BUG/MINOR: mux-h1: Fix conditions to know whether or not we may receive data

The h1_recv_allowed() function is inherited from the h2 multiplexer. But for the
h1, conditions to know if we may receive data are less complex because there is
no multiplexing and because data are not parsed when received. So now, following
rules are respected :

 * if an error or a shutdown for reads was detected on the connection we must
   not attempt to receive
 * if the input buffer failed to be allocated or is full, we must not try to
   receive
 * if the input processing is busy waiting for the output side, we may attempt
   to receive
 * otherwise must may not attempt to receive

This patch must be backported as far as 1.9.

diff --git a/src/mux_h1.c b/src/mux_h1.c
index 41959fdcdff54f575d6315800f5e4c2786e494dc..f091594131c31002ce1139d25e77495c11c93d6b 100644 (file)
--- a/src/mux_h1.c
+++ b/src/mux_h1.c
@@ -349,31 +349,23 @@ static void h1_trace(enum trace_level level, uint64_t mask, const struct trace_s
 /* functions below are for dynamic buffer management */
 /*****************************************************/
 /*
- * Indicates whether or not the we may call the h1_recv() function to
- * attempt to receive data into the buffer and/or parse pending data. The
- * condition is a bit complex due to some API limits for now. The rules are the
- * following :
- *   - if an error or a shutdown was detected on the connection and the buffer
- *     is empty, we must not attempt to receive
- *   - if the input buffer failed to be allocated, we must not try to receive
- *      and we know there is nothing pending
- *   - if no flag indicates a blocking condition, we may attempt to receive,
- *     regardless of whether the input buffer is full or not, so that only de
- *     receiving part decides whether or not to block. This is needed because
- *     the connection API indeed prevents us from re-enabling receipt that is
- *     already enabled in a polled state, so we must always immediately stop as
- *     soon as the mux can't proceed so as never to hit an end of read with data
- *     pending in the buffers.
+ * Indicates whether or not we may receive data. The rules are the following :
+ *   - if an error or a shutdown for reads was detected on the connection we
+       must not attempt to receive
+ *   - if the input buffer failed to be allocated or is full , we must not try
+ *     to receive
+ *   - if he input processing is busy waiting for the output side, we may
+ *     attemp to receive
  *   - otherwise must may not attempt to receive
  */
 static inline int h1_recv_allowed(const struct h1c *h1c)
 {
-       if (b_data(&h1c->ibuf) == 0 && (h1c->flags & (H1C_F_CS_ERROR|H1C_F_CS_SHUTDOWN))) {
-               TRACE_DEVEL("recv not allowed because of (error|shudown) on h1c", H1_EV_H1C_RECV|H1_EV_H1C_BLK, h1c->conn);
+       if (h1c->flags & H1C_F_CS_ERROR) {
+               TRACE_DEVEL("recv not allowed because of error on h1c", H1_EV_H1C_RECV|H1_EV_H1C_BLK, h1c->conn);
                return 0;
        }
 
-       if (h1c->conn->flags & CO_FL_ERROR || conn_xprt_read0_pending(h1c->conn)) {
+       if (h1c->conn->flags & (CO_FL_ERROR|CO_FL_SOCK_RD_SH)) {
                TRACE_DEVEL("recv not allowed because of (error|read0) on connection", H1_EV_H1C_RECV|H1_EV_H1C_BLK, h1c->conn);
                return 0;
        }