aboutsummaryrefslogtreecommitdiffstats
path: root/external/libcurl_android/jni/libcurl/lib/http2.c
blob: 604514d71c7c090da40d64ec8dc22338bd0e544f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2014, 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 http://curl.haxx.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.
 *
 ***************************************************************************/

#include "curl_setup.h"

#ifdef USE_NGHTTP2
#define _MPRINTF_REPLACE
#include <curl/mprintf.h>

#include <nghttp2/nghttp2.h>
#include "urldata.h"
#include "http2.h"
#include "http.h"
#include "sendf.h"
#include "curl_base64.h"
#include "curl_memory.h"
#include "rawstr.h"
#include "multiif.h"

/* include memdebug.h last */
#include "memdebug.h"

#if (NGHTTP2_VERSION_NUM < 0x000600)
#error too old nghttp2 version, upgrade!
#endif

static int http2_perform_getsock(const struct connectdata *conn,
                                 curl_socket_t *sock, /* points to
                                                         numsocks
                                                         number of
                                                         sockets */
                                 int numsocks)
{
  const struct http_conn *httpc = &conn->proto.httpc;
  int bitmap = GETSOCK_BLANK;
  (void)numsocks;

  /* TODO We should check underlying socket state if it is SSL socket
     because of renegotiation. */
  sock[0] = conn->sock[FIRSTSOCKET];

  if(nghttp2_session_want_read(httpc->h2))
    bitmap |= GETSOCK_READSOCK(FIRSTSOCKET);

  if(nghttp2_session_want_write(httpc->h2))
    bitmap |= GETSOCK_WRITESOCK(FIRSTSOCKET);

  return bitmap;
}

static int http2_getsock(struct connectdata *conn,
                         curl_socket_t *sock, /* points to numsocks
                                                 number of sockets */
                         int numsocks)
{
  return http2_perform_getsock(conn, sock, numsocks);
}

static CURLcode http2_disconnect(struct connectdata *conn,
                                 bool dead_connection)
{
  struct http_conn *httpc = &conn->proto.httpc;
  (void)dead_connection;

  infof(conn->data, "HTTP/2 DISCONNECT starts now\n");

  nghttp2_session_del(httpc->h2);

  Curl_safefree(httpc->header_recvbuf->buffer);
  Curl_safefree(httpc->header_recvbuf);

  Curl_safefree(httpc->inbuf);

  infof(conn->data, "HTTP/2 DISCONNECT done\n");

  return CURLE_OK;
}

/*
 * HTTP2 handler interface. This isn't added to the general list of protocols
 * but will be used at run-time when the protocol is dynamically switched from
 * HTTP to HTTP2.
 */
const struct Curl_handler Curl_handler_http2 = {
  "HTTP2",                              /* scheme */
  ZERO_NULL,                            /* setup_connection */
  Curl_http,                            /* do_it */
  ZERO_NULL,                            /* done */
  ZERO_NULL,                            /* do_more */
  ZERO_NULL,                            /* connect_it */
  ZERO_NULL,                            /* connecting */
  ZERO_NULL,                            /* doing */
  http2_getsock,                        /* proto_getsock */
  http2_getsock,                        /* doing_getsock */
  ZERO_NULL,                            /* domore_getsock */
  http2_perform_getsock,                /* perform_getsock */
  http2_disconnect,                     /* disconnect */
  ZERO_NULL,                            /* readwrite */
  PORT_HTTP,                            /* defport */
  CURLPROTO_HTTP,                       /* protocol */
  PROTOPT_NONE                          /* flags */
};

const struct Curl_handler Curl_handler_http2_ssl = {
  "HTTP2",                              /* scheme */
  ZERO_NULL,                            /* setup_connection */
  Curl_http,                            /* do_it */
  ZERO_NULL,                            /* done */
  ZERO_NULL,                            /* do_more */
  ZERO_NULL,                            /* connect_it */
  ZERO_NULL,                            /* connecting */
  ZERO_NULL,                            /* doing */
  http2_getsock,                        /* proto_getsock */
  http2_getsock,                        /* doing_getsock */
  ZERO_NULL,                            /* domore_getsock */
  http2_perform_getsock,                /* perform_getsock */
  http2_disconnect,                     /* disconnect */
  ZERO_NULL,                            /* readwrite */
  PORT_HTTP,                            /* defport */
  CURLPROTO_HTTPS,                      /* protocol */
  PROTOPT_SSL                           /* flags */
};

