net/netfilter/nft_cmp.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_offload.h>
 #include <net/netfilter/nf_tables.h>

 struct nft_cmp_expr {
 	struct nft_data		data;
 	enum nft_registers	sreg:8;
 	u8			len;
 	enum nft_cmp_ops	op:8;
 };

 void nft_cmp_eval(const struct nft_expr *expr,
 		  struct nft_regs *regs,
 		  const struct nft_pktinfo *pkt)
 {
 	const struct nft_cmp_expr *priv = nft_expr_priv(expr);
 	int d;

 	d = memcmp(&regs->data[priv->sreg], &priv->data, priv->len);
 	switch (priv->op) {
 	case NFT_CMP_EQ:
 		if (d != 0)
 			goto mismatch;
 		break;
 	case NFT_CMP_NEQ:
 		if (d == 0)
 			goto mismatch;
 		break;
 	case NFT_CMP_LT:
 		if (d == 0)
 			goto mismatch;
 		/* fall through */
 	case NFT_CMP_LTE:
 		if (d > 0)
 			goto mismatch;
 		break;
 	case NFT_CMP_GT:
 		if (d == 0)
 			goto mismatch;
 		/* fall through */
 	case NFT_CMP_GTE:
 		if (d < 0)
 			goto mismatch;
 		break;
 	}
 	return;

 mismatch:
 	regs->verdict.code = NFT_BREAK;
 }

 static const struct nla_policy nft_cmp_policy[NFTA_CMP_MAX + 1] = {
 	[NFTA_CMP_SREG]		= { .type = NLA_U32 },
 	[NFTA_CMP_OP]		= { .type = NLA_U32 },
 	[NFTA_CMP_DATA]		= { .type = NLA_NESTED },
 };

 static int nft_cmp_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
 			const struct nlattr * const tb[])
 {
 	struct nft_cmp_expr *priv = nft_expr_priv(expr);
 	struct nft_data_desc desc;
 	int err;

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

 	priv->sreg = nft_parse_register(tb[NFTA_CMP_SREG]);
 	err = nft_validate_register_load(priv->sreg, desc.len);
 	if (err < 0)
 		return err;

 	priv->op  = ntohl(nla_get_be32(tb[NFTA_CMP_OP]));
 	priv->len = desc.len;
 	return 0;
 }

 static int nft_cmp_dump(struct sk_buff *skb, const struct nft_expr *expr)
 {
 	const struct nft_cmp_expr *priv = nft_expr_priv(expr);

 	if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg))
 		goto nla_put_failure;
 	if (nla_put_be32(skb, NFTA_CMP_OP, htonl(priv->op)))
 		goto nla_put_failure;

 	if (nft_data_dump(skb, NFTA_CMP_DATA, &priv->data,
 			  NFT_DATA_VALUE, priv->len) < 0)
 		goto nla_put_failure;
 	return 0;

 nla_put_failure:
 	return -1;
 }

 static int __nft_cmp_offload(struct nft_offload_ctx *ctx,
 			     struct nft_flow_rule *flow,
 			     const struct nft_cmp_expr *priv)
 {
 	struct nft_offload_reg *reg = &ctx->regs[priv->sreg];
 	u8 *mask = (u8 *)&flow->match.mask;
 	u8 *key = (u8 *)&flow->match.key;

 	if (priv->op != NFT_CMP_EQ || reg->len != priv->len)
 		return -EOPNOTSUPP;

 	memcpy(key + reg->offset, &priv->data, priv->len);
 	memcpy(mask + reg->offset, &reg->mask, priv->len);

 	flow->match.dissector.used_keys |= BIT(reg->key);
 	flow->match.dissector.offset[reg->key] = reg->base_offset;

 	nft_offload_update_dependency(ctx, &priv->data, priv->len);

 	return 0;
 }

 static int nft_cmp_offload(struct nft_offload_ctx *ctx,
 			   struct nft_flow_rule *flow,
 			   const struct nft_expr *expr)
 {
 	const struct nft_cmp_expr *priv = nft_expr_priv(expr);

