[mirror_ubuntu-artful-kernel.git] / net / netfilter / nft_payload.c

/*
 * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * 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>

static void nft_payload_eval(const struct nft_expr *expr,
			     struct nft_data data[NFT_REG_MAX + 1],
			     const struct nft_pktinfo *pkt)
{
	const struct nft_payload *priv = nft_expr_priv(expr);
	const struct sk_buff *skb = pkt->skb;
	struct nft_data *dest = &data[priv->dreg];
	int offset;

	switch (priv->base) {
	case NFT_PAYLOAD_LL_HEADER:
		if (!skb_mac_header_was_set(skb))
			goto err;
		offset = skb_mac_header(skb) - skb->data;
		break;
	case NFT_PAYLOAD_NETWORK_HEADER:
		offset = skb_network_offset(skb);
		break;
	case NFT_PAYLOAD_TRANSPORT_HEADER:
		offset = pkt->xt.thoff;
		break;
	default:
		BUG();
	}
	offset += priv->offset;

	if (skb_copy_bits(skb, offset, dest->data, priv->len) < 0)
		goto err;
	return;
err:
	data[NFT_REG_VERDICT].verdict = NFT_BREAK;
}

static const struct nla_policy nft_payload_policy[NFTA_PAYLOAD_MAX + 1] = {
	[NFTA_PAYLOAD_DREG]	= { .type = NLA_U32 },
	[NFTA_PAYLOAD_BASE]	= { .type = NLA_U32 },
	[NFTA_PAYLOAD_OFFSET]	= { .type = NLA_U32 },
	[NFTA_PAYLOAD_LEN]	= { .type = NLA_U32 },
};

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

	priv->base   = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_BASE]));
	priv->offset = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_OFFSET]));
	priv->len    = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_LEN]));

	priv->dreg = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_DREG]));
	err = nft_validate_output_register(priv->dreg);
	if (err < 0)
		return err;
	return nft_validate_data_load(ctx, priv->dreg, NULL, NFT_DATA_VALUE);
}

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

	if (nla_put_be32(skb, NFTA_PAYLOAD_DREG, htonl(priv->dreg)) ||
	    nla_put_be32(skb, NFTA_PAYLOAD_BASE, htonl(priv->base)) ||
	    nla_put_be32(skb, NFTA_PAYLOAD_OFFSET, htonl(priv->offset)) ||
	    nla_put_be32(skb, NFTA_PAYLOAD_LEN, htonl(priv->len)))
		goto nla_put_failure;
	return 0;

nla_put_failure:
	return -1;
}

static struct nft_expr_type nft_payload_type;
static const struct nft_expr_ops nft_payload_ops = {
	.type		= &nft_payload_type,
	.size		= NFT_EXPR_SIZE(sizeof(struct nft_payload)),
	.eval		= nft_payload_eval,
	.init		= nft_payload_init,
	.dump		= nft_payload_dump,
};

const struct nft_expr_ops nft_payload_fast_ops = {
	.type		= &nft_payload_type,
	.size		= NFT_EXPR_SIZE(sizeof(struct nft_payload)),
	.eval		= nft_payload_eval,
	.init		= nft_payload_init,
	.dump		= nft_payload_dump,
};

static const struct nft_expr_ops *
nft_payload_select_ops(const struct nft_ctx *ctx,
		       const struct nlattr * const tb[])
{
	enum nft_payload_bases base;
	unsigned int offset, len;

	if (tb[NFTA_PAYLOAD_DREG] == NULL ||
	    tb[NFTA_PAYLOAD_BASE] == NULL ||
	    tb[NFTA_PAYLOAD_OFFSET] == NULL ||
	    tb[NFTA_PAYLOAD_LEN] == NULL)
		return ERR_PTR(-EINVAL);

	base = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_BASE]));
	switch (base) {
	case NFT_PAYLOAD_LL_HEADER:
	case NFT_PAYLOAD_NETWORK_HEADER:
	case NFT_PAYLOAD_TRANSPORT_HEADER:
		break;
	default:
		return ERR_PTR(-EOPNOTSUPP);
	}

