net/netfilter/nft_lookup.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2009 Patrick McHardy <kaber@trash.net>
  *
  * Development of this code funded by Astaro AG (http://www.astaro.com/)
  */

 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/list.h>
 #include <linux/rbtree.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_tables_core.h>

 struct nft_lookup {
 	struct nft_set			*set;
 	u8				sreg;
 	u8				dreg;
 	bool				dreg_set;
 	bool				invert;
 	struct nft_set_binding		binding;
 };

 #ifdef CONFIG_MITIGATION_RETPOLINE
 bool nft_set_do_lookup(const struct net *net, const struct nft_set *set,
 		       const u32 *key, const struct nft_set_ext **ext)
 {
 	if (set->ops == &nft_set_hash_fast_type.ops)
 		return nft_hash_lookup_fast(net, set, key, ext);
 	if (set->ops == &nft_set_hash_type.ops)
 		return nft_hash_lookup(net, set, key, ext);

 	if (set->ops == &nft_set_rhash_type.ops)
 		return nft_rhash_lookup(net, set, key, ext);

 	if (set->ops == &nft_set_bitmap_type.ops)
 		return nft_bitmap_lookup(net, set, key, ext);

 	if (set->ops == &nft_set_pipapo_type.ops)
 		return nft_pipapo_lookup(net, set, key, ext);
 #if defined(CONFIG_X86_64) && !defined(CONFIG_UML)
 	if (set->ops == &nft_set_pipapo_avx2_type.ops)
 		return nft_pipapo_avx2_lookup(net, set, key, ext);
 #endif

 	if (set->ops == &nft_set_rbtree_type.ops)
 		return nft_rbtree_lookup(net, set, key, ext);

 	WARN_ON_ONCE(1);
 	return set->ops->lookup(net, set, key, ext);
 }
 EXPORT_SYMBOL_GPL(nft_set_do_lookup);
 #endif

 void nft_lookup_eval(const struct nft_expr *expr,
 		     struct nft_regs *regs,
 		     const struct nft_pktinfo *pkt)
 {
 	const struct nft_lookup *priv = nft_expr_priv(expr);
 	const struct nft_set *set = priv->set;
 	const struct nft_set_ext *ext = NULL;
 	const struct net *net = nft_net(pkt);
 	bool found;

 	found =	nft_set_do_lookup(net, set, &regs->data[priv->sreg], &ext) ^
 				  priv->invert;
 	if (!found) {
 		ext = nft_set_catchall_lookup(net, set);
 		if (!ext) {
 			regs->verdict.code = NFT_BREAK;
 			return;
 		}
 	}

 	if (ext) {
 		if (priv->dreg_set)
 			nft_data_copy(&regs->data[priv->dreg],
 				      nft_set_ext_data(ext), set->dlen);

 		nft_set_elem_update_expr(ext, regs, pkt);
 	}
 }

 static const struct nla_policy nft_lookup_policy[NFTA_LOOKUP_MAX + 1] = {
 	[NFTA_LOOKUP_SET]	= { .type = NLA_STRING,
 				    .len = NFT_SET_MAXNAMELEN - 1 },
 	[NFTA_LOOKUP_SET_ID]	= { .type = NLA_U32 },
 	[NFTA_LOOKUP_SREG]	= { .type = NLA_U32 },
 	[NFTA_LOOKUP_DREG]	= { .type = NLA_U32 },
 	[NFTA_LOOKUP_FLAGS]	=
 		NLA_POLICY_MASK(NLA_BE32, NFT_LOOKUP_F_INV),
 };

 static int nft_lookup_init(const struct nft_ctx *ctx,
 			   const struct nft_expr *expr,
 			   const struct nlattr * const tb[])
 {
 	struct nft_lookup *priv = nft_expr_priv(expr);
 	u8 genmask = nft_genmask_next(ctx->net);
 	struct nft_set *set;
 	u32 flags;
 	int err;

 	if (tb[NFTA_LOOKUP_SET] == NULL ||
 	    tb[NFTA_LOOKUP_SREG] == NULL)
 		return -EINVAL;

 	set = nft_set_lookup_global(ctx->net, ctx->table, tb[NFTA_LOOKUP_SET],
 				    tb[NFTA_LOOKUP_SET_ID], genmask);
 	if (IS_ERR(set))
 		return PTR_ERR(set);

 	err = nft_parse_register_load(tb[NFTA_LOOKUP_SREG], &priv->sreg,
 				      set->klen);
 	if (err < 0)
 		return err;

 	if (tb[NFTA_LOOKUP_FLAGS]) {
 		flags = ntohl(nla_get_be32(tb[NFTA_LOOKUP_FLAGS]));

