ovsdb-client: Fix recently introduced svec_sort() bug.

Commit 66980be9 (ovsdb-client: Avoid assertion with multiple databases.)
passed in a pointer to an svec pointer, when it should have just been an
svec pointer.  This corrects the bug.

Signed-off-by: Justin Pettit <jpettit@nicira.com>
ovs-ofctl: Fix bad info in comment on transact_multiple_noreply().

Cut-and-paste error I guess.

Signed-off-by: Ben Pfaff <blp@nicira.com>
datapath: Free skb dropped by lisp_tnl_send().

vport->send functions must free the skbs they themselves report as
dropped (return 0).

Signed-off-by: Jarno Rajahalme <jarno.rajahalme@nsn.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
bfd: Implement Bidirectional Forwarding Detection.

Traditionally, Open vSwitch has used a variant of 802.1ag "CFM" for
interface liveness detection.  This has served us well until now,
but has several serious drawbacks which have steadily become more
inconvenient.  First, the 802.1ag standard does not implement
several useful features forcing us to (optionally) break
compatibility.  Second, 802.1.ag is not particularly popular
outside of carrier grade networking equipment.  Third, 802.1ag is
simply quite awkward.

In an effort to solve the aforementioned problems, this patch
implements BFD which is ubiquitous, well designed, straight
forward, and implements required features in a standard way.  The
initial cut of the protocol focuses on getting the basics of the
specification correct, leaving performance optimizations, and
advanced features as future work.  The protocol should be
considered experimental pending future testing.

Signed-off-by: Ethan Jackson <ethan@nicira.com>