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