/*
 * Store nghttp2 version info in this buffer, Prefix with a space.  Return
 * total length written.
 */
int Curl_http2_ver(char *p, size_t len)
{
  nghttp2_info *h2 = nghttp2_version(0);
  return snprintf(p, len, " nghttp2/%s", h2->version_str);
}

/*
 * 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 *data, size_t length, int flags,
                             void *userp)
{
  struct connectdata *conn = (struct connectdata *)userp;
  struct http_conn *httpc = &conn->proto.httpc;
  ssize_t written;
  CURLcode rc;
  (void)h2;
  (void)flags;

  rc = 0;
  written = ((Curl_send*)httpc->send_underlying)(conn, FIRSTSOCKET,
                                                 data, length, &rc);

  if(rc == CURLE_AGAIN) {
    return NGHTTP2_ERR_WOULDBLOCK;
  }

  if(written == -1) {
    failf(conn->data, "Failed sending HTTP2 data");
    return NGHTTP2_ERR_CALLBACK_FAILURE;
  }

  if(!written)
    return NGHTTP2_ERR_WOULDBLOCK;

  return written;
}

static int on_frame_recv(nghttp2_session *session, const nghttp2_frame *frame,
                         void *userp)
{
  struct connectdata *conn = (struct connectdata *)userp;
  struct http_conn *c = &conn->proto.httpc;
  int rv;
  size_t left, ncopy;

  (void)session;
  (void)frame;
  infof(conn->data, "on_frame_recv() was called with header %x\n",
        frame->hd.type);
  switch(frame->hd.type) {
  case NGHTTP2_DATA:
    /* If body started, then receiving DATA is illegal. */
    if(!c->bodystarted) {
      rv = nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE,
                                     frame->hd.stream_id,
                                     NGHTTP2_PROTOCOL_ERROR);

      if(nghttp2_is_fatal(rv)) {
        return NGHTTP2_ERR_CALLBACK_FAILURE;
      }
    }
    break;
  case NGHTTP2_HEADERS:
    if(frame->headers.cat == NGHTTP2_HCAT_REQUEST)
      break;

    if(c->bodystarted) {
      /* Only valid HEADERS after body started is trailer header,
         which is not fully supported in this code.  If HEADERS is not
         trailer, then it is a PROTOCOL_ERROR. */
      if((frame->hd.flags & NGHTTP2_FLAG_END_STREAM) == 0) {
        rv = nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE,
                                       frame->hd.stream_id,
                                       NGHTTP2_PROTOCOL_ERROR);

        if(nghttp2_is_fatal(rv)) {
          return NGHTTP2_ERR_CALLBACK_FAILURE;
        }
      }
      break;
    }

    if(c->status_code == -1) {
      /* No :status header field means PROTOCOL_ERROR. */
      rv = nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE,
                                     frame->hd.stream_id,
                                     NGHTTP2_PROTOCOL_ERROR);

      if(nghttp2_is_fatal(rv)) {
        return NGHTTP2_ERR_CALLBACK_FAILURE;
      }

      break;
    }

    /* Only final status code signals the end of header */
    if(c->status_code / 100 != 1) {
      c->bodystarted = TRUE;
    }

    c->status_code = -1;

    Curl_add_buffer(c->header_recvbuf, "\r\n", 2);

    left = c->header_recvbuf->size_used - c->nread_header_recvbuf;
    ncopy = c->len < left ? c->len : left;

    memcpy(c->mem, c->header_recvbuf->buffer + c->nread_header_recvbuf, ncopy);
    c->nread_header_recvbuf += ncopy;

    c->mem += ncopy;
    c->len -= ncopy;
    break;
  case NGHTTP2_PUSH_PROMISE:
    rv = nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE,
                                   frame->push_promise.promised_stream_id,
                                   NGHTTP2_CANCEL);
    if(nghttp2_is_fatal(rv)) {
      return rv;
    }
    break;
  }
  return 0;
}

