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