diff options
Diffstat (limited to 'net/netfilter/xt_state.c')
-rw-r--r-- | net/netfilter/xt_state.c | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/net/netfilter/xt_state.c b/net/netfilter/xt_state.c new file mode 100644 index 0000000000..bbe07b1be9 --- /dev/null +++ b/net/netfilter/xt_state.c @@ -0,0 +1,75 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Kernel module to match connection tracking information. */ + +/* (C) 1999-2001 Paul `Rusty' Russell + * (C) 2002-2005 Netfilter Core Team <coreteam@netfilter.org> + */ + +#include <linux/module.h> +#include <linux/skbuff.h> +#include <net/netfilter/nf_conntrack.h> +#include <linux/netfilter/x_tables.h> +#include <linux/netfilter/xt_state.h> + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>"); +MODULE_DESCRIPTION("ip[6]_tables connection tracking state match module"); +MODULE_ALIAS("ipt_state"); +MODULE_ALIAS("ip6t_state"); + +static bool +state_mt(const struct sk_buff *skb, struct xt_action_param *par) +{ + const struct xt_state_info *sinfo = par->matchinfo; + enum ip_conntrack_info ctinfo; + unsigned int statebit; + struct nf_conn *ct = nf_ct_get(skb, &ctinfo); + + if (ct) + statebit = XT_STATE_BIT(ctinfo); + else if (ctinfo == IP_CT_UNTRACKED) + statebit = XT_STATE_UNTRACKED; + else + statebit = XT_STATE_INVALID; + + return (sinfo->statemask & statebit); +} + +static int state_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 state_mt_destroy(const struct xt_mtdtor_param *par) +{ + nf_ct_netns_put(par->net, par->family); +} + +static struct xt_match state_mt_reg __read_mostly = { + .name = "state", + .family = NFPROTO_UNSPEC, + .checkentry = state_mt_check, + .match = state_mt, + .destroy = state_mt_destroy, + .matchsize = sizeof(struct xt_state_info), + .me = THIS_MODULE, +}; + +static int __init state_mt_init(void) +{ + return xt_register_match(&state_mt_reg); +} + +static void __exit state_mt_exit(void) +{ + xt_unregister_match(&state_mt_reg); +} + +module_init(state_mt_init); +module_exit(state_mt_exit); |