static int on_invalid_frame_recv(nghttp2_session *session,
                                 const nghttp2_frame *frame,
                                 uint32_t error_code, void *userp)
{
  struct connectdata *conn = (struct connectdata *)userp;
  (void)session;
  (void)frame;
  infof(conn->data, "on_invalid_frame_recv() was called, error_code = %d\n",
        error_code);
  return 0;
}

static int on_data_chunk_recv(nghttp2_session *session, uint8_t flags,
                              int32_t stream_id,
                              const uint8_t *data, size_t len, void *userp)
{
  struct connectdata *conn = (struct connectdata *)userp;
  struct http_conn *c = &conn->proto.httpc;
  size_t nread;
  (void)session;
  (void)flags;
  (void)data;
  infof(conn->data, "on_data_chunk_recv() "
        "len = %u, stream = %x\n", len, stream_id);

  if(stream_id != c->stream_id) {
    return 0;
  }

  nread = c->len < len ? c->len : len;
  memcpy(c->mem, data, nread);

  c->mem += nread;
  c->len -= nread;

  infof(conn->data, "%zu data written\n", nread);

  if(nread < len) {
    c->data = data + nread;
    c->datalen = len - nread;
    return NGHTTP2_ERR_PAUSE;
  }
  return 0;
}

static int before_frame_send(nghttp2_session *session,
                             const nghttp2_frame *frame,
                             void *userp)
{
  struct connectdata *conn = (struct connectdata *)userp;
  (void)session;
  (void)frame;
  infof(conn->data, "before_frame_send() was called\n");
  return 0;
}
static int on_frame_send(nghttp2_session *session,
                         const nghttp2_frame *frame,
                         void *userp)
{
  struct connectdata *conn = (struct connectdata *)userp;
  (void)session;
  (void)frame;
  infof(conn->data, "on_frame_send() was called\n");
  return 0;
}
static int on_frame_not_send(nghttp2_session *session,
                             const nghttp2_frame *frame,
                             int lib_error_code, void *userp)
{
  struct connectdata *conn = (struct connectdata *)userp;
  (void)session;
  (void)frame;
  infof(conn->data, "on_frame_not_send() was called, lib_error_code = %d\n",
        lib_error_code);
  return 0;
}
static int on_stream_close(nghttp2_session *session, int32_t stream_id,
                           uint32_t error_code, void *userp)
{
  struct connectdata *conn = (struct connectdata *)userp;
  struct http_conn *c = &conn->proto.httpc;
  (void)session;
  (void)stream_id;
  infof(conn->data, "on_stream_close() was called, error_code = %d\n",
        error_code);

  if(stream_id != c->stream_id) {
    return 0;
  }

  c->closed = TRUE;

  return 0;
}

static int on_begin_headers(nghttp2_session *session,
                            const nghttp2_frame *frame, void *userp)
{
  struct connectdata *conn = (struct connectdata *)userp;
  (void)session;
  (void)frame;
  infof(conn->data, "on_begin_headers() was called\n");
  return 0;
}

/* Decode HTTP status code.  Returns -1 if no valid status code was
   decoded. */
static int decode_status_code(const uint8_t *value, size_t len)
{
  int i;
  int res;

  if(len != 3) {
    return -1;
  }

  res = 0;

  for(i = 0; i < 3; ++i) {
    char c = value[i];

    if(c < '0' || c > '9') {
      return -1;
    }

    res *= 10;
    res += c - '0';
  }

  return res;
}

static const char STATUS[] = ":status";

/* 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 connectdata *conn = (struct connectdata *)userp;
  struct http_conn *c = &conn->proto.httpc;
  int rv;
  int goodname;
  int goodheader;

