[deliverable/linux.git] / net / decnet / netfilter / dn_rtmsg.c

/*
 * DECnet       An implementation of the DECnet protocol suite for the LINUX
 *              operating system.  DECnet is implemented using the  BSD Socket
 *              interface as the means of communication with the user level.
 *
 *              DECnet Routing Message Grabulator
 *
 *              (C) 2000 ChyGwyn Limited  -  http://www.chygwyn.com/
 *              This code may be copied under the GPL v.2 or at your option
 *              any later version.
 *
 * Author:      Steven Whitehouse <steve@chygwyn.com>
 *
 */
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/netfilter.h>
#include <linux/spinlock.h>
#include <linux/netlink.h>
#include <linux/netfilter_decnet.h>

#include <net/sock.h>
#include <net/flow.h>
#include <net/dn.h>
#include <net/dn_route.h>

static struct sock *dnrmg = NULL;


static struct sk_buff *dnrmg_build_message(struct sk_buff *rt_skb, int *errp)
{
	struct sk_buff *skb = NULL;
	size_t size;
	sk_buff_data_t old_tail;
	struct nlmsghdr *nlh;
	unsigned char *ptr;
	struct nf_dn_rtmsg *rtm;

	size = NLMSG_SPACE(rt_skb->len);
	size += NLMSG_ALIGN(sizeof(struct nf_dn_rtmsg));
	skb = alloc_skb(size, GFP_ATOMIC);
	if (!skb)
		goto nlmsg_failure;
	old_tail = skb->tail;
	nlh = NLMSG_PUT(skb, 0, 0, 0, size - sizeof(*nlh));
	rtm = (struct nf_dn_rtmsg *)NLMSG_DATA(nlh);
	rtm->nfdn_ifindex = rt_skb->dev->ifindex;
	ptr = NFDN_RTMSG(rtm);
	skb_copy_from_linear_data(rt_skb, ptr, rt_skb->len);
	nlh->nlmsg_len = skb->tail - old_tail;
	return skb;

nlmsg_failure:
	if (skb)
		kfree_skb(skb);
	*errp = -ENOMEM;
	net_err_ratelimited("dn_rtmsg: error creating netlink message\n");
	return NULL;
}

static void dnrmg_send_peer(struct sk_buff *skb)
{
	struct sk_buff *skb2;
	int status = 0;
	int group = 0;
	unsigned char flags = *skb->data;

	switch (flags & DN_RT_CNTL_MSK) {
	case DN_RT_PKT_L1RT:
		group = DNRNG_NLGRP_L1;
		break;
	case DN_RT_PKT_L2RT:
		group = DNRNG_NLGRP_L2;
		break;
	default:
		return;
	}

	skb2 = dnrmg_build_message(skb, &status);
	if (skb2 == NULL)
		return;
	NETLINK_CB(skb2).dst_group = group;
	netlink_broadcast(dnrmg, skb2, 0, group, GFP_ATOMIC);
}


static unsigned int dnrmg_hook(unsigned int hook,
			struct sk_buff *skb,
			const struct net_device *in,
			const struct net_device *out,
			int (*okfn)(struct sk_buff *))
{
	dnrmg_send_peer(skb);
	return NF_ACCEPT;
}


#define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)

static inline void dnrmg_receive_user_skb(struct sk_buff *skb)
{
	struct nlmsghdr *nlh = nlmsg_hdr(skb);

	if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len)
		return;

	if (!capable(CAP_NET_ADMIN))
		RCV_SKB_FAIL(-EPERM);

