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

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2008-2009 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/module.h>
 #include <linux/netlink.h>
 #include <linux/netfilter.h>
 #include <linux/netfilter/nf_tables.h>
 #include <net/netfilter/nf_tables_core.h>
 #include <net/netfilter/nf_tables.h>
 #include <net/netfilter/nf_tables_offload.h>

 struct nft_bitwise {
 	u8			sreg;
 	u8			dreg;
 	enum nft_bitwise_ops	op:8;
 	u8			len;
 	struct nft_data		mask;
 	struct nft_data		xor;
 	struct nft_data		data;
 };

 static void nft_bitwise_eval_bool(u32 *dst, const u32 *src,
 				  const struct nft_bitwise *priv)
 {
 	unsigned int i;

 	for (i = 0; i < DIV_ROUND_UP(priv->len, sizeof(u32)); i++)
 		dst[i] = (src[i] & priv->mask.data[i]) ^ priv->xor.data[i];
 }

 static void nft_bitwise_eval_lshift(u32 *dst, const u32 *src,
 				    const struct nft_bitwise *priv)
 {
 	u32 shift = priv->data.data[0];
 	unsigned int i;
 	u32 carry = 0;

 	for (i = DIV_ROUND_UP(priv->len, sizeof(u32)); i > 0; i--) {
 		dst[i - 1] = (src[i - 1] << shift) | carry;
 		carry = src[i - 1] >> (BITS_PER_TYPE(u32) - shift);
 	}
 }

 static void nft_bitwise_eval_rshift(u32 *dst, const u32 *src,
 				    const struct nft_bitwise *priv)
 {
 	u32 shift = priv->data.data[0];
 	unsigned int i;
 	u32 carry = 0;

 	for (i = 0; i < DIV_ROUND_UP(priv->len, sizeof(u32)); i++) {
 		dst[i] = carry | (src[i] >> shift);
 		carry = src[i] << (BITS_PER_TYPE(u32) - shift);
 	}
 }

 void nft_bitwise_eval(const struct nft_expr *expr,
 		      struct nft_regs *regs, const struct nft_pktinfo *pkt)
 {
 	const struct nft_bitwise *priv = nft_expr_priv(expr);
 	const u32 *src = &regs->data[priv->sreg];
 	u32 *dst = &regs->data[priv->dreg];

 	switch (priv->op) {
 	case NFT_BITWISE_BOOL:
 		nft_bitwise_eval_bool(dst, src, priv);
 		break;
 	case NFT_BITWISE_LSHIFT:
 		nft_bitwise_eval_lshift(dst, src, priv);
 		break;
 	case NFT_BITWISE_RSHIFT:
 		nft_bitwise_eval_rshift(dst, src, priv);
 		break;
 	}
 }

 static const struct nla_policy nft_bitwise_policy[NFTA_BITWISE_MAX + 1] = {
 	[NFTA_BITWISE_SREG]	= { .type = NLA_U32 },
 	[NFTA_BITWISE_DREG]	= { .type = NLA_U32 },
 	[NFTA_BITWISE_LEN]	= { .type = NLA_U32 },
 	[NFTA_BITWISE_MASK]	= { .type = NLA_NESTED },
 	[NFTA_BITWISE_XOR]	= { .type = NLA_NESTED },
 	[NFTA_BITWISE_OP]	= { .type = NLA_U32 },
 	[NFTA_BITWISE_DATA]	= { .type = NLA_NESTED },
 };

 static int nft_bitwise_init_bool(struct nft_bitwise *priv,
 				 const struct nlattr *const tb[])
 {
 	struct nft_data_desc mask = {
 		.type	= NFT_DATA_VALUE,
 		.size	= sizeof(priv->mask),
 		.len	= priv->len,
 	};
 	struct nft_data_desc xor = {
 		.type	= NFT_DATA_VALUE,
 		.size	= sizeof(priv->xor),
 		.len	= priv->len,
 	};
 	int err;

 	if (tb[NFTA_BITWISE_DATA])
 		return -EINVAL;

 	if (!tb[NFTA_BITWISE_MASK] ||
 	    !tb[NFTA_BITWISE_XOR])
 		return -EINVAL;

 	err = nft_data_init(NULL, &priv->mask, &mask, tb[NFTA_BITWISE_MASK]);
 	if (err < 0)
 		return err;

 	err = nft_data_init(NULL, &priv->xor, &xor, tb[NFTA_BITWISE_XOR]);
 	if (err < 0)
 		goto err_xor_err;

 	return 0;

 err_xor_err:
 	nft_data_release(&priv->mask, mask.type);

