Add m4/pkg.m4

Avoid pointer arithmetic on void *

.gitignore

@@ -1,9 +1,9 @@
 *.o
 *.log
 *.scan
-*.m4
 *.cache
 *.status
+aclocal.m4
 Makefile
 Makefile.in
 configure

Makefile.am

@@ -1,4 +1,22 @@
+ACLOCAL_AMFLAGS = -I m4 --install
+
 bin_PROGRAMS = glorytun
-glorytun_SOURCES = src/common.h src/common-static.h src/main.c src/option.c src/option.h
+
 glorytun_CFLAGS = $(libsodium_CFLAGS)
 glorytun_LDADD = $(libsodium_LIBS)
+glorytun_SOURCES = \
+    src/common.h \
+    src/common-static.h \
+    src/common.c \
+    src/ip-static.h \
+    src/main.c \
+    src/option.c \
+    src/option.h \
+    src/tun.c \
+    src/tun.h
+
+EXTRA_DIST = \
+	LICENSE \
+	README.md \
+	autogen.sh \
+	version.sh

README.md

@@ -1,8 +1,10 @@
-# glorytun
+# Glorytun
 
-**Work In Progress:** Do not touch!
+Small, Simple and Stupid **TCP** VPN.
 
-glorytun depends on [libsodium](https://github.com/jedisct1/libsodium) version >= 1.0.4
+**Work In Progress:** Do not touch! This code will probably format your harddisk!
+
+Glorytun depends on [libsodium](https://github.com/jedisct1/libsodium) version >= 1.0.4
 and needs an AES-NI capable CPU.
 
 To build and install the latest version:
@@ -16,5 +18,5 @@ To build and install the latest version:
 
 To create and use a new secret key:
 
-    $ dd if=/dev/random iflag=fullblock of=glorytun.key bs=32 count=1
+    $ dd if=/dev/urandom of=glorytun.key bs=32 count=1
     # glorytun keyfile glorytun.key [...]

autogen.sh

@@ -1,2 +1,3 @@
 #!/bin/sh
+
 autoreconf -i -f

configure.ac

@@ -1,11 +1,16 @@
 AC_PREREQ([2.65])
-AC_INIT([glorytun], [0.0.1], [https://github.com/angt/glorytun/issues],
+AC_INIT([glorytun],
-        [glorytun], [https://github.com/angt/glorytun])
+        [m4_esyscmd([./version.sh])],
+        [https://github.com/angt/glorytun/issues],
+        [glorytun],
+        [https://github.com/angt/glorytun])
 AC_CONFIG_SRCDIR([src/common.h])
 AC_CONFIG_AUX_DIR([build-aux])
+AC_CONFIG_MACRO_DIR([m4])
 AM_INIT_AUTOMAKE([1.9 -Wall -Werror foreign tar-ustar subdir-objects])
 AM_DEP_TRACK
 AM_SILENT_RULES([yes])
+AM_PROG_CC_C_O
 AC_PROG_CC_C99
 AC_USE_SYSTEM_EXTENSIONS
 AC_SEARCH_LIBS([getaddrinfo], [resolv nsl])

