MEDIUM: h3: properly manage tx buffers for large data
Properly handle tx buffers management in h3 data sending. If there is
not enough contiguous space, the buffer is first realigned. If this is
not enough, the stream is flagged with QC_SF_BLK_MROOM waiting for the
buffer to be emptied.
If a frame on a stream is successfully pushed for sending, the stream is
called if it was flagged with QC_SF_BLK_MROOM.
diff --git a/src/h3.c b/src/h3.c
index a94b24b..602627f 100644
--- a/src/h3.c
+++ b/src/h3.c
@@ -534,8 +534,7 @@
struct buffer *res;
size_t total = 0;
struct htx *htx;
- int bsize, fsize;
- int frame_length_size; /* size in bytes of frame length varint field */
+ int bsize, fsize, hsize;
struct htx_blk *blk;
enum htx_blk_type type;
@@ -557,19 +556,34 @@
if (fsize > count)
fsize = count;
- frame_length_size = quic_int_getsize(fsize);
+ /* h3 DATA headers : 1-byte frame type + varint frame length */
+ hsize = 1 + QUIC_VARINT_MAX_SIZE;
- b_reset(&outbuf);
- outbuf = b_make(b_tail(res), b_contig_space(res), 0, 0);
+ while (1) {
+ b_reset(&outbuf);
+ outbuf = b_make(b_tail(res), b_contig_space(res), 0, 0);
+ if (b_size(&outbuf) > hsize || !b_space_wraps(res))
+ break;
+ b_slow_realign(res, trash.area, b_data(res));
+ }
- if (1 + fsize + frame_length_size > b_room(&outbuf))
- ABORT_NOW();
+ /* not enough room for headers and at least one data byte, block the
+ * stream
+ */
+ if (b_size(&outbuf) <= hsize) {
+ qcs->flags |= QC_SF_BLK_MROOM;
+ goto end;
+ }
- b_putchr(&outbuf, 0x00); /* h3 frame type = DATA */
- b_quic_enc_int(&outbuf, fsize);
+ if (b_size(&outbuf) < hsize + fsize)
+ fsize = b_size(&outbuf) - hsize;
+ BUG_ON(fsize <= 0);
- total += fsize;
+ b_putchr(&outbuf, 0x00); /* h3 frame type = DATA */
+ b_quic_enc_int(&outbuf, fsize); /* h3 frame length */
+
b_putblk(&outbuf, htx_get_blk_ptr(htx, blk), fsize);
+ total += fsize;
count -= fsize;
if (fsize == bsize)
@@ -577,6 +591,7 @@
else
htx_cut_data_blk(htx, blk, fsize);
+ /* commit the buffer */
b_add(res, b_data(&outbuf));
goto new_frame;
@@ -597,7 +612,7 @@
htx = htx_from_buf(buf);
- while (count && !htx_is_empty(htx)) {
+ while (count && !htx_is_empty(htx) && !(qcs->flags & QC_SF_BLK_MROOM)) {
idx = htx_get_head(htx);
blk = htx_get_blk(htx, idx);
btype = htx_get_blk_type(blk);
@@ -643,10 +658,13 @@
if ((htx->flags & HTX_FL_EOM) && htx_is_empty(htx))
qcs->flags |= QC_SF_FIN_STREAM;
- // TODO should I call the mux directly here ?
- qc_snd_buf(cs, buf, total, flags);
out:
+ if (total) {
+ if (!(qcs->qcc->wait_event.events & SUB_RETRY_SEND))
+ tasklet_wakeup(qcs->qcc->wait_event.tasklet);
+ }
+
return total;
}
diff --git a/src/mux_quic.c b/src/mux_quic.c
index 710aa0e..55a4dc5 100644
--- a/src/mux_quic.c
+++ b/src/mux_quic.c
@@ -1350,7 +1350,7 @@
static int qc_send(struct qcc *qcc)
{
struct eb64_node *node;
- int ret, done;
+ int ret, done, xprt_wake = 0;
TRACE_ENTER(QC_EV_QCC_SEND, qcc->conn);
ret = done = 0;
@@ -1380,18 +1380,26 @@
if (ret < 0)
ABORT_NOW();
+ if (ret > 0) {
+ xprt_wake = 1;
+ if (qcs->flags & QC_SF_BLK_MROOM) {
+ qcs->flags &= ~QC_SF_BLK_MROOM;
+ qcs_notify_send(qcs);
+ }
+ }
+
qcs->tx.offset += ret;
+
if (b_data(buf)) {
qcc->conn->xprt->subscribe(qcc->conn, qcc->conn->xprt_ctx,
SUB_RETRY_SEND, &qcc->wait_event);
- break;
}
}
node = eb64_next(node);
}
- if (ret > 0)
- tasklet_wakeup(((struct ssl_sock_ctx *)(qcc->conn->xprt_ctx))->wait_event.tasklet);
+ if (xprt_wake)
+ tasklet_wakeup(((struct ssl_sock_ctx *)(qcc->conn->xprt_ctx))->wait_event.tasklet);
TRACE_LEAVE(QC_EV_QCC_SEND, qcc->conn);
return 0;
@@ -1836,25 +1844,6 @@
/* Called from the upper layer, to send data from buffer <buf> for no more than
* <count> bytes. Returns the number of bytes effectively sent. Some status
- * flags may be updated on the conn_stream.
- */
-size_t qc_snd_buf(struct conn_stream *cs, struct buffer *buf, size_t count, int flags)
-{
- struct qcs *qcs = cs->ctx;
-
- TRACE_ENTER(QC_EV_QCS_SEND|QC_EV_STRM_SEND, qcs->qcc->conn, qcs);
-
- if (count) {
- if (!(qcs->qcc->wait_event.events & SUB_RETRY_SEND))
- tasklet_wakeup(qcs->qcc->wait_event.tasklet);
- }
-
- TRACE_LEAVE(QC_EV_QCS_SEND|QC_EV_STRM_SEND, qcs->qcc->conn, qcs);
- return count;
-}
-
-/* Called from the upper layer, to send data from buffer <buf> for no more than
- * <count> bytes. Returns the number of bytes effectively sent. Some status
* flags may be updated on the mux.
*/
size_t luqs_snd_buf(struct qcs *qcs, struct buffer *buf, size_t count, int flags)