1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 */
5
6#include <linux/if_arp.h>
7#include <linux/init.h>
8#include <linux/netdevice.h>
9#include <net_kern.h>
10#include "slip.h"
11
12struct slip_init {
13 char *gate_addr;
14};
15
16static void slip_init(struct net_device *dev, void *data)
17{
18 struct uml_net_private *private;
19 struct slip_data *spri;
20 struct slip_init *init = data;
21
22 private = netdev_priv(dev);
23 spri = (struct slip_data *) private->user;
24
25 memset(spri->name, 0, sizeof(spri->name));
26 spri->addr = NULL;
27 spri->gate_addr = init->gate_addr;
28 spri->slave = -1;
29 spri->dev = dev;
30
31 slip_proto_init(slip: &spri->slip);
32
33 dev->hard_header_len = 0;
34 dev->header_ops = NULL;
35 dev->addr_len = 0;
36 dev->type = ARPHRD_SLIP;
37 dev->tx_queue_len = 256;
38 dev->flags = IFF_NOARP;
39 printk("SLIP backend - SLIP IP = %s\n", spri->gate_addr);
40}
41
42static unsigned short slip_protocol(struct sk_buff *skbuff)
43{
44 return htons(ETH_P_IP);
45}
46
47static int slip_read(int fd, struct sk_buff *skb, struct uml_net_private *lp)
48{
49 return slip_user_read(fd, buf: skb_mac_header(skb), len: skb->dev->mtu,
50 pri: (struct slip_data *) &lp->user);
51}
52
53static int slip_write(int fd, struct sk_buff *skb, struct uml_net_private *lp)
54{
55 return slip_user_write(fd, buf: skb->data, len: skb->len,
56 pri: (struct slip_data *) &lp->user);
57}
58
59static const struct net_kern_info slip_kern_info = {
60 .init = slip_init,
61 .protocol = slip_protocol,
62 .read = slip_read,
63 .write = slip_write,
64};
65
66static int slip_setup(char *str, char **mac_out, void *data)
67{
68 struct slip_init *init = data;
69
70 *init = ((struct slip_init) { .gate_addr = NULL });
71
72 if (str[0] != '\0')
73 init->gate_addr = str;
74 return 1;
75}
76
77static struct transport slip_transport = {
78 .list = LIST_HEAD_INIT(slip_transport.list),
79 .name = "slip",
80 .setup = slip_setup,
81 .user = &slip_user_info,
82 .kern = &slip_kern_info,
83 .private_size = sizeof(struct slip_data),
84 .setup_size = sizeof(struct slip_init),
85};
86
87static int register_slip(void)
88{
89 register_transport(&slip_transport);
90 return 0;
91}
92
93late_initcall(register_slip);
94

source code of linux/arch/um/drivers/slip_kern.c