 	return __nft_cmp_offload(ctx, flow, priv);
 }

 static const struct nft_expr_ops nft_cmp_ops = {
 	.type		= &nft_cmp_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_cmp_expr)),
 	.eval		= nft_cmp_eval,
 	.init		= nft_cmp_init,
 	.dump		= nft_cmp_dump,
 	.offload	= nft_cmp_offload,
 };

 static int nft_cmp_fast_init(const struct nft_ctx *ctx,
 			     const struct nft_expr *expr,
 			     const struct nlattr * const tb[])
 {
 	struct nft_cmp_fast_expr *priv = nft_expr_priv(expr);
 	struct nft_data_desc desc;
 	struct nft_data data;
 	u32 mask;
 	int err;

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

 	priv->sreg = nft_parse_register(tb[NFTA_CMP_SREG]);
 	err = nft_validate_register_load(priv->sreg, desc.len);
 	if (err < 0)
 		return err;

 	desc.len *= BITS_PER_BYTE;
 	mask = nft_cmp_fast_mask(desc.len);

 	priv->data = data.data[0] & mask;
 	priv->len  = desc.len;
 	return 0;
 }

 static int nft_cmp_fast_offload(struct nft_offload_ctx *ctx,
 				struct nft_flow_rule *flow,
 				const struct nft_expr *expr)
 {
 	const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr);
 	struct nft_cmp_expr cmp = {
 		.data	= {
 			.data	= {
 				[0] = priv->data,
 			},
 		},
 		.sreg	= priv->sreg,
 		.len	= priv->len / BITS_PER_BYTE,
 		.op	= NFT_CMP_EQ,
 	};

 	return __nft_cmp_offload(ctx, flow, &cmp);
 }

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

 	if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg))
 		goto nla_put_failure;
 	if (nla_put_be32(skb, NFTA_CMP_OP, htonl(NFT_CMP_EQ)))
 		goto nla_put_failure;

 	data.data[0] = priv->data;
 	if (nft_data_dump(skb, NFTA_CMP_DATA, &data,
 			  NFT_DATA_VALUE, priv->len / BITS_PER_BYTE) < 0)
 		goto nla_put_failure;
 	return 0;

 nla_put_failure:
 	return -1;
 }

 const struct nft_expr_ops nft_cmp_fast_ops = {
 	.type		= &nft_cmp_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_cmp_fast_expr)),
 	.eval		= NULL,	/* inlined */
 	.init		= nft_cmp_fast_init,
 	.dump		= nft_cmp_fast_dump,
 	.offload	= nft_cmp_fast_offload,
 };

 static const struct nft_expr_ops *
 nft_cmp_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[])
 {
 	struct nft_data_desc desc;
 	struct nft_data data;
 	enum nft_cmp_ops op;
 	int err;

 	if (tb[NFTA_CMP_SREG] == NULL ||
 	    tb[NFTA_CMP_OP] == NULL ||
 	    tb[NFTA_CMP_DATA] == NULL)
 		return ERR_PTR(-EINVAL);

 	op = ntohl(nla_get_be32(tb[NFTA_CMP_OP]));
 	switch (op) {
 	case NFT_CMP_EQ:
 	case NFT_CMP_NEQ:
 	case NFT_CMP_LT:
 	case NFT_CMP_LTE:
 	case NFT_CMP_GT:
 	case NFT_CMP_GTE:
 		break;
 	default:
 		return ERR_PTR(-EINVAL);
 	}

 	err = nft_data_init(NULL, &data, sizeof(data), &desc,
 			    tb[NFTA_CMP_DATA]);
 	if (err < 0)
 		return ERR_PTR(err);

 	if (desc.type != NFT_DATA_VALUE) {
 		err = -EINVAL;
 		goto err1;
 	}

 	if (desc.len <= sizeof(u32) && op == NFT_CMP_EQ)
 		return &nft_cmp_fast_ops;

 	return &nft_cmp_ops;
 err1:
 	nft_data_release(&data, desc.type);
 	return ERR_PTR(-EINVAL);
 }

