The Design and Implementation of the Anykernel and Rump Kernels

A–47
SHMIF(4) NetBSD Kernel Interfaces Manual SHMIF(4)
NAME
shmif -- rump shared memory network interface
SYNOPSIS
#include
int
rump_pub_shmif_create(const char *path, int *ifnum);
DESCRIPTION
The shmif interface uses a memory mapped regular file as a virtual Ethernet
bus. All interfaces connected to the same bus see each others’ traffic.
Using a memory mapped regular file as a bus has two implications: 1) the
bus identifier is not in flat global namespace 2) configuring and using
the interface is possible without superuser privileges on the host (normal
host file access permissions for the bus hold).
It is not possible to directly access the host networking facilities from
a rump virtual kernel using purely shmif. However, traffic can be routed
to another rump kernel instance which provides both shmif and virt(4)
networking.
An shmif interface can be created in two ways:
o Programmatically by calling rump_pub_shmif_create(). The bus pathname
is passed in path. The number of the newly created interface is
available after a succesful call by dereferencing ifnum.
o
Dynamically at runtime with ifconfig(8) or equivalent using the
NetBSD 5.99.48 November 17, 2010 NetBSD 5.99.48