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
22 static 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
30 struct addr_change {
31 enum { ADD_ADDR, DEL_ADDR } what;
32 unsigned char addr[4];
33 unsigned char netmask[4];
34 };
35
36 static 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
64 static 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
70 static 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
76 struct etap_pre_exec_data {
77 int control_remote;
78 int control_me;
79 int data_me;
80 };
81
82 static 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
91 static 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
137 static 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
187 out_close_control:
188 close(control_fds[0]);
189 close(control_fds[1]);
190 out_close_data:
191 close(data_fds[0]);
192 close(data_fds[1]);
193 return err;
194 }
195
196 static 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
217 static 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
228 static 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
239 const 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
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