  (void)session;
  (void)frame;
  (void)flags;

  if(frame->hd.stream_id != c->stream_id) {
    return 0;
  }

  if(c->bodystarted) {
    /* Ignore trailer or HEADERS not mapped to HTTP semantics.  The
       consequence is handled in on_frame_recv(). */
    return 0;
  }

  goodname = nghttp2_check_header_name(name, namelen);
  goodheader = nghttp2_check_header_value(value, valuelen);

  if(!goodname || !goodheader) {

    infof(conn->data, "Detected bad incoming header %s%s, reset stream!\n",
          goodname?"":"name",
          goodheader?"":"value");

    rv = nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE,
                                   frame->hd.stream_id,
                                   NGHTTP2_PROTOCOL_ERROR);

    if(nghttp2_is_fatal(rv)) {
      return NGHTTP2_ERR_CALLBACK_FAILURE;
    }

    return NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE;
  }

  if(namelen == sizeof(":status") - 1 &&
     memcmp(STATUS, name, namelen) == 0) {

    /* :status must appear exactly once. */
    if(c->status_code != -1 ||
       (c->status_code = decode_status_code(value, valuelen)) == -1) {

      rv = nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE,
                                     frame->hd.stream_id,
                                     NGHTTP2_PROTOCOL_ERROR);
      if(nghttp2_is_fatal(rv)) {
        return NGHTTP2_ERR_CALLBACK_FAILURE;
      }

      return NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE;
    }

    Curl_add_buffer(c->header_recvbuf, "HTTP/2.0 ", 9);
    Curl_add_buffer(c->header_recvbuf, value, valuelen);
    Curl_add_buffer(c->header_recvbuf, "\r\n", 2);

    return 0;
  }
  else {
    /* Here we are sure that namelen > 0 because of
       nghttp2_check_header_name().  Pseudo header other than :status
       is illegal. */
    if(c->status_code == -1 || name[0] == ':') {
      rv = nghttp2_submit_rst_stream(session, NGHTTP2_FLAG_NONE,
                                     frame->hd.stream_id,
                                     NGHTTP2_PROTOCOL_ERROR);
      if(nghttp2_is_fatal(rv)) {
        return NGHTTP2_ERR_CALLBACK_FAILURE;
      }

      return NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE;
    }

    /* convert to a HTTP1-style header */
    Curl_add_buffer(c->header_recvbuf, name, namelen);
    Curl_add_buffer(c->header_recvbuf, ":", 1);
    Curl_add_buffer(c->header_recvbuf, value, valuelen);
    Curl_add_buffer(c->header_recvbuf, "\r\n", 2);

    infof(conn->data, "got http2 header: %.*s: %.*s\n",
          namelen, name, valuelen, value);
  }

  return 0; /* 0 is successful */
}

static ssize_t data_source_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 connectdata *conn = (struct connectdata *)userp;
  struct http_conn *c = &conn->proto.httpc;
  size_t nread;
  (void)session;
  (void)stream_id;
  (void)source;

  nread = c->upload_len < length ? c->upload_len : length;
  if(nread > 0) {
    memcpy(buf, c->upload_mem, nread);
    c->upload_mem += nread;
    c->upload_len -= nread;
    c->upload_left -= nread;
  }

  if(c->upload_left == 0)
    *data_flags = 1;
  else if(nread == 0)
    return NGHTTP2_ERR_DEFERRED;

  return nread;
}

/*
 * The HTTP2 settings we send in the Upgrade request
 */
static nghttp2_settings_entry settings[] = {
  { NGHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS, 100 },
  { NGHTTP2_SETTINGS_INITIAL_WINDOW_SIZE, NGHTTP2_INITIAL_WINDOW_SIZE },
};

#define H2_BUFSIZE 4096

/*
 * Initialize nghttp2 for a Curl connection
 */
CURLcode Curl_http2_init(struct connectdata *conn)
{
  if(!conn->proto.httpc.h2) {
    int rc;
    nghttp2_session_callbacks *callbacks;

    conn->proto.httpc.inbuf = malloc(H2_BUFSIZE);
    if(conn->proto.httpc.inbuf == NULL)
      return CURLE_OUT_OF_MEMORY;

    rc = nghttp2_session_callbacks_new(&callbacks);

    if(rc) {
      failf(conn->data, "Couldn't initialize nghttp2 callbacks!");
      return CURLE_OUT_OF_MEMORY; /* most likely at least */
    }

