1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org) and
4 * James Leu (jleu@mindspring.net).
5 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
6 * Copyright (C) 2001 by various other people who didn't put their name here.
7 */
8
9#include <linux/init.h>
10#include <linux/netdevice.h>
11#include "etap.h"
12#include <net_kern.h>
13
14struct ethertap_init {
15	char *dev_name;
16	char *gate_addr;
17};
18
19static void etap_init(struct net_device *dev, void *data)
20{
21	struct uml_net_private *pri;
22	struct ethertap_data *epri;
23	struct ethertap_init *init = data;
24
25	pri = netdev_priv(dev);
26	epri = (struct ethertap_data *) pri->user;
27	epri->dev_name = init->dev_name;
28	epri->gate_addr = init->gate_addr;
29	epri->data_fd = -1;
30	epri->control_fd = -1;
31	epri->dev = dev;
32
33	printk(KERN_INFO "ethertap backend - %s", epri->dev_name);
34	if (epri->gate_addr != NULL)
35		printk(KERN_CONT ", IP = %s", epri->gate_addr);
36	printk(KERN_CONT "\n");
37}
38
39static int etap_read(int fd, struct sk_buff *skb, struct uml_net_private *lp)
40{
41	int len;
42
43	len = net_recvfrom(fd, skb_mac_header(skb),
44			   skb->dev->mtu + 2 + ETH_HEADER_ETHERTAP);
45	if (len <= 0)
46		return(len);
47
48	skb_pull(skb, 2);
49	len -= 2;
50	return len;
51}
52
53static int etap_write(int fd, struct sk_buff *skb, struct uml_net_private *lp)
54{
55	skb_push(skb, 2);
56	return net_send(fd, skb->data, skb->len);
57}
58
59const struct net_kern_info ethertap_kern_info = {
60	.init			= etap_init,
61	.protocol		= eth_protocol,
62	.read			= etap_read,
63	.write 			= etap_write,
64};
65
66int ethertap_setup(char *str, char **mac_out, void *data)
67{
68	struct ethertap_init *init = data;
69
70	*init = ((struct ethertap_init)
71		{ .dev_name 	= NULL,
72		  .gate_addr 	= NULL });
73	if (tap_setup_common(str, "ethertap", &init->dev_name, mac_out,
74			    &init->gate_addr))
75		return 0;
76	if (init->dev_name == NULL) {
77		printk(KERN_ERR "ethertap_setup : Missing tap device name\n");
78		return 0;
79	}
80
81	return 1;
82}
83
84static struct transport ethertap_transport = {
85	.list 		= LIST_HEAD_INIT(ethertap_transport.list),
86	.name 		= "ethertap",
87	.setup  	= ethertap_setup,
88	.user 		= &ethertap_user_info,
89	.kern 		= &ethertap_kern_info,
90	.private_size 	= sizeof(struct ethertap_data),
91	.setup_size 	= sizeof(struct ethertap_init),
92};
93
94static int register_ethertap(void)
95{
96	register_transport(&ethertap_transport);
97	return 0;
98}
99
100late_initcall(register_ethertap);
101