 	return err;
 }

 static int nft_bitwise_init_shift(struct nft_bitwise *priv,
 				  const struct nlattr *const tb[])
 {
 	struct nft_data_desc desc = {
 		.type	= NFT_DATA_VALUE,
 		.size	= sizeof(priv->data),
 		.len	= sizeof(u32),
 	};
 	int err;

 	if (tb[NFTA_BITWISE_MASK] ||
 	    tb[NFTA_BITWISE_XOR])
 		return -EINVAL;

 	if (!tb[NFTA_BITWISE_DATA])
 		return -EINVAL;

 	err = nft_data_init(NULL, &priv->data, &desc, tb[NFTA_BITWISE_DATA]);
 	if (err < 0)
 		return err;

 	if (priv->data.data[0] >= BITS_PER_TYPE(u32)) {
 		nft_data_release(&priv->data, desc.type);
 		return -EINVAL;
 	}

 	return 0;
 }

 static int nft_bitwise_init(const struct nft_ctx *ctx,
 			    const struct nft_expr *expr,
 			    const struct nlattr * const tb[])
 {
 	struct nft_bitwise *priv = nft_expr_priv(expr);
 	u32 len;
 	int err;

 	err = nft_parse_u32_check(tb[NFTA_BITWISE_LEN], U8_MAX, &len);
 	if (err < 0)
 		return err;

 	priv->len = len;

 	err = nft_parse_register_load(tb[NFTA_BITWISE_SREG], &priv->sreg,
 				      priv->len);
 	if (err < 0)
 		return err;

 	err = nft_parse_register_store(ctx, tb[NFTA_BITWISE_DREG],
 				       &priv->dreg, NULL, NFT_DATA_VALUE,
 				       priv->len);
 	if (err < 0)
 		return err;

 	if (tb[NFTA_BITWISE_OP]) {
 		priv->op = ntohl(nla_get_be32(tb[NFTA_BITWISE_OP]));
 		switch (priv->op) {
 		case NFT_BITWISE_BOOL:
 		case NFT_BITWISE_LSHIFT:
 		case NFT_BITWISE_RSHIFT:
 			break;
 		default:
 			return -EOPNOTSUPP;
 		}
 	} else {
 		priv->op = NFT_BITWISE_BOOL;
 	}

 	switch(priv->op) {
 	case NFT_BITWISE_BOOL:
 		err = nft_bitwise_init_bool(priv, tb);
 		break;
 	case NFT_BITWISE_LSHIFT:
 	case NFT_BITWISE_RSHIFT:
 		err = nft_bitwise_init_shift(priv, tb);
 		break;
 	}

 	return err;
 }

 static int nft_bitwise_dump_bool(struct sk_buff *skb,
 				 const struct nft_bitwise *priv)
 {
 	if (nft_data_dump(skb, NFTA_BITWISE_MASK, &priv->mask,
 			  NFT_DATA_VALUE, priv->len) < 0)
 		return -1;

 	if (nft_data_dump(skb, NFTA_BITWISE_XOR, &priv->xor,
 			  NFT_DATA_VALUE, priv->len) < 0)
 		return -1;

 	return 0;
 }

 static int nft_bitwise_dump_shift(struct sk_buff *skb,
 				  const struct nft_bitwise *priv)
 {
 	if (nft_data_dump(skb, NFTA_BITWISE_DATA, &priv->data,
 			  NFT_DATA_VALUE, sizeof(u32)) < 0)
 		return -1;
 	return 0;
 }

 static int nft_bitwise_dump(struct sk_buff *skb, const struct nft_expr *expr)
 {
 	const struct nft_bitwise *priv = nft_expr_priv(expr);
 	int err = 0;

 	if (nft_dump_register(skb, NFTA_BITWISE_SREG, priv->sreg))
 		return -1;
 	if (nft_dump_register(skb, NFTA_BITWISE_DREG, priv->dreg))
 		return -1;
 	if (nla_put_be32(skb, NFTA_BITWISE_LEN, htonl(priv->len)))
 		return -1;
 	if (nla_put_be32(skb, NFTA_BITWISE_OP, htonl(priv->op)))
 		return -1;

 	switch (priv->op) {
 	case NFT_BITWISE_BOOL:
 		err = nft_bitwise_dump_bool(skb, priv);
 		break;
 	case NFT_BITWISE_LSHIFT:
 	case NFT_BITWISE_RSHIFT:
 		err = nft_bitwise_dump_shift(skb, priv);
 		break;
 	}

 	return err;
 }

 static struct nft_data zero;

 static int nft_bitwise_offload(struct nft_offload_ctx *ctx,
 			       struct nft_flow_rule *flow,
 			       const struct nft_expr *expr)
 {
 	const struct nft_bitwise *priv = nft_expr_priv(expr);
 	struct nft_offload_reg *reg = &ctx->regs[priv->dreg];