	/* Eventually we might send routing messages too */

	RCV_SKB_FAIL(-EINVAL);
}

static struct nf_hook_ops dnrmg_ops __read_mostly = {
	.hook		= dnrmg_hook,
	.pf		= PF_DECnet,
	.hooknum	= NF_DN_ROUTE,
	.priority	= NF_DN_PRI_DNRTMSG,
};

static int __init dn_rtmsg_init(void)
{
	int rv = 0;

	dnrmg = netlink_kernel_create(&init_net,
				      NETLINK_DNRTMSG, DNRNG_NLGRP_MAX,
				      dnrmg_receive_user_skb,
				      NULL, THIS_MODULE);
	if (dnrmg == NULL) {
		printk(KERN_ERR "dn_rtmsg: Cannot create netlink socket");
		return -ENOMEM;
	}

	rv = nf_register_hook(&dnrmg_ops);
	if (rv) {
		netlink_kernel_release(dnrmg);
	}

	return rv;
}

static void __exit dn_rtmsg_fini(void)
{
	nf_unregister_hook(&dnrmg_ops);
	netlink_kernel_release(dnrmg);
}


MODULE_DESCRIPTION("DECnet Routing Message Grabulator");
MODULE_AUTHOR("Steven Whitehouse <steve@chygwyn.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_DNRTMSG);

