I want to create a tap interface to test networking and if I run sudo ip tuntap add tap3 mode tap
I get an error:
ubuntu@box316:/dev$ sudo ip tuntap add tap3 mode tap
open: No such file or directory
I then run it with strace
Isee that the ‘tun’ character device isn’t available:
ubuntu@box316:/dev$ sudo strace ip tuntap add tap3 mode tap
execve("/sbin/ip", ["ip", "tuntap", "add", "tap3", "mode", "tap"], [/* 14 vars */]) = 0
brk(0) = 0x1baf000
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f09c8768000
access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=74438, ...}) = 0
mmap(NULL, 74438, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f09c8755000
close(3) = 0
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libdl.so.2", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\320\16\0\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0644, st_size=14664, ...}) = 0
mmap(NULL, 2109744, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f09c8344000
mprotect(0x7f09c8347000, 2093056, PROT_NONE) = 0
mmap(0x7f09c8546000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x2000) = 0x7f09c8546000
close(3) = 0
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\320\37\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1840928, ...}) = 0
mmap(NULL, 3949248, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f09c7f7f000
mprotect(0x7f09c813a000, 2093056, PROT_NONE) = 0
mmap(0x7f09c8339000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1ba000) = 0x7f09c8339000
mmap(0x7f09c833f000, 17088, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f09c833f000
close(3) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f09c8754000
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f09c8752000
arch_prctl(ARCH_SET_FS, 0x7f09c8752740) = 0
mprotect(0x7f09c8339000, 16384, PROT_READ) = 0
mprotect(0x7f09c8546000, 4096, PROT_READ) = 0
mprotect(0x646000, 4096, PROT_READ) = 0
mprotect(0x7f09c876a000, 4096, PROT_READ) = 0
munmap(0x7f09c8755000, 74438) = 0
socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC, 0) = 3
setsockopt(3, SOL_SOCKET, SO_SNDBUF, [32768], 4) = 0
setsockopt(3, SOL_SOCKET, SO_RCVBUF, [1048576], 4) = 0
bind(3, {sa_family=AF_NETLINK, pid=0, groups=00000000}, 12) = 0
getsockname(3, {sa_family=AF_NETLINK, pid=22033, groups=00000000}, [12]) = 0
open("/dev/net/tun", O_RDWR) = -1 ENOENT (No such file or directory)
dup(2) = 4
fcntl(4, F_GETFL) = 0x8002 (flags O_RDWR|O_LARGEFILE)
brk(0) = 0x1baf000
brk(0x1bd0000) = 0x1bd0000
fstat(4, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 7), ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f09c8767000
lseek(4, 0, SEEK_CUR) = -1 ESPIPE (Illegal seek)
write(4, "open: No such file or directory\n", 32open: No such file or directory
) = 32
close(4) = 0
munmap(0x7f09c8767000, 4096) = 0
exit_group(1) = ?
+++ exited with 1 +++
We see the error is that /dev/net/tun
is cannot be opened:
open("/dev/net/tun", O_RDWR) = -1 ENOENT (No such file or directory)
And sure enough there is no /dev/net/tun
character device:
ubuntu@box175:~$ ls -al /dev/net
total 0
drwxr-xr-x 2 root root 40 Jun 9 20:22 .
drwxr-xr-x 6 root root 500 Jun 9 20:22 ..
Anyone have ideas on what I’m doing wrong or have other suggestions on a work around?