m4/pkg.m4

@@ -0,0 +1,275 @@
+dnl pkg.m4 - Macros to locate and utilise pkg-config.   -*- Autoconf -*-
+dnl serial 11 (pkg-config-0.29)
+dnl
+dnl Copyright © 2004 Scott James Remnant <scott@netsplit.com>.
+dnl Copyright © 2012-2015 Dan Nicholson <dbn.lists@gmail.com>
+dnl
+dnl This program is free software; you can redistribute it and/or modify
+dnl it under the terms of the GNU General Public License as published by
+dnl the Free Software Foundation; either version 2 of the License, or
+dnl (at your option) any later version.
+dnl
+dnl This program is distributed in the hope that it will be useful, but
+dnl WITHOUT ANY WARRANTY; without even the implied warranty of
+dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+dnl General Public License for more details.
+dnl
+dnl You should have received a copy of the GNU General Public License
+dnl along with this program; if not, write to the Free Software
+dnl Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+dnl 02111-1307, USA.
+dnl
+dnl As a special exception to the GNU General Public License, if you
+dnl distribute this file as part of a program that contains a
+dnl configuration script generated by Autoconf, you may include it under
+dnl the same distribution terms that you use for the rest of that
+dnl program.
+
+dnl PKG_PREREQ(MIN-VERSION)
+dnl -----------------------
+dnl Since: 0.29
+dnl
+dnl Verify that the version of the pkg-config macros are at least
+dnl MIN-VERSION. Unlike PKG_PROG_PKG_CONFIG, which checks the user's
+dnl installed version of pkg-config, this checks the developer's version
+dnl of pkg.m4 when generating configure.
+dnl
+dnl To ensure that this macro is defined, also add:
+dnl m4_ifndef([PKG_PREREQ],
+dnl     [m4_fatal([must install pkg-config 0.29 or later before running autoconf/autogen])])
+dnl
+dnl See the "Since" comment for each macro you use to see what version
+dnl of the macros you require.
+m4_defun([PKG_PREREQ],
+[m4_define([PKG_MACROS_VERSION], [0.29])
+m4_if(m4_version_compare(PKG_MACROS_VERSION, [$1]), -1,
+    [m4_fatal([pkg.m4 version $1 or higher is required but ]PKG_MACROS_VERSION[ found])])
+])dnl PKG_PREREQ
+
+dnl PKG_PROG_PKG_CONFIG([MIN-VERSION])
+dnl ----------------------------------
+dnl Since: 0.16
+dnl
+dnl Search for the pkg-config tool and set the PKG_CONFIG variable to
+dnl first found in the path. Checks that the version of pkg-config found
+dnl is at least MIN-VERSION. If MIN-VERSION is not specified, 0.9.0 is
+dnl used since that's the first version where most current features of
+dnl pkg-config existed.
+AC_DEFUN([PKG_PROG_PKG_CONFIG],
+[m4_pattern_forbid([^_?PKG_[A-Z_]+$])
+m4_pattern_allow([^PKG_CONFIG(_(PATH|LIBDIR|SYSROOT_DIR|ALLOW_SYSTEM_(CFLAGS|LIBS)))?$])
+m4_pattern_allow([^PKG_CONFIG_(DISABLE_UNINSTALLED|TOP_BUILD_DIR|DEBUG_SPEW)$])
+AC_ARG_VAR([PKG_CONFIG], [path to pkg-config utility])
+AC_ARG_VAR([PKG_CONFIG_PATH], [directories to add to pkg-config's search path])
+AC_ARG_VAR([PKG_CONFIG_LIBDIR], [path overriding pkg-config's built-in search path])
+
+if test "x$ac_cv_env_PKG_CONFIG_set" != "xset"; then
+	AC_PATH_TOOL([PKG_CONFIG], [pkg-config])
+fi
+if test -n "$PKG_CONFIG"; then
+	_pkg_min_version=m4_default([$1], [0.9.0])
+	AC_MSG_CHECKING([pkg-config is at least version $_pkg_min_version])
+	if $PKG_CONFIG --atleast-pkgconfig-version $_pkg_min_version; then
+		AC_MSG_RESULT([yes])
+	else
+		AC_MSG_RESULT([no])
+		PKG_CONFIG=""
+	fi
+fi[]dnl
+])dnl PKG_PROG_PKG_CONFIG
+
+dnl PKG_CHECK_EXISTS(MODULES, [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
