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

   1 /*
   2  * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <stdio.h>
   7 #include <unistd.h>
   8 #include <errno.h>
   9 #include <string.h>
  10 #include <linux/if_tun.h>
  11 #include <net/if.h>
  12 #include <sys/ioctl.h>
  13 #include <sys/socket.h>
  14 #include <sys/wait.h>
  15 #include <sys/uio.h>
  16 #include "kern_constants.h"
  17 #include "kern_util.h"
  18 #include "os.h"
  19 #include "tuntap.h"
  20 #include "user.h"
  21
  22 static int tuntap_user_init(void *data, void *dev)
  23 {
  24         struct tuntap_data *pri = data;
  25
  26         pri->dev = dev;
  27         return 0;
  28 }
  29
  30 static void tuntap_add_addr(unsigned char *addr, unsigned char *netmask,
  31                             void *data)
  32 {
  33         struct tuntap_data *pri = data;
  34
  35         tap_check_ips(pri->gate_addr, addr);
  36         if ((pri->fd == -1) || pri->fixed_config)
  37                 return;
  38         open_addr(addr, netmask, pri->dev_name);
  39 }
  40
  41 static void tuntap_del_addr(unsigned char *addr, unsigned char *netmask,
  42                             void *data)
  43 {
  44         struct tuntap_data *pri = data;
  45
  46         if ((pri->fd == -1) || pri->fixed_config)
  47                 return;
  48         close_addr(addr, netmask, pri->dev_name);
  49 }
  50
  51 struct tuntap_pre_exec_data {
  52         int stdout;
  53         int close_me;
  54 };
  55
  56 static void tuntap_pre_exec(void *arg)
  57 {
  58         struct tuntap_pre_exec_data *data = arg;
  59
  60         dup2(data->stdout, 1);
  61         close(data->close_me);
  62 }
  63
  64 static int tuntap_open_tramp(char *gate, int *fd_out, int me, int remote,
  65                              char *buffer, int buffer_len, int *used_out)
  66 {
  67         struct tuntap_pre_exec_data data;
  68         char version_buf[sizeof("nnnnn\0")];
  69         char *argv[] = { "uml_net", version_buf, "tuntap", "up", gate,
  70                          NULL };
  71         char buf[CMSG_SPACE(sizeof(*fd_out))];
  72         struct msghdr msg;
  73         struct cmsghdr *cmsg;
  74         struct iovec iov;
  75         int pid, n, err;
  76
  77         sprintf(version_buf, "%d", UML_NET_VERSION);
  78
  79         data.stdout = remote;
  80         data.close_me = me;
  81
  82         pid = run_helper(tuntap_pre_exec, &data, argv);
  83
  84         if (pid < 0)
  85                 return -pid;
  86
  87         close(remote);
  88
  89         msg.msg_name = NULL;
  90         msg.msg_namelen = 0;
  91         if (buffer != NULL) {
  92                 iov = ((struct iovec) { buffer, buffer_len });
  93                 msg.msg_iov = &iov;
  94                 msg.msg_iovlen = 1;
  95         }
  96         else {
  97                 msg.msg_iov = NULL;
  98                 msg.msg_iovlen = 0;
  99         }
 100         msg.msg_control = buf;
 101         msg.msg_controllen = sizeof(buf);
 102         msg.msg_flags = 0;
 103         n = recvmsg(me, &msg, 0);
 104         *used_out = n;
 105         if (n < 0) {
 106                 err = -errno;
 107                 printk(UM_KERN_ERR "tuntap_open_tramp : recvmsg failed - "
 108                        "errno = %d\n", errno);
 109                 return err;
 110         }
 111         helper_wait(pid);
 112
 113         cmsg = CMSG_FIRSTHDR(&msg);
 114         if (cmsg == NULL) {
 115                 printk(UM_KERN_ERR "tuntap_open_tramp : didn't receive a "
 116                        "message\n");
 117                 return -EINVAL;
 118         }
 119         if ((cmsg->cmsg_level != SOL_SOCKET) ||
 120            (cmsg->cmsg_type != SCM_RIGHTS)) {