	offset = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_OFFSET]));
	len = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_LEN]));
	if (len == 0 || len > FIELD_SIZEOF(struct nft_data, data))
		return ERR_PTR(-EINVAL);

	if (len <= 4 && is_power_of_2(len) && IS_ALIGNED(offset, len) &&
	    base != NFT_PAYLOAD_LL_HEADER)
		return &nft_payload_fast_ops;
	else
		return &nft_payload_ops;
}

static struct nft_expr_type nft_payload_type __read_mostly = {
	.name		= "payload",
	.select_ops	= nft_payload_select_ops,
	.policy		= nft_payload_policy,
	.maxattr	= NFTA_PAYLOAD_MAX,
	.owner		= THIS_MODULE,
};

int __init nft_payload_module_init(void)
{
	return nft_register_expr(&nft_payload_type);
}

void nft_payload_module_exit(void)
{
	nft_unregister_expr(&nft_payload_type);
}
Commit	Line	Data
96518518	1	/*
ef1f7df9	2	* Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
96518518 PM	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/module.h>
	14	#include <linux/netlink.h>
	15	#include <linux/netfilter.h>
	16	#include <linux/netfilter/nf_tables.h>
	17	#include <net/netfilter/nf_tables_core.h>
	18	#include <net/netfilter/nf_tables.h>
	19
96518518 PM	20	static void nft_payload_eval(const struct nft_expr *expr,
	21	struct nft_data data[NFT_REG_MAX + 1],
	22	const struct nft_pktinfo *pkt)
	23	{
	24	const struct nft_payload *priv = nft_expr_priv(expr);
	25	const struct sk_buff *skb = pkt->skb;
	26	struct nft_data *dest = &data[priv->dreg];
	27	int offset;
	28
	29	switch (priv->base) {
	30	case NFT_PAYLOAD_LL_HEADER:
	31	if (!skb_mac_header_was_set(skb))
	32	goto err;
	33	offset = skb_mac_header(skb) - skb->data;
	34	break;
	35	case NFT_PAYLOAD_NETWORK_HEADER:
	36	offset = skb_network_offset(skb);
	37	break;
	38	case NFT_PAYLOAD_TRANSPORT_HEADER:
c54032e0	39	offset = pkt->xt.thoff;
96518518 PM	40	break;
	41	default:
	42	BUG();
	43	}
	44	offset += priv->offset;
	45
	46	if (skb_copy_bits(skb, offset, dest->data, priv->len) < 0)
	47	goto err;
	48	return;
	49	err:
	50	data[NFT_REG_VERDICT].verdict = NFT_BREAK;
	51	}
	52
	53	static const struct nla_policy nft_payload_policy[NFTA_PAYLOAD_MAX + 1] = {
	54	[NFTA_PAYLOAD_DREG] = { .type = NLA_U32 },
	55	[NFTA_PAYLOAD_BASE] = { .type = NLA_U32 },
	56	[NFTA_PAYLOAD_OFFSET] = { .type = NLA_U32 },
	57	[NFTA_PAYLOAD_LEN] = { .type = NLA_U32 },
	58	};
	59
	60	static int nft_payload_init(const struct nft_ctx *ctx,
	61	const struct nft_expr *expr,
	62	const struct nlattr * const tb[])
	63	{
	64	struct nft_payload *priv = nft_expr_priv(expr);
	65	int err;
	66
c29b72e0	67	priv->base = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_BASE]));
96518518 PM	68	priv->offset = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_OFFSET]));
96518518 PM	69	priv->len = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_LEN]));
96518518 PM	70
	71	priv->dreg = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_DREG]));
	72	err = nft_validate_output_register(priv->dreg);
	73	if (err < 0)