+dnl -------------------------------------------------------------------
+dnl Since: 0.18
+dnl
+dnl Check to see whether a particular set of modules exists. Similar to
+dnl PKG_CHECK_MODULES(), but does not set variables or print errors.
+dnl
+dnl Please remember that m4 expands AC_REQUIRE([PKG_PROG_PKG_CONFIG])
+dnl only at the first occurence in configure.ac, so if the first place
+dnl it's called might be skipped (such as if it is within an "if", you
+dnl have to call PKG_CHECK_EXISTS manually
+AC_DEFUN([PKG_CHECK_EXISTS],
+[AC_REQUIRE([PKG_PROG_PKG_CONFIG])dnl
+if test -n "$PKG_CONFIG" && \
+    AC_RUN_LOG([$PKG_CONFIG --exists --print-errors "$1"]); then
+  m4_default([$2], [:])
+m4_ifvaln([$3], [else
+  $3])dnl
+fi])
+
+dnl _PKG_CONFIG([VARIABLE], [COMMAND], [MODULES])
+dnl ---------------------------------------------
+dnl Internal wrapper calling pkg-config via PKG_CONFIG and setting
+dnl pkg_failed based on the result.
+m4_define([_PKG_CONFIG],
+[if test -n "$$1"; then
+    pkg_cv_[]$1="$$1"
+ elif test -n "$PKG_CONFIG"; then
+    PKG_CHECK_EXISTS([$3],
+                     [pkg_cv_[]$1=`$PKG_CONFIG --[]$2 "$3" 2>/dev/null`
+		      test "x$?" != "x0" && pkg_failed=yes ],
+		     [pkg_failed=yes])
+ else
+    pkg_failed=untried
+fi[]dnl
+])dnl _PKG_CONFIG
+
+dnl _PKG_SHORT_ERRORS_SUPPORTED
+dnl ---------------------------
+dnl Internal check to see if pkg-config supports short errors.
+AC_DEFUN([_PKG_SHORT_ERRORS_SUPPORTED],
+[AC_REQUIRE([PKG_PROG_PKG_CONFIG])
+if $PKG_CONFIG --atleast-pkgconfig-version 0.20; then
+        _pkg_short_errors_supported=yes
+else
+        _pkg_short_errors_supported=no
+fi[]dnl
+])dnl _PKG_SHORT_ERRORS_SUPPORTED
+
+
+dnl PKG_CHECK_MODULES(VARIABLE-PREFIX, MODULES, [ACTION-IF-FOUND],
+dnl   [ACTION-IF-NOT-FOUND])
+dnl --------------------------------------------------------------
+dnl Since: 0.4.0
+dnl
+dnl Note that if there is a possibility the first call to
+dnl PKG_CHECK_MODULES might not happen, you should be sure to include an
+dnl explicit call to PKG_PROG_PKG_CONFIG in your configure.ac
+AC_DEFUN([PKG_CHECK_MODULES],
+[AC_REQUIRE([PKG_PROG_PKG_CONFIG])dnl
+AC_ARG_VAR([$1][_CFLAGS], [C compiler flags for $1, overriding pkg-config])dnl
+AC_ARG_VAR([$1][_LIBS], [linker flags for $1, overriding pkg-config])dnl
+
+pkg_failed=no
+AC_MSG_CHECKING([for $1])
+
+_PKG_CONFIG([$1][_CFLAGS], [cflags], [$2])
+_PKG_CONFIG([$1][_LIBS], [libs], [$2])
+
+m4_define([_PKG_TEXT], [Alternatively, you may set the environment variables $1[]_CFLAGS
+and $1[]_LIBS to avoid the need to call pkg-config.
+See the pkg-config man page for more details.])
+
+if test $pkg_failed = yes; then
+   	AC_MSG_RESULT([no])
+        _PKG_SHORT_ERRORS_SUPPORTED
+        if test $_pkg_short_errors_supported = yes; then
+	        $1[]_PKG_ERRORS=`$PKG_CONFIG --short-errors --print-errors --cflags --libs "$2" 2>&1`
+        else 
+	        $1[]_PKG_ERRORS=`$PKG_CONFIG --print-errors --cflags --libs "$2" 2>&1`
+        fi
+	# Put the nasty error message in config.log where it belongs
+	echo "$$1[]_PKG_ERRORS" >&AS_MESSAGE_LOG_FD
+
+	m4_default([$4], [AC_MSG_ERROR(
+[Package requirements ($2) were not met:
+
+$$1_PKG_ERRORS
+
+Consider adjusting the PKG_CONFIG_PATH environment variable if you
+installed software in a non-standard prefix.
+
+_PKG_TEXT])[]dnl
+        ])
+elif test $pkg_failed = untried; then
+     	AC_MSG_RESULT([no])
+	m4_default([$4], [AC_MSG_FAILURE(
+[The pkg-config script could not be found or is too old.  Make sure it
