Commit graph

139 commits

Author SHA1 Message Date
Stefan Eissing
4d040c71d7
Curl_http(), decomplexify
Split out adding of individual request headers into a switch. Check
the connection http version only on fresh connections, use separate
methods.

Add TE: header directly without allocation. Add bit for indicating
Connection: header has been added and custom headers should not do
that again.

Closes #18444
2025-09-02 07:54:46 +02:00
Stefan Eissing
fa3baabbd8
websocket: improve handling of 0-len frames
Write out 9-length frames to client's WRITEFUNCTION
Read 0-length frames from READFUNCTION *if* the function
started a new frame via `curl_ws_start_frame()`.

Fixes #18286
Closes #18332
Reported-by: Andriy Druk
2025-08-28 11:00:02 +02:00
Stefan Eissing
37cecfc7b9
websocket: support CURLOPT_READFUNCTION
Add support for CURLOPT_READFUNCTION with WebSocket urls when *not* in
connect-only mode, e.g. when using curl_multi_perform.

Install the callback function and set CURLOPT_UPLOAD. Return
CURL_READFUNC_PAUSE when having nothing more to send and unpause the
transfer when more data is ready.

This will send the read bytes in a WebSocket BINARY frame.

Add support for this mode in the pytest "ws_data" client and have all
tests run in 'curl_ws_send/recv' and 'peform' mode as well.

Add `curl_ws_start_frame()`. Document, cover in libcurl-ws.md and
explain the READFUNCTION mode for websockets.

Add example `websocket-updown` for this.

Closes #17683
2025-08-11 23:28:54 +02:00
Stefan Eissing
5b80b4c012
lib: replace getsock() logic with pollsets
`getsock()` calls operated on a global limit that could
not be configure beyond 16 sockets. This is no longer adequate
with the new happy eyeballing strategy.

Instead, do the following:
- make `struct easy_pollset` dynamic. Starting with
  a minimal room for two sockets, the very common case,
  allow it to grow on demand.
- replace all protocol handler getsock() calls with pollsets
  and a CURLcode to return failures
- add CURLcode return for all connection filter `adjust_pollset()`
  callbacks, since they too can now fail.
- use appropriately in multi.c and multi_ev.c
- fix unit2600 to trigger pollset growth

Closes #18164
2025-08-04 23:43:13 +02:00
Daniel Stenberg
9d2075bdce
ws: avoid NULL pointer deref in curl_ws_recv
If a NULL easy handle is passed in.

Pointed out by Coverity

Follow-up to 960fb49245

Closes #18065
2025-07-28 22:37:59 +02:00
Viktor Szakats
4d977fe552
tidy-up: more whitespace/indent, comments
Also a couple of minor formatting updates in the root `CMakeLists.txt`.
One swap to `#ifdef`.

Closes #17929
2025-07-25 11:47:51 +02:00
Stefan Eissing
960fb49245
easy handle: check validity on external calls
In each external API function passing a `CURL *` into the library, check
`GOOD_EASY_HANDLE()` if its magic is still there.

Ref: #17957
Closes #17958
2025-07-20 23:11:05 +02:00
Patrick Stoeckle
86f43af951
misc: fix typos
Just fixing some typos using: https://github.com/crate-ci/typos

Closes #17904
2025-07-12 08:59:44 +02:00
Viktor Szakats
26f3ee25a4
ws: drop redundant CURL_EXTERN from function definitions
Cherry-picked from #17827
Closes #17832
2025-07-06 20:08:58 +02:00
Stefan Eissing
d4983ffc13
bufq: change read/write signatures
Change the signature of `bufq` functions from

* `ssize_t Curl_bufq_*(..., CURLcode *err)` to
* `CURLcode Curl_bufq_*(..., size_t *pn)`

This allows us to write slightly less code and avoids the ssize_t/size_t
conversions in many cases. Also, it gets the function in line with all
the other send/recv signatures.

Added helper functions in `cfilters.h` for sending from/receving into
a bufq.

Fuzzer now fails to build due to these changes and its testing of
the bufq API.

Closes #17396
2025-06-27 14:16:21 +02:00
Ruocco, Calvin
d3594be653
ws: tests and fixes
This started out as regression tests for the `curl_ws_recv()` and
`curl_ws_send()` implementation and ended up with a bugfix, additional
protocol validation and minor logging improvements.

- Fix reset of fragmented message decoder state when a PING/PONG is
  received in between message fragments.

- Fix undefined behavior (applying zero offset to null pointer) in
  curl_ws_send() when the given buffer is NULL.

- Detect invalid overlong PING/PONG/CLOSE frames.
- Detect invalid fragmented PING/PONG/CLOSE frames.
- Detect invalid sequences of fragmented frames.

