deps: update ngtcp2 to 1.2.0

nodejs-github-bot · targos · commit 8f63f6ff5761 · 2024-02-15T12:05:54.000+01:00
PR-URL: #51584 Reviewed-By: Marco Ippolito <marcoippolito54@gmail.com> Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
diff --git a/deps/ngtcp2/ngtcp2/lib/includes/ngtcp2/ngtcp2.h b/deps/ngtcp2/ngtcp2/lib/includes/ngtcp2/ngtcp2.h
@@ -4269,6 +4269,9 @@ NGTCP2_EXTERN int ngtcp2_conn_open_uni_stream(ngtcp2_conn *conn,
  *
  * |flags| is currently unused, and should be set to 0.
  *
+ * This function returns 0 if a stream denoted by |stream_id| is not
+ * found.
+ *
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
@@ -4291,6 +4294,9 @@ NGTCP2_EXTERN int ngtcp2_conn_shutdown_stream(ngtcp2_conn *conn, uint32_t flags,
  *
  * |flags| is currently unused, and should be set to 0.
  *
+ * This function returns 0 if a stream denoted by |stream_id| is not
+ * found.
+ *
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
@@ -4315,6 +4321,9 @@ NGTCP2_EXTERN int ngtcp2_conn_shutdown_stream_write(ngtcp2_conn *conn,
  *
  * |flags| is currently unused, and should be set to 0.
  *
+ * This function returns 0 if a stream denoted by |stream_id| is not
+ * found.
+ *
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
@@ -4675,6 +4684,9 @@ NGTCP2_EXTERN int ngtcp2_conn_in_draining_period(ngtcp2_conn *conn);
  * specifies the stream ID.  This function only extends stream-level
  * flow control window.
  *
+ * This function returns 0 if a stream denoted by |stream_id| is not
+ * found.
+ *
  * This function returns 0 if it succeeds, or one of the following
  * negative error codes:
  *
@@ -5340,6 +5352,11 @@ NGTCP2_EXTERN void ngtcp2_ccerr_set_application_error(ngtcp2_ccerr *ccerr,
  * CONNECTION_CLOSE (type 0x1d) frame.  Otherwise, it does not produce
  * any data, and returns 0.
  *
+ * |destlen| could be shorten by some factors (e.g., server side
+ * amplification limit).  This function returns
+ * :macro:`NGTCP2_ERR_NOBUF` if the resulting buffer is too small even
+ * if the given buffer has enough space.
+ *
  * This function must not be called from inside the callback
  * functions.
  *
diff --git a/deps/ngtcp2/ngtcp2/lib/includes/ngtcp2/version.h b/deps/ngtcp2/ngtcp2/lib/includes/ngtcp2/version.h
@@ -36,7 +36,7 @@
  *
  * Version number of the ngtcp2 library release.
  */
-#define NGTCP2_VERSION "1.1.0"
+#define NGTCP2_VERSION "1.2.0"
 
 /**
  * @macro
@@ -46,6 +46,6 @@
  * number, 8 bits for minor and 8 bits for patch. Version 1.2.3
  * becomes 0x010203.
  */
-#define NGTCP2_VERSION_NUM 0x010100
+#define NGTCP2_VERSION_NUM 0x010200
 
 #endif /* VERSION_H */
diff --git a/deps/ngtcp2/ngtcp2/lib/ngtcp2_cc.c b/deps/ngtcp2/ngtcp2/lib/ngtcp2_cc.c
@@ -36,6 +36,7 @@
 #include "ngtcp2_mem.h"
 #include "ngtcp2_rcvry.h"
 #include "ngtcp2_conn_stat.h"
+#include "ngtcp2_unreachable.h"
 
