1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (c) 2015 Patrick McHardy <kaber@trash.net>
  4 */
  5
  6#include <linux/kernel.h>
  7#include <linux/module.h>
  8#include <linux/init.h>
  9#include <linux/netlink.h>
 10#include <linux/netfilter.h>
 11#include <linux/netfilter/nf_tables.h>
 12#include <net/netfilter/nf_tables.h>
 13#include <net/netfilter/nf_tables_core.h>
 14
 15struct nft_dynset {
 16	struct nft_set			*set;
 17	struct nft_set_ext_tmpl		tmpl;
 18	enum nft_dynset_ops		op:8;
 19	enum nft_registers		sreg_key:8;
 20	enum nft_registers		sreg_data:8;
 21	bool				invert;
 22	u64				timeout;
 23	struct nft_expr			*expr;
 24	struct nft_set_binding		binding;
 25};
 26
 27static void *nft_dynset_new(struct nft_set *set, const struct nft_expr *expr,
 28			    struct nft_regs *regs)
 29{
 30	const struct nft_dynset *priv = nft_expr_priv(expr);
 31	struct nft_set_ext *ext;
 32	u64 timeout;
 33	void *elem;
 34
 35	if (!atomic_add_unless(&set->nelems, 1, set->size))
 36		return NULL;
 37
 38	timeout = priv->timeout ? : set->timeout;
 39	elem = nft_set_elem_init(set, &priv->tmpl,
 40				 &regs->data[priv->sreg_key], NULL,
 41				 &regs->data[priv->sreg_data],
 42				 timeout, 0, GFP_ATOMIC);
 43	if (elem == NULL)
 44		goto err1;
 45
 46	ext = nft_set_elem_ext(set, elem);
 47	if (priv->expr != NULL &&
 48	    nft_expr_clone(nft_set_ext_expr(ext), priv->expr) < 0)
 49		goto err2;
 50
 51	return elem;
 52
 53err2:
 54	nft_set_elem_destroy(set, elem, false);
 55err1:
 56	if (set->size)
 57		atomic_dec(&set->nelems);
 58	return NULL;
 59}
 60
 61void nft_dynset_eval(const struct nft_expr *expr,
 62		     struct nft_regs *regs, const struct nft_pktinfo *pkt)
 63{
 64	const struct nft_dynset *priv = nft_expr_priv(expr);
 65	struct nft_set *set = priv->set;
 66	const struct nft_set_ext *ext;
 67	u64 timeout;
 68
 69	if (priv->op == NFT_DYNSET_OP_DELETE) {
 70		set->ops->delete(set, &regs->data[priv->sreg_key]);
 71		return;
 72	}
 73
 74	if (set->ops->update(set, &regs->data[priv->sreg_key], nft_dynset_new,
 75			     expr, regs, &ext)) {
 76		if (priv->op == NFT_DYNSET_OP_UPDATE &&
 77		    nft_set_ext_exists(ext, NFT_SET_EXT_EXPIRATION)) {
 78			timeout = priv->timeout ? : set->timeout;
 79			*nft_set_ext_expiration(ext) = get_jiffies_64() + timeout;
 80		}
 81
 82		nft_set_elem_update_expr(ext, regs, pkt);
 83
 84		if (priv->invert)
 85			regs->verdict.code = NFT_BREAK;
 86		return;
 87	}
 88
 89	if (!priv->invert)
 90		regs->verdict.code = NFT_BREAK;
 91}
 92
 93static const struct nla_policy nft_dynset_policy[NFTA_DYNSET_MAX + 1] = {
 94	[NFTA_DYNSET_SET_NAME]	= { .type = NLA_STRING,
 95				    .len = NFT_SET_MAXNAMELEN - 1 },
 96	[NFTA_DYNSET_SET_ID]	= { .type = NLA_U32 },
 97	[NFTA_DYNSET_OP]	= { .type = NLA_U32 },
 98	[NFTA_DYNSET_SREG_KEY]	= { .type = NLA_U32 },
 99	[NFTA_DYNSET_SREG_DATA]	= { .type = NLA_U32 },
100	[NFTA_DYNSET_TIMEOUT]	= { .type = NLA_U64 },
