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

   1 /*
   2  * Copyright (C) 2001, 2002 Jeff Dike (jdike@karaya.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <stdio.h>
   7 #include <stddef.h>
   8 #include <stdlib.h>
   9 #include <unistd.h>
  10 #include <errno.h>
  11 #include <sys/wait.h>
  12 #include <sys/socket.h>
  13 #include <sys/un.h>
  14 #include <sys/uio.h>
  15 #include <sys/ioctl.h>
  16 #include <net/if.h>
  17 #include <linux/if_tun.h>
  18 #include "net_user.h"
  19 #include "tuntap.h"
  20 #include "kern_util.h"
  21 #include "user_util.h"
  22 #include "user.h"
  23 #include "os.h"
  24
  25 #define MAX_PACKET ETH_MAX_PACKET
  26
  27 static int tuntap_user_init(void *data, void *dev)
  28 {
  29         struct tuntap_data *pri = data;
  30
  31         pri->dev = dev;
  32         return 0;
  33 }
  34
  35 static void tuntap_add_addr(unsigned char *addr, unsigned char *netmask,
  36                             void *data)
  37 {
  38         struct tuntap_data *pri = data;
  39
  40         tap_check_ips(pri->gate_addr, addr);
  41         if((pri->fd == -1) || pri->fixed_config)
  42                 return;
  43         open_addr(addr, netmask, pri->dev_name);
  44 }
  45
  46 static void tuntap_del_addr(unsigned char *addr, unsigned char *netmask,
  47                             void *data)
  48 {
  49         struct tuntap_data *pri = data;
  50
  51         if((pri->fd == -1) || pri->fixed_config)
  52                 return;
  53         close_addr(addr, netmask, pri->dev_name);
  54 }
  55
  56 struct tuntap_pre_exec_data {
  57         int stdout;
  58         int close_me;
  59 };
  60
  61 static void tuntap_pre_exec(void *arg)
  62 {
  63         struct tuntap_pre_exec_data *data = arg;
  64
  65         dup2(data->stdout, 1);
  66         os_close_file(data->close_me);
  67 }
  68
  69 static int tuntap_open_tramp(char *gate, int *fd_out, int me, int remote,
  70                              char *buffer, int buffer_len, int *used_out)
  71 {
  72         struct tuntap_pre_exec_data data;
  73         char version_buf[sizeof("nnnnn\0")];
  74         char *argv[] = { "uml_net", version_buf, "tuntap", "up", gate,
  75                          NULL };
  76         char buf[CMSG_SPACE(sizeof(*fd_out))];
  77         struct msghdr msg;
  78         struct cmsghdr *cmsg;
  79         struct iovec iov;
  80         int pid, n, err;
  81
  82         sprintf(version_buf, "%d", UML_NET_VERSION);
  83
  84         data.stdout = remote;
  85         data.close_me = me;
  86
  87         pid = run_helper(tuntap_pre_exec, &data, argv, NULL);
  88
  89         if(pid < 0)
  90                 return -pid;
  91
  92         os_close_file(remote);
  93
  94         msg.msg_name = NULL;
  95         msg.msg_namelen = 0;
  96         if(buffer != NULL){
  97                 iov = ((struct iovec) { buffer, buffer_len });
  98                 msg.msg_iov = &iov;
  99                 msg.msg_iovlen = 1;
 100         }
 101         else {
 102                 msg.msg_iov = NULL;
 103                 msg.msg_iovlen = 0;
 104         }
 105         msg.msg_control = buf;
 106         msg.msg_controllen = sizeof(buf);
 107         msg.msg_flags = 0;
 108         n = recvmsg(me, &msg, 0);
 109         *used_out = n;
 110         if(n < 0){
 111                 err = -errno;
 112                 printk("tuntap_open_tramp : recvmsg failed - errno = %d\n",
 113                        errno);
 114                 return err;
 115         }
 116         CATCH_EINTR(waitpid(pid, NULL, 0));
 117
 118         cmsg = CMSG_FIRSTHDR(&msg);
 119         if(cmsg == NULL){
 120                 printk("tuntap_open_tramp : didn't receive a message\n");
 121                 return -EINVAL;
 122         }
 123         if((cmsg->cmsg_level != SOL_SOCKET) ||
 124            (cmsg->cmsg_type != SCM_RIGHTS)){
 125                 printk("tuntap_open_tramp : didn't receive a descriptor\n");
 126                 return -EINVAL;
 127         }
 128         *fd_out = ((int *) CMSG_DATA(cmsg))[0];
 129         os_set_exec_close(*fd_out, 1);
 130         return 0;
 131 }
 132
 133 static int tuntap_open(void *data)
 134 {
 135         struct ifreq ifr;
 136         struct tuntap_data *pri = data;
 137         char *output, *buffer;
 138         int err, fds[2], len, used;
 139
 140         err = tap_open_common(pri->dev, pri->gate_addr);
 141         if(err < 0)
 142                 return err;
 143
 144         if(pri->fixed_config){
 145                 pri->fd = os_open_file("/dev/net/tun",
 146                                        of_cloexec(of_rdwr(OPENFLAGS())), 0);
 147                 if(pri->fd < 0){
 148                         printk("Failed to open /dev/net/tun, err = %d\n",
 149                                -pri->fd);
 150                         return pri->fd;
 151                 }
 152                 memset(&ifr, 0, sizeof(ifr));
 153                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
 154                 strlcpy(ifr.ifr_name, pri->dev_name, sizeof(ifr.ifr_name));
 155                 if(ioctl(pri->fd, TUNSETIFF, (void *) &ifr) < 0){
 156                         err = -errno;
 157                         printk("TUNSETIFF failed, errno = %d\n", errno);
 158                         os_close_file(pri->fd);
 159                         return err;
 160                 }
 161         }
 162         else {
 163                 err = os_pipe(fds, 0, 0);
 164                 if(err < 0){
 165                         printk("tuntap_open : os_pipe failed - err = %d\n",
 166                                -err);
 167                         return err;
 168                 }
 169
 170                 buffer = get_output_buffer(&len);
 171                 if(buffer != NULL) 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("tuntap_open_tramp failed - 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                 os_close_file(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         os_close_file(fd);
 204         pri->fd = -1;
 205 }
 206
 207 static int tuntap_set_mtu(int mtu, void *data)
 208 {
 209         return mtu;
 210 }
 211
 212 const struct net_user_info tuntap_user_info = {
 213         .init           = tuntap_user_init,
 214         .open           = tuntap_open,
 215         .close          = tuntap_close,
 216         .remove         = NULL,
 217         .set_mtu        = tuntap_set_mtu,
 218         .add_address    = tuntap_add_addr,
 219         .delete_address = tuntap_del_addr,
 220         .max_packet     = MAX_PACKET
 221 };