Release 2.27.6

- [BUGFIX] Replace dispatch read/write events assertion with a check.
- [BUGFIX] gQUIC connection close: there is no HEADERS stream without
  HTTP flag, see issue #220.
- http_client, http_server: add hq protocol support and other flags
  for use with QUIC Interop Runner.
- Fix: use IP_PMTUDISC_PROBE (not IP_PMTUDISC_DO) on Linux to set
  Don't-Fragment flag on outgoing packets.
- Fix send_packets_one_by_one on Windows platform when sending
  multiple iovs, see issue #218.
- Exit echo_client on Windows immediately, see issue #219.

src/liblsquic/lsquic_full_conn.c

@@ -2615,10 +2615,12 @@ maybe_close_conn (struct full_conn *conn)
     struct lsquic_stream *stream;
     struct lsquic_hash_elem *el;
 #endif
+    const unsigned n_special_streams = N_SPECIAL_STREAMS
+                                     - !(conn->fc_flags & FC_HTTP);
 
     if ((conn->fc_flags & (FC_CLOSING|FC_GOAWAY_SENT|FC_SERVER))
                                             == (FC_GOAWAY_SENT|FC_SERVER)
-        && lsquic_hash_count(conn->fc_pub.all_streams) == N_SPECIAL_STREAMS)
+        && lsquic_hash_count(conn->fc_pub.all_streams) == n_special_streams)
     {
 #ifndef NDEBUG
         for (el = lsquic_hash_first(conn->fc_pub.all_streams); el;

src/liblsquic/lsquic_parse_ietf_v1.c

@@ -1699,6 +1699,22 @@ static const enum header_type bits2ht[4] =
 };
 
 
+#if LSQUIC_QIR
+/* Return true if the parsing function is to enforce the minimum DCID
+ * length requirement as specified in IETF v1 and the I-Ds.
+ */
+static int
+enforce_initial_dcil (lsquic_ver_tag_t tag)
+{
+    enum lsquic_version version;
+
+    version = lsquic_tag2ver(tag);
+    return version != (enum lsquic_version) -1
+        && ((1 << version) & LSQUIC_IETF_VERSIONS);
+}
+#endif
+
+
 int
 lsquic_ietf_v1_parse_packet_in_long_begin (struct lsquic_packet_in *packet_in,
                 size_t length, int is_server, unsigned cid_len,
@@ -1751,6 +1767,14 @@ lsquic_ietf_v1_parse_packet_in_long_begin (struct lsquic_packet_in *packet_in,
     switch (header_type)
     {
     case HETY_INITIAL:
+#if LSQUIC_QIR
+        if (!enforce_initial_dcil(tag))
+        {
+            /* Count even zero-length DCID as having DCID */
+            packet_in->pi_flags |= PI_CONN_ID;
+        }
+        else
+#endif
         if (is_server && dcil < MIN_INITIAL_DCID_LEN)
             return -1;
         r = vint_read(p, end, &token_len);

src/liblsquic/lsquic_stream.c

@@ -2363,12 +2363,13 @@ maybe_mark_as_blocked (lsquic_stream_t *stream)
 void
 lsquic_stream_dispatch_read_events (lsquic_stream_t *stream)
 {
-    assert(stream->sm_qflags & SMQF_WANT_READ);
-
-    if (stream->sm_bflags & SMBF_RW_ONCE)
-        stream_dispatch_read_events_once(stream);
-    else
-        stream_dispatch_read_events_loop(stream);
+    if (stream->sm_qflags & SMQF_WANT_READ)
+    {
+        if (stream->sm_bflags & SMBF_RW_ONCE)
+            stream_dispatch_read_events_once(stream);
+        else
+            stream_dispatch_read_events_loop(stream);
+    }
 }
 
 
@@ -2381,7 +2382,9 @@ lsquic_stream_dispatch_write_events (lsquic_stream_t *stream)
     unsigned short n_buffered;
     enum stream_q_flags q_flags;
 
-    assert(stream->sm_qflags & SMQF_WRITE_Q_FLAGS);
+    if (!(stream->sm_qflags & SMQF_WRITE_Q_FLAGS))
+        return;
+
     q_flags = stream->sm_qflags & SMQF_WRITE_Q_FLAGS;
     tosend_off = stream->tosend_off;
     n_buffered = stream->sm_n_buffered;