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/ip.h>
15#include <linux/ipv6.h>
16#include <linux/jhash.h>
17
18#include <linux/netfilter.h>
19#include <linux/netfilter_arp.h>
20#include <linux/netfilter/x_tables.h>
21#include <linux/netfilter/xt_NFQUEUE.h>
22
23MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
24MODULE_DESCRIPTION("Xtables: packet forwarding to netlink");
25MODULE_LICENSE("GPL");
26MODULE_ALIAS("ipt_NFQUEUE");
27MODULE_ALIAS("ip6t_NFQUEUE");
28MODULE_ALIAS("arpt_NFQUEUE");
29
30static u32 jhash_initval __read_mostly;
31static bool rnd_inited __read_mostly;
32
33static unsigned int
34nfqueue_tg(struct sk_buff *skb, const struct xt_action_param *par)
35{
36	const struct xt_NFQ_info *tinfo = par->targinfo;
37
38	return NF_QUEUE_NR(tinfo->queuenum);
39}
40
41static u32 hash_v4(const struct sk_buff *skb)
42{
43	const struct iphdr *iph = ip_hdr(skb);
44
45	/* packets in either direction go into same queue */
46	if ((__force u32)iph->saddr < (__force u32)iph->daddr)
47		return jhash_3words((__force u32)iph->saddr,
48			(__force u32)iph->daddr, iph->protocol, jhash_initval);
49
50	return jhash_3words((__force u32)iph->daddr,
51			(__force u32)iph->saddr, iph->protocol, jhash_initval);
52}
53
54#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
55static u32 hash_v6(const struct sk_buff *skb)
56{
57	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
58	u32 a, b, c;
59
60	if ((__force u32)ip6h->saddr.s6_addr32[3] <
61	    (__force u32)ip6h->daddr.s6_addr32[3]) {
62		a = (__force u32) ip6h->saddr.s6_addr32[3];
63		b = (__force u32) ip6h->daddr.s6_addr32[3];
64	} else {
65		b = (__force u32) ip6h->saddr.s6_addr32[3];
66		a = (__force u32) ip6h->daddr.s6_addr32[3];
67	}
68
69	if ((__force u32)ip6h->saddr.s6_addr32[1] <
70	    (__force u32)ip6h->daddr.s6_addr32[1])
71		c = (__force u32) ip6h->saddr.s6_addr32[1];
72	else
73		c = (__force u32) ip6h->daddr.s6_addr32[1];
74
75	return jhash_3words(a, b, c, jhash_initval);
76}
77#endif
78
79static u32
80nfqueue_hash(const struct sk_buff *skb, const struct xt_action_param *par)
81{
82	const struct xt_NFQ_info_v1 *info = par->targinfo;
83	u32 queue = info->queuenum;
84
85	if (par->family == NFPROTO_IPV4)
86		queue += ((u64) hash_v4(skb) * info->queues_total) >> 32;
87#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
88	else if (par->family == NFPROTO_IPV6)
89		queue += ((u64) hash_v6(skb) * info->queues_total) >> 32;
90#endif
91
92	return queue;
93}
94
95static unsigned int
96nfqueue_tg_v1(struct sk_buff *skb, const struct xt_action_param *par)
97{
98	const struct xt_NFQ_info_v1 *info = par->targinfo;
99	u32 queue = info->queuenum;
100
101	if (info->queues_total > 1)
102		queue = nfqueue_hash(skb, par);
103
104	return NF_QUEUE_NR(queue);
105}
106
107static unsigned int
108nfqueue_tg_v2(struct sk_buff *skb, const struct xt_action_param *par)
109{
110	const struct xt_NFQ_info_v2 *info = par->targinfo;
111	unsigned int ret = nfqueue_tg_v1(skb, par);
112
113	if (info->bypass)
114		ret |= NF_VERDICT_FLAG_QUEUE_BYPASS;
115	return ret;
116}
117
118static int nfqueue_tg_check(const struct xt_tgchk_param *par)
119{
120	const struct xt_NFQ_info_v3 *info = par->targinfo;
121	u32 maxid;
122
123	if (unlikely(!rnd_inited)) {
124		get_random_bytes(&jhash_initval, sizeof(jhash_initval));
125		rnd_inited = true;
126	}
127	if (info->queues_total == 0) {
128		pr_err("NFQUEUE: number of total queues is 0\n");
129		return -EINVAL;
130	}
131	maxid = info->queues_total - 1 + info->queuenum;
132	if (maxid > 0xffff) {
133		pr_err("NFQUEUE: number of queues (%u) out of range (got %u)\n",
134		       info->queues_total, maxid);
135		return -ERANGE;
136	}
137	if (par->target->revision == 2 && info->flags > 1)
138		return -EINVAL;
139	if (par->target->revision == 3 && info->flags & ~NFQ_FLAG_MASK)
140		return -EINVAL;
141
142	return 0;
143}
144
145static unsigned int
146nfqueue_tg_v3(struct sk_buff *skb, const struct xt_action_param *par)
147{
148	const struct xt_NFQ_info_v3 *info = par->targinfo;
149	u32 queue = info->queuenum;
150
151	if (info->queues_total > 1) {
152		if (info->flags & NFQ_FLAG_CPU_FANOUT) {
153			int cpu = smp_processor_id();
154
155			queue = info->queuenum + cpu % info->queues_total;
156		} else
157			queue = nfqueue_hash(skb, par);
158	}
159
160	return NF_QUEUE_NR(queue);
161}
162
163static struct xt_target nfqueue_tg_reg[] __read_mostly = {
164	{
165		.name		= "NFQUEUE",
166		.family		= NFPROTO_UNSPEC,
167		.target		= nfqueue_tg,
168		.targetsize	= sizeof(struct xt_NFQ_info),
169		.me		= THIS_MODULE,
170	},
171	{
172		.name		= "NFQUEUE",
173		.revision	= 1,
174		.family		= NFPROTO_UNSPEC,
175		.checkentry	= nfqueue_tg_check,
176		.target		= nfqueue_tg_v1,
177		.targetsize	= sizeof(struct xt_NFQ_info_v1),
178		.me		= THIS_MODULE,
179	},
180	{
181		.name		= "NFQUEUE",
182		.revision	= 2,
183		.family		= NFPROTO_UNSPEC,
184		.checkentry	= nfqueue_tg_check,
185		.target		= nfqueue_tg_v2,
186		.targetsize	= sizeof(struct xt_NFQ_info_v2),
187		.me		= THIS_MODULE,
188	},
189	{
190		.name		= "NFQUEUE",
191		.revision	= 3,
192		.family		= NFPROTO_UNSPEC,
193		.checkentry	= nfqueue_tg_check,
194		.target		= nfqueue_tg_v3,
195		.targetsize	= sizeof(struct xt_NFQ_info_v3),
196		.me		= THIS_MODULE,
197	},
198};
199
200static int __init nfqueue_tg_init(void)
201{
202	return xt_register_targets(nfqueue_tg_reg, ARRAY_SIZE(nfqueue_tg_reg));
203}
204
205static void __exit nfqueue_tg_exit(void)
206{
207	xt_unregister_targets(nfqueue_tg_reg, ARRAY_SIZE(nfqueue_tg_reg));
208}
209
210module_init(nfqueue_tg_init);
211module_exit(nfqueue_tg_exit);
212