 	if (priv->op != NFT_BITWISE_BOOL)
 		return -EOPNOTSUPP;

 	if (memcmp(&priv->xor, &zero, sizeof(priv->xor)) ||
 	    priv->sreg != priv->dreg || priv->len != reg->len)
 		return -EOPNOTSUPP;

 	memcpy(&reg->mask, &priv->mask, sizeof(priv->mask));

 	return 0;
 }

 static bool nft_bitwise_reduce(struct nft_regs_track *track,
 			       const struct nft_expr *expr)
 {
 	const struct nft_bitwise *priv = nft_expr_priv(expr);
 	const struct nft_bitwise *bitwise;
 	unsigned int regcount;
 	u8 dreg;
 	int i;

 	if (!track->regs[priv->sreg].selector)
 		return false;

 	bitwise = nft_expr_priv(track->regs[priv->dreg].selector);
 	if (track->regs[priv->sreg].selector == track->regs[priv->dreg].selector &&
 	    track->regs[priv->sreg].num_reg == 0 &&
 	    track->regs[priv->dreg].bitwise &&
 	    track->regs[priv->dreg].bitwise->ops == expr->ops &&
 	    priv->sreg == bitwise->sreg &&
 	    priv->dreg == bitwise->dreg &&
 	    priv->op == bitwise->op &&
 	    priv->len == bitwise->len &&
 	    !memcmp(&priv->mask, &bitwise->mask, sizeof(priv->mask)) &&
 	    !memcmp(&priv->xor, &bitwise->xor, sizeof(priv->xor)) &&
 	    !memcmp(&priv->data, &bitwise->data, sizeof(priv->data))) {
 		track->cur = expr;
 		return true;
 	}

 	if (track->regs[priv->sreg].bitwise ||
 	    track->regs[priv->sreg].num_reg != 0) {
 		nft_reg_track_cancel(track, priv->dreg, priv->len);
 		return false;
 	}

 	if (priv->sreg != priv->dreg) {
 		nft_reg_track_update(track, track->regs[priv->sreg].selector,
 				     priv->dreg, priv->len);
 	}

 	dreg = priv->dreg;
 	regcount = DIV_ROUND_UP(priv->len, NFT_REG32_SIZE);
 	for (i = 0; i < regcount; i++, dreg++)
 		track->regs[priv->dreg].bitwise = expr;

 	return false;
 }

 static const struct nft_expr_ops nft_bitwise_ops = {
 	.type		= &nft_bitwise_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_bitwise)),
 	.eval		= nft_bitwise_eval,
 	.init		= nft_bitwise_init,
 	.dump		= nft_bitwise_dump,
 	.reduce		= nft_bitwise_reduce,
 	.offload	= nft_bitwise_offload,
 };

 static int
 nft_bitwise_extract_u32_data(const struct nlattr * const tb, u32 *out)
 {
 	struct nft_data data;
 	struct nft_data_desc desc = {
 		.type	= NFT_DATA_VALUE,
 		.size	= sizeof(data),
 		.len	= sizeof(u32),
 	};
 	int err;

 	err = nft_data_init(NULL, &data, &desc, tb);
 	if (err < 0)
 		return err;

 	*out = data.data[0];

 	return 0;
 }

 static int nft_bitwise_fast_init(const struct nft_ctx *ctx,
 				 const struct nft_expr *expr,
 				 const struct nlattr * const tb[])
 {
 	struct nft_bitwise_fast_expr *priv = nft_expr_priv(expr);
 	int err;

 	err = nft_parse_register_load(tb[NFTA_BITWISE_SREG], &priv->sreg,
 				      sizeof(u32));
 	if (err < 0)
 		return err;

 	err = nft_parse_register_store(ctx, tb[NFTA_BITWISE_DREG], &priv->dreg,
 				       NULL, NFT_DATA_VALUE, sizeof(u32));
 	if (err < 0)
 		return err;

 	if (tb[NFTA_BITWISE_DATA])
 		return -EINVAL;

 	if (!tb[NFTA_BITWISE_MASK] ||
 	    !tb[NFTA_BITWISE_XOR])
 		return -EINVAL;

 	err = nft_bitwise_extract_u32_data(tb[NFTA_BITWISE_MASK], &priv->mask);
 	if (err < 0)
 		return err;

 	err = nft_bitwise_extract_u32_data(tb[NFTA_BITWISE_XOR], &priv->xor);
 	if (err < 0)
 		return err;

 	return 0;
 }

 static int
 nft_bitwise_fast_dump(struct sk_buff *skb, const struct nft_expr *expr)
 {
 	const struct nft_bitwise_fast_expr *priv = nft_expr_priv(expr);
 	struct nft_data data;

