Add .build.sh

Chacha20 will be automatically used if aesni is not available.

.gitmodules

@@ -1,3 +0,0 @@
-[submodule "mud"]
-	path = mud
-	url = https://github.com/angt/mud.git

Makefile.am

@@ -7,6 +7,7 @@ glorytun_LDADD = $(libsodium_LIBS)
 glorytun_SOURCES = \
     src/common.h \
     src/common.c \
+    src/buffer.h \
     src/ip.h \
     src/str.h \
     src/main.c \
@@ -15,12 +16,9 @@ glorytun_SOURCES = \
     src/tun.c \
     src/tun.h \
     src/db.c \
-    src/db.h
+    src/db.h \
-
+    src/state.c \
-glorytun_CFLAGS  += -I$(srcdir)/mud
+    src/state.h
-glorytun_SOURCES += \
-    mud/mud.h \
-    mud/mud.c
 
 EXTRA_DIST = \
     LICENSE \

README.md

@@ -1,6 +1,10 @@
-# π₁(Glorytun)=0
+# π₁(Glorytun)=ℤ²
 
-Small, Simple and Stupid VPN over [mud](https://github.com/angt/mud).
+Small, Simple and Stupid TCP VPN.
+
+#### Work In Progress
+
+This code will probably format your harddisk!
 
 #### Build and Install
 
@@ -8,7 +12,7 @@ Glorytun depends on [libsodium](https://github.com/jedisct1/libsodium) version >
 
 To build and install the latest version:
 
-    $ git clone https://github.com/angt/glorytun --recursive --branch mud
+    $ git clone https://github.com/angt/glorytun
     $ cd glorytun
     $ ./autogen.sh
     $ ./configure

configure.ac

@@ -14,6 +14,7 @@ AM_SILENT_RULES([yes])
 AM_PROG_CC_C_O
 AC_PROG_CC_C99
 AC_USE_SYSTEM_EXTENSIONS
+AC_SEARCH_LIBS([getaddrinfo], [resolv nsl])
 AC_SEARCH_LIBS([socket], [socket])
 AC_CHECK_LIB([rt], [clock_gettime])
 AC_CHECK_FUNCS([clock_gettime])

src/buffer.h

@@ -0,0 +1,66 @@
+#pragma once
+
+#include "common.h"
+
+typedef struct buffer buffer_t;
+
+struct buffer {
+    uint8_t *data;
+    uint8_t *read;
+    uint8_t *write;
+    uint8_t *end;
+};
+
+static inline void buffer_setup (buffer_t *buffer, void *data, size_t size)
+{
+    if (!data)
+        data = malloc(ALIGN(size));
+
+    buffer->data  = data;
+    buffer->read  = data;
+    buffer->write = data;
+    buffer->end   = data;
+    buffer->end  += size;
+}
+
+static inline void buffer_format (buffer_t *buffer)
+{
+    buffer->write = buffer->data;
+    buffer->read  = buffer->data;
+}
+
+_pure_
+static inline size_t buffer_size (buffer_t *buffer)
+{
+    return buffer->end-buffer->data;
+}
+
+_pure_
+static inline size_t buffer_write_size (buffer_t *buffer)
+{
+    return buffer->end-buffer->write;
+}
+
+_pure_
+static inline size_t buffer_read_size (buffer_t *buffer)
+{
+    return buffer->write-buffer->read;
+}
+
+static inline void buffer_shift (buffer_t *buffer)
+{
+    if (buffer->read==buffer->data)
+        return;
+
+    if (buffer->read==buffer->write) {
+        buffer_format(buffer);
+        return;
+    }
+
+    const size_t size = buffer_read_size(buffer);
+
+    memmove(buffer->data, buffer->read, size);
+
+    buffer->read  = buffer->data;
+    buffer->write = buffer->data+size;
+}

src/common.c

@@ -1,10 +1,9 @@
 #include "common.h"
 
-#include <stdarg.h>
 #include <stdio.h>
+#include <stdarg.h>
 
-int
+int gt_print (const char *fmt, ...)
-gt_print(const char *fmt, ...)
 {
     va_list ap;
     va_start(ap, fmt);
@@ -17,8 +16,7 @@ gt_print(const char *fmt, ...)
     return ret;
 }
 
