quickjs-tart

http2.c (96767B)

---

 /***************************************************************************
  *                                  _   _ ____  _
  *  Project                     ___| | | |  _ \| |
  *                             / __| | | | |_) | |
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
  * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
  * are also available at https://curl.se/docs/copyright.html.
  *
  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
  * copies of the Software, and permit persons to whom the Software is
  * furnished to do so, under the terms of the COPYING file.
  *
  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  * KIND, either express or implied.
  *
  * SPDX-License-Identifier: curl
  *
  ***************************************************************************/
 
 #include "curl_setup.h"
 
 #ifdef USE_NGHTTP2
 #include <stdint.h>
 #include <nghttp2/nghttp2.h>
 #include "urldata.h"
 #include "bufq.h"
 #include "uint-hash.h"
 #include "http1.h"
 #include "http2.h"
 #include "http.h"
 #include "sendf.h"
 #include "select.h"
 #include "curlx/base64.h"
 #include "multiif.h"
 #include "url.h"
 #include "urlapi-int.h"
 #include "cfilters.h"
 #include "connect.h"
 #include "rand.h"
 #include "strdup.h"
 #include "curlx/strparse.h"
 #include "transfer.h"
 #include "curlx/dynbuf.h"
 #include "headers.h"
 /* The last 3 #include files should be in this order */
 #include "curl_printf.h"
 #include "curl_memory.h"
 #include "memdebug.h"
 
 #if (NGHTTP2_VERSION_NUM < 0x010c00)
 #error too old nghttp2 version, upgrade!
 #endif
 
 #ifdef CURL_DISABLE_VERBOSE_STRINGS
 #define nghttp2_session_callbacks_set_error_callback(x,y)
 #endif
 
 #if (NGHTTP2_VERSION_NUM >= 0x010c00)
 #define NGHTTP2_HAS_SET_LOCAL_WINDOW_SIZE 1
 #endif
 
 
 /* buffer dimensioning:
  * use 16K as chunk size, as that fits H2 DATA frames well */
 #define H2_CHUNK_SIZE           (16 * 1024)
 /* connection window size */
 #define H2_CONN_WINDOW_SIZE     (10 * 1024 * 1024)
 /* on receiving from TLS, we prep for holding a full stream window */
 #define H2_NW_RECV_CHUNKS       (H2_CONN_WINDOW_SIZE / H2_CHUNK_SIZE)
 /* on send into TLS, we just want to accumulate small frames */
 #define H2_NW_SEND_CHUNKS       1
 /* this is how much we want "in flight" for a stream, unthrottled  */
 #define H2_STREAM_WINDOW_SIZE_MAX   (10 * 1024 * 1024)
 /* this is how much we want "in flight" for a stream, initially, IFF
  * nghttp2 allows us to tweak the local window size. */
 #if NGHTTP2_HAS_SET_LOCAL_WINDOW_SIZE
 #define H2_STREAM_WINDOW_SIZE_INITIAL  (64 * 1024)
 #else
 #define H2_STREAM_WINDOW_SIZE_INITIAL H2_STREAM_WINDOW_SIZE_MAX
 #endif
 /* keep smaller stream upload buffer (default h2 window size) to have
  * our progress bars and "upload done" reporting closer to reality */
 #define H2_STREAM_SEND_CHUNKS   ((64 * 1024) / H2_CHUNK_SIZE)
 /* spare chunks we keep for a full window */
 #define H2_STREAM_POOL_SPARES   (H2_CONN_WINDOW_SIZE / H2_CHUNK_SIZE)
 
 /* We need to accommodate the max number of streams with their window sizes on
  * the overall connection. Streams might become PAUSED which will block their
  * received QUOTA in the connection window. If we run out of space, the server
  * is blocked from sending us any data. See #10988 for an issue with this. */
 #define HTTP2_HUGE_WINDOW_SIZE (100 * H2_STREAM_WINDOW_SIZE_MAX)
 
 #define H2_SETTINGS_IV_LEN  3
 #define H2_BINSETTINGS_LEN 80
 
 static size_t populate_settings(nghttp2_settings_entry *iv,
                                 struct Curl_easy *data)
 {
   iv[0].settings_id = NGHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS;
   iv[0].value = Curl_multi_max_concurrent_streams(data->multi);
 
   iv[1].settings_id = NGHTTP2_SETTINGS_INITIAL_WINDOW_SIZE;
   iv[1].value = H2_STREAM_WINDOW_SIZE_INITIAL;
 
   iv[2].settings_id = NGHTTP2_SETTINGS_ENABLE_PUSH;
   iv[2].value = data->multi->push_cb != NULL;
 
   return 3;
 }
 
 static ssize_t populate_binsettings(uint8_t *binsettings,
                                     struct Curl_easy *data)
 {
   nghttp2_settings_entry iv[H2_SETTINGS_IV_LEN];
   size_t ivlen;
 
   ivlen = populate_settings(iv, data);
   /* this returns number of bytes it wrote or a negative number on error. */
   return nghttp2_pack_settings_payload(binsettings, H2_BINSETTINGS_LEN,
                                        iv, ivlen);
 }
 
 struct cf_h2_ctx {
   nghttp2_session *h2;
   /* The easy handle used in the current filter call, cleared at return */
   struct cf_call_data call_data;
 
   struct bufq inbufq;           /* network input */
   struct bufq outbufq;          /* network output */
   struct bufc_pool stream_bufcp; /* spares for stream buffers */
   struct dynbuf scratch;        /* scratch buffer for temp use */
 
   struct uint_hash streams; /* hash of `data->mid` to `h2_stream_ctx` */
   size_t drain_total; /* sum of all stream's UrlState drain */
   uint32_t max_concurrent_streams;
   uint32_t goaway_error;        /* goaway error code from server */
   int32_t remote_max_sid;       /* max id processed by server */
   int32_t local_max_sid;        /* max id processed by us */
 #ifdef DEBUGBUILD
   int32_t stream_win_max;       /* max h2 stream window size */
 #endif
   BIT(initialized);
   BIT(via_h1_upgrade);
   BIT(conn_closed);
   BIT(rcvd_goaway);
   BIT(sent_goaway);
   BIT(enable_push);
   BIT(nw_out_blocked);
 };
 
 /* How to access `call_data` from a cf_h2 filter */
 #undef CF_CTX_CALL_DATA
 #define CF_CTX_CALL_DATA(cf)  \
   ((struct cf_h2_ctx *)(cf)->ctx)->call_data
 
 static void h2_stream_hash_free(unsigned int id, void *stream);
 
 static void cf_h2_ctx_init(struct cf_h2_ctx *ctx, bool via_h1_upgrade)
 {
   Curl_bufcp_init(&ctx->stream_bufcp, H2_CHUNK_SIZE, H2_STREAM_POOL_SPARES);
   Curl_bufq_initp(&ctx->inbufq, &ctx->stream_bufcp, H2_NW_RECV_CHUNKS, 0);
   Curl_bufq_initp(&ctx->outbufq, &ctx->stream_bufcp, H2_NW_SEND_CHUNKS, 0);
   curlx_dyn_init(&ctx->scratch, CURL_MAX_HTTP_HEADER);
   Curl_uint_hash_init(&ctx->streams, 63, h2_stream_hash_free);
   ctx->remote_max_sid = 2147483647;
   ctx->via_h1_upgrade = via_h1_upgrade;
 #ifdef DEBUGBUILD
   {
     const char *p = getenv("CURL_H2_STREAM_WIN_MAX");
 
     ctx->stream_win_max = H2_STREAM_WINDOW_SIZE_MAX;
     if(p) {
       curl_off_t l;
       if(!curlx_str_number(&p, &l, INT_MAX))
         ctx->stream_win_max = (int32_t)l;
     }
   }
 #endif
   ctx->initialized = TRUE;
 }
 
 static void cf_h2_ctx_free(struct cf_h2_ctx *ctx)
 {
   if(ctx && ctx->initialized) {
     Curl_bufq_free(&ctx->inbufq);
     Curl_bufq_free(&ctx->outbufq);
     Curl_bufcp_free(&ctx->stream_bufcp);
     curlx_dyn_free(&ctx->scratch);
     Curl_uint_hash_destroy(&ctx->streams);
     memset(ctx, 0, sizeof(*ctx));
   }
   free(ctx);
 }
 
 static void cf_h2_ctx_close(struct cf_h2_ctx *ctx)
 {
   if(ctx->h2) {
     nghttp2_session_del(ctx->h2);
   }
 }
 
 static CURLcode nw_out_flush(struct Curl_cfilter *cf,
                              struct Curl_easy *data);
 
 static CURLcode h2_progress_egress(struct Curl_cfilter *cf,
                                    struct Curl_easy *data);
 
 /**
  * All about the H2 internals of a stream
  */
 struct h2_stream_ctx {
   struct bufq sendbuf; /* request buffer */
   struct h1_req_parser h1; /* parsing the request */
   struct dynhds resp_trailers; /* response trailer fields */
   size_t resp_hds_len; /* amount of response header bytes in recvbuf */
   curl_off_t nrcvd_data;  /* number of DATA bytes received */
 
   char **push_headers;       /* allocated array */
   size_t push_headers_used;  /* number of entries filled in */
   size_t push_headers_alloc; /* number of entries allocated */
 
   int status_code; /* HTTP response status code */
   uint32_t error; /* stream error code */
   CURLcode xfer_result; /* Result of writing out response */
   int32_t local_window_size; /* the local recv window size */
   int32_t id; /* HTTP/2 protocol identifier for stream */
   BIT(resp_hds_complete); /* we have a complete, final response */
   BIT(closed); /* TRUE on stream close */
   BIT(reset);  /* TRUE on stream reset */
   BIT(close_handled); /* TRUE if stream closure is handled by libcurl */
   BIT(bodystarted);
   BIT(body_eos);    /* the complete body has been added to `sendbuf` and
                      * is being/has been processed from there. */
   BIT(write_paused);  /* stream write is paused */
 };
 
 #define H2_STREAM_CTX(ctx,data)                                         \
   ((struct h2_stream_ctx *)(                                            \
     data? Curl_uint_hash_get(&(ctx)->streams, (data)->mid) : NULL))
 
 static struct h2_stream_ctx *h2_stream_ctx_create(struct cf_h2_ctx *ctx)
 {
   struct h2_stream_ctx *stream;
 
   (void)ctx;
   stream = calloc(1, sizeof(*stream));
   if(!stream)
     return NULL;
 
   stream->id = -1;
   Curl_bufq_initp(&stream->sendbuf, &ctx->stream_bufcp,
                   H2_STREAM_SEND_CHUNKS, BUFQ_OPT_NONE);
   Curl_h1_req_parse_init(&stream->h1, H1_PARSE_DEFAULT_MAX_LINE_LEN);
   Curl_dynhds_init(&stream->resp_trailers, 0, DYN_HTTP_REQUEST);
   stream->bodystarted = FALSE;
   stream->status_code = -1;
   stream->closed = FALSE;
   stream->close_handled = FALSE;
   stream->error = NGHTTP2_NO_ERROR;
   stream->local_window_size = H2_STREAM_WINDOW_SIZE_INITIAL;
   stream->nrcvd_data = 0;
   return stream;
 }
 
 static void free_push_headers(struct h2_stream_ctx *stream)
 {
   size_t i;
   for(i = 0; i < stream->push_headers_used; i++)
     free(stream->push_headers[i]);
   Curl_safefree(stream->push_headers);
   stream->push_headers_used = 0;
 }
 
 static void h2_stream_ctx_free(struct h2_stream_ctx *stream)
 {
   Curl_bufq_free(&stream->sendbuf);
   Curl_h1_req_parse_free(&stream->h1);
   Curl_dynhds_free(&stream->resp_trailers);
   free_push_headers(stream);
   free(stream);
 }
 
 static void h2_stream_hash_free(unsigned int id, void *stream)
 {
   (void)id;
   DEBUGASSERT(stream);
   h2_stream_ctx_free((struct h2_stream_ctx *)stream);
 }
 
 #ifdef NGHTTP2_HAS_SET_LOCAL_WINDOW_SIZE
 static int32_t cf_h2_get_desired_local_win(struct Curl_cfilter *cf,
                                            struct Curl_easy *data)
 {
   (void)cf;
   if(data->set.max_recv_speed && data->set.max_recv_speed < INT32_MAX) {
     /* The transfer should only receive `max_recv_speed` bytes per second.
      * We restrict the stream's local window size, so that the server cannot
      * send us "too much" at a time.
      * This gets less precise the higher the latency. */
     return (int32_t)data->set.max_recv_speed;
   }
 #ifdef DEBUGBUILD
   else {
     struct cf_h2_ctx *ctx = cf->ctx;
     CURL_TRC_CF(data, cf, "stream_win_max=%d", ctx->stream_win_max);
     return ctx->stream_win_max;
   }
 #else
   return H2_STREAM_WINDOW_SIZE_MAX;
 #endif
 }
 
 static CURLcode cf_h2_update_local_win(struct Curl_cfilter *cf,
                                        struct Curl_easy *data,
                                        struct h2_stream_ctx *stream)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   int32_t dwsize;
   int rv;
 
   dwsize = (stream->write_paused || stream->xfer_result) ?
            0 : cf_h2_get_desired_local_win(cf, data);
   if(dwsize != stream->local_window_size) {
     int32_t wsize = nghttp2_session_get_stream_effective_local_window_size(
                       ctx->h2, stream->id);
     if(dwsize > wsize) {
       rv = nghttp2_session_set_local_window_size(ctx->h2, NGHTTP2_FLAG_NONE,
                                                  stream->id, dwsize);
       if(rv) {
         failf(data, "[%d] nghttp2 set_local_window_size(%d) failed: "
               "%s(%d)", stream->id, dwsize, nghttp2_strerror(rv), rv);
         return CURLE_HTTP2;
       }
       rv = nghttp2_submit_window_update(ctx->h2, NGHTTP2_FLAG_NONE,
                                         stream->id, dwsize - wsize);
       if(rv) {
         failf(data, "[%d] nghttp2_submit_window_update() failed: "
               "%s(%d)", stream->id, nghttp2_strerror(rv), rv);
         return CURLE_HTTP2;
       }
       stream->local_window_size = dwsize;
       CURL_TRC_CF(data, cf, "[%d] local window update by %d",
                   stream->id, dwsize - wsize);
     }
     else {
       rv = nghttp2_session_set_local_window_size(ctx->h2, NGHTTP2_FLAG_NONE,
                                                  stream->id, dwsize);
       if(rv) {
         failf(data, "[%d] nghttp2_session_set_local_window_size() failed: "
               "%s(%d)", stream->id, nghttp2_strerror(rv), rv);
         return CURLE_HTTP2;
       }
       stream->local_window_size = dwsize;
       CURL_TRC_CF(data, cf, "[%d] local window size now %d",
                   stream->id, dwsize);
     }
   }
   return CURLE_OK;
 }
 