101	[NFTA_DYNSET_EXPR]	= { .type = NLA_NESTED },
102	[NFTA_DYNSET_FLAGS]	= { .type = NLA_U32 },
103};
104
105static int nft_dynset_init(const struct nft_ctx *ctx,
106			   const struct nft_expr *expr,
107			   const struct nlattr * const tb[])
108{
109	struct nft_dynset *priv = nft_expr_priv(expr);
110	u8 genmask = nft_genmask_next(ctx->net);
111	struct nft_set *set;
112	u64 timeout;
113	int err;
114
115	lockdep_assert_held(&ctx->net->nft.commit_mutex);
116
117	if (tb[NFTA_DYNSET_SET_NAME] == NULL ||
118	    tb[NFTA_DYNSET_OP] == NULL ||
119	    tb[NFTA_DYNSET_SREG_KEY] == NULL)
120		return -EINVAL;
121
122	if (tb[NFTA_DYNSET_FLAGS]) {
123		u32 flags = ntohl(nla_get_be32(tb[NFTA_DYNSET_FLAGS]));
124
125		if (flags & ~NFT_DYNSET_F_INV)
126			return -EINVAL;
127		if (flags & NFT_DYNSET_F_INV)
128			priv->invert = true;
129	}
130
131	set = nft_set_lookup_global(ctx->net, ctx->table,
132				    tb[NFTA_DYNSET_SET_NAME],
133				    tb[NFTA_DYNSET_SET_ID], genmask);
134	if (IS_ERR(set))
135		return PTR_ERR(set);
136
137	if (set->ops->update == NULL)
138		return -EOPNOTSUPP;
139
140	if (set->flags & NFT_SET_CONSTANT)
141		return -EBUSY;
142
143	priv->op = ntohl(nla_get_be32(tb[NFTA_DYNSET_OP]));
144	switch (priv->op) {
145	case NFT_DYNSET_OP_ADD:
146	case NFT_DYNSET_OP_DELETE:
147		break;
148	case NFT_DYNSET_OP_UPDATE:
149		if (!(set->flags & NFT_SET_TIMEOUT))
150			return -EOPNOTSUPP;
151		break;
152	default:
153		return -EOPNOTSUPP;
154	}
155
156	timeout = 0;
157	if (tb[NFTA_DYNSET_TIMEOUT] != NULL) {
158		if (!(set->flags & NFT_SET_TIMEOUT))
159			return -EINVAL;
160		timeout = msecs_to_jiffies(be64_to_cpu(nla_get_be64(
161						tb[NFTA_DYNSET_TIMEOUT])));
162	}
163
164	priv->sreg_key = nft_parse_register(tb[NFTA_DYNSET_SREG_KEY]);
165	err = nft_validate_register_load(priv->sreg_key, set->klen);
166	if (err < 0)
167		return err;
168
169	if (tb[NFTA_DYNSET_SREG_DATA] != NULL) {
170		if (!(set->flags & NFT_SET_MAP))
171			return -EINVAL;
172		if (set->dtype == NFT_DATA_VERDICT)
173			return -EOPNOTSUPP;
174
175		priv->sreg_data = nft_parse_register(tb[NFTA_DYNSET_SREG_DATA]);
176		err = nft_validate_register_load(priv->sreg_data, set->dlen);
177		if (err < 0)
178			return err;
179	} else if (set->flags & NFT_SET_MAP)
180		return -EINVAL;
181
182	if (tb[NFTA_DYNSET_EXPR] != NULL) {
183		if (!(set->flags & NFT_SET_EVAL))
184			return -EINVAL;
185
186		priv->expr = nft_set_elem_expr_alloc(ctx, set,
187						     tb[NFTA_DYNSET_EXPR]);
188		if (IS_ERR(priv->expr))
189			return PTR_ERR(priv->expr);
190
191		if (set->expr && set->expr->ops != priv->expr->ops) {
192			err = -EOPNOTSUPP;
193			goto err_expr_free;
194		}
195	}
196
197	nft_set_ext_prepare(&priv->tmpl);
198	nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_KEY, set->klen);
199	if (set->flags & NFT_SET_MAP)
200		nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_DATA, set->dlen);
201	if (priv->expr != NULL)