 	if (nft_dump_register(skb, NFTA_BITWISE_SREG, priv->sreg))
 		return -1;
 	if (nft_dump_register(skb, NFTA_BITWISE_DREG, priv->dreg))
 		return -1;
 	if (nla_put_be32(skb, NFTA_BITWISE_LEN, htonl(sizeof(u32))))
 		return -1;
 	if (nla_put_be32(skb, NFTA_BITWISE_OP, htonl(NFT_BITWISE_BOOL)))
 		return -1;

 	data.data[0] = priv->mask;
 	if (nft_data_dump(skb, NFTA_BITWISE_MASK, &data,
 			  NFT_DATA_VALUE, sizeof(u32)) < 0)
 		return -1;

 	data.data[0] = priv->xor;
 	if (nft_data_dump(skb, NFTA_BITWISE_XOR, &data,
 			  NFT_DATA_VALUE, sizeof(u32)) < 0)
 		return -1;

 	return 0;
 }

 static int nft_bitwise_fast_offload(struct nft_offload_ctx *ctx,
 				    struct nft_flow_rule *flow,
 				    const struct nft_expr *expr)
 {
 	const struct nft_bitwise_fast_expr *priv = nft_expr_priv(expr);
 	struct nft_offload_reg *reg = &ctx->regs[priv->dreg];

 	if (priv->xor || priv->sreg != priv->dreg || reg->len != sizeof(u32))
 		return -EOPNOTSUPP;

 	reg->mask.data[0] = priv->mask;
 	return 0;
 }

 static bool nft_bitwise_fast_reduce(struct nft_regs_track *track,
 				    const struct nft_expr *expr)
 {
 	const struct nft_bitwise_fast_expr *priv = nft_expr_priv(expr);
 	const struct nft_bitwise_fast_expr *bitwise;

 	if (!track->regs[priv->sreg].selector)
 		return false;

 	bitwise = nft_expr_priv(track->regs[priv->dreg].selector);
 	if (track->regs[priv->sreg].selector == track->regs[priv->dreg].selector &&
 	    track->regs[priv->dreg].bitwise &&
 	    track->regs[priv->dreg].bitwise->ops == expr->ops &&
 	    priv->sreg == bitwise->sreg &&
 	    priv->dreg == bitwise->dreg &&
 	    priv->mask == bitwise->mask &&
 	    priv->xor == bitwise->xor) {
 		track->cur = expr;
 		return true;
 	}

 	if (track->regs[priv->sreg].bitwise) {
 		nft_reg_track_cancel(track, priv->dreg, NFT_REG32_SIZE);
 		return false;
 	}

 	if (priv->sreg != priv->dreg) {
 		track->regs[priv->dreg].selector =
 			track->regs[priv->sreg].selector;
 	}
 	track->regs[priv->dreg].bitwise = expr;

 	return false;
 }

 const struct nft_expr_ops nft_bitwise_fast_ops = {
 	.type		= &nft_bitwise_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_bitwise_fast_expr)),
 	.eval		= NULL, /* inlined */
 	.init		= nft_bitwise_fast_init,
 	.dump		= nft_bitwise_fast_dump,
 	.reduce		= nft_bitwise_fast_reduce,
 	.offload	= nft_bitwise_fast_offload,
 };

 static const struct nft_expr_ops *
 nft_bitwise_select_ops(const struct nft_ctx *ctx,
 		       const struct nlattr * const tb[])
 {
 	int err;
 	u32 len;

 	if (!tb[NFTA_BITWISE_LEN] ||
 	    !tb[NFTA_BITWISE_SREG] ||
 	    !tb[NFTA_BITWISE_DREG])
 		return ERR_PTR(-EINVAL);

 	err = nft_parse_u32_check(tb[NFTA_BITWISE_LEN], U8_MAX, &len);
 	if (err < 0)
 		return ERR_PTR(err);

 	if (len != sizeof(u32))
 		return &nft_bitwise_ops;

 	if (tb[NFTA_BITWISE_OP] &&
 	    ntohl(nla_get_be32(tb[NFTA_BITWISE_OP])) != NFT_BITWISE_BOOL)
 		return &nft_bitwise_ops;

 	return &nft_bitwise_fast_ops;
 }

 struct nft_expr_type nft_bitwise_type __read_mostly = {
 	.name		= "bitwise",
 	.select_ops	= nft_bitwise_select_ops,
 	.policy		= nft_bitwise_policy,
 	.maxattr	= NFTA_BITWISE_MAX,
 	.owner		= THIS_MODULE,
 };

 bool nft_expr_reduce_bitwise(struct nft_regs_track *track,
 			     const struct nft_expr *expr)
 {
 	const struct nft_expr *last = track->last;
 	const struct nft_expr *next;