 #else /* NGHTTP2_HAS_SET_LOCAL_WINDOW_SIZE */
 
 static CURLcode cf_h2_update_local_win(struct Curl_cfilter *cf,
                                        struct Curl_easy *data,
                                        struct h2_stream_ctx *stream)
 {
   (void)cf;
   (void)data;
   (void)stream;
   return CURLE_OK;
 }
 #endif /* !NGHTTP2_HAS_SET_LOCAL_WINDOW_SIZE */
 
 
 static CURLcode http2_data_setup(struct Curl_cfilter *cf,
                                  struct Curl_easy *data,
                                  struct h2_stream_ctx **pstream)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   struct h2_stream_ctx *stream;
 
   (void)cf;
   DEBUGASSERT(data);
   stream = H2_STREAM_CTX(ctx, data);
   if(stream) {
     *pstream = stream;
     return CURLE_OK;
   }
 
   stream = h2_stream_ctx_create(ctx);
   if(!stream)
     return CURLE_OUT_OF_MEMORY;
 
   if(!Curl_uint_hash_set(&ctx->streams, data->mid, stream)) {
     h2_stream_ctx_free(stream);
     return CURLE_OUT_OF_MEMORY;
   }
 
   *pstream = stream;
   return CURLE_OK;
 }
 
 static void http2_data_done(struct Curl_cfilter *cf, struct Curl_easy *data)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   struct h2_stream_ctx *stream = H2_STREAM_CTX(ctx, data);
 
   DEBUGASSERT(ctx);
   if(!stream || !ctx->initialized)
     return;
 
   if(ctx->h2) {
     bool flush_egress = FALSE;
     /* returns error if stream not known, which is fine here */
     (void)nghttp2_session_set_stream_user_data(ctx->h2, stream->id, NULL);
 
     if(!stream->closed && stream->id > 0) {
       /* RST_STREAM */
       CURL_TRC_CF(data, cf, "[%d] premature DATA_DONE, RST stream",
                   stream->id);
       stream->closed = TRUE;
       stream->reset = TRUE;
       nghttp2_submit_rst_stream(ctx->h2, NGHTTP2_FLAG_NONE,
                                 stream->id, NGHTTP2_STREAM_CLOSED);
       flush_egress = TRUE;
     }
 
     if(flush_egress) {
       (void)nghttp2_session_send(ctx->h2);
       (void)nw_out_flush(cf, data);
     }
   }
 
   Curl_uint_hash_remove(&ctx->streams, data->mid);
 }
 
 static int h2_client_new(struct Curl_cfilter *cf,
                          nghttp2_session_callbacks *cbs)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   nghttp2_option *o;
   nghttp2_mem mem = {NULL, Curl_nghttp2_malloc, Curl_nghttp2_free,
     Curl_nghttp2_calloc, Curl_nghttp2_realloc};
 
   int rc = nghttp2_option_new(&o);
   if(rc)
     return rc;
   /* We handle window updates ourself to enforce buffer limits */
   nghttp2_option_set_no_auto_window_update(o, 1);
 #if NGHTTP2_VERSION_NUM >= 0x013200
   /* with 1.50.0 */
   /* turn off RFC 9113 leading and trailing white spaces validation against
      HTTP field value. */
   nghttp2_option_set_no_rfc9113_leading_and_trailing_ws_validation(o, 1);
 #endif
   rc = nghttp2_session_client_new3(&ctx->h2, cbs, cf, o, &mem);
   nghttp2_option_del(o);
   return rc;
 }
 
 static ssize_t send_callback(nghttp2_session *h2,
                              const uint8_t *mem, size_t length, int flags,
                              void *userp);
 static int on_frame_recv(nghttp2_session *session, const nghttp2_frame *frame,
                          void *userp);
 static int cf_h2_on_invalid_frame_recv(nghttp2_session *session,
                                        const nghttp2_frame *frame,
                                        int lib_error_code,
                                        void *user_data);
 #ifndef CURL_DISABLE_VERBOSE_STRINGS
 static int on_frame_send(nghttp2_session *session, const nghttp2_frame *frame,
                          void *userp);
 #endif
 static int on_data_chunk_recv(nghttp2_session *session, uint8_t flags,
                               int32_t stream_id,
                               const uint8_t *mem, size_t len, void *userp);
 static int on_stream_close(nghttp2_session *session, int32_t stream_id,
                            uint32_t error_code, void *userp);
 static int on_begin_headers(nghttp2_session *session,
                             const nghttp2_frame *frame, void *userp);
 static int on_header(nghttp2_session *session, const nghttp2_frame *frame,
                      const uint8_t *name, size_t namelen,
                      const uint8_t *value, size_t valuelen,
                      uint8_t flags,
                      void *userp);
 #if !defined(CURL_DISABLE_VERBOSE_STRINGS)
 static int error_callback(nghttp2_session *session, const char *msg,
                           size_t len, void *userp);
 #endif
 static CURLcode cf_h2_ctx_open(struct Curl_cfilter *cf,
                                struct Curl_easy *data)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   struct h2_stream_ctx *stream;
   CURLcode result = CURLE_OUT_OF_MEMORY;
   int rc;
   nghttp2_session_callbacks *cbs = NULL;
 
   DEBUGASSERT(!ctx->h2);
   DEBUGASSERT(ctx->initialized);
 
   rc = nghttp2_session_callbacks_new(&cbs);
   if(rc) {
     failf(data, "Couldn't initialize nghttp2 callbacks");
     goto out;
   }
 
   nghttp2_session_callbacks_set_send_callback(cbs, send_callback);
   nghttp2_session_callbacks_set_on_frame_recv_callback(cbs, on_frame_recv);
   nghttp2_session_callbacks_set_on_invalid_frame_recv_callback(cbs,
     cf_h2_on_invalid_frame_recv);
 #ifndef CURL_DISABLE_VERBOSE_STRINGS
   nghttp2_session_callbacks_set_on_frame_send_callback(cbs, on_frame_send);
 #endif
   nghttp2_session_callbacks_set_on_data_chunk_recv_callback(
     cbs, on_data_chunk_recv);
   nghttp2_session_callbacks_set_on_stream_close_callback(cbs, on_stream_close);
   nghttp2_session_callbacks_set_on_begin_headers_callback(
     cbs, on_begin_headers);
   nghttp2_session_callbacks_set_on_header_callback(cbs, on_header);
 #if !defined(CURL_DISABLE_VERBOSE_STRINGS)
   nghttp2_session_callbacks_set_error_callback(cbs, error_callback);
 #endif
 
   /* The nghttp2 session is not yet setup, do it */
   rc = h2_client_new(cf, cbs);
   if(rc) {
     failf(data, "Couldn't initialize nghttp2");
     goto out;
   }
   ctx->max_concurrent_streams = DEFAULT_MAX_CONCURRENT_STREAMS;
 
   if(ctx->via_h1_upgrade) {
     /* HTTP/1.1 Upgrade issued. H2 Settings have already been submitted
      * in the H1 request and we upgrade from there. This stream
      * is opened implicitly as #1. */
     uint8_t binsettings[H2_BINSETTINGS_LEN];
     ssize_t binlen; /* length of the binsettings data */
 
     binlen = populate_binsettings(binsettings, data);
     if(binlen <= 0) {
       failf(data, "nghttp2 unexpectedly failed on pack_settings_payload");
       result = CURLE_FAILED_INIT;
       goto out;
     }
 
     result = http2_data_setup(cf, data, &stream);
     if(result)
       goto out;
     DEBUGASSERT(stream);
     stream->id = 1;
     /* queue SETTINGS frame (again) */
     rc = nghttp2_session_upgrade2(ctx->h2, binsettings, (size_t)binlen,
                                   data->state.httpreq == HTTPREQ_HEAD,
                                   NULL);
     if(rc) {
       failf(data, "nghttp2_session_upgrade2() failed: %s(%d)",
             nghttp2_strerror(rc), rc);
       result = CURLE_HTTP2;
       goto out;
     }
 
     rc = nghttp2_session_set_stream_user_data(ctx->h2, stream->id,
                                               data);
     if(rc) {
       infof(data, "http/2: failed to set user_data for stream %u",
             stream->id);
       DEBUGASSERT(0);
     }
     CURL_TRC_CF(data, cf, "created session via Upgrade");
   }
   else {
     nghttp2_settings_entry iv[H2_SETTINGS_IV_LEN];
     size_t ivlen;
 
     ivlen = populate_settings(iv, data);
     rc = nghttp2_submit_settings(ctx->h2, NGHTTP2_FLAG_NONE,
                                  iv, ivlen);
     if(rc) {
       failf(data, "nghttp2_submit_settings() failed: %s(%d)",
             nghttp2_strerror(rc), rc);
       result = CURLE_HTTP2;
       goto out;
     }
   }
 
   rc = nghttp2_session_set_local_window_size(ctx->h2, NGHTTP2_FLAG_NONE, 0,
                                              HTTP2_HUGE_WINDOW_SIZE);
   if(rc) {
     failf(data, "nghttp2_session_set_local_window_size() failed: %s(%d)",
           nghttp2_strerror(rc), rc);
     result = CURLE_HTTP2;
     goto out;
   }
 
   /* all set, traffic will be send on connect */
   result = CURLE_OK;
   CURL_TRC_CF(data, cf, "[0] created h2 session%s",
               ctx->via_h1_upgrade ? " (via h1 upgrade)" : "");
 
 out:
   if(cbs)
     nghttp2_session_callbacks_del(cbs);
   return result;
 }
 
 /*
  * Returns nonzero if current HTTP/2 session should be closed.
  */
 static int should_close_session(struct cf_h2_ctx *ctx)
 {
   return ctx->drain_total == 0 && !nghttp2_session_want_read(ctx->h2) &&
     !nghttp2_session_want_write(ctx->h2);
 }
 
 /*
  * Processes pending input left in network input buffer.
  * This function returns 0 if it succeeds, or -1 and error code will
  * be assigned to *err.
  */
 static int h2_process_pending_input(struct Curl_cfilter *cf,
                                     struct Curl_easy *data,
                                     CURLcode *err)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   const unsigned char *buf;
   size_t blen;
   ssize_t rv;
 
   while(Curl_bufq_peek(&ctx->inbufq, &buf, &blen)) {
 
     rv = nghttp2_session_mem_recv(ctx->h2, (const uint8_t *)buf, blen);
     if(rv < 0) {
       failf(data, "nghttp2 recv error %zd: %s", rv, nghttp2_strerror((int)rv));
       *err = CURLE_HTTP2;
       return -1;
     }
     Curl_bufq_skip(&ctx->inbufq, (size_t)rv);
     if(Curl_bufq_is_empty(&ctx->inbufq)) {
       break;
     }
     else {
       CURL_TRC_CF(data, cf, "process_pending_input: %zu bytes left "
                   "in connection buffer", Curl_bufq_len(&ctx->inbufq));
     }
   }
 
   if(nghttp2_session_check_request_allowed(ctx->h2) == 0) {
     /* No more requests are allowed in the current session, so
        the connection may not be reused. This is set when a
        GOAWAY frame has been received or when the limit of stream
        identifiers has been reached. */
     connclose(cf->conn, "http/2: No new requests allowed");
   }
 
   return 0;
 }
 
 /*
  * The server may send us data at any point (e.g. PING frames). Therefore,
  * we cannot assume that an HTTP/2 socket is dead just because it is readable.
  *
  * Check the lower filters first and, if successful, peek at the socket
  * and distinguish between closed and data.
  */
 static bool http2_connisalive(struct Curl_cfilter *cf, struct Curl_easy *data,
                               bool *input_pending)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   bool alive = TRUE;
 
   *input_pending = FALSE;
   if(!cf->next || !cf->next->cft->is_alive(cf->next, data, input_pending))
     return FALSE;
 
   if(*input_pending) {
     /* This happens before we have sent off a request and the connection is
        not in use by any other transfer, there should not be any data here,
        only "protocol frames" */
     CURLcode result;
     size_t nread;
 
     *input_pending = FALSE;
     result = Curl_cf_recv_bufq(cf->next, data, &ctx->inbufq, 0, &nread);
     if(!result) {
       CURL_TRC_CF(data, cf, "%zu bytes stray data read before trying "
                   "h2 connection", nread);
       if(h2_process_pending_input(cf, data, &result) < 0)
         /* immediate error, considered dead */
         alive = FALSE;
       else {
         alive = !should_close_session(ctx);
       }
     }
     else if(result != CURLE_AGAIN) {
       /* the read failed so let's say this is dead anyway */
       alive = FALSE;
     }
   }
 
   return alive;
 }
 
 static CURLcode http2_send_ping(struct Curl_cfilter *cf,
                                 struct Curl_easy *data)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   int rc;
 
   rc = nghttp2_submit_ping(ctx->h2, 0, ZERO_NULL);
   if(rc) {
     failf(data, "nghttp2_submit_ping() failed: %s(%d)",
           nghttp2_strerror(rc), rc);
    return CURLE_HTTP2;
   }
 
   rc = nghttp2_session_send(ctx->h2);
   if(rc) {
     failf(data, "nghttp2_session_send() failed: %s(%d)",
           nghttp2_strerror(rc), rc);
     return CURLE_SEND_ERROR;
   }
   return CURLE_OK;
 }
 