	74	return err;
	75	return nft_validate_data_load(ctx, priv->dreg, NULL, NFT_DATA_VALUE);
	76	}
	77
	78	static int nft_payload_dump(struct sk_buff skb, const struct nft_expr expr)
	79	{
	80	const struct nft_payload *priv = nft_expr_priv(expr);
	81
	82	if (nla_put_be32(skb, NFTA_PAYLOAD_DREG, htonl(priv->dreg)) \|\|
	83	nla_put_be32(skb, NFTA_PAYLOAD_BASE, htonl(priv->base)) \|\|
	84	nla_put_be32(skb, NFTA_PAYLOAD_OFFSET, htonl(priv->offset)) \|\|
	85	nla_put_be32(skb, NFTA_PAYLOAD_LEN, htonl(priv->len)))
	86	goto nla_put_failure;
	87	return 0;
	88
	89	nla_put_failure:
	90	return -1;
	91	}
	92
ef1f7df9 PM	93	static struct nft_expr_type nft_payload_type;
	94	static const struct nft_expr_ops nft_payload_ops = {
	95	.type = &nft_payload_type,
96518518	96	.size = NFT_EXPR_SIZE(sizeof(struct nft_payload)),
96518518 PM	97	.eval = nft_payload_eval,
	98	.init = nft_payload_init,
	99	.dump = nft_payload_dump,
ef1f7df9 PM	100	};
ef1f7df9 PM	101
c29b72e0 PM	102	const struct nft_expr_ops nft_payload_fast_ops = {
	103	.type = &nft_payload_type,
	104	.size = NFT_EXPR_SIZE(sizeof(struct nft_payload)),
	105	.eval = nft_payload_eval,
	106	.init = nft_payload_init,
	107	.dump = nft_payload_dump,
	108	};
	109
0ca743a5 PNA	110	static const struct nft_expr_ops *
	111	nft_payload_select_ops(const struct nft_ctx *ctx,
	112	const struct nlattr * const tb[])
c29b72e0 PM	113	{
	114	enum nft_payload_bases base;
	115	unsigned int offset, len;
	116
	117	if (tb[NFTA_PAYLOAD_DREG] == NULL \|\|
	118	tb[NFTA_PAYLOAD_BASE] == NULL \|\|
	119	tb[NFTA_PAYLOAD_OFFSET] == NULL \|\|
	120	tb[NFTA_PAYLOAD_LEN] == NULL)
	121	return ERR_PTR(-EINVAL);
	122
	123	base = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_BASE]));
	124	switch (base) {
	125	case NFT_PAYLOAD_LL_HEADER:
	126	case NFT_PAYLOAD_NETWORK_HEADER:
	127	case NFT_PAYLOAD_TRANSPORT_HEADER:
	128	break;
	129	default:
	130	return ERR_PTR(-EOPNOTSUPP);
	131	}
	132
	133	offset = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_OFFSET]));
	134	len = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_LEN]));
	135	if (len == 0 \|\| len > FIELD_SIZEOF(struct nft_data, data))
	136	return ERR_PTR(-EINVAL);
	137
f627ed91 NA	138	if (len <= 4 && is_power_of_2(len) && IS_ALIGNED(offset, len) &&
f627ed91 NA	139	base != NFT_PAYLOAD_LL_HEADER)
c29b72e0 PM	140	return &nft_payload_fast_ops;
	141	else
	142	return &nft_payload_ops;
	143	}
	144
ef1f7df9 PM	145	static struct nft_expr_type nft_payload_type __read_mostly = {
ef1f7df9 PM	146	.name = "payload",
c29b72e0	147	.select_ops = nft_payload_select_ops,
96518518 PM	148	.policy = nft_payload_policy,
96518518 PM	149	.maxattr = NFTA_PAYLOAD_MAX,
ef1f7df9	150	.owner = THIS_MODULE,
96518518 PM	151	};
	152
	153	int __init nft_payload_module_init(void)
	154	{
ef1f7df9	155	return nft_register_expr(&nft_payload_type);
96518518 PM	156	}
	157
	158	void nft_payload_module_exit(void)
	159	{
ef1f7df9	160	nft_unregister_expr(&nft_payload_type);
96518518	161	}