1 /*
2  * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
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 
20 struct nft_byteorder {
21 	enum nft_registers	sreg:8;
22 	enum nft_registers	dreg:8;
23 	enum nft_byteorder_ops	op:8;
24 	u8			len;
25 	u8			size;
26 };
27 
nft_byteorder_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)28 static void nft_byteorder_eval(const struct nft_expr *expr,
29 			       struct nft_regs *regs,
30 			       const struct nft_pktinfo *pkt)
31 {
32 	const struct nft_byteorder *priv = nft_expr_priv(expr);
33 	u32 *src = &regs->data[priv->sreg];
34 	u32 *dst = &regs->data[priv->dreg];
35 	union { u32 u32; u16 u16; } *s, *d;
36 	unsigned int i;
37 
38 	s = (void *)src;
39 	d = (void *)dst;
40 
41 	switch (priv->size) {
42 	case 4:
43 		switch (priv->op) {
44 		case NFT_BYTEORDER_NTOH:
45 			for (i = 0; i < priv->len / 4; i++)
46 				d[i].u32 = ntohl((__force __be32)s[i].u32);
47 			break;
48 		case NFT_BYTEORDER_HTON:
49 			for (i = 0; i < priv->len / 4; i++)
50 				d[i].u32 = (__force __u32)htonl(s[i].u32);
51 			break;
52 		}
53 		break;
54 	case 2:
55 		switch (priv->op) {
56 		case NFT_BYTEORDER_NTOH:
57 			for (i = 0; i < priv->len / 2; i++)
58 				d[i].u16 = ntohs((__force __be16)s[i].u16);
59 			break;
60 		case NFT_BYTEORDER_HTON:
61 			for (i = 0; i < priv->len / 2; i++)
62 				d[i].u16 = (__force __u16)htons(s[i].u16);
63 			break;
64 		}
65 		break;
66 	}
67 }
68 
69 static const struct nla_policy nft_byteorder_policy[NFTA_BYTEORDER_MAX + 1] = {
70 	[NFTA_BYTEORDER_SREG]	= { .type = NLA_U32 },
71 	[NFTA_BYTEORDER_DREG]	= { .type = NLA_U32 },
72 	[NFTA_BYTEORDER_OP]	= { .type = NLA_U32 },
73 	[NFTA_BYTEORDER_LEN]	= { .type = NLA_U32 },
74 	[NFTA_BYTEORDER_SIZE]	= { .type = NLA_U32 },
75 };
76 
nft_byteorder_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])77 static int nft_byteorder_init(const struct nft_ctx *ctx,
78 			      const struct nft_expr *expr,
79 			      const struct nlattr * const tb[])
80 {
81 	struct nft_byteorder *priv = nft_expr_priv(expr);
82 	int err;
83 
84 	if (tb[NFTA_BYTEORDER_SREG] == NULL ||
85 	    tb[NFTA_BYTEORDER_DREG] == NULL ||
86 	    tb[NFTA_BYTEORDER_LEN] == NULL ||
87 	    tb[NFTA_BYTEORDER_SIZE] == NULL ||
88 	    tb[NFTA_BYTEORDER_OP] == NULL)
89 		return -EINVAL;
90 
91 	priv->op = ntohl(nla_get_be32(tb[NFTA_BYTEORDER_OP]));
92 	switch (priv->op) {
93 	case NFT_BYTEORDER_NTOH:
94 	case NFT_BYTEORDER_HTON:
95 		break;
96 	default:
97 		return -EINVAL;
98 	}
99 
100 	priv->size = ntohl(nla_get_be32(tb[NFTA_BYTEORDER_SIZE]));
101 	switch (priv->size) {
102 	case 2:
103 	case 4:
104 		break;
105 	default:
106 		return -EINVAL;
107 	}
108 
109 	priv->sreg = nft_parse_register(tb[NFTA_BYTEORDER_SREG]);
110 	priv->len  = ntohl(nla_get_be32(tb[NFTA_BYTEORDER_LEN]));
111 	err = nft_validate_register_load(priv->sreg, priv->len);
112 	if (err < 0)
113 		return err;
114 
115 	priv->dreg = nft_parse_register(tb[NFTA_BYTEORDER_DREG]);
116 	return nft_validate_register_store(ctx, priv->dreg, NULL,
117 					   NFT_DATA_VALUE, priv->len);
118 }
119 
nft_byteorder_dump(struct sk_buff * skb,const struct nft_expr * expr)120 static int nft_byteorder_dump(struct sk_buff *skb, const struct nft_expr *expr)
121 {
122 	const struct nft_byteorder *priv = nft_expr_priv(expr);
123 
124 	if (nft_dump_register(skb, NFTA_BYTEORDER_SREG, priv->sreg))
125 		goto nla_put_failure;
126 	if (nft_dump_register(skb, NFTA_BYTEORDER_DREG, priv->dreg))
127 		goto nla_put_failure;
128 	if (nla_put_be32(skb, NFTA_BYTEORDER_OP, htonl(priv->op)))
129 		goto nla_put_failure;
130 	if (nla_put_be32(skb, NFTA_BYTEORDER_LEN, htonl(priv->len)))
131 		goto nla_put_failure;
132 	if (nla_put_be32(skb, NFTA_BYTEORDER_SIZE, htonl(priv->size)))
133 		goto nla_put_failure;
134 	return 0;
135 
136 nla_put_failure:
137 	return -1;
138 }
139 
140 static struct nft_expr_type nft_byteorder_type;
141 static const struct nft_expr_ops nft_byteorder_ops = {
142 	.type		= &nft_byteorder_type,
143 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_byteorder)),
144 	.eval		= nft_byteorder_eval,
145 	.init		= nft_byteorder_init,
146 	.dump		= nft_byteorder_dump,
147 };
148 
149 static struct nft_expr_type nft_byteorder_type __read_mostly = {
150 	.name		= "byteorder",
151 	.ops		= &nft_byteorder_ops,
152 	.policy		= nft_byteorder_policy,
153 	.maxattr	= NFTA_BYTEORDER_MAX,
154 	.owner		= THIS_MODULE,
155 };
156 
nft_byteorder_module_init(void)157 int __init nft_byteorder_module_init(void)
158 {
159 	return nft_register_expr(&nft_byteorder_type);
160 }
161 
nft_byteorder_module_exit(void)162 void nft_byteorder_module_exit(void)
163 {
164 	nft_unregister_expr(&nft_byteorder_type);
165 }
166