diff options
Diffstat (limited to 'lib/kernel/doc')
| -rw-r--r-- | lib/kernel/doc/src/inet.xml | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/lib/kernel/doc/src/inet.xml b/lib/kernel/doc/src/inet.xml index 4a3796a15b..e1b0b34888 100644 --- a/lib/kernel/doc/src/inet.xml +++ b/lib/kernel/doc/src/inet.xml @@ -722,6 +722,59 @@ fe80::204:acff:fe17:bf38 <p>Received <c>Packet</c> is delivered as defined by Mode.</p> </item> + <tag><c>{netns, Namespace :: file:filename_all()}</c></tag> + <item> + <p>Set a network namespace for the socket. The <c>Namespace</c> + parameter is a filename defining the namespace for example + <c>"/var/run/netns/example"</c> typically created by the command + <c>ip netns add example</c>. This option must be used in a + function call that creates a socket i.e + <seealso marker="gen_tcp#connect/3"> + gen_tcp:connect/3,4</seealso>, + <seealso marker="gen_tcp#listen/2"> + gen_tcp:listen/2</seealso>, + <seealso marker="gen_udp#open/1"> + gen_udp:open/1,2</seealso> or + <seealso marker="gen_sctp#open/0"> + gen_sctp:open/0-2</seealso>. + </p> + <p>This option uses the Linux specific syscall + <c>setns()</c> such as in Linux kernel 3.0 or later + and therefore only exists when the runtime system + has been compiled for such an operating system. + </p> + <p> + The virtual machine also needs elevated privileges either + running as superuser or (for Linux) having the capability + <c>CAP_SYS_ADMIN</c> according to the documentation for setns(2). + However, during testing also <c>CAP_SYS_PTRACE</c> + and <c>CAP_DAC_READ_SEARCH</c> has proven to be necessary. + Example:<code> +setcap cap_sys_admin,cap_sys_ptrace,cap_dac_read_search+epi beam.smp +</code> + Note also that the filesystem containing the virtual machine + executable (<c>beam.smp</c> in the example above) has to be local, + mounted without the <c>nosetuid</c> flag, + support extended attributes and that + the kernel has to support file capabilities. + All this runs out of the box on at least Ubuntu 12.04 LTS, + except that SCTP sockets appears to not support + network namespaces. + </p> + <p>The <c>Namespace</c> is a file name and is encoded + and decoded as discussed in + <seealso marker="file">file</seealso> + except that the emulator flag <c>+fnu</c> is ignored and + <seealso marker="#getopts/2">getopts/2</seealso> + for this option will return a binary for the filename + if the stored filename can not be decoded, + which should only happen if you set the option using a binary + that can not be decoded with the emulator's filename encoding: + <seealso marker="file#native_name_encoding/0"> + file:native_name_encoding/0</seealso>. + </p> + </item> + <tag><c>list</c></tag> <item> <p>Received <c>Packet</c> is delivered as a list.</p> |