 		if (flags & NFT_LOOKUP_F_INV)
 			priv->invert = true;
 	}

 	if (tb[NFTA_LOOKUP_DREG] != NULL) {
 		if (priv->invert)
 			return -EINVAL;
 		if (!(set->flags & NFT_SET_MAP))
 			return -EINVAL;

 		err = nft_parse_register_store(ctx, tb[NFTA_LOOKUP_DREG],
 					       &priv->dreg, NULL,
 					       nft_set_datatype(set),
 					       set->dlen);
 		if (err < 0)
 			return err;
 		priv->dreg_set = true;
 	} else if (set->flags & NFT_SET_MAP) {
 		/* Map given, but user asks for lookup only (i.e. to
 		 * ignore value assoicated with key).
 		 *
 		 * This makes no sense for anonymous maps since they are
 		 * scoped to the rule, but for named sets this can be useful.
 		 */
 		if (set->flags & NFT_SET_ANONYMOUS)
 			return -EINVAL;
 	}

 	priv->binding.flags = set->flags & NFT_SET_MAP;

 	err = nf_tables_bind_set(ctx, set, &priv->binding);
 	if (err < 0)
 		return err;

 	priv->set = set;
 	return 0;
 }

 static void nft_lookup_deactivate(const struct nft_ctx *ctx,
 				  const struct nft_expr *expr,
 				  enum nft_trans_phase phase)
 {
 	struct nft_lookup *priv = nft_expr_priv(expr);

 	nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
 }

 static void nft_lookup_activate(const struct nft_ctx *ctx,
 				const struct nft_expr *expr)
 {
 	struct nft_lookup *priv = nft_expr_priv(expr);

 	nf_tables_activate_set(ctx, priv->set);
 }

 static void nft_lookup_destroy(const struct nft_ctx *ctx,
 			       const struct nft_expr *expr)
 {
 	struct nft_lookup *priv = nft_expr_priv(expr);

 	nf_tables_destroy_set(ctx, priv->set);
 }

 static int nft_lookup_dump(struct sk_buff *skb,
 			   const struct nft_expr *expr, bool reset)
 {
 	const struct nft_lookup *priv = nft_expr_priv(expr);
 	u32 flags = priv->invert ? NFT_LOOKUP_F_INV : 0;

 	if (nla_put_string(skb, NFTA_LOOKUP_SET, priv->set->name))
 		goto nla_put_failure;
 	if (nft_dump_register(skb, NFTA_LOOKUP_SREG, priv->sreg))
 		goto nla_put_failure;
 	if (priv->dreg_set)
 		if (nft_dump_register(skb, NFTA_LOOKUP_DREG, priv->dreg))
 			goto nla_put_failure;
 	if (nla_put_be32(skb, NFTA_LOOKUP_FLAGS, htonl(flags)))
 		goto nla_put_failure;
 	return 0;

 nla_put_failure:
 	return -1;
 }

 static int nft_lookup_validate(const struct nft_ctx *ctx,
 			       const struct nft_expr *expr,
 			       const struct nft_data **d)
 {
 	const struct nft_lookup *priv = nft_expr_priv(expr);
 	struct nft_set_iter iter;

 	if (!(priv->set->flags & NFT_SET_MAP) ||
 	    priv->set->dtype != NFT_DATA_VERDICT)
 		return 0;

 	iter.genmask	= nft_genmask_next(ctx->net);
 	iter.type	= NFT_ITER_UPDATE;
 	iter.skip	= 0;
 	iter.count	= 0;
 	iter.err	= 0;
 	iter.fn		= nft_setelem_validate;

 	priv->set->ops->walk(ctx, priv->set, &iter);
 	if (!iter.err)
 		iter.err = nft_set_catchall_validate(ctx, priv->set);

 	if (iter.err < 0)
 		return iter.err;

 	return 0;
 }

 static bool nft_lookup_reduce(struct nft_regs_track *track,
 			      const struct nft_expr *expr)
 {
 	const struct nft_lookup *priv = nft_expr_priv(expr);

 	if (priv->set->flags & NFT_SET_MAP)
 		nft_reg_track_cancel(track, priv->dreg, priv->set->dlen);

 	return false;
 }

 static const struct nft_expr_ops nft_lookup_ops = {
 	.type		= &nft_lookup_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_lookup)),
 	.eval		= nft_lookup_eval,
 	.init		= nft_lookup_init,
 	.activate	= nft_lookup_activate,
 	.deactivate	= nft_lookup_deactivate,
 	.destroy	= nft_lookup_destroy,
 	.dump		= nft_lookup_dump,
 	.validate	= nft_lookup_validate,
 	.reduce		= nft_lookup_reduce,
 };

 struct nft_expr_type nft_lookup_type __read_mostly = {
 	.name		= "lookup",
 	.ops		= &nft_lookup_ops,
 	.policy		= nft_lookup_policy,
 	.maxattr	= NFTA_LOOKUP_MAX,
 	.owner		= THIS_MODULE,
 };
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (c) 2009 Patrick McHardy <kaber@trash.net>
	*
	* Development of this code funded by Astaro AG (http://www.astaro.com/)
	*/