 struct nft_expr_type nft_cmp_type __read_mostly = {
 	.name		= "cmp",
 	.select_ops	= nft_cmp_select_ops,
 	.policy		= nft_cmp_policy,
 	.maxattr	= NFTA_CMP_MAX,
 	.owner		= THIS_MODULE,
 };
	// 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_offload.h>
	#include <net/netfilter/nf_tables.h>

	struct nft_cmp_expr {
	struct nft_data data;
	enum nft_registers sreg:8;
	u8 len;
	enum nft_cmp_ops op:8;
	};

	void nft_cmp_eval(const struct nft_expr *expr,
	struct nft_regs *regs,
	const struct nft_pktinfo *pkt)
	{
	const struct nft_cmp_expr *priv = nft_expr_priv(expr);
	int d;

	d = memcmp(&regs->data[priv->sreg], &priv->data, priv->len);
	switch (priv->op) {
	case NFT_CMP_EQ:
	if (d != 0)
	goto mismatch;
	break;
	case NFT_CMP_NEQ:
	if (d == 0)
	goto mismatch;
	break;
	case NFT_CMP_LT:
	if (d == 0)
	goto mismatch;
	/* fall through */
	case NFT_CMP_LTE:
	if (d > 0)
	goto mismatch;
	break;
	case NFT_CMP_GT:
	if (d == 0)
	goto mismatch;
	/* fall through */
	case NFT_CMP_GTE:
	if (d < 0)
	goto mismatch;
	break;
	}
	return;

	mismatch:
	regs->verdict.code = NFT_BREAK;
	}

	static const struct nla_policy nft_cmp_policy[NFTA_CMP_MAX + 1] = {
	[NFTA_CMP_SREG] = { .type = NLA_U32 },
	[NFTA_CMP_OP] = { .type = NLA_U32 },
	[NFTA_CMP_DATA] = { .type = NLA_NESTED },
	};

	static int nft_cmp_init(const struct nft_ctx ctx, const struct nft_expr expr,
	const struct nlattr * const tb[])
	{
	struct nft_cmp_expr *priv = nft_expr_priv(expr);
	struct nft_data_desc desc;
	int err;

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

	priv->sreg = nft_parse_register(tb[NFTA_CMP_SREG]);
	err = nft_validate_register_load(priv->sreg, desc.len);
	if (err < 0)
	return err;

	priv->op = ntohl(nla_get_be32(tb[NFTA_CMP_OP]));
	priv->len = desc.len;
	return 0;
	}

	static int nft_cmp_dump(struct sk_buff skb, const struct nft_expr expr)
	{
	const struct nft_cmp_expr *priv = nft_expr_priv(expr);

	if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg))
	goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_CMP_OP, htonl(priv->op)))
	goto nla_put_failure;

	if (nft_data_dump(skb, NFTA_CMP_DATA, &priv->data,
	NFT_DATA_VALUE, priv->len) < 0)
	goto nla_put_failure;
	return 0;

	nla_put_failure:
	return -1;
	}

	static int __nft_cmp_offload(struct nft_offload_ctx *ctx,
	struct nft_flow_rule *flow,
	const struct nft_cmp_expr *priv)
	{
	struct nft_offload_reg *reg = &ctx->regs[priv->sreg];
	u8 mask = (u8 )&flow->match.mask;
	u8 key = (u8 )&flow->match.key;

	if (priv->op != NFT_CMP_EQ \|\| reg->len != priv->len)
	return -EOPNOTSUPP;

	memcpy(key + reg->offset, &priv->data, priv->len);
	memcpy(mask + reg->offset, &reg->mask, priv->len);

	flow->match.dissector.used_keys \|= BIT(reg->key);
	flow->match.dissector.offset[reg->key] = reg->base_offset;

	nft_offload_update_dependency(ctx, &priv->data, priv->len);

	return 0;
	}

	static int nft_cmp_offload(struct nft_offload_ctx *ctx,
	struct nft_flow_rule *flow,
	const struct nft_expr *expr)
	{
	const struct nft_cmp_expr *priv = nft_expr_priv(expr);