+is in your PATH or set the PKG_CONFIG environment variable to the full
+path to pkg-config.
+
+_PKG_TEXT
+
+To get pkg-config, see <http://pkg-config.freedesktop.org/>.])[]dnl
+        ])
+else
+	$1[]_CFLAGS=$pkg_cv_[]$1[]_CFLAGS
+	$1[]_LIBS=$pkg_cv_[]$1[]_LIBS
+        AC_MSG_RESULT([yes])
+	$3
+fi[]dnl
+])dnl PKG_CHECK_MODULES
+
+
+dnl PKG_CHECK_MODULES_STATIC(VARIABLE-PREFIX, MODULES, [ACTION-IF-FOUND],
+dnl   [ACTION-IF-NOT-FOUND])
+dnl ---------------------------------------------------------------------
+dnl Since: 0.29
+dnl
+dnl Checks for existence of MODULES and gathers its build flags with
+dnl static libraries enabled. Sets VARIABLE-PREFIX_CFLAGS from --cflags
+dnl and VARIABLE-PREFIX_LIBS from --libs.
+dnl
+dnl Note that if there is a possibility the first call to
+dnl PKG_CHECK_MODULES_STATIC might not happen, you should be sure to
+dnl include an explicit call to PKG_PROG_PKG_CONFIG in your
+dnl configure.ac.
+AC_DEFUN([PKG_CHECK_MODULES_STATIC],
+[AC_REQUIRE([PKG_PROG_PKG_CONFIG])dnl
+_save_PKG_CONFIG=$PKG_CONFIG
+PKG_CONFIG="$PKG_CONFIG --static"
+PKG_CHECK_MODULES($@)
+PKG_CONFIG=$_save_PKG_CONFIG[]dnl
+])dnl PKG_CHECK_MODULES_STATIC
+
+
+dnl PKG_INSTALLDIR([DIRECTORY])
+dnl -------------------------
+dnl Since: 0.27
+dnl
+dnl Substitutes the variable pkgconfigdir as the location where a module
+dnl should install pkg-config .pc files. By default the directory is
+dnl $libdir/pkgconfig, but the default can be changed by passing
+dnl DIRECTORY. The user can override through the --with-pkgconfigdir
+dnl parameter.
+AC_DEFUN([PKG_INSTALLDIR],
+[m4_pushdef([pkg_default], [m4_default([$1], ['${libdir}/pkgconfig'])])
+m4_pushdef([pkg_description],
+    [pkg-config installation directory @<:@]pkg_default[@:>@])
+AC_ARG_WITH([pkgconfigdir],
+    [AS_HELP_STRING([--with-pkgconfigdir], pkg_description)],,
+    [with_pkgconfigdir=]pkg_default)
+AC_SUBST([pkgconfigdir], [$with_pkgconfigdir])
+m4_popdef([pkg_default])
+m4_popdef([pkg_description])
+])dnl PKG_INSTALLDIR
+
+
+dnl PKG_NOARCH_INSTALLDIR([DIRECTORY])
+dnl --------------------------------
+dnl Since: 0.27
+dnl
+dnl Substitutes the variable noarch_pkgconfigdir as the location where a
+dnl module should install arch-independent pkg-config .pc files. By
+dnl default the directory is $datadir/pkgconfig, but the default can be
+dnl changed by passing DIRECTORY. The user can override through the
+dnl --with-noarch-pkgconfigdir parameter.
+AC_DEFUN([PKG_NOARCH_INSTALLDIR],
+[m4_pushdef([pkg_default], [m4_default([$1], ['${datadir}/pkgconfig'])])
+m4_pushdef([pkg_description],
+    [pkg-config arch-independent installation directory @<:@]pkg_default[@:>@])
+AC_ARG_WITH([noarch-pkgconfigdir],
+    [AS_HELP_STRING([--with-noarch-pkgconfigdir], pkg_description)],,
+    [with_noarch_pkgconfigdir=]pkg_default)
+AC_SUBST([noarch_pkgconfigdir], [$with_noarch_pkgconfigdir])
+m4_popdef([pkg_default])
+m4_popdef([pkg_description])
+])dnl PKG_NOARCH_INSTALLDIR
+
+
+dnl PKG_CHECK_VAR(VARIABLE, MODULE, CONFIG-VARIABLE,
+dnl [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
+dnl -------------------------------------------
+dnl Since: 0.28
+dnl
+dnl Retrieves the value of the pkg-config variable for the given module.
+AC_DEFUN([PKG_CHECK_VAR],
+[AC_REQUIRE([PKG_PROG_PKG_CONFIG])dnl
+AC_ARG_VAR([$1], [value of $3 for $2, overriding pkg-config])dnl
+
+_PKG_CONFIG([$1], [variable="][$3]["], [$2])
+AS_VAR_COPY([$1], [pkg_cv_][$1])
+
+AS_VAR_IF([$1], [""], [$5], [$4])dnl
+])dnl PKG_CHECK_VAR

