MINOR: h2: implement PING frames

Now we can detect and properly parse PING frames as well as emit a
response containing the same payload.

diff --git a/src/mux_h2.c b/src/mux_h2.c
index f7319d0547fee931681b93ddfdad1c1f14553910..0986baae70943bce9e9b5c38aba34795c410e8da 100644 (file)
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -753,6 +753,71 @@ static int h2c_send_goaway_error(struct h2c *h2c, struct h2s *h2s)
        return ret;
 }
 
+/* processes a PING frame and schedules an ACK if needed. The caller must pass
+ * the pointer to the payload in <payload>. Returns > 0 on success or zero on
+ * missing data. It may return an error in h2c.
+ */
+static int h2c_handle_ping(struct h2c *h2c)
+{
+       /* frame length must be exactly 8 */
+       if (h2c->dfl != 8) {
+               h2c_error(h2c, H2_ERR_FRAME_SIZE_ERROR);
+               return 0;
+       }
+
+       /* schedule a response */
+       if (!(h2c->dft & H2_F_PING_ACK))
+               h2c->st0 = H2_CS_FRAME_A;
+       return 1;
+}
+
+/* try to send an ACK for a ping frame on the connection. Returns > 0 on
+ * success, 0 on missing data or one of the h2_status values.
+ */
+static int h2c_ack_ping(struct h2c *h2c)
+{
+       struct buffer *res;
+       char str[17];
+       int ret = -1;
+
+       if (h2c->dbuf->i < 8)
+               return 0;
+
+       if (h2c_mux_busy(h2c, NULL)) {
+               h2c->flags |= H2_CF_DEM_MBUSY;
+               return 0;
+       }
+
+       res = h2_get_mbuf(h2c);
+       if (!res) {
+               h2c->flags |= H2_CF_MUX_MALLOC;
+               h2c->flags |= H2_CF_DEM_MROOM;
+               return 0;
+       }
+
+       memcpy(str,
+              "\x00\x00\x08"     /* length : 8 (same payload) */
+              "\x06" "\x01"      /* type   : 6, flags : ACK   */
+              "\x00\x00\x00\x00" /* stream ID */, 9);
+
+       /* copy the original payload */
+       h2_get_buf_bytes(str + 9, 8, h2c->dbuf, 0);
+
+       ret = bo_istput(res, ist2(str, 17));
+       if (unlikely(ret <= 0)) {
+               if (!ret) {
+                       h2c->flags |= H2_CF_MUX_MFULL;
+                       h2c->flags |= H2_CF_DEM_MROOM;
+                       return 0;
+               }
+               else {
+                       h2c_error(h2c, H2_ERR_INTERNAL_ERROR);
+                       return 0;
+               }
+       }
+       return ret;
+}
+
 /* process Rx frames to be demultiplexed */
 static void h2_process_demux(struct h2c *h2c)
 {
@@ -838,6 +903,14 @@ static void h2_process_demux(struct h2c *h2c)
                /* Only H2_CS_FRAME_P and H2_CS_FRAME_A here */
 
                switch (h2c->dft) {
+               case H2_FT_PING:
+                       if (h2c->st0 == H2_CS_FRAME_P)
+                               ret = h2c_handle_ping(h2c);
+
+                       if (h2c->st0 == H2_CS_FRAME_A)
+                               ret = h2c_ack_ping(h2c);
+                       break;
+
                        /* FIXME: implement all supported frame types here */
                default:
                        /* drop frames that we ignore. They may be larger than