MINOR: h3: support DATA demux if buffer full

Previously, h3 layer was not able to demux a DATA frame if not fully
received in the Rx buffer. This causes evident limitation and prevents
to be able to demux a frame bigger than the buffer.

Improve h3_data_to_htx() to support partial frame demuxing. The demux
state is preserved in the h3s new fields : this is useful to keep the
current type and length of the demuxed frame.

diff --git a/src/h3.c b/src/h3.c
index 2a46c1e148f349a381cd2b681599ba899a3d9be3..f5da7613aeef36bd9bd62a734590f392bfe53cd6 100644 (file)
--- a/src/h3.c
+++ b/src/h3.c
@@ -69,6 +69,8 @@ struct h3 {
 DECLARE_STATIC_POOL(pool_head_h3, "h3", sizeof(struct h3));
 
 struct h3s {
+       int demux_frame_len;
+       int demux_frame_type;
 };
 
 DECLARE_STATIC_POOL(pool_head_h3s, "h3s", sizeof(struct h3s));
@@ -213,10 +215,20 @@ static int h3_data_to_htx(struct qcs *qcs, struct buffer *buf, uint64_t len,
        BUG_ON(!appbuf);
        htx = htx_from_buf(appbuf);
 
+       if (len > b_data(buf)) {
+               len = b_data(buf);
+               fin = 0;
+       }
+
+       head = b_head(buf);
  retry:
        htx_space = htx_free_data_space(htx);
-       if (!htx_space || htx_space < len) {
-               ABORT_NOW(); /* TODO handle this case properly */
+       if (!htx_space)
+               goto out;
+
+       if (len > htx_space) {
+               len = htx_space;
+               fin = 0;
        }
 
        contig = b_contig_data(buf, contig);
@@ -230,10 +242,11 @@ static int h3_data_to_htx(struct qcs *qcs, struct buffer *buf, uint64_t len,
        htx_sent += htx_add_data(htx, ist2(head, len));
        BUG_ON(htx_sent < len);
 
-       if (fin)
+       if (fin && len == htx_sent)
                htx->flags |= HTX_FL_EOM;
-       htx_to_buf(htx, appbuf);
 
+ out:
+       htx_to_buf(htx, appbuf);
        return htx_sent;
 }
 
@@ -244,6 +257,7 @@ static int h3_data_to_htx(struct qcs *qcs, struct buffer *buf, uint64_t len,
 static int h3_decode_qcs(struct qcs *qcs, int fin, void *ctx)
 {
        struct buffer *rxbuf = &qcs->rx.buf;
+       struct h3s *h3s = qcs->ctx;
        ssize_t ret;
 
        h3_debug_printf(stderr, "%s: STREAM ID: %lu\n", __func__, qcs->id);
@@ -251,26 +265,29 @@ static int h3_decode_qcs(struct qcs *qcs, int fin, void *ctx)
                return 0;
 
        while (b_data(rxbuf)) {
-               size_t hlen;
                uint64_t ftype, flen;
                struct buffer b;
                char last_stream_frame = 0;
 
                /* Work on a copy of <rxbuf> */
                b = h3_b_dup(rxbuf);
-               hlen = h3_decode_frm_header(&ftype, &flen, &b);
-               if (!hlen)
-                       break;
+               if (!h3s->demux_frame_len) {
+                       size_t hlen = h3_decode_frm_header(&ftype, &flen, &b);
+                       if (!hlen)
+                               break;
 
-               h3_debug_printf(stderr, "%s: ftype: %llu, flen: %llu\n", __func__,
-                       (unsigned long long)ftype, (unsigned long long)flen);
-               if (flen > b_data(&b) && !b_full(rxbuf))
-                       break;
+                       h3_debug_printf(stderr, "%s: ftype: %lu, flen: %lu\n",
+                                       __func__, ftype, flen);
 
-               /* TODO handle full rxbuf */
-               BUG_ON(flen > b_size(rxbuf));
+                       b_del(rxbuf, hlen);
+                       h3s->demux_frame_type = ftype;
+                       h3s->demux_frame_len = flen;
+               }
 
-               b_del(rxbuf, hlen);
+               flen = h3s->demux_frame_len;
+               ftype = h3s->demux_frame_type;
+               if (flen > b_data(&b) && !b_full(rxbuf))
+                       break;
                last_stream_frame = (fin && flen == b_data(rxbuf));
 
                switch (ftype) {
@@ -300,6 +317,8 @@ static int h3_decode_qcs(struct qcs *qcs, int fin, void *ctx)
                        break;
 
                b_del(rxbuf, ret);
+               BUG_ON(h3s->demux_frame_len < ret);
+               h3s->demux_frame_len -= ret;
        }
 
        return 0;
@@ -734,6 +753,9 @@ static int h3_attach(struct qcs *qcs)
                return 1;
 
        qcs->ctx = h3s;
+       h3s->demux_frame_len = 0;
+       h3s->demux_frame_type = 0;
+
        return 0;
 }