MAJOR: session: introduce embryonic sessions
When an incoming connection request is accepted, a connection
structure is needed to store its state. However we don't want to
fully initialize a session until the data layer is about to be
ready.
As long as the connection is physically stored into the session,
it's not easy to split both allocations.
As such, we only initialize the minimum requirements of a session,
which results in what we call an embryonic session. Then once the
data layer is ready, we can complete the function's initialization.
Doing so avoids buffers allocation and ensures that a session only
sees ready connections.
The frontend's client timeout is used as the handshake timeout. It
is likely that another timeout will be used in the future.
diff --git a/include/types/session.h b/include/types/session.h
index cce55a4..0450163 100644
--- a/include/types/session.h
+++ b/include/types/session.h
@@ -50,7 +50,7 @@
#define SN_FORCE_PRST 0x00000010 /* force persistence here, even if server is down */
#define SN_MONITOR 0x00000020 /* this session comes from a monitoring system */
#define SN_CURR_SESS 0x00000040 /* a connection is currently being counted on the server */
-/* unused: 0x00000080 */
+#define SN_INITIALIZED 0x00000080 /* the session was fully initialized */
#define SN_REDISP 0x00000100 /* set if this session was redispatched from one server to another */
#define SN_CONN_TAR 0x00000200 /* set if this session is turning around before reconnecting */
#define SN_REDIRECTABLE 0x00000400 /* set if this session is redirectable (GET or HEAD) */