datapath: Allow pop and push MPLS actions after pop VLAN

This patch loosens the restrictions surrounding push and pop MPLS actions
such that they will be allowed after a pop VLAN action if the inner
ethernet type is acceptable for pop and push MPLS actions. This implies
that there is only one VLAN tag present.

Some analysis of logic of this change is as follows:

    The purpose of tracking vlan_tci is to allow prohibition of push
    and pop MPLS actions in the presence of a VLAN. In this scenario
    the VLAN_TAG_PRESENT bit of vlan_tci is set and eth_type is that of
    the packet with the outermost VLAN tag removed.

    A pop VLAN action may clear vlan_tci as it removes the outermost
    VLAN tag and the push and pop MPLS logic may rely on eth_type for
    their prohibition logic.

    This will not allow push and pop MPLS on packets with multiple VLAN
    tags, regardless of if they are all remove using POP VLAN, as there
    is no mechanism to expose the inner ethernet type beyond that of
    the outermost VLAN tag.

Suggested-by: Jesse Gross <jgross@nicira.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Jesse Gross <jesse@nicira.com>
revalidator: Improve optimization to skip revalidation.

The should_revalidate() optimisation introduced with commit 698ffe3623
(revalidator: Only revalidate high-throughput flows.) was a little
aggressive, occasionally deleting flows even when OVS is quite capable
of performing full revalidation.

This commit modifies the logic to:
* Firstly, check if we are likely to handle full revalidation, and
  attempt that instead.
* Secondly, fall back to the existing flow throughput estimations to
  determine whether to revalidate the flow or just delete it.

VMware-BZ: #1271926

Signed-off-by: Joe Stringer <joestringer@nicira.com>
Acked-by: Alex Wang <alexw@nicira.com>
INSTALL.Fedora, INSTALL.RHEL: Make instructions more explicit.

Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Flavio Leitner <fbl@redhat.com>
Acked-by: Pritesh Kothari <pritesh.kothari@cisco.com>
INSTALL.DPDK: fix a typo in remote line

Signed-off-by: Flavio Leitner <fbl@redhat.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Pritesh Kothari <pritesh.kothari@cisco.com>
INSTALL: Mention conflict with NET_IPGRE setting before Linux 3.11.

I found when reconfiguring my kernel that if I turned on NET_IPGRE, GRE
tunnels no longer worked.

Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>
netlink-socket: Work around upstream kernel Netlink bug.

The upstream kernel net/netlink/af_netlink.c netlink_recvmsg() contains the
following code to refill the Netlink socket buffer with more dump skbs
while a dump is in progress:

	if (nlk->cb && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
		ret = netlink_dump(sk);
		if (ret) {
			sk->sk_err = ret;
			sk->sk_error_report(sk);
		}
	}

The netlink_dump() function that this calls returns a negative number on
error, the convention used throughout the kernel, and thus sk->sk_err
receives a negative value on error.

However, sk->sk_err is supposed to contain either 0 or a positive errno
value, as one can see from a quick "grep" through net for 'sk_err =', e.g.:

    ipv4/tcp.c:2067:		sk->sk_err = ECONNRESET;
    ipv4/tcp.c:2069:		sk->sk_err = ECONNRESET;
    ipv4/tcp_input.c:4106:		sk->sk_err = ECONNREFUSED;
    ipv4/tcp_input.c:4109:		sk->sk_err = EPIPE;
    ipv4/tcp_input.c:4114:		sk->sk_err = ECONNRESET;
    netlink/af_netlink.c:741:			sk->sk_err = ENOBUFS;
    netlink/af_netlink.c:1796:			sk->sk_err = ENOBUFS;
    packet/af_packet.c:2476:		sk->sk_err = ENETDOWN;
    unix/af_unix.c:341:			other->sk_err = ECONNRESET;
    unix/af_unix.c:407:				skpair->sk_err = ECONNRESET;

The result is that the next attempt to receive from the socket will return
the error to userspace with the wrong sign.

(The root of the error in this case is that multiple threads are attempting
to read a single flow dump from a shared fd.  That should work, but the
kernel has an internal race that can result in one or more of those threads
hitting the EINVAL case at the start of netlink_dump().  The EINVAL is
harmless in this case and userspace should be able to ignore it, but
reporting the EINVAL as if it were a 22-byte message received in userspace
throws a real wrench in the works.)

This bug makes me think that there are probably not many programs doing
multithreaded Netlink dumps.  Maybe it is good that we are considering
other approaches.

