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/*
* NETLINK An implementation of a loadable kernel mode driver providing
* multiple kernel/user space bidirectional communications links.
*
* Author: Alan Cox <alan@redhat.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Now netlink devices are emulated on the top of netlink sockets
* by compatibility reasons. Remove this file after a period. --ANK
*
*/
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/devfs_fs_kernel.h>
#include <linux/smp_lock.h>
#include <asm/bitops.h>
#include <asm/system.h>
#include <asm/uaccess.h>
static long open_map;
static struct socket *netlink_user[MAX_LINKS];
/*
* Device operations
*/
static unsigned int netlink_poll(struct file *file, poll_table * wait)
{
struct socket *sock = netlink_user[MINOR(file->f_dentry->d_inode->i_rdev)];
if (sock->ops->poll==NULL)
return 0;
return sock->ops->poll(file, sock, wait);
}
/*
* Write a message to the kernel side of a communication link
*/
static ssize_t netlink_write(struct file * file, const char * buf,
size_t count, loff_t *pos)
{
struct inode *inode = file->f_dentry->d_inode;
struct socket *sock = netlink_user[MINOR(inode->i_rdev)];
struct msghdr msg;
struct iovec iov;
iov.iov_base = (void*)buf;
iov.iov_len = count;
msg.msg_name=NULL;
msg.msg_namelen=0;
msg.msg_controllen=0;
msg.msg_flags=0;
msg.msg_iov=&iov;
msg.msg_iovlen=1;
return sock_sendmsg(sock, &msg, count);
}
/*
* Read a message from the kernel side of the communication link
*/
static ssize_t netlink_read(struct file * file, char * buf,
size_t count, loff_t *pos)
{
struct inode *inode = file->f_dentry->d_inode;
struct socket *sock = netlink_user[MINOR(inode->i_rdev)];
struct msghdr msg;
struct iovec iov;
iov.iov_base = buf;
iov.iov_len = count;
msg.msg_name=NULL;
msg.msg_namelen=0;
msg.msg_controllen=0;
msg.msg_flags=0;
msg.msg_iov=&iov;
msg.msg_iovlen=1;
if (file->f_flags&O_NONBLOCK)
msg.msg_flags=MSG_DONTWAIT;
return sock_recvmsg(sock, &msg, count, msg.msg_flags);
}
static int netlink_open(struct inode * inode, struct file * file)
{
unsigned int minor = MINOR(inode->i_rdev);
struct socket *sock;
struct sockaddr_nl nladdr;
int err;
if (minor>=MAX_LINKS)
return -ENODEV;
if (test_and_set_bit(minor, &open_map))
return -EBUSY;
err = sock_create(PF_NETLINK, SOCK_RAW, minor, &sock);
if (err < 0)
goto out;
memset(&nladdr, 0, sizeof(nladdr));
nladdr.nl_family = AF_NETLINK;
nladdr.nl_groups = ~0;
if ((err = sock->ops->bind(sock, (struct sockaddr*)&nladdr, sizeof(nladdr))) < 0) {
sock_release(sock);
goto out;
}
netlink_user[minor] = sock;
return 0;
out:
clear_bit(minor, &open_map);
return err;
}
static int netlink_release(struct inode * inode, struct file * file)
{
unsigned int minor = MINOR(inode->i_rdev);
struct socket *sock;
sock = netlink_user[minor];
netlink_user[minor] = NULL;
clear_bit(minor, &open_map);
sock_release(sock);
return 0;
}
static int netlink_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
unsigned int minor = MINOR(inode->i_rdev);
int retval = 0;
if (minor >= MAX_LINKS)
return -ENODEV;
switch ( cmd ) {
default:
retval = -EINVAL;
}
return retval;
}
static struct file_operations netlink_fops = {
owner: THIS_MODULE,
llseek: no_llseek,
read: netlink_read,
write: netlink_write,
poll: netlink_poll,
ioctl: netlink_ioctl,
open: netlink_open,
release: netlink_release,
};
static devfs_handle_t devfs_handle;
static void __init make_devfs_entries (const char *name, int minor)
{
devfs_register (devfs_handle, name, DEVFS_FL_DEFAULT,
NETLINK_MAJOR, minor,
S_IFCHR | S_IRUSR | S_IWUSR,
&netlink_fops, NULL);
}
int __init init_netlink(void)
{
if (devfs_register_chrdev(NETLINK_MAJOR,"netlink", &netlink_fops)) {
printk(KERN_ERR "netlink: unable to get major %d\n", NETLINK_MAJOR);
return -EIO;
}
devfs_handle = devfs_mk_dir (NULL, "netlink", NULL);
/* Someone tell me the official names for the uppercase ones */
make_devfs_entries ("route", 0);
make_devfs_entries ("skip", 1);
make_devfs_entries ("usersock", 2);
make_devfs_entries ("fwmonitor", 3);
make_devfs_entries ("tcpdiag", 4);
make_devfs_entries ("arpd", 8);
make_devfs_entries ("route6", 11);
make_devfs_entries ("ip6_fw", 13);
make_devfs_entries ("dnrtmsg", 13);
devfs_register_series (devfs_handle, "tap%u", 16, DEVFS_FL_DEFAULT,
NETLINK_MAJOR, 16,
S_IFCHR | S_IRUSR | S_IWUSR,
&netlink_fops, NULL);
return 0;
}
#ifdef MODULE
MODULE_LICENSE("GPL");
int init_module(void)
{
printk(KERN_INFO "Network Kernel/User communications module 0.04\n");
return init_netlink();
}
void cleanup_module(void)
{
devfs_unregister (devfs_handle);
devfs_unregister_chrdev(NETLINK_MAJOR, "netlink");
}
#endif
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