-void
+void gt_log (const char *fmt, ...)
-gt_log(const char *fmt, ...)
 {
     va_list ap;
     va_start(ap, fmt);
@@ -26,8 +24,7 @@ gt_log(const char *fmt, ...)
     va_end(ap);
 }
 
-void
+void gt_fatal (const char *fmt, ...)
-gt_fatal(const char *fmt, ...)
 {
     va_list ap;
     va_start(ap, fmt);
@@ -37,19 +34,17 @@ gt_fatal(const char *fmt, ...)
     exit(EXIT_FAILURE);
 }
 
-void
+void gt_na (const char *name)
-gt_na(const char *name)
 {
     gt_log("%s is not available on your platform\n", name);
 }
 
-int
+int gt_tohex (char *dst, size_t dst_size, const uint8_t *src, size_t src_size)
-gt_tohex(char *dst, size_t dst_size, const uint8_t *src, size_t src_size)
 {
-    if (_0_(!dst_size))
+    if _0_(!dst_size)
         return -1;
 
-    if (_0_(((dst_size - 1) / 2) < src_size))
+    if _0_(((dst_size-1)/2)<src_size)
         return -1;
 
     static const char tbl[] = "0123456789ABCDEF";
@@ -64,8 +59,8 @@ gt_tohex(char *dst, size_t dst_size, const uint8_t *src, size_t src_size)
     return 0;
 }
 
-_const_ static inline int
+_const_
-fromhex(const char c)
+static inline int fromhex (const char c)
 {
     if (c>='0' && c<='9')
         return c-'0';
@@ -79,20 +74,19 @@ fromhex(const char c)
     return -1;
 }
 
-int
+int gt_fromhex (uint8_t *dst, size_t dst_size, const char *src, size_t src_size)
-gt_fromhex(uint8_t *dst, size_t dst_size, const char *src, size_t src_size)
 {
-    if (_0_(src_size & 1))
+    if _0_(src_size&1)
         return -1;
 
-    if (_0_(dst_size < (src_size / 2)))
+    if _0_(dst_size<(src_size/2))
         return -1;
 
     for (size_t i=0; i<src_size; i+=2) {
         const int a = fromhex(src[i]);
         const int b = fromhex(src[i+1]);
 
-        if (_0_(a == -1 || b == -1))
+        if _0_(a==-1 || b==-1)
             return -1;
 
         *dst++ = (a<<4)|b;

src/common.h

@@ -29,12 +29,6 @@
 #define _const_        __attribute__ ((const))
 #define _align_(...)   __attribute__ ((aligned(__VA_ARGS__)))
 
-#undef MAX
-#define MAX(x,y) ({ __typeof__(x) X=(x); __typeof__(y) Y=(y); X > Y ? X : Y; })
-
-#undef MIN
-#define MIN(x,y) ({ __typeof__(x) X=(x); __typeof__(y) Y=(y); X < Y ? X : Y; })
-
 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_;

src/db.c

@@ -12,14 +12,14 @@ struct node {
     uint32_t point;
 };
 
-_pure_ static inline size_t
+_pure_
-db_size(const uint8_t *a)
+static inline size_t db_size (const uint8_t *a)
 {
     return (a[0]?:str_len((char *)a+1))+1;
 }
 
-_pure_ static inline size_t
+_pure_
-db_cmp(const uint8_t *a, const uint8_t *b)
+static inline size_t db_cmp (const uint8_t *a, const uint8_t *b)
 {
     const size_t size = a[0];
 
@@ -39,8 +39,8 @@ db_cmp(const uint8_t *a, const uint8_t *b)
     return 0;
 }
 
-_pure_ static inline int
+_pure_
-db_dir(const uint32_t point, uint8_t *data, const size_t size)
+static inline int db_dir (const uint32_t point, uint8_t *data, const size_t size)
 {
     const size_t pos = point>>8;
 
