tun(4) and tap(4) share the same general management interface and have a lot
in common. Bugs exist in tap(4) that have been fixed in tun(4), and
vice-versa. Let's reduce the maintenance requirements by merging them
together and using flags to differentiate between the three interface types
(tun, tap, vmnet).
This fixes a couple of tap(4)/vmnet(4) issues right out of the gate:
- tap devices may no longer be destroyed while they're open [0]
- VIMAGE issues already addressed in tun by kp
[0] emaste had removed an easy-panic-button in r240938 due to devdrn
blocking. A naive glance over this leads me to believe that this isn't quite
complete -- destroy_devl will only block while executing d_* functions, but
doesn't block the device from being destroyed while a process has it open.
The latter is the intent of the condvar in tun, so this is "fixed" (for
certain definitions of the word -- it wasn't really broken in tap, it just
wasn't quite ideal).
ifconfig(8) also grew the ability to map an interface name to a kld, so
that `ifconfig {tun,tap}0` can continue to autoload the correct module, and
`ifconfig vmnet0 create` will now autoload the correct module. This is a
low overhead addition.
(MFC commentary)
This may get MFC'd if many bugs in tun(4)/tap(4) are discovered after this,
and how critical they are. Changes after this are likely easily MFC'd
without taking this merge, but the merge will be easier.
I have no plans to do this MFC as of now.
Reviewed by: bcr (manpages), tuexen (testing, syzkaller/packetdrill)
Input also from: melifaro
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D20044
type to any value. This can cause page faults and panics due to accessing
uninitialized fields in the "struct ifnet" which are specific to the network
device type.
MFC after: 1 week
Found by: jau@iki.fi
PR: 223767
Sponsored by: Mellanox Technologies
to how they differ. This will assist users in selecting which interface
is more appropriate for their purposes.
Approved by: grog (co-mentor)
MFC after: 2 week
Make devfs cloning a sysctl/tunable which defaults to on.
If devfs cloning is enabled, only the super-user may create
tun(4)/tap(4)/vmnet(4) instances. Devfs cloning is still enabled by
default; it may be disabled from the loader or via sysctl with
"net.link.tap.devfs_cloning" and "net.link.tun.devfs_cloning".
Disabling its use affects potentially all tun(4)/tap(4) consumers
including OpenSSH, OpenVPN and VMware.
PR: 105228 (potentially also 90413, 105570)
Submitted by: Landon Fuller
Tested by: Andrej Tobola
Approved by: core (rwatson)
MFC after: 4 weeks