 	if (expr == last)
 		return false;

 	next = nft_expr_next(expr);
 	if (next->ops == &nft_bitwise_ops)
 		return nft_bitwise_reduce(track, next);
 	else if (next->ops == &nft_bitwise_fast_ops)
 		return nft_bitwise_fast_reduce(track, next);

 	return false;
 }
 EXPORT_SYMBOL_GPL(nft_expr_reduce_bitwise);
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (c) 2008-2009 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/module.h>
	#include <linux/netlink.h>
	#include <linux/netfilter.h>
	#include <linux/netfilter/nf_tables.h>
	#include <net/netfilter/nf_tables_core.h>
	#include <net/netfilter/nf_tables.h>
	#include <net/netfilter/nf_tables_offload.h>

	struct nft_bitwise {
	u8 sreg;
	u8 dreg;
	enum nft_bitwise_ops op:8;
	u8 len;
	struct nft_data mask;
	struct nft_data xor;
	struct nft_data data;
	};

	static void nft_bitwise_eval_bool(u32 dst, const u32 src,
	const struct nft_bitwise *priv)
	{
	unsigned int i;

	for (i = 0; i < DIV_ROUND_UP(priv->len, sizeof(u32)); i++)
	dst[i] = (src[i] & priv->mask.data[i]) ^ priv->xor.data[i];
	}

	static void nft_bitwise_eval_lshift(u32 dst, const u32 src,
	const struct nft_bitwise *priv)
	{
	u32 shift = priv->data.data[0];
	unsigned int i;
	u32 carry = 0;

	for (i = DIV_ROUND_UP(priv->len, sizeof(u32)); i > 0; i--) {
	dst[i - 1] = (src[i - 1] << shift) \| carry;
	carry = src[i - 1] >> (BITS_PER_TYPE(u32) - shift);
	}
	}

	static void nft_bitwise_eval_rshift(u32 dst, const u32 src,
	const struct nft_bitwise *priv)
	{
	u32 shift = priv->data.data[0];
	unsigned int i;
	u32 carry = 0;

	for (i = 0; i < DIV_ROUND_UP(priv->len, sizeof(u32)); i++) {
	dst[i] = carry \| (src[i] >> shift);
	carry = src[i] << (BITS_PER_TYPE(u32) - shift);
	}
	}

	void nft_bitwise_eval(const struct nft_expr *expr,
	struct nft_regs regs, const struct nft_pktinfo pkt)
	{
	const struct nft_bitwise *priv = nft_expr_priv(expr);
	const u32 *src = &regs->data[priv->sreg];
	u32 *dst = &regs->data[priv->dreg];

	switch (priv->op) {
	case NFT_BITWISE_BOOL:
	nft_bitwise_eval_bool(dst, src, priv);
	break;
	case NFT_BITWISE_LSHIFT:
	nft_bitwise_eval_lshift(dst, src, priv);
	break;
	case NFT_BITWISE_RSHIFT:
	nft_bitwise_eval_rshift(dst, src, priv);
	break;
	}
	}

	static const struct nla_policy nft_bitwise_policy[NFTA_BITWISE_MAX + 1] = {
	[NFTA_BITWISE_SREG] = { .type = NLA_U32 },
	[NFTA_BITWISE_DREG] = { .type = NLA_U32 },
	[NFTA_BITWISE_LEN] = { .type = NLA_U32 },
	[NFTA_BITWISE_MASK] = { .type = NLA_NESTED },
	[NFTA_BITWISE_XOR] = { .type = NLA_NESTED },
	[NFTA_BITWISE_OP] = { .type = NLA_U32 },
	[NFTA_BITWISE_DATA] = { .type = NLA_NESTED },
	};

	static int nft_bitwise_init_bool(struct nft_bitwise *priv,
	const struct nlattr *const tb[])
	{
	struct nft_data_desc mask = {
	.type = NFT_DATA_VALUE,
	.size = sizeof(priv->mask),
	.len = priv->len,
	};
	struct nft_data_desc xor = {
	.type = NFT_DATA_VALUE,
	.size = sizeof(priv->xor),
	.len = priv->len,
	};
	int err;

	if (tb[NFTA_BITWISE_DATA])
	return -EINVAL;

	if (!tb[NFTA_BITWISE_MASK] \|\|
	!tb[NFTA_BITWISE_XOR])
	return -EINVAL;

	err = nft_data_init(NULL, &priv->mask, &mask, tb[NFTA_BITWISE_MASK]);
	if (err < 0)
	return err;

	err = nft_data_init(NULL, &priv->xor, &xor, tb[NFTA_BITWISE_XOR]);
	if (err < 0)
	goto err_xor_err;