 /*
  * Store nghttp2 version info in this buffer.
  */
 void Curl_http2_ver(char *p, size_t len)
 {
   nghttp2_info *h2 = nghttp2_version(0);
   (void)msnprintf(p, len, "nghttp2/%s", h2->version_str);
 }
 
 static CURLcode nw_out_flush(struct Curl_cfilter *cf,
                              struct Curl_easy *data)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   size_t nwritten;
   CURLcode result;
 
   (void)data;
   if(Curl_bufq_is_empty(&ctx->outbufq))
     return CURLE_OK;
 
   result = Curl_cf_send_bufq(cf->next, data, &ctx->outbufq, NULL, 0,
                              &nwritten);
   if(result) {
     if(result == CURLE_AGAIN) {
       CURL_TRC_CF(data, cf, "flush nw send buffer(%zu) -> EAGAIN",
                   Curl_bufq_len(&ctx->outbufq));
       ctx->nw_out_blocked = 1;
     }
     return result;
   }
   return Curl_bufq_is_empty(&ctx->outbufq) ? CURLE_OK : CURLE_AGAIN;
 }
 
 /*
  * The implementation of nghttp2_send_callback type. Here we write |data| with
  * size |length| to the network and return the number of bytes actually
  * written. See the documentation of nghttp2_send_callback for the details.
  */
 static ssize_t send_callback(nghttp2_session *h2,
                              const uint8_t *buf, size_t blen, int flags,
                              void *userp)
 {
   struct Curl_cfilter *cf = userp;
   struct cf_h2_ctx *ctx = cf->ctx;
   struct Curl_easy *data = CF_DATA_CURRENT(cf);
   size_t nwritten;
   CURLcode result = CURLE_OK;
 
   (void)h2;
   (void)flags;
   DEBUGASSERT(data);
 
   if(!cf->connected)
     result = Curl_bufq_write(&ctx->outbufq, buf, blen, &nwritten);
   else
     result = Curl_cf_send_bufq(cf->next, data, &ctx->outbufq, buf, blen,
                                &nwritten);
 
   if(result) {
     if(result == CURLE_AGAIN) {
       ctx->nw_out_blocked = 1;
       return NGHTTP2_ERR_WOULDBLOCK;
     }
     failf(data, "Failed sending HTTP2 data");
     return NGHTTP2_ERR_CALLBACK_FAILURE;
   }
 
   if(!nwritten) {
     ctx->nw_out_blocked = 1;
     return NGHTTP2_ERR_WOULDBLOCK;
   }
   return (nwritten  > SSIZE_T_MAX) ?
     NGHTTP2_ERR_CALLBACK_FAILURE : (ssize_t)nwritten;
 }
 
 
 /* We pass a pointer to this struct in the push callback, but the contents of
    the struct are hidden from the user. */
 struct curl_pushheaders {
   struct Curl_easy *data;
   struct h2_stream_ctx *stream;
   const nghttp2_push_promise *frame;
 };
 
 /*
  * push header access function. Only to be used from within the push callback
  */
 char *curl_pushheader_bynum(struct curl_pushheaders *h, size_t num)
 {
   /* Verify that we got a good easy handle in the push header struct, mostly to
      detect rubbish input fast(er). */
   if(!h || !GOOD_EASY_HANDLE(h->data))
     return NULL;
   else {
     if(h->stream && num < h->stream->push_headers_used)
       return h->stream->push_headers[num];
   }
   return NULL;
 }
 
 /*
  * push header access function. Only to be used from within the push callback
  */
 char *curl_pushheader_byname(struct curl_pushheaders *h, const char *header)
 {
   struct h2_stream_ctx *stream;
   size_t len;
   size_t i;
   /* Verify that we got a good easy handle in the push header struct,
      mostly to detect rubbish input fast(er). Also empty header name
      is just a rubbish too. We have to allow ":" at the beginning of
      the header, but header == ":" must be rejected. If we have ':' in
      the middle of header, it could be matched in middle of the value,
      this is because we do prefix match.*/
   if(!h || !GOOD_EASY_HANDLE(h->data) || !header || !header[0] ||
      !strcmp(header, ":") || strchr(header + 1, ':'))
     return NULL;
 
   stream = h->stream;
   if(!stream)
     return NULL;
 
   len = strlen(header);
   for(i = 0; i < stream->push_headers_used; i++) {
     if(!strncmp(header, stream->push_headers[i], len)) {
       /* sub-match, make sure that it is followed by a colon */
       if(stream->push_headers[i][len] != ':')
         continue;
       return &stream->push_headers[i][len + 1];
     }
   }
   return NULL;
 }
 
 static struct Curl_easy *h2_duphandle(struct Curl_cfilter *cf,
                                       struct Curl_easy *data)
 {
   struct Curl_easy *second = curl_easy_duphandle(data);
   if(second) {
     struct h2_stream_ctx *second_stream;
     http2_data_setup(cf, second, &second_stream);
     second->state.priority.weight = data->state.priority.weight;
   }
   return second;
 }
 
 static int set_transfer_url(struct Curl_easy *data,
                             struct curl_pushheaders *hp)
 {
   const char *v;
   CURLUcode uc;
   char *url = NULL;
   int rc = 0;
   CURLU *u = curl_url();
 
   if(!u)
     return 5;
 
   v = curl_pushheader_byname(hp, HTTP_PSEUDO_SCHEME);
   if(v) {
     uc = curl_url_set(u, CURLUPART_SCHEME, v, 0);
     if(uc) {
       rc = 1;
       goto fail;
     }
   }
 
   v = curl_pushheader_byname(hp, HTTP_PSEUDO_AUTHORITY);
   if(v) {
     uc = Curl_url_set_authority(u, v);
     if(uc) {
       rc = 2;
       goto fail;
     }
   }
 
   v = curl_pushheader_byname(hp, HTTP_PSEUDO_PATH);
   if(v) {
     uc = curl_url_set(u, CURLUPART_PATH, v, 0);
     if(uc) {
       rc = 3;
       goto fail;
     }
   }
 
   uc = curl_url_get(u, CURLUPART_URL, &url, 0);
   if(uc)
     rc = 4;
 fail:
   curl_url_cleanup(u);
   if(rc)
     return rc;
 
   if(data->state.url_alloc)
     free(data->state.url);
   data->state.url_alloc = TRUE;
   data->state.url = url;
   return 0;
 }
 
 static void discard_newhandle(struct Curl_cfilter *cf,
                               struct Curl_easy *newhandle)
 {
   http2_data_done(cf, newhandle);
   (void)Curl_close(&newhandle);
 }
 
 static int push_promise(struct Curl_cfilter *cf,
                         struct Curl_easy *data,
                         const nghttp2_push_promise *frame)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   int rv; /* one of the CURL_PUSH_* defines */
 
   CURL_TRC_CF(data, cf, "[%d] PUSH_PROMISE received",
               frame->promised_stream_id);
   if(data->multi->push_cb) {
     struct h2_stream_ctx *stream;
     struct h2_stream_ctx *newstream;
     struct curl_pushheaders heads;
     CURLMcode rc;
     CURLcode result;
     /* clone the parent */
     struct Curl_easy *newhandle = h2_duphandle(cf, data);
     if(!newhandle) {
       infof(data, "failed to duplicate handle");
       rv = CURL_PUSH_DENY; /* FAIL HARD */
       goto fail;
     }
 
     stream = H2_STREAM_CTX(ctx, data);
     if(!stream) {
       failf(data, "Internal NULL stream");
       discard_newhandle(cf, newhandle);
       rv = CURL_PUSH_DENY;
       goto fail;
     }
 
     heads.data = data;
     heads.stream = stream;
     heads.frame = frame;
 
     rv = set_transfer_url(newhandle, &heads);
     if(rv) {
       CURL_TRC_CF(data, cf, "[%d] PUSH_PROMISE, failed to set url -> %d",
                   frame->promised_stream_id, rv);
       discard_newhandle(cf, newhandle);
       rv = CURL_PUSH_DENY;
       goto fail;
     }
 
     Curl_set_in_callback(data, TRUE);
     rv = data->multi->push_cb(data, newhandle,
                               stream->push_headers_used, &heads,
                               data->multi->push_userp);
     Curl_set_in_callback(data, FALSE);
 
     /* free the headers again */
     free_push_headers(stream);
 
     if(rv) {
       DEBUGASSERT((rv > CURL_PUSH_OK) && (rv <= CURL_PUSH_ERROROUT));
       /* denied, kill off the new handle again */
       CURL_TRC_CF(data, cf, "[%d] PUSH_PROMISE, denied by application -> %d",
                   frame->promised_stream_id, rv);
       discard_newhandle(cf, newhandle);
       goto fail;
     }
 
     /* approved, add to the multi handle for processing. This
      * assigns newhandle->mid. For the new `mid` we assign the
      * h2_stream instance and remember the stream_id already known. */
     rc = Curl_multi_add_perform(data->multi, newhandle, cf->conn);
     if(rc) {
       infof(data, "failed to add handle to multi");
       discard_newhandle(cf, newhandle);
       rv = CURL_PUSH_DENY;
       goto fail;
     }
 
     result = http2_data_setup(cf, newhandle, &newstream);
     if(result) {
       failf(data, "error setting up stream: %d", result);
       discard_newhandle(cf, newhandle);
       rv = CURL_PUSH_DENY;
       goto fail;
     }
 
     DEBUGASSERT(newstream);
     newstream->id = frame->promised_stream_id;
     newhandle->req.maxdownload = -1;
     newhandle->req.size = -1;
 
     CURL_TRC_CF(data, cf, "promise easy handle added to multi, mid=%u",
                 newhandle->mid);
     rv = nghttp2_session_set_stream_user_data(ctx->h2,
                                               newstream->id,
                                               newhandle);
     if(rv) {
       infof(data, "failed to set user_data for stream %u",
             newstream->id);
       DEBUGASSERT(0);
       rv = CURL_PUSH_DENY;
       goto fail;
     }
 
     /* success, remember max stream id processed */
     if(newstream->id > ctx->local_max_sid)
       ctx->local_max_sid = newstream->id;
   }
   else {
     CURL_TRC_CF(data, cf, "Got PUSH_PROMISE, ignore it");
     rv = CURL_PUSH_DENY;
   }
 fail:
   return rv;
 }
 
 static void h2_xfer_write_resp_hd(struct Curl_cfilter *cf,
                                   struct Curl_easy *data,
                                   struct h2_stream_ctx *stream,
                                   const char *buf, size_t blen, bool eos)
 {
 
   /* If we already encountered an error, skip further writes */
   if(!stream->xfer_result) {
     stream->xfer_result = Curl_xfer_write_resp_hd(data, buf, blen, eos);
     if(!stream->xfer_result && !eos)
       stream->xfer_result = cf_h2_update_local_win(cf, data, stream);
     if(stream->xfer_result)
       CURL_TRC_CF(data, cf, "[%d] error %d writing %zu bytes of headers",
                   stream->id, stream->xfer_result, blen);
   }
 }
 
 static void h2_xfer_write_resp(struct Curl_cfilter *cf,
                                struct Curl_easy *data,
                                struct h2_stream_ctx *stream,
                                const char *buf, size_t blen, bool eos)
 {
 
   /* If we already encountered an error, skip further writes */
   if(!stream->xfer_result)
     stream->xfer_result = Curl_xfer_write_resp(data, buf, blen, eos);
   /* If the transfer write is errored, we do not want any more data */
   if(stream->xfer_result) {
     struct cf_h2_ctx *ctx = cf->ctx;
     CURL_TRC_CF(data, cf, "[%d] error %d writing %zu bytes of data, "
                 "RST-ing stream",
                 stream->id, stream->xfer_result, blen);
     nghttp2_submit_rst_stream(ctx->h2, 0, stream->id,
                               (uint32_t)NGHTTP2_ERR_CALLBACK_FAILURE);
   }
   else if(!stream->write_paused && Curl_xfer_write_is_paused(data)) {
     CURL_TRC_CF(data, cf, "[%d] stream output paused", stream->id);
     stream->write_paused = TRUE;
   }
   else if(stream->write_paused && !Curl_xfer_write_is_paused(data)) {
     CURL_TRC_CF(data, cf, "[%d] stream output unpaused", stream->id);
     stream->write_paused = FALSE;
   }
 
   if(!stream->xfer_result && !eos)
     stream->xfer_result = cf_h2_update_local_win(cf, data, stream);
 }
 
 static CURLcode on_stream_frame(struct Curl_cfilter *cf,
                                 struct Curl_easy *data,
                                 const nghttp2_frame *frame)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   struct h2_stream_ctx *stream = H2_STREAM_CTX(ctx, data);
   int32_t stream_id = frame->hd.stream_id;
   int rv;
 
   if(!stream) {
     CURL_TRC_CF(data, cf, "[%d] No stream_ctx set", stream_id);
     return CURLE_FAILED_INIT;
   }
 
   switch(frame->hd.type) {
   case NGHTTP2_DATA:
     CURL_TRC_CF(data, cf, "[%d] DATA, window=%d/%d",
                 stream_id,
                 nghttp2_session_get_stream_effective_recv_data_length(
                   ctx->h2, stream->id),
                 nghttp2_session_get_stream_effective_local_window_size(
                   ctx->h2, stream->id));
     /* If !body started on this stream, then receiving DATA is illegal. */
     if(!stream->bodystarted) {
       rv = nghttp2_submit_rst_stream(ctx->h2, NGHTTP2_FLAG_NONE,
                                      stream_id, NGHTTP2_PROTOCOL_ERROR);
 
       if(nghttp2_is_fatal(rv)) {
         return CURLE_RECV_ERROR;
       }
     }
     break;
   case NGHTTP2_HEADERS:
     if(stream->bodystarted) {
       /* Only valid HEADERS after body started is trailer HEADERS. We
          buffer them in on_header callback. */
       break;
     }
 
     /* nghttp2 guarantees that :status is received, and we store it to
        stream->status_code. Fuzzing has proven this can still be reached
        without status code having been set. */
     if(stream->status_code == -1)
       return CURLE_RECV_ERROR;
 
