Support utun devices on Mac OS X.

As of 10.6, OS X has native tunnel devices. They are implemented as
sockets rather than character devices, but otherwise they appear to
behave the same as Free/OpenBSD tunnels.

'-d utunX' will tell iodine to use a utun device. For backward
compatibility, we'll continue to default to the old tuntap devices for
now.

This is a port of Peter Sagerson <psagers.github@ignorare.net>'s openvpn
commit 43e5016a.
This commit is contained in:
Catalin Patulea 2015-03-05 13:06:23 -08:00
parent 1160649794
commit 33abc0ca26
1 changed files with 143 additions and 25 deletions

168
src/tun.c
View File

@ -1,6 +1,7 @@
/* /*
* Copyright (c) 2006-2014 Erik Ekman <yarrick@kryo.se>, * Copyright (c) 2006-2014 Erik Ekman <yarrick@kryo.se>,
* 2006-2009 Bjorn Andersson <flex@kryo.se> * 2006-2009 Bjorn Andersson <flex@kryo.se>
* 2013 Peter Sagerson <psagers.github@ignorare.net>
* *
* Permission to use, copy, modify, and/or distribute this software for any * Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above * purpose with or without fee is hereby granted, provided that the above
@ -25,6 +26,15 @@
#include <sys/stat.h> #include <sys/stat.h>
#include <fcntl.h> #include <fcntl.h>
#ifdef DARWIN
#include <ctype.h>
#include <sys/kern_control.h>
#include <sys/sys_domain.h>
#include <sys/ioctl.h>
#include <net/if_utun.h>
#include <netinet/ip.h>
#endif
#ifndef IFCONFIGPATH #ifndef IFCONFIGPATH
#define IFCONFIGPATH "PATH=/sbin:/bin " #define IFCONFIGPATH "PATH=/sbin:/bin "
#endif #endif
@ -315,6 +325,86 @@ open_tun(const char *tun_device)
#else /* BSD and friends */ #else /* BSD and friends */
#ifdef DARWIN
/* Extract the device number from the name, if given. The value returned will
* be suitable for sockaddr_ctl.sc_unit, which means 0 for auto-assign, or
* (n + 1) for manual.
*/
static int
utun_unit(const char *dev)
{
const char *unit_str = dev;
int unit = 0;
while (*unit_str != '\0' && !isdigit(*unit_str))
unit_str++;
if (isdigit(*unit_str))
unit = strtol(unit_str, NULL, 10) + 1;
return unit;
}
static int
open_utun(const char *dev)
{
struct sockaddr_ctl addr;
struct ctl_info info;
char ifname[10];
socklen_t ifname_len = sizeof(ifname);
int fd = -1;
int err = 0;
fd = socket(PF_SYSTEM, SOCK_DGRAM, SYSPROTO_CONTROL);
if (fd < 0) {
warn("open_utun: socket(PF_SYSTEM)");
return -1;
}
/* Look up the kernel controller ID for utun devices. */
bzero(&info, sizeof(info));
strncpy(info.ctl_name, UTUN_CONTROL_NAME, MAX_KCTL_NAME);
err = ioctl(fd, CTLIOCGINFO, &info);
if (err != 0) {
warn("open_utun: ioctl(CTLIOCGINFO)");
close(fd);
return -1;
}
/* Connecting to the socket creates the utun device. */
addr.sc_len = sizeof(addr);
addr.sc_family = AF_SYSTEM;
addr.ss_sysaddr = AF_SYS_CONTROL;
addr.sc_id = info.ctl_id;
addr.sc_unit = utun_unit(dev);
err = connect(fd, (struct sockaddr *)&addr, sizeof(addr));
if (err != 0) {
warn("open_utun: connect");
close(fd);
return -1;
}