	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/list.h>
	#include <linux/rbtree.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_tables_core.h>

	struct nft_lookup {
	struct nft_set *set;
	u8 sreg;
	u8 dreg;
	bool dreg_set;
	bool invert;
	struct nft_set_binding binding;
	};

	#ifdef CONFIG_MITIGATION_RETPOLINE
	bool nft_set_do_lookup(const struct net net, const struct nft_set set,
	const u32 key, const struct nft_set_ext *ext)
	{
	if (set->ops == &nft_set_hash_fast_type.ops)
	return nft_hash_lookup_fast(net, set, key, ext);
	if (set->ops == &nft_set_hash_type.ops)
	return nft_hash_lookup(net, set, key, ext);

	if (set->ops == &nft_set_rhash_type.ops)
	return nft_rhash_lookup(net, set, key, ext);

	if (set->ops == &nft_set_bitmap_type.ops)
	return nft_bitmap_lookup(net, set, key, ext);

	if (set->ops == &nft_set_pipapo_type.ops)
	return nft_pipapo_lookup(net, set, key, ext);
	#if defined(CONFIG_X86_64) && !defined(CONFIG_UML)
	if (set->ops == &nft_set_pipapo_avx2_type.ops)
	return nft_pipapo_avx2_lookup(net, set, key, ext);
	#endif

	if (set->ops == &nft_set_rbtree_type.ops)
	return nft_rbtree_lookup(net, set, key, ext);

	WARN_ON_ONCE(1);
	return set->ops->lookup(net, set, key, ext);
	}
	EXPORT_SYMBOL_GPL(nft_set_do_lookup);
	#endif

	void nft_lookup_eval(const struct nft_expr *expr,
	struct nft_regs *regs,
	const struct nft_pktinfo *pkt)
	{
	const struct nft_lookup *priv = nft_expr_priv(expr);
	const struct nft_set *set = priv->set;
	const struct nft_set_ext *ext = NULL;
	const struct net *net = nft_net(pkt);
	bool found;

	found = nft_set_do_lookup(net, set, &regs->data[priv->sreg], &ext) ^
	priv->invert;
	if (!found) {
	ext = nft_set_catchall_lookup(net, set);
	if (!ext) {
	regs->verdict.code = NFT_BREAK;
	return;
	}
	}

	if (ext) {
	if (priv->dreg_set)
	nft_data_copy(&regs->data[priv->dreg],
	nft_set_ext_data(ext), set->dlen);

	nft_set_elem_update_expr(ext, regs, pkt);
	}
	}

	static const struct nla_policy nft_lookup_policy[NFTA_LOOKUP_MAX + 1] = {
	[NFTA_LOOKUP_SET] = { .type = NLA_STRING,
	.len = NFT_SET_MAXNAMELEN - 1 },
	[NFTA_LOOKUP_SET_ID] = { .type = NLA_U32 },
	[NFTA_LOOKUP_SREG] = { .type = NLA_U32 },
	[NFTA_LOOKUP_DREG] = { .type = NLA_U32 },
	[NFTA_LOOKUP_FLAGS] =
	NLA_POLICY_MASK(NLA_BE32, NFT_LOOKUP_F_INV),
	};

	static int nft_lookup_init(const struct nft_ctx *ctx,
	const struct nft_expr *expr,
	const struct nlattr * const tb[])
	{
	struct nft_lookup *priv = nft_expr_priv(expr);
	u8 genmask = nft_genmask_next(ctx->net);
	struct nft_set *set;
	u32 flags;
	int err;

	if (tb[NFTA_LOOKUP_SET] == NULL \|\|
	tb[NFTA_LOOKUP_SREG] == NULL)
	return -EINVAL;

	set = nft_set_lookup_global(ctx->net, ctx->table, tb[NFTA_LOOKUP_SET],
	tb[NFTA_LOOKUP_SET_ID], genmask);
	if (IS_ERR(set))
	return PTR_ERR(set);

	err = nft_parse_register_load(tb[NFTA_LOOKUP_SREG], &priv->sreg,
	set->klen);
	if (err < 0)
	return err;

	if (tb[NFTA_LOOKUP_FLAGS]) {
	flags = ntohl(nla_get_be32(tb[NFTA_LOOKUP_FLAGS]));