@@ -50,10 +50,9 @@ db_dir(const uint32_t point, uint8_t *data, const size_t size)
     return ((point|data[pos])&255)==255;
 }
 
-uint8_t *
+uint8_t *db_search (uint8_t **p, uint8_t *data)
-db_search(uint8_t **p, uint8_t *data)
 {
-    if (_0_(!*p))
+    if _0_(!*p)
         return NULL;
 
     uint8_t *r = *p;
@@ -70,13 +69,12 @@ db_search(uint8_t **p, uint8_t *data)
     return NULL;
 }
 
-uint8_t *
+uint8_t *db_insert (uint8_t **p, uint8_t *data)
-db_insert(uint8_t **p, uint8_t *data)
 {
-    if (_0_(CBIT(data)))
+    if _0_(CBIT(data))
         return NULL;
 
-    if (_0_(!*p)) {
+    if _0_(!*p) {
         *p = data;
         return data;
     }
@@ -91,7 +89,7 @@ db_insert(uint8_t **p, uint8_t *data)
 
     const size_t diff = db_cmp(r, data);
 
-    if (_0_(!diff))
+    if _0_(!diff)
         return r;
 
     const size_t pos = diff-1;
@@ -109,7 +107,7 @@ db_insert(uint8_t **p, uint8_t *data)
 
     struct node *node = malloc(sizeof(struct node));
 
-    if (_0_(!node))
+    if _0_(!node)
         return NULL;
 
     const int dir = (mask|r[pos])==255;
@@ -123,10 +121,9 @@ db_insert(uint8_t **p, uint8_t *data)
     return data;
 }
 
-uint8_t *
+uint8_t *db_remove (uint8_t **p, uint8_t *data)
-db_remove(uint8_t **p, uint8_t *data)
 {
-    if (_0_(!*p))
+    if _0_(!*p)
         return NULL;
 
     const size_t size = db_size(data);
@@ -142,7 +139,7 @@ db_remove(uint8_t **p, uint8_t *data)
         p = node->child+dir;
     }
 
-    if (_0_(db_cmp(data, *p)))
+    if _0_(db_cmp(data, *p))
         return NULL;
 
     uint8_t *r = *p;

src/ip.h

@@ -4,14 +4,13 @@
 
 struct ip_common {
     uint8_t version;
-    uint8_t tc;
     uint8_t proto;
     uint8_t hdr_size;
     uint16_t size;
 };
 
-_pure_ static inline uint8_t
+_pure_
-ip_get_version(const uint8_t *data, size_t size)
+static inline uint8_t ip_get_version (const uint8_t *data, size_t size)
 {
     if (size<20)
         return 0;
@@ -19,20 +18,17 @@ ip_get_version(const uint8_t *data, size_t size)
     return data[0]>>4;
 }
 
-static inline int
+static inline int ip_get_common (struct ip_common *ic, const uint8_t *data, size_t size)
-ip_get_common(struct ip_common *ic, const uint8_t *data, size_t size)
 {
     ic->version = ip_get_version(data, size);
 
     switch (ic->version) {
     case 4:
-        ic->tc = data[1];
         ic->proto = data[9];
         ic->hdr_size = (data[0]&0xF)<<2;
         ic->size = ((data[2]<<8)|data[3]);
         return 0;
     case 6:
-        ic->tc = ((data[0] & 0xF) << 4) | (data[1] >> 4);
         ic->proto = data[6];
         ic->hdr_size = 40;
         ic->size = ((data[4]<<8)|data[5])+40;

src/option.c

@@ -3,8 +3,7 @@
 #include "option.h"
 #include "str.h"
 
-int
+int option_str (void *data, int argc, char **argv)
-option_str(void *data, int argc, char **argv)
 {
     if (argc<2 || str_empty(argv[1])) {
         gt_print("option `%s' need a string argument\n", argv[0]);
@@ -16,8 +15,7 @@ option_str(void *data, int argc, char **argv)
     return 1;
 }
 
-int
+int option_long (void *data, int argc, char **argv)
-option_long(void *data, int argc, char **argv)
 {
     if (argc<2 || str_empty(argv[1])) {
         gt_print("option `%s' need an integer argument\n", argv[0]);
@@ -38,8 +36,7 @@ option_long(void *data, int argc, char **argv)
     return 1;
 }
 