    /* nghttp2_send_callback */
    nghttp2_session_callbacks_set_send_callback(callbacks, send_callback);
    /* nghttp2_on_frame_recv_callback */
    nghttp2_session_callbacks_set_on_frame_recv_callback
      (callbacks, on_frame_recv);
    /* nghttp2_on_invalid_frame_recv_callback */
    nghttp2_session_callbacks_set_on_invalid_frame_recv_callback
      (callbacks, on_invalid_frame_recv);
    /* nghttp2_on_data_chunk_recv_callback */
    nghttp2_session_callbacks_set_on_data_chunk_recv_callback
      (callbacks, on_data_chunk_recv);
    /* nghttp2_before_frame_send_callback */
    nghttp2_session_callbacks_set_before_frame_send_callback
      (callbacks, before_frame_send);
    /* nghttp2_on_frame_send_callback */
    nghttp2_session_callbacks_set_on_frame_send_callback
      (callbacks, on_frame_send);
    /* nghttp2_on_frame_not_send_callback */
    nghttp2_session_callbacks_set_on_frame_not_send_callback
      (callbacks, on_frame_not_send);
    /* nghttp2_on_stream_close_callback */
    nghttp2_session_callbacks_set_on_stream_close_callback
      (callbacks, on_stream_close);
    /* nghttp2_on_begin_headers_callback */
    nghttp2_session_callbacks_set_on_begin_headers_callback
      (callbacks, on_begin_headers);
    /* nghttp2_on_header_callback */
    nghttp2_session_callbacks_set_on_header_callback(callbacks, on_header);

    /* The nghttp2 session is not yet setup, do it */
    rc = nghttp2_session_client_new(&conn->proto.httpc.h2,
                                    callbacks, conn);

    nghttp2_session_callbacks_del(callbacks);

    if(rc) {
      failf(conn->data, "Couldn't initialize nghttp2!");
      return CURLE_OUT_OF_MEMORY; /* most likely at least */
    }
  }
  return CURLE_OK;
}

/*
 * Send a request using http2
 */
CURLcode Curl_http2_send_request(struct connectdata *conn)
{
  (void)conn;
  return CURLE_OK;
}

/*
 * Append headers to ask for a HTTP1.1 to HTTP2 upgrade.
 */
CURLcode Curl_http2_request_upgrade(Curl_send_buffer *req,
                                    struct connectdata *conn)
{
  CURLcode result;
  ssize_t binlen;
  char *base64;
  size_t blen;
  struct SingleRequest *k = &conn->data->req;
  uint8_t *binsettings = conn->proto.httpc.binsettings;

  result = Curl_http2_init(conn);
  if(result)
    return result;

  result = Curl_http2_setup(conn);
  if(result)
    return result;

  /* As long as we have a fixed set of settings, we don't have to dynamically
   * figure out the base64 strings since it'll always be the same. However,
   * the settings will likely not be fixed every time in the future.
   */

  /* this returns number of bytes it wrote */
  binlen = nghttp2_pack_settings_payload(binsettings, H2_BINSETTINGS_LEN,
                                         settings,
                                         sizeof(settings)/sizeof(settings[0]));
  if(!binlen) {
    failf(conn->data, "nghttp2 unexpectedly failed on pack_settings_payload");
    return CURLE_FAILED_INIT;
  }
  conn->proto.httpc.binlen = binlen;

  result = Curl_base64url_encode(conn->data, (const char *)binsettings, binlen,
                                 &base64, &blen);
  if(result)
    return result;

  result = Curl_add_bufferf(req,
                            "Connection: Upgrade, HTTP2-Settings\r\n"
                            "Upgrade: %s\r\n"
                            "HTTP2-Settings: %s\r\n",
                            NGHTTP2_CLEARTEXT_PROTO_VERSION_ID, base64);
  Curl_safefree(base64);

  k->upgr101 = UPGR101_REQUESTED;

  return result;
}

/*
 * If the read would block (EWOULDBLOCK) we return -1. Otherwise we return
 * a regular CURLcode value.
 */
static ssize_t http2_recv(struct connectdata *conn, int sockindex,
                          char *mem, size_t len, CURLcode *err)
{
  CURLcode rc;
  ssize_t rv;
  ssize_t nread;
  struct http_conn *httpc = &conn->proto.httpc;

