arch/um/os-Linux/drivers/ethertap_user.c

   1 /*
   2  * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org) and
   4  * James Leu (jleu@mindspring.net).
   5  * Copyright (C) 2001 by various other people who didn't put their name here.
   6  * Licensed under the GPL.
   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
  24 static 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
  32 struct addr_change {
  33         enum { ADD_ADDR, DEL_ADDR } what;
  34         unsigned char addr[4];
  35         unsigned char netmask[4];
  36 };
  37
  38 static 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 = 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
  66 static 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
  72 static 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
  78 struct etap_pre_exec_data {
  79         int control_remote;
  80         int control_me;
  81         int data_me;
  82 };
  83
  84 static 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
  93 static 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, 0, "uml_net");
 135         }
 136         return err;
 137 }
 138
 139 static 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 = 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
 189 out_close_control:
 190         close(control_fds[0]);
 191         close(control_fds[1]);
 192 out_close_data:
 193         close(data_fds[0]);
 194         close(data_fds[1]);
 195         return err;
 196 }
 197
 198 static 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
 219 static 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
 230 static 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
 241 const 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 };