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1 /* iptables module for using new netfilter netlink queue
2  *
3  * (C) 2005 by Harald Welte <laforge@netfilter.org>
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License version 2 as
7  * published by the Free Software Foundation.
8  *
9  */
10 
11 #include <linux/module.h>
12 #include <linux/skbuff.h>
13 
14 #include <linux/netfilter.h>
15 #include <linux/netfilter_arp.h>
16 #include <linux/netfilter/x_tables.h>
17 #include <linux/netfilter/xt_NFQUEUE.h>
18 
19 #include <net/netfilter/nf_queue.h>
20 
21 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
22 MODULE_DESCRIPTION("Xtables: packet forwarding to netlink");
23 MODULE_LICENSE("GPL");
24 MODULE_ALIAS("ipt_NFQUEUE");
25 MODULE_ALIAS("ip6t_NFQUEUE");
26 MODULE_ALIAS("arpt_NFQUEUE");
27 
28 static u32 jhash_initval __read_mostly;
29 
30 static unsigned int
nfqueue_tg(struct sk_buff * skb,const struct xt_action_param * par)31 nfqueue_tg(struct sk_buff *skb, const struct xt_action_param *par)
32 {
33 	const struct xt_NFQ_info *tinfo = par->targinfo;
34 
35 	return NF_QUEUE_NR(tinfo->queuenum);
36 }
37 
38 static unsigned int
nfqueue_tg_v1(struct sk_buff * skb,const struct xt_action_param * par)39 nfqueue_tg_v1(struct sk_buff *skb, const struct xt_action_param *par)
40 {
41 	const struct xt_NFQ_info_v1 *info = par->targinfo;
42 	u32 queue = info->queuenum;
43 
44 	if (info->queues_total > 1) {
45 		queue = nfqueue_hash(skb, queue, info->queues_total,
46 				     par->family, jhash_initval);
47 	}
48 	return NF_QUEUE_NR(queue);
49 }
50 
51 static unsigned int
nfqueue_tg_v2(struct sk_buff * skb,const struct xt_action_param * par)52 nfqueue_tg_v2(struct sk_buff *skb, const struct xt_action_param *par)
53 {
54 	const struct xt_NFQ_info_v2 *info = par->targinfo;
55 	unsigned int ret = nfqueue_tg_v1(skb, par);
56 
57 	if (info->bypass)
58 		ret |= NF_VERDICT_FLAG_QUEUE_BYPASS;
59 	return ret;
60 }
61 
nfqueue_tg_check(const struct xt_tgchk_param * par)62 static int nfqueue_tg_check(const struct xt_tgchk_param *par)
63 {
64 	const struct xt_NFQ_info_v3 *info = par->targinfo;
65 	u32 maxid;
66 
67 	init_hashrandom(&jhash_initval);
68 
69 	if (info->queues_total == 0) {
70 		pr_err("NFQUEUE: number of total queues is 0\n");
71 		return -EINVAL;
72 	}
73 	maxid = info->queues_total - 1 + info->queuenum;
74 	if (maxid > 0xffff) {
75 		pr_err("NFQUEUE: number of queues (%u) out of range (got %u)\n",
76 		       info->queues_total, maxid);
77 		return -ERANGE;
78 	}
79 	if (par->target->revision == 2 && info->flags > 1)
80 		return -EINVAL;
81 	if (par->target->revision == 3 && info->flags & ~NFQ_FLAG_MASK)
82 		return -EINVAL;
83 
84 	return 0;
85 }
86 
87 static unsigned int
nfqueue_tg_v3(struct sk_buff * skb,const struct xt_action_param * par)88 nfqueue_tg_v3(struct sk_buff *skb, const struct xt_action_param *par)
89 {
90 	const struct xt_NFQ_info_v3 *info = par->targinfo;
91 	u32 queue = info->queuenum;
92 	int ret;
93 
94 	if (info->queues_total > 1) {
95 		if (info->flags & NFQ_FLAG_CPU_FANOUT) {
96 			int cpu = smp_processor_id();
97 
98 			queue = info->queuenum + cpu % info->queues_total;
99 		} else {
100 			queue = nfqueue_hash(skb, queue, info->queues_total,
101 					     par->family, jhash_initval);
102 		}
103 	}
104 
105 	ret = NF_QUEUE_NR(queue);
106 	if (info->flags & NFQ_FLAG_BYPASS)
107 		ret |= NF_VERDICT_FLAG_QUEUE_BYPASS;
108 
109 	return ret;
110 }
111 
112 static struct xt_target nfqueue_tg_reg[] __read_mostly = {
113 	{
114 		.name		= "NFQUEUE",
115 		.family		= NFPROTO_UNSPEC,
116 		.target		= nfqueue_tg,
117 		.targetsize	= sizeof(struct xt_NFQ_info),
118 		.me		= THIS_MODULE,
119 	},
120 	{
121 		.name		= "NFQUEUE",
122 		.revision	= 1,
123 		.family		= NFPROTO_UNSPEC,
124 		.checkentry	= nfqueue_tg_check,
125 		.target		= nfqueue_tg_v1,
126 		.targetsize	= sizeof(struct xt_NFQ_info_v1),
127 		.me		= THIS_MODULE,
128 	},
129 	{
130 		.name		= "NFQUEUE",
131 		.revision	= 2,
132 		.family		= NFPROTO_UNSPEC,
133 		.checkentry	= nfqueue_tg_check,
134 		.target		= nfqueue_tg_v2,
135 		.targetsize	= sizeof(struct xt_NFQ_info_v2),
136 		.me		= THIS_MODULE,
137 	},
138 	{
139 		.name		= "NFQUEUE",
140 		.revision	= 3,
141 		.family		= NFPROTO_UNSPEC,
142 		.checkentry	= nfqueue_tg_check,
143 		.target		= nfqueue_tg_v3,
144 		.targetsize	= sizeof(struct xt_NFQ_info_v3),
145 		.me		= THIS_MODULE,
146 	},
147 };
148 
nfqueue_tg_init(void)149 static int __init nfqueue_tg_init(void)
150 {
151 	return xt_register_targets(nfqueue_tg_reg, ARRAY_SIZE(nfqueue_tg_reg));
152 }
153 
nfqueue_tg_exit(void)154 static void __exit nfqueue_tg_exit(void)
155 {
156 	xt_unregister_targets(nfqueue_tg_reg, ARRAY_SIZE(nfqueue_tg_reg));
157 }
158 
159 module_init(nfqueue_tg_init);
160 module_exit(nfqueue_tg_exit);
161