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