module_init(dn_rtmsg_init);
module_exit(dn_rtmsg_fini);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* DECnet An implementation of the DECnet protocol suite for the LINUX
	3	* operating system. DECnet is implemented using the BSD Socket
	4	* interface as the means of communication with the user level.
	5	*
	6	* DECnet Routing Message Grabulator
	7	*
	8	* (C) 2000 ChyGwyn Limited - http://www.chygwyn.com/
	9	* This code may be copied under the GPL v.2 or at your option
	10	* any later version.
	11	*
	12	* Author: Steven Whitehouse <steve@chygwyn.com>
	13	*
	14	*/
	15	#include <linux/module.h>
	16	#include <linux/skbuff.h>
5a0e3ad6	17	#include <linux/slab.h>
1da177e4 LT	18	#include <linux/init.h>
	19	#include <linux/netdevice.h>
	20	#include <linux/netfilter.h>
	21	#include <linux/spinlock.h>
	22	#include <linux/netlink.h>
63a1222b	23	#include <linux/netfilter_decnet.h>
1da177e4 LT	24
	25	#include <net/sock.h>
	26	#include <net/flow.h>
	27	#include <net/dn.h>
	28	#include <net/dn_route.h>
	29
1da177e4 LT	30	static struct sock *dnrmg = NULL;
	31
	32
	33	static struct sk_buff dnrmg_build_message(struct sk_buff rt_skb, int *errp)
	34	{
	35	struct sk_buff *skb = NULL;
	36	size_t size;
27a884dc	37	sk_buff_data_t old_tail;
1da177e4 LT	38	struct nlmsghdr *nlh;
	39	unsigned char *ptr;
	40	struct nf_dn_rtmsg *rtm;
	41
	42	size = NLMSG_SPACE(rt_skb->len);
	43	size += NLMSG_ALIGN(sizeof(struct nf_dn_rtmsg));
	44	skb = alloc_skb(size, GFP_ATOMIC);
	45	if (!skb)
	46	goto nlmsg_failure;
	47	old_tail = skb->tail;
	48	nlh = NLMSG_PUT(skb, 0, 0, 0, size - sizeof(*nlh));
	49	rtm = (struct nf_dn_rtmsg *)NLMSG_DATA(nlh);
	50	rtm->nfdn_ifindex = rt_skb->dev->ifindex;
	51	ptr = NFDN_RTMSG(rtm);
1a4e2d09	52	skb_copy_from_linear_data(rt_skb, ptr, rt_skb->len);
1da177e4 LT	53	nlh->nlmsg_len = skb->tail - old_tail;
	54	return skb;
	55
	56	nlmsg_failure:
	57	if (skb)
	58	kfree_skb(skb);
	59	*errp = -ENOMEM;
e87cc472	60	net_err_ratelimited("dn_rtmsg: error creating netlink message\n");
1da177e4 LT	61	return NULL;
	62	}
	63
	64	static void dnrmg_send_peer(struct sk_buff *skb)
	65	{
	66	struct sk_buff *skb2;
	67	int status = 0;
	68	int group = 0;
	69	unsigned char flags = *skb->data;
	70
06f8fe11 JP	71	switch (flags & DN_RT_CNTL_MSK) {
	72	case DN_RT_PKT_L1RT:
	73	group = DNRNG_NLGRP_L1;
	74	break;
	75	case DN_RT_PKT_L2RT:
	76	group = DNRNG_NLGRP_L2;
	77	break;
	78	default:
	79	return;
1da177e4 LT	80	}
	81
	82	skb2 = dnrmg_build_message(skb, &status);
	83	if (skb2 == NULL)
	84	return;
ac6d439d	85	NETLINK_CB(skb2).dst_group = group;
1da177e4 LT	86	netlink_broadcast(dnrmg, skb2, 0, group, GFP_ATOMIC);
	87	}
	88
	89
	90	static unsigned int dnrmg_hook(unsigned int hook,
3db05fea	91	struct sk_buff *skb,
1da177e4 LT	92	const struct net_device *in,
	93	const struct net_device *out,
	94	int (okfn)(struct sk_buff ))
	95	{
3db05fea	96	dnrmg_send_peer(skb);
1da177e4 LT	97	return NF_ACCEPT;
	98	}
	99
	100
	101	#define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
	102
	103	static inline void dnrmg_receive_user_skb(struct sk_buff *skb)
	104	{
b529ccf2	105	struct nlmsghdr *nlh = nlmsg_hdr(skb);
1da177e4 LT	106
	107	if (nlh->nlmsg_len < sizeof(*nlh) \|\| skb->len < nlh->nlmsg_len)
	108	return;
	109
fd778461	110	if (!capable(CAP_NET_ADMIN))
1da177e4 LT	111	RCV_SKB_FAIL(-EPERM);
	112
	113	/* Eventually we might send routing messages too */
	114
	115	RCV_SKB_FAIL(-EINVAL);
	116	}
	117
1999414a	118	static struct nf_hook_ops dnrmg_ops __read_mostly = {
1da177e4 LT	119	.hook = dnrmg_hook,
	120	.pf = PF_DECnet,
	121	.hooknum = NF_DN_ROUTE,
	122	.priority = NF_DN_PRI_DNRTMSG,
	123	};
	124
65b4b4e8	125	static int __init dn_rtmsg_init(void)
1da177e4 LT	126	{
	127	int rv = 0;
	128
b4b51029 EB	129	dnrmg = netlink_kernel_create(&init_net,
b4b51029 EB	130	NETLINK_DNRTMSG, DNRNG_NLGRP_MAX,
cd40b7d3 DL	131	dnrmg_receive_user_skb,
cd40b7d3 DL	132	NULL, THIS_MODULE);
1da177e4 LT	133	if (dnrmg == NULL) {
	134	printk(KERN_ERR "dn_rtmsg: Cannot create netlink socket");
	135	return -ENOMEM;
	136	}
	137
	138	rv = nf_register_hook(&dnrmg_ops);
	139	if (rv) {
b7c6ba6e	140	netlink_kernel_release(dnrmg);
1da177e4 LT	141	}
	142
	143	return rv;
	144	}
	145
65b4b4e8	146	static void __exit dn_rtmsg_fini(void)
1da177e4 LT	147	{
1da177e4 LT	148	nf_unregister_hook(&dnrmg_ops);
b7c6ba6e	149	netlink_kernel_release(dnrmg);
1da177e4 LT	150	}
	151
	152
	153	MODULE_DESCRIPTION("DECnet Routing Message Grabulator");
	154	MODULE_AUTHOR("Steven Whitehouse <steve@chygwyn.com>");
	155	MODULE_LICENSE("GPL");
4fdb3bb7	156	MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_DNRTMSG);
1da177e4	157
65b4b4e8 AM	158	module_init(dn_rtmsg_init);
65b4b4e8 AM	159	module_exit(dn_rtmsg_fini);
1da177e4	160