// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* xt_connmark - Netfilter module to operate on connection marks
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*
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* Copyright (C) 2002,2004 MARA Systems AB <https://www.marasystems.com>
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* by Henrik Nordstrom <hno@marasystems.com>
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* Copyright © CC Computer Consultants GmbH, 2007 - 2008
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* Jan Engelhardt <jengelh@medozas.de>
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*/
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <net/netfilter/nf_conntrack.h>
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#include <net/netfilter/nf_conntrack_ecache.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter/xt_connmark.h>
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MODULE_AUTHOR("Henrik Nordstrom <hno@marasystems.com>");
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MODULE_DESCRIPTION("Xtables: connection mark operations");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("ipt_CONNMARK");
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MODULE_ALIAS("ip6t_CONNMARK");
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MODULE_ALIAS("ipt_connmark");
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MODULE_ALIAS("ip6t_connmark");
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static unsigned int
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connmark_tg_shift(struct sk_buff *skb, const struct xt_connmark_tginfo2 *info)
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{
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enum ip_conntrack_info ctinfo;
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u_int32_t new_targetmark;
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struct nf_conn *ct;
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u_int32_t newmark;
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u_int32_t oldmark;
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ct = nf_ct_get(skb, &ctinfo);
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if (ct == NULL)
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return XT_CONTINUE;
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switch (info->mode) {
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case XT_CONNMARK_SET:
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oldmark = READ_ONCE(ct->mark);
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newmark = (oldmark & ~info->ctmask) ^ info->ctmark;
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if (info->shift_dir == D_SHIFT_RIGHT)
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newmark >>= info->shift_bits;
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else
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newmark <<= info->shift_bits;
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if (READ_ONCE(ct->mark) != newmark) {
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WRITE_ONCE(ct->mark, newmark);
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nf_conntrack_event_cache(IPCT_MARK, ct);
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}
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break;
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case XT_CONNMARK_SAVE:
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new_targetmark = (skb->mark & info->nfmask);
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if (info->shift_dir == D_SHIFT_RIGHT)
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new_targetmark >>= info->shift_bits;
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else
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new_targetmark <<= info->shift_bits;
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newmark = (READ_ONCE(ct->mark) & ~info->ctmask) ^
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new_targetmark;
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if (READ_ONCE(ct->mark) != newmark) {
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WRITE_ONCE(ct->mark, newmark);
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nf_conntrack_event_cache(IPCT_MARK, ct);
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}
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break;
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case XT_CONNMARK_RESTORE:
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new_targetmark = (READ_ONCE(ct->mark) & info->ctmask);
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if (info->shift_dir == D_SHIFT_RIGHT)
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new_targetmark >>= info->shift_bits;
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else
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new_targetmark <<= info->shift_bits;
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newmark = (skb->mark & ~info->nfmask) ^
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new_targetmark;
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skb->mark = newmark;
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break;
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}
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return XT_CONTINUE;
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}
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static unsigned int
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connmark_tg(struct sk_buff *skb, const struct xt_action_param *par)
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{
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const struct xt_connmark_tginfo1 *info = par->targinfo;
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const struct xt_connmark_tginfo2 info2 = {
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.ctmark = info->ctmark,
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.ctmask = info->ctmask,
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.nfmask = info->nfmask,
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.mode = info->mode,
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};
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return connmark_tg_shift(skb, &info2);
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}
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static unsigned int
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connmark_tg_v2(struct sk_buff *skb, const struct xt_action_param *par)
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{
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const struct xt_connmark_tginfo2 *info = par->targinfo;
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return connmark_tg_shift(skb, info);
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}
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static int connmark_tg_check(const struct xt_tgchk_param *par)
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{
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int ret;
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ret = nf_ct_netns_get(par->net, par->family);
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if (ret < 0)
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pr_info_ratelimited("cannot load conntrack support for proto=%u\n",
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par->family);
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return ret;
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}
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static void connmark_tg_destroy(const struct xt_tgdtor_param *par)
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{
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nf_ct_netns_put(par->net, par->family);
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}
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static bool
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connmark_mt(const struct sk_buff *skb, struct xt_action_param *par)
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{
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const struct xt_connmark_mtinfo1 *info = par->matchinfo;
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enum ip_conntrack_info ctinfo;
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const struct nf_conn *ct;
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ct = nf_ct_get(skb, &ctinfo);
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if (ct == NULL)
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return false;
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return ((READ_ONCE(ct->mark) & info->mask) == info->mark) ^ info->invert;
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}
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static int connmark_mt_check(const struct xt_mtchk_param *par)
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{
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int ret;
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ret = nf_ct_netns_get(par->net, par->family);
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if (ret < 0)
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pr_info_ratelimited("cannot load conntrack support for proto=%u\n",
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par->family);
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return ret;
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}
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static void connmark_mt_destroy(const struct xt_mtdtor_param *par)
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{
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nf_ct_netns_put(par->net, par->family);
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}
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static struct xt_target connmark_tg_reg[] __read_mostly = {
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{
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.name = "CONNMARK",
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.revision = 1,
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.family = NFPROTO_UNSPEC,
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.checkentry = connmark_tg_check,
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.target = connmark_tg,
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.targetsize = sizeof(struct xt_connmark_tginfo1),
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.destroy = connmark_tg_destroy,
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.me = THIS_MODULE,
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},
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{
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.name = "CONNMARK",
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.revision = 2,
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.family = NFPROTO_UNSPEC,
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.checkentry = connmark_tg_check,
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.target = connmark_tg_v2,
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.targetsize = sizeof(struct xt_connmark_tginfo2),
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.destroy = connmark_tg_destroy,
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.me = THIS_MODULE,
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}
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};
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static struct xt_match connmark_mt_reg __read_mostly = {
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.name = "connmark",
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.revision = 1,
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.family = NFPROTO_UNSPEC,
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.checkentry = connmark_mt_check,
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.match = connmark_mt,
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.matchsize = sizeof(struct xt_connmark_mtinfo1),
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.destroy = connmark_mt_destroy,
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.me = THIS_MODULE,
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};
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static int __init connmark_mt_init(void)
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{
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int ret;
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ret = xt_register_targets(connmark_tg_reg,
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ARRAY_SIZE(connmark_tg_reg));
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if (ret < 0)
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return ret;
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ret = xt_register_match(&connmark_mt_reg);
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if (ret < 0) {
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xt_unregister_targets(connmark_tg_reg,
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ARRAY_SIZE(connmark_tg_reg));
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return ret;
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}
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return 0;
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}
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static void __exit connmark_mt_exit(void)
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{
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xt_unregister_match(&connmark_mt_reg);
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xt_unregister_targets(connmark_tg_reg, ARRAY_SIZE(connmark_tg_reg));
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}
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module_init(connmark_mt_init);
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module_exit(connmark_mt_exit);
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