Update mud

Required on BSD. Doesn't break anything elsewhere.

src/common.c

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

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

@@ -1,19 +1,19 @@
 #include "common.h"
 
 #include "buffer.h"
-#include "ip.h"
-#include "str.h"
-#include "option.h"
-#include "tun.h"
 #include "db.h"
+#include "ip.h"
+#include "option.h"
 #include "state.h"
+#include "str.h"
+#include "tun.h"
 
+#include <fcntl.h>
 #include <inttypes.h>
 #include <limits.h>
-#include <stdio.h>
-#include <signal.h>
 #include <poll.h>
-#include <fcntl.h>
+#include <signal.h>
+#include <stdio.h>
 #include <sys/socket.h>
 #include <sys/time.h>
 
@@ -33,7 +33,8 @@ static struct {
     int state_fd;
 } gt;
 
-static void fd_set_nonblock (int fd)
+static void
+fd_set_nonblock(int fd)
 {
     int ret;
 
@@ -51,7 +52,8 @@ static void fd_set_nonblock (int fd)
         perror("fcntl O_NONBLOCK");
 }
 
-static void gt_sa_handler (int sig)
+static void
+gt_sa_handler(int sig)
 {
     switch (sig) {
     case SIGINT:
@@ -65,7 +67,8 @@ static void gt_sa_handler (int sig)
     }
 }
 
-static void gt_set_signal (void)
+static void
+gt_set_signal(void)
 {
     struct sigaction sa = {
         .sa_flags = 0,
@@ -84,7 +87,8 @@ static void gt_set_signal (void)
     sigaction(SIGPIPE, &sa, NULL);
 }
 
-static ssize_t fd_read (int fd, void *data, size_t size)
+static ssize_t
+fd_read(int fd, void *data, size_t size)
 {
     if ((fd == -1) || !size)
         return -1;
@@ -104,7 +108,8 @@ static ssize_t fd_read (int fd, void *data, size_t size)
     return ret;
 }
 
-static ssize_t fd_write (int fd, const void *data, size_t size)
+static ssize_t
+fd_write(int fd, const void *data, size_t size)
 {
     if ((fd == -1) || !size)
         return -1;
@@ -127,7 +132,8 @@ static ssize_t fd_write (int fd, const void *data, size_t size)
     return ret;
 }
 
-static size_t fd_read_all (int fd, void *data, size_t size)
+static size_t
+fd_read_all(int fd, void *data, size_t size)
 {
     size_t done = 0;
 
@@ -155,7 +161,8 @@ static size_t fd_read_all (int fd, void *data, size_t size)
     return done;
 }
 
-static size_t fd_write_all (int fd, const void *data, size_t size)
+static size_t
+fd_write_all(int fd, const void *data, size_t size)
 {
     size_t done = 0;
 
@@ -183,7 +190,8 @@ static size_t fd_write_all (int fd, const void *data, size_t size)
     return done;
 }
 
-static int gt_setup_secretkey (struct mud *mud, char *keyfile)
+static int
+gt_setup_secretkey(struct mud *mud, char *keyfile)
 {
     unsigned char key[32];
 
@@ -231,7 +239,8 @@ static int gt_setup_secretkey (struct mud *mud, char *keyfile)
     return 0;
 }
 
-int main (int argc, char **argv)
+int
+main(int argc, char **argv)
 {
     gt_set_signal();
 
@@ -239,6 +248,7 @@ int main (int argc, char **argv)
     long port = 5000;
 
     char *bind_list = NULL;
+    char *bind_backup = NULL;
     long bind_port = 5000;
 
     char *dev = NULL;
@@ -259,14 +269,15 @@ int main (int argc, char **argv)
 #endif
 
     struct option opts[] = {
+        // clang-format off
         { "host",           &host,           option_str    },
         { "port",           &port,           option_long   },
         { "bind",           &bind_list,      option_str    },
+        { "bind-backup",    &bind_backup,    option_str    },
         { "bind-port",      &bind_port,      option_long   },
         { "dev",            &dev,            option_str    },
         { "mtu",            &mtu,            option_long   },
         { "keyfile",        &keyfile,        option_str    },
-        { "multiqueue",     NULL,            option_option },
         { "statefile",      &statefile,      option_str    },
         { "timeout",        &gt.timeout,     option_long   },
         { "time-tolerance", &time_tolerance, option_long   },
@@ -275,6 +286,7 @@ int main (int argc, char **argv)
         { "chacha20",       NULL,            option_option },
         { "version",        NULL,            option_option },
         {  NULL                                            },
+        // clang-format on
     };
 
     if (option(opts, argc, argv))
@@ -311,6 +323,15 @@ int main (int argc, char **argv)
         return 1;
     }
 