-int
+int option_is_set (struct option *opts, const char *name)
-option_is_set(struct option *opts, const char *name)
 {
     for (int k=0; opts[k].name; k++) {
         if (!str_cmp(opts[k].name, name))
@@ -49,8 +46,7 @@ option_is_set(struct option *opts, const char *name)
     return 0;
 }
 
-int
+int option_option (void *data, int argc, char **argv)
-option_option(void *data, int argc, char **argv)
 {
     if (!data)
         return 0;
@@ -91,8 +87,7 @@ option_option(void *data, int argc, char **argv)
     return argc;
 }
 
-static int
+static int option_usage (struct option *opts, int slen)
-option_usage(struct option *opts, int slen)
 {
     if (!opts)
         return 0;
@@ -119,8 +114,7 @@ option_usage(struct option *opts, int slen)
     return len;
 }
 
-int
+int option (struct option *opts, int argc, char **argv)
-option(struct option *opts, int argc, char **argv)
 {
     int ret = option_option(opts, argc, argv);
 

src/state.c

@@ -0,0 +1,62 @@
+#include "common.h"
+
+#include "state.h"
+#include "str.h"
+
+#include <stdio.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+
+int state_create (const char *filename)
+{
+    if (str_empty(filename))
+        return -1;
+
+    int fd = open(filename, O_WRONLY);
+
+    if (fd==-1) {
+        if (errno!=EINTR)
+            perror("open");
+        return -1;
+    }
+
+    struct stat st = {0};
+
+    if (fstat(fd, &st)==-1) {
+        perror("fstat");
+        close(fd);
+        return -1;
+    }
+
+    if (!S_ISFIFO(st.st_mode)) {
+        gt_log("`%s' is not a fifo\n", filename);
+        close(fd);
+        return -1;
+    }
+
+    return fd;
+}
+
+void state_send (int fd, const char *state, const char *info)
+{
+    if (str_empty(state))
+        return;
+
+    if (fd==-1) {
+        gt_print("%s %s\n", state, info);
+        return;
+    }
+
+    const char *strs[] = { state, " ", info, "\n" };
+    char *str = str_cat(strs, COUNT(strs));
+
+    if (!str) {
+        perror("str_cat");
+        return;
+    }
+
+    if (write(fd, str, str_len(str))==-1 && errno!=EINTR)
+        perror("write");
+
+    free(str);
+}

src/state.h

@@ -0,0 +1,4 @@
+#pragma once
+
+int  state_create (const char *);
+void state_send   (int, const char *, const char *);

src/str.h

@@ -2,8 +2,7 @@
 
 #include "common.h"
 
-static inline size_t
+static inline size_t str_cpy (char *restrict dst, const char *restrict src, size_t len)
-str_cpy(char *restrict dst, const char *restrict src, size_t len)
 {
     if (!dst || !src)
         return 0;
@@ -18,14 +17,14 @@ str_cpy(char *restrict dst, const char *restrict src, size_t len)
     return i;
 }
 
-_pure_ static inline int
+_pure_
-str_empty(const char *restrict str)
+static inline int str_empty (const char *restrict str)
 {
     return !str || !str[0];
 }
 
-_pure_ static inline size_t
+_pure_
-str_cmp(const char *restrict sa, const char *restrict sb)
+static inline size_t str_cmp (const char *restrict sa, const char *restrict sb)
 {
     if (!sa || !sb)
         return 1;
@@ -39,8 +38,8 @@ str_cmp(const char *restrict sa, const char *restrict sb)
     return i+1;
 }
 
-_pure_ static inline size_t
+_pure_
-str_len(const char *restrict str)
+static inline size_t str_len (const char *restrict str)
 {
     if (!str)
         return 0;
@@ -48,8 +47,7 @@ str_len(const char *restrict str)
     return strlen(str);
 }
 
-static inline char *
+static inline char *str_cat (const char **strs, size_t count)
-str_cat(const char **strs, size_t count)
 {
     size_t size = 1;
 

src/tun.c

@@ -1,28 +1,25 @@
 #include "common.h"
 
