MINOR: muxes: Report the Last read with a dedicated flag

For conveniance, in HTTP muxes (h1 and h2), the end of the stream and the end of
the message are reported the same way to the stream, by setting the flag
CS_FL_EOS. In the stream-interface, when CS_FL_EOS is detected, a shutdown for
read is reported on the channel side. This is historical. With the legacy HTTP
layer, because the parsing is done by the stream in HTTP analyzers, the EOS
really means a shutdown for read.

Most of time, for muxes h1 and h2, it works pretty well, especially because the
keep-alive is handled by the muxes. The stream is only used for one
transaction. So mixing EOS and EOM is good enough. But not everytime. For now,
client aborts are only reported if it happens before the end of the request. It
is an error and it is properly handled. But because the EOS was already
reported, client aborts after the end of the request are silently
ignored. Eventually an error can be reported when the response is sent to the
client, if the sending fails. Otherwise, if the server does not reply fast
enough, an error is reported when the server timeout is reached. It is the
expected behaviour, excpect when the option abortonclose is set. In this case,
we must report an error when the client aborts. But as said before, this event
can be ignored. So to be short, for now, the abortonclose is broken.

In fact, it is a design problem and we have to rethink all channel's flags and
probably the conn-stream ones too. It is important to split EOS and EOM to not
loose information anymore. But it is not a small job and the refactoring will be
far from straightforward.

So for now, temporary flags are introduced. When the last read is received, the
flag CS_FL_READ_NULL is set on the conn-stream. This way, we can set the flag
SI_FL_READ_NULL on the stream interface. Both flags are persistant. And to be
sure to wake the stream, the event CF_READ_NULL is reported. So the stream will
always have the chance to handle the last read.

This patch must be backported to 1.9 because it will be used by another patch to
fix the option abortonclose.

include/types/connection.h

@@ -87,6 +87,7 @@ enum {
 	CS_FL_ERR_PENDING   = 0x00000800,  /* An error is pending, but there's still data to be read */
 	CS_FL_EOS           = 0x00001000,  /* End of stream delivered to data layer */
 	CS_FL_REOS          = 0x00002000,  /* End of stream received (buffer not empty) */
+	CS_FL_READ_NULL     = 0x00004000,  /* Last read received */
 	CS_FL_WAIT_FOR_HS   = 0x00010000,  /* This stream is waiting for handhskae */
 	CS_FL_KILL_CONN     = 0x00020000,  /* must kill the connection when the CS closes */
 

include/types/stream_interface.h

@@ -72,7 +72,7 @@ enum {
 	SI_FL_NOLINGER   = 0x00000080,  /* may close without lingering. One-shot. */
 	SI_FL_NOHALF     = 0x00000100,  /* no half close, close both sides at once */
 	SI_FL_SRC_ADDR   = 0x00001000,  /* get the source ip/port with getsockname */
-	/* unused:         0x00002000 */
+	SI_FL_READ_NULL  = 0x00000200,   /* Last read reported */
 	SI_FL_WANT_GET   = 0x00004000,  /* a stream-int would like to get some data from the buffer */
 	SI_FL_CLEAN_ABRT = 0x00008000,  /* SI_FL_ERR is used to report aborts, and not SHUTR */
 

src/mux_h1.c

@@ -1777,7 +1777,7 @@ static int h1_recv(struct h1c *h1c)
 		h1_wake_stream_for_recv(h1s);
 
 	if (conn_xprt_read0_pending(conn) && h1s && h1s->cs)
-		h1s->cs->flags |= CS_FL_REOS;
+		h1s->cs->flags |= (CS_FL_REOS|CS_FL_READ_NULL);
 	if (!b_data(&h1c->ibuf))
 		h1_release_buf(h1c, &h1c->ibuf);
 	else if (!buf_room_for_htx_data(&h1c->ibuf))
@@ -1885,7 +1885,7 @@ static int h1_process(struct h1c * h1c)
 		if (h1c->flags & H1C_F_CS_ERROR || conn->flags & CO_FL_ERROR)
 			flags |= CS_FL_ERROR;
 		if (conn_xprt_read0_pending(conn))
-			flags |= CS_FL_EOS;
+			flags |= (CS_FL_REOS|CS_FL_READ_NULL);
 		h1s->cs->flags |= flags;
 		h1s->cs->data_cb->wake(h1s->cs);
 	}

src/mux_h2.c

@@ -1423,7 +1423,7 @@ static void h2_wake_some_streams(struct h2c *h2c, int last, uint32_t flags)
 		flags |= CS_FL_ERR_PENDING;
 
 	if (conn_xprt_read0_pending(h2c->conn))
-		flags |= CS_FL_REOS;
+		flags |= (CS_FL_REOS|CS_FL_READ_NULL);
 
 	/* Wake all streams with ID > last */
 	node = eb32_lookup_ge(&h2c->streams_by_id, last + 1);

src/mux_pt.c

@@ -255,7 +255,7 @@ static size_t mux_pt_rcv_buf(struct conn_stream *cs, struct buffer *buf, size_t
 	if (conn_xprt_read0_pending(cs->conn)) {
 		if (ret == 0)
 			cs->flags &= ~(CS_FL_RCV_MORE | CS_FL_WANT_ROOM);
-		cs->flags |= CS_FL_EOS;
+		cs->flags |= (CS_FL_EOS|CS_FL_READ_NULL);
 	}
 	if (cs->conn->flags & CO_FL_ERROR) {
 		if (ret == 0)
@@ -298,7 +298,7 @@ static int mux_pt_rcv_pipe(struct conn_stream *cs, struct pipe *pipe, unsigned i
 
 	ret = cs->conn->xprt->rcv_pipe(cs->conn, pipe, count);
 	if (conn_xprt_read0_pending(cs->conn))
-		cs->flags |= CS_FL_EOS;
+		cs->flags |= (CS_FL_EOS|CS_FL_READ_NULL);
 	if (cs->conn->flags & CO_FL_ERROR)
 		cs->flags |= CS_FL_ERROR;
 	return (ret);

src/stream_interface.c

@@ -594,6 +594,17 @@ static int si_cs_process(struct conn_stream *cs)
 		oc->flags |= CF_WRITE_NULL;
 	}
 
+	/* The last read was received but not reported to the channel
+	 * (CS_FL_READ_NULL set but not SI_FL_READ_NULL). So do it, even if the
+	 * EOS was already reported.
+	 *
+	 * NOTE: It is a temporary fix to handle client aborts.
+	 */
+	if (cs->flags & CS_FL_READ_NULL && !(si->flags & SI_FL_READ_NULL)) {
+		si->flags |= SI_FL_READ_NULL;
+		ic->flags |= CF_READ_NULL;
+	}
+
 	/* Second step : update the stream-int and channels, try to forward any
 	 * pending data, then possibly wake the stream up based on the new
 	 * stream-int status.