  - a) A continuation frame (0x80...) is received without any ongoing
    fragmented message.
  - b) A new fragmented message is started (0x81/0x01/0x82/0x02...)
    before the ongoing fragmented message has terminated.

- Made logs for invalid opcodes easier to understand.
- Moved noisy logs to the `CURL_TRC_WS` log level.
- Unified the prefixes for WebSocket log messages: `[WS] ...`

- Add env var `CURL_WS_FORCE_ZERO_MASK` in debug builds.

  - If set, it forces the bit mask applied to outgoing payloads to
    0x00000000, which effectively means the payload is not masked at
    all. This drastically simplifies defining the expected `<protocol>`
    data in test cases.

- 2700: Frame types
- 2701: Invalid opcode 0x3
- 2702: Invalid opcode 0xB
- 2703: Invalid reserved bit RSV1 _(replaces 2310)_
- 2704: Invalid reserved bit RSV2
- 2705: Invalid reserved bit RSV3
- 2706: Invalid masked server message
- 2707: Peculiar frame sizes _(part. replaces 2311)_
- 2708: Automatic PONG
- 2709: No automatic PONG _(replaces 2312)_
- 2710: Unsolicited PONG
- 2711: Empty PING/PONG/CLOSE
- 2712: Max sized PING/PONG/CLOSE
- 2713: Invalid oversized PING _(replaces 2307)_
- 2714: Invalid oversized PONG
- 2715: Invalid oversized CLOSE
- 2716: Invalid fragmented PING
- 2717: Invalid fragmented PONG
- 2718: Invalid fragmented CLOSE
- 2719: Fragmented messages _(part. replaces 2311)_
- 2720: Fragmented messages with empty fragments
- 2721: Fragmented messages with interleaved pong
- 2722: Invalid fragmented message without initial frame
- 2723: Invalid fragmented message without final frame

- 2305: curl_ws_recv() loop reading three larger frames
  - This test involuntarily sent an invalid sequence of opcodes (0x01...,0x01...,0x81...) , but neither libcurl nor the test caught this! The correct sequence was tested in 2311 (0x01...,0x00...,0x80...). See below for 2311.
  - Validation of the opcode sequence was added to libcurl and is now tested in 2723.
  - Superseded by 2719 (fragmented message) and 2707 (large frames).
- 2307: overlong PING payload
  - The tested PING payload length check was actually missing, but the test didn't catch this since it involuntarily sent an invalid opcode (0x19... instead of 0x89...) so that the expected error occurred, but for the wrong reason.
  - Superseded by 2713.
- 2310: unknown reserved bit set in frame header
  - Superseded by 2703 and extended by 2704 and 2705.
- 2311: curl_ws_recv() read fragmented message
  - Superseded by 2719 (fragmented message) and 2707 (large frames).
- 2312: WebSockets no auto ping
  - Superseded by 2709.

- No tests for `CURLOPT_WRITEFUNCTION`.
- No tests for sending of invalid frames/fragments.

Closes #17136
2025-06-02 11:15:38 +02:00
z2_
d1145df24d
ws: handle blocked sends better
Closes #17496
2025-05-31 17:04:18 +02:00
Daniel Stenberg
4190c73094
curlx: move nonblock.[ch] into curlx/
Closes #17288
2025-05-08 13:22:02 +02:00
Daniel Stenberg
255aac56f9
curlx: move into to curlx/
Move curlx_ functions into its own subdir.

The idea is to use the curlx_ prefix proper on these functions, and use
these same function names both in tool, lib and test suite source code.
Stop the previous special #define setup for curlx_ names.

The printf defines are now done for the library alone. Tests no longer
use the printf defines. The tool code sets its own defines. The printf
functions are not curlx, they are publicly available.

The strcase defines are not curlx_ functions and should not be used by
tool or server code.

dynbuf, warnless, base64, strparse, timeval, timediff are now proper
curlx functions.

When libcurl is built statically, the functions from the library can be
used as-is. The key is then that the functions must work as-is, without
having to be recompiled for use in tool/tests. This avoids symbol
collisions - when libcurl is built statically, we use those functions
directly when building the tool/tests. When libcurl is shared, we
build/link them separately for the tool/tests.

Assisted-by: Jay Satiro

Closes #17253
2025-05-07 11:01:15 +02:00
Stefan Eissing
daa0601614
ws: store protocol context as connection meta data
Eliminates union member on struct connectdata. Sample of how
other procotols can handle their connection related data.

This avoids potention mix-ups of the `proto` union of a
connection with other protocol instances.

Removed ws "disconnect" callback as meta data is automatically
destroyed when a connection is destroyed.

Closes #17146
2025-04-28 09:15:05 +02:00
Daniel Stenberg
991c30d0d6
ws: fix the header replace check
It passed in the wrong header length to the check function, which made
it do duplicated headers in cases where the user provides its own set.