+    int icmp_fd = -1;
+
+    if (v4) {
+        icmp_fd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
+
+        if (icmp_fd == -1)
+            gt_log("couldn't create ICMP socket\n");
+    }
+
     gt.state_fd = state_create(statefile);
 
     if (statefile && gt.state_fd == -1)
@@ -318,18 +339,23 @@ int main (int argc, char **argv)
 
     char *tun_name = NULL;
 
-    int tun_fd = tun_create(dev, &tun_name, option_is_set(opts, "multiqueue"));
+    int tun_fd = tun_create(dev, &tun_name);
 
     if (tun_fd == -1) {
         gt_log("couldn't create tun device\n");
         return 1;
     }
 
+    if (tun_set_mtu(tun_name, mtu) == -1) {
+        perror("tun_set_mtu");
+        return 1;
+    }
+
     fd_set_nonblock(tun_fd);
 
     int chacha = option_is_set(opts, "chacha20");
 
-    struct mud *mud = mud_create(bind_port, v4, v6, !chacha);
+    struct mud *mud = mud_create(bind_port, v4, v6, !chacha, mtu);
 
     if (!mud) {
         gt_log("couldn't create mud\n");
@@ -344,139 +370,150 @@ int main (int argc, char **argv)
     if (time_tolerance > 0)
         mud_set_time_tolerance_sec(mud, time_tolerance);
 
-    if (host && port && bind_list) {
+    if (host && port) {
+        if (bind_backup) {
+            if (mud_peer(mud, bind_backup, host, port, 1)) {
+                perror("mud_peer (backup)");
+                return 1;
+            }
+        }
+
+        if (bind_list) {
             char tmp[1024];
             char *name = &tmp[0];
 
-        size_t size = str_cpy(tmp, bind_list, sizeof(tmp)-1);
+            str_cpy(tmp, bind_list, sizeof(tmp) - 1);
 
-        for (size_t i=0; i<size; i++) {
-            if (tmp[i]!=',')
-                continue;
+            while (*name) {
+                char *p = name;
 
-            tmp[i] = 0;
+                while (*p && *p != ',')
+                    p++;
 
-            if (mud_peer(mud, name, host, port))
+                if (*p)
+                    *p++ = 0;
+
+                if (mud_peer(mud, name, host, port, 0)) {
+                    perror("mud_peer");
                     return 1;
-
-            name = &tmp[i+1];
                 }
 
-        if (name[0] && mud_peer(mud, name, host, port))
-            return 1;
+                name = p;
+            }
+        }
     }
 
     int mud_fd = mud_get_fd(mud);
 
+    fd_set_nonblock(mud_fd);
+
     state_send(gt.state_fd, "INITIALIZED", tun_name);
 
     fd_set rfds;
     FD_ZERO(&rfds);
 
-    int started = 0;
-
-    struct {
-        unsigned char *buf;
-    } send, recv;
-
-    send.buf = malloc(2*mtu);
-    recv.buf = malloc(mtu);
-
-    size_t send_size = 0;
-    size_t send_limit = 0;
-    int send_tc = 0;
-    int send_next_tc = 0;
+    unsigned char buf[8 * 1024];
 
     while (!gt.quit) {
         FD_SET(tun_fd, &rfds);
-
-        if (mud_can_pull(mud)) {
         FD_SET(mud_fd, &rfds);
-        } else {
-            FD_CLR(mud_fd, &rfds);
-        }
 
-        struct timeval timeout = {
-            .tv_usec = 100000,
-        };
+        if (icmp_fd != -1)
+            FD_SET(icmp_fd, &rfds);
 
