1
2
3
4
5
6
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 "kern_constants.h"
17#include "os.h"
18#include "net_user.h"
19#include "um_malloc.h"
20#include "user.h"
21
22#define MAX_PACKET ETH_MAX_PACKET
23
24static int etap_user_init(void *data, void *dev)
25{
26 struct ethertap_data *pri = data;
27
28 pri->dev = dev;
29 return 0;
30}
31
32struct addr_change {
33 enum { ADD_ADDR, DEL_ADDR } what;
34 unsigned char addr[4];
35 unsigned char netmask[4];
36};
37
38static void etap_change(int op, unsigned char *addr, unsigned char *netmask,
39 int fd)
40{
41 struct addr_change change;
42 char *output;
43 int n;
44
45 change.what = op;
46 memcpy(change.addr, addr, sizeof(change.addr));
47 memcpy(change.netmask, netmask, sizeof(change.netmask));
48 CATCH_EINTR(n = write(fd, &change, sizeof(change)));
49 if (n != sizeof(change)) {
50 printk(UM_KERN_ERR "etap_change - request failed, err = %d\n",
51 errno);
52 return;
53 }
54
55 output = uml_kmalloc(UM_KERN_PAGE_SIZE, UM_GFP_KERNEL);
56 if (output == NULL)
57 printk(UM_KERN_ERR "etap_change : Failed to allocate output "
58 "buffer\n");
59 read_output(fd, output, UM_KERN_PAGE_SIZE);
60 if (output != NULL) {
61 printk("%s", output);
62 kfree(output);
63 }
64}
65
66static void etap_open_addr(unsigned char *addr, unsigned char *netmask,
67 void *arg)
68{
69 etap_change(ADD_ADDR, addr, netmask, *((int *) arg));
70}
71
72static void etap_close_addr(unsigned char *addr, unsigned char *netmask,
73 void *arg)
74{
75 etap_change(DEL_ADDR, addr, netmask, *((int *) arg));
76}
77
78struct etap_pre_exec_data {
79 int control_remote;
80 int control_me;
81 int data_me;
82};
83
84static void etap_pre_exec(void *arg)
85{
86 struct etap_pre_exec_data *data = arg;
87
88 dup2(data->control_remote, 1);
89 close(data->data_me);
90 close(data->control_me);
91}
92
93static int etap_tramp(char *dev, char *gate, int control_me,
94 int control_remote, int data_me, int data_remote)
95{
96 struct etap_pre_exec_data pe_data;
97 int pid, err, n;
98 char version_buf[sizeof("nnnnn\0")];
99 char data_fd_buf[sizeof("nnnnnn\0")];
100 char gate_buf[sizeof("nnn.nnn.nnn.nnn\0")];
101 char *setup_args[] = { "uml_net", version_buf, "ethertap", dev,
102 data_fd_buf, gate_buf, NULL };
103 char *nosetup_args[] = { "uml_net", version_buf, "ethertap",
104 dev, data_fd_buf, NULL };
105 char **args, c;
106
107 sprintf(data_fd_buf, "%d", data_remote);
108 sprintf(version_buf, "%d", UML_NET_VERSION);
109 if (gate != NULL) {
110 strcpy(gate_buf, gate);
111 args = setup_args;
112 }
113 else args = nosetup_args;
114
115 err = 0;
116 pe_data.control_remote = control_remote;
117 pe_data.control_me = control_me;
118 pe_data.data_me = data_me;
119 pid = run_helper(etap_pre_exec, &pe_data, args);
120
121 if (pid < 0)
122 err = pid;
123 close(data_remote);
124 close(control_remote);
125 CATCH_EINTR(n = read(control_me, &c, sizeof(c)));
126 if (n != sizeof(c)) {
127 err = -errno;
128 printk(UM_KERN_ERR "etap_tramp : read of status failed, "
129 "err = %d\n", -err);
130 return err;
131 }
132 if (c != 1) {
