revalidator: Simplify push_dump_ops__().

Commit acaa8dac49 (revalidator: Eliminate duplicate flow handling.)
ensured that a ukey will always exist for a given flow, even if it is
about to be deleted. This means that push_dump_ops__() no longer needs
to handle the case where there is no ukey. This commit removes the
redundant code.

Signed-off-by: Joe Stringer <joestringer@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>
util: create a copy of program_name

Commit 8a9562 ("dpif-netdev: Add DPDK netdev.") reversed sequence
in which set_program_name() and proctitle_init() functions are
called.  This introduced a regression where program_name and argv_start
would point to exactly the same memory (previously both of these
pointers were pointing to different memory locations because
proctitle_init() would have beforehand created a copy of argv[0]
for the succeeding set_program_name() call).

This regression on my system caused ovs-vswitchd monitoring process to
show up without process name:

...  00:00:00 : monitoring pid 26308 (healthy)

Ps output was lacking process name because following code was
using overlapping memory for source and target buffer:.

proctitle_set(const char *format, ...)
{
    ...
    n = snprintf(argv_start, argv_size, "%s: ", program_name);

Overall C99 and POSIX standards state that behavior is undefined
if source and target buffers overlap.

Signed-Off-By: Ansis Atteka <aatteka@nicira.com>
Acked-By: Ben Pfaff <blp@nicira.com>
userspace: add support for pop_eth and push_eth actions

These actions will allow L2->L3 and L3->L2 switching, and are supposed
to be added to flows installed in the datapath transparently by
ovs-vswitchd.

Signed-off-by: Lorand Jakab <lojakab@cisco.com>
userspace: add layer 3 flow and switching support

This commit relaxes the assumption that all packets have an Ethernet
header, and adds support for layer 3 flows.  For each packet received on
the Linux kernel datapath the l2 and l3 members of struct ofpbuf are
intialized appropriately, and some functions now expect this (notably
flow_extract()), in order to differentiate between layer 2 and layer 3
packets.  struct flow has now a new 'base_layer' member, because we
cannot assume that a flow has no Ethernet header when eth_src and
eth_dst are 0.  For layer 3 packets, the protocol type is still stored
in the eth_type member.

Switching L2->L3 and L3->L2 are both implemented by adding the pop_eth
and push_eth actions respectively when a transition is detected.  The
push_eth action puts 0s on both source and destination MACs.  These
addresses can be modified with mod_dl_dst and mod_dl_src actions.

Added new prerequisite MFP_ETHERNET for fields MFF_ETH_SRC, MFF_ETH_DST,
MFF_VLAN_TCI, MFF_DL_VLAN, MFF_VLAN_VID and MFF_DL_VLAN_PCP.

Signed-off-by: Lorand Jakab <lojakab@cisco.com>
datapath: add layer 3 flow/port support

Implementation of the pop_eth and push_eth actions in the kernel, and
layer 3 flow support.

Signed-off-by: Lorand Jakab <lojakab@cisco.com>