Reported-by: sbernatsky on github
Fixes #17170
Closes #17194
Closes #16178
2025-04-26 23:21:04 +02:00
Brian Chrzanowski
c0df01fd94
websocket: add option to disable auto-pong reply
This adds another bitflag on CURLOPT_WS_OPTIONS (CURLWS_NOAUTOPONG) that
disables the default and automatic PONG reply in the WebSocket layer.

Assisted-by: Calvin Ruocco

Closes #16744
2025-04-19 00:01:28 +02:00
Calvin Ruocco
3588df9478
ws: fix and extend CURLWS_CONT handling
Follow-up to fa3d1e7d43

Add test 2311 to verify

Closes #16687
2025-03-14 11:46:36 +01:00
Viktor Szakats
f4e23950c7
build: enable -Wcast-qual, fix or silence compiler warnings
The issues found fell into these categories, with the applied fixes:

- const was accidentally stripped.
  Adjust code to not cast or cast with const.

- const/volatile missing from arguments, local variables.
  Constify arguments or variables, adjust/delete casts. Small code
  changes in a few places.

- const must be stripped because an API dependency requires it.
  Strip `const` with `CURL_UNCONST()` macro to silence the warning out
  of our control. These happen at API boundaries. Sometimes they depend
  on dependency version, which this patch handles as necessary. Also
  enable const support for the zlib API, using `ZLIB_CONST`. Supported
  by zlib 1.2.5.2 and newer.

- const must be stripped because a curl API requires it.
  Strip `const` with `CURL_UNCONST()` macro to silence the warning out
  of our immediate control. For example we promise to send a non-const
  argument to a callback, though the data is const internally.

- other cases where we may avoid const stripping by code changes.
  Also silenced with `CURL_UNCONST()`.

- there are 3 places where `CURL_UNCONST()` is cast again to const.
  To silence this type of warning:
  ```
  lib/vquic/curl_osslq.c:1015:29: error: to be safe all intermediate
    pointers in cast from 'unsigned char **' to 'const unsigned char **'
    must be 'const' qualified [-Werror=cast-qual]
  lib/cf-socket.c:734:32: error: to be safe all intermediate pointers in
    cast from 'char **' to 'const char **' must be 'const' qualified
    [-Werror=cast-qual]
  ```
  There may be a better solution, but I couldn't find it.

These cases are handled in separate subcommits, but without further
markup.

If you see a `-Wcast-qual` warning in curl, we appreciate your report
about it.

Closes #16142
2025-03-10 22:30:15 +01:00
Ethan Wilkes
fa3d1e7d43
ws: corrected curlws_cont to reflect its documented purpose
Verified in test 2311

Closes #16512
2025-03-06 16:38:05 +01:00
Stefan Eissing
279a4772ae
http: negotiation and room for alt-svc/https rr to navigate
Add a 'wanted' major HTTP version bitmask next to the 'allowed' bitmask
in HTTP version negotiation. This will try connections as specified in
'wanted', but enabled Alt-Svc and HTTPS-RR to redirect to other major
HTTP versions, if those are 'allowed'.

Changes libcurl internal default to `CURL_HTTP_VERSION_NONE` and removes
the code in curl that sets `CURL_HTTP_VERSION_2TLS` if the command line
does not say anything else.

Closes #16117
2025-02-20 15:45:46 +01:00
Viktor Szakats
3fd1dfc829
tidy-up: use CURL_ARRAYSIZE()
Follow-up to 13b2ea68f0 #16111

Closes #16381
2025-02-19 00:59:45 +01:00
Stefan Eissing
db72b8d4d0
http: version negotiation
Translate the `data->set.httpwant` which is one of the consts from the
public API (CURL_HTTP_VERSION_*) into a major version mask plus
additional flags for internal handling.

`Curl_http_neg_init()` does the translation and flags setting in http.c,
using new internal consts CURL_HTTP_V1x, CURL_HTTP_V2x and CURL_HTTP_V3x
for the major versions. The flags are

- only_10: when the application explicity asked fro HTTP/1.0
- h2_upgrade: when the application asks for upgrading 1.1 to 2.
- h2_prior_knowledge: when directly talking h2 without ALPN
- accept_09: when a HTTP/0.9 response is acceptable.

The Alt-Svc and HTTPS RR redirections from one ALPN to another obey the
allowed major versions. If a transfer has only h3 enabled, Alt-Svc
redirection to h2 is ignored.

This is the current implementation. It can be debated if Alt-Svc should
be able to override the allowed major versions. Added test_12_06 to
verify the current restriction.

Closes #16100
2025-02-18 16:10:12 +01:00
Daniel Stenberg
b4538ec522
strparse: switch to curl_off_t as base data type
- add hex and octal parsers to the Curl_str_* family
- make curlx_strtoofft use these parsers
- remove all use of strtol() and strtoul() in library code
- generally use Curl_str_* more than strtoofft, for stricter parsing
- supports 64-bit universally, instead of 'long' which differs in size
  between platforms

Extended the unit test 1664 to verify hex and octal parsing.

