1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org) and
5 * James Leu (jleu@mindspring.net).
6 * Copyright (C) 2001 by various other people who didn't put their name here.
7 */
8
9#include <stdio.h>
10#include <unistd.h>
11#include <errno.h>
12#include <string.h>
13#include <sys/socket.h>
14#include <sys/wait.h>
15#include "etap.h"
16#include <os.h>
17#include <net_user.h>
18#include <um_malloc.h>
19
20#define MAX_PACKET ETH_MAX_PACKET
21
22static int etap_user_init(void *data, void *dev)
23{
24	struct ethertap_data *pri = data;
25
26	pri->dev = dev;
27	return 0;
28}
29
30struct addr_change {
31	enum { ADD_ADDR, DEL_ADDR } what;
32	unsigned char addr[4];
33	unsigned char netmask[4];
34};
35
36static void etap_change(int op, unsigned char *addr, unsigned char *netmask,
37			int fd)
38{
39	struct addr_change change;
40	char *output;
41	int n;
42
43	change.what = op;
44	memcpy(change.addr, addr, sizeof(change.addr));
45	memcpy(change.netmask, netmask, sizeof(change.netmask));
46	CATCH_EINTR(n = write(fd, &change, sizeof(change)));
47	if (n != sizeof(change)) {
48		printk(UM_KERN_ERR "etap_change - request failed, err = %d\n",
49		       errno);
50		return;
51	}
52
53	output = uml_kmalloc(UM_KERN_PAGE_SIZE, UM_GFP_KERNEL);
54	if (output == NULL)
55		printk(UM_KERN_ERR "etap_change : Failed to allocate output "
56		       "buffer\n");
57	read_output(fd, output, UM_KERN_PAGE_SIZE);
58	if (output != NULL) {
59		printk("%s", output);
60		kfree(output);
61	}
62}
63
64static void etap_open_addr(unsigned char *addr, unsigned char *netmask,
65			   void *arg)
66{
67	etap_change(ADD_ADDR, addr, netmask, *((int *) arg));
68}
69
70static void etap_close_addr(unsigned char *addr, unsigned char *netmask,
71			    void *arg)
72{
73	etap_change(DEL_ADDR, addr, netmask, *((int *) arg));
74}
75
76struct etap_pre_exec_data {
77	int control_remote;
78	int control_me;
79	int data_me;
80};
81
82static void etap_pre_exec(void *arg)
83{
84	struct etap_pre_exec_data *data = arg;
85
86	dup2(data->control_remote, 1);
87	close(data->data_me);
88	close(data->control_me);
89}
90
91static int etap_tramp(char *dev, char *gate, int control_me,
92		      int control_remote, int data_me, int data_remote)
93{
94	struct etap_pre_exec_data pe_data;
95	int pid, err, n;
96	char version_buf[sizeof("nnnnn\0")];
97	char data_fd_buf[sizeof("nnnnnn\0")];
98	char gate_buf[sizeof("nnn.nnn.nnn.nnn\0")];
99	char *setup_args[] = { "uml_net", version_buf, "ethertap", dev,
100			       data_fd_buf, gate_buf, NULL };
101	char *nosetup_args[] = { "uml_net", version_buf, "ethertap",
102				 dev, data_fd_buf, NULL };
103	char **args, c;
104
105	sprintf(data_fd_buf, "%d", data_remote);
106	sprintf(version_buf, "%d", UML_NET_VERSION);
107	if (gate != NULL) {
108		strscpy(gate_buf, gate);
109		args = setup_args;
110	}
111	else args = nosetup_args;
112
113	err = 0;
114	pe_data.control_remote = control_remote;
115	pe_data.control_me = control_me;
116	pe_data.data_me = data_me;
117	pid = run_helper(etap_pre_exec, &pe_data, args);
118
119	if (pid < 0)
120		err = pid;
121	close(data_remote);
122	close(control_remote);
123	CATCH_EINTR(n = read(control_me, &c, sizeof(c)));
124	if (n != sizeof(c)) {
125		err = -errno;
126		printk(UM_KERN_ERR "etap_tramp : read of status failed, "
