1/*
2 * Copyright (c) 2014 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
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/nft_reject.h>
17#include <net/netfilter/ipv4/nf_reject.h>
18#include <net/netfilter/ipv6/nf_reject.h>
19
20static void nft_reject_inet_eval(const struct nft_expr *expr,
21				 struct nft_regs *regs,
22				 const struct nft_pktinfo *pkt)
23{
24	struct nft_reject *priv = nft_expr_priv(expr);
25
26	switch (pkt->pf) {
27	case NFPROTO_IPV4:
28		switch (priv->type) {
29		case NFT_REJECT_ICMP_UNREACH:
30			nf_send_unreach(pkt->skb, priv->icmp_code,
31					pkt->hook);
32			break;
33		case NFT_REJECT_TCP_RST:
34			nf_send_reset(pkt->net, pkt->skb, pkt->hook);
35			break;
36		case NFT_REJECT_ICMPX_UNREACH:
37			nf_send_unreach(pkt->skb,
38					nft_reject_icmp_code(priv->icmp_code),
39					pkt->hook);
40			break;
41		}
42		break;
43	case NFPROTO_IPV6:
44		switch (priv->type) {
45		case NFT_REJECT_ICMP_UNREACH:
46			nf_send_unreach6(pkt->net, pkt->skb, priv->icmp_code,
47					 pkt->hook);
48			break;
49		case NFT_REJECT_TCP_RST:
50			nf_send_reset6(pkt->net, pkt->skb, pkt->hook);
51			break;
52		case NFT_REJECT_ICMPX_UNREACH:
53			nf_send_unreach6(pkt->net, pkt->skb,
54					 nft_reject_icmpv6_code(priv->icmp_code),
55					 pkt->hook);
56			break;
57		}
58		break;
59	}
60
61	regs->verdict.code = NF_DROP;
62}
63
64static int nft_reject_inet_init(const struct nft_ctx *ctx,
65				const struct nft_expr *expr,
66				const struct nlattr * const tb[])
67{
68	struct nft_reject *priv = nft_expr_priv(expr);
69	int icmp_code;
70
71	if (tb[NFTA_REJECT_TYPE] == NULL)
72		return -EINVAL;
73
74	priv->type = ntohl(nla_get_be32(tb[NFTA_REJECT_TYPE]));
75	switch (priv->type) {
76	case NFT_REJECT_ICMP_UNREACH:
77	case NFT_REJECT_ICMPX_UNREACH:
78		if (tb[NFTA_REJECT_ICMP_CODE] == NULL)
79			return -EINVAL;
80
81		icmp_code = nla_get_u8(tb[NFTA_REJECT_ICMP_CODE]);
82		if (priv->type == NFT_REJECT_ICMPX_UNREACH &&
83		    icmp_code > NFT_REJECT_ICMPX_MAX)
84			return -EINVAL;
85
86		priv->icmp_code = icmp_code;
87		break;
88	case NFT_REJECT_TCP_RST:
89		break;
90	default:
91		return -EINVAL;
92	}
93	return 0;
94}
95
96static int nft_reject_inet_dump(struct sk_buff *skb,
97				const struct nft_expr *expr)
98{
99	const struct nft_reject *priv = nft_expr_priv(expr);
100
101	if (nla_put_be32(skb, NFTA_REJECT_TYPE, htonl(priv->type)))
102		goto nla_put_failure;
103
104	switch (priv->type) {
105	case NFT_REJECT_ICMP_UNREACH:
106	case NFT_REJECT_ICMPX_UNREACH:
107		if (nla_put_u8(skb, NFTA_REJECT_ICMP_CODE, priv->icmp_code))
108			goto nla_put_failure;
109		break;
110	default:
111		break;
112	}
113
114	return 0;
115
116nla_put_failure:
117	return -1;
118}
119
120static struct nft_expr_type nft_reject_inet_type;
121static const struct nft_expr_ops nft_reject_inet_ops = {
122	.type		= &nft_reject_inet_type,
123	.size		= NFT_EXPR_SIZE(sizeof(struct nft_reject)),
124	.eval		= nft_reject_inet_eval,
125	.init		= nft_reject_inet_init,
126	.dump		= nft_reject_inet_dump,
127};
128
129static struct nft_expr_type nft_reject_inet_type __read_mostly = {
130	.family		= NFPROTO_INET,
131	.name		= "reject",
132	.ops		= &nft_reject_inet_ops,
133	.policy		= nft_reject_policy,
134	.maxattr	= NFTA_REJECT_MAX,
135	.owner		= THIS_MODULE,
136};
137
138static int __init nft_reject_inet_module_init(void)
139{
140	return nft_register_expr(&nft_reject_inet_type);
141}
142
143static void __exit nft_reject_inet_module_exit(void)
144{
145	nft_unregister_expr(&nft_reject_inet_type);
146}
147
148module_init(nft_reject_inet_module_init);
149module_exit(nft_reject_inet_module_exit);
150
151MODULE_LICENSE("GPL");
152MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
153MODULE_ALIAS_NFT_AF_EXPR(1, "reject");
154