	if (flags & NFT_LOOKUP_F_INV)
	priv->invert = true;
	}

	if (tb[NFTA_LOOKUP_DREG] != NULL) {
	if (priv->invert)
	return -EINVAL;
	if (!(set->flags & NFT_SET_MAP))
	return -EINVAL;

	err = nft_parse_register_store(ctx, tb[NFTA_LOOKUP_DREG],
	&priv->dreg, NULL,
	nft_set_datatype(set),
	set->dlen);
	if (err < 0)
	return err;
	priv->dreg_set = true;
	} else if (set->flags & NFT_SET_MAP) {
	/* Map given, but user asks for lookup only (i.e. to
	* ignore value assoicated with key).
	*
	* This makes no sense for anonymous maps since they are
	* scoped to the rule, but for named sets this can be useful.
	*/
	if (set->flags & NFT_SET_ANONYMOUS)
	return -EINVAL;
	}

	priv->binding.flags = set->flags & NFT_SET_MAP;

	err = nf_tables_bind_set(ctx, set, &priv->binding);
	if (err < 0)
	return err;

	priv->set = set;
	return 0;
	}

	static void nft_lookup_deactivate(const struct nft_ctx *ctx,
	const struct nft_expr *expr,
	enum nft_trans_phase phase)
	{
	struct nft_lookup *priv = nft_expr_priv(expr);

	nf_tables_deactivate_set(ctx, priv->set, &priv->binding, phase);
	}

	static void nft_lookup_activate(const struct nft_ctx *ctx,
	const struct nft_expr *expr)
	{
	struct nft_lookup *priv = nft_expr_priv(expr);

	nf_tables_activate_set(ctx, priv->set);
	}

	static void nft_lookup_destroy(const struct nft_ctx *ctx,
	const struct nft_expr *expr)
	{
	struct nft_lookup *priv = nft_expr_priv(expr);

	nf_tables_destroy_set(ctx, priv->set);
	}

	static int nft_lookup_dump(struct sk_buff *skb,
	const struct nft_expr *expr, bool reset)
	{
	const struct nft_lookup *priv = nft_expr_priv(expr);
	u32 flags = priv->invert ? NFT_LOOKUP_F_INV : 0;

	if (nla_put_string(skb, NFTA_LOOKUP_SET, priv->set->name))
	goto nla_put_failure;
	if (nft_dump_register(skb, NFTA_LOOKUP_SREG, priv->sreg))
	goto nla_put_failure;
	if (priv->dreg_set)
	if (nft_dump_register(skb, NFTA_LOOKUP_DREG, priv->dreg))
	goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_LOOKUP_FLAGS, htonl(flags)))
	goto nla_put_failure;
	return 0;

	nla_put_failure:
	return -1;
	}

	static int nft_lookup_validate(const struct nft_ctx *ctx,
	const struct nft_expr *expr,
	const struct nft_data **d)
	{
	const struct nft_lookup *priv = nft_expr_priv(expr);
	struct nft_set_iter iter;

	if (!(priv->set->flags & NFT_SET_MAP) \|\|
	priv->set->dtype != NFT_DATA_VERDICT)
	return 0;

	iter.genmask = nft_genmask_next(ctx->net);
	iter.type = NFT_ITER_UPDATE;
	iter.skip = 0;
	iter.count = 0;
	iter.err = 0;
	iter.fn = nft_setelem_validate;

	priv->set->ops->walk(ctx, priv->set, &iter);
	if (!iter.err)
	iter.err = nft_set_catchall_validate(ctx, priv->set);

	if (iter.err < 0)
	return iter.err;

	return 0;
	}

	static bool nft_lookup_reduce(struct nft_regs_track *track,
	const struct nft_expr *expr)
	{
	const struct nft_lookup *priv = nft_expr_priv(expr);

	if (priv->set->flags & NFT_SET_MAP)
	nft_reg_track_cancel(track, priv->dreg, priv->set->dlen);

	return false;
	}

	static const struct nft_expr_ops nft_lookup_ops = {
	.type = &nft_lookup_type,
	.size = NFT_EXPR_SIZE(sizeof(struct nft_lookup)),
	.eval = nft_lookup_eval,
	.init = nft_lookup_init,
	.activate = nft_lookup_activate,
	.deactivate = nft_lookup_deactivate,
	.destroy = nft_lookup_destroy,
	.dump = nft_lookup_dump,
	.validate = nft_lookup_validate,
	.reduce = nft_lookup_reduce,
	};

	struct nft_expr_type nft_lookup_type __read_mostly = {
	.name = "lookup",
	.ops = &nft_lookup_ops,
	.policy = nft_lookup_policy,
	.maxattr = NFTA_LOOKUP_MAX,
	.owner = THIS_MODULE,
	};