OPTIM: quic: do not call qc_prep_pkts() if everything sent

qc_send() is implemented as a loop to repeatedly invoke
qc_prep_pkts()/qc_send_ppkts(). This ensures that all data are emitted
even if bigger that a single Tx buffer instance. This is useful if
congestion window is empty but big enough for application data.

Looping is interrupted if qc_prep_pkts() returns a negative error
code, for example due to no space left in congestion window. It can also
returns 0 if no input data to sent, which also interrupt the loop.

To limit this last case, removed quic_enc_level from send_list each time
everything already send via qc_prep_pkts(). Loop can then be interrupted
as soon as send_list is empty, avoiding an extra superfluous call to
qc_prep_pkts().

diff --git a/src/quic_tx.c b/src/quic_tx.c
index 99f2a59cafa669085c33df1d0e14a93a290a0f70..ba81a7713356f8841b616646153785136d412c26 100644 (file)
--- a/src/quic_tx.c
+++ b/src/quic_tx.c
@@ -491,7 +491,7 @@ static int qc_prep_pkts(struct quic_conn *qc, struct buffer *buf,
        unsigned char *end, *pos;
        uint16_t dglen;
        size_t total;
-       struct quic_enc_level *qel;
+       struct quic_enc_level *qel, *tmp_qel;
 
        TRACE_ENTER(QUIC_EV_CONN_IO_CB, qc);
        /* Currently qc_prep_pkts() does not handle buffer wrapping so the
@@ -507,7 +507,7 @@ static int qc_prep_pkts(struct quic_conn *qc, struct buffer *buf,
        dglen = 0;
        total = 0;
 
-       list_for_each_entry(qel, qels, el_send) {
+       list_for_each_entry_safe(qel, tmp_qel, qels, el_send) {
                struct quic_tls_ctx *tls_ctx;
                const struct quic_version *ver;
                struct list *frms = qel->send_frms, *next_frms;
@@ -547,6 +547,10 @@ static int qc_prep_pkts(struct quic_conn *qc, struct buffer *buf,
                                probe = qel->pktns->tx.pto_probe;
 
                        if (!qc_may_build_pkt(qc, frms, qel, cc, probe, &must_ack)) {
+                               /* Remove qel from send_list if nothing to send. */
+                               LIST_DEL_INIT(&qel->el_send);
+                               qel->send_frms = NULL;
+
                                if (prv_pkt && !next_qel) {
                                        qc_txb_store(buf, dglen, first_pkt);
                                        /* Build only one datagram when an immediate close is required. */
@@ -650,7 +654,6 @@ static int qc_prep_pkts(struct quic_conn *qc, struct buffer *buf,
                                        padding = 1;
 
                                prv_pkt = cur_pkt;
-                               break;
                        }
                        else {
                                qc_txb_store(buf, dglen, first_pkt);
@@ -724,7 +727,7 @@ int qc_send(struct quic_conn *qc, int old_data, struct list *send_list)
                                qc_txb_release(qc);
                        goto out;
                }
-       } while (ret > 0);
+       } while (ret > 0 && !LIST_ISEMPTY(send_list));
 
        qc_txb_release(qc);
        if (ret < 0)