     /* Only final status code signals the end of header */
     if(stream->status_code / 100 != 1)
       stream->bodystarted = TRUE;
     else
       stream->status_code = -1;
 
     h2_xfer_write_resp_hd(cf, data, stream, STRCONST("\r\n"), stream->closed);
 
     if(stream->status_code / 100 != 1) {
       stream->resp_hds_complete = TRUE;
     }
     Curl_multi_mark_dirty(data);
     break;
   case NGHTTP2_PUSH_PROMISE:
     rv = push_promise(cf, data, &frame->push_promise);
     if(rv) { /* deny! */
       DEBUGASSERT((rv > CURL_PUSH_OK) && (rv <= CURL_PUSH_ERROROUT));
       rv = nghttp2_submit_rst_stream(ctx->h2, NGHTTP2_FLAG_NONE,
                                      frame->push_promise.promised_stream_id,
                                      NGHTTP2_CANCEL);
       if(nghttp2_is_fatal(rv))
         return CURLE_SEND_ERROR;
       else if(rv == CURL_PUSH_ERROROUT) {
         CURL_TRC_CF(data, cf, "[%d] fail in PUSH_PROMISE received",
                     stream_id);
         return CURLE_RECV_ERROR;
       }
     }
     break;
   case NGHTTP2_RST_STREAM:
     stream->closed = TRUE;
     if(frame->rst_stream.error_code) {
       stream->reset = TRUE;
     }
     Curl_multi_mark_dirty(data);
     break;
   case NGHTTP2_WINDOW_UPDATE:
     if(CURL_WANT_SEND(data) && Curl_bufq_is_empty(&stream->sendbuf)) {
       /* need more data, force processing of transfer */
       Curl_multi_mark_dirty(data);
     }
     else if(!Curl_bufq_is_empty(&stream->sendbuf)) {
       /* resume the potentially suspended stream */
       rv = nghttp2_session_resume_data(ctx->h2, stream->id);
       if(nghttp2_is_fatal(rv))
         return CURLE_SEND_ERROR;
     }
     break;
   default:
     break;
   }
 
   if(frame->hd.flags & NGHTTP2_FLAG_END_STREAM) {
     if(!stream->closed && !stream->body_eos &&
        ((stream->status_code >= 400) || (stream->status_code < 200))) {
       /* The server did not give us a positive response and we are not
        * done uploading the request body. We need to stop doing that and
        * also inform the server that we aborted our side. */
       CURL_TRC_CF(data, cf, "[%d] EOS frame with unfinished upload and "
                   "HTTP status %d, abort upload by RST",
                   stream_id, stream->status_code);
       nghttp2_submit_rst_stream(ctx->h2, NGHTTP2_FLAG_NONE,
                                 stream->id, NGHTTP2_STREAM_CLOSED);
       stream->closed = TRUE;
     }
     Curl_multi_mark_dirty(data);
   }
   return CURLE_OK;
 }
 
 #ifndef CURL_DISABLE_VERBOSE_STRINGS
 static int fr_print(const nghttp2_frame *frame, char *buffer, size_t blen)
 {
   switch(frame->hd.type) {
     case NGHTTP2_DATA: {
       return msnprintf(buffer, blen,
                        "FRAME[DATA, len=%d, eos=%d, padlen=%d]",
                        (int)frame->hd.length,
                        !!(frame->hd.flags & NGHTTP2_FLAG_END_STREAM),
                        (int)frame->data.padlen);
     }
     case NGHTTP2_HEADERS: {
       return msnprintf(buffer, blen,
                        "FRAME[HEADERS, len=%d, hend=%d, eos=%d]",
                        (int)frame->hd.length,
                        !!(frame->hd.flags & NGHTTP2_FLAG_END_HEADERS),
                        !!(frame->hd.flags & NGHTTP2_FLAG_END_STREAM));
     }
     case NGHTTP2_PRIORITY: {
       return msnprintf(buffer, blen,
                        "FRAME[PRIORITY, len=%d, flags=%d]",
                        (int)frame->hd.length, frame->hd.flags);
     }
     case NGHTTP2_RST_STREAM: {
       return msnprintf(buffer, blen,
                        "FRAME[RST_STREAM, len=%d, flags=%d, error=%u]",
                        (int)frame->hd.length, frame->hd.flags,
                        frame->rst_stream.error_code);
     }
     case NGHTTP2_SETTINGS: {
       if(frame->hd.flags & NGHTTP2_FLAG_ACK) {
         return msnprintf(buffer, blen, "FRAME[SETTINGS, ack=1]");
       }
       return msnprintf(buffer, blen,
                        "FRAME[SETTINGS, len=%d]", (int)frame->hd.length);
     }
     case NGHTTP2_PUSH_PROMISE: {
       return msnprintf(buffer, blen,
                        "FRAME[PUSH_PROMISE, len=%d, hend=%d]",
                        (int)frame->hd.length,
                        !!(frame->hd.flags & NGHTTP2_FLAG_END_HEADERS));
     }
     case NGHTTP2_PING: {
       return msnprintf(buffer, blen,
                        "FRAME[PING, len=%d, ack=%d]",
                        (int)frame->hd.length,
                        frame->hd.flags&NGHTTP2_FLAG_ACK);
     }
     case NGHTTP2_GOAWAY: {
       char scratch[128];
       size_t s_len = CURL_ARRAYSIZE(scratch);
       size_t len = (frame->goaway.opaque_data_len < s_len) ?
         frame->goaway.opaque_data_len : s_len-1;
       if(len)
         memcpy(scratch, frame->goaway.opaque_data, len);
       scratch[len] = '\0';
       return msnprintf(buffer, blen, "FRAME[GOAWAY, error=%d, reason='%s', "
                        "last_stream=%d]", frame->goaway.error_code,
                        scratch, frame->goaway.last_stream_id);
     }
     case NGHTTP2_WINDOW_UPDATE: {
       return msnprintf(buffer, blen,
                        "FRAME[WINDOW_UPDATE, incr=%d]",
                        frame->window_update.window_size_increment);
     }
     default:
       return msnprintf(buffer, blen, "FRAME[%d, len=%d, flags=%d]",
                        frame->hd.type, (int)frame->hd.length,
                        frame->hd.flags);
   }
 }
 
 static int on_frame_send(nghttp2_session *session, const nghttp2_frame *frame,
                          void *userp)
 {
   struct Curl_cfilter *cf = userp;
   struct cf_h2_ctx *ctx = cf->ctx;
   struct Curl_easy *data = CF_DATA_CURRENT(cf);
 
   (void)session;
   DEBUGASSERT(data);
   if(data && Curl_trc_cf_is_verbose(cf, data)) {
     char buffer[256];
     int len;
     len = fr_print(frame, buffer, sizeof(buffer)-1);
     buffer[len] = 0;
     CURL_TRC_CF(data, cf, "[%d] -> %s", frame->hd.stream_id, buffer);
   }
   if((frame->hd.type == NGHTTP2_GOAWAY) && !ctx->sent_goaway) {
     /* A GOAWAY not initiated by us, but by nghttp2 itself on detecting
      * a protocol error on the connection */
     failf(data, "nghttp2 shuts down connection with error %d: %s",
           frame->goaway.error_code,
           nghttp2_http2_strerror(frame->goaway.error_code));
   }
   return 0;
 }
 #endif /* !CURL_DISABLE_VERBOSE_STRINGS */
 
 static int on_frame_recv(nghttp2_session *session, const nghttp2_frame *frame,
                          void *userp)
 {
   struct Curl_cfilter *cf = userp;
   struct cf_h2_ctx *ctx = cf->ctx;
   struct Curl_easy *data = CF_DATA_CURRENT(cf), *data_s;
   int32_t stream_id = frame->hd.stream_id;
 
   DEBUGASSERT(data);
 #ifndef CURL_DISABLE_VERBOSE_STRINGS
   if(Curl_trc_cf_is_verbose(cf, data)) {
     char buffer[256];
     int len;
     len = fr_print(frame, buffer, sizeof(buffer)-1);
     buffer[len] = 0;
     CURL_TRC_CF(data, cf, "[%d] <- %s",frame->hd.stream_id, buffer);
   }
 #endif /* !CURL_DISABLE_VERBOSE_STRINGS */
 
   if(!stream_id) {
     /* stream ID zero is for connection-oriented stuff */
     DEBUGASSERT(data);
     switch(frame->hd.type) {
     case NGHTTP2_SETTINGS: {
       if(!(frame->hd.flags & NGHTTP2_FLAG_ACK)) {
         uint32_t max_conn = ctx->max_concurrent_streams;
         ctx->max_concurrent_streams = nghttp2_session_get_remote_settings(
             session, NGHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS);
         ctx->enable_push = nghttp2_session_get_remote_settings(
             session, NGHTTP2_SETTINGS_ENABLE_PUSH) != 0;
         CURL_TRC_CF(data, cf, "[0] MAX_CONCURRENT_STREAMS: %d",
                     ctx->max_concurrent_streams);
         CURL_TRC_CF(data, cf, "[0] ENABLE_PUSH: %s",
                     ctx->enable_push ? "TRUE" : "false");
         if(data && max_conn != ctx->max_concurrent_streams) {
           /* only signal change if the value actually changed */
           CURL_TRC_CF(data, cf, "[0] notify MAX_CONCURRENT_STREAMS: %u",
                       ctx->max_concurrent_streams);
           Curl_multi_connchanged(data->multi);
         }
         /* Since the initial stream window is 64K, a request might be on HOLD,
          * due to exhaustion. The (initial) SETTINGS may announce a much larger
          * window and *assume* that we treat this like a WINDOW_UPDATE. Some
          * servers send an explicit WINDOW_UPDATE, but not all seem to do that.
          * To be safe, we UNHOLD a stream in order not to stall. */
         if(CURL_WANT_SEND(data))
           Curl_multi_mark_dirty(data);
       }
       break;
     }
     case NGHTTP2_GOAWAY:
       ctx->rcvd_goaway = TRUE;
       ctx->goaway_error = frame->goaway.error_code;
       ctx->remote_max_sid = frame->goaway.last_stream_id;
       if(data) {
         infof(data, "received GOAWAY, error=%u, last_stream=%u",
                     ctx->goaway_error, ctx->remote_max_sid);
         Curl_multi_connchanged(data->multi);
       }
       break;
     default:
       break;
     }
     return 0;
   }
 
   data_s = nghttp2_session_get_stream_user_data(session, stream_id);
   if(!data_s) {
     CURL_TRC_CF(data, cf, "[%d] No Curl_easy associated", stream_id);
     return 0;
   }
 
   return on_stream_frame(cf, data_s, frame) ? NGHTTP2_ERR_CALLBACK_FAILURE : 0;
 }
 
 static int cf_h2_on_invalid_frame_recv(nghttp2_session *session,
                                        const nghttp2_frame *frame,
                                        int ngerr, void *userp)
 {
   struct Curl_cfilter *cf = userp;
   struct cf_h2_ctx *ctx = cf->ctx;
   struct Curl_easy *data;
   int32_t stream_id = frame->hd.stream_id;
 
   data = nghttp2_session_get_stream_user_data(session, stream_id);
   if(data) {
     struct h2_stream_ctx *stream;
 #ifndef CURL_DISABLE_VERBOSE_STRINGS
     char buffer[256];
     int len;
     len = fr_print(frame, buffer, sizeof(buffer)-1);
     buffer[len] = 0;
     failf(data, "[HTTP2] [%d] received invalid frame: %s, error %d: %s",
           stream_id, buffer, ngerr, nghttp2_strerror(ngerr));
 #endif /* !CURL_DISABLE_VERBOSE_STRINGS */
     stream = H2_STREAM_CTX(ctx, data);
     if(stream) {
       nghttp2_submit_rst_stream(ctx->h2, NGHTTP2_FLAG_NONE,
                                 stream->id, NGHTTP2_STREAM_CLOSED);
       stream->error = ngerr;
       stream->closed = TRUE;
       stream->reset = TRUE;
       return 0;  /* keep the connection alive */
     }
   }
   return NGHTTP2_ERR_CALLBACK_FAILURE;
 }
 
 static int on_data_chunk_recv(nghttp2_session *session, uint8_t flags,
                               int32_t stream_id,
                               const uint8_t *mem, size_t len, void *userp)
 {
   struct Curl_cfilter *cf = userp;
   struct cf_h2_ctx *ctx = cf->ctx;
   struct h2_stream_ctx *stream;
   struct Curl_easy *data_s;
   (void)flags;
 
   DEBUGASSERT(stream_id); /* should never be a zero stream ID here */
   DEBUGASSERT(CF_DATA_CURRENT(cf));
 
   /* get the stream from the hash based on Stream ID */
   data_s = nghttp2_session_get_stream_user_data(session, stream_id);
   if(!data_s) {
     /* Receiving a Stream ID not in the hash should not happen - unless
        we have aborted a transfer artificially and there were more data
        in the pipeline. Silently ignore. */
     CURL_TRC_CF(CF_DATA_CURRENT(cf), cf, "[%d] Data for unknown",
                 stream_id);
     /* consumed explicitly as no one will read it */
     nghttp2_session_consume(session, stream_id, len);
     return 0;
   }
 
   stream = H2_STREAM_CTX(ctx, data_s);
   if(!stream)
     return NGHTTP2_ERR_CALLBACK_FAILURE;
 
   h2_xfer_write_resp(cf, data_s, stream, (const char *)mem, len, FALSE);
 
   nghttp2_session_consume(ctx->h2, stream_id, len);
   stream->nrcvd_data += (curl_off_t)len;
   return 0;
 }
 
 static int on_stream_close(nghttp2_session *session, int32_t stream_id,
                            uint32_t error_code, void *userp)
 {
   struct Curl_cfilter *cf = userp;
   struct cf_h2_ctx *ctx = cf->ctx;
   struct Curl_easy *data_s, *call_data = CF_DATA_CURRENT(cf);
   struct h2_stream_ctx *stream;
   int rv;
   (void)session;
 