  (void)sockindex; /* we always do HTTP2 on sockindex 0 */

  if(httpc->closed) {
    /* Reset to FALSE to prevent infinite loop in readwrite_data
       function. */
    httpc->closed = FALSE;
    return 0;
  }

  /* Nullify here because we call nghttp2_session_send() and they
     might refer to the old buffer. */
  httpc->upload_mem = NULL;
  httpc->upload_len = 0;

  if(httpc->bodystarted &&
     httpc->nread_header_recvbuf < httpc->header_recvbuf->size_used) {
    size_t left =
      httpc->header_recvbuf->size_used - httpc->nread_header_recvbuf;
    size_t ncopy = len < left ? len : left;
    memcpy(mem, httpc->header_recvbuf->buffer + httpc->nread_header_recvbuf,
           ncopy);
    httpc->nread_header_recvbuf += ncopy;
    return ncopy;
  }

  if(httpc->data) {
    nread = len < httpc->datalen ? len : httpc->datalen;
    memcpy(mem, httpc->data, nread);

    httpc->data += nread;
    httpc->datalen -= nread;

    infof(conn->data, "%zu data written\n", nread);
    if(httpc->datalen == 0) {
      httpc->data = NULL;
      httpc->datalen = 0;
    }
    return nread;
  }

  conn->proto.httpc.mem = mem;
  conn->proto.httpc.len = len;

  infof(conn->data, "http2_recv: %d bytes buffer\n",
        conn->proto.httpc.len);

  rc = 0;
  nread = ((Curl_recv*)httpc->recv_underlying)(conn, FIRSTSOCKET,
                                               httpc->inbuf, H2_BUFSIZE, &rc);

  if(rc == CURLE_AGAIN) {
    *err = rc;
    return -1;
  }

  if(nread == -1) {
    failf(conn->data, "Failed receiving HTTP2 data");
    *err = rc;
    return 0;
  }

  infof(conn->data, "nread=%zd\n", nread);
  rv = nghttp2_session_mem_recv(httpc->h2,
                                (const uint8_t *)httpc->inbuf, nread);

  if(nghttp2_is_fatal((int)rv)) {
    failf(conn->data, "nghttp2_session_mem_recv() returned %d:%s\n",
          rv, nghttp2_strerror((int)rv));
    *err = CURLE_RECV_ERROR;
    return 0;
  }
  infof(conn->data, "nghttp2_session_mem_recv() returns %zd\n", rv);
  /* Always send pending frames in nghttp2 session, because
     nghttp2_session_mem_recv() may queue new frame */
  rv = nghttp2_session_send(httpc->h2);
  if(rv != 0) {
    *err = CURLE_SEND_ERROR;
    return 0;
  }
  if(len != httpc->len) {
    return len - conn->proto.httpc.len;
  }
  /* If stream is closed, return 0 to signal the http routine to close
     the connection */
  if(httpc->closed) {
    /* Reset to FALSE to prevent infinite loop in readwrite_data
       function. */
    httpc->closed = FALSE;
    return 0;
  }
  *err = CURLE_AGAIN;
  return -1;
}

/* Index where :authority header field will appear in request header
   field list. */
#define AUTHORITY_DST_IDX 3

/* return number of received (decrypted) bytes */
static ssize_t http2_send(struct connectdata *conn, int sockindex,
                          const void *mem, size_t len, CURLcode *err)
{
  /*
   * BIG TODO: Currently, we send request in this function, but this
   * function is also used to send request body. It would be nice to
   * add dedicated function for request.
   */
  int rv;
  struct http_conn *httpc = &conn->proto.httpc;
  nghttp2_nv *nva;
  size_t nheader;
  size_t i;
  size_t authority_idx;
  char *hdbuf = (char*)mem;
  char *end;
  nghttp2_data_provider data_prd;
  int32_t stream_id;

  (void)sockindex;

  infof(conn->data, "http2_send len=%zu\n", len);

  if(httpc->stream_id != -1) {
    /* If stream_id != -1, we have dispatched request HEADERS, and now
       are going to send or sending request body in DATA frame */
    httpc->upload_mem = mem;
    httpc->upload_len = len;
    nghttp2_session_resume_data(httpc->h2, httpc->stream_id);
    rv = nghttp2_session_send(httpc->h2);
    if(nghttp2_is_fatal(rv)) {
      *err = CURLE_SEND_ERROR;
      return -1;
    }
    return len - httpc->upload_len;
  }