-#include "ip.h"
-#include "str.h"
 #include "tun.h"
+#include "str.h"
+#include "ip.h"
 
-#include <fcntl.h>
 #include <stdio.h>
+#include <fcntl.h>
 
 #include <sys/ioctl.h>
 #include <sys/socket.h>
 #include <sys/uio.h>
 
-#include <net/if.h>
-
 #ifdef __linux__
-#define IFF_TUN 0x0001
+#include <linux/if.h>
-#define IFF_NO_PI 0x1000
+#include <linux/if_tun.h>
-#define TUNSETIFF _IOW('T', 202, int)
 #endif
 
 #ifdef __APPLE__
-#include <net/if_utun.h>
-#include <sys/kern_control.h>
 #include <sys/sys_domain.h>
+#include <sys/kern_control.h>
+#include <net/if_utun.h>
 #endif
 
 #if defined(__APPLE__) || defined(__OpenBSD__)
@@ -31,8 +28,7 @@
 
 #ifdef __APPLE__
 
-static int
+static int tun_create_by_id (char *name, size_t size, unsigned id, _unused_ int mq)
-tun_create_by_id(char *name, size_t size, unsigned id)
 {
     int fd = socket(PF_SYSTEM, SOCK_DGRAM, SYSPROTO_CONTROL);
 
@@ -45,9 +41,7 @@ tun_create_by_id(char *name, size_t size, unsigned id)
     str_cpy(ci.ctl_name, UTUN_CONTROL_NAME, sizeof(ci.ctl_name)-1);
 
     if (ioctl(fd, CTLIOCGINFO, &ci)) {
-        int err = errno;
         close(fd);
-        errno = err;
         return -1;
     }
 
@@ -60,9 +54,7 @@ tun_create_by_id(char *name, size_t size, unsigned id)
     };
 
     if (connect(fd, (struct sockaddr *)&sc, sizeof(sc))) {
-        int err = errno;
         close(fd);
-        errno = err;
         return -1;
     }
 
@@ -71,25 +63,21 @@ tun_create_by_id(char *name, size_t size, unsigned id)
     return fd;
 }
 
-static int
+static int tun_create_by_name (char *name, size_t size, char *dev_name, int mq)
-tun_create_by_name(char *name, size_t size, char *dev_name)
 {
     unsigned id = 0;
 
-    if (sscanf(dev_name, "utun%u", &id) != 1) {
+    if (sscanf(dev_name, "utun%u", &id)!=1)
-        errno = EINVAL;
         return -1;
-    }
 
-    return tun_create_by_id(name, size, id);
+    return tun_create_by_id(name, size, id, mq);
 }
 
 #else /* not __APPLE__ */
 
 #ifdef __linux__
 
-static int
+static int tun_create_by_name (char *name, size_t size, char *dev_name, int mq)
-tun_create_by_name(char *name, size_t size, char *dev_name)
 {
     int fd = open("/dev/net/tun", O_RDWR);
 
@@ -100,6 +88,12 @@ tun_create_by_name(char *name, size_t size, char *dev_name)
         .ifr_flags = IFF_TUN|IFF_NO_PI,
     };
 
+    if (mq) {
+#ifdef IFF_MULTI_QUEUE
+        ifr.ifr_flags |= IFF_MULTI_QUEUE;
+#endif
+    }
+
     str_cpy(ifr.ifr_name, dev_name, IFNAMSIZ-1);
 
     if (ioctl(fd, TUNSETIFF, &ifr)) {
@@ -114,8 +108,7 @@ tun_create_by_name(char *name, size_t size, char *dev_name)
 
 #else /* not __linux__ not __APPLE__ */
 
-static int
+static int tun_create_by_name (char *name, size_t size, char *dev_name, _unused_ int mq)
-tun_create_by_name(char *name, size_t size, char *dev_name)
 {
     char path[64];
 
@@ -127,29 +120,32 @@ tun_create_by_name(char *name, size_t size, char *dev_name)
 