   DEBUGASSERT(call_data);
   /* stream id 0 is the connection, do not look there for streams. */
   data_s = stream_id ?
     nghttp2_session_get_stream_user_data(session, stream_id) : NULL;
   if(!data_s) {
     CURL_TRC_CF(call_data, cf,
                 "[%d] on_stream_close, no easy set on stream", stream_id);
     return 0;
   }
   if(!GOOD_EASY_HANDLE(data_s)) {
     /* nghttp2 still has an easy registered for the stream which has
      * been freed be libcurl. This points to a code path that does not
      * trigger DONE or DETACH events as it must. */
     CURL_TRC_CF(call_data, cf,
                 "[%d] on_stream_close, not a GOOD easy on stream", stream_id);
     (void)nghttp2_session_set_stream_user_data(session, stream_id, 0);
     return NGHTTP2_ERR_CALLBACK_FAILURE;
   }
   stream = H2_STREAM_CTX(ctx, data_s);
   if(!stream) {
     CURL_TRC_CF(data_s, cf,
                 "[%d] on_stream_close, GOOD easy but no stream", stream_id);
     return NGHTTP2_ERR_CALLBACK_FAILURE;
   }
 
   stream->closed = TRUE;
   stream->error = error_code;
   if(stream->error) {
     stream->reset = TRUE;
   }
 
   if(stream->error)
     CURL_TRC_CF(data_s, cf, "[%d] RESET: %s (err %d)",
               stream_id, nghttp2_http2_strerror(error_code), error_code);
   else
     CURL_TRC_CF(data_s, cf, "[%d] CLOSED", stream_id);
   Curl_multi_mark_dirty(data_s);
 
   /* remove `data_s` from the nghttp2 stream */
   rv = nghttp2_session_set_stream_user_data(session, stream_id, 0);
   if(rv) {
     infof(data_s, "http/2: failed to clear user_data for stream %u",
           stream_id);
     DEBUGASSERT(0);
   }
   return 0;
 }
 
 static int on_begin_headers(nghttp2_session *session,
                             const nghttp2_frame *frame, void *userp)
 {
   struct Curl_cfilter *cf = userp;
   struct cf_h2_ctx *ctx = cf->ctx;
   struct h2_stream_ctx *stream;
   struct Curl_easy *data_s = NULL;
 
   (void)cf;
   data_s = nghttp2_session_get_stream_user_data(session, frame->hd.stream_id);
   if(!data_s) {
     return 0;
   }
 
   if(frame->hd.type != NGHTTP2_HEADERS) {
     return 0;
   }
 
   stream = H2_STREAM_CTX(ctx, data_s);
   if(!stream || !stream->bodystarted) {
     return 0;
   }
 
   return 0;
 }
 
 static void cf_h2_header_error(struct Curl_cfilter *cf,
                                struct Curl_easy *data,
                                struct h2_stream_ctx *stream,
                                CURLcode result)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
 
   failf(data, "Error receiving HTTP2 header: %d(%s)", result,
         curl_easy_strerror(result));
   if(stream) {
     nghttp2_submit_rst_stream(ctx->h2, NGHTTP2_FLAG_NONE,
                               stream->id, NGHTTP2_STREAM_CLOSED);
     stream->closed = TRUE;
     stream->reset = TRUE;
   }
 }
 
 /* frame->hd.type is either NGHTTP2_HEADERS or NGHTTP2_PUSH_PROMISE */
 static int on_header(nghttp2_session *session, const nghttp2_frame *frame,
                      const uint8_t *name, size_t namelen,
                      const uint8_t *value, size_t valuelen,
                      uint8_t flags,
                      void *userp)
 {
   struct Curl_cfilter *cf = userp;
   struct cf_h2_ctx *ctx = cf->ctx;
   struct h2_stream_ctx *stream;
   struct Curl_easy *data_s;
   int32_t stream_id = frame->hd.stream_id;
   CURLcode result;
   (void)flags;
 
   DEBUGASSERT(stream_id); /* should never be a zero stream ID here */
 
   /* get the stream from the hash based on Stream ID */
   data_s = nghttp2_session_get_stream_user_data(session, stream_id);
   if(!GOOD_EASY_HANDLE(data_s))
     /* Receiving a Stream ID not in the hash should not happen, this is an
        internal error more than anything else! */
     return NGHTTP2_ERR_CALLBACK_FAILURE;
 
   stream = H2_STREAM_CTX(ctx, data_s);
   if(!stream) {
     failf(data_s, "Internal NULL stream");
     return NGHTTP2_ERR_CALLBACK_FAILURE;
   }
 
   /* Store received PUSH_PROMISE headers to be used when the subsequent
      PUSH_PROMISE callback comes */
   if(frame->hd.type == NGHTTP2_PUSH_PROMISE) {
     char *h;
 
     if(!strcmp(HTTP_PSEUDO_AUTHORITY, (const char *)name)) {
       /* pseudo headers are lower case */
       int rc = 0;
       char *check = aprintf("%s:%d", cf->conn->host.name,
                             cf->conn->remote_port);
       if(!check)
         /* no memory */
         return NGHTTP2_ERR_CALLBACK_FAILURE;
       if(!curl_strequal(check, (const char *)value) &&
          ((cf->conn->remote_port != cf->conn->given->defport) ||
           !curl_strequal(cf->conn->host.name, (const char *)value))) {
         /* This is push is not for the same authority that was asked for in
          * the URL. RFC 7540 section 8.2 says: "A client MUST treat a
          * PUSH_PROMISE for which the server is not authoritative as a stream
          * error of type PROTOCOL_ERROR."
          */
         (void)nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE,
                                         stream_id, NGHTTP2_PROTOCOL_ERROR);
         rc = NGHTTP2_ERR_CALLBACK_FAILURE;
       }
       free(check);
       if(rc)
         return rc;
     }
 
     if(!stream->push_headers) {
       stream->push_headers_alloc = 10;
       stream->push_headers = malloc(stream->push_headers_alloc *
                                     sizeof(char *));
       if(!stream->push_headers)
         return NGHTTP2_ERR_CALLBACK_FAILURE;
       stream->push_headers_used = 0;
     }
     else if(stream->push_headers_used ==
             stream->push_headers_alloc) {
       char **headp;
       if(stream->push_headers_alloc > 1000) {
         /* this is beyond crazy many headers, bail out */
         failf(data_s, "Too many PUSH_PROMISE headers");
         free_push_headers(stream);
         return NGHTTP2_ERR_CALLBACK_FAILURE;
       }
       stream->push_headers_alloc *= 2;
       headp = realloc(stream->push_headers,
                       stream->push_headers_alloc * sizeof(char *));
       if(!headp) {
         free_push_headers(stream);
         return NGHTTP2_ERR_CALLBACK_FAILURE;
       }
       stream->push_headers = headp;
     }
     h = aprintf("%s:%s", name, value);
     if(h)
       stream->push_headers[stream->push_headers_used++] = h;
     return 0;
   }
 
   if(stream->bodystarted) {
     /* This is a trailer */
     CURL_TRC_CF(data_s, cf, "[%d] trailer: %.*s: %.*s",
                 stream->id, (int)namelen, name, (int)valuelen, value);
     result = Curl_dynhds_add(&stream->resp_trailers,
                              (const char *)name, namelen,
                              (const char *)value, valuelen);
     if(result) {
       cf_h2_header_error(cf, data_s, stream, result);
       return NGHTTP2_ERR_CALLBACK_FAILURE;
     }
 
     return 0;
   }
 
   if(namelen == sizeof(HTTP_PSEUDO_STATUS) - 1 &&
      memcmp(HTTP_PSEUDO_STATUS, name, namelen) == 0) {
     /* nghttp2 guarantees :status is received first and only once. */
     char buffer[32];
     result = Curl_http_decode_status(&stream->status_code,
                                      (const char *)value, valuelen);
     if(result) {
       cf_h2_header_error(cf, data_s, stream, result);
       return NGHTTP2_ERR_CALLBACK_FAILURE;
     }
     msnprintf(buffer, sizeof(buffer), HTTP_PSEUDO_STATUS ":%u\r",
               stream->status_code);
     result = Curl_headers_push(data_s, buffer, CURLH_PSEUDO);
     if(result) {
       cf_h2_header_error(cf, data_s, stream, result);
       return NGHTTP2_ERR_CALLBACK_FAILURE;
     }
     curlx_dyn_reset(&ctx->scratch);
     result = curlx_dyn_addn(&ctx->scratch, STRCONST("HTTP/2 "));
     if(!result)
       result = curlx_dyn_addn(&ctx->scratch, value, valuelen);
     if(!result)
       result = curlx_dyn_addn(&ctx->scratch, STRCONST(" \r\n"));
     if(!result)
       h2_xfer_write_resp_hd(cf, data_s, stream, curlx_dyn_ptr(&ctx->scratch),
                             curlx_dyn_len(&ctx->scratch), FALSE);
     if(result) {
       cf_h2_header_error(cf, data_s, stream, result);
       return NGHTTP2_ERR_CALLBACK_FAILURE;
     }
     /* if we receive data for another handle, wake that up */
     if(CF_DATA_CURRENT(cf) != data_s)
       Curl_multi_mark_dirty(data_s);
 
     CURL_TRC_CF(data_s, cf, "[%d] status: HTTP/2 %03d",
                 stream->id, stream->status_code);
     return 0;
   }
 
   /* nghttp2 guarantees that namelen > 0, and :status was already
      received, and this is not pseudo-header field . */
   /* convert to an HTTP1-style header */
   curlx_dyn_reset(&ctx->scratch);
   result = curlx_dyn_addn(&ctx->scratch, (const char *)name, namelen);
   if(!result)
     result = curlx_dyn_addn(&ctx->scratch, STRCONST(": "));
   if(!result)
     result = curlx_dyn_addn(&ctx->scratch, (const char *)value, valuelen);
   if(!result)
     result = curlx_dyn_addn(&ctx->scratch, STRCONST("\r\n"));
   if(!result)
     h2_xfer_write_resp_hd(cf, data_s, stream, curlx_dyn_ptr(&ctx->scratch),
                           curlx_dyn_len(&ctx->scratch), FALSE);
   if(result) {
     cf_h2_header_error(cf, data_s, stream, result);
     return NGHTTP2_ERR_CALLBACK_FAILURE;
   }
   /* if we receive data for another handle, wake that up */
   if(CF_DATA_CURRENT(cf) != data_s)
     Curl_multi_mark_dirty(data_s);
 
   CURL_TRC_CF(data_s, cf, "[%d] header: %.*s: %.*s",
               stream->id, (int)namelen, name, (int)valuelen, value);
 
   return 0; /* 0 is successful */
 }
 
 static ssize_t req_body_read_callback(nghttp2_session *session,
                                       int32_t stream_id,
                                       uint8_t *buf, size_t length,
                                       uint32_t *data_flags,
                                       nghttp2_data_source *source,
                                       void *userp)
 {
   struct Curl_cfilter *cf = userp;
   struct cf_h2_ctx *ctx = cf->ctx;
   struct Curl_easy *data_s;
   struct h2_stream_ctx *stream = NULL;
   CURLcode result;
   ssize_t nread;
   size_t n;
   (void)source;
 
   (void)cf;
   if(!stream_id)
     return NGHTTP2_ERR_INVALID_ARGUMENT;
 
   /* get the stream from the hash based on Stream ID, stream ID zero is for
      connection-oriented stuff */
   data_s = nghttp2_session_get_stream_user_data(session, stream_id);
   if(!data_s)
     /* Receiving a Stream ID not in the hash should not happen, this is an
        internal error more than anything else! */
     return NGHTTP2_ERR_CALLBACK_FAILURE;
 
   stream = H2_STREAM_CTX(ctx, data_s);
   if(!stream)
     return NGHTTP2_ERR_CALLBACK_FAILURE;
 
   result = Curl_bufq_read(&stream->sendbuf, buf, length, &n);
   if(result) {
     if(result != CURLE_AGAIN)
       return NGHTTP2_ERR_CALLBACK_FAILURE;
     nread = 0;
   }
   else
     nread = (ssize_t)n;
 
   CURL_TRC_CF(data_s, cf, "[%d] req_body_read(len=%zu) eos=%d -> %zd, %d",
               stream_id, length, stream->body_eos, nread, result);
 
   if(stream->body_eos && Curl_bufq_is_empty(&stream->sendbuf)) {
     *data_flags = NGHTTP2_DATA_FLAG_EOF;
     return nread;
   }
   return (nread == 0) ? NGHTTP2_ERR_DEFERRED : nread;
 }
 
 #if !defined(CURL_DISABLE_VERBOSE_STRINGS)
 static int error_callback(nghttp2_session *session,
                           const char *msg,
                           size_t len,
                           void *userp)
 {
   struct Curl_cfilter *cf = userp;
   struct Curl_easy *data = CF_DATA_CURRENT(cf);
   (void)session;
   failf(data, "%.*s", (int)len, msg);
   return 0;
 }
 #endif
 
 /*
  * Append headers to ask for an HTTP1.1 to HTTP2 upgrade.
  */
 CURLcode Curl_http2_request_upgrade(struct dynbuf *req,
                                     struct Curl_easy *data)
 {
   CURLcode result;
   char *base64;
   size_t blen;
   struct SingleRequest *k = &data->req;
   uint8_t binsettings[H2_BINSETTINGS_LEN];
   ssize_t binlen; /* length of the binsettings data */
 
   binlen = populate_binsettings(binsettings, data);
   if(binlen <= 0) {
     failf(data, "nghttp2 unexpectedly failed on pack_settings_payload");
     curlx_dyn_free(req);
     return CURLE_FAILED_INIT;
   }
 
   result = curlx_base64url_encode((const char *)binsettings, (size_t)binlen,
                                   &base64, &blen);
   if(result) {
     curlx_dyn_free(req);
     return result;
   }
 
   result = curlx_dyn_addf(req,
                           "Connection: Upgrade, HTTP2-Settings\r\n"
                           "Upgrade: %s\r\n"
                           "HTTP2-Settings: %s\r\n",
                           NGHTTP2_CLEARTEXT_PROTO_VERSION_ID, base64);
   free(base64);
 
   k->upgr101 = UPGR101_H2;
   data->conn->bits.asks_multiplex = TRUE;
 
   return result;
 }
 
 static CURLcode http2_handle_stream_close(struct Curl_cfilter *cf,
                                           struct Curl_easy *data,
                                           struct h2_stream_ctx *stream,
                                           size_t *pnlen)
 {
   CURLcode result;
 
