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