NAME

       vde_addstack, vde_delstack, vde_stackcmd, vde_msocket - vde network namespace as a user library

SYNOPSIS

       #include *vdestack.h*

       struct vdestack *vde_addstack(char *vdenet, char *ifname);

       void vde_delstack(struct vdestack *stack);

       int vde_stackcmd(struct vdestack *stack, char *stackcmd);

       int vde_msocket(struct vdestack *stack,int domain, int type, int protocol);

       void vde_default_stack(struct vdestack *stack);

DESCRIPTION

       Libvdestack  implements  the  idea  of  Internet of Threads through network namespaces.  By libvdestack a
       program can use one (or even several) private  networking  protocol  stack(s),  thus  a  program  can  be
       assigned its own IP address(es), routing etc.

       vde_addstack
              create  a  private  network  namespace:  vdenet  is the URL-like specification of a vde network as
              described in :vde_plug(1).  ifname is the name of the interface in the  network  namespace.   When
              ifname is NULL, the default interface :name is vde0.

       vde_delstack
              destroy a vdestack when it is no longer needed.

       vde_stackcmd
              run  a  command  or  a comma separated sequence of commands in the private network namespace.  The
              purpose of this function is to configure the networking parameters and options  (e.g. IP  address,
              routing).  For security reasons, commands must be specified using full pathnames.  Do not use this
              function to start long lasting or non terminating programs, the caller waits for  the  termination
              of the command sequence.

       vde_msocket
              it  has  the  same  semantics  of  socket(2) except that the socket is defined in the scope of the
              network namespace whose descriptor is the first  argument.   The  remaining  arguments  are  those
              defined in socket(2).

       vde_default_stack
              define  the default stack: any successive socket(2) call will use the stack passed as parameter to
              vde_default_stack.  Use NULL to undefine the default stack.

RETURN VALUE

       vde_addstack returns a struct vdestack pointer which is used as  a  descriptor  and  thus  passed  as  an
       argument to the other functions of this library.  NULL is returned in case of error.

       vde_stackcmd  returns  the  exit  status  of  the command.  If the stackcmd argument is a comma separated
       sequence of commands, the execution terminates upon the first command whose exit status is not zero,  and
       the  exit  status  of  that  command  is  returned.   Therefore when vde_stackcmd returns zero the entire
       sequence was successfully executed.

       On success, vde_msocket returns a valid file descriptor.  -1  is  returned  elseways  and  errno  is  set
       appropriately as described in socket(2).

NOTES

       Libvdestack  fails  if  user  namespaces  have  not been configured in the running kernel and enabled for
       users.  In Debian the sysctl knob kernel.unprivileged_userns_clone must be set to 1.

EXAMPLE

       The following excerpt of C code shows the use of libvdestack:

              ...
              int fd;
              int exit_status;
              struct vdestack *stack = vde_addstack("vde://", NULL);
              if (stack == NULL)
                  ... error management
              exit_status = vde_stackcmd(stack,
                        "/bin/ip link set vde0 up;"
                        "/bin/ip addr add 10.0.0.1/24 dev vde0;"
                        "/bin/ip route add default via 10.0.0.254");
              if (exit_status != 0)
                 ... error management
              fd = vde_msocket(stack, AF_INET, SOCK_STREAM, 0);
                 ... fd can be used in any context in which a file descriptor returned by socket(2) can.
              e.g. bind, accept, connect, read/write, send/recv ...
              vde_delstack(stack);

SEE ALSO

       socket(2), vde_plug(1)

BUGS

       Bug reports should be addressed to info@virtualsquare.org

AUTHOR

       VirtualSquare.  Project leader: Renzo Davoli.