	return 0;

	err_xor_err:
	nft_data_release(&priv->mask, mask.type);

	return err;
	}

	static int nft_bitwise_init_shift(struct nft_bitwise *priv,
	const struct nlattr *const tb[])
	{
	struct nft_data_desc desc = {
	.type = NFT_DATA_VALUE,
	.size = sizeof(priv->data),
	.len = sizeof(u32),
	};
	int err;

	if (tb[NFTA_BITWISE_MASK] \|\|
	tb[NFTA_BITWISE_XOR])
	return -EINVAL;

	if (!tb[NFTA_BITWISE_DATA])
	return -EINVAL;

	err = nft_data_init(NULL, &priv->data, &desc, tb[NFTA_BITWISE_DATA]);
	if (err < 0)
	return err;

	if (priv->data.data[0] >= BITS_PER_TYPE(u32)) {
	nft_data_release(&priv->data, desc.type);
	return -EINVAL;
	}

	return 0;
	}

	static int nft_bitwise_init(const struct nft_ctx *ctx,
	const struct nft_expr *expr,
	const struct nlattr * const tb[])
	{
	struct nft_bitwise *priv = nft_expr_priv(expr);
	u32 len;
	int err;

	err = nft_parse_u32_check(tb[NFTA_BITWISE_LEN], U8_MAX, &len);
	if (err < 0)
	return err;

	priv->len = len;

	err = nft_parse_register_load(tb[NFTA_BITWISE_SREG], &priv->sreg,
	priv->len);
	if (err < 0)
	return err;

	err = nft_parse_register_store(ctx, tb[NFTA_BITWISE_DREG],
	&priv->dreg, NULL, NFT_DATA_VALUE,
	priv->len);
	if (err < 0)
	return err;

	if (tb[NFTA_BITWISE_OP]) {
	priv->op = ntohl(nla_get_be32(tb[NFTA_BITWISE_OP]));
	switch (priv->op) {
	case NFT_BITWISE_BOOL:
	case NFT_BITWISE_LSHIFT:
	case NFT_BITWISE_RSHIFT:
	break;
	default:
	return -EOPNOTSUPP;
	}
	} else {
	priv->op = NFT_BITWISE_BOOL;
	}

	switch(priv->op) {
	case NFT_BITWISE_BOOL:
	err = nft_bitwise_init_bool(priv, tb);
	break;
	case NFT_BITWISE_LSHIFT:
	case NFT_BITWISE_RSHIFT:
	err = nft_bitwise_init_shift(priv, tb);
	break;
	}

	return err;
	}

	static int nft_bitwise_dump_bool(struct sk_buff *skb,
	const struct nft_bitwise *priv)
	{
	if (nft_data_dump(skb, NFTA_BITWISE_MASK, &priv->mask,
	NFT_DATA_VALUE, priv->len) < 0)
	return -1;

	if (nft_data_dump(skb, NFTA_BITWISE_XOR, &priv->xor,
	NFT_DATA_VALUE, priv->len) < 0)
	return -1;

	return 0;
	}

	static int nft_bitwise_dump_shift(struct sk_buff *skb,
	const struct nft_bitwise *priv)
	{
	if (nft_data_dump(skb, NFTA_BITWISE_DATA, &priv->data,
	NFT_DATA_VALUE, sizeof(u32)) < 0)
	return -1;
	return 0;
	}

	static int nft_bitwise_dump(struct sk_buff skb, const struct nft_expr expr)
	{
	const struct nft_bitwise *priv = nft_expr_priv(expr);
	int err = 0;

	if (nft_dump_register(skb, NFTA_BITWISE_SREG, priv->sreg))
	return -1;
	if (nft_dump_register(skb, NFTA_BITWISE_DREG, priv->dreg))
	return -1;
	if (nla_put_be32(skb, NFTA_BITWISE_LEN, htonl(priv->len)))
	return -1;
	if (nla_put_be32(skb, NFTA_BITWISE_OP, htonl(priv->op)))
	return -1;

	switch (priv->op) {
	case NFT_BITWISE_BOOL:
	err = nft_bitwise_dump_bool(skb, priv);
	break;
	case NFT_BITWISE_LSHIFT:
	case NFT_BITWISE_RSHIFT:
	err = nft_bitwise_dump_shift(skb, priv);
	break;
	}

	return err;
	}

	static struct nft_data zero;

	static int nft_bitwise_offload(struct nft_offload_ctx *ctx,
	struct nft_flow_rule *flow,
	const struct nft_expr *expr)
	{
	const struct nft_bitwise *priv = nft_expr_priv(expr);
	struct nft_offload_reg *reg = &ctx->regs[priv->dreg];

