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 #define MAX_PACKET ETH_MAX_PACKET
  22
  23 static int tuntap_user_init(void *data, void *dev)
  24 {
  25         struct tuntap_data *pri = data;
  26
  27         pri->dev = dev;
  28         return 0;
  29 }
  30
  31 static void tuntap_add_addr(unsigned char *addr, unsigned char *netmask,
  32                             void *data)
  33 {
  34         struct tuntap_data *pri = data;
  35
  36         tap_check_ips(pri->gate_addr, addr);
  37         if ((pri->fd == -1) || pri->fixed_config)
  38                 return;
  39         open_addr(addr, netmask, pri->dev_name);
  40 }
  41
  42 static void tuntap_del_addr(unsigned char *addr, unsigned char *netmask,
  43                             void *data)
  44 {
  45         struct tuntap_data *pri = data;
  46
  47         if ((pri->fd == -1) || pri->fixed_config)
  48                 return;
  49         close_addr(addr, netmask, pri->dev_name);
  50 }
  51
  52 struct tuntap_pre_exec_data {
  53         int stdout;
  54         int close_me;
  55 };
  56
  57 static void tuntap_pre_exec(void *arg)
  58 {
  59         struct tuntap_pre_exec_data *data = arg;
  60
  61         dup2(data->stdout, 1);
  62         close(data->close_me);
  63 }
  64
  65 static int tuntap_open_tramp(char *gate, int *fd_out, int me, int remote,
  66                              char *buffer, int buffer_len, int *used_out)
  67 {
  68         struct tuntap_pre_exec_data data;
  69         char version_buf[sizeof("nnnnn\0")];
  70         char *argv[] = { "uml_net", version_buf, "tuntap", "up", gate,
  71                          NULL };
  72         char buf[CMSG_SPACE(sizeof(*fd_out))];
  73         struct msghdr msg;
  74         struct cmsghdr *cmsg;
  75         struct iovec iov;
  76         int pid, n, err;
  77
  78         sprintf(version_buf, "%d", UML_NET_VERSION);
  79
  80         data.stdout = remote;
  81         data.close_me = me;
  82
  83         pid = run_helper(tuntap_pre_exec, &data, argv);
  84
  85         if (pid < 0)
  86                 return -pid;
  87
  88         close(remote);
  89
  90         msg.msg_name = NULL;
  91         msg.msg_namelen = 0;
  92         if (buffer != NULL) {
  93                 iov = ((struct iovec) { buffer, buffer_len });
  94                 msg.msg_iov = &iov;
  95                 msg.msg_iovlen = 1;
  96         }
  97         else {
  98                 msg.msg_iov = NULL;
  99                 msg.msg_iovlen = 0;
 100         }
 101         msg.msg_control = buf;
 102         msg.msg_controllen = sizeof(buf);
 103         msg.msg_flags = 0;
 104         n = recvmsg(me, &msg, 0);
 105         *used_out = n;
 106         if (n < 0) {
 107                 err = -errno;
 108                 printk(UM_KERN_ERR "tuntap_open_tramp : recvmsg failed - "
 109                        "errno = %d\n", errno);
 110                 return err;
 111         }
 112         CATCH_EINTR(waitpid(pid, NULL, 0));
 113
 114         cmsg = CMSG_FIRSTHDR(&msg);
 115         if (cmsg == NULL) {
 116                 printk(UM_KERN_ERR "tuntap_open_tramp : didn't receive a "
 117                        "message\n");
 118                 return -EINVAL;
 119         }
 120         if ((cmsg->cmsg_level != SOL_SOCKET) ||
 121            (cmsg->cmsg_type != SCM_RIGHTS)) {
 122                 printk(UM_KERN_ERR "tuntap_open_tramp : didn't receive a "
 123                        "descriptor\n");
 124                 return -EINVAL;
 125         }
 126         *fd_out = ((int *) CMSG_DATA(cmsg))[0];
 127         os_set_exec_close(*fd_out);
 128         return 0;
 129 }
 130
 131 static int tuntap_open(void *data)
 132 {
 133         struct ifreq ifr;
 134         struct tuntap_data *pri = data;
 135         char *output, *buffer;
 136         int err, fds[2], len, used;
 137
 138         err = tap_open_common(pri->dev, pri->gate_addr);
 139         if (err < 0)
 140                 return err;
 141
 142         if (pri->fixed_config) {
 143                 pri->fd = os_open_file("/dev/net/tun",
 144                                        of_cloexec(of_rdwr(OPENFLAGS())), 0);
 145                 if (pri->fd < 0) {
 146                         printk(UM_KERN_ERR "Failed to open /dev/net/tun, "
 147                                "err = %d\n", -pri->fd);
 148                         return pri->fd;
 149                 }
 150                 memset(&ifr, 0, sizeof(ifr));
 151                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
 152                 strlcpy(ifr.ifr_name, pri->dev_name, sizeof(ifr.ifr_name));
 153                 if (ioctl(pri->fd, TUNSETIFF, (void *) &ifr) < 0) {
 154                         err = -errno;
 155                         printk(UM_KERN_ERR "TUNSETIFF failed, errno = %d\n",
 156                                errno);
 157                         close(pri->fd);
 158                         return err;
 159                 }
 160         }
 161         else {
 162                 err = socketpair(AF_UNIX, SOCK_DGRAM, 0, fds);
 163                 if (err) {
 164                         err = -errno;
 165                         printk(UM_KERN_ERR "tuntap_open : socketpair failed - "
 166                                "errno = %d\n", errno);
 167                         return err;
 168                 }
 169
 170                 buffer = get_output_buffer(&len);
 171                 if (buffer != NULL)
 172                         len--;
 173                 used = 0;
 174
 175                 err = tuntap_open_tramp(pri->gate_addr, &pri->fd, fds[0],
 176                                         fds[1], buffer, len, &used);
 177
 178                 output = buffer;
 179                 if (err < 0) {
 180                         printk("%s", output);
 181                         free_output_buffer(buffer);
 182                         printk(UM_KERN_ERR "tuntap_open_tramp failed - "
 183                                "err = %d\n", -err);
 184                         return err;
 185                 }
 186
 187                 pri->dev_name = uml_strdup(buffer);
 188                 output += IFNAMSIZ;
 189                 printk("%s", output);
 190                 free_output_buffer(buffer);
 191
 192                 close(fds[0]);
 193                 iter_addresses(pri->dev, open_addr, pri->dev_name);
 194         }
 195
 196         return pri->fd;
 197 }
 198
 199 static void tuntap_close(int fd, void *data)
 200 {
 201         struct tuntap_data *pri = data;
 202
 203         if (!pri->fixed_config)
 204                 iter_addresses(pri->dev, close_addr, pri->dev_name);
 205         close(fd);
 206         pri->fd = -1;
 207 }
 208
 209 static int tuntap_set_mtu(int mtu, void *data)
 210 {
 211         return mtu;
 212 }
 213
 214 const struct net_user_info tuntap_user_info = {
 215         .init           = tuntap_user_init,
 216         .open           = tuntap_open,
 217         .close          = tuntap_close,
 218         .remove         = NULL,
 219         .set_mtu        = tuntap_set_mtu,
 220         .add_address    = tuntap_add_addr,
 221         .delete_address = tuntap_del_addr,
 222         .max_packet     = MAX_PACKET
 223 };