-        if (mud_can_push(mud) || send_size)
-            timeout.tv_usec = 1000;
-
-        if _0_(select(mud_fd+1, &rfds, NULL, NULL, &timeout)==-1) {
+        if (select(mud_fd + 1, &rfds, NULL, NULL, NULL) == -1) {
             if (errno == EINTR)
                 continue;
             perror("select");
             return 1;
         }
 
-        if (mud_is_up(mud)) {
-            if (!started) {
-                state_send(gt.state_fd, "STARTED", tun_name);
-                started = 1;
+        if (icmp_fd != -1 && FD_ISSET(icmp_fd, &rfds)) {
+            struct sockaddr_storage ss;
+            socklen_t sl = sizeof(ss);
+            ssize_t r = recvfrom(icmp_fd, buf, sizeof(buf), 0,
+                                 (struct sockaddr *)&ss, &sl);
+            if (r >= 8) {
+                struct ip_common ic;
+                if (!ip_get_common(&ic, buf, r) && ic.proto == 1) {
+                    unsigned char *data = &buf[ic.hdr_size];
+                    if (data[0] == 3) {
+                        int new_mtu = (data[6] << 8) | data[7];
+                        if (new_mtu) {
+                            gt_log("received MTU from ICMP: %i\n", new_mtu);
+                            mud_set_mtu(mud, new_mtu - 50); // XXX
+                        }
+                    }
                 }
-        } else {
-            if (started) {
-                state_send(gt.state_fd, "STOPPED", tun_name);
-                started = 0;
             }
         }
 
         if (FD_ISSET(tun_fd, &rfds)) {
-            while (send_size<mtu) {
-                const ssize_t r = tun_read(tun_fd, send.buf+send_size, mtu);
+            size_t size = 0;
 
-                if (r<=0) {
-                    gt.quit |= !r;
+            while (sizeof(buf) - size > mtu) {
+                const ssize_t r = tun_read(tun_fd, &buf[size],
+                                           sizeof(buf) - size);
+                if (r <= 0)
                     break;
-                }
 
                 struct ip_common ic;
 
-                if (ip_get_common(&ic, send.buf+send_size, mtu) || ic.size!=r) {
-                    gt_log("packet dropped: malformed\n");
-                    continue;
+                if (ip_get_common(&ic, &buf[size], r) || ic.size != r)
+                    break;
+
+                size += r;
             }
 
-                send_size += r;
+            int p = 0;
 
-                int update_tc = (ic.tc&0xFC)>(send_tc&0xFC);
+            while (p < size) {
+                int tc = 0;
+                int q = p;
 
-                if (send_size<=mtu) {
-                    send_limit = send_size;
-                    if ((ic.tc&0xFC)>(send_tc&0xFC))
-                        send_tc = ic.tc;
+                while (q < size) {
+                    struct ip_common ic;
+
+                    if ((ip_get_common(&ic, &buf[q], size - q)) ||
+                        (ic.size > size - q)) {
+                        size = q;
+                        break;
+                    }
+
+                    if (q + ic.size > p + mtu)
+                        break;
+
+                    q += ic.size;
+
+                    if (tc < (ic.tc & 0xFC))
+                        tc = ic.tc & 0xFC;
+                }
+
+                int r = mud_send(mud, &buf[p], q - p, tc);
+
+                if (r == -1 && errno == EMSGSIZE) {
+                    int new_mtu = mud_get_mtu(mud);
+
+                    if (new_mtu != mtu) {
+                        mtu = new_mtu;
+
+                        gt_log("MTU changed: %li\n", mtu);
+
+                        if (tun_set_mtu(tun_name, mtu) == -1)
+                            perror("tun_set_mtu");
+                    }
                 } else {
-                    if ((ic.tc&0xFC)>(send_next_tc&0xFC))
-                        send_next_tc = ic.tc;
-                }
-            }
-        }
-
-        if (send_limit) {
-            int r = mud_send(mud, send.buf, send_limit, send_tc);
-            if (r==-1 && errno!=EAGAIN) {
+                    if (r == -1 && errno != EAGAIN)
                         perror("mud_send");
-            } else if (r==send_limit) {
-                if (send_size>send_limit)
-                    memmove(&send.buf[0], &send.buf[send_limit], send_size-send_limit);
-                send_size -= send_limit;
-                send_limit = send_size;
-                send_tc = send_next_tc;
-                send_next_tc = 0;
-            }
-        }
 
