1/*
  2 * Copyright (c) 2009 Patrick McHardy <kaber@trash.net>
  3 *
  4 * This program is free software; you can redistribute it and/or modify
  5 * it under the terms of the GNU General Public License version 2 as
  6 * published by the Free Software Foundation.
  7 *
  8 * Development of this code funded by Astaro AG (http://www.astaro.com/)
  9 */
 10
 11#include <linux/kernel.h>
 12#include <linux/init.h>
 13#include <linux/list.h>
 14#include <linux/rbtree.h>
 15#include <linux/netlink.h>
 16#include <linux/netfilter.h>
 17#include <linux/netfilter/nf_tables.h>
 18#include <net/netfilter/nf_tables.h>
 19#include <net/netfilter/nf_tables_core.h>
 20
 21struct nft_lookup {
 22	struct nft_set			*set;
 23	enum nft_registers		sreg:8;
 24	enum nft_registers		dreg:8;
 25	bool				invert;
 26	struct nft_set_binding		binding;
 27};
 28
 29static void nft_lookup_eval(const struct nft_expr *expr,
 30			    struct nft_regs *regs,
 31			    const struct nft_pktinfo *pkt)
 32{
 33	const struct nft_lookup *priv = nft_expr_priv(expr);
 34	const struct nft_set *set = priv->set;
 35	const struct nft_set_ext *ext;
 36	bool found;
 37
 38	found = set->ops->lookup(nft_net(pkt), set, &regs->data[priv->sreg],
 39				 &ext) ^ priv->invert;
 40	if (!found) {
 41		regs->verdict.code = NFT_BREAK;
 42		return;
 43	}
 44
 45	if (set->flags & NFT_SET_MAP)
 46		nft_data_copy(&regs->data[priv->dreg],
 47			      nft_set_ext_data(ext), set->dlen);
 48
 49}
 50
 51static const struct nla_policy nft_lookup_policy[NFTA_LOOKUP_MAX + 1] = {
 52	[NFTA_LOOKUP_SET]	= { .type = NLA_STRING,
 53				    .len = NFT_SET_MAXNAMELEN - 1 },
 54	[NFTA_LOOKUP_SET_ID]	= { .type = NLA_U32 },
 55	[NFTA_LOOKUP_SREG]	= { .type = NLA_U32 },
 56	[NFTA_LOOKUP_DREG]	= { .type = NLA_U32 },
 57	[NFTA_LOOKUP_FLAGS]	= { .type = NLA_U32 },
 58};
 59
 60static int nft_lookup_init(const struct nft_ctx *ctx,
 61			   const struct nft_expr *expr,
 62			   const struct nlattr * const tb[])
 63{
 64	struct nft_lookup *priv = nft_expr_priv(expr);
 65	u8 genmask = nft_genmask_next(ctx->net);
 66	struct nft_set *set;
 67	u32 flags;
 68	int err;
 69
 70	if (tb[NFTA_LOOKUP_SET] == NULL ||
 71	    tb[NFTA_LOOKUP_SREG] == NULL)
 72		return -EINVAL;
 73
 74	set = nf_tables_set_lookup(ctx->table, tb[NFTA_LOOKUP_SET], genmask);
 75	if (IS_ERR(set)) {
 76		if (tb[NFTA_LOOKUP_SET_ID]) {
 77			set = nf_tables_set_lookup_byid(ctx->net,
 78							tb[NFTA_LOOKUP_SET_ID],
 79							genmask);
 80		}
 81		if (IS_ERR(set))
 82			return PTR_ERR(set);
 83	}
 84
 85	if (set->flags & NFT_SET_EVAL)
 86		return -EOPNOTSUPP;
 87
 88	priv->sreg = nft_parse_register(tb[NFTA_LOOKUP_SREG]);
 89	err = nft_validate_register_load(priv->sreg, set->klen);
 90	if (err < 0)
 91		return err;
 92
 93	if (tb[NFTA_LOOKUP_FLAGS]) {
 94		flags = ntohl(nla_get_be32(tb[NFTA_LOOKUP_FLAGS]));
 95
 96		if (flags & ~NFT_LOOKUP_F_INV)
 97			return -EINVAL;
 98
 99		if (flags & NFT_LOOKUP_F_INV) {
100			if (set->flags & NFT_SET_MAP)
101				return -EINVAL;
102			priv->invert = true;
103		}
104	}
105
106	if (tb[NFTA_LOOKUP_DREG] != NULL) {
107		if (priv->invert)
108			return -EINVAL;
109		if (!(set->flags & NFT_SET_MAP))
110			return -EINVAL;
111
112		priv->dreg = nft_parse_register(tb[NFTA_LOOKUP_DREG]);
113		err = nft_validate_register_store(ctx, priv->dreg, NULL,
114						  set->dtype, set->dlen);
115		if (err < 0)
116			return err;
117	} else if (set->flags & NFT_SET_MAP)
118		return -EINVAL;
119
120	priv->binding.flags = set->flags & NFT_SET_MAP;
121
122	err = nf_tables_bind_set(ctx, set, &priv->binding);
123	if (err < 0)
124		return err;
125
126	priv->set = set;
127	return 0;
128}
129
130static void nft_lookup_destroy(const struct nft_ctx *ctx,
131			       const struct nft_expr *expr)
132{
133	struct nft_lookup *priv = nft_expr_priv(expr);
134
135	nf_tables_unbind_set(ctx, priv->set, &priv->binding);
136}
137
138static int nft_lookup_dump(struct sk_buff *skb, const struct nft_expr *expr)
139{
140	const struct nft_lookup *priv = nft_expr_priv(expr);
141	u32 flags = priv->invert ? NFT_LOOKUP_F_INV : 0;
142
143	if (nla_put_string(skb, NFTA_LOOKUP_SET, priv->set->name))
144		goto nla_put_failure;
145	if (nft_dump_register(skb, NFTA_LOOKUP_SREG, priv->sreg))
146		goto nla_put_failure;
147	if (priv->set->flags & NFT_SET_MAP)
148		if (nft_dump_register(skb, NFTA_LOOKUP_DREG, priv->dreg))
149			goto nla_put_failure;
150	if (nla_put_be32(skb, NFTA_LOOKUP_FLAGS, htonl(flags)))
151		goto nla_put_failure;
152	return 0;
153
154nla_put_failure:
155	return -1;
156}
157
158static const struct nft_expr_ops nft_lookup_ops = {
159	.type		= &nft_lookup_type,
160	.size		= NFT_EXPR_SIZE(sizeof(struct nft_lookup)),
161	.eval		= nft_lookup_eval,
162	.init		= nft_lookup_init,
163	.destroy	= nft_lookup_destroy,
164	.dump		= nft_lookup_dump,
165};
166
167struct nft_expr_type nft_lookup_type __read_mostly = {
168	.name		= "lookup",
169	.ops		= &nft_lookup_ops,
170	.policy		= nft_lookup_policy,
171	.maxattr	= NFTA_LOOKUP_MAX,
172	.owner		= THIS_MODULE,
173};