	if (priv->op != NFT_BITWISE_BOOL)
	return -EOPNOTSUPP;

	if (memcmp(&priv->xor, &zero, sizeof(priv->xor)) \|\|
	priv->sreg != priv->dreg \|\| priv->len != reg->len)
	return -EOPNOTSUPP;

	memcpy(&reg->mask, &priv->mask, sizeof(priv->mask));

	return 0;
	}

	static bool nft_bitwise_reduce(struct nft_regs_track *track,
	const struct nft_expr *expr)
	{
	const struct nft_bitwise *priv = nft_expr_priv(expr);
	const struct nft_bitwise *bitwise;
	unsigned int regcount;
	u8 dreg;
	int i;

	if (!track->regs[priv->sreg].selector)
	return false;

	bitwise = nft_expr_priv(track->regs[priv->dreg].selector);
	if (track->regs[priv->sreg].selector == track->regs[priv->dreg].selector &&
	track->regs[priv->sreg].num_reg == 0 &&
	track->regs[priv->dreg].bitwise &&
	track->regs[priv->dreg].bitwise->ops == expr->ops &&
	priv->sreg == bitwise->sreg &&
	priv->dreg == bitwise->dreg &&
	priv->op == bitwise->op &&
	priv->len == bitwise->len &&
	!memcmp(&priv->mask, &bitwise->mask, sizeof(priv->mask)) &&
	!memcmp(&priv->xor, &bitwise->xor, sizeof(priv->xor)) &&
	!memcmp(&priv->data, &bitwise->data, sizeof(priv->data))) {
	track->cur = expr;
	return true;
	}

	if (track->regs[priv->sreg].bitwise \|\|
	track->regs[priv->sreg].num_reg != 0) {
	nft_reg_track_cancel(track, priv->dreg, priv->len);
	return false;
	}

	if (priv->sreg != priv->dreg) {
	nft_reg_track_update(track, track->regs[priv->sreg].selector,
	priv->dreg, priv->len);
	}

	dreg = priv->dreg;
	regcount = DIV_ROUND_UP(priv->len, NFT_REG32_SIZE);
	for (i = 0; i < regcount; i++, dreg++)
	track->regs[priv->dreg].bitwise = expr;

	return false;
	}

	static const struct nft_expr_ops nft_bitwise_ops = {
	.type = &nft_bitwise_type,
	.size = NFT_EXPR_SIZE(sizeof(struct nft_bitwise)),
	.eval = nft_bitwise_eval,
	.init = nft_bitwise_init,
	.dump = nft_bitwise_dump,
	.reduce = nft_bitwise_reduce,
	.offload = nft_bitwise_offload,
	};

	static int
	nft_bitwise_extract_u32_data(const struct nlattr * const tb, u32 *out)
	{
	struct nft_data data;
	struct nft_data_desc desc = {
	.type = NFT_DATA_VALUE,
	.size = sizeof(data),
	.len = sizeof(u32),
	};
	int err;

	err = nft_data_init(NULL, &data, &desc, tb);
	if (err < 0)
	return err;

	*out = data.data[0];

	return 0;
	}

	static int nft_bitwise_fast_init(const struct nft_ctx *ctx,
	const struct nft_expr *expr,
	const struct nlattr * const tb[])
	{
	struct nft_bitwise_fast_expr *priv = nft_expr_priv(expr);
	int err;

	err = nft_parse_register_load(tb[NFTA_BITWISE_SREG], &priv->sreg,
	sizeof(u32));
	if (err < 0)
	return err;

	err = nft_parse_register_store(ctx, tb[NFTA_BITWISE_DREG], &priv->dreg,
	NULL, NFT_DATA_VALUE, sizeof(u32));
	if (err < 0)
	return err;

	if (tb[NFTA_BITWISE_DATA])
	return -EINVAL;

	if (!tb[NFTA_BITWISE_MASK] \|\|
	!tb[NFTA_BITWISE_XOR])
	return -EINVAL;

	err = nft_bitwise_extract_u32_data(tb[NFTA_BITWISE_MASK], &priv->mask);
	if (err < 0)
	return err;

	err = nft_bitwise_extract_u32_data(tb[NFTA_BITWISE_XOR], &priv->xor);
	if (err < 0)
	return err;

	return 0;
	}

	static int
	nft_bitwise_fast_dump(struct sk_buff skb, const struct nft_expr expr)
	{
	const struct nft_bitwise_fast_expr *priv = nft_expr_priv(expr);
	struct nft_data data;

	if (nft_dump_register(skb, NFTA_BITWISE_SREG, priv->sreg))
	return -1;
	if (nft_dump_register(skb, NFTA_BITWISE_DREG, priv->dreg))
	return -1;
	if (nla_put_be32(skb, NFTA_BITWISE_LEN, htonl(sizeof(u32))))
	return -1;
	if (nla_put_be32(skb, NFTA_BITWISE_OP, htonl(NFT_BITWISE_BOOL)))
	return -1;