-        if (mud_push(mud)==-1 && errno!=EAGAIN)
-            perror("mud_push");
+                    p = q;
+                }
+            }
+        }
 
         if (FD_ISSET(mud_fd, &rfds)) {
-            if (mud_pull(mud)==-1 && errno!=EAGAIN)
-                perror("mud_pull");
-        }
-
-        while (!gt.quit) {
-            const int size = mud_recv(mud, recv.buf, mtu);
+            while (1) {
+                const int size = mud_recv(mud, buf, sizeof(buf));
 
                 if (size <= 0) {
                     if (size == -1 && errno != EAGAIN)
@@ -489,20 +526,17 @@ int main (int argc, char **argv)
                 while (p < size) {
                     struct ip_common ic;
 
-                if (ip_get_common(&ic, recv.buf+p, size-p) || ic.size>size-p)
+                    if ((ip_get_common(&ic, &buf[p], size - p)) ||
+                        (ic.size > size - p))
                         break;
 
-                const ssize_t r = tun_write(tun_fd, recv.buf+p, ic.size);
-
-                if (r<=0) {
-                    gt.quit |= !r;
-                    break;
-                }
+                    tun_write(tun_fd, &buf[p], ic.size);
 
                     p += ic.size;
                 }
             }
         }
+    }
 
     return 0;
 }

src/option.c

@@ -3,7 +3,8 @@
 #include "option.h"
 #include "str.h"
 
-int option_str (void *data, int argc, char **argv)
+int
+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]);
@@ -15,7 +16,8 @@ int option_str (void *data, int argc, char **argv)
     return 1;
 }
 
-int option_long (void *data, int argc, char **argv)
+int
+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]);
@@ -36,7 +38,8 @@ int option_long (void *data, int argc, char **argv)
     return 1;
 }
 
-int option_is_set (struct option *opts, const char *name)
+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))
@@ -46,7 +49,8 @@ int option_is_set (struct option *opts, const char *name)
     return 0;
 }
 
-int option_option (void *data, int argc, char **argv)
+int
+option_option(void *data, int argc, char **argv)
 {
     if (!data)
         return 0;
@@ -87,7 +91,8 @@ int option_option (void *data, int argc, char **argv)
     return argc;
 }
 
-static int option_usage (struct option *opts, int slen)
+static int
+option_usage(struct option *opts, int slen)
 {
     if (!opts)
         return 0;
@@ -114,7 +119,8 @@ static int option_usage (struct option *opts, int slen)
     return len;
 }
 
-int option (struct option *opts, int argc, char **argv)
+int
+option(struct option *opts, int argc, char **argv)
 {
     int ret = option_option(opts, argc, argv);
 

src/state.c

@@ -3,11 +3,12 @@
 #include "state.h"
 #include "str.h"
 
-#include <stdio.h>
 #include <fcntl.h>
+#include <stdio.h>
 #include <sys/stat.h>
 
-int state_create (const char *filename)
+int
+state_create(const char *filename)
 {
     if (str_empty(filename))
         return -1;
@@ -37,7 +38,8 @@ int state_create (const char *filename)
     return fd;
 }
 
-void state_send (int fd, const char *state, const char *info)
+void
+state_send(int fd, const char *state, const char *info)
 {
     if (str_empty(state))
         return;

src/tun.c

@@ -1,25 +1,26 @@
 #include "common.h"
 
-#include "tun.h"
-#include "str.h"
 #include "ip.h"
+#include "str.h"
+#include "tun.h"
 
-#include <stdio.h>
 #include <fcntl.h>
+#include <stdio.h>
 
 #include <sys/ioctl.h>
 #include <sys/socket.h>
 #include <sys/uio.h>
 
+#include <net/if.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>
+#include <sys/kern_control.h>
+#include <sys/sys_domain.h>
 #endif
 
 #if defined(__APPLE__) || defined(__OpenBSD__)
@@ -28,7 +29,8 @@
 
 #ifdef __APPLE__
 
-static int tun_create_by_id (char *name, size_t size, unsigned id, _unused_ int mq)
+static int
+tun_create_by_id(char *name, size_t size, unsigned id)
 {
     int fd = socket(PF_SYSTEM, SOCK_DGRAM, SYSPROTO_CONTROL);
 
