/*
 *  Simplified MAC Kernel (smack) security module
 *
 *  This file contains the Smack netfilter implementation
 *
 *  Author:
 *	Casey Schaufler <casey@schaufler-ca.com>
 *
 *  Copyright (C) 2014 Casey Schaufler <casey@schaufler-ca.com>
 *  Copyright (C) 2014 Intel Corporation.
 *
 *	This program is free software; you can redistribute it and/or modify
 *	it under the terms of the GNU General Public License version 2,
 *	as published by the Free Software Foundation.
 */

#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_ipv6.h>
#include <linux/netdevice.h>
#include "smack.h"

#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)

static unsigned int smack_ipv6_output(const struct nf_hook_ops *ops,
					struct sk_buff *skb,
					const struct net_device *in,
					const struct net_device *out,
					int (*okfn)(struct sk_buff *))
{
	struct socket_smack *ssp;
	struct smack_known *skp;

	if (skb && skb->sk && skb->sk->sk_security) {
		ssp = skb->sk->sk_security;
		skp = ssp->smk_out;
		skb->secmark = skp->smk_secid;
	}

	return NF_ACCEPT;
}
#endif	/* IPV6 */

static unsigned int smack_ipv4_output(const struct nf_hook_ops *ops,
					struct sk_buff *skb,
					const struct net_device *in,
					const struct net_device *out,
					int (*okfn)(struct sk_buff *))
{
	struct socket_smack *ssp;
	struct smack_known *skp;

	if (skb && skb->sk && skb->sk->sk_security) {
		ssp = skb->sk->sk_security;
		skp = ssp->smk_out;
		skb->secmark = skp->smk_secid;
	}

	return NF_ACCEPT;
}

static struct nf_hook_ops smack_nf_ops[] = {
	{
		.hook =		smack_ipv4_output,
		.owner =	THIS_MODULE,
		.pf =		NFPROTO_IPV4,
		.hooknum =	NF_INET_LOCAL_OUT,
		.priority =	NF_IP_PRI_SELINUX_FIRST,
	},
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
	{
		.hook =		smack_ipv6_output,
		.owner =	THIS_MODULE,
		.pf =		NFPROTO_IPV6,
		.hooknum =	NF_INET_LOCAL_OUT,
		.priority =	NF_IP6_PRI_SELINUX_FIRST,
	},
#endif	/* IPV6 */
};

static int __init smack_nf_ip_init(void)
{
	int err;

	if (smack_enabled == 0)
		return 0;

	printk(KERN_DEBUG "Smack: Registering netfilter hooks\n");

	err = nf_register_hooks(smack_nf_ops, ARRAY_SIZE(smack_nf_ops));
	if (err)
		pr_info("Smack: nf_register_hooks: error %d\n", err);

	return 0;
}

__initcall(smack_nf_ip_init);