Closes #16336
2025-02-15 21:58:48 +01:00
Andrew Kaster
1b740aedcd
ws: Reject frames with unknown reserved bits set
RFC 6455 Section 5.2 notes that for bits RSV1, RSV2, and RSV3 of the
framing header, a non-zero value that is not defined by a negotiated
extension MUST Fail the WebSocket connection.

Test 2310 verifies

Closes #16069
2025-01-28 10:19:39 +01:00
Stefan Eissing
1213c31272
lib: redirect handling by protocol handler
Adds a `follow()` callback to protocol handlers, so they may decide how
to act on a `newurl` after a request has been done. This is optional.

This moves the HTTP code for handling redirects from multi.c to http.c
where it should be. If we ever add a protocol with its own logic, it
would install its own follow function.

Closes #16075
2025-01-24 11:00:34 +01:00
Stefan Eissing
02edae54e8 websocket: fix message send corruption
- Fix a bug in EAGAIN handling when sending frames that led to a
  corrupted last byte of the frame sent.

- Restore sanity to curl_ws_send() behaviour:

  - Partial writes are reported as OK with the actual number of
    payload bytes sent.

  - CURLE_AGAIN is only returned when none of the payload bytes
    (or for 0-length frames, not all of the frame header bytes)
    could be sent.

  - curl_ws_send() now behaves like a common send() call.

- Change 'ws-data' test client to allow concurrent send/recv
  operations and vary frame sizes and repeat count.

- Add DEBUG env var CURL_WS_CHUNK_EAGAIN to simulate blocking
  after a chunk of an encoded websocket frame has been sent.

- Add tests.


Prior to this change data corruption may occur when sending websocket
messages due to two bugs:

1) 3e64569a (precedes 8.10.0) caused a data corruption bug in the last
   byte of frame of large messages.

2) curl_ws_send had non-traditional send behavior and could return
   CURLE_AGAIN with bytes sent and expect the caller to adjust buffer
   and buflen in a subsequent call. That behavior was not documented.


Reported-by: na-trium-144@users.noreply.github.com

Fixes https://github.com/curl/curl/issues/15865
Fixes https://github.com/curl/curl/issues/15865#issuecomment-2569870144
Closes https://github.com/curl/curl/pull/15901
2025-01-16 16:19:07 -05:00
Daniel Stenberg
fc3e1cbc50
hyper: drop support
lib : remove all hyper code
configure: stop detecting hyper
docs: no more mention of hyper
tests: mo more special-handling of hyper builds
CI: no jobs using hyper

Closes #15120
2024-12-21 11:33:05 +01:00
Daniel Stenberg
d6bae1cb8f
curl_ws_recv: return recv 0 and point meta to NULL on all errors
Previously it could accidentally return some errors without having reset
the values.

Closes #15342
2024-10-20 22:57:24 +02:00
Daniel Stenberg
eed3c8f4b7
curl.h: remove the struct pointer for CURL/CURLSH/CURLM typedefs
It makes the callbacks get different signnatures when used from within
libcurl vs outside of it by libcurl-using applications (such as the
libtests) and this triggers UndefinedBehaviorSanitizer errors.

Closes #15289
2024-10-15 14:33:40 +02:00
Daniel Stenberg
d78e129d50
WebSockets: make support official (non-experimental)
Inverts the configure/cmake options to instead provide options that
disable WebSockets and have them (ws + wss) enabled by default.

Closes #14936
2024-09-27 13:20:25 +02:00
Viktor Szakats
cfae354a9a
codespell: extend checks to more subdirs
- fix issues found.
- fix a few more found locally.

Closes #15072
2024-09-27 10:27:08 +02:00
Daniel Stenberg
fbf5d507ce
lib/src: white space edits to comply better with code style
... as checksrc now finds and complains about these.

Closes #14921
2024-09-19 14:59:12 +02:00
Daniel Stenberg
4ff04615a0
lib: use FMT_ as prefix instead of CURL_FORMAT_
For printf format defines used internally. Makes the code slighly
easier to read.

Closes #14764
2024-09-03 08:45:45 +02:00
Viktor Szakats
e512fbfa67
printf: fix mingw-w64 format checks
Change mingw-w64 printf format checks in public curl headers to use
`__MINGW_PRINTF_FORMAT` instead of `gnu_printf`. This syncs the format
checker with format string macros published via `curl/system.h`. (Also
disable format checks for mingw-w64 older than 3.0.0 (2013-09-20) and
classic-mingw, which do not support this macro.)

This fixes bogus format checker `-Wformat` warnings in 3rd party code
using curl format strings with the curl printf