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_regs * regs,const struct nft_pktinfo * pkt)20 static 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
nft_reject_inet_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])64 static 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, err;
70
71 err = nft_reject_validate(ctx, expr, NULL);
72 if (err < 0)
73 return err;
74
75 if (tb[NFTA_REJECT_TYPE] == NULL)
76 return -EINVAL;
77
78 priv->type = ntohl(nla_get_be32(tb[NFTA_REJECT_TYPE]));
79 switch (priv->type) {
80 case NFT_REJECT_ICMP_UNREACH:
81 case NFT_REJECT_ICMPX_UNREACH:
82 if (tb[NFTA_REJECT_ICMP_CODE] == NULL)
83 return -EINVAL;
84
85 icmp_code = nla_get_u8(tb[NFTA_REJECT_ICMP_CODE]);
86 if (priv->type == NFT_REJECT_ICMPX_UNREACH &&
87 icmp_code > NFT_REJECT_ICMPX_MAX)
88 return -EINVAL;
89
90 priv->icmp_code = icmp_code;
91 break;
92 case NFT_REJECT_TCP_RST:
93 break;
94 default:
95 return -EINVAL;
96 }
97 return 0;
98 }
99
nft_reject_inet_dump(struct sk_buff * skb,const struct nft_expr * expr)100 static int nft_reject_inet_dump(struct sk_buff *skb,
101 const struct nft_expr *expr)
102 {
103 const struct nft_reject *priv = nft_expr_priv(expr);
104
105 if (nla_put_be32(skb, NFTA_REJECT_TYPE, htonl(priv->type)))
106 goto nla_put_failure;
107
108 switch (priv->type) {
109 case NFT_REJECT_ICMP_UNREACH:
110 case NFT_REJECT_ICMPX_UNREACH:
111 if (nla_put_u8(skb, NFTA_REJECT_ICMP_CODE, priv->icmp_code))
112 goto nla_put_failure;
113 break;
114 default:
115 break;
116 }
117
118 return 0;
119
120 nla_put_failure:
121 return -1;
122 }
123
124 static struct nft_expr_type nft_reject_inet_type;
125 static const struct nft_expr_ops nft_reject_inet_ops = {
126 .type = &nft_reject_inet_type,
127 .size = NFT_EXPR_SIZE(sizeof(struct nft_reject)),
128 .eval = nft_reject_inet_eval,
129 .init = nft_reject_inet_init,
130 .dump = nft_reject_inet_dump,
131 .validate = nft_reject_validate,
132 };
133
134 static struct nft_expr_type nft_reject_inet_type __read_mostly = {
135 .family = NFPROTO_INET,
136 .name = "reject",
137 .ops = &nft_reject_inet_ops,
138 .policy = nft_reject_policy,
139 .maxattr = NFTA_REJECT_MAX,
140 .owner = THIS_MODULE,
141 };
142
nft_reject_inet_module_init(void)143 static int __init nft_reject_inet_module_init(void)
144 {
145 return nft_register_expr(&nft_reject_inet_type);
146 }
147
nft_reject_inet_module_exit(void)148 static void __exit nft_reject_inet_module_exit(void)
149 {
150 nft_unregister_expr(&nft_reject_inet_type);
151 }
152
153 module_init(nft_reject_inet_module_init);
154 module_exit(nft_reject_inet_module_exit);
155
156 MODULE_LICENSE("GPL");
157 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
158 MODULE_ALIAS_NFT_AF_EXPR(1, "reject");
159