133 printk(UM_KERN_ERR "etap_tramp : uml_net failed\n");
134 err = helper_wait(pid);
135 }
136 return err;
137}
138
139static int etap_open(void *data)
140{
141 struct ethertap_data *pri = data;
142 char *output;
143 int data_fds[2], control_fds[2], err, output_len;
144
145 err = tap_open_common(pri->dev, pri->gate_addr);
146 if (err)
147 return err;
148
149 err = socketpair(AF_UNIX, SOCK_DGRAM, 0, data_fds);
150 if (err) {
151 err = -errno;
152 printk(UM_KERN_ERR "etap_open - data socketpair failed - "
153 "err = %d\n", errno);
154 return err;
155 }
156
157 err = socketpair(AF_UNIX, SOCK_STREAM, 0, control_fds);
158 if (err) {
159 err = -errno;
160 printk(UM_KERN_ERR "etap_open - control socketpair failed - "
161 "err = %d\n", errno);
162 goto out_close_data;
163 }
164
165 err = etap_tramp(pri->dev_name, pri->gate_addr, control_fds[0],
166 control_fds[1], data_fds[0], data_fds[1]);
167 output_len = UM_KERN_PAGE_SIZE;
168 output = uml_kmalloc(output_len, UM_GFP_KERNEL);
169 read_output(control_fds[0], output, output_len);
170
171 if (output == NULL)
172 printk(UM_KERN_ERR "etap_open : failed to allocate output "
173 "buffer\n");
174 else {
175 printk("%s", output);
176 kfree(output);
177 }
178
179 if (err < 0) {
180 printk(UM_KERN_ERR "etap_tramp failed - err = %d\n", -err);
181 goto out_close_control;
182 }
183
184 pri->data_fd = data_fds[0];
185 pri->control_fd = control_fds[0];
186 iter_addresses(pri->dev, etap_open_addr, &pri->control_fd);
187 return data_fds[0];
188
189out_close_control:
190 close(control_fds[0]);
191 close(control_fds[1]);
192out_close_data:
193 close(data_fds[0]);
194 close(data_fds[1]);
195 return err;
196}
197
198static void etap_close(int fd, void *data)
199{
200 struct ethertap_data *pri = data;
201
202 iter_addresses(pri->dev, etap_close_addr, &pri->control_fd);
203 close(fd);
204
205 if (shutdown(pri->data_fd, SHUT_RDWR) < 0)
206 printk(UM_KERN_ERR "etap_close - shutdown data socket failed, "
207 "errno = %d\n", errno);
208
209 if (shutdown(pri->control_fd, SHUT_RDWR) < 0)
210 printk(UM_KERN_ERR "etap_close - shutdown control socket "
211 "failed, errno = %d\n", errno);
212
213 close(pri->data_fd);
214 pri->data_fd = -1;
215 close(pri->control_fd);
216 pri->control_fd = -1;
217}
218
219static void etap_add_addr(unsigned char *addr, unsigned char *netmask,
220 void *data)
221{
222 struct ethertap_data *pri = data;
223
224 tap_check_ips(pri->gate_addr, addr);
225 if (pri->control_fd == -1)
226 return;
227 etap_open_addr(addr, netmask, &pri->control_fd);
228}
229
230static void etap_del_addr(unsigned char *addr, unsigned char *netmask,
231 void *data)
232{
233 struct ethertap_data *pri = data;
234
235 if (pri->control_fd == -1)
236 return;
237
238 etap_close_addr(addr, netmask, &pri->control_fd);
239}
240
241const struct net_user_info ethertap_user_info = {
242 .init = etap_user_init,
243 .open = etap_open,
244 .close = etap_close,
245 .remove = NULL,
246 .add_address = etap_add_addr,
247 .delete_address = etap_del_addr,
248 .mtu = ETH_MAX_PACKET,
249 .max_packet = ETH_MAX_PACKET + ETH_HEADER_ETHERTAP,
250};
251