  /* Calculate number of headers contained in [mem, mem + len) */
  /* Here, we assume the curl http code generate *correct* HTTP header
     field block */
  nheader = 0;
  for(i = 0; i < len; ++i) {
    if(hdbuf[i] == 0x0a) {
      ++nheader;
    }
  }
  /* We counted additional 2 \n in the first and last line. We need 3
     new headers: :method, :path and :scheme. Therefore we need one
     more space. */
  nheader += 1;
  nva = malloc(sizeof(nghttp2_nv) * nheader);
  if(nva == NULL) {
    *err = CURLE_OUT_OF_MEMORY;
    return -1;
  }
  /* Extract :method, :path from request line */
  end = strchr(hdbuf, ' ');
  nva[0].name = (unsigned char *)":method";
  nva[0].namelen = (uint16_t)strlen((char *)nva[0].name);
  nva[0].value = (unsigned char *)hdbuf;
  nva[0].valuelen = (uint16_t)(end - hdbuf);
  nva[0].flags = NGHTTP2_NV_FLAG_NONE;

  hdbuf = end + 1;

  end = strchr(hdbuf, ' ');
  nva[1].name = (unsigned char *)":path";
  nva[1].namelen = (uint16_t)strlen((char *)nva[1].name);
  nva[1].value = (unsigned char *)hdbuf;
  nva[1].valuelen = (uint16_t)(end - hdbuf);
  nva[1].flags = NGHTTP2_NV_FLAG_NONE;

  nva[2].name = (unsigned char *)":scheme";
  nva[2].namelen = (uint16_t)strlen((char *)nva[2].name);
  if(conn->handler->flags & PROTOPT_SSL)
    nva[2].value = (unsigned char *)"https";
  else
    nva[2].value = (unsigned char *)"http";
  nva[2].valuelen = (uint16_t)strlen((char *)nva[2].value);
  nva[2].flags = NGHTTP2_NV_FLAG_NONE;

  hdbuf = strchr(hdbuf, 0x0a);
  ++hdbuf;

  authority_idx = 0;

  for(i = 3; i < nheader; ++i) {
    end = strchr(hdbuf, ':');
    assert(end);
    if(end - hdbuf == 4 && Curl_raw_nequal("host", hdbuf, 4)) {
      authority_idx = i;
      nva[i].name = (unsigned char *)":authority";
      nva[i].namelen = (uint16_t)strlen((char *)nva[i].name);
    }
    else {
      nva[i].name = (unsigned char *)hdbuf;
      nva[i].namelen = (uint16_t)(end - hdbuf);
    }
    hdbuf = end + 1;
    for(; *hdbuf == ' '; ++hdbuf);
    end = strchr(hdbuf, 0x0d);
    assert(end);
    nva[i].value = (unsigned char *)hdbuf;
    nva[i].valuelen = (uint16_t)(end - hdbuf);
    nva[i].flags = NGHTTP2_NV_FLAG_NONE;

    hdbuf = end + 2;
    /* Inspect Content-Length header field and retrieve the request
       entity length so that we can set END_STREAM to the last DATA
       frame. */
    if(nva[i].namelen == 14 &&
       Curl_raw_nequal("content-length", (char*)nva[i].name, 14)) {
      size_t j;
      for(j = 0; j < nva[i].valuelen; ++j) {
        httpc->upload_left *= 10;
        httpc->upload_left += nva[i].value[j] - '0';
      }
      infof(conn->data, "request content-length=%zu\n", httpc->upload_left);
    }
  }

  /* :authority must come before non-pseudo header fields */
  if(authority_idx != 0 && authority_idx != AUTHORITY_DST_IDX) {
    nghttp2_nv authority = nva[authority_idx];
    for(i = authority_idx; i > AUTHORITY_DST_IDX; --i) {
      nva[i] = nva[i - 1];
    }
    nva[i] = authority;
  }

  switch(conn->data->set.httpreq) {
  case HTTPREQ_POST:
  case HTTPREQ_POST_FORM:
  case HTTPREQ_PUT:
    data_prd.read_callback = data_source_read_callback;
    data_prd.source.ptr = NULL;
    stream_id = nghttp2_submit_request(httpc->h2, NULL, nva, nheader,
                                       &data_prd, NULL);
    break;
  default:
    stream_id = nghttp2_submit_request(httpc->h2, NULL, nva, nheader,
                                       NULL, NULL);
  }

