1 /* 2 * (C) 2013 Astaro GmbH & Co KG 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 */ 8 9 #include <linux/module.h> 10 #include <linux/skbuff.h> 11 #include <net/netfilter/nf_conntrack.h> 12 #include <net/netfilter/nf_conntrack_ecache.h> 13 #include <net/netfilter/nf_conntrack_labels.h> 14 #include <linux/netfilter/x_tables.h> 15 16 MODULE_LICENSE("GPL"); 17 MODULE_AUTHOR("Florian Westphal <fw@strlen.de>"); 18 MODULE_DESCRIPTION("Xtables: add/match connection trackling labels"); 19 MODULE_ALIAS("ipt_connlabel"); 20 MODULE_ALIAS("ip6t_connlabel"); 21 22 static bool 23 connlabel_mt(const struct sk_buff *skb, struct xt_action_param *par) 24 { 25 const struct xt_connlabel_mtinfo *info = par->matchinfo; 26 enum ip_conntrack_info ctinfo; 27 struct nf_conn_labels *labels; 28 struct nf_conn *ct; 29 bool invert = info->options & XT_CONNLABEL_OP_INVERT; 30 31 ct = nf_ct_get(skb, &ctinfo); 32 if (ct == NULL) 33 return invert; 34 35 labels = nf_ct_labels_find(ct); 36 if (!labels) 37 return invert; 38 39 if (test_bit(info->bit, labels->bits)) 40 return !invert; 41 42 if (info->options & XT_CONNLABEL_OP_SET) { 43 if (!test_and_set_bit(info->bit, labels->bits)) 44 nf_conntrack_event_cache(IPCT_LABEL, ct); 45 46 return !invert; 47 } 48 49 return invert; 50 } 51 52 static int connlabel_mt_check(const struct xt_mtchk_param *par) 53 { 54 const int options = XT_CONNLABEL_OP_INVERT | 55 XT_CONNLABEL_OP_SET; 56 struct xt_connlabel_mtinfo *info = par->matchinfo; 57 int ret; 58 59 if (info->options & ~options) { 60 pr_info_ratelimited("Unknown options in mask %x\n", 61 info->options); 62 return -EINVAL; 63 } 64 65 ret = nf_ct_netns_get(par->net, par->family); 66 if (ret < 0) { 67 pr_info_ratelimited("cannot load conntrack support for proto=%u\n", 68 par->family); 69 return ret; 70 } 71 72 ret = nf_connlabels_get(par->net, info->bit); 73 if (ret < 0) 74 nf_ct_netns_put(par->net, par->family); 75 return ret; 76 } 77 78 static void connlabel_mt_destroy(const struct xt_mtdtor_param *par) 79 { 80 nf_connlabels_put(par->net); 81 nf_ct_netns_put(par->net, par->family); 82 } 83 84 static struct xt_match connlabels_mt_reg __read_mostly = { 85 .name = "connlabel", 86 .family = NFPROTO_UNSPEC, 87 .checkentry = connlabel_mt_check, 88 .match = connlabel_mt, 89 .matchsize = sizeof(struct xt_connlabel_mtinfo), 90 .destroy = connlabel_mt_destroy, 91 .me = THIS_MODULE, 92 }; 93 94 static int __init connlabel_mt_init(void) 95 { 96 return xt_register_match(&connlabels_mt_reg); 97 } 98 99 static void __exit connlabel_mt_exit(void) 100 { 101 xt_unregister_match(&connlabels_mt_reg); 102 } 103 104 module_init(connlabel_mt_init); 105 module_exit(connlabel_mt_exit); 106