MINOR: quic: Speeding up Handshake Completion

According to RFC 9002 par. 6.2.3. when receving duplicate Initial CRYPTO
data a server may a packet containing non unacknowledged before the PTO
expiry.

diff --git a/src/xprt_quic.c b/src/xprt_quic.c
index 630f8d16d5d482090879b1a6b6e5f1b7a49dd4a9..5d9b82e25f6c9323a6dd21acea38817ecdcbe802 100644 (file)
--- a/src/xprt_quic.c
+++ b/src/xprt_quic.c
@@ -2170,6 +2170,34 @@ static inline int qc_handle_strm_frm(struct quic_rx_packet *pkt,
                return qc_handle_bidi_strm_frm(pkt, strm_frm, qc);
 }
 
+/* Prepare a fast retransmission from <qel> encryption level
+ * which must be Initial encryption level.
+ */
+static void qc_prep_fast_retrans(struct quic_enc_level *qel,
+                                 struct quic_conn *qc)
+{
+       struct eb_root *pkts = &qel->pktns->tx.pkts;
+       struct eb64_node *node = eb64_first(pkts);
+       struct quic_tx_packet *pkt;
+       struct quic_frame *frm, *frmbak;
+
+ start:
+       pkts = &qel->pktns->tx.pkts;
+       node = eb64_first(pkts);
+       if (!node)
+               return;
+
+       pkt = eb64_entry(&node->node, struct quic_tx_packet, pn_node);
+       list_for_each_entry_safe(frm, frmbak, &pkt->frms, list)
+               qc_treat_nacked_tx_frm(qc, frm, qel->pktns);
+       if (qel == &qc->els[QUIC_TLS_ENC_LEVEL_INITIAL] &&
+           qc->els[QUIC_TLS_ENC_LEVEL_HANDSHAKE].pktns->tx.in_flight) {
+               qc->els[QUIC_TLS_ENC_LEVEL_HANDSHAKE].pktns->tx.pto_probe = 1;
+               qel = &qc->els[QUIC_TLS_ENC_LEVEL_HANDSHAKE];
+               goto start;
+       }
+}
+
 /* Parse all the frames of <pkt> QUIC packet for QUIC connection with <ctx>
  * as I/O handler context and <qel> as encryption level.
  * Returns 1 if succeeded, 0 if failed.
@@ -2180,6 +2208,7 @@ static int qc_parse_pkt_frms(struct quic_rx_packet *pkt, struct ssl_sock_ctx *ct
        struct quic_frame frm;
        const unsigned char *pos, *end;
        struct quic_conn *qc = ctx->qc;
+       int fast_retrans = 0;
 
        TRACE_ENTER(QUIC_EV_CONN_PRSHPKT, qc);
        /* Skip the AAD */
@@ -2231,6 +2260,9 @@ static int qc_parse_pkt_frms(struct quic_rx_packet *pkt, struct ssl_sock_ctx *ct
                                        /* Nothing to do */
                                        TRACE_PROTO("Already received CRYPTO data",
                                                    QUIC_EV_CONN_ELRXPKTS, qc, pkt, &cfdebug);
+                                       if (objt_listener(ctx->conn->target) &&
+                                           qel == &qc->els[QUIC_TLS_ENC_LEVEL_INITIAL])
+                                               fast_retrans = 1;
                                        break;
                                }
                                else {
@@ -2321,6 +2353,12 @@ static int qc_parse_pkt_frms(struct quic_rx_packet *pkt, struct ssl_sock_ctx *ct
                }
        }
 
+       if (fast_retrans) {
+               qc_prep_fast_retrans(qel, qc);
+               if (qc->els[QUIC_TLS_ENC_LEVEL_HANDSHAKE].pktns->tx.in_flight)
+                       qc_prep_fast_retrans(&qc->els[QUIC_TLS_ENC_LEVEL_HANDSHAKE], qc);
+       }
+
        /* The server must switch from INITIAL to HANDSHAKE handshake state when it
         * has successfully parse a Handshake packet. The Initial encryption must also
         * be discarded.