@@ -63,21 +65,23 @@ static int tun_create_by_id (char *name, size_t size, unsigned id, _unused_ int
     return fd;
 }
 
-static int tun_create_by_name (char *name, size_t size, char *dev_name, int mq)
+static int
+tun_create_by_name(char *name, size_t size, char *dev_name)
 {
     unsigned id = 0;
 
     if (sscanf(dev_name, "utun%u", &id) != 1)
         return -1;
 
-    return tun_create_by_id(name, size, id, mq);
+    return tun_create_by_id(name, size, id);
 }
 
 #else /* not __APPLE__ */
 
 #ifdef __linux__
 
-static int tun_create_by_name (char *name, size_t size, char *dev_name, int mq)
+static int
+tun_create_by_name(char *name, size_t size, char *dev_name)
 {
     int fd = open("/dev/net/tun", O_RDWR);
 
@@ -88,12 +92,6 @@ static int tun_create_by_name (char *name, size_t size, char *dev_name, int mq)
         .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)) {
@@ -108,7 +106,8 @@ static int tun_create_by_name (char *name, size_t size, char *dev_name, int mq)
 
 #else /* not __linux__ not __APPLE__ */
 
-static int tun_create_by_name (char *name, size_t size, char *dev_name, _unused_ int mq)
+static int
+tun_create_by_name(char *name, size_t size, char *dev_name)
 {
     char path[64];
 
@@ -120,32 +119,29 @@ static int tun_create_by_name (char *name, size_t size, char *dev_name, _unused_
 
 #endif /* not __APPLE__ */
 
-static int tun_create_by_id (char *name, size_t size, unsigned id, int mq)
+static int
+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, mq);
+    return tun_create_by_name(name, size, dev_name);
 }
 
 #endif
 
-int tun_create (char *dev_name, char **ret_name, int mq)
+int
+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, mq);
+            fd = tun_create_by_id(name, sizeof(name), id);
     } else {
-        fd = tun_create_by_name(name, sizeof(name), dev_name, mq);
+        fd = tun_create_by_name(name, sizeof(name), dev_name);
     }
 
     if (fd != -1 && ret_name)
@@ -154,7 +150,8 @@ int tun_create (char *dev_name, char **ret_name, int mq)
     return fd;
 }
 
-ssize_t tun_read (int fd, void *data, size_t size)
+ssize_t
+tun_read(int fd, void *data, size_t size)
 {
     if (!size)
         return -1;
@@ -163,8 +160,14 @@ ssize_t tun_read (int fd, void *data, size_t size)
     uint32_t family;
 
     struct iovec iov[2] = {
-        { .iov_base = &family, .iov_len = sizeof(family) },
-        { .iov_base = data, .iov_len = size }
+        {
+            .iov_base = &family,
+            .iov_len = sizeof(family),
+        },
+        {
+            .iov_base = data,
+            .iov_len = size,
+        },
     };
 
     ssize_t ret = readv(fd, iov, 2);
@@ -192,7 +195,8 @@ ssize_t tun_read (int fd, void *data, size_t size)
 #endif
 }
 
-ssize_t tun_write (int fd, const void *data, size_t size)
+ssize_t
+tun_write(int fd, const void *data, size_t size)
 {
     if (!size)
         return -1;
@@ -212,8 +216,14 @@ ssize_t tun_write (int fd, const void *data, size_t size)
     }
 
     struct iovec iov[2] = {
-        { .iov_base = &family, .iov_len = sizeof(family) },
-        { .iov_base = (void *) data, .iov_len = size },
+        {
+            .iov_base = &family,
+            .iov_len = sizeof(family),
+        },
+        {
+            .iov_base = (void *)data,
+            .iov_len = size,
+        },
     };
 
     ssize_t ret = writev(fd, iov, 2);
@@ -240,3 +250,26 @@ ssize_t tun_write (int fd, const void *data, size_t 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

@@ -2,6 +2,7 @@
 
 #include <unistd.h>
 
-int     tun_create (char *, char **, int);
+int     tun_create  (char *, char **);
 ssize_t tun_read    (int, void *, size_t);
 ssize_t tun_write   (int, const void *, size_t);
+int     tun_set_mtu (char *, int);