VMware-BZ: #1255704
Reported-by: Mihir Gangar <gangarm@vmware.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Alex Wang <alexw@nicira.com>
datapath: Additional logging for -EINVAL on flow setups.

There are many possible ways that a flow can be invalid so we've
added logging for most of them. This adds logs for the remaining
possible cases so there isn't any ambiguity while debugging.

CC: Federico Iezzi <fiezzi@enter.it>
Signed-off-by: Jesse Gross <jesse@nicira.com>
Acked-by: Thomas Graf <tgraf@noironetworks.com>
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>
util: Suppress a warning by adding CONST_CAST

Suppress a gcc warning which was introduced by
commit e0b48482c16b6eaa7f14d8c7e7c6275528881b9e.
("util: create a copy of program_name")
I guess MSVC doesn't have a corresponding warning.

Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Acked-by: Lorand Jakab <lojakab@cisco.com>
dpif-netdev: Use cmap instead of hmap.

This requires less locking and makes introducing lockless classifier
lookups possible.

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>
lib/hash: Abstract hash interface.

Use generic names hash_add() and hash_finish() instead of mhash_*
equivalents.  This makes future changes to hash implentations more
localized.

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>
ovs-atomic: Use explicit memory order for ovs_refcount.

Use explicit variants of atomic operations for the ovs_refcount to
avoid the overhead of the default memory_order_seq_cst.

Adding a reference requires no memory ordering, as the calling thread
is already assumed to have protected access to the object being
reference counted.  Hence, memory_order_relaxed is used for
ovs_refcount_ref().  ovs_refcount_read() does not change the reference
count, so it can also use memory_order_relaxed.

Unreferencing an object needs a release barrier, so that none of the
accesses to the protected object are reordered after the atomic
decrement operation.  Additionally, an explicit acquire barrier is
needed before the object is recycled, to keep the subsequent accesses
to the object's memory from being reordered before the atomic
decrement operation.

This patch follows the memory ordering and argumentation discussed
here:

http://www.chaoticmind.net/~hcb/projects/boost.atomic/doc/atomic/usage_examples.html

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>
lib/ovs-atomic: Add atomic compare_exchange.

Add support for atomic compare_exchange operations.

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>
lib/ovs-atomic: Add ovs_refcount_unref_relaxed(), ovs_refcount_try_ref_rcu().

When a reference counted object is also RCU protected the deletion of
the object's memory is always postponed.  This allows
memory_order_relaxed to be used also for unreferencing, as RCU
quiescing provides a full memory barrier (it has to, or otherwise
there could be lingering accesses to objects after they are recycled).

Also, when access to the reference counted object is protected via a
mutex or a lock, the locking primitives provide the required memory
barrier functionality.

Also, add ovs_refcount_try_ref_rcu(), which takes a reference only if
the refcount is non-zero and returns true if a reference was taken,
false otherwise.  This can be used in combined RCU/refcount scenarios
where we have an RCU protected reference to an refcounted object, but
which may be unref'ed at any time.  If ovs_refcount_try_ref_rcu()
fails, the object may still be safely used until the current thread
quiesces.

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>
Use ovs_refcount_unref_relaxed.

After a quick analysis, in most cases the access to refcounted objects
is clearly protected either with an explicit lock/mutex, or RCU. there
are only a few places where I left a call to ovs_refcount_unref().
Upon closer analysis it may well be that those could also use the
relaxed form.

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>
ofproto-dpif: Use ovs_refcount_try_ref_rcu().

This is a prerequisite step in making the classifier lookups lockless.
If taking a reference fails, we do the lookup again, as a new (lower
priority) rule may now match instead.

Also remove unwildcarding dl_type and nw_frag, as these are already
taken care of by xlate_actions().

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>
lib/classifier: Remove unused typedef cls_cb_func.

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>
ovsdb: Frees database memory on ovsdb process cleanup.

This fixes valgrind errors.

Signed-off-by: Ryan Wilson <wryan@nicira.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
util: fix compile warnings

This patch fixes two compile warnings introduced by commit
64b73291 ("util: create a copy of program_name"):
1. ../lib/util.c:457:5: error: passing argument 1 of 'free'
   discards 'const' qualifier from pointer target type; And
2. ../lib/util.c:463:5: error: ISO C90 forbids mixed declarations
   and code [-Werror=declaration-after-statement] (affected only
   branch-2.3 that is C90 compliant and not the master)

Reported-By: Joe Stringer <jstringer@nicira.com>
Reported-By: Lorand Jakab <lojakab@cisco.com>
Signed-Off-By: Ansis Atteka <aatteka@nicira.com>
Acked-by: Joe Stringer <joestringer@nicira.com>