 /* NGTCP2_CC_DELIVERY_RATE_SEC_FILTERLEN is the window length of
    delivery rate filter driven by ACK clocking. */
@@ -247,6 +248,8 @@ uint64_t ngtcp2_cbrt(uint64_t n) {
 #  if defined(_WIN64)
     if (_BitScanReverse64(&index, n)) {
       d = 61 - index;
+    } else {
+      ngtcp2_unreachable();
     }
 #  else  /* !defined(_WIN64) */
     if (_BitScanReverse(&index, (unsigned int)(n >> 32))) {
diff --git a/deps/ngtcp2/ngtcp2/lib/ngtcp2_conn.c b/deps/ngtcp2/ngtcp2/lib/ngtcp2_conn.c
@@ -5329,7 +5329,6 @@ static int conn_recv_ack(ngtcp2_conn *conn, ngtcp2_pktns *pktns, ngtcp2_ack *fr,
   num_acked = ngtcp2_rtb_recv_ack(&pktns->rtb, fr, &conn->cstat, conn, pktns,
                                   pkt_ts, ts);
   if (num_acked < 0) {
-    /* TODO assert this */
     assert(ngtcp2_err_is_fatal((int)num_acked));
     return (int)num_acked;
   }
@@ -5790,9 +5789,8 @@ static int conn_recv_path_response(ngtcp2_conn *conn, ngtcp2_path_response *fr,
   }
 
   if (!(pv->flags & NGTCP2_PV_FLAG_DONT_CARE)) {
-    if (!(pv->flags & NGTCP2_PV_FLAG_FALLBACK_ON_FAILURE)) {
+    if (pv->dcid.seq != conn->dcid.current.seq) {
       assert(!conn->server);
-      assert(pv->dcid.seq != conn->dcid.current.seq);
       assert(conn->dcid.current.cid.datalen);
 
       rv = conn_retire_dcid(conn, &conn->dcid.current, ts);
@@ -5871,25 +5869,6 @@ static int conn_recv_path_response(ngtcp2_conn *conn, ngtcp2_path_response *fr,
   return conn_stop_pv(conn, ts);
 }
 
-/*
- * pkt_num_bits returns the number of bits available when packet
- * number is encoded in |pkt_numlen| bytes.
- */
-static size_t pkt_num_bits(size_t pkt_numlen) {
-  switch (pkt_numlen) {
-  case 1:
-    return 8;
-  case 2:
-    return 16;
-  case 3:
-    return 24;
-  case 4:
-    return 32;
-  default:
-    ngtcp2_unreachable();
-  }
-}
-
 /*
  * pktns_pkt_num_is_duplicate returns nonzero if |pkt_num| is
  * duplicated packet number.
@@ -6020,9 +5999,7 @@ static int conn_verify_fixed_bit(ngtcp2_conn *conn, ngtcp2_pkt_hd *hd) {
     case NGTCP2_PKT_INITIAL:
     case NGTCP2_PKT_0RTT:
     case NGTCP2_PKT_HANDSHAKE:
-      /* TODO we cannot determine whether a token comes from NEW_TOKEN
-         frame or Retry packet.  RFC 9287 requires that a token from
-         NEW_TOKEN. */
+      /* RFC 9287 requires that a token from NEW_TOKEN. */
       if (!(conn->flags & NGTCP2_CONN_FLAG_INITIAL_PKT_PROCESSED) &&
           (conn->local.settings.token_type != NGTCP2_TOKEN_TYPE_NEW_TOKEN ||
            !conn->local.settings.tokenlen)) {
@@ -6145,7 +6122,8 @@ conn_recv_handshake_pkt(ngtcp2_conn *conn, const ngtcp2_path *path,
     return NGTCP2_ERR_DISCARD_PKT;
   }
 
-  if (hd.type == NGTCP2_PKT_VERSION_NEGOTIATION) {
+  switch (hd.type) {
+  case NGTCP2_PKT_VERSION_NEGOTIATION:
     hdpktlen = (size_t)nread;
 
     ngtcp2_log_rx_pkt_hd(&conn->log, &hd);
@@ -6181,7 +6159,7 @@ conn_recv_handshake_pkt(ngtcp2_conn *conn, const ngtcp2_path *path,
       return NGTCP2_ERR_DISCARD_PKT;
     }
     return NGTCP2_ERR_RECV_VERSION_NEGOTIATION;
-  } else if (hd.type == NGTCP2_PKT_RETRY) {
+  case NGTCP2_PKT_RETRY:
     hdpktlen = (size_t)nread;
 
     ngtcp2_log_rx_pkt_hd(&conn->log, &hd);
@@ -6402,10 +6380,7 @@ conn_recv_handshake_pkt(ngtcp2_conn *conn, const ngtcp2_path *path,
 
     break;
   default:
-    /* unknown packet type */
-    ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT,
-                    "packet was ignored because of unknown packet type");
-    return (ngtcp2_ssize)pktlen;
+    ngtcp2_unreachable();
   }
 