 #endif /* not __APPLE__ */
 
-static int
+static int tun_create_by_id (char *name, size_t size, unsigned id, int mq)
-tun_create_by_id(char *name, size_t size, unsigned id)
 {
     char dev_name[64];
 
     snprintf(dev_name, sizeof(dev_name), "tun%u", id);
 
-    return tun_create_by_name(name, size, dev_name);
+    return tun_create_by_name(name, size, dev_name, mq);
 }
 
 #endif
 
-int
+int tun_create (char *dev_name, char **ret_name, int mq)
-tun_create(char *dev_name, char **ret_name)
 {
     char name[64] = {0};
     int fd = -1;
 
+#ifndef IFF_MULTI_QUEUE
+    if (mq)
+        gt_na("IFF_MULTI_QUEUE");
+#endif
+
     if (str_empty(dev_name)) {
         for (unsigned id=0; id<32 && fd==-1; id++)
-            fd = tun_create_by_id(name, sizeof(name), id);
+            fd = tun_create_by_id(name, sizeof(name), id, mq);
     } else {
-        fd = tun_create_by_name(name, sizeof(name), dev_name);
+        fd = tun_create_by_name(name, sizeof(name), dev_name, mq);
     }
 
     if (fd!=-1 && ret_name)
@@ -158,45 +154,48 @@ tun_create(char *dev_name, char **ret_name)
     return fd;
 }
 
-int
+ssize_t tun_read (int fd, void *data, size_t size)
-tun_read(int fd, void *data, size_t size)
 {
     if (!size)
-        return 0;
+        return -1;
 
 #ifdef GT_BSD_TUN
     uint32_t family;
 
     struct iovec iov[2] = {
-        {
+        { .iov_base = &family, .iov_len = sizeof(family) },
-            .iov_base = &family,
+        { .iov_base = data, .iov_len = size }
-            .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 <= (ssize_t)0)
+    if (ret==-1) {
-        return ret;
+        if (errno==EAGAIN || errno==EINTR)
+            return -1;
 
-    if (ret <= (ssize_t)sizeof(family))
+        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 read(fd, data, size);
+    return ret;
 #endif
 }
 
-int
+ssize_t tun_write (int fd, const void *data, size_t size)
-tun_write(int fd, const void *data, size_t size)
 {
     if (!size)
-        return 0;
+        return -1;
 
 #ifdef GT_BSD_TUN
     uint32_t family;
@@ -209,54 +208,35 @@ tun_write(int fd, const void *data, size_t size)
         family = htonl(AF_INET6);
         break;
     default:
-        errno = EINVAL;
         return -1;
     }
 
     struct iovec iov[2] = {
-        {
+        { .iov_base = &family, .iov_len = sizeof(family) },
-            .iov_base = &family,
+        { .iov_base = (void *) data, .iov_len = size },
-            .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 <= (ssize_t)0)
+    if (ret==-1) {
-        return ret;
+        if (errno==EAGAIN || errno==EINTR)
+            return -1;
 
-    if (ret <= (ssize_t)sizeof(family))
+        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 write(fd, data, size);
+    return ret;
 #endif
 }
-
-int
-tun_set_mtu(char *dev_name, int mtu)
-{
-    struct ifreq ifr = {
-        .ifr_mtu = mtu,
-    };
-
-    str_cpy(ifr.ifr_name, dev_name, IFNAMSIZ - 1);
-
-    int fd = socket(AF_INET, SOCK_DGRAM, 0);
-
-    if (fd == -1)
-        return -1;
-
-    int ret = ioctl(fd, SIOCSIFMTU, &ifr);
-
-    int err = errno;
-    close(fd);
-    errno = err;
-
-    return ret;
-}

src/tun.h

@@ -1,6 +1,7 @@
 #pragma once
 
-int tun_create  (char *, char **);
+#include <unistd.h>
-int tun_read    (int, void *, size_t);
+
-int tun_write   (int, const void *, size_t);
+int     tun_create (char *, char **, int);
-int tun_set_mtu (char *, int);
+ssize_t tun_read   (int, void *, size_t);
+ssize_t tun_write  (int, const void *, size_t);