diff options
Diffstat (limited to 'net/netfilter/xt_connmark.c')
| -rw-r--r-- | net/netfilter/xt_connmark.c | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/net/netfilter/xt_connmark.c b/net/netfilter/xt_connmark.c new file mode 100644 index 000000000..ad3c033db --- /dev/null +++ b/net/netfilter/xt_connmark.c @@ -0,0 +1,208 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * xt_connmark - Netfilter module to operate on connection marks + * + * Copyright (C) 2002,2004 MARA Systems AB <https://www.marasystems.com> + * by Henrik Nordstrom <hno@marasystems.com> + * Copyright © CC Computer Consultants GmbH, 2007 - 2008 + * Jan Engelhardt <jengelh@medozas.de> + */ + +#include <linux/module.h> +#include <linux/skbuff.h> +#include <net/netfilter/nf_conntrack.h> +#include <net/netfilter/nf_conntrack_ecache.h> +#include <linux/netfilter/x_tables.h> +#include <linux/netfilter/xt_connmark.h> + +MODULE_AUTHOR("Henrik Nordstrom <hno@marasystems.com>"); +MODULE_DESCRIPTION("Xtables: connection mark operations"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("ipt_CONNMARK"); +MODULE_ALIAS("ip6t_CONNMARK"); +MODULE_ALIAS("ipt_connmark"); +MODULE_ALIAS("ip6t_connmark"); + +static unsigned int +connmark_tg_shift(struct sk_buff *skb, const struct xt_connmark_tginfo2 *info) +{ + enum ip_conntrack_info ctinfo; + u_int32_t new_targetmark; + struct nf_conn *ct; + u_int32_t newmark; + u_int32_t oldmark; + + ct = nf_ct_get(skb, &ctinfo); + if (ct == NULL) + return XT_CONTINUE; + + switch (info->mode) { + case XT_CONNMARK_SET: + oldmark = READ_ONCE(ct->mark); + newmark = (oldmark & ~info->ctmask) ^ info->ctmark; + if (info->shift_dir == D_SHIFT_RIGHT) + newmark >>= info->shift_bits; + else + newmark <<= info->shift_bits; + + if (READ_ONCE(ct->mark) != newmark) { + WRITE_ONCE(ct->mark, newmark); + nf_conntrack_event_cache(IPCT_MARK, ct); + } + break; + case XT_CONNMARK_SAVE: + new_targetmark = (skb->mark & info->nfmask); + if (info->shift_dir == D_SHIFT_RIGHT) + new_targetmark >>= info->shift_bits; + else + new_targetmark <<= info->shift_bits; + + newmark = (READ_ONCE(ct->mark) & ~info->ctmask) ^ + new_targetmark; + if (READ_ONCE(ct->mark) != newmark) { + WRITE_ONCE(ct->mark, newmark); + nf_conntrack_event_cache(IPCT_MARK, ct); + } + break; + case XT_CONNMARK_RESTORE: + new_targetmark = (READ_ONCE(ct->mark) & info->ctmask); + if (info->shift_dir == D_SHIFT_RIGHT) + new_targetmark >>= info->shift_bits; + else + new_targetmark <<= info->shift_bits; + + newmark = (skb->mark & ~info->nfmask) ^ + new_targetmark; + skb->mark = newmark; + break; + } + return XT_CONTINUE; +} + +static unsigned int +connmark_tg(struct sk_buff *skb, const struct xt_action_param *par) +{ + const struct xt_connmark_tginfo1 *info = par->targinfo; + const struct xt_connmark_tginfo2 info2 = { + .ctmark = info->ctmark, + .ctmask = info->ctmask, + .nfmask = info->nfmask, + .mode = info->mode, + }; + + return connmark_tg_shift(skb, &info2); +} + +static unsigned int +connmark_tg_v2(struct sk_buff *skb, const struct xt_action_param *par) +{ + const struct xt_connmark_tginfo2 *info = par->targinfo; + + return connmark_tg_shift(skb, info); +} + +static int connmark_tg_check(const struct xt_tgchk_param *par) +{ + int ret; + + ret = nf_ct_netns_get(par->net, par->family); + if (ret < 0) + pr_info_ratelimited("cannot load conntrack support for proto=%u\n", + par->family); + return ret; +} + +static void connmark_tg_destroy(const struct xt_tgdtor_param *par) +{ + nf_ct_netns_put(par->net, par->family); +} + +static bool +connmark_mt(const struct sk_buff *skb, struct xt_action_param *par) +{ + const struct xt_connmark_mtinfo1 *info = par->matchinfo; + enum ip_conntrack_info ctinfo; + const struct nf_conn *ct; + + ct = nf_ct_get(skb, &ctinfo); + if (ct == NULL) + return false; + + return ((READ_ONCE(ct->mark) & info->mask) == info->mark) ^ info->invert; +} + +static int connmark_mt_check(const struct xt_mtchk_param *par) +{ + int ret; + + ret = nf_ct_netns_get(par->net, par->family); + if (ret < 0) + pr_info_ratelimited("cannot load conntrack support for proto=%u\n", + par->family); + return ret; +} + +static void connmark_mt_destroy(const struct xt_mtdtor_param *par) +{ + nf_ct_netns_put(par->net, par->family); +} + +static struct xt_target connmark_tg_reg[] __read_mostly = { + { + .name = "CONNMARK", + .revision = 1, + .family = NFPROTO_UNSPEC, + .checkentry = connmark_tg_check, + .target = connmark_tg, + .targetsize = sizeof(struct xt_connmark_tginfo1), + .destroy = connmark_tg_destroy, + .me = THIS_MODULE, + }, + { + .name = "CONNMARK", + .revision = 2, + .family = NFPROTO_UNSPEC, + .checkentry = connmark_tg_check, + .target = connmark_tg_v2, + .targetsize = sizeof(struct xt_connmark_tginfo2), + .destroy = connmark_tg_destroy, + .me = THIS_MODULE, + } +}; + +static struct xt_match connmark_mt_reg __read_mostly = { + .name = "connmark", + .revision = 1, + .family = NFPROTO_UNSPEC, + .checkentry = connmark_mt_check, + .match = connmark_mt, + .matchsize = sizeof(struct xt_connmark_mtinfo1), + .destroy = connmark_mt_destroy, + .me = THIS_MODULE, +}; + +static int __init connmark_mt_init(void) +{ + int ret; + + ret = xt_register_targets(connmark_tg_reg, + ARRAY_SIZE(connmark_tg_reg)); + if (ret < 0) + return ret; + ret = xt_register_match(&connmark_mt_reg); + if (ret < 0) { + xt_unregister_targets(connmark_tg_reg, + ARRAY_SIZE(connmark_tg_reg)); + return ret; + } + return 0; +} + +static void __exit connmark_mt_exit(void) +{ + xt_unregister_match(&connmark_mt_reg); + xt_unregister_targets(connmark_tg_reg, ARRAY_SIZE(connmark_tg_reg)); +} + +module_init(connmark_mt_init); +module_exit(connmark_mt_exit); |