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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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 | /* * 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(xt_net(par)); /* ipvs_mt_check ensures that family is only NFPROTO_IPV[46]. */ const u_int8_t family = xt_family(par); 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) { 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_ratelimited("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); |