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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * xt_ipvs - kernel module to match IPVS connection properties
4 *
5 * Author: Hannes Eder <[email protected]>
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/module.h>
11#include <linux/moduleparam.h>
12#include <linux/spinlock.h>
13#include <linux/skbuff.h>
14#ifdef CONFIG_IP_VS_IPV6
15#include <net/ipv6.h>
16#endif
17#include <linux/ip_vs.h>
18#include <linux/types.h>
19#include <linux/netfilter/x_tables.h>
20#include <linux/netfilter/xt_ipvs.h>
21#include <net/netfilter/nf_conntrack.h>
22
23#include <net/ip_vs.h>
24
25MODULE_AUTHOR("Hannes Eder <[email protected]>");
26MODULE_DESCRIPTION("Xtables: match IPVS connection properties");
27MODULE_LICENSE("GPL");
28MODULE_ALIAS("ipt_ipvs");
29MODULE_ALIAS("ip6t_ipvs");
30
31/* borrowed from xt_conntrack */
32static bool ipvs_mt_addrcmp(const union nf_inet_addr *kaddr,
33 const union nf_inet_addr *uaddr,
34 const union nf_inet_addr *umask,
35 unsigned int l3proto)
36{
37 if (l3proto == NFPROTO_IPV4)
38 return ((kaddr->ip ^ uaddr->ip) & umask->ip) == 0;
39#ifdef CONFIG_IP_VS_IPV6
40 else if (l3proto == NFPROTO_IPV6)
41 return ipv6_masked_addr_cmp(&kaddr->in6, &umask->in6,
42 &uaddr->in6) == 0;
43#endif
44 else
45 return false;
46}
47
48static bool
49ipvs_mt(const struct sk_buff *skb, struct xt_action_param *par)
50{
51 const struct xt_ipvs_mtinfo *data = par->matchinfo;
52 struct netns_ipvs *ipvs = net_ipvs(xt_net(par));
53 /* ipvs_mt_check ensures that family is only NFPROTO_IPV[46]. */
54 const u_int8_t family = xt_family(par);
55 struct ip_vs_iphdr iph;
56 struct ip_vs_protocol *pp;
57 struct ip_vs_conn *cp;
58 bool match = true;
59
60 if (data->bitmask == XT_IPVS_IPVS_PROPERTY) {
61 match = skb->ipvs_property ^
62 !!(data->invert & XT_IPVS_IPVS_PROPERTY);
63 goto out;
64 }
65
66 /* other flags than XT_IPVS_IPVS_PROPERTY are set */
67 if (!skb->ipvs_property) {
68 match = false;
69 goto out;
70 }
71
72 ip_vs_fill_iph_skb(family, skb, true, &iph);
73
74 if (data->bitmask & XT_IPVS_PROTO)
75 if ((iph.protocol == data->l4proto) ^
76 !(data->invert & XT_IPVS_PROTO)) {
77 match = false;
78 goto out;
79 }
80
81 pp = ip_vs_proto_get(iph.protocol);
82 if (unlikely(!pp)) {
83 match = false;
84 goto out;
85 }
86
87 /*
88 * Check if the packet belongs to an existing entry
89 */
90 cp = pp->conn_out_get(ipvs, family, skb, &iph);
91 if (unlikely(cp == NULL)) {
92 match = false;
93 goto out;
94 }
95
96 /*
97 * We found a connection, i.e. ct != 0, make sure to call
98 * __ip_vs_conn_put before returning. In our case jump to out_put_con.
99 */
100
101 if (data->bitmask & XT_IPVS_VPORT)
102 if ((cp->vport == data->vport) ^
103 !(data->invert & XT_IPVS_VPORT)) {
104 match = false;
105 goto out_put_cp;
106 }
107
108 if (data->bitmask & XT_IPVS_VPORTCTL)
109 if ((cp->control != NULL &&
110 cp->control->vport == data->vportctl) ^
111 !(data->invert & XT_IPVS_VPORTCTL)) {
112 match = false;
113 goto out_put_cp;
114 }
115
116 if (data->bitmask & XT_IPVS_DIR) {
117 enum ip_conntrack_info ctinfo;
118 struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
119
120 if (ct == NULL) {
121 match = false;
122 goto out_put_cp;
123 }
124
125 if ((ctinfo >= IP_CT_IS_REPLY) ^
126 !!(data->invert & XT_IPVS_DIR)) {
127 match = false;
128 goto out_put_cp;
129 }
130 }
131
132 if (data->bitmask & XT_IPVS_METHOD)
133 if (((cp->flags & IP_VS_CONN_F_FWD_MASK) == data->fwd_method) ^
134 !(data->invert & XT_IPVS_METHOD)) {
135 match = false;
136 goto out_put_cp;
137 }
138
139 if (data->bitmask & XT_IPVS_VADDR) {
140 if (ipvs_mt_addrcmp(&cp->vaddr, &data->vaddr,
141 &data->vmask, family) ^
142 !(data->invert & XT_IPVS_VADDR)) {
143 match = false;
144 goto out_put_cp;
145 }
146 }
147
148out_put_cp:
149 __ip_vs_conn_put(cp);
150out:
151 return match;
152}
153
154static int ipvs_mt_check(const struct xt_mtchk_param *par)
155{
156 if (par->family != NFPROTO_IPV4
157#ifdef CONFIG_IP_VS_IPV6
158 && par->family != NFPROTO_IPV6
159#endif
160 ) {
161 pr_info_ratelimited("protocol family %u not supported\n",
162 par->family);
163 return -EINVAL;
164 }
165
166 return 0;
167}
168
169static struct xt_match xt_ipvs_mt_reg __read_mostly = {
170 .name = "ipvs",
171 .revision = 0,
172 .family = NFPROTO_UNSPEC,
173 .match = ipvs_mt,
174 .checkentry = ipvs_mt_check,
175 .matchsize = XT_ALIGN(sizeof(struct xt_ipvs_mtinfo)),
176 .me = THIS_MODULE,
177};
178
179static int __init ipvs_mt_init(void)
180{
181 return xt_register_match(&xt_ipvs_mt_reg);
182}
183
184static void __exit ipvs_mt_exit(void)
185{
186 xt_unregister_match(&xt_ipvs_mt_reg);
187}
188
189module_init(ipvs_mt_init);
190module_exit(ipvs_mt_exit);