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* 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 <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;
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 = 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 **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;
unsigned int qlen = skb_queue_len(&sk->sk_receive_queue);
for (; qlen && (skb = skb_dequeue(&sk->sk_receive_queue)); qlen--) {
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, DNRNG_NLGRP_MAX,
dnrmg_receive_user_sk, THIS_MODULE);
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_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_DNRTMSG);
module_init(init);
module_exit(fini);
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