patch-1.3.31 linux/net/netlink.c

• Lines: 251
• Date: Mon Oct 2 14:25:13 1995
• Orig file: v1.3.30/linux/net/netlink.c
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.30/linux/net/netlink.c linux/net/netlink.c
@@ -0,0 +1,250 @@
+/*
+ * SKIPLINK	An implementation of a loadable kernel mode driver providing
+ *		multiple kernel/user space bidirectional communications links.
+ *
+ * 		Author: 	Alan Cox <alan@cymru.net>
+ *
+ *		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.
+ * 
+ */
+
+#include <linux/config.h>
+
+#if defined(CONFIG_NETLINK) || defined(MODULE)
+#ifdef MODULE
+#include <linux/module.h>
+#include <linux/version.h>
+#else
+#define MOD_INC_USE_COUNT
+#define MOD_DEC_USE_COUNT
+#endif
+
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/major.h>
+#include <linux/sched.h>
+#include <linux/lp.h>
+#include <linux/malloc.h>
+#include <linux/ioport.h>
+#include <linux/fcntl.h>
+#include <linux/delay.h>
+#include <linux/skbuff.h>
+
+#include <net/netlink.h>
+
+#include <asm/io.h>
+#include <asm/segment.h>
+#include <asm/system.h>
+
+static int (*netlink_handler[MAX_LINKS])(struct sk_buff *skb);
+static struct sk_buff_head skb_queue_rd[MAX_LINKS]; 
+static int rdq_size[MAX_LINKS];
+static struct wait_queue *read_space_wait[MAX_LINKS];
+
+static int active_map = 0;
+static int open_map = 0;
+
+/*
+ *	Device operations
+ */
+ 
+/*
+ *	Default write handler.
+ */
+ 
+static int netlink_err(struct sk_buff *skb)
+{
+	kfree_skb(skb, FREE_READ);
+	return -EUNATCH;
+}
+ 
+/*
+ *	Write a message to the kernel side of a communication link
+ */
+ 
+static int netlink_write(struct inode * inode, struct file * file, const char * buf, int count)
+{
+	unsigned int minor = MINOR(inode->i_rdev);
+	struct sk_buff *skb;
+	skb=alloc_skb(count, GFP_KERNEL);
+	memcpy_fromfs(skb_put(skb,count),buf, count);
+	return (netlink_handler[minor])(skb);
+}
+
+/*
+ *	Read a message from the kernel side of the communication link
+ */
+
+static int netlink_read(struct inode * inode, struct file * file, char * buf, int count)
+{
+	unsigned int minor = MINOR(inode->i_rdev);
+	struct sk_buff *skb;
+	cli();
+	while((skb=skb_dequeue(&skb_queue_rd[minor]))==NULL)
+	{
+		if(file->f_flags&O_NONBLOCK)
+		{
+			sti();
+			return -EWOULDBLOCK;
+		}
+		interruptible_sleep_on(&read_space_wait[minor]);
+		if(current->signal & ~current->blocked)
+		{
+			sti();
+			return -ERESTARTSYS;
+		}
+	}
+	rdq_size[minor]-=skb->len;
+	sti();
+	if(skb->len<count)
+		count=skb->len;
+	memcpy_tofs(buf,skb->data,count);
+	kfree_skb(skb, FREE_READ);
+	return count;
+}
+
+static int netlink_lseek(struct inode * inode, struct file * file,
+		    off_t offset, int origin)
+{
+	return -ESPIPE;
+}
+
+static int netlink_open(struct inode * inode, struct file * file)
+{
+	unsigned int minor = MINOR(inode->i_rdev);
+	
+	if(minor>=MAX_LINKS)
+		return -ENODEV;
+	if(open_map&(1<<minor))
+		return -EBUSY;
+	if(active_map&(1<<minor))
+	{
+		open_map|=(1<<minor);
+		return 0;
+	}
+	return -EUNATCH;
+}
+
+static void netlink_release(struct inode * inode, struct file * file)
+{
+	unsigned int minor = MINOR(inode->i_rdev);
+	open_map&=~(1<<minor);	
+	MOD_DEC_USE_COUNT;
+}
+
+
+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 = {
+	netlink_lseek,
+	netlink_read,
+	netlink_write,
+	NULL,		/* netlink_readdir */
+	NULL,		/* netlink_select */
+	netlink_ioctl,
+	NULL,		/* netlink_mmap */
+	netlink_open,
+	netlink_release
+};
+
+/*
+ *	We export these functions to other modules. They provide a 
+ *	complete set of kernel non-blocking support for message
+ *	queueing.
+ */
+ 
+int netlink_attach(int unit, int (*function)(struct sk_buff *skb))
+{
+	if(unit>=MAX_LINKS)
+		return -ENODEV;
+	if(active_map&(1<<unit))
+		return -EBUSY;
+	active_map|=(1<<unit);
+	netlink_handler[unit]=function;
+	return 0;
+}
+
+void netlink_detach(int unit)
+{
+	active_map&=~(1<<unit);
+	netlink_handler[unit]=netlink_err;
+}
+
+int netlink_post(int unit, struct sk_buff *skb)
+{
+	unsigned long flags;
+	int ret;
+	save_flags(flags);
+	cli();
+	if(rdq_size[unit]+skb->len>MAX_QBYTES)
+		ret=-EWOULDBLOCK;
+	else
+	{
+		skb_queue_tail(&skb_queue_rd[unit], skb);
+		rdq_size[unit]+=skb->len;
+		ret=0;
+		wake_up_interruptible(&read_space_wait[MAX_LINKS]);
+	}
+	restore_flags(flags);
+	return ret;
+}
+
+
+#ifdef MODULE
+char kernel_version[]=UTS_RELEASE;
+
+int init_module(void)
+{
+	int ct;
+	printk("Network Kernel/User communications module 0.01 ALPHA\n");
+	if (register_chrdev(NET_MAJOR,"netlink",&netlink_fops)) {
+		printk("netlink: unable to get major %d\n", NET_MAJOR);
+		return -EIO;
+	}
+	for(ct=0;ct<MAX_LINKS;ct++)
+	{
+		skb_queue_head_init(&skb_queue_rd[ct]);
+		netlink_handler[ct]=netlink_err;
+	}
+	return 0;
+}
+
+void cleanup_module(void)
+{
+	unregister_chrdev(NET_MAJOR,"netlink");
+}
+
+#else
+
+void init_netlink(void)
+{
+	int ct;
+	/* Keep quiet on booting, we don't want too many messages */
+	if(register_chrdev(NET_MAJOR,"netlink", &netlink_fops))
+		printk("netlink: unable to get major %d\n", NET_MAJOR);
+	for(ct=0;ct<MAX_LINKS;ct++)
+	{
+		skb_queue_head_init(&skb_queue_rd[ct]);
+		netlink_handler[ct]=netlink_err;
+	}
+}
+
+#endif
+#endif