init.h>
4 #include <linux/module.h>
5 #include <linux/spinlock.h>
6 #include <linux/netlink.h>
7 #include <linux/netfilter.h>
8 #include <linux/netfilter/nf_tables.h>
9 #include <net/netfilter/nf_tables.h>
10 #include <net/netfilter/nf_conntrack.h>
11 #include <net/netfilter/nf_conntrack_count.h>
12 #include <net/netfilter/nf_conntrack_core.h>
13 #include <net/netfilter/nf_conntrack_tuple.h>
14 #include <net/netfilter/nf_conntrack_zones.h>
16 struct nft_connlimit {
18 struct hlist_head hhead;
23 static inline void nft_connlimit_do_eval(struct nft_connlimit *priv,
24 struct nft_regs *regs,
25 const struct nft_pktinfo *pkt,
26 const struct nft_set_ext *ext)
28 const struct nf_conntrack_zone *zone = &nf_ct_zone_dflt;
29 const struct nf_conntrack_tuple *tuple_ptr;
30 struct nf_conntrack_tuple tuple;
31 enum ip_conntrack_info ctinfo;
32 const struct nf_conn *ct;
38 ct = nf_ct_get(pkt->skb, &ctinfo);
40 tuple_ptr = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
41 zone = nf_ct_zone(ct);
42 } else if (!nf_ct_get_tuplepr(pkt->skb, skb_network_offset(pkt->skb),
43 nft_pf(pkt), nft_net(pkt), &tuple)) {
44 regs->verdict.code = NF_DROP;
48 spin_lock_bh(&priv->lock);
49 count = nf_conncount_lookup(nft_net(pkt), &priv->hhead, tuple_ptr, zone,
55 if (!nf_conncount_add(&priv->hhead, tuple_ptr)) {
56 regs->verdict.code = NF_DROP;
57 spin_unlock_bh(&priv->lock);
62 spin_unlock_bh(&priv->lock);
64 if ((count > priv->limit) ^ priv->invert) {
65 regs->verdict.code = NFT_BREAK;
70 static int nft_connlimit_do_init(const struct nft_ctx *ctx,
71 const struct nlattr * const tb[],
72 struct nft_connlimit *priv)
77 if (!tb[NFTA_CONNLIMIT_COUNT])
80 limit = ntohl(nla_get_be32(tb[NFTA_CONNLIMIT_COUNT]));
82 if (tb[NFTA_CONNLIMIT_FLAGS]) {
83 flags = ntohl(nla_get_be32(tb[NFTA_CONNLIMIT_FLAGS]));
84 if (flags & ~NFT_CONNLIMIT_F_INV)
86 if (flags & NFT_CONNLIMIT_F_INV)
90 spin_lock_init(&priv->lock);
91 INIT_HLIST_HEAD(&priv->hhead);
93 priv->invert = invert;
95 return nf_ct_netns_get(ctx->net, ctx->family);
98 static void nft_connlimit_do_destroy(const struct nft_ctx *ctx,
99 struct nft_connlimit *priv)
101 nf_ct_netns_put(ctx->net, ctx->family);
102 nf_conncount_cache_free(&priv->hhead);
105 static int nft_connlimit_do_dump(struct sk_buff *skb,
106 struct nft_connlimit *priv)
108 if (nla_put_be32(skb, NFTA_CONNLIMIT_COUNT, htonl(priv->limit)))
109 goto nla_put_failure;
111 nla_put_be32(skb, NFTA_CONNLIMIT_FLAGS, htonl(NFT_CONNLIMIT_F_INV)))
112 goto nla_put_failure;
120 static inline void nft_connlimit_obj_eval(struct nft_object *obj,
121 struct nft_regs *regs,
122 const struct nft_pktinfo *pkt)
124 struct nft_connlimit *priv = nft_obj_data(obj);
126 nft_connlimit_do_eval(priv, regs, pkt, NULL);
129 static int nft_connlimit_obj_init(const struct nft_ctx *ctx,
130 const struct nlattr * const tb[],
131 struct nft_object *obj)
133 struct nft_connlimit *priv = nft_obj_data(obj);
135 return nft_connlimit_do_init(ctx, tb, priv);
138 static void nft_connlimit_obj_destroy(const struct nft_ctx *ctx,
139 struct nft_object *obj)
141 struct nft_connlimit *priv = nft_obj_data(obj);
143 nft_connlimit_do_destroy(ctx, priv);
146 static int nft_connlimit_obj_dump(struct sk_buff *skb,
147 struct nft_object *obj, bool reset)
149 struct nft_connlimit *priv = nft_obj_data(obj);
151 return nft_connlimit_do_dump(skb, priv);
154 static const struct nla_policy nft_connlimit_policy[NFTA_CONNLIMIT_MAX + 1] = {
155 [NFTA_CONNLIMIT_COUNT] = { .type = NLA_U32 },
156 [NFTA_CONNLIMIT_FLAGS] = { .type = NLA_U32 },
159 static struct nft_object_type nft_connlimit_obj_type;
