1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | #include <linux/kernel.h> |
3 | #include <linux/init.h> |
4 | #include <linux/module.h> |
5 | #include <linux/netlink.h> |
6 | #include <linux/netfilter.h> |
7 | #include <linux/netfilter/nf_tables.h> |
8 | #include <net/netfilter/nf_tables_core.h> |
9 | #include <net/netfilter/nf_tables.h> |
10 | |
11 | struct nft_last { |
12 | unsigned long jiffies; |
13 | unsigned int set; |
14 | }; |
15 | |
16 | struct nft_last_priv { |
17 | struct nft_last *last; |
18 | }; |
19 | |
20 | static const struct nla_policy nft_last_policy[NFTA_LAST_MAX + 1] = { |
21 | [NFTA_LAST_SET] = { .type = NLA_U32 }, |
22 | [NFTA_LAST_MSECS] = { .type = NLA_U64 }, |
23 | }; |
24 | |
25 | static int nft_last_init(const struct nft_ctx *ctx, const struct nft_expr *expr, |
26 | const struct nlattr * const tb[]) |
27 | { |
28 | struct nft_last_priv *priv = nft_expr_priv(expr); |
29 | struct nft_last *last; |
30 | u64 last_jiffies; |
31 | int err; |
32 | |
33 | last = kzalloc(size: sizeof(*last), GFP_KERNEL_ACCOUNT); |
34 | if (!last) |
35 | return -ENOMEM; |
36 | |
37 | if (tb[NFTA_LAST_SET]) |
38 | last->set = ntohl(nla_get_be32(tb[NFTA_LAST_SET])); |
39 | |
40 | if (last->set && tb[NFTA_LAST_MSECS]) { |
41 | err = nf_msecs_to_jiffies64(nla: tb[NFTA_LAST_MSECS], result: &last_jiffies); |
42 | if (err < 0) |
43 | goto err; |
44 | |
45 | last->jiffies = jiffies - (unsigned long)last_jiffies; |
46 | } |
47 | priv->last = last; |
48 | |
49 | return 0; |
50 | err: |
51 | kfree(objp: last); |
52 | |
53 | return err; |
54 | } |
55 | |
56 | static void nft_last_eval(const struct nft_expr *expr, |
57 | struct nft_regs *regs, const struct nft_pktinfo *pkt) |
58 | { |
59 | struct nft_last_priv *priv = nft_expr_priv(expr); |
60 | struct nft_last *last = priv->last; |
61 | |
62 | if (READ_ONCE(last->jiffies) != jiffies) |
63 | WRITE_ONCE(last->jiffies, jiffies); |
64 | if (READ_ONCE(last->set) == 0) |
65 | WRITE_ONCE(last->set, 1); |
66 | } |
67 | |
68 | static int nft_last_dump(struct sk_buff *skb, |
69 | const struct nft_expr *expr, bool reset) |
70 | { |
71 | struct nft_last_priv *priv = nft_expr_priv(expr); |
72 | struct nft_last *last = priv->last; |
73 | unsigned long last_jiffies = READ_ONCE(last->jiffies); |
74 | u32 last_set = READ_ONCE(last->set); |
75 | __be64 msecs; |
76 | |
77 | if (time_before(jiffies, last_jiffies)) { |
78 | WRITE_ONCE(last->set, 0); |
79 | last_set = 0; |
80 | } |
81 | |
82 | if (last_set) |
83 | msecs = nf_jiffies64_to_msecs(input: jiffies - last_jiffies); |
84 | else |
85 | msecs = 0; |
86 | |
87 | if (nla_put_be32(skb, attrtype: NFTA_LAST_SET, htonl(last_set)) || |
88 | nla_put_be64(skb, attrtype: NFTA_LAST_MSECS, value: msecs, padattr: NFTA_LAST_PAD)) |
89 | goto nla_put_failure; |
90 | |
91 | return 0; |
92 | |
93 | nla_put_failure: |
94 | return -1; |
95 | } |
96 | |
97 | static void nft_last_destroy(const struct nft_ctx *ctx, |
98 | const struct nft_expr *expr) |
99 | { |
100 | struct nft_last_priv *priv = nft_expr_priv(expr); |
101 | |
102 | kfree(objp: priv->last); |
103 | } |
104 | |
105 | static int nft_last_clone(struct nft_expr *dst, const struct nft_expr *src) |
106 | { |
107 | struct nft_last_priv *priv_dst = nft_expr_priv(expr: dst); |
108 | struct nft_last_priv *priv_src = nft_expr_priv(expr: src); |
109 | |
110 | priv_dst->last = kzalloc(size: sizeof(*priv_dst->last), GFP_ATOMIC); |
111 | if (!priv_dst->last) |
112 | return -ENOMEM; |
113 | |
114 | priv_dst->last->set = priv_src->last->set; |
115 | priv_dst->last->jiffies = priv_src->last->jiffies; |
116 | |
117 | return 0; |
118 | } |
119 | |
120 | static const struct nft_expr_ops nft_last_ops = { |
121 | .type = &nft_last_type, |
122 | .size = NFT_EXPR_SIZE(sizeof(struct nft_last_priv)), |
123 | .eval = nft_last_eval, |
124 | .init = nft_last_init, |
125 | .destroy = nft_last_destroy, |
126 | .clone = nft_last_clone, |
127 | .dump = nft_last_dump, |
128 | .reduce = NFT_REDUCE_READONLY, |
129 | }; |
130 | |
131 | struct nft_expr_type nft_last_type __read_mostly = { |
132 | .name = "last" , |
133 | .ops = &nft_last_ops, |
134 | .policy = nft_last_policy, |
135 | .maxattr = NFTA_LAST_MAX, |
136 | .flags = NFT_EXPR_STATEFUL, |
137 | .owner = THIS_MODULE, |
138 | }; |
139 | |