/* * 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/init.h>#include <linux/netdevice.h>#include <linux/netfilter.h>#include <linux/spinlock.h>#include <linux/netlink.h>#include <net/sock.h>#include <net/flow.h>#include <net/dn.h>#include <net/dn_route.h>#include <linux/netfilter_decnet.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;	unsigned char *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);	memcpy(ptr, rt_skb->data, rt_skb->len);	nlh->nlmsg_len = skb->tail - old_tail;	return skb;nlmsg_failure:	if (skb)		kfree_skb(skb);	*errp = -ENOMEM;	if (net_ratelimit())		printk(KERN_ERR "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 = DNRMG_L1_GROUP;			break;		case DN_RT_PKT_L2RT:			group = DNRMG_L2_GROUP;			break;		default:			return;	}	skb2 = dnrmg_build_message(skb, &status);	if (skb2 == NULL)		return;	NETLINK_CB(skb2).dst_groups = group;	netlink_broadcast(dnrmg, skb2, 0, group, GFP_ATOMIC);}static unsigned int dnrmg_hook(unsigned int hook,			struct sk_buff **pskb,			const struct net_device *in,			const struct net_device *out,			int (*okfn)(struct sk_buff *)){	dnrmg_send_peer(*pskb);	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 = (struct nlmsghdr *)skb->data;	if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len)		return;	if (!cap_raised(NETLINK_CB(skb).eff_cap, CAP_NET_ADMIN))		RCV_SKB_FAIL(-EPERM);	/* Eventually we might send routing messages too */	RCV_SKB_FAIL(-EINVAL);}static void dnrmg_receive_user_sk(struct sock *sk, int len){	struct sk_buff *skb;	while((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {		dnrmg_receive_user_skb(skb);		kfree_skb(skb);	}}static struct nf_hook_ops dnrmg_ops = {	.hook		= dnrmg_hook,	.pf		= PF_DECnet,	.hooknum	= NF_DN_ROUTE,	.priority	= NF_DN_PRI_DNRTMSG,};static int __init init(void){	int rv = 0;	dnrmg = netlink_kernel_create(NETLINK_DNRTMSG, dnrmg_receive_user_sk);	if (dnrmg == NULL) {		printk(KERN_ERR "dn_rtmsg: Cannot create netlink socket");		return -ENOMEM;	}	rv = nf_register_hook(&dnrmg_ops);	if (rv) {		sock_release(dnrmg->sk_socket);	}	return rv;}static void __exit fini(void){	nf_unregister_hook(&dnrmg_ops);	sock_release(dnrmg->sk_socket);}MODULE_DESCRIPTION("DECnet Routing Message Grabulator");MODULE_AUTHOR("Steven Whitehouse <steve@chygwyn.com>");MODULE_LICENSE("GPL");module_init(init);module_exit(fini);