160 static const struct nft_object_ops nft_connlimit_obj_ops = {
161 .type = &nft_connlimit_obj_type,
162 .size = sizeof(struct nft_connlimit),
163 .eval = nft_connlimit_obj_eval,
164 .init = nft_connlimit_obj_init,
165 .destroy = nft_connlimit_obj_destroy,
166 .dump = nft_connlimit_obj_dump,
169 static struct nft_object_type nft_connlimit_obj_type __read_mostly = {
170 .type = NFT_OBJECT_CONNLIMIT,
171 .ops = &nft_connlimit_obj_ops,
172 .maxattr = NFTA_CONNLIMIT_MAX,
173 .policy = nft_connlimit_policy,
174 .owner = THIS_MODULE,
177 static void nft_connlimit_eval(const struct nft_expr *expr,
178 struct nft_regs *regs,
179 const struct nft_pktinfo *pkt)
181 struct nft_connlimit *priv = nft_expr_priv(expr);
183 nft_connlimit_do_eval(priv, regs, pkt, NULL);
186 static int nft_connlimit_dump(struct sk_buff *skb, const struct nft_expr *expr)
188 struct nft_connlimit *priv = nft_expr_priv(expr);
190 return nft_connlimit_do_dump(skb, priv);
193 static int nft_connlimit_init(const struct nft_ctx *ctx,
194 const struct nft_expr *expr,
195 const struct nlattr * const tb[])
197 struct nft_connlimit *priv = nft_expr_priv(expr);
199 return nft_connlimit_do_init(ctx, tb, priv);
202 static void nft_connlimit_destroy(const struct nft_ctx *ctx,
203 const struct nft_expr *expr)
205 struct nft_connlimit *priv = nft_expr_priv(expr);
207 nft_connlimit_do_destroy(ctx, priv);
210 static int nft_connlimit_clone(struct nft_expr *dst, const struct nft_expr *src)
212 struct nft_connlimit *priv_dst = nft_expr_priv(dst);
213 struct nft_connlimit *priv_src = nft_expr_priv(src);
215 spin_lock_init(&priv_dst->lock);
216 INIT_HLIST_HEAD(&priv_dst->hhead);
217 priv_dst->limit = priv_src->limit;
218 priv_dst->invert = priv_src->invert;
223 static void nft_connlimit_destroy_clone(const struct nft_ctx *ctx,
224 const struct nft_expr *expr)
226 struct nft_connlimit *priv = nft_expr_priv(expr);
228 nf_conncount_cache_free(&priv->hhead);
231 static bool nft_connlimit_gc(struct net *net, const struct nft_expr *expr)
233 struct nft_connlimit *priv = nft_expr_priv(expr);
236 spin_lock_bh(&priv->lock);
237 nf_conncount_lookup(net, &priv->hhead, NULL, &nf_ct_zone_dflt, &addit);
239 ret = hlist_empty(&priv->hhead);
240 spin_unlock_bh(&priv->lock);
245 static struct nft_expr_type nft_connlimit_type;
246 static const struct nft_expr_ops nft_connlimit_ops = {
247 .type = &nft_connlimit_type,
248 .size = NFT_EXPR_SIZE(sizeof(struct nft_connlimit)),
249 .eval = nft_connlimit_eval,
250 .init = nft_connlimit_init,
251 .destroy = nft_connlimit_destroy,
252 .clone = nft_connlimit_clone,
253 .destroy_clone = nft_connlimit_destroy_clone,
254 .dump = nft_connlimit_dump,
255 .gc = nft_connlimit_gc,
258 static struct nft_expr_type nft_connlimit_type __read_mostly = {
260 .ops = &nft_connlimit_ops,
261 .policy = nft_connlimit_policy,
262 .maxattr = NFTA_CONNLIMIT_MAX,
263 .flags = NFT_EXPR_STATEFUL | NFT_EXPR_GC,
264 .owner = THIS_MODULE,
267 static int __init nft_connlimit_module_init(void)
271 err = nft_register_obj(&nft_connlimit_obj_type);
275 err = nft_register_expr(&nft_connlimit_type);
281 nft_unregister_obj(&nft_connlimit_obj_type);
285 static void __exit nft_connlimit_module_exit(void)
287 nft_unregister_expr(&nft_connlimit_type);
288 nft_unregister_obj(&nft_connlimit_obj_type);
291 module_init(nft_connlimit_module_init);
292 module_exit(nft_connlimit_module_exit);
294 MODULE_LICENSE("GPL");
295 MODULE_AUTHOR("Pablo Neira Ayuso");
296 MODULE_ALIAS_NFT_EXPR("connlimit");
297 MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_CONNLIMIT);