src/common.c

@@ -0,0 +1,40 @@
+#include "common.h"
+
+#include <stdio.h>
+#include <stdarg.h>
+
+int gt_print (const char *fmt, ...)
+{
+    va_list ap;
+    va_start(ap, fmt);
+    int ret = vfprintf(stdout, fmt, ap);
+    va_end(ap);
+
+    if (ret<0)
+        return 0;
+
+    return ret;
+}
+
+void gt_log (const char *fmt, ...)
+{
+    va_list ap;
+    va_start(ap, fmt);
+    vfprintf(stderr, fmt, ap);
+    va_end(ap);
+}
+
+void gt_fatal (const char *fmt, ...)
+{
+    va_list ap;
+    va_start(ap, fmt);
+    vfprintf(stderr, fmt, ap);
+    va_end(ap);
+
+    exit(EXIT_FAILURE);
+}
+
+void gt_na (const char *name)
+{
+    gt_log("%s is not available on your platform!\n", name);
+}

src/common.h

@@ -14,7 +14,13 @@
 #define PALIGN(x)      ((void *)ALIGN((size_t)(x)))
 #define PALIGN_DOWN(x) ((void *)ALIGN_DOWN((size_t)(x)))
 
+#define _1_(x)         (__builtin_expect((x), 1))
+#define _0_(x)         (__builtin_expect((x), 0))
+
+#define _printf_(A,B)  __attribute__((format(printf,A,B)))
+#define _noreturn_     __attribute__((noreturn))
 #define _unused_       __attribute__((unused))
+#define _align_(...)   __attribute__((aligned(__VA_ARGS__)))
 
 typedef struct buffer buffer_t;
 