   *pnlen = 0;
   if(stream->error == NGHTTP2_REFUSED_STREAM) {
     CURL_TRC_CF(data, cf, "[%d] REFUSED_STREAM, try again on a new "
                 "connection", stream->id);
     connclose(cf->conn, "REFUSED_STREAM"); /* do not use this anymore */
     data->state.refused_stream = TRUE;
     return CURLE_RECV_ERROR; /* trigger Curl_retry_request() later */
   }
   else if(stream->error != NGHTTP2_NO_ERROR) {
     if(stream->resp_hds_complete && data->req.no_body) {
       CURL_TRC_CF(data, cf, "[%d] error after response headers, but we did "
                   "not want a body anyway, ignore: %s (err %u)",
                   stream->id, nghttp2_http2_strerror(stream->error),
                   stream->error);
       stream->close_handled = TRUE;
       return CURLE_OK;
     }
     failf(data, "HTTP/2 stream %u was not closed cleanly: %s (err %u)",
           stream->id, nghttp2_http2_strerror(stream->error),
           stream->error);
     return CURLE_HTTP2_STREAM;
   }
   else if(stream->reset) {
     failf(data, "HTTP/2 stream %u was reset", stream->id);
     return data->req.bytecount ? CURLE_PARTIAL_FILE : CURLE_HTTP2;
   }
 
   if(!stream->bodystarted) {
     failf(data, "HTTP/2 stream %u was closed cleanly, but before getting "
           " all response header fields, treated as error",
           stream->id);
     return CURLE_HTTP2_STREAM;
   }
 
   if(Curl_dynhds_count(&stream->resp_trailers)) {
     struct dynhds_entry *e;
     struct dynbuf dbuf;
     size_t i;
 
     result = CURLE_OK;
     curlx_dyn_init(&dbuf, DYN_TRAILERS);
     for(i = 0; i < Curl_dynhds_count(&stream->resp_trailers); ++i) {
       e = Curl_dynhds_getn(&stream->resp_trailers, i);
       if(!e)
         break;
       curlx_dyn_reset(&dbuf);
       result = curlx_dyn_addf(&dbuf, "%.*s: %.*s\x0d\x0a",
                             (int)e->namelen, e->name,
                             (int)e->valuelen, e->value);
       if(result)
         break;
       Curl_debug(data, CURLINFO_HEADER_IN, curlx_dyn_ptr(&dbuf),
                  curlx_dyn_len(&dbuf));
       result = Curl_client_write(data, CLIENTWRITE_HEADER|CLIENTWRITE_TRAILER,
                                  curlx_dyn_ptr(&dbuf), curlx_dyn_len(&dbuf));
       if(result)
         break;
     }
     curlx_dyn_free(&dbuf);
     if(result)
       goto out;
   }
 
   stream->close_handled = TRUE;
   result = CURLE_OK;
 
 out:
   CURL_TRC_CF(data, cf, "handle_stream_close -> %d, %zu", result, *pnlen);
   return result;
 }
 
 static int sweight_wanted(const struct Curl_easy *data)
 {
   /* 0 weight is not set by user and we take the nghttp2 default one */
   return data->set.priority.weight ?
     data->set.priority.weight : NGHTTP2_DEFAULT_WEIGHT;
 }
 
 static int sweight_in_effect(const struct Curl_easy *data)
 {
   /* 0 weight is not set by user and we take the nghttp2 default one */
   return data->state.priority.weight ?
     data->state.priority.weight : NGHTTP2_DEFAULT_WEIGHT;
 }
 
 /*
  * h2_pri_spec() fills in the pri_spec struct, used by nghttp2 to send weight
  * and dependency to the peer. It also stores the updated values in the state
  * struct.
  */
 
 static void h2_pri_spec(struct cf_h2_ctx *ctx,
                         struct Curl_easy *data,
                         nghttp2_priority_spec *pri_spec)
 {
   struct Curl_data_priority *prio = &data->set.priority;
   struct h2_stream_ctx *depstream = H2_STREAM_CTX(ctx, prio->parent);
   int32_t depstream_id = depstream ? depstream->id : 0;
   nghttp2_priority_spec_init(pri_spec, depstream_id,
                              sweight_wanted(data),
                              data->set.priority.exclusive);
   data->state.priority = *prio;
 }
 
 /*
  * Check if there is been an update in the priority /
  * dependency settings and if so it submits a PRIORITY frame with the updated
  * info.
  * Flush any out data pending in the network buffer.
  */
 static CURLcode h2_progress_egress(struct Curl_cfilter *cf,
                                    struct Curl_easy *data)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   struct h2_stream_ctx *stream = H2_STREAM_CTX(ctx, data);
   int rv = 0;
 
   if(stream && stream->id > 0 &&
      ((sweight_wanted(data) != sweight_in_effect(data)) ||
       (data->set.priority.exclusive != data->state.priority.exclusive) ||
       (data->set.priority.parent != data->state.priority.parent)) ) {
     /* send new weight and/or dependency */
     nghttp2_priority_spec pri_spec;
 
     h2_pri_spec(ctx, data, &pri_spec);
     CURL_TRC_CF(data, cf, "[%d] Queuing PRIORITY", stream->id);
     DEBUGASSERT(stream->id != -1);
     rv = nghttp2_submit_priority(ctx->h2, NGHTTP2_FLAG_NONE,
                                  stream->id, &pri_spec);
     if(rv)
       goto out;
   }
 
   ctx->nw_out_blocked = 0;
   while(!rv && !ctx->nw_out_blocked && nghttp2_session_want_write(ctx->h2))
     rv = nghttp2_session_send(ctx->h2);
 
 out:
   if(nghttp2_is_fatal(rv)) {
     CURL_TRC_CF(data, cf, "nghttp2_session_send error (%s)%d",
                 nghttp2_strerror(rv), rv);
     return CURLE_SEND_ERROR;
   }
   /* Defer flushing during the connect phase so that the SETTINGS and
    * other initial frames are sent together with the first request.
    * Unless we are 'connect_only' where the request will never come. */
   if(!cf->connected && !cf->conn->connect_only)
     return CURLE_OK;
   return nw_out_flush(cf, data);
 }
 
 static CURLcode stream_recv(struct Curl_cfilter *cf, struct Curl_easy *data,
                             struct h2_stream_ctx *stream,
                             char *buf, size_t len, size_t *pnread)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   CURLcode result = CURLE_AGAIN;
 
   (void)buf;
   (void)len;
   *pnread = 0;
 
   if(stream->xfer_result) {
     CURL_TRC_CF(data, cf, "[%d] xfer write failed", stream->id);
     result = stream->xfer_result;
   }
   else if(stream->closed) {
     CURL_TRC_CF(data, cf, "[%d] returning CLOSE", stream->id);
     result = http2_handle_stream_close(cf, data, stream, pnread);
   }
   else if(stream->reset ||
           (ctx->conn_closed && Curl_bufq_is_empty(&ctx->inbufq)) ||
           (ctx->rcvd_goaway && ctx->remote_max_sid < stream->id)) {
     CURL_TRC_CF(data, cf, "[%d] returning ERR", stream->id);
     result = data->req.bytecount ? CURLE_PARTIAL_FILE : CURLE_HTTP2;
   }
 
   if(result && (result != CURLE_AGAIN))
     CURL_TRC_CF(data, cf, "[%d] stream_recv(len=%zu) -> %d, %zu",
                 stream->id, len, result, *pnread);
   return result;
 }
 
 static CURLcode h2_progress_ingress(struct Curl_cfilter *cf,
                                     struct Curl_easy *data,
                                     size_t data_max_bytes)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   struct h2_stream_ctx *stream;
   CURLcode result = CURLE_OK;
   size_t nread;
 
   if(should_close_session(ctx)) {
     CURL_TRC_CF(data, cf, "progress ingress, session is closed");
     return CURLE_HTTP2;
   }
 
   /* Process network input buffer fist */
   if(!Curl_bufq_is_empty(&ctx->inbufq)) {
     CURL_TRC_CF(data, cf, "Process %zu bytes in connection buffer",
                 Curl_bufq_len(&ctx->inbufq));
     if(h2_process_pending_input(cf, data, &result) < 0)
       return result;
   }
 
   /* Receive data from the "lower" filters, e.g. network until
    * it is time to stop due to connection close or us not processing
    * all network input */
   while(!ctx->conn_closed && Curl_bufq_is_empty(&ctx->inbufq)) {
     stream = H2_STREAM_CTX(ctx, data);
     if(stream && (stream->closed || !data_max_bytes)) {
       /* We would like to abort here and stop processing, so that
        * the transfer loop can handle the data/close here. However,
        * this may leave data in underlying buffers that will not
        * be consumed. */
       if(!cf->next || !cf->next->cft->has_data_pending(cf->next, data))
         Curl_multi_mark_dirty(data);
       break;
     }
 
     result = Curl_cf_recv_bufq(cf->next, data, &ctx->inbufq, 0, &nread);
     if(result) {
       if(result != CURLE_AGAIN) {
         failf(data, "Failed receiving HTTP2 data: %d(%s)", result,
               curl_easy_strerror(result));
         return result;
       }
       break;
     }
     else if(nread == 0) {
       CURL_TRC_CF(data, cf, "[0] ingress: connection closed");
       ctx->conn_closed = TRUE;
       break;
     }
     else {
       CURL_TRC_CF(data, cf, "[0] ingress: read %zu bytes", nread);
       data_max_bytes = (data_max_bytes > nread) ? (data_max_bytes - nread) : 0;
     }
 
     if(h2_process_pending_input(cf, data, &result))
       return result;
     CURL_TRC_CF(data, cf, "[0] progress ingress: inbufg=%zu",
                 Curl_bufq_len(&ctx->inbufq));
   }
 
   if(ctx->conn_closed && Curl_bufq_is_empty(&ctx->inbufq)) {
     connclose(cf->conn, "GOAWAY received");
   }
 
   CURL_TRC_CF(data, cf, "[0] progress ingress: done");
   return CURLE_OK;
 }
 
 static CURLcode cf_h2_recv(struct Curl_cfilter *cf, struct Curl_easy *data,
                            char *buf, size_t len, size_t *pnread)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   struct h2_stream_ctx *stream = H2_STREAM_CTX(ctx, data);
   CURLcode result, r2;
   struct cf_call_data save;
 
   *pnread = 0;
   if(!stream) {
     /* Abnormal call sequence: either this transfer has never opened a stream
      * (unlikely) or the transfer has been done, cleaned up its resources, but
      * a read() is called anyway. It is not clear what the calling sequence
      * is for such a case. */
     failf(data, "http/2 recv on a transfer never opened "
           "or already cleared, mid=%u", data->mid);
     return CURLE_HTTP2;
   }
 
   CF_DATA_SAVE(save, cf, data);
 
   result = stream_recv(cf, data, stream, buf, len, pnread);
   if(result && (result != CURLE_AGAIN))
     goto out;
 
   if(result) {
     result = h2_progress_ingress(cf, data, len);
     if(result)
       goto out;
 
     result = stream_recv(cf, data, stream, buf, len, pnread);
   }
 
   if(*pnread > 0) {
     /* Now that we transferred this to the upper layer, we report
      * the actual amount of DATA consumed to the H2 session, so
      * that it adjusts stream flow control */
     nghttp2_session_consume(ctx->h2, stream->id, *pnread);
     if(stream->closed) {
       CURL_TRC_CF(data, cf, "[%d] DRAIN closed stream", stream->id);
       Curl_multi_mark_dirty(data);
     }
   }
 
 out:
   r2 = h2_progress_egress(cf, data);
   if(r2 == CURLE_AGAIN) {
     /* pending data to send, need to be called again. Ideally, we
      * monitor the socket for POLLOUT, but when not SENDING
      * any more, we force processing of the transfer. */
     if(!CURL_WANT_SEND(data))
       Curl_multi_mark_dirty(data);
   }
   else if(r2) {
     result = r2;
   }
   CURL_TRC_CF(data, cf, "[%d] cf_recv(len=%zu) -> %d, %zu, "
               "window=%d/%d, connection %d/%d",
               stream->id, len, result, *pnread,
               nghttp2_session_get_stream_effective_recv_data_length(
                 ctx->h2, stream->id),
               nghttp2_session_get_stream_effective_local_window_size(
                 ctx->h2, stream->id),
               nghttp2_session_get_local_window_size(ctx->h2),
               HTTP2_HUGE_WINDOW_SIZE);
 
   CF_DATA_RESTORE(cf, save);
   return result;
 }
 
 static ssize_t cf_h2_body_send(struct Curl_cfilter *cf,
                                struct Curl_easy *data,
                                struct h2_stream_ctx *stream,
                                const void *buf, size_t blen, bool eos,
                                CURLcode *err)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   size_t nwritten;
 
   if(stream->closed) {
     if(stream->resp_hds_complete) {
       /* Server decided to close the stream after having sent us a final
        * response. This is valid if it is not interested in the request
        * body. This happens on 30x or 40x responses.
        * We silently discard the data sent, since this is not a transport
        * error situation. */
       CURL_TRC_CF(data, cf, "[%d] discarding data"
                   "on closed stream with response", stream->id);
       if(eos)
         stream->body_eos = TRUE;
       *err = CURLE_OK;
       return (ssize_t)blen;
     }
     /* Server closed before we got a response, this is an error */
     infof(data, "stream %u closed", stream->id);
     *err = CURLE_SEND_ERROR;
     return -1;
   }
 
