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2fa84193 AP |
1 | /* |
2 | * Copyright (c) 2016 Anders K. Pedersen <akp@cohaesio.com> | |
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/dst.h> | |
16 | #include <net/ip6_route.h> | |
17 | #include <net/route.h> | |
18 | #include <net/netfilter/nf_tables.h> | |
19 | #include <net/netfilter/nf_tables_core.h> | |
20 | ||
21 | struct nft_rt { | |
22 | enum nft_rt_keys key:8; | |
23 | enum nft_registers dreg:8; | |
24 | }; | |
25 | ||
26 | void nft_rt_get_eval(const struct nft_expr *expr, | |
27 | struct nft_regs *regs, | |
28 | const struct nft_pktinfo *pkt) | |
29 | { | |
30 | const struct nft_rt *priv = nft_expr_priv(expr); | |
31 | const struct sk_buff *skb = pkt->skb; | |
32 | u32 *dest = ®s->data[priv->dreg]; | |
33 | const struct dst_entry *dst; | |
34 | ||
35 | dst = skb_dst(skb); | |
36 | if (!dst) | |
37 | goto err; | |
38 | ||
39 | switch (priv->key) { | |
40 | #ifdef CONFIG_IP_ROUTE_CLASSID | |
41 | case NFT_RT_CLASSID: | |
42 | *dest = dst->tclassid; | |
43 | break; | |
44 | #endif | |
45 | case NFT_RT_NEXTHOP4: | |
0e5a1c7e | 46 | if (nft_pf(pkt) != NFPROTO_IPV4) |
2fa84193 AP |
47 | goto err; |
48 | ||
49 | *dest = rt_nexthop((const struct rtable *)dst, | |
50 | ip_hdr(skb)->daddr); | |
51 | break; | |
52 | case NFT_RT_NEXTHOP6: | |
0e5a1c7e | 53 | if (nft_pf(pkt) != NFPROTO_IPV6) |
2fa84193 AP |
54 | goto err; |
55 | ||
56 | memcpy(dest, rt6_nexthop((struct rt6_info *)dst, | |
57 | &ipv6_hdr(skb)->daddr), | |
58 | sizeof(struct in6_addr)); | |
59 | break; | |
60 | default: | |
61 | WARN_ON(1); | |
62 | goto err; | |
63 | } | |
64 | return; | |
65 | ||
66 | err: | |
67 | regs->verdict.code = NFT_BREAK; | |
68 | } | |
69 | ||
70 | const struct nla_policy nft_rt_policy[NFTA_RT_MAX + 1] = { | |
71 | [NFTA_RT_DREG] = { .type = NLA_U32 }, | |
72 | [NFTA_RT_KEY] = { .type = NLA_U32 }, | |
73 | }; | |
74 | ||
75 | int nft_rt_get_init(const struct nft_ctx *ctx, | |
76 | const struct nft_expr *expr, | |
77 | const struct nlattr * const tb[]) | |
78 | { | |
79 | struct nft_rt *priv = nft_expr_priv(expr); | |
80 | unsigned int len; | |
81 | ||
82 | if (tb[NFTA_RT_KEY] == NULL || | |
83 | tb[NFTA_RT_DREG] == NULL) | |
84 | return -EINVAL; | |
85 | ||
86 | priv->key = ntohl(nla_get_be32(tb[NFTA_RT_KEY])); | |
87 | switch (priv->key) { | |
88 | #ifdef CONFIG_IP_ROUTE_CLASSID | |
89 | case NFT_RT_CLASSID: | |
90 | #endif | |
91 | case NFT_RT_NEXTHOP4: | |
92 | len = sizeof(u32); | |
93 | break; | |
94 | case NFT_RT_NEXTHOP6: | |
95 | len = sizeof(struct in6_addr); | |
96 | break; | |
97 | default: | |
98 | return -EOPNOTSUPP; | |
99 | } | |
100 | ||
101 | priv->dreg = nft_parse_register(tb[NFTA_RT_DREG]); | |
102 | return nft_validate_register_store(ctx, priv->dreg, NULL, | |
103 | NFT_DATA_VALUE, len); | |
104 | } | |
105 | ||
106 | int nft_rt_get_dump(struct sk_buff *skb, | |
107 | const struct nft_expr *expr) | |
108 | { | |
109 | const struct nft_rt *priv = nft_expr_priv(expr); | |
110 | ||
111 | if (nla_put_be32(skb, NFTA_RT_KEY, htonl(priv->key))) | |
112 | goto nla_put_failure; | |
113 | if (nft_dump_register(skb, NFTA_RT_DREG, priv->dreg)) | |
114 | goto nla_put_failure; | |
115 | return 0; | |
116 | ||
117 | nla_put_failure: | |
118 | return -1; | |
119 | } | |
120 | ||
121 | static struct nft_expr_type nft_rt_type; | |
122 | static const struct nft_expr_ops nft_rt_get_ops = { | |
123 | .type = &nft_rt_type, | |
124 | .size = NFT_EXPR_SIZE(sizeof(struct nft_rt)), | |
125 | .eval = nft_rt_get_eval, | |
126 | .init = nft_rt_get_init, | |
127 | .dump = nft_rt_get_dump, | |
128 | }; | |
129 | ||
130 | static struct nft_expr_type nft_rt_type __read_mostly = { | |
131 | .name = "rt", | |
132 | .ops = &nft_rt_get_ops, | |
133 | .policy = nft_rt_policy, | |
134 | .maxattr = NFTA_RT_MAX, | |
135 | .owner = THIS_MODULE, | |
136 | }; | |
137 | ||
138 | static int __init nft_rt_module_init(void) | |
139 | { | |
140 | return nft_register_expr(&nft_rt_type); | |
141 | } | |
142 | ||
143 | static void __exit nft_rt_module_exit(void) | |
144 | { | |
145 | nft_unregister_expr(&nft_rt_type); | |
146 | } | |
147 | ||
148 | module_init(nft_rt_module_init); | |
149 | module_exit(nft_rt_module_exit); | |
150 | ||
151 | MODULE_LICENSE("GPL"); | |
152 | MODULE_AUTHOR("Anders K. Pedersen <akp@cohaesio.com>"); | |
153 | MODULE_ALIAS_NFT_EXPR("rt"); |