@@ -24,3 +30,8 @@ struct buffer {
     uint8_t *write;
     uint8_t *end;
 };
+
+int  gt_print (const char *, ...) _printf_(1,2);
+void gt_log   (const char *, ...) _printf_(1,2);
+void gt_fatal (const char *, ...) _printf_(1,2) _noreturn_;
+void gt_na    (const char *);

src/ip-static.h

@@ -0,0 +1,39 @@
+#pragma once
+
+#include <stdint.h>
+
+static inline int ip_get_version (const uint8_t *data, size_t size)
+{
+    if (size<20)   // XXX
+        return -1; // XXX
+
+    return data[0]>>4;
+}
+
+static inline void ip_set_size (uint8_t *data, size_t size)
+{
+    data[2] = 0xFF&(size>>8);
+    data[3] = 0xFF&(size);
+}
+
+static inline ssize_t ip_get_size (const uint8_t *data, size_t size)
+{
+    switch (ip_get_version(data, size)) {
+    case 4:
+        return (data[2]<<8)|data[3];
+    case -1:
+        return -1;
+    }
+
+    return 0;
+}
+
+static inline int ip_get_dscp (const uint8_t *data, size_t size)
+{
+    switch (ip_get_version(data, size)) {
+    case 4:
+        return data[1]>>2;
+    }
+
+    return 0;
+}

src/option.c

@@ -5,18 +5,10 @@
 
 #include "option.h"
 
-int option_flag (void *data, _unused_ int argc, _unused_ char **argv)
-{
-    const int one = 1;
-    byte_cpy(data, &one, sizeof(one));
-
-    return 0;
-}
-
 int option_str (void *data, int argc, char **argv)
 {
     if (argc<2 || !argv[1]) {
-        printf("option `%s' need a string argument\n", argv[0]);
+        gt_print("option `%s' need a string argument\n", argv[0]);
         return -1;
     }
 
@@ -28,7 +20,7 @@ int option_str (void *data, int argc, char **argv)
 int option_long (void *data, int argc, char **argv)
 {
     if (argc<2 || !argv[1]) {
-        printf("option `%s' need an integer argument\n", argv[0]);
+        gt_print("option `%s' need an integer argument\n", argv[0]);
         return -1;
     }
 
@@ -37,7 +29,7 @@ int option_long (void *data, int argc, char **argv)
     long val = strtol(argv[1], &end, 0);
 
     if (errno || argv[1]==end) {
-        printf("argument `%s' is not a valid integer\n", argv[1]);
+        gt_print("argument `%s' is not a valid integer\n", argv[1]);
         return -1;
     }
 
@@ -46,8 +38,21 @@ int option_long (void *data, int argc, char **argv)
     return 1;
 }
 
+int option_is_set (struct option *opts, const char *name)
+{
+    for (int k=0; opts[k].name; k++) {
+        if (!str_cmp(opts[k].name, name))
+            return opts[k].set;
+    }
+
+    return 0;
+}
+
 int option_option (void *data, int argc, char **argv)
 {
+    if (!data)
+        return 0;
+
     struct option *opts = (struct option *)data;
 
     for (int k=0; opts[k].name; k++)
@@ -61,7 +66,7 @@ int option_option (void *data, int argc, char **argv)
                 continue;
 
             if (opts[k].set) {
-                printf("option `%s' is already set\n", opts[k].name);
+                gt_print("option `%s' is already set\n", opts[k].name);
                 return -1;
             }
 
@@ -84,31 +89,31 @@ int option_option (void *data, int argc, char **argv)
     return argc;
 }
 
-static void option_usage (struct option *opts, char *name)
+static int option_usage (struct option *opts, int slen)
 {
-    char *usage = "usage: ";
+    if (!opts)
-    size_t slen = str_len(usage)+str_len(name);
+        return 0;
-    size_t len = slen;
 
-    printf("%s%s", usage, name);
+    int len = 0;
-
-    if (slen>40)
-        slen = 12;
 
     for (int k=0; opts[k].name; k++) {
-        char *arg = (opts[k].call==option_flag)?"":" ARG";
+        if (len>40) {
-        size_t inc = str_len(opts[k].name)+str_len(arg)+3;
+            gt_print("\n%*s", slen, "");
-
+            len = 0;
-        if (len+inc>72) {
-            printf("\n%*s", (int)slen, "");
-            len = slen;
         }
 