202		nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_EXPR,
203				       priv->expr->ops->size);
204	if (set->flags & NFT_SET_TIMEOUT) {
205		if (timeout || set->timeout)
206			nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_EXPIRATION);
207	}
208
209	priv->timeout = timeout;
210
211	err = nf_tables_bind_set(ctx, set, &priv->binding);
212	if (err < 0)
213		goto err_expr_free;
214
215	if (set->size == 0)
216		set->size = 0xffff;
217
218	priv->set = set;
219	return 0;
220
221err_expr_free:
222	if (priv->expr != NULL)
223		nft_expr_destroy(ctx, priv->expr);
224	return err;
225}
226
227static void nft_dynset_deactivate(const struct nft_ctx *ctx,
228				  const struct nft_expr *expr,
229				  enum nft_trans_phase phase)
230{
231	struct nft_dynset *priv = nft_expr_priv(expr);
232
233	nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
234}
235
236static void nft_dynset_activate(const struct nft_ctx *ctx,
237				const struct nft_expr *expr)
238{
239	struct nft_dynset *priv = nft_expr_priv(expr);
240
241	priv->set->use++;
242}
243
244static void nft_dynset_destroy(const struct nft_ctx *ctx,
245			       const struct nft_expr *expr)
246{
247	struct nft_dynset *priv = nft_expr_priv(expr);
248
249	if (priv->expr != NULL)
250		nft_expr_destroy(ctx, priv->expr);
251
252	nf_tables_destroy_set(ctx, priv->set);
253}
254
255static int nft_dynset_dump(struct sk_buff *skb, const struct nft_expr *expr)
256{
257	const struct nft_dynset *priv = nft_expr_priv(expr);
258	u32 flags = priv->invert ? NFT_DYNSET_F_INV : 0;
259
260	if (nft_dump_register(skb, NFTA_DYNSET_SREG_KEY, priv->sreg_key))
261		goto nla_put_failure;
262	if (priv->set->flags & NFT_SET_MAP &&
263	    nft_dump_register(skb, NFTA_DYNSET_SREG_DATA, priv->sreg_data))
264		goto nla_put_failure;
265	if (nla_put_be32(skb, NFTA_DYNSET_OP, htonl(priv->op)))
266		goto nla_put_failure;
267	if (nla_put_string(skb, NFTA_DYNSET_SET_NAME, priv->set->name))
268		goto nla_put_failure;
269	if (nla_put_be64(skb, NFTA_DYNSET_TIMEOUT,
270			 cpu_to_be64(jiffies_to_msecs(priv->timeout)),
271			 NFTA_DYNSET_PAD))
272		goto nla_put_failure;
273	if (priv->expr && nft_expr_dump(skb, NFTA_DYNSET_EXPR, priv->expr))
274		goto nla_put_failure;
275	if (nla_put_be32(skb, NFTA_DYNSET_FLAGS, htonl(flags)))
276		goto nla_put_failure;
277	return 0;
278
279nla_put_failure:
280	return -1;
281}
282
283static const struct nft_expr_ops nft_dynset_ops = {
284	.type		= &nft_dynset_type,
285	.size		= NFT_EXPR_SIZE(sizeof(struct nft_dynset)),
286	.eval		= nft_dynset_eval,
287	.init		= nft_dynset_init,
288	.destroy	= nft_dynset_destroy,
289	.activate	= nft_dynset_activate,
290	.deactivate	= nft_dynset_deactivate,
291	.dump		= nft_dynset_dump,
292};
293
294struct nft_expr_type nft_dynset_type __read_mostly = {
295	.name		= "dynset",
296	.ops		= &nft_dynset_ops,
297	.policy		= nft_dynset_policy,
298	.maxattr	= NFTA_DYNSET_MAX,
299	.owner		= THIS_MODULE,
300};