packets: Use WORDS_BIGENDIAN for struct geneve_opt.

The macro LITTLE_ENDIAN is a constant, not a test for endianness,
so it doesn't actually tell us anything about the machine.
WORDS_BIGENDIAN is both correct and defined by configure so it is
more portable.

Reported-by: Ben Pfaff <blp@nicira.com>
Signed-off-by: Jesse Gross <jesse@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>
xenserver: Turn on SSE and SSE2 for the build, for atomic 64-bit ops.

The ovs-atomic-i586 implementation of atomic operations can implement
64-bit atomics more efficiently when SSE is supported.  XenServer runs only
on 64-bit capable processors, in 32-bit mode, so we know on XenServer that
SSE and SSE2 are supported because they are architectural for amd64.  Thus,
this commit enables SSE and SSE2 when building for XenServer to get the
improved atomics support.

I tested that this successfully adds -msse -msse2 to the compiler flags
inside a XenServer DDK, but I didn't actually run it on a real XenServer
install.

Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Jarno Rajahalme <jrajahalme@nicira.com>
Change Travis CI notification email to ljakab@ac.upc.edu
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>