-        printf(" [%s%s]", opts[k].name, arg);
+        len += gt_print(" [%s", opts[k].name);
-        len += inc;
+
+        if (opts[k].call==option_option) {
+            len += option_usage((struct option *)opts[k].data, slen+len);
+        } else {
+            len += gt_print(" ARG");
+        }
+
+        len += gt_print("]");
     }
 
-    printf("\n");
+    return len;
 }
 
 int option (struct option *opts, int argc, char **argv)
@@ -121,8 +126,17 @@ int option (struct option *opts, int argc, char **argv)
     if (ret<0 || ret+1>=argc)
         return 1;
 
-    printf("option `%s' is unknown\n", argv[ret+1]);
+    gt_print("option `%s' is unknown\n", argv[ret+1]);
-    option_usage(opts, argv[0]);
+
+    int slen = gt_print("usage: %s", argv[0]);
+
+    if (slen>40) {
+        slen = 12;
+        gt_print("\n%*s", slen, "");
+    }
+
+    option_usage(opts, slen);
+    gt_print("\n");
 
     return 1;
 }

src/option.h

@@ -7,9 +7,9 @@ struct option {
     int set;
 };
 
-int option_flag   (void *, int, char **);
+int option_option (void *, int, char **);
 int option_str    (void *, int, char **);
 int option_long   (void *, int, char **);
-int option_option (void *, int, char **);
 
-int option (struct option *, int, char **);
+int option_is_set (struct option *, const char *);
+int option        (struct option *, int, char **);

