Hannes Eder | 9c3e1c3 | 2010-07-23 12:42:58 +0200 | [diff] [blame] | 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> |
Hannes Eder | 9c3e1c3 | 2010-07-23 12:42:58 +0200 | [diff] [blame] | 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 | */ |
Hans Schillstrom | 9330419 | 2011-01-03 14:44:51 +0100 | [diff] [blame] | 88 | cp = pp->conn_out_get(family, skb, &iph, iph.len, 1 /* inverse */); |
Hannes Eder | 9c3e1c3 | 2010-07-23 12:42:58 +0200 | [diff] [blame] | 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); |