1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4  */
5 
6 #include <linux/netdevice.h>
7 #include <linux/init.h>
8 #include <linux/skbuff.h>
9 #include <asm/errno.h>
10 #include <net_kern.h>
11 #include "tuntap.h"
12 
13 struct tuntap_init {
14 	char *dev_name;
15 	char *gate_addr;
16 };
17 
18 static void tuntap_init(struct net_device *dev, void *data)
19 {
20 	struct uml_net_private *pri;
21 	struct tuntap_data *tpri;
22 	struct tuntap_init *init = data;
23 
24 	pri = netdev_priv(dev);
25 	tpri = (struct tuntap_data *) pri->user;
26 	tpri->dev_name = init->dev_name;
27 	tpri->fixed_config = (init->dev_name != NULL);
28 	tpri->gate_addr = init->gate_addr;
29 	tpri->fd = -1;
30 	tpri->dev = dev;
31 
32 	printk(KERN_INFO "TUN/TAP backend - ");
33 	if (tpri->gate_addr != NULL)
34 		printk(KERN_CONT "IP = %s", tpri->gate_addr);
35 	printk(KERN_CONT "\n");
36 }
37 
38 static int tuntap_read(int fd, struct sk_buff *skb, struct uml_net_private *lp)
39 {
40 	return net_read(fd, skb_mac_header(skb),
41 			skb->dev->mtu + ETH_HEADER_OTHER);
42 }
43 
44 static int tuntap_write(int fd, struct sk_buff *skb, struct uml_net_private *lp)
45 {
46 	return net_write(fd, skb->data, skb->len);
47 }
48 
49 const struct net_kern_info tuntap_kern_info = {
50 	.init			= tuntap_init,
51 	.protocol		= eth_protocol,
52 	.read			= tuntap_read,
53 	.write 			= tuntap_write,
54 };
55 
56 int tuntap_setup(char *str, char **mac_out, void *data)
57 {
58 	struct tuntap_init *init = data;
59 
60 	*init = ((struct tuntap_init)
61 		{ .dev_name 	= NULL,
62 		  .gate_addr 	= NULL });
63 	if (tap_setup_common(str, "tuntap", &init->dev_name, mac_out,
64 			    &init->gate_addr))
65 		return 0;
66 
67 	return 1;
68 }
69 
70 static struct transport tuntap_transport = {
71 	.list 		= LIST_HEAD_INIT(tuntap_transport.list),
72 	.name 		= "tuntap",
73 	.setup  	= tuntap_setup,
74 	.user 		= &tuntap_user_info,
75 	.kern 		= &tuntap_kern_info,
76 	.private_size 	= sizeof(struct tuntap_data),
77 	.setup_size 	= sizeof(struct tuntap_init),
78 };
79 
80 static int register_tuntap(void)
81 {
82 	register_transport(&tuntap_transport);
83 	return 0;
84 }
85 
86 late_initcall(register_tuntap);
87