	data.data[0] = priv->mask;
	if (nft_data_dump(skb, NFTA_BITWISE_MASK, &data,
	NFT_DATA_VALUE, sizeof(u32)) < 0)
	return -1;

	data.data[0] = priv->xor;
	if (nft_data_dump(skb, NFTA_BITWISE_XOR, &data,
	NFT_DATA_VALUE, sizeof(u32)) < 0)
	return -1;

	return 0;
	}

	static int nft_bitwise_fast_offload(struct nft_offload_ctx *ctx,
	struct nft_flow_rule *flow,
	const struct nft_expr *expr)
	{
	const struct nft_bitwise_fast_expr *priv = nft_expr_priv(expr);
	struct nft_offload_reg *reg = &ctx->regs[priv->dreg];

	if (priv->xor \|\| priv->sreg != priv->dreg \|\| reg->len != sizeof(u32))
	return -EOPNOTSUPP;

	reg->mask.data[0] = priv->mask;
	return 0;
	}

	static bool nft_bitwise_fast_reduce(struct nft_regs_track *track,
	const struct nft_expr *expr)
	{
	const struct nft_bitwise_fast_expr *priv = nft_expr_priv(expr);
	const struct nft_bitwise_fast_expr *bitwise;

	if (!track->regs[priv->sreg].selector)
	return false;

	bitwise = nft_expr_priv(track->regs[priv->dreg].selector);
	if (track->regs[priv->sreg].selector == track->regs[priv->dreg].selector &&
	track->regs[priv->dreg].bitwise &&
	track->regs[priv->dreg].bitwise->ops == expr->ops &&
	priv->sreg == bitwise->sreg &&
	priv->dreg == bitwise->dreg &&
	priv->mask == bitwise->mask &&
	priv->xor == bitwise->xor) {
	track->cur = expr;
	return true;
	}

	if (track->regs[priv->sreg].bitwise) {
	nft_reg_track_cancel(track, priv->dreg, NFT_REG32_SIZE);
	return false;
	}

	if (priv->sreg != priv->dreg) {
	track->regs[priv->dreg].selector =
	track->regs[priv->sreg].selector;
	}
	track->regs[priv->dreg].bitwise = expr;

	return false;
	}

	const struct nft_expr_ops nft_bitwise_fast_ops = {
	.type = &nft_bitwise_type,
	.size = NFT_EXPR_SIZE(sizeof(struct nft_bitwise_fast_expr)),
	.eval = NULL, /* inlined */
	.init = nft_bitwise_fast_init,
	.dump = nft_bitwise_fast_dump,
	.reduce = nft_bitwise_fast_reduce,
	.offload = nft_bitwise_fast_offload,
	};

	static const struct nft_expr_ops *
	nft_bitwise_select_ops(const struct nft_ctx *ctx,
	const struct nlattr * const tb[])
	{
	int err;
	u32 len;

	if (!tb[NFTA_BITWISE_LEN] \|\|
	!tb[NFTA_BITWISE_SREG] \|\|
	!tb[NFTA_BITWISE_DREG])
	return ERR_PTR(-EINVAL);

	err = nft_parse_u32_check(tb[NFTA_BITWISE_LEN], U8_MAX, &len);
	if (err < 0)
	return ERR_PTR(err);

	if (len != sizeof(u32))
	return &nft_bitwise_ops;

	if (tb[NFTA_BITWISE_OP] &&
	ntohl(nla_get_be32(tb[NFTA_BITWISE_OP])) != NFT_BITWISE_BOOL)
	return &nft_bitwise_ops;

	return &nft_bitwise_fast_ops;
	}

	struct nft_expr_type nft_bitwise_type __read_mostly = {
	.name = "bitwise",
	.select_ops = nft_bitwise_select_ops,
	.policy = nft_bitwise_policy,
	.maxattr = NFTA_BITWISE_MAX,
	.owner = THIS_MODULE,
	};

	bool nft_expr_reduce_bitwise(struct nft_regs_track *track,
	const struct nft_expr *expr)
	{
	const struct nft_expr *last = track->last;
	const struct nft_expr *next;

	if (expr == last)
	return false;

	next = nft_expr_next(expr);
	if (next->ops == &nft_bitwise_ops)
	return nft_bitwise_reduce(track, next);
	else if (next->ops == &nft_bitwise_fast_ops)
	return nft_bitwise_fast_reduce(track, next);

	return false;
	}
	EXPORT_SYMBOL_GPL(nft_expr_reduce_bitwise);