   hp_mask = conn->callbacks.hp_mask;
@@ -6438,7 +6413,7 @@ conn_recv_handshake_pkt(ngtcp2_conn *conn, const ngtcp2_path *path,
   payloadlen = hd.len - hd.pkt_numlen;
 
   hd.pkt_num = ngtcp2_pkt_adjust_pkt_num(pktns->rx.max_pkt_num, hd.pkt_num,
-                                         pkt_num_bits(hd.pkt_numlen));
+                                         hd.pkt_numlen);
   if (hd.pkt_num > NGTCP2_MAX_PKT_NUM) {
     ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT,
                     "pkn=%" PRId64 " is greater than maximum pkn", hd.pkt_num);
@@ -6624,14 +6599,8 @@ conn_recv_handshake_pkt(ngtcp2_conn *conn, const ngtcp2_path *path,
 
   pktns_increase_ecn_counts(pktns, pi);
 
-  /* TODO Initial and Handshake are always acknowledged without
-     delay. */
-  if (require_ack &&
-      (++pktns->acktr.rx_npkt >= conn->local.settings.ack_thresh ||
-       (pi->ecn & NGTCP2_ECN_MASK) == NGTCP2_ECN_CE)) {
-    ngtcp2_acktr_immediate_ack(&pktns->acktr);
-  }
-
+  /* Initial and Handshake are always acknowledged without delay.  No
+     need to call ngtcp2_acktr_immediate_ack(). */
   rv = ngtcp2_conn_sched_ack(conn, &pktns->acktr, hd.pkt_num, require_ack,
                              pkt_ts);
   if (rv != 0) {
@@ -7057,7 +7026,7 @@ static int conn_recv_stream(ngtcp2_conn *conn, const ngtcp2_stream *fr) {
     if (strm == NULL) {
       return NGTCP2_ERR_NOMEM;
     }
-    /* TODO Perhaps, call new_stream callback? */
+
     rv = ngtcp2_conn_init_stream(conn, strm, fr->stream_id, NULL);
     if (rv != 0) {
       ngtcp2_objalloc_strm_release(&conn->strm_objalloc, strm);
@@ -7464,7 +7433,7 @@ static int conn_recv_stop_sending(ngtcp2_conn *conn,
       return 0;
     }
 
-    /* Frame is received reset before we create ngtcp2_strm
+    /* STOP_SENDING frame is received before we create ngtcp2_strm
        object. */
     strm = ngtcp2_objalloc_strm_get(&conn->strm_objalloc);
     if (strm == NULL) {
@@ -7482,6 +7451,10 @@ static int conn_recv_stop_sending(ngtcp2_conn *conn,
     }
   }
 
+  if (strm->flags & NGTCP2_STRM_FLAG_STOP_SENDING_RECVED) {
+    return 0;
+  }
+
   ngtcp2_strm_set_app_error_code(strm, fr->app_error_code);
 
   /* No RESET_STREAM is required if we have sent FIN and all data have
@@ -7494,7 +7467,9 @@ static int conn_recv_stop_sending(ngtcp2_conn *conn,
     }
   }
 
-  strm->flags |= NGTCP2_STRM_FLAG_SHUT_WR | NGTCP2_STRM_FLAG_RESET_STREAM;
+  strm->flags |= NGTCP2_STRM_FLAG_SHUT_WR |
+                 NGTCP2_STRM_FLAG_STOP_SENDING_RECVED |
+                 NGTCP2_STRM_FLAG_RESET_STREAM;
 
   ngtcp2_strm_streamfrq_clear(strm);
 
@@ -8751,12 +8726,8 @@ conn_recv_delayed_handshake_pkt(ngtcp2_conn *conn, const ngtcp2_pkt_info *pi,
 
   pktns_increase_ecn_counts(pktns, pi);
 