  Curl_safefree(nva);

  if(stream_id < 0) {
    *err = CURLE_SEND_ERROR;
    return -1;
  }

  httpc->stream_id = stream_id;

  rv = nghttp2_session_send(httpc->h2);

  if(rv != 0) {
    *err = CURLE_SEND_ERROR;
    return -1;
  }

  if(httpc->stream_id != -1) {
    /* If whole HEADERS frame was sent off to the underlying socket,
       the nghttp2 library calls data_source_read_callback. But only
       it found that no data available, so it deferred the DATA
       transmission. Which means that nghttp2_session_want_write()
       returns 0 on http2_perform_getsock(), which results that no
       writable socket check is performed. To workaround this, we
       issue nghttp2_session_resume_data() here to bring back DATA
       transmission from deferred state. */
    nghttp2_session_resume_data(httpc->h2, httpc->stream_id);
  }

  return len;
}

CURLcode Curl_http2_setup(struct connectdata *conn)
{
  struct http_conn *httpc = &conn->proto.httpc;
  if(conn->handler->flags & PROTOPT_SSL)
    conn->handler = &Curl_handler_http2_ssl;
  else
    conn->handler = &Curl_handler_http2;

  infof(conn->data, "Using HTTP2\n");
  httpc->bodystarted = FALSE;
  httpc->closed = FALSE;
  httpc->header_recvbuf = Curl_add_buffer_init();
  httpc->nread_header_recvbuf = 0;
  httpc->data = NULL;
  httpc->datalen = 0;
  httpc->upload_left = 0;
  httpc->upload_mem = NULL;
  httpc->upload_len = 0;
  httpc->stream_id = -1;
  httpc->status_code = -1;

  conn->httpversion = 20;

  return 0;
}

CURLcode Curl_http2_switched(struct connectdata *conn)
{
  CURLcode rc;
  struct http_conn *httpc = &conn->proto.httpc;
  int rv;
  struct SessionHandle *data = conn->data;

  httpc->recv_underlying = (recving)conn->recv[FIRSTSOCKET];
  httpc->send_underlying = (sending)conn->send[FIRSTSOCKET];
  conn->recv[FIRSTSOCKET] = http2_recv;
  conn->send[FIRSTSOCKET] = http2_send;

  rv = (int) ((Curl_send*)httpc->send_underlying)
    (conn, FIRSTSOCKET,
     NGHTTP2_CLIENT_CONNECTION_PREFACE,
     NGHTTP2_CLIENT_CONNECTION_PREFACE_LEN,
     &rc);
  if(rc)
    /* TODO: This may get CURLE_AGAIN */
    return rc;

  if(rv != 24) {
    failf(data, "Only sent partial HTTP2 packet");
    return CURLE_SEND_ERROR;
  }

  if(conn->data->req.upgr101 == UPGR101_RECEIVED) {
    /* stream 1 is opened implicitly on upgrade */
    httpc->stream_id = 1;
    /* queue SETTINGS frame (again) */
    rv = nghttp2_session_upgrade(httpc->h2, httpc->binsettings,
                                 httpc->binlen, NULL);
    if(rv != 0) {
      failf(data, "nghttp2_session_upgrade() failed: %s(%d)",
            nghttp2_strerror(rv), rv);
      return CURLE_HTTP2;
    }
  }
  else {
    /* stream ID is unknown at this point */
    httpc->stream_id = -1;
    rv = nghttp2_submit_settings(httpc->h2, NGHTTP2_FLAG_NONE, NULL, 0);
    if(rv != 0) {
      failf(data, "nghttp2_submit_settings() failed: %s(%d)",
            nghttp2_strerror(rv), rv);
      return CURLE_HTTP2;
    }
  }
  return CURLE_OK;
}

#endif