nft_byteorder.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
  4 *
  5 * Development of this code funded by Astaro AG (http://www.astaro.com/)
  6 */
  7
  8#include <linux/unaligned.h>
  9#include <linux/kernel.h>
 10#include <linux/init.h>
 11#include <linux/module.h>
 12#include <linux/netlink.h>
 13#include <linux/netfilter.h>
 14#include <linux/netfilter/nf_tables.h>
 15#include <net/netfilter/nf_tables_core.h>
 16#include <net/netfilter/nf_tables.h>
 17
 18struct nft_byteorder {
 19	u8			sreg;
 20	u8			dreg;
 21	enum nft_byteorder_ops	op:8;
 22	u8			len;
 23	u8			size;
 24};
 25
 26void nft_byteorder_eval(const struct nft_expr *expr,
 27			struct nft_regs *regs,
 28			const struct nft_pktinfo *pkt)
 29{
 30	const struct nft_byteorder *priv = nft_expr_priv(expr);
 31	u32 *src = &regs->data[priv->sreg];
 32	u32 *dst = &regs->data[priv->dreg];
 33	u16 *s16, *d16;
 34	unsigned int i;
 35
 36	s16 = (void *)src;
 37	d16 = (void *)dst;
 38
 39	switch (priv->size) {
 40	case 8: {
 41		u64 *dst64 = (void *)dst;
 42		u64 src64;
 43
 44		switch (priv->op) {
 45		case NFT_BYTEORDER_NTOH:
 46			for (i = 0; i < priv->len / 8; i++) {
 47				src64 = nft_reg_load64(&src[i]);
 48				nft_reg_store64(&dst64[i],
 49						be64_to_cpu((__force __be64)src64));
 50			}
 51			break;
 52		case NFT_BYTEORDER_HTON:
 53			for (i = 0; i < priv->len / 8; i++) {
 54				src64 = (__force __u64)
 55					cpu_to_be64(nft_reg_load64(&src[i]));
 56				nft_reg_store64(&dst64[i], src64);
 57			}
 58			break;
 59		}
 60		break;
 61	}
 62	case 4:
 63		switch (priv->op) {
 64		case NFT_BYTEORDER_NTOH:
 65			for (i = 0; i < priv->len / 4; i++)
 66				dst[i] = ntohl((__force __be32)src[i]);
 67			break;
 68		case NFT_BYTEORDER_HTON:
 69			for (i = 0; i < priv->len / 4; i++)
 70				dst[i] = (__force __u32)htonl(src[i]);
 71			break;
 72		}
 73		break;
 74	case 2:
 75		switch (priv->op) {
 76		case NFT_BYTEORDER_NTOH:
 77			for (i = 0; i < priv->len / 2; i++)
 78				d16[i] = ntohs((__force __be16)s16[i]);
 79			break;
 80		case NFT_BYTEORDER_HTON:
 81			for (i = 0; i < priv->len / 2; i++)
 82				d16[i] = (__force __u16)htons(s16[i]);
 83			break;
 84		}
 85		break;
 86	}
 87}
 88
 89static const struct nla_policy nft_byteorder_policy[NFTA_BYTEORDER_MAX + 1] = {
 90	[NFTA_BYTEORDER_SREG]	= { .type = NLA_U32 },
 91	[NFTA_BYTEORDER_DREG]	= { .type = NLA_U32 },
 92	[NFTA_BYTEORDER_OP]	= NLA_POLICY_MAX(NLA_BE32, 255),
 93	[NFTA_BYTEORDER_LEN]	= NLA_POLICY_MAX(NLA_BE32, 255),
 94	[NFTA_BYTEORDER_SIZE]	= NLA_POLICY_MAX(NLA_BE32, 255),
 95};
 96
 97static int nft_byteorder_init(const struct nft_ctx *ctx,
 98			      const struct nft_expr *expr,
 99			      const struct nlattr * const tb[])
100{
101	struct nft_byteorder *priv = nft_expr_priv(expr);
102	u32 size, len;
103	int err;
104
105	if (tb[NFTA_BYTEORDER_SREG] == NULL ||
106	    tb[NFTA_BYTEORDER_DREG] == NULL ||
107	    tb[NFTA_BYTEORDER_LEN] == NULL ||
108	    tb[NFTA_BYTEORDER_SIZE] == NULL ||
109	    tb[NFTA_BYTEORDER_OP] == NULL)
110		return -EINVAL;
111
112	priv->op = ntohl(nla_get_be32(tb[NFTA_BYTEORDER_OP]));
113	switch (priv->op) {
114	case NFT_BYTEORDER_NTOH:
115	case NFT_BYTEORDER_HTON:
116		break;
117	default:
118		return -EINVAL;
119	}
120
121	err = nft_parse_u32_check(tb[NFTA_BYTEORDER_SIZE], U8_MAX, &size);
122	if (err < 0)
123		return err;
124
125	priv->size = size;
126
127	switch (priv->size) {
128	case 2:
129	case 4:
130	case 8:
131		break;
132	default:
133		return -EINVAL;
134	}
135
136	err = nft_parse_u32_check(tb[NFTA_BYTEORDER_LEN], U8_MAX, &len);
137	if (err < 0)
138		return err;
139
140	priv->len = len;
141
142	err = nft_parse_register_load(ctx, tb[NFTA_BYTEORDER_SREG], &priv->sreg,
143				      priv->len);
144	if (err < 0)
145		return err;
146
147	return nft_parse_register_store(ctx, tb[NFTA_BYTEORDER_DREG],
148					&priv->dreg, NULL, NFT_DATA_VALUE,
149					priv->len);
150}
151
152static int nft_byteorder_dump(struct sk_buff *skb,
153			      const struct nft_expr *expr, bool reset)
154{
155	const struct nft_byteorder *priv = nft_expr_priv(expr);
156
157	if (nft_dump_register(skb, NFTA_BYTEORDER_SREG, priv->sreg))
158		goto nla_put_failure;
159	if (nft_dump_register(skb, NFTA_BYTEORDER_DREG, priv->dreg))
160		goto nla_put_failure;
161	if (nla_put_be32(skb, NFTA_BYTEORDER_OP, htonl(priv->op)))
162		goto nla_put_failure;
163	if (nla_put_be32(skb, NFTA_BYTEORDER_LEN, htonl(priv->len)))
164		goto nla_put_failure;
165	if (nla_put_be32(skb, NFTA_BYTEORDER_SIZE, htonl(priv->size)))
166		goto nla_put_failure;
167	return 0;
168
169nla_put_failure:
170	return -1;
171}
172
173static bool nft_byteorder_reduce(struct nft_regs_track *track,
174				 const struct nft_expr *expr)
175{
176	struct nft_byteorder *priv = nft_expr_priv(expr);
177
178	nft_reg_track_cancel(track, priv->dreg, priv->len);
179
180	return false;
181}
182
183static const struct nft_expr_ops nft_byteorder_ops = {
184	.type		= &nft_byteorder_type,
185	.size		= NFT_EXPR_SIZE(sizeof(struct nft_byteorder)),
186	.eval		= nft_byteorder_eval,
187	.init		= nft_byteorder_init,
188	.dump		= nft_byteorder_dump,
189	.reduce		= nft_byteorder_reduce,
190};
191
192struct nft_expr_type nft_byteorder_type __read_mostly = {
193	.name		= "byteorder",
194	.ops		= &nft_byteorder_ops,
195	.policy		= nft_byteorder_policy,
196	.maxattr	= NFTA_BYTEORDER_MAX,
197	.owner		= THIS_MODULE,
198};