-  if (require_ack &&
-      (++pktns->acktr.rx_npkt >= conn->local.settings.ack_thresh ||
-       (pi->ecn & NGTCP2_ECN_MASK) == NGTCP2_ECN_CE)) {
-    ngtcp2_acktr_immediate_ack(&pktns->acktr);
-  }
-
+  /* Initial and Handshake are always acknowledged without delay.  No
+     need to call ngtcp2_acktr_immediate_ack(). */
   rv = ngtcp2_conn_sched_ack(conn, &pktns->acktr, hd->pkt_num, require_ack,
                              pkt_ts);
   if (rv != 0) {
@@ -9020,7 +8991,7 @@ static ngtcp2_ssize conn_recv_pkt(ngtcp2_conn *conn, const ngtcp2_path *path,
   payloadlen = pktlen - hdpktlen;
 
   hd.pkt_num = ngtcp2_pkt_adjust_pkt_num(pktns->rx.max_pkt_num, hd.pkt_num,
-                                         pkt_num_bits(hd.pkt_numlen));
+                                         hd.pkt_numlen);
   if (hd.pkt_num > NGTCP2_MAX_PKT_NUM) {
     ngtcp2_log_info(&conn->log, NGTCP2_LOG_EVENT_PKT,
                     "pkn=%" PRId64 " is greater than maximum pkn", hd.pkt_num);
@@ -12551,7 +12522,8 @@ static int conn_shutdown_stream_read(ngtcp2_conn *conn, ngtcp2_strm *strm,
                                      uint64_t app_error_code) {
   ngtcp2_strm_set_app_error_code(strm, app_error_code);
 
-  if (strm->flags & NGTCP2_STRM_FLAG_STOP_SENDING) {
+  if (strm->flags &
+      (NGTCP2_STRM_FLAG_STOP_SENDING | NGTCP2_STRM_FLAG_RESET_STREAM_RECVED)) {
     return 0;
   }
   if ((strm->flags & NGTCP2_STRM_FLAG_SHUT_RD) &&
diff --git a/deps/ngtcp2/ngtcp2/lib/ngtcp2_log.c b/deps/ngtcp2/ngtcp2/lib/ngtcp2_log.c
@@ -68,8 +68,7 @@ void ngtcp2_log_init(ngtcp2_log *log, const ngtcp2_cid *scid,
  *   Source Connection ID in hex string.
  *
  * <EVENT>:
- *   Event.  pkt=packet, frm=frame, ldc=loss-detection, cry=crypto,
- *   con=connection(catch all)
+ *   Event.  See ngtcp2_log_event.
  *
  * # Frame event
  *
diff --git a/deps/ngtcp2/ngtcp2/lib/ngtcp2_net.h b/deps/ngtcp2/ngtcp2/lib/ngtcp2_net.h
@@ -87,7 +87,7 @@
 #if defined(WIN32)
 /* Windows requires ws2_32 library for ntonl family functions.  We
    define inline functions for those function so that we don't have
-   dependeny on that lib. */
+   dependency on that lib. */
 
 #  ifdef _MSC_VER
 #    define STIN static __inline
diff --git a/deps/ngtcp2/ngtcp2/lib/ngtcp2_pkt.c b/deps/ngtcp2/ngtcp2/lib/ngtcp2_pkt.c
@@ -558,7 +558,7 @@ ngtcp2_ssize ngtcp2_pkt_decode_stream_frame(ngtcp2_stream *dest,
   uint8_t type;
   size_t len = 1 + 1;
   const uint8_t *p;
-  size_t datalen;
+  size_t datalen = 0;
   size_t ndatalen = 0;
   size_t n;
   uint64_t vi;
@@ -2139,9 +2139,9 @@ int ngtcp2_pkt_decode_retry(ngtcp2_pkt_retry *dest, const uint8_t *payload,
 }
 
 int64_t ngtcp2_pkt_adjust_pkt_num(int64_t max_pkt_num, int64_t pkt_num,
-                                  size_t n) {
+                                  size_t pkt_numlen) {
   int64_t expected = max_pkt_num + 1;
-  int64_t win = (int64_t)1 << n;
+  int64_t win = (int64_t)1 << (pkt_numlen * 8);
   int64_t hwin = win / 2;
   int64_t mask = win - 1;
   int64_t cand = (expected & ~mask) | pkt_num;
diff --git a/deps/ngtcp2/ngtcp2/lib/ngtcp2_pkt.h b/deps/ngtcp2/ngtcp2/lib/ngtcp2_pkt.h
@@ -1120,12 +1120,12 @@ ngtcp2_ssize ngtcp2_pkt_encode_datagram_frame(uint8_t *out, size_t outlen,
 
