BUG/MINOR: quic: Do not probe with too little Initial packets

Before probing the Initial packet number space, verify that we can at least
sent 1200 bytes by datagram. This may not be the case due to the amplification limit.

Must be backported to 2.6 and 2.7.

diff --git a/src/quic_conn.c b/src/quic_conn.c
index f2b5c84..5124243 100644 (file)
--- a/src/quic_conn.c
+++ b/src/quic_conn.c
@@ -4759,6 +4759,16 @@ static int quic_conn_enc_level_init(struct quic_conn *qc,
        return ret;
 }
 
+/* Return 1 if <qc> connection may probe the Initial packet number space, 0 if not.
+ * This is not the case if the remote peer address is not validated and if
+ * it cannot send at least QUIC_INITIAL_PACKET_MINLEN bytes.
+ */
+static int qc_may_probe_ipktns(struct quic_conn *qc)
+{
+       return quic_peer_validated_addr(qc) ||
+              (int)(3 * qc->rx.bytes - qc->tx.prep_bytes) >= QUIC_INITIAL_PACKET_MINLEN;
+}
+
 /* Callback called upon loss detection and PTO timer expirations. */
 struct task *qc_process_timer(struct task *task, void *ctx, unsigned int state)
 {
@@ -4790,24 +4800,39 @@ struct task *qc_process_timer(struct task *task, void *ctx, unsigned int state)
                                qc->subs = NULL;
                }
                else {
-                       qc->flags |= QUIC_FL_CONN_RETRANS_NEEDED;
-                       pktns->flags |= QUIC_FL_PKTNS_PROBE_NEEDED;
                        if (pktns == &qc->pktns[QUIC_TLS_PKTNS_INITIAL]) {
-                               TRACE_STATE("needs to probe Initial packet number space", QUIC_EV_CONN_TXPKT, qc);
+                               if (qc_may_probe_ipktns(qc)) {
+                                       qc->flags |= QUIC_FL_CONN_RETRANS_NEEDED;
+                                       pktns->flags |= QUIC_FL_PKTNS_PROBE_NEEDED;
+                                       TRACE_STATE("needs to probe Initial packet number space", QUIC_EV_CONN_TXPKT, qc);
+                               }
+                               else {
+                                       TRACE_STATE("Cannot probe Initial packet number space", QUIC_EV_CONN_TXPKT, qc);
+                               }
                                if (qc->pktns[QUIC_TLS_PKTNS_HANDSHAKE].tx.in_flight) {
+                                       qc->flags |= QUIC_FL_CONN_RETRANS_NEEDED;
                                        qc->pktns[QUIC_TLS_PKTNS_HANDSHAKE].flags |= QUIC_FL_PKTNS_PROBE_NEEDED;
                                        TRACE_STATE("needs to probe Handshake packet number space", QUIC_EV_CONN_TXPKT, qc);
                                }
                        }
                        else if (pktns == &qc->pktns[QUIC_TLS_PKTNS_HANDSHAKE]) {
                                TRACE_STATE("needs to probe Handshake packet number space", QUIC_EV_CONN_TXPKT, qc);
+                               qc->flags |= QUIC_FL_CONN_RETRANS_NEEDED;
+                               pktns->flags |= QUIC_FL_PKTNS_PROBE_NEEDED;
                                if (qc->pktns[QUIC_TLS_PKTNS_INITIAL].tx.in_flight) {
-                                       qc->pktns[QUIC_TLS_PKTNS_INITIAL].flags |= QUIC_FL_PKTNS_PROBE_NEEDED;
-                                       TRACE_STATE("needs to probe Initial packet number space", QUIC_EV_CONN_TXPKT, qc);
+                                       if (qc_may_probe_ipktns(qc)) {
+                                               qc->pktns[QUIC_TLS_PKTNS_INITIAL].flags |= QUIC_FL_PKTNS_PROBE_NEEDED;
+                                               TRACE_STATE("needs to probe Initial packet number space", QUIC_EV_CONN_TXPKT, qc);
+                                       }
+                                       else {
+                                               TRACE_STATE("Cannot probe Initial packet number space", QUIC_EV_CONN_TXPKT, qc);
+                                       }
                                }
                        }
                        else if (pktns == &qc->pktns[QUIC_TLS_PKTNS_01RTT]) {
                                TRACE_STATE("needs to probe 01RTT packet number space", QUIC_EV_CONN_TXPKT, qc);
+                               qc->flags |= QUIC_FL_CONN_RETRANS_NEEDED;
+                               pktns->flags |= QUIC_FL_PKTNS_PROBE_NEEDED;
                        }
                }
        }