netdev: New function netdev_ref().

I suspect that this makes it easier to make sure that a netdev stays open
as long as needed in some cases where a module needs access to a netdev
opened by some higher-level module.

CC: Ethan Jackson <ethan@nicira.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
cfm: Implement "demand mode".

The new CFM "demand mode" (named after BFD's demand mode) uses
data traffic to indicate interface liveness.  It's helpful on
heavily congested networks where CCMs may be dropped.

Signed-off-by: Ethan Jackson <ethan@nicira.com>
add minimal NetBSD support

mostly ride on the existing FreeBSD support.

Signed-off-by: YAMAMOTO Takashi <yamt@mwd.biglobe.ne.jp>
Signed-off-by: Ben Pfaff <blp@nicira.com>
keep "kernel name" for each netdev

where interface renaming is not supported (NetBSD), remember both of
our netdev name and the correspoinding kernel name separately.
the latter is necessary to talk with kernel using interface names.
eg. ifioctls, bpf

XXX there should be a proper way to query kernel name.
Ben Pfaff suggested ovs-appctl but this patch doesn't implement it. (yet)

Signed-off-by: YAMAMOTO Takashi <yamt@mwd.biglobe.ne.jp>
Signed-off-by: Ben Pfaff <blp@nicira.com>
netdev-bsd: NetBSD: keep a AF_LINK socket open

this will be used for get_stats and set_etheraddr

Signed-off-by: YAMAMOTO Takashi <yamt@mwd.biglobe.ne.jp>
Signed-off-by: Ben Pfaff <blp@nicira.com>
missing ifdef netbsd guard for af_link_sock

pointed out by Ed Maste

Signed-off-by: YAMAMOTO Takashi <yamt@mwd.biglobe.ne.jp>
Signed-off-by: Ben Pfaff <blp@nicira.com>
implement set_etheraddr for NetBSD

Signed-off-by: YAMAMOTO Takashi <yamt@mwd.biglobe.ne.jp>
implement get_stats for NetBSD

Signed-off-by: YAMAMOTO Takashi <yamt@mwd.biglobe.ne.jp>
Signed-off-by: Ben Pfaff <blp@nicira.com>
some NetBSD related documentation changes

Signed-off-by: YAMAMOTO Takashi <yamt@mwd.biglobe.ne.jp>
Signed-off-by: Ben Pfaff <blp@nicira.com>
implement get_next_hop for NetBSD

Signed-off-by: YAMAMOTO Takashi <yamt@mwd.biglobe.ne.jp>
Signed-off-by: Ben Pfaff <blp@nicira.com>
factor out a function to extract stats from if_data to netdev_stats.

suggested by Ed Maste.

Signed-off-by: YAMAMOTO Takashi <yamt@mwd.biglobe.ne.jp>
Signed-off-by: Ben Pfaff <blp@nicira.com>
INSTALL: update for NetBSD

Signed-off-by: YAMAMOTO Takashi <yamt@mwd.biglobe.ne.jp>
Signed-off-by: Ben Pfaff <blp@nicira.com>