1 /*
2  * Copyright (c) 2014 Intel Corporation
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  */
9 
10 #include <linux/kernel.h>
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/netlink.h>
14 #include <linux/netfilter.h>
15 #include <linux/netfilter/nf_tables.h>
16 #include <net/netfilter/nf_tables.h>
17 #include <net/netfilter/nft_meta.h>
18 
19 #include "../br_private.h"
20 
21 static void nft_meta_bridge_get_eval(const struct nft_expr *expr,
22 				     struct nft_regs *regs,
23 				     const struct nft_pktinfo *pkt)
24 {
25 	const struct nft_meta *priv = nft_expr_priv(expr);
26 	const struct net_device *in = pkt->in, *out = pkt->out;
27 	u32 *dest = &regs->data[priv->dreg];
28 	const struct net_bridge_port *p;
29 
30 	switch (priv->key) {
31 	case NFT_META_BRI_IIFNAME:
32 		if (in == NULL || (p = br_port_get_rcu(in)) == NULL)
33 			goto err;
34 		break;
35 	case NFT_META_BRI_OIFNAME:
36 		if (out == NULL || (p = br_port_get_rcu(out)) == NULL)
37 			goto err;
38 		break;
39 	default:
40 		goto out;
41 	}
42 
43 	strncpy((char *)dest, p->br->dev->name, IFNAMSIZ);
44 	return;
45 out:
46 	return nft_meta_get_eval(expr, regs, pkt);
47 err:
48 	regs->verdict.code = NFT_BREAK;
49 }
50 
51 static int nft_meta_bridge_get_init(const struct nft_ctx *ctx,
52 				    const struct nft_expr *expr,
53 				    const struct nlattr * const tb[])
54 {
55 	struct nft_meta *priv = nft_expr_priv(expr);
56 	unsigned int len;
57 
58 	priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
59 	switch (priv->key) {
60 	case NFT_META_BRI_IIFNAME:
61 	case NFT_META_BRI_OIFNAME:
62 		len = IFNAMSIZ;
63 		break;
64 	default:
65 		return nft_meta_get_init(ctx, expr, tb);
66 	}
67 
68 	priv->dreg = nft_parse_register(tb[NFTA_META_DREG]);
69 	return nft_validate_register_store(ctx, priv->dreg, NULL,
70 					   NFT_DATA_VALUE, len);
71 }
72 
73 static struct nft_expr_type nft_meta_bridge_type;
74 static const struct nft_expr_ops nft_meta_bridge_get_ops = {
75 	.type		= &nft_meta_bridge_type,
76 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_meta)),
77 	.eval		= nft_meta_bridge_get_eval,
78 	.init		= nft_meta_bridge_get_init,
79 	.dump		= nft_meta_get_dump,
80 };
81 
82 static const struct nft_expr_ops nft_meta_bridge_set_ops = {
83 	.type		= &nft_meta_bridge_type,
84 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_meta)),
85 	.eval		= nft_meta_set_eval,
86 	.init		= nft_meta_set_init,
87 	.destroy	= nft_meta_set_destroy,
88 	.dump		= nft_meta_set_dump,
89 };
90 
91 static const struct nft_expr_ops *
92 nft_meta_bridge_select_ops(const struct nft_ctx *ctx,
93 			   const struct nlattr * const tb[])
94 {
95 	if (tb[NFTA_META_KEY] == NULL)
96 		return ERR_PTR(-EINVAL);
97 
98 	if (tb[NFTA_META_DREG] && tb[NFTA_META_SREG])
99 		return ERR_PTR(-EINVAL);
100 
101 	if (tb[NFTA_META_DREG])
102 		return &nft_meta_bridge_get_ops;
103 
104 	if (tb[NFTA_META_SREG])
105 		return &nft_meta_bridge_set_ops;
106 
107 	return ERR_PTR(-EINVAL);
108 }
109 
110 static struct nft_expr_type nft_meta_bridge_type __read_mostly = {
111 	.family         = NFPROTO_BRIDGE,
112 	.name           = "meta",
113 	.select_ops     = &nft_meta_bridge_select_ops,
114 	.policy         = nft_meta_policy,
115 	.maxattr        = NFTA_META_MAX,
116 	.owner          = THIS_MODULE,
117 };
118 
119 static int __init nft_meta_bridge_module_init(void)
120 {
121 	return nft_register_expr(&nft_meta_bridge_type);
122 }
123 
124 static void __exit nft_meta_bridge_module_exit(void)
125 {
126 	nft_unregister_expr(&nft_meta_bridge_type);
127 }
128 
129 module_init(nft_meta_bridge_module_init);
130 module_exit(nft_meta_bridge_module_exit);
131 
132 MODULE_LICENSE("GPL");
133 MODULE_AUTHOR("Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>");
134 MODULE_ALIAS_NFT_AF_EXPR(AF_BRIDGE, "meta");
135