1 /*
2 * Copyright (c) 2015 Pablo Neira Ayuso <pablo@netfilter.org>
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 as published by
6 * the Free Software Foundation.
7 */
8
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.h>
16 #include <net/netfilter/ipv4/nf_dup_ipv4.h>
17
18 struct nft_dup_ipv4 {
19 enum nft_registers sreg_addr:8;
20 enum nft_registers sreg_dev:8;
21 };
22
nft_dup_ipv4_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)23 static void nft_dup_ipv4_eval(const struct nft_expr *expr,
24 struct nft_regs *regs,
25 const struct nft_pktinfo *pkt)
26 {
27 struct nft_dup_ipv4 *priv = nft_expr_priv(expr);
28 struct in_addr gw = {
29 .s_addr = (__force __be32)regs->data[priv->sreg_addr],
30 };
31 int oif = priv->sreg_dev ? regs->data[priv->sreg_dev] : -1;
32
33 nf_dup_ipv4(pkt->net, pkt->skb, pkt->hook, &gw, oif);
34 }
35
nft_dup_ipv4_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])36 static int nft_dup_ipv4_init(const struct nft_ctx *ctx,
37 const struct nft_expr *expr,
38 const struct nlattr * const tb[])
39 {
40 struct nft_dup_ipv4 *priv = nft_expr_priv(expr);
41 int err;
42
43 if (tb[NFTA_DUP_SREG_ADDR] == NULL)
44 return -EINVAL;
45
46 priv->sreg_addr = nft_parse_register(tb[NFTA_DUP_SREG_ADDR]);
47 err = nft_validate_register_load(priv->sreg_addr, sizeof(struct in_addr));
48 if (err < 0)
49 return err;
50
51 if (tb[NFTA_DUP_SREG_DEV] != NULL) {
52 priv->sreg_dev = nft_parse_register(tb[NFTA_DUP_SREG_DEV]);
53 return nft_validate_register_load(priv->sreg_dev, sizeof(int));
54 }
55 return 0;
56 }
57
nft_dup_ipv4_dump(struct sk_buff * skb,const struct nft_expr * expr)58 static int nft_dup_ipv4_dump(struct sk_buff *skb, const struct nft_expr *expr)
59 {
60 struct nft_dup_ipv4 *priv = nft_expr_priv(expr);
61
62 if (nft_dump_register(skb, NFTA_DUP_SREG_ADDR, priv->sreg_addr))
63 goto nla_put_failure;
64 if (priv->sreg_dev &&
65 nft_dump_register(skb, NFTA_DUP_SREG_DEV, priv->sreg_dev))
66 goto nla_put_failure;
67
68 return 0;
69
70 nla_put_failure:
71 return -1;
72 }
73
74 static struct nft_expr_type nft_dup_ipv4_type;
75 static const struct nft_expr_ops nft_dup_ipv4_ops = {
76 .type = &nft_dup_ipv4_type,
77 .size = NFT_EXPR_SIZE(sizeof(struct nft_dup_ipv4)),
78 .eval = nft_dup_ipv4_eval,
79 .init = nft_dup_ipv4_init,
80 .dump = nft_dup_ipv4_dump,
81 };
82
83 static const struct nla_policy nft_dup_ipv4_policy[NFTA_DUP_MAX + 1] = {
84 [NFTA_DUP_SREG_ADDR] = { .type = NLA_U32 },
85 [NFTA_DUP_SREG_DEV] = { .type = NLA_U32 },
86 };
87
88 static struct nft_expr_type nft_dup_ipv4_type __read_mostly = {
89 .family = NFPROTO_IPV4,
90 .name = "dup",
91 .ops = &nft_dup_ipv4_ops,
92 .policy = nft_dup_ipv4_policy,
93 .maxattr = NFTA_DUP_MAX,
94 .owner = THIS_MODULE,
95 };
96
nft_dup_ipv4_module_init(void)97 static int __init nft_dup_ipv4_module_init(void)
98 {
99 return nft_register_expr(&nft_dup_ipv4_type);
100 }
101
nft_dup_ipv4_module_exit(void)102 static void __exit nft_dup_ipv4_module_exit(void)
103 {
104 nft_unregister_expr(&nft_dup_ipv4_type);
105 }
106
107 module_init(nft_dup_ipv4_module_init);
108 module_exit(nft_dup_ipv4_module_exit);
109
110 MODULE_LICENSE("GPL");
111 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
112 MODULE_ALIAS_NFT_AF_EXPR(AF_INET, "dup");
113