127		       "err = %d\n", -err);
128		return err;
129	}
130	if (c != 1) {
131		printk(UM_KERN_ERR "etap_tramp : uml_net failed\n");
132		err = helper_wait(pid);
133	}
134	return err;
135}
136
137static int etap_open(void *data)
138{
139	struct ethertap_data *pri = data;
140	char *output;
141	int data_fds[2], control_fds[2], err, output_len;
142
143	err = tap_open_common(pri->dev, pri->gate_addr);
144	if (err)
145		return err;
146
147	err = socketpair(AF_UNIX, SOCK_DGRAM, 0, data_fds);
148	if (err) {
149		err = -errno;
150		printk(UM_KERN_ERR "etap_open - data socketpair failed - "
151		       "err = %d\n", errno);
152		return err;
153	}
154
155	err = socketpair(AF_UNIX, SOCK_STREAM, 0, control_fds);
156	if (err) {
157		err = -errno;
158		printk(UM_KERN_ERR "etap_open - control socketpair failed - "
159		       "err = %d\n", errno);
160		goto out_close_data;
161	}
162
163	err = etap_tramp(pri->dev_name, pri->gate_addr, control_fds[0],
164			 control_fds[1], data_fds[0], data_fds[1]);
165	output_len = UM_KERN_PAGE_SIZE;
166	output = uml_kmalloc(output_len, UM_GFP_KERNEL);
167	read_output(control_fds[0], output, output_len);
168
169	if (output == NULL)
170		printk(UM_KERN_ERR "etap_open : failed to allocate output "
171		       "buffer\n");
172	else {
173		printk("%s", output);
174		kfree(output);
175	}
176
177	if (err < 0) {
178		printk(UM_KERN_ERR "etap_tramp failed - err = %d\n", -err);
179		goto out_close_control;
180	}
181
182	pri->data_fd = data_fds[0];
183	pri->control_fd = control_fds[0];
184	iter_addresses(pri->dev, etap_open_addr, &pri->control_fd);
185	return data_fds[0];
186
187out_close_control:
188	close(control_fds[0]);
189	close(control_fds[1]);
190out_close_data:
191	close(data_fds[0]);
192	close(data_fds[1]);
193	return err;
194}
195
196static void etap_close(int fd, void *data)
197{
198	struct ethertap_data *pri = data;
199
200	iter_addresses(pri->dev, etap_close_addr, &pri->control_fd);
201	close(fd);
202
203	if (shutdown(pri->data_fd, SHUT_RDWR) < 0)
204		printk(UM_KERN_ERR "etap_close - shutdown data socket failed, "
205		       "errno = %d\n", errno);
206
207	if (shutdown(pri->control_fd, SHUT_RDWR) < 0)
208		printk(UM_KERN_ERR "etap_close - shutdown control socket "
209		       "failed, errno = %d\n", errno);
210
211	close(pri->data_fd);
212	pri->data_fd = -1;
213	close(pri->control_fd);
214	pri->control_fd = -1;
215}
216
217static void etap_add_addr(unsigned char *addr, unsigned char *netmask,
218			  void *data)
219{
220	struct ethertap_data *pri = data;
221
222	tap_check_ips(pri->gate_addr, addr);
223	if (pri->control_fd == -1)
224		return;
225	etap_open_addr(addr, netmask, &pri->control_fd);
226}
227
228static void etap_del_addr(unsigned char *addr, unsigned char *netmask,
229			  void *data)
230{
231	struct ethertap_data *pri = data;
232
233	if (pri->control_fd == -1)
234		return;
235
236	etap_close_addr(addr, netmask, &pri->control_fd);
237}
238
239const struct net_user_info ethertap_user_info = {
240	.init		= etap_user_init,
241	.open		= etap_open,
242	.close	 	= etap_close,
243	.remove	 	= NULL,
244	.add_address	= etap_add_addr,
245	.delete_address = etap_del_addr,
246	.mtu		= ETH_MAX_PACKET,
247	.max_packet	= ETH_MAX_PACKET + ETH_HEADER_ETHERTAP,
248};
249