   *err = Curl_bufq_write(&stream->sendbuf, buf, blen, &nwritten);
   if(*err)
     return -1;
 
   if(eos && (blen == nwritten))
     stream->body_eos = TRUE;
 
   if(eos || !Curl_bufq_is_empty(&stream->sendbuf)) {
     /* resume the potentially suspended stream */
     int rv = nghttp2_session_resume_data(ctx->h2, stream->id);
     if(nghttp2_is_fatal(rv)) {
       *err = CURLE_SEND_ERROR;
       return -1;
     }
   }
   return (ssize_t)nwritten;
 }
 
 static CURLcode h2_submit(struct h2_stream_ctx **pstream,
                           struct Curl_cfilter *cf, struct Curl_easy *data,
                           const void *buf, size_t len,
                           bool eos, size_t *pnwritten)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   struct h2_stream_ctx *stream = NULL;
   struct dynhds h2_headers;
   nghttp2_nv *nva = NULL;
   const void *body = NULL;
   size_t nheader, bodylen, i;
   nghttp2_data_provider data_prd;
   int32_t stream_id;
   nghttp2_priority_spec pri_spec;
   ssize_t nwritten;
   CURLcode result = CURLE_OK;
 
   *pnwritten = 0;
   Curl_dynhds_init(&h2_headers, 0, DYN_HTTP_REQUEST);
 
   result = http2_data_setup(cf, data, &stream);
   if(result)
     goto out;
 
   nwritten = Curl_h1_req_parse_read(&stream->h1, buf, len, NULL, 0, &result);
   if(nwritten < 0)
     goto out;
   *pnwritten = (size_t)nwritten;
   if(!stream->h1.done) {
     /* need more data */
     goto out;
   }
   DEBUGASSERT(stream->h1.req);
 
   result = Curl_http_req_to_h2(&h2_headers, stream->h1.req, data);
   if(result)
     goto out;
   /* no longer needed */
   Curl_h1_req_parse_free(&stream->h1);
 
   nva = Curl_dynhds_to_nva(&h2_headers, &nheader);
   if(!nva) {
     result = CURLE_OUT_OF_MEMORY;
     goto out;
   }
 
   h2_pri_spec(ctx, data, &pri_spec);
   if(!nghttp2_session_check_request_allowed(ctx->h2))
     CURL_TRC_CF(data, cf, "send request NOT allowed (via nghttp2)");
 
   switch(data->state.httpreq) {
   case HTTPREQ_POST:
   case HTTPREQ_POST_FORM:
   case HTTPREQ_POST_MIME:
   case HTTPREQ_PUT:
     data_prd.read_callback = req_body_read_callback;
     data_prd.source.ptr = NULL;
     stream_id = nghttp2_submit_request(ctx->h2, &pri_spec, nva, nheader,
                                        &data_prd, data);
     break;
   default:
     stream_id = nghttp2_submit_request(ctx->h2, &pri_spec, nva, nheader,
                                        NULL, data);
   }
 
   if(stream_id < 0) {
     CURL_TRC_CF(data, cf, "send: nghttp2_submit_request error (%s)%u",
                 nghttp2_strerror(stream_id), stream_id);
     result = CURLE_SEND_ERROR;
     goto out;
   }
 
 #define MAX_ACC 60000  /* <64KB to account for some overhead */
   if(Curl_trc_is_verbose(data)) {
     size_t acc = 0;
 
     infof(data, "[HTTP/2] [%d] OPENED stream for %s",
           stream_id, data->state.url);
     for(i = 0; i < nheader; ++i) {
       acc += nva[i].namelen + nva[i].valuelen;
 
       infof(data, "[HTTP/2] [%d] [%.*s: %.*s]", stream_id,
             (int)nva[i].namelen, nva[i].name,
             (int)nva[i].valuelen, nva[i].value);
     }
 
     if(acc > MAX_ACC) {
       infof(data, "[HTTP/2] Warning: The cumulative length of all "
             "headers exceeds %d bytes and that could cause the "
             "stream to be rejected.", MAX_ACC);
     }
   }
 
   stream->id = stream_id;
 
   body = (const char *)buf + *pnwritten;
   bodylen = len - *pnwritten;
 
   if(bodylen || eos) {
     ssize_t n = cf_h2_body_send(cf, data, stream, body, bodylen, eos, &result);
     if(n >= 0)
       *pnwritten += n;
     else if(result == CURLE_AGAIN)
       result = CURLE_OK;
     else {
       result = CURLE_SEND_ERROR;
     }
   }
 
 out:
   CURL_TRC_CF(data, cf, "[%d] submit -> %d, %zu",
               stream ? stream->id : -1, result, *pnwritten);
   Curl_safefree(nva);
   *pstream = stream;
   Curl_dynhds_free(&h2_headers);
   return result;
 }
 
 static CURLcode cf_h2_send(struct Curl_cfilter *cf, struct Curl_easy *data,
                            const void *buf, size_t len, bool eos,
                            size_t *pnwritten)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   struct h2_stream_ctx *stream = H2_STREAM_CTX(ctx, data);
   struct cf_call_data save;
   ssize_t nwritten;
   CURLcode result = CURLE_OK, r2;
 
   CF_DATA_SAVE(save, cf, data);
   *pnwritten = 0;
 
   if(!stream || stream->id == -1) {
     result = h2_submit(&stream, cf, data, buf, len, eos, pnwritten);
     if(result)
       goto out;
     DEBUGASSERT(stream);
   }
   else if(stream->body_eos) {
     /* We already wrote this, but CURLE_AGAINed the call due to not
      * being able to flush stream->sendbuf. Make a 0-length write
      * to trigger flushing again.
      * If this works, we report to have written `len` bytes. */
     DEBUGASSERT(eos);
     nwritten = cf_h2_body_send(cf, data, stream, buf, 0, eos, &result);
     CURL_TRC_CF(data, cf, "[%d] cf_body_send last CHUNK -> %zd, %d, eos=%d",
                 stream->id, nwritten, result, eos);
     if(nwritten < 0) {
       goto out;
     }
     *pnwritten = len;
   }
   else {
     nwritten = cf_h2_body_send(cf, data, stream, buf, len, eos, &result);
     CURL_TRC_CF(data, cf, "[%d] cf_body_send(len=%zu) -> %zd, %d, eos=%d",
                 stream->id, len, nwritten, result, eos);
     if(nwritten >= 0)
       *pnwritten = (size_t)nwritten;
   }
 
   /* Call the nghttp2 send loop and flush to write ALL buffered data,
    * headers and/or request body completely out to the network */
   r2 = h2_progress_egress(cf, data);
 
   /* if the stream has been closed in egress handling (nghttp2 does that
    * when it does not like the headers, for example */
   if(stream && stream->closed) {
     infof(data, "stream %u closed", stream->id);
     result = CURLE_SEND_ERROR;
     goto out;
   }
   else if(r2 && (r2 != CURLE_AGAIN)) {
     result = r2;
     goto out;
   }
 
   if(should_close_session(ctx)) {
     /* nghttp2 thinks this session is done. If the stream has not been
      * closed, this is an error state for out transfer */
     if(stream && stream->closed) {
       result = http2_handle_stream_close(cf, data, stream, pnwritten);
     }
     else {
       CURL_TRC_CF(data, cf, "send: nothing to do in this session");
       result = CURLE_HTTP2;
     }
   }
 
 out:
   if(stream) {
     CURL_TRC_CF(data, cf, "[%d] cf_send(len=%zu) -> %d, %zu, "
                 "eos=%d, h2 windows %d-%d (stream-conn), "
                 "buffers %zu-%zu (stream-conn)",
                 stream->id, len, result, *pnwritten,
                 stream->body_eos,
                 nghttp2_session_get_stream_remote_window_size(
                   ctx->h2, stream->id),
                 nghttp2_session_get_remote_window_size(ctx->h2),
                 Curl_bufq_len(&stream->sendbuf),
                 Curl_bufq_len(&ctx->outbufq));
   }
   else {
     CURL_TRC_CF(data, cf, "cf_send(len=%zu) -> %d, %zu, "
                 "connection-window=%d, nw_send_buffer(%zu)",
                 len, result, *pnwritten,
                 nghttp2_session_get_remote_window_size(ctx->h2),
                 Curl_bufq_len(&ctx->outbufq));
   }
   CF_DATA_RESTORE(cf, save);
   return result;
 }
 
 static CURLcode cf_h2_flush(struct Curl_cfilter *cf,
                             struct Curl_easy *data)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   struct h2_stream_ctx *stream = H2_STREAM_CTX(ctx, data);
   struct cf_call_data save;
   CURLcode result = CURLE_OK;
 
   CF_DATA_SAVE(save, cf, data);
   if(stream && !Curl_bufq_is_empty(&stream->sendbuf)) {
     /* resume the potentially suspended stream */
     int rv = nghttp2_session_resume_data(ctx->h2, stream->id);
     if(nghttp2_is_fatal(rv)) {
       result = CURLE_SEND_ERROR;
       goto out;
     }
   }
 
   result = h2_progress_egress(cf, data);
 
 out:
   if(stream) {
     CURL_TRC_CF(data, cf, "[%d] flush -> %d, "
                 "h2 windows %d-%d (stream-conn), "
                 "buffers %zu-%zu (stream-conn)",
                 stream->id, result,
                 nghttp2_session_get_stream_remote_window_size(
                   ctx->h2, stream->id),
                 nghttp2_session_get_remote_window_size(ctx->h2),
                 Curl_bufq_len(&stream->sendbuf),
                 Curl_bufq_len(&ctx->outbufq));
   }
   else {
     CURL_TRC_CF(data, cf, "flush -> %d, "
                 "connection-window=%d, nw_send_buffer(%zu)",
                 result, nghttp2_session_get_remote_window_size(ctx->h2),
                 Curl_bufq_len(&ctx->outbufq));
   }
   CF_DATA_RESTORE(cf, save);
   return result;
 }
 
 static void cf_h2_adjust_pollset(struct Curl_cfilter *cf,
                                  struct Curl_easy *data,
                                  struct easy_pollset *ps)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   struct cf_call_data save;
   curl_socket_t sock;
   bool want_recv, want_send;
 
   if(!ctx->h2)
     return;
 
   sock = Curl_conn_cf_get_socket(cf, data);
   Curl_pollset_check(data, ps, sock, &want_recv, &want_send);
   if(want_recv || want_send) {
     struct h2_stream_ctx *stream = H2_STREAM_CTX(ctx, data);
     bool c_exhaust, s_exhaust;
 
     CF_DATA_SAVE(save, cf, data);
     c_exhaust = want_send && !nghttp2_session_get_remote_window_size(ctx->h2);
     s_exhaust = want_send && stream && stream->id >= 0 &&
                 !nghttp2_session_get_stream_remote_window_size(ctx->h2,
                                                                stream->id);
     want_recv = (want_recv || c_exhaust || s_exhaust);
     want_send = (!s_exhaust && want_send) ||
                 (!c_exhaust && nghttp2_session_want_write(ctx->h2)) ||
                 !Curl_bufq_is_empty(&ctx->outbufq);
 
     Curl_pollset_set(data, ps, sock, want_recv, want_send);
     CF_DATA_RESTORE(cf, save);
   }
   else if(ctx->sent_goaway && !cf->shutdown) {
     /* shutdown in progress */
     CF_DATA_SAVE(save, cf, data);
     want_send = nghttp2_session_want_write(ctx->h2) ||
                 !Curl_bufq_is_empty(&ctx->outbufq);
     want_recv = nghttp2_session_want_read(ctx->h2);
     Curl_pollset_set(data, ps, sock, want_recv, want_send);
     CF_DATA_RESTORE(cf, save);
   }
 }
 
 static CURLcode cf_h2_connect(struct Curl_cfilter *cf,
                               struct Curl_easy *data,
                               bool *done)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   CURLcode result = CURLE_OK;
   struct cf_call_data save;
   bool first_time = FALSE;
 
   if(cf->connected) {
     *done = TRUE;
     return CURLE_OK;
   }
 
   /* Connect the lower filters first */
   if(!cf->next->connected) {
     result = Curl_conn_cf_connect(cf->next, data, done);
     if(result || !*done)
       return result;
   }
 
   *done = FALSE;
 
   CF_DATA_SAVE(save, cf, data);
   DEBUGASSERT(ctx->initialized);
   if(!ctx->h2) {
     result = cf_h2_ctx_open(cf, data);
     if(result)
       goto out;
     first_time = TRUE;
   }
 
   if(!first_time) {
     result = h2_progress_ingress(cf, data, H2_CHUNK_SIZE);
     if(result)
       goto out;
   }
 
   /* Send out our SETTINGS and ACKs and such. If that blocks, we
    * have it buffered and  can count this filter as being connected */
   result = h2_progress_egress(cf, data);
   if(result && (result != CURLE_AGAIN))
     goto out;
 
   *done = TRUE;
   cf->connected = TRUE;
   result = CURLE_OK;
 
 out:
   CURL_TRC_CF(data, cf, "cf_connect() -> %d, %d, ", result, *done);
   CF_DATA_RESTORE(cf, save);
   return result;
 }
 
 static void cf_h2_close(struct Curl_cfilter *cf, struct Curl_easy *data)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
 
   if(ctx) {
     struct cf_call_data save;
 
     CF_DATA_SAVE(save, cf, data);
     cf_h2_ctx_close(ctx);
     CF_DATA_RESTORE(cf, save);
     cf->connected = FALSE;
   }
   if(cf->next)
     cf->next->cft->do_close(cf->next, data);
 }
 
 static void cf_h2_destroy(struct Curl_cfilter *cf, struct Curl_easy *data)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
 
   (void)data;
   if(ctx) {
     cf_h2_ctx_free(ctx);
     cf->ctx = NULL;
   }
 }
 
 static CURLcode cf_h2_shutdown(struct Curl_cfilter *cf,
                                struct Curl_easy *data, bool *done)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   struct cf_call_data save;
   CURLcode result;
   int rv;
 
   if(!cf->connected || !ctx->h2 || cf->shutdown || ctx->conn_closed) {
     *done = TRUE;
     return CURLE_OK;
   }
 
