MEDIUM: h2: make h2_frt_transfer_data() copy via an intermediary buffer

The purpose here is also to ensure we can split the lower from the top
layers. The way the CS_FL_MSG_MORE flag is set was updated so that it's
set or cleared upon exit depending on the buffer's remaining contents.

diff --git a/src/mux_h2.c b/src/mux_h2.c
index e93d22b4d97a12c2606efe4f9088b05e9f0e3ee5..cad1ac14463dbdec25db3a4fd70c03e14088eddc 100644 (file)
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -2813,10 +2813,10 @@ static int h2_frt_transfer_data(struct h2s *h2s, struct buffer *buf, int count,
 {
        struct h2c *h2c = h2s->h2c;
        int block1, block2;
-       unsigned int flen = h2c->dfl;
+       unsigned int flen = 0;
        unsigned int chklen = 0;
+       struct buffer *csbuf;
 
-       h2s->cs->flags &= ~CS_FL_RCV_MORE;
        h2c->flags &= ~H2_CF_DEM_SFULL;
 
        /* The padlen is the first byte before data, and the padding appears
@@ -2840,6 +2840,12 @@ static int h2_frt_transfer_data(struct h2s *h2s, struct buffer *buf, int count,
                h2c->dff &= ~H2_F_DATA_PADDED;
        }
 
+       csbuf = h2_get_buf(h2c, &h2s->cs->rxbuf);
+       if (!csbuf) {
+               h2c->flags |= H2_CF_DEM_SALLOC;
+               goto out;
+       }
+
        flen = h2c->dfl - h2c->dpl;
        if (!flen)
                goto end_transfer;
@@ -2847,12 +2853,19 @@ static int h2_frt_transfer_data(struct h2s *h2s, struct buffer *buf, int count,
        if (flen > b_data(&h2c->dbuf)) {
                flen = b_data(&h2c->dbuf);
                if (!flen)
-                       return 0;
+                       goto leave;
+       }
+
+       if (unlikely(b_space_wraps(csbuf))) {
+               /* it doesn't fit and the buffer is fragmented,
+                * so let's defragment it and try again.
+                */
+               b_slow_realign(csbuf, trash.area, 0);
        }
 
        /* chunked-encoding requires more room */
        if (h2s->flags & H2_SF_DATA_CHNK) {
-               chklen = MIN(flen, count);
+               chklen = MIN(flen, b_room(csbuf));
                chklen = (chklen < 16) ? 1 : (chklen < 256) ? 2 :
                        (chklen < 4096) ? 3 : (chklen < 65536) ? 4 :
                        (chklen < 1048576) ? 4 : 8;
@@ -2860,10 +2873,12 @@ static int h2_frt_transfer_data(struct h2s *h2s, struct buffer *buf, int count,
        }
 
        /* does it fit in output buffer or should we wait ? */
-       if (flen + chklen > count) {
-               if (chklen >= count)
-                       goto full;
-               flen = count - chklen;
+       if (flen + chklen > b_room(csbuf)) {
+               if (chklen >= b_room(csbuf)) {
+                       h2c->flags |= H2_CF_DEM_SFULL;
+                       goto leave;
+               }
+               flen = b_room(csbuf) - chklen;
        }
 
        if (h2s->flags & H2_SF_DATA_CHNK) {
@@ -2878,7 +2893,7 @@ static int h2_frt_transfer_data(struct h2s *h2s, struct buffer *buf, int count,
                do {
                        *--beg = hextab[chksz & 0xF];
                } while (chksz >>= 4);
-               b_putblk(buf, beg, str + sizeof(str) - beg);
+               b_putblk(csbuf, beg, str + sizeof(str) - beg);
        }
 
        /* Block1 is the length of the first block before the buffer wraps,
@@ -2890,14 +2905,14 @@ static int h2_frt_transfer_data(struct h2s *h2s, struct buffer *buf, int count,
        block2 = flen - block1;
 
        if (block1)
-               b_putblk(buf, b_head(&h2c->dbuf), block1);
+               b_putblk(csbuf, b_head(&h2c->dbuf), block1);
 
        if (block2)
-               b_putblk(buf, b_peek(&h2c->dbuf, block1), block2);
+               b_putblk(csbuf, b_peek(&h2c->dbuf, block1), block2);
 
        if (h2s->flags & H2_SF_DATA_CHNK) {
                /* emit the CRLF */
-               b_putblk(buf, "\r\n", 2);
+               b_putblk(csbuf, "\r\n", 2);
        }
 
        /* now mark the input data as consumed (will be deleted from the buffer
@@ -2910,7 +2925,8 @@ static int h2_frt_transfer_data(struct h2s *h2s, struct buffer *buf, int count,
 
        if (h2c->dfl > h2c->dpl) {
                /* more data available, transfer stalled on stream full */
-               goto more;
+               h2c->flags |= H2_CF_DEM_SFULL;
+               goto leave;
        }
 
  end_transfer:
@@ -2920,10 +2936,12 @@ static int h2_frt_transfer_data(struct h2s *h2s, struct buffer *buf, int count,
 
        if (h2c->dff & H2_F_DATA_END_STREAM && h2s->flags & H2_SF_DATA_CHNK) {
                /* emit the trailing 0 CRLF CRLF */
-               if (count < 5)
-                       goto more;
+               if (b_room(csbuf) < 5) {
+                       h2c->flags |= H2_CF_DEM_SFULL;
+                       goto leave;
+               }
                chklen += 5;
-               b_putblk(buf, "0\r\n\r\n", 5);
+               b_putblk(csbuf, "0\r\n\r\n", 5);
        }
 
        h2c->rcvd_c += h2c->dpl;
@@ -2931,22 +2949,24 @@ static int h2_frt_transfer_data(struct h2s *h2s, struct buffer *buf, int count,
        h2c->dpl = 0;
        h2c->st0 = H2_CS_FRAME_A; // send the corresponding window update
 
-       /* don't send it before returning data!
-        * FIXME: should we instead try to send it much later, after the
-        * response ? This would require that we keep a copy of it in h2s.
-        */
-       if (h2c->dff & H2_F_DATA_END_STREAM) {
-               h2s->cs->flags |= CS_FL_EOS;
+       if (h2c->dff & H2_F_DATA_END_STREAM)
                h2s->flags |= H2_SF_ES_RCVD;
+
+ leave:
+       /* now transfer possibly pending data from the h2s buffer to the stream buffer */
+       flen = b_xfer(buf, csbuf, count);
+
+ out:
+       if (csbuf && b_data(csbuf))
+               h2s->cs->flags |= CS_FL_RCV_MORE;
+       else {
+               h2s->cs->flags &= ~CS_FL_RCV_MORE;
+               if (h2s->flags & H2_SF_ES_RCVD)
+                       h2s->cs->flags |= CS_FL_EOS;
        }
 
-       return flen + chklen;
- full:
-       flen = chklen = 0;
- more:
-       h2c->flags |= H2_CF_DEM_SFULL;
-       h2s->cs->flags |= CS_FL_RCV_MORE;
-       return flen + chklen;
+       cs_drop_rxbuf(h2s->cs);
+       return flen;
 }
 
 /*