The number of stick-counter entries usable by track-sc rules is currently
set at build time. There is no good value for this since the vast majority
of users don't need any, most need only a few and rare users need more.
Adding more counters for everyone increases memory and CPU usages for no
reason.

This patch moves the per-session and per-stream arrays to a pool of a size
defined at boot time. This way it becomes possible to set the number of
entries at boot time via a new global setting "tune.stick-counters" that
sets the limit for the whole process. When not set, the MAX_SESS_STR_CTR
value still applies, or 3 if not set, as before.

It is also possible to lower the value to 0 to save a bit of memory if
not used at all.

Note that a few low-level sample-fetch functions had to be protected due
to the ability to use sample-fetches in the global section to set some
variables.

Idle connections do not work on 32-bit machines due to an alignment issue
causing the connection nodes to be indexed with their lower 32-bits set to
zero and the higher 32 ones containing the 32 lower bitss of the hash. The
cause is the use of ebmb_node with an aligned data, as on this platform
ebmb_node is only 32-bit aligned, leaving a hole before the following hash
which is a uint64_t:

  $ pahole -C conn_hash_node ./haproxy
  struct conn_hash_node {
        struct ebmb_node           node;                 /*     0    20 */

        /* XXX 4 bytes hole, try to pack */

        int64_t                    hash;                 /*    24     8 */
        struct connection *        conn;                 /*    32     4 */

        /* size: 40, cachelines: 1, members: 3 */
        /* sum members: 32, holes: 1, sum holes: 4 */
        /* padding: 4 */
        /* last cacheline: 40 bytes */
  };

Instead, eb64 nodes should be used when it comes to simply storing a
64-bit key, and that is what this patch does.

For backports, a variant consisting in simply marking the "hash" member
with a "packed" attribute on the struct also does the job (tested), and
might be preferable if the fix is difficult to adapt. Only 2.6 and 2.5
are affected by this.

That's similar to what was done for conn_streams and connections. The
flags were only set exactly when the relevant pointers were allocated,
so better test the pointer than the flag and stop setting the flag.

This is 28th iteration of typo fixes

For now, these addresses are never set. But the idea is to be able to set
client source and destination addresses at the session level without
updating the connection ones.

Functions to fill these addresses have been added: sess_get_src() and
sess_get_dst(). If not already set, these functions relies on
conn_get_src() and conn_get_dst() to fill session addresses.

And just like for conncetions, sess_src() and sess_dst() may be used to get
source and destination addresses. However, if not set, the corresponding
address from the underlying client connection is returned. When this
happens, the addresses is filled in the connection object.

This patch replaces all advanced data type aliases on
stktable_data_cast calls by standard types.

This way we could call the same stktable_data_cast
regardless of the used advanced data type as long they
are using the same std type.

It also removes all the advanced data type aliases.

Move the session_list attach point in an anonymous union. This member is
only used for backend connections. This commit is in preparation for the
support of stopping frontend idling connections which will add another
member to the union.

This change means that a special care must be taken to be sure that only
backend connections manipulate the session_list. A few BUG_ON has been
added as special guard to prevent from misuse.

The current "ADD" vs "ADDQ" is confusing because when thinking in terms
of appending at the end of a list, "ADD" naturally comes to mind, but
here it does the opposite, it inserts. Several times already it's been
incorrectly used where ADDQ was expected, the latest of which was a
fortunate accident explained in 6fa922562 ("CLEANUP: stream: explain
why we queue the stream at the head of the server list").

Let's use more explicit (but slightly longer) names now:

   LIST_ADD        ->       LIST_INSERT
   LIST_ADDQ       ->       LIST_APPEND
   LIST_ADDED      ->       LIST_INLIST
   LIST_DEL        ->       LIST_DELETE

The same is true for MT_LISTs, including their "TRY" variant.
LIST_DEL_INIT keeps its short name to encourage to use it instead of the
lazier LIST_DELETE which is often less safe.

The change is large (~674 non-comment entries) but is mechanical enough
to remain safe. No permutation was performed, so any out-of-tree code
can easily map older names to new ones.

The list doc was updated.

It's been too short for quite a while now and is now full. It's still
time to extend it to 32-bits since we have room for this without
wasting any space, so we now gained 16 new bits for future flags.

The values were not reassigned just in case there would be a few
hidden u16 or short somewhere in which these flags are placed (as
it used to be the case with stream->pending_events).

The patch is tagged MEDIUM because this required to update the task's
process() prototype to use an int instead of a short, that's quite a
bunch of places.

Remove ebmb_node entry from struct connection and create a dedicated
struct conn_hash_node. struct connection contains now only a pointer to
a conn_hash_node, allocated only for connections where target is of type
OBJ_TYPE_SERVER. This will reduce memory footprints for every
connections that does not need http-reuse such as frontend connections.