Florian Westphal | c539f01 | 2013-01-11 06:30:44 +0000 | [diff] [blame] | 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_labels.h> |
| 13 | #include <linux/netfilter/x_tables.h> |
| 14 | |
| 15 | MODULE_LICENSE("GPL"); |
| 16 | MODULE_AUTHOR("Florian Westphal <fw@strlen.de>"); |
| 17 | MODULE_DESCRIPTION("Xtables: add/match connection trackling labels"); |
| 18 | MODULE_ALIAS("ipt_connlabel"); |
| 19 | MODULE_ALIAS("ip6t_connlabel"); |
| 20 | |
| 21 | static bool |
| 22 | connlabel_mt(const struct sk_buff *skb, struct xt_action_param *par) |
| 23 | { |
| 24 | const struct xt_connlabel_mtinfo *info = par->matchinfo; |
| 25 | enum ip_conntrack_info ctinfo; |
| 26 | struct nf_conn *ct; |
| 27 | bool invert = info->options & XT_CONNLABEL_OP_INVERT; |
| 28 | |
| 29 | ct = nf_ct_get(skb, &ctinfo); |
| 30 | if (ct == NULL || nf_ct_is_untracked(ct)) |
| 31 | return invert; |
| 32 | |
| 33 | if (info->options & XT_CONNLABEL_OP_SET) |
| 34 | return (nf_connlabel_set(ct, info->bit) == 0) ^ invert; |
| 35 | |
| 36 | return nf_connlabel_match(ct, info->bit) ^ invert; |
| 37 | } |
| 38 | |
| 39 | static int connlabel_mt_check(const struct xt_mtchk_param *par) |
| 40 | { |
| 41 | const int options = XT_CONNLABEL_OP_INVERT | |
| 42 | XT_CONNLABEL_OP_SET; |
| 43 | struct xt_connlabel_mtinfo *info = par->matchinfo; |
| 44 | int ret; |
| 45 | size_t words; |
| 46 | |
| 47 | if (info->bit > XT_CONNLABEL_MAXBIT) |
| 48 | return -ERANGE; |
| 49 | |
| 50 | if (info->options & ~options) { |
| 51 | pr_err("Unknown options in mask %x\n", info->options); |
| 52 | return -EINVAL; |
| 53 | } |
| 54 | |
| 55 | ret = nf_ct_l3proto_try_module_get(par->family); |
| 56 | if (ret < 0) { |
| 57 | pr_info("cannot load conntrack support for proto=%u\n", |
| 58 | par->family); |
| 59 | return ret; |
| 60 | } |
| 61 | |
| 62 | par->net->ct.labels_used++; |
| 63 | words = BITS_TO_LONGS(info->bit+1); |
| 64 | if (words > par->net->ct.label_words) |
| 65 | par->net->ct.label_words = words; |
| 66 | |
| 67 | return ret; |
| 68 | } |
| 69 | |
| 70 | static void connlabel_mt_destroy(const struct xt_mtdtor_param *par) |
| 71 | { |
| 72 | par->net->ct.labels_used--; |
| 73 | if (par->net->ct.labels_used == 0) |
| 74 | par->net->ct.label_words = 0; |
| 75 | nf_ct_l3proto_module_put(par->family); |
| 76 | } |
| 77 | |
| 78 | static struct xt_match connlabels_mt_reg __read_mostly = { |
| 79 | .name = "connlabel", |
| 80 | .family = NFPROTO_UNSPEC, |
| 81 | .checkentry = connlabel_mt_check, |
| 82 | .match = connlabel_mt, |
| 83 | .matchsize = sizeof(struct xt_connlabel_mtinfo), |
| 84 | .destroy = connlabel_mt_destroy, |
| 85 | .me = THIS_MODULE, |
| 86 | }; |
| 87 | |
| 88 | static int __init connlabel_mt_init(void) |
| 89 | { |
| 90 | return xt_register_match(&connlabels_mt_reg); |
| 91 | } |
| 92 | |
| 93 | static void __exit connlabel_mt_exit(void) |
| 94 | { |
| 95 | xt_unregister_match(&connlabels_mt_reg); |
| 96 | } |
| 97 | |
| 98 | module_init(connlabel_mt_init); |
| 99 | module_exit(connlabel_mt_exit); |