src/tun.c

@@ -0,0 +1,209 @@
+#include "common-static.h"
+#include "ip-static.h"
+
+#include "tun.h"
+
+#include <stdio.h>
+#include <fcntl.h>
+
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <sys/uio.h>
+
+#ifdef __linux__
+# include <linux/if.h>
+# include <linux/if_tun.h>
+#endif
+
+#ifdef __APPLE__
+# include <sys/sys_domain.h>
+# include <sys/kern_control.h>
+# include <net/if_utun.h>
+#endif
+
+#if defined(__APPLE__) || defined(__OpenBSD__)
+# define GT_BSD_TUN 1
+#endif
+
+#ifdef __linux__
+int tun_create (char *name, int multiqueue)
+{
+    int fd = open("/dev/net/tun", O_RDWR);
+
+    if (fd<0) {
+        perror("open /dev/net/tun");
+        return -1;
+    }
+
+    struct ifreq ifr = {
+        .ifr_flags = IFF_TUN|IFF_NO_PI,
+    };
+
+    if (multiqueue) {
+#ifdef IFF_MULTI_QUEUE
+        ifr.ifr_flags |= IFF_MULTI_QUEUE;
+#else
+        gt_na("IFF_MULTI_QUEUE");
+#endif
+    }
+
+    str_cpy(ifr.ifr_name, name, IFNAMSIZ-1);
+
+    int ret = ioctl(fd, TUNSETIFF, &ifr);
+
+    if (ret<0) {
+        perror("ioctl TUNSETIFF");
+        return -1;
+    }
+
+    gt_log("tun name: %s\n", ifr.ifr_name);
+
+    return fd;
+}
+#elif defined(__APPLE__)
+int tun_create (_unused_ char *name, _unused_ int mq)
+{
+    for (unsigned dev_id = 0; dev_id < 32; dev_id++) {
+        struct ctl_info ci;
+
+        byte_set(&ci, 0, sizeof(ci));
+        str_cpy(ci.ctl_name, UTUN_CONTROL_NAME, sizeof(ci.ctl_name)-1);
+
+        int fd = socket(PF_SYSTEM, SOCK_DGRAM, SYSPROTO_CONTROL);
+
+        if (fd==-1)
+            return -1;
+
+        if (ioctl(fd, CTLIOCGINFO, &ci)==-1) {
+            close(fd);
+            continue;
+        }
+
+        struct sockaddr_ctl sc = {
+            .sc_id = ci.ctl_id,
+            .sc_len = sizeof(sc),
+            .sc_family = AF_SYSTEM,
+            .ss_sysaddr = AF_SYS_CONTROL,
+            .sc_unit = dev_id+1,
+        };
+
+        if (connect(fd, (struct sockaddr *)&sc, sizeof(sc))==-1) {
+            close(fd);
+            continue;
+        }
+
+        gt_log("tun name: /dev/utun%u\n", dev_id);
+
+        return fd;
+    }
+
+    return -1;
+}
+#else
+int tun_create (_unused_ char *name, _unused_ int mq)
+{
+    for (unsigned dev_id = 0; dev_id < 32; dev_id++) {
+        char dev_path[11];
+
+        snprintf(dev_path, sizeof(dev_path), "/dev/tun%u", dev_id);
+
+        int fd = open(dev_path, O_RDWR);
+
+        if (fd==-1)
+            continue;
+
+        gt_log("tun name: %s\n", dev_path);
+
+        return fd;
+    }
+
+    return -1;
+}
+#endif
+
+ssize_t tun_read (int fd, void *data, size_t size)
+{
+    if (!size)
+        return -1;
+
+#ifdef GT_BSD_TUN
+    uint32_t family;
+
+    struct iovec iov[2] = {
+        { .iov_base = &family, .iov_len = sizeof(family) },
+        { .iov_base = data, .iov_len = size }
+    };
+
+    ssize_t ret = readv(fd, iov, 2);
+#else
+    ssize_t ret = read(fd, data, size);
+#endif
+
+    if (ret==-1) {
+        if (errno==EAGAIN || errno==EINTR)
+            return -1;
+
+        if (errno)
+            perror("tun read");
+
+        return 0;
+    }
+
+#ifdef GT_BSD_TUN
+    if (ret<(ssize_t) sizeof(family))
+        return 0;
+
+    return ret-sizeof(family);
+#else
+    return ret;
+#endif
+}
+
+ssize_t tun_write (int fd, const void *data, size_t size)
+{
+    if (!size)
+        return -1;
+
+#ifdef GT_BSD_TUN
+    uint32_t family;
+
+    switch (ip_get_version(data, size)) {
+    case 4:
+        family = htonl(AF_INET);
+        break;
+    case 6:
+        family = htonl(AF_INET6);
+        break;
+    default:
+        return -1;
+    }
+
+    struct iovec iov[2] = {
+        { .iov_base = &family, .iov_len = sizeof(family) },
+        { .iov_base = (void *) data, .iov_len = size },
+    };
+
+    ssize_t ret = writev(fd, iov, 2);
+#else
+    ssize_t ret = write(fd, data, size);
+#endif
+
+    if (ret==-1) {
+        if (errno==EAGAIN || errno==EINTR)
+            return -1;
+
+        if (errno)
+            perror("tun write");
+
+        return 0;
+    }
+
+#ifdef GT_BSD_TUN
+    if (ret<(ssize_t) sizeof(family))
+        return 0;
+
+    return ret-sizeof(family);
+#else
+    return ret;
+#endif
+}

src/tun.h

@@ -0,0 +1,7 @@
+#pragma once
+
+#include <unistd.h>
+
+int     tun_create (char *, int);
+ssize_t tun_read   (int, void *, size_t);
+ssize_t tun_write  (int, const void *, size_t);

version.sh

@@ -0,0 +1,9 @@
+#!/bin/sh
+
+[ -z "${VERSION}" ] && VERSION=`git describe --tags --always 2>/dev/null` \
+                    && VERSION=${VERSION#v}
+
+[ -z "${VERSION}" ] && VERSION=`basename \`pwd\`` \
+                    && VERSION=${VERSION#*-}
+
+echo -n ${VERSION}