 /*
  * ngtcp2_pkt_adjust_pkt_num find the full 64 bits packet number for
- * |pkt_num|, which is expected to be least significant |n| bits.  The
+ * |pkt_num|, which is encoded in |pkt_numlen| bytes.  The
  * |max_pkt_num| is the highest successfully authenticated packet
  * number.
  */
 int64_t ngtcp2_pkt_adjust_pkt_num(int64_t max_pkt_num, int64_t pkt_num,
-                                  size_t n);
+                                  size_t pkt_numlen);
 
 /*
  * ngtcp2_pkt_validate_ack checks that ack is malformed or not.
diff --git a/deps/ngtcp2/ngtcp2/lib/ngtcp2_ppe.c b/deps/ngtcp2/ngtcp2/lib/ngtcp2_ppe.c
@@ -39,7 +39,6 @@ void ngtcp2_ppe_init(ngtcp2_ppe *ppe, uint8_t *out, size_t outlen,
   ppe->pkt_num_offset = 0;
   ppe->pkt_numlen = 0;
   ppe->pkt_num = 0;
-  ppe->sample_offset = 0;
   ppe->cc = cc;
 }
 
@@ -69,8 +68,6 @@ int ngtcp2_ppe_encode_hd(ngtcp2_ppe *ppe, const ngtcp2_pkt_hd *hd) {
     return (int)rv;
   }
 
-  ppe->sample_offset = ppe->pkt_num_offset + 4;
-
   buf->last += rv;
 
   ppe->pkt_numlen = hd->pkt_numlen;
@@ -101,6 +98,14 @@ int ngtcp2_ppe_encode_frame(ngtcp2_ppe *ppe, ngtcp2_frame *fr) {
   return 0;
 }
 
+/*
+ * ppe_sample_offset returns the offset to sample for packet number
+ * encryption.
+ */
+static size_t ppe_sample_offset(ngtcp2_ppe *ppe) {
+  return ppe->pkt_num_offset + 4;
+}
+
 ngtcp2_ssize ngtcp2_ppe_final(ngtcp2_ppe *ppe, const uint8_t **ppkt) {
   ngtcp2_buf *buf = &ppe->buf;
   ngtcp2_crypto_cc *cc = ppe->cc;
@@ -132,9 +137,10 @@ ngtcp2_ssize ngtcp2_ppe_final(ngtcp2_ppe *ppe, const uint8_t **ppkt) {
   buf->last = payload + payloadlen + cc->aead.max_overhead;
 
   /* TODO Check that we have enough space to get sample */
-  assert(ppe->sample_offset + NGTCP2_HP_SAMPLELEN <= ngtcp2_buf_len(buf));
+  assert(ppe_sample_offset(ppe) + NGTCP2_HP_SAMPLELEN <= ngtcp2_buf_len(buf));
 
-  rv = cc->hp_mask(mask, &cc->hp, &cc->hp_ctx, buf->begin + ppe->sample_offset);
+  rv = cc->hp_mask(mask, &cc->hp, &cc->hp_ctx,
+                   buf->begin + ppe_sample_offset(ppe));
   if (rv != 0) {
     return NGTCP2_ERR_CALLBACK_FAILURE;
   }
@@ -197,7 +203,7 @@ size_t ngtcp2_ppe_padding_hp_sample(ngtcp2_ppe *ppe) {
   assert(cc->aead.max_overhead);
 
   max_samplelen =
-      ngtcp2_buf_len(buf) + cc->aead.max_overhead - ppe->sample_offset;
+      ngtcp2_buf_len(buf) + cc->aead.max_overhead - ppe_sample_offset(ppe);
   if (max_samplelen < NGTCP2_HP_SAMPLELEN) {
     len = NGTCP2_HP_SAMPLELEN - max_samplelen;
     assert(ngtcp2_ppe_left(ppe) >= len);
diff --git a/deps/ngtcp2/ngtcp2/lib/ngtcp2_ppe.h b/deps/ngtcp2/ngtcp2/lib/ngtcp2_ppe.h
@@ -50,9 +50,6 @@ typedef struct ngtcp2_ppe {
   /* pkt_numlen is the number of bytes used to encode a packet
      number */
   size_t pkt_numlen;
-  /* sample_offset is the offset to sample for packet number
-     encryption. */
-  size_t sample_offset;
   /* pkt_num is the packet number written in buf. */
   int64_t pkt_num;
   /* nonce is the buffer to store nonce.  It should be equal or longer
diff --git a/deps/ngtcp2/ngtcp2/lib/ngtcp2_pq.h b/deps/ngtcp2/ngtcp2/lib/ngtcp2_pq.h
diff --git a/deps/ngtcp2/ngtcp2/lib/ngtcp2_rtb.c b/deps/ngtcp2/ngtcp2/lib/ngtcp2_rtb.c
diff --git a/deps/ngtcp2/ngtcp2/lib/ngtcp2_strm.h b/deps/ngtcp2/ngtcp2/lib/ngtcp2_strm.h
diff --git a/deps/ngtcp2/ngtcp2/lib/ngtcp2_window_filter.c b/deps/ngtcp2/ngtcp2/lib/ngtcp2_window_filter.c