/* Retrieve the assigned interface name. */
err = getsockopt(fd, SYSPROTO_CONTROL, UTUN_OPT_IFNAME, ifname, &ifname_len);
if (err != 0) {
warn("open_utun: getsockopt(UTUN_OPT_IFNAME)");
close(fd);
return -1;
}
strncpy(if_name, ifname, sizeof(if_name));
fprintf(stderr, "Opened %s\n", ifname);
fd_set_close_on_exec(fd);
return fd;
}
#endif
int int
open_tun(const char *tun_device) open_tun(const char *tun_device)
{ {
@ -322,6 +412,15 @@ open_tun(const char *tun_device)
int tun_fd; int tun_fd;
char tun_name[50]; char tun_name[50];
#ifdef DARWIN
if (!strncmp(tun_device, "utun", 4)) {
tun_fd = open_utun(tun_device);
if (tun_fd >= 0) {
return tun_fd;
}
}
#endif
if (tun_device != NULL) { if (tun_device != NULL) {
snprintf(tun_name, sizeof(tun_name), "/dev/%s", tun_device); snprintf(tun_name, sizeof(tun_name), "/dev/%s", tun_device);
strncpy(if_name, tun_device, sizeof(if_name)); strncpy(if_name, tun_device, sizeof(if_name));
@ -407,22 +506,32 @@ read_tun(int tun_fd, char *buf, size_t len)
int int
write_tun(int tun_fd, char *data, size_t len) write_tun(int tun_fd, char *data, size_t len)
{ {
#if defined (FREEBSD) || defined (DARWIN) || defined(NETBSD) #if defined (FREEBSD) || defined (NETBSD)
data += 4; /* FreeBSD/NetBSD has no header */
len -= 4; int header = 0;
#else /* !FREEBSD/DARWIN */ #elif defined (DARWIN)
/* Darwin tun has no header, Darwin utun does */
int header = !strncmp(if_name, "utun", 4);
#else /* LINUX/OPENBSD */
int header = 1;
#endif
if (!header) {
data += 4;
len -= 4;
} else {
#ifdef LINUX #ifdef LINUX
data[0] = 0x00; data[0] = 0x00;
data[1] = 0x00; data[1] = 0x00;
data[2] = 0x08; data[2] = 0x08;
data[3] = 0x00; data[3] = 0x00;
#else /* OPENBSD */ #else /* OPENBSD */
data[0] = 0x00; data[0] = 0x00;
data[1] = 0x00; data[1] = 0x00;
data[2] = 0x00; data[2] = 0x00;
data[3] = 0x02; data[3] = 0x02;
#endif /* !LINUX */ #endif
#endif /* FREEBSD */ }
if (write(tun_fd, data, len) != len) { if (write(tun_fd, data, len) != len) {
warn("write_tun"); warn("write_tun");
@ -434,20 +543,29 @@ write_tun(int tun_fd, char *data, size_t len)
ssize_t ssize_t
read_tun(int tun_fd, char *buf, size_t len) read_tun(int tun_fd, char *buf, size_t len)
{ {
#if defined (FREEBSD) || defined (DARWIN) || defined(NETBSD) #if defined (FREEBSD) || defined (NETBSD)
/* FreeBSD/Darwin/NetBSD has no header */ /* FreeBSD/NetBSD has no header */
int bytes; int header = 0;
memset(buf, 0, 4); #elif defined (DARWIN)
/* Darwin tun has no header, Darwin utun does */
int header = !strncmp(if_name, "utun", 4);
#else /* LINUX/OPENBSD */
int header = 1;
#endif
bytes = read(tun_fd, buf + 4, len - 4); if (!header) {
if (bytes < 0) { int bytes;
return bytes; memset(buf, 0, 4);
bytes = read(tun_fd, buf + 4, len - 4);
if (bytes < 0) {
return bytes;
} else {
return bytes + 4;
}
} else { } else {
return bytes + 4; return read(tun_fd, buf, len);
} }
#else /* !FREEBSD */
return read(tun_fd, buf, len);
#endif /* !FREEBSD */
} }
#endif #endif