mqprio: Avoid panic if no options are provided
[linux-2.6.git] / net / netfilter / xt_ipvs.c
1 /*
2  *      xt_ipvs - kernel module to match IPVS connection properties
3  *
4  *      Author: Hannes Eder <heder@google.com>
5  */
6
7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9 #include <linux/module.h>
10 #include <linux/moduleparam.h>
11 #include <linux/spinlock.h>
12 #include <linux/skbuff.h>
13 #ifdef CONFIG_IP_VS_IPV6
14 #include <net/ipv6.h>
15 #endif
16 #include <linux/ip_vs.h>
17 #include <linux/types.h>
18 #include <linux/netfilter/x_tables.h>
19 #include <linux/netfilter/xt_ipvs.h>
20 #include <net/netfilter/nf_conntrack.h>
21
22 #include <net/ip_vs.h>
23
24 MODULE_AUTHOR("Hannes Eder <heder@google.com>");
25 MODULE_DESCRIPTION("Xtables: match IPVS connection properties");
26 MODULE_LICENSE("GPL");
27 MODULE_ALIAS("ipt_ipvs");
28 MODULE_ALIAS("ip6t_ipvs");
29
30 /* borrowed from xt_conntrack */
31 static bool ipvs_mt_addrcmp(const union nf_inet_addr *kaddr,
32                             const union nf_inet_addr *uaddr,
33                             const union nf_inet_addr *umask,
34                             unsigned int l3proto)
35 {
36         if (l3proto == NFPROTO_IPV4)
37                 return ((kaddr->ip ^ uaddr->ip) & umask->ip) == 0;
38 #ifdef CONFIG_IP_VS_IPV6
39         else if (l3proto == NFPROTO_IPV6)
40                 return ipv6_masked_addr_cmp(&kaddr->in6, &umask->in6,
41                        &uaddr->in6) == 0;
42 #endif
43         else
44                 return false;
45 }
46
47 static bool
48 ipvs_mt(const struct sk_buff *skb, struct xt_action_param *par)
49 {
50         const struct xt_ipvs_mtinfo *data = par->matchinfo;
51         /* ipvs_mt_check ensures that family is only NFPROTO_IPV[46]. */
52         const u_int8_t family = par->family;
53         struct ip_vs_iphdr iph;
54         struct ip_vs_protocol *pp;
55         struct ip_vs_conn *cp;
56         bool match = true;
57
58         if (data->bitmask == XT_IPVS_IPVS_PROPERTY) {
59                 match = skb->ipvs_property ^
60                         !!(data->invert & XT_IPVS_IPVS_PROPERTY);
61                 goto out;
62         }
63
64         /* other flags than XT_IPVS_IPVS_PROPERTY are set */
65         if (!skb->ipvs_property) {
66                 match = false;
67                 goto out;
68         }
69
70         ip_vs_fill_iphdr(family, skb_network_header(skb), &iph);
71
72         if (data->bitmask & XT_IPVS_PROTO)
73                 if ((iph.protocol == data->l4proto) ^
74                     !(data->invert & XT_IPVS_PROTO)) {
75                         match = false;
76                         goto out;
77                 }
78
79         pp = ip_vs_proto_get(iph.protocol);
80         if (unlikely(!pp)) {
81                 match = false;
82                 goto out;
83         }
84
85         /*
86          * Check if the packet belongs to an existing entry
87          */
88         cp = pp->conn_out_get(family, skb, &iph, iph.len, 1 /* inverse */);
89         if (unlikely(cp == NULL)) {
90                 match = false;
91                 goto out;
92         }
93
94         /*
95          * We found a connection, i.e. ct != 0, make sure to call
96          * __ip_vs_conn_put before returning.  In our case jump to out_put_con.
97          */
98
99         if (data->bitmask & XT_IPVS_VPORT)
100                 if ((cp->vport == data->vport) ^
101                     !(data->invert & XT_IPVS_VPORT)) {
102                         match = false;
103                         goto out_put_cp;
104                 }
105
106         if (data->bitmask & XT_IPVS_VPORTCTL)
107                 if ((cp->control != NULL &&
108                      cp->control->vport == data->vportctl) ^
109                     !(data->invert & XT_IPVS_VPORTCTL)) {
110                         match = false;
111                         goto out_put_cp;
112                 }
113
114         if (data->bitmask & XT_IPVS_DIR) {
115                 enum ip_conntrack_info ctinfo;
116                 struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
117
118                 if (ct == NULL || nf_ct_is_untracked(ct)) {
119                         match = false;
120                         goto out_put_cp;
121                 }
122
123                 if ((ctinfo >= IP_CT_IS_REPLY) ^
124                     !!(data->invert & XT_IPVS_DIR)) {
125                         match = false;
126                         goto out_put_cp;
127                 }
128         }
129
130         if (data->bitmask & XT_IPVS_METHOD)
131                 if (((cp->flags & IP_VS_CONN_F_FWD_MASK) == data->fwd_method) ^
132                     !(data->invert & XT_IPVS_METHOD)) {
133                         match = false;
134                         goto out_put_cp;
135                 }
136
137         if (data->bitmask & XT_IPVS_VADDR) {
138                 if (ipvs_mt_addrcmp(&cp->vaddr, &data->vaddr,
139                                     &data->vmask, family) ^
140                     !(data->invert & XT_IPVS_VADDR)) {
141                         match = false;
142                         goto out_put_cp;
143                 }
144         }
145
146 out_put_cp:
147         __ip_vs_conn_put(cp);
148 out:
149         pr_debug("match=%d\n", match);
150         return match;
151 }
152
153 static int ipvs_mt_check(const struct xt_mtchk_param *par)
154 {
155         if (par->family != NFPROTO_IPV4
156 #ifdef CONFIG_IP_VS_IPV6
157             && par->family != NFPROTO_IPV6
158 #endif
159                 ) {
160                 pr_info("protocol family %u not supported\n", par->family);
161                 return -EINVAL;
162         }
163
164         return 0;
165 }
166
167 static struct xt_match xt_ipvs_mt_reg __read_mostly = {
168         .name       = "ipvs",
169         .revision   = 0,
170         .family     = NFPROTO_UNSPEC,
171         .match      = ipvs_mt,
172         .checkentry = ipvs_mt_check,
173         .matchsize  = XT_ALIGN(sizeof(struct xt_ipvs_mtinfo)),
174         .me         = THIS_MODULE,
175 };
176
177 static int __init ipvs_mt_init(void)
178 {
179         return xt_register_match(&xt_ipvs_mt_reg);
180 }
181
182 static void __exit ipvs_mt_exit(void)
183 {
184         xt_unregister_match(&xt_ipvs_mt_reg);
185 }
186
187 module_init(ipvs_mt_init);
188 module_exit(ipvs_mt_exit);