summaryrefslogtreecommitdiff
path: root/net/netfilter/xt_ipvs.c
blob: 71a9d95e0a81bbdd17d94f37c15cf612c1781dd4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
/*
 *	xt_ipvs - kernel module to match IPVS connection properties
 *
 *	Author: Hannes Eder <heder@google.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/spinlock.h>
#include <linux/skbuff.h>
#ifdef CONFIG_IP_VS_IPV6
#include <net/ipv6.h>
#endif
#include <linux/ip_vs.h>
#include <linux/types.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_ipvs.h>
#include <net/netfilter/nf_conntrack.h>

#include <net/ip_vs.h>

MODULE_AUTHOR("Hannes Eder <heder@google.com>");
MODULE_DESCRIPTION("Xtables: match IPVS connection properties");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_ipvs");
MODULE_ALIAS("ip6t_ipvs");

/* borrowed from xt_conntrack */
static bool ipvs_mt_addrcmp(const union nf_inet_addr *kaddr,
			    const union nf_inet_addr *uaddr,
			    const union nf_inet_addr *umask,
			    unsigned int l3proto)
{
	if (l3proto == NFPROTO_IPV4)
		return ((kaddr->ip ^ uaddr->ip) & umask->ip) == 0;
#ifdef CONFIG_IP_VS_IPV6
	else if (l3proto == NFPROTO_IPV6)
		return ipv6_masked_addr_cmp(&kaddr->in6, &umask->in6,
		       &uaddr->in6) == 0;
#endif
	else
		return false;
}

static bool
ipvs_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
	const struct xt_ipvs_mtinfo *data = par->matchinfo;
	struct netns_ipvs *ipvs = net_ipvs(par->net);
	/* ipvs_mt_check ensures that family is only NFPROTO_IPV[46]. */
	const u_int8_t family = par->family;
	struct ip_vs_iphdr iph;
	struct ip_vs_protocol *pp;
	struct ip_vs_conn *cp;
	bool match = true;

	if (data->bitmask == XT_IPVS_IPVS_PROPERTY) {
		match = skb->ipvs_property ^
			!!(data->invert & XT_IPVS_IPVS_PROPERTY);
		goto out;
	}

	/* other flags than XT_IPVS_IPVS_PROPERTY are set */
	if (!skb->ipvs_property) {
		match = false;
		goto out;
	}

	ip_vs_fill_iph_skb(family, skb, true, &iph);

	if (data->bitmask & XT_IPVS_PROTO)
		if ((iph.protocol == data->l4proto) ^
		    !(data->invert & XT_IPVS_PROTO)) {
			match = false;
			goto out;
		}

	pp = ip_vs_proto_get(iph.protocol);
	if (unlikely(!pp)) {
		match = false;
		goto out;
	}

	/*
	 * Check if the packet belongs to an existing entry
	 */
	cp = pp->conn_out_get(ipvs, family, skb, &iph);
	if (unlikely(cp == NULL)) {
		match = false;
		goto out;
	}

	/*
	 * We found a connection, i.e. ct != 0, make sure to call
	 * __ip_vs_conn_put before returning.  In our case jump to out_put_con.
	 */

	if (data->bitmask & XT_IPVS_VPORT)
		if ((cp->vport == data->vport) ^
		    !(data->invert & XT_IPVS_VPORT)) {
			match = false;
			goto out_put_cp;
		}

	if (data->bitmask & XT_IPVS_VPORTCTL)
		if ((cp->control != NULL &&
		     cp->control->vport == data->vportctl) ^
		    !(data->invert & XT_IPVS_VPORTCTL)) {
			match = false;
			goto out_put_cp;
		}

	if (data->bitmask & XT_IPVS_DIR) {
		enum ip_conntrack_info ctinfo;
		struct nf_conn *ct = nf_ct_get(skb, &ctinfo);

		if (ct == NULL || nf_ct_is_untracked(ct)) {
			match = false;
			goto out_put_cp;
		}

		if ((ctinfo >= IP_CT_IS_REPLY) ^
		    !!(data->invert & XT_IPVS_DIR)) {
			match = false;
			goto out_put_cp;
		}
	}

	if (data->bitmask & XT_IPVS_METHOD)
		if (((cp->flags & IP_VS_CONN_F_FWD_MASK) == data->fwd_method) ^
		    !(data->invert & XT_IPVS_METHOD)) {
			match = false;
			goto out_put_cp;
		}

	if (data->bitmask & XT_IPVS_VADDR) {
		if (ipvs_mt_addrcmp(&cp->vaddr, &data->vaddr,
				    &data->vmask, family) ^
		    !(data->invert & XT_IPVS_VADDR)) {
			match = false;
			goto out_put_cp;
		}
	}

out_put_cp:
	__ip_vs_conn_put(cp);
out:
	pr_debug("match=%d\n", match);
	return match;
}

static int ipvs_mt_check(const struct xt_mtchk_param *par)
{
	if (par->family != NFPROTO_IPV4
#ifdef CONFIG_IP_VS_IPV6
	    && par->family != NFPROTO_IPV6
#endif
		) {
		pr_info("protocol family %u not supported\n", par->family);
		return -EINVAL;
	}

	return 0;
}

static struct xt_match xt_ipvs_mt_reg __read_mostly = {
	.name       = "ipvs",
	.revision   = 0,
	.family     = NFPROTO_UNSPEC,
	.match      = ipvs_mt,
	.checkentry = ipvs_mt_check,
	.matchsize  = XT_ALIGN(sizeof(struct xt_ipvs_mtinfo)),
	.me         = THIS_MODULE,
};

static int __init ipvs_mt_init(void)
{
	return xt_register_match(&xt_ipvs_mt_reg);
}

static void __exit ipvs_mt_exit(void)
{
	xt_unregister_match(&xt_ipvs_mt_reg);
}

module_init(ipvs_mt_init);
module_exit(ipvs_mt_exit);