	return __nft_cmp_offload(ctx, flow, priv);
	}

	static const struct nft_expr_ops nft_cmp_ops = {
	.type = &nft_cmp_type,
	.size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_expr)),
	.eval = nft_cmp_eval,
	.init = nft_cmp_init,
	.dump = nft_cmp_dump,
	.offload = nft_cmp_offload,
	};

	static int nft_cmp_fast_init(const struct nft_ctx *ctx,
	const struct nft_expr *expr,
	const struct nlattr * const tb[])
	{
	struct nft_cmp_fast_expr *priv = nft_expr_priv(expr);
	struct nft_data_desc desc;
	struct nft_data data;
	u32 mask;
	int err;

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

	priv->sreg = nft_parse_register(tb[NFTA_CMP_SREG]);
	err = nft_validate_register_load(priv->sreg, desc.len);
	if (err < 0)
	return err;

	desc.len *= BITS_PER_BYTE;
	mask = nft_cmp_fast_mask(desc.len);

	priv->data = data.data[0] & mask;
	priv->len = desc.len;
	return 0;
	}

	static int nft_cmp_fast_offload(struct nft_offload_ctx *ctx,
	struct nft_flow_rule *flow,
	const struct nft_expr *expr)
	{
	const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr);
	struct nft_cmp_expr cmp = {
	.data = {
	.data = {
	[0] = priv->data,
	},
	},
	.sreg = priv->sreg,
	.len = priv->len / BITS_PER_BYTE,
	.op = NFT_CMP_EQ,
	};

	return __nft_cmp_offload(ctx, flow, &cmp);
	}

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

	if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg))
	goto nla_put_failure;
	if (nla_put_be32(skb, NFTA_CMP_OP, htonl(NFT_CMP_EQ)))
	goto nla_put_failure;

	data.data[0] = priv->data;
	if (nft_data_dump(skb, NFTA_CMP_DATA, &data,
	NFT_DATA_VALUE, priv->len / BITS_PER_BYTE) < 0)
	goto nla_put_failure;
	return 0;

	nla_put_failure:
	return -1;
	}

	const struct nft_expr_ops nft_cmp_fast_ops = {
	.type = &nft_cmp_type,
	.size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_fast_expr)),
	.eval = NULL, /* inlined */
	.init = nft_cmp_fast_init,
	.dump = nft_cmp_fast_dump,
	.offload = nft_cmp_fast_offload,
	};

	static const struct nft_expr_ops *
	nft_cmp_select_ops(const struct nft_ctx ctx, const struct nlattr const tb[])
	{
	struct nft_data_desc desc;
	struct nft_data data;
	enum nft_cmp_ops op;
	int err;

	if (tb[NFTA_CMP_SREG] == NULL \|\|
	tb[NFTA_CMP_OP] == NULL \|\|
	tb[NFTA_CMP_DATA] == NULL)
	return ERR_PTR(-EINVAL);

	op = ntohl(nla_get_be32(tb[NFTA_CMP_OP]));
	switch (op) {
	case NFT_CMP_EQ:
	case NFT_CMP_NEQ:
	case NFT_CMP_LT:
	case NFT_CMP_LTE:
	case NFT_CMP_GT:
	case NFT_CMP_GTE:
	break;
	default:
	return ERR_PTR(-EINVAL);
	}

	err = nft_data_init(NULL, &data, sizeof(data), &desc,
	tb[NFTA_CMP_DATA]);
	if (err < 0)
	return ERR_PTR(err);

	if (desc.type != NFT_DATA_VALUE) {
	err = -EINVAL;
	goto err1;
	}

	if (desc.len <= sizeof(u32) && op == NFT_CMP_EQ)
	return &nft_cmp_fast_ops;

	return &nft_cmp_ops;
	err1:
	nft_data_release(&data, desc.type);
	return ERR_PTR(-EINVAL);
	}

	struct nft_expr_type nft_cmp_type __read_mostly = {
	.name = "cmp",
	.select_ops = nft_cmp_select_ops,
	.policy = nft_cmp_policy,
	.maxattr = NFTA_CMP_MAX,
	.owner = THIS_MODULE,
	};