   CF_DATA_SAVE(save, cf, data);
 
   if(!ctx->sent_goaway) {
     ctx->sent_goaway = TRUE;
     rv = nghttp2_submit_goaway(ctx->h2, NGHTTP2_FLAG_NONE,
                                ctx->local_max_sid, 0,
                                (const uint8_t *)"shutdown",
                                sizeof("shutdown"));
     if(rv) {
       failf(data, "nghttp2_submit_goaway() failed: %s(%d)",
             nghttp2_strerror(rv), rv);
       result = CURLE_SEND_ERROR;
       goto out;
     }
   }
   /* GOAWAY submitted, process egress and ingress until nghttp2 is done. */
   result = CURLE_OK;
   if(nghttp2_session_want_write(ctx->h2) ||
      !Curl_bufq_is_empty(&ctx->outbufq))
     result = h2_progress_egress(cf, data);
   if(!result && nghttp2_session_want_read(ctx->h2))
     result = h2_progress_ingress(cf, data, 0);
 
   if(result == CURLE_AGAIN)
     result = CURLE_OK;
 
   *done = (ctx->conn_closed ||
            (!result && !nghttp2_session_want_write(ctx->h2) &&
             !nghttp2_session_want_read(ctx->h2) &&
             Curl_bufq_is_empty(&ctx->outbufq)));
 
 out:
   CF_DATA_RESTORE(cf, save);
   cf->shutdown = (result || *done);
   return result;
 }
 
 static CURLcode http2_data_pause(struct Curl_cfilter *cf,
                                  struct Curl_easy *data,
                                  bool pause)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   struct h2_stream_ctx *stream = H2_STREAM_CTX(ctx, data);
 
   DEBUGASSERT(data);
   if(ctx && ctx->h2 && stream) {
     CURLcode result;
 
     stream->write_paused = pause;
     result = cf_h2_update_local_win(cf, data, stream);
     if(result)
       return result;
 
     /* attempt to send the window update */
     (void)h2_progress_egress(cf, data);
 
     if(!pause) {
       /* Unpausing a h2 transfer, requires it to be run again. The server
        * may send new DATA on us increasing the flow window, and it may
        * not. We may have already buffered and exhausted the new window
        * by operating on things in flight during the handling of other
        * transfers. */
       Curl_multi_mark_dirty(data);
     }
     CURL_TRC_CF(data, cf, "[%d] stream now %spaused", stream->id,
                 pause ? "" : "un");
   }
   return CURLE_OK;
 }
 
 static CURLcode cf_h2_cntrl(struct Curl_cfilter *cf,
                             struct Curl_easy *data,
                             int event, int arg1, void *arg2)
 {
   CURLcode result = CURLE_OK;
   struct cf_call_data save;
 
   (void)arg2;
 
   CF_DATA_SAVE(save, cf, data);
   switch(event) {
   case CF_CTRL_DATA_SETUP:
     break;
   case CF_CTRL_DATA_PAUSE:
     result = http2_data_pause(cf, data, (arg1 != 0));
     break;
   case CF_CTRL_FLUSH:
     result = cf_h2_flush(cf, data);
     break;
   case CF_CTRL_DATA_DONE:
     http2_data_done(cf, data);
     break;
   default:
     break;
   }
   CF_DATA_RESTORE(cf, save);
   return result;
 }
 
 static bool cf_h2_data_pending(struct Curl_cfilter *cf,
                                const struct Curl_easy *data)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
 
   if(ctx && !Curl_bufq_is_empty(&ctx->inbufq))
     return TRUE;
   return cf->next ? cf->next->cft->has_data_pending(cf->next, data) : FALSE;
 }
 
 static bool cf_h2_is_alive(struct Curl_cfilter *cf,
                            struct Curl_easy *data,
                            bool *input_pending)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   bool alive;
   struct cf_call_data save;
 
   *input_pending = FALSE;
   CF_DATA_SAVE(save, cf, data);
   alive = (ctx && ctx->h2 && http2_connisalive(cf, data, input_pending));
   CURL_TRC_CF(data, cf, "conn alive -> %d, input_pending=%d",
               alive, *input_pending);
   CF_DATA_RESTORE(cf, save);
   return alive;
 }
 
 static CURLcode cf_h2_keep_alive(struct Curl_cfilter *cf,
                                  struct Curl_easy *data)
 {
   CURLcode result;
   struct cf_call_data save;
 
   CF_DATA_SAVE(save, cf, data);
   result = http2_send_ping(cf, data);
   CF_DATA_RESTORE(cf, save);
   return result;
 }
 
 static CURLcode cf_h2_query(struct Curl_cfilter *cf,
                             struct Curl_easy *data,
                             int query, int *pres1, void *pres2)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   struct cf_call_data save;
   size_t effective_max;
 
   switch(query) {
   case CF_QUERY_MAX_CONCURRENT:
     DEBUGASSERT(pres1);
 
     CF_DATA_SAVE(save, cf, data);
     if(!ctx->h2 || !nghttp2_session_check_request_allowed(ctx->h2)) {
       /* the limit is what we have in use right now */
       effective_max = CONN_ATTACHED(cf->conn);
     }
     else {
       effective_max = ctx->max_concurrent_streams;
     }
     *pres1 = (effective_max > INT_MAX) ? INT_MAX : (int)effective_max;
     CF_DATA_RESTORE(cf, save);
     return CURLE_OK;
   case CF_QUERY_STREAM_ERROR: {
     struct h2_stream_ctx *stream = H2_STREAM_CTX(ctx, data);
     *pres1 = stream ? (int)stream->error : 0;
     return CURLE_OK;
   }
   case CF_QUERY_NEED_FLUSH: {
     struct h2_stream_ctx *stream = H2_STREAM_CTX(ctx, data);
     if(!Curl_bufq_is_empty(&ctx->outbufq) ||
        (stream && !Curl_bufq_is_empty(&stream->sendbuf))) {
       *pres1 = TRUE;
       return CURLE_OK;
     }
     break;
   }
   case CF_QUERY_HTTP_VERSION:
     *pres1 = 20;
     return CURLE_OK;
   default:
     break;
   }
   return cf->next ?
     cf->next->cft->query(cf->next, data, query, pres1, pres2) :
     CURLE_UNKNOWN_OPTION;
 }
 
 struct Curl_cftype Curl_cft_nghttp2 = {
   "HTTP/2",
   CF_TYPE_MULTIPLEX | CF_TYPE_HTTP,
   CURL_LOG_LVL_NONE,
   cf_h2_destroy,
   cf_h2_connect,
   cf_h2_close,
   cf_h2_shutdown,
   cf_h2_adjust_pollset,
   cf_h2_data_pending,
   cf_h2_send,
   cf_h2_recv,
   cf_h2_cntrl,
   cf_h2_is_alive,
   cf_h2_keep_alive,
   cf_h2_query,
 };
 
 static CURLcode http2_cfilter_add(struct Curl_cfilter **pcf,
                                   struct Curl_easy *data,
                                   struct connectdata *conn,
                                   int sockindex,
                                   bool via_h1_upgrade)
 {
   struct Curl_cfilter *cf = NULL;
   struct cf_h2_ctx *ctx;
   CURLcode result = CURLE_OUT_OF_MEMORY;
 
   DEBUGASSERT(data->conn);
   ctx = calloc(1, sizeof(*ctx));
   if(!ctx)
     goto out;
   cf_h2_ctx_init(ctx, via_h1_upgrade);
 
   result = Curl_cf_create(&cf, &Curl_cft_nghttp2, ctx);
   if(result)
     goto out;
 
   ctx = NULL;
   Curl_conn_cf_add(data, conn, sockindex, cf);
 
 out:
   if(result)
     cf_h2_ctx_free(ctx);
   *pcf = result ? NULL : cf;
   return result;
 }
 
 static CURLcode http2_cfilter_insert_after(struct Curl_cfilter *cf,
                                            struct Curl_easy *data,
                                            bool via_h1_upgrade)
 {
   struct Curl_cfilter *cf_h2 = NULL;
   struct cf_h2_ctx *ctx;
   CURLcode result = CURLE_OUT_OF_MEMORY;
 
   (void)data;
   ctx = calloc(1, sizeof(*ctx));
   if(!ctx)
     goto out;
   cf_h2_ctx_init(ctx, via_h1_upgrade);
 
   result = Curl_cf_create(&cf_h2, &Curl_cft_nghttp2, ctx);
   if(result)
     goto out;
 
   ctx = NULL;
   Curl_conn_cf_insert_after(cf, cf_h2);
 
 out:
   if(result)
     cf_h2_ctx_free(ctx);
   return result;
 }
 
 bool Curl_http2_may_switch(struct Curl_easy *data)
 {
   if(Curl_conn_http_version(data, data->conn) < 20 &&
      (data->state.http_neg.wanted & CURL_HTTP_V2x) &&
      data->state.http_neg.h2_prior_knowledge) {
 #ifndef CURL_DISABLE_PROXY
     if(data->conn->bits.httpproxy && !data->conn->bits.tunnel_proxy) {
       /* We do not support HTTP/2 proxies yet. Also it is debatable
          whether or not this setting should apply to HTTP/2 proxies. */
       infof(data, "Ignoring HTTP/2 prior knowledge due to proxy");
       return FALSE;
     }
 #endif
     return TRUE;
   }
   return FALSE;
 }
 
 CURLcode Curl_http2_switch(struct Curl_easy *data)
 {
   struct Curl_cfilter *cf;
   CURLcode result;
 
   DEBUGASSERT(Curl_conn_http_version(data, data->conn) < 20);
 
   result = http2_cfilter_add(&cf, data, data->conn, FIRSTSOCKET, FALSE);
   if(result)
     return result;
   CURL_TRC_CF(data, cf, "switching connection to HTTP/2");
 
   data->conn->bits.multiplex = TRUE; /* at least potentially multiplexed */
   Curl_multi_connchanged(data->multi);
 
   if(cf->next) {
     bool done;
     return Curl_conn_cf_connect(cf, data, &done);
   }
   return CURLE_OK;
 }
 
 CURLcode Curl_http2_switch_at(struct Curl_cfilter *cf, struct Curl_easy *data)
 {
   struct Curl_cfilter *cf_h2;
   CURLcode result;
 
   DEBUGASSERT(Curl_conn_http_version(data, data->conn) < 20);
 
   result = http2_cfilter_insert_after(cf, data, FALSE);
   if(result)
     return result;
 
   cf_h2 = cf->next;
   cf->conn->bits.multiplex = TRUE; /* at least potentially multiplexed */
   Curl_multi_connchanged(data->multi);
 
   if(cf_h2->next) {
     bool done;
     return Curl_conn_cf_connect(cf_h2, data, &done);
   }
   return CURLE_OK;
 }
 
 CURLcode Curl_http2_upgrade(struct Curl_easy *data,
                             struct connectdata *conn, int sockindex,
                             const char *mem, size_t nread)
 {
   struct Curl_cfilter *cf;
   struct cf_h2_ctx *ctx;
   CURLcode result;
 
   DEBUGASSERT(Curl_conn_http_version(data, conn) <  20);
   DEBUGASSERT(data->req.upgr101 == UPGR101_RECEIVED);
 
   result = http2_cfilter_add(&cf, data, conn, sockindex, TRUE);
   if(result)
     return result;
   CURL_TRC_CF(data, cf, "upgrading connection to HTTP/2");
 
   DEBUGASSERT(cf->cft == &Curl_cft_nghttp2);
   ctx = cf->ctx;
 
   if(nread > 0) {
     /* Remaining data from the protocol switch reply is already using
      * the switched protocol, ie. HTTP/2. We add that to the network
      * inbufq. */
     size_t copied;
 
     result = Curl_bufq_write(&ctx->inbufq,
                              (const unsigned char *)mem, nread, &copied);
     if(result) {
       failf(data, "error on copying HTTP Upgrade response: %d", result);
       return CURLE_RECV_ERROR;
     }
     if(copied < nread) {
       failf(data, "connection buffer size could not take all data "
             "from HTTP Upgrade response header: copied=%zu, datalen=%zu",
             copied, nread);
       return CURLE_HTTP2;
     }
     infof(data, "Copied HTTP/2 data in stream buffer to connection buffer"
           " after upgrade: len=%zu", nread);
   }
 
   conn->bits.multiplex = TRUE; /* at least potentially multiplexed */
   Curl_multi_connchanged(data->multi);
 
   if(cf->next) {
     bool done;
     return Curl_conn_cf_connect(cf, data, &done);
   }
   return CURLE_OK;
 }
 
 /* Only call this function for a transfer that already got an HTTP/2
    CURLE_HTTP2_STREAM error! */
 bool Curl_h2_http_1_1_error(struct Curl_easy *data)
 {
   if(Curl_conn_http_version(data, data->conn) == 20) {
     int err = Curl_conn_get_stream_error(data, data->conn, FIRSTSOCKET);
     return err == NGHTTP2_HTTP_1_1_REQUIRED;
   }
   return FALSE;
 }
 
 void *Curl_nghttp2_malloc(size_t size, void *user_data)
 {
   (void)user_data;
   return Curl_cmalloc(size);
 }
 
 void Curl_nghttp2_free(void *ptr, void *user_data)
 {
   (void)user_data;
   Curl_cfree(ptr);
 }
 
 void *Curl_nghttp2_calloc(size_t nmemb, size_t size, void *user_data)
 {
   (void)user_data;
   return Curl_ccalloc(nmemb, size);
 }
 
 void *Curl_nghttp2_realloc(void *ptr, size_t size, void *user_data)
 {
   (void)user_data;
   return Curl_crealloc(ptr, size);
 }
 
 #else /* !USE_NGHTTP2 */
 
 /* Satisfy external references even if http2 is not compiled in. */
 #include <curl/curl.h>
 
 char *curl_pushheader_bynum(struct curl_pushheaders *h, size_t num)
 {
   (void) h;
   (void) num;
   return NULL;
 }
 
 char *curl_pushheader_byname(struct curl_pushheaders *h, const char *header)
 {
   (void) h;
   (void) header;
   return NULL;
 }
 
 #endif /* USE_NGHTTP2 */