Original file line number	Diff line number	Diff line change
`@@ -4269,6 +4269,9 @@ NGTCP2_EXTERN int ngtcp2_conn_open_uni_stream(ngtcp2_conn *conn,`
`4269`	`4269`	`*`
`4270`	`4270`	`* \|flags\| is currently unused, and should be set to 0.`
`4271`	`4271`	`*`
	`4272`	`+ * This function returns 0 if a stream denoted by \|stream_id\| is not`
	`4273`	`+ * found.`
	`4274`	`+ *`
`4272`	`4275`	`* This function returns 0 if it succeeds, or one of the following`
`4273`	`4276`	`* negative error codes:`
`4274`	`4277`	`*`
`@@ -4291,6 +4294,9 @@ NGTCP2_EXTERN int ngtcp2_conn_shutdown_stream(ngtcp2_conn *conn, uint32_t flags,`
`4291`	`4294`	`*`
`4292`	`4295`	`* \|flags\| is currently unused, and should be set to 0.`
`4293`	`4296`	`*`
	`4297`	`+ * This function returns 0 if a stream denoted by \|stream_id\| is not`
	`4298`	`+ * found.`
	`4299`	`+ *`
`4294`	`4300`	`* This function returns 0 if it succeeds, or one of the following`
`4295`	`4301`	`* negative error codes:`
`4296`	`4302`	`*`
`@@ -4315,6 +4321,9 @@ NGTCP2_EXTERN int ngtcp2_conn_shutdown_stream_write(ngtcp2_conn *conn,`
`4315`	`4321`	`*`
`4316`	`4322`	`* \|flags\| is currently unused, and should be set to 0.`
`4317`	`4323`	`*`
	`4324`	`+ * This function returns 0 if a stream denoted by \|stream_id\| is not`
	`4325`	`+ * found.`
	`4326`	`+ *`
`4318`	`4327`	`* This function returns 0 if it succeeds, or one of the following`
`4319`	`4328`	`* negative error codes:`
`4320`	`4329`	`*`
`@@ -4675,6 +4684,9 @@ NGTCP2_EXTERN int ngtcp2_conn_in_draining_period(ngtcp2_conn *conn);`
`4675`	`4684`	`* specifies the stream ID. This function only extends stream-level`
`4676`	`4685`	`* flow control window.`
`4677`	`4686`	`*`
	`4687`	`+ * This function returns 0 if a stream denoted by \|stream_id\| is not`
	`4688`	`+ * found.`
	`4689`	`+ *`
`4678`	`4690`	`* This function returns 0 if it succeeds, or one of the following`
`4679`	`4691`	`* negative error codes:`
`4680`	`4692`	`*`
`@@ -5340,6 +5352,11 @@ NGTCP2_EXTERN void ngtcp2_ccerr_set_application_error(ngtcp2_ccerr *ccerr,`
`5340`	`5352`	`* CONNECTION_CLOSE (type 0x1d) frame. Otherwise, it does not produce`
`5341`	`5353`	`* any data, and returns 0.`
`5342`	`5354`	`*`
	`5355`	`+ * \|destlen\| could be shorten by some factors (e.g., server side`
	`5356`	`+ * amplification limit). This function returns`
	`5357`	+ * :macro:`NGTCP2_ERR_NOBUF` if the resulting buffer is too small even
	`5358`	`+ * if the given buffer has enough space.`
	`5359`	`+ *`
`5343`	`5360`	`* This function must not be called from inside the callback`
`5344`	`5361`	`* functions.`
`5345`	`5362`	`*`