 121                 printk(UM_KERN_ERR "tuntap_open_tramp : didn't receive a "
 122                        "descriptor\n");
 123                 return -EINVAL;
 124         }
 125         *fd_out = ((int *) CMSG_DATA(cmsg))[0];
 126         os_set_exec_close(*fd_out);
 127         return 0;
 128 }
 129
 130 static int tuntap_open(void *data)
 131 {
 132         struct ifreq ifr;
 133         struct tuntap_data *pri = data;
 134         char *output, *buffer;
 135         int err, fds[2], len, used;
 136
 137         err = tap_open_common(pri->dev, pri->gate_addr);
 138         if (err < 0)
 139                 return err;
 140
 141         if (pri->fixed_config) {
 142                 pri->fd = os_open_file("/dev/net/tun",
 143                                        of_cloexec(of_rdwr(OPENFLAGS())), 0);
 144                 if (pri->fd < 0) {
 145                         printk(UM_KERN_ERR "Failed to open /dev/net/tun, "
 146                                "err = %d\n", -pri->fd);
 147                         return pri->fd;
 148                 }
 149                 memset(&ifr, 0, sizeof(ifr));
 150                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
 151                 strlcpy(ifr.ifr_name, pri->dev_name, sizeof(ifr.ifr_name));
 152                 if (ioctl(pri->fd, TUNSETIFF, &ifr) < 0) {
 153                         err = -errno;
 154                         printk(UM_KERN_ERR "TUNSETIFF failed, errno = %d\n",
 155                                errno);
 156                         close(pri->fd);
 157                         return err;
 158                 }
 159         }
 160         else {
 161                 err = socketpair(AF_UNIX, SOCK_DGRAM, 0, fds);
 162                 if (err) {
 163                         err = -errno;
 164                         printk(UM_KERN_ERR "tuntap_open : socketpair failed - "
 165                                "errno = %d\n", errno);
 166                         return err;
 167                 }
 168
 169                 buffer = get_output_buffer(&len);
 170                 if (buffer != NULL)
 171                         len--;
 172                 used = 0;
 173
 174                 err = tuntap_open_tramp(pri->gate_addr, &pri->fd, fds[0],
 175                                         fds[1], buffer, len, &used);
 176
 177                 output = buffer;
 178                 if (err < 0) {
 179                         printk("%s", output);
 180                         free_output_buffer(buffer);
 181                         printk(UM_KERN_ERR "tuntap_open_tramp failed - "
 182                                "err = %d\n", -err);
 183                         return err;
 184                 }
 185
 186                 pri->dev_name = uml_strdup(buffer);
 187                 output += IFNAMSIZ;
 188                 printk("%s", output);
 189                 free_output_buffer(buffer);
 190
 191                 close(fds[0]);
 192                 iter_addresses(pri->dev, open_addr, pri->dev_name);
 193         }
 194
 195         return pri->fd;
 196 }
 197
 198 static void tuntap_close(int fd, void *data)
 199 {
 200         struct tuntap_data *pri = data;
 201
 202         if (!pri->fixed_config)
 203                 iter_addresses(pri->dev, close_addr, pri->dev_name);
 204         close(fd);
 205         pri->fd = -1;
 206 }
 207
 208 const struct net_user_info tuntap_user_info = {
 209         .init           = tuntap_user_init,
 210         .open           = tuntap_open,
 211         .close          = tuntap_close,
 212         .remove         = NULL,
 213         .add_address    = tuntap_add_addr,
 214         .delete_address = tuntap_del_addr,
 215         .mtu            = ETH_MAX_PACKET,
 216         .max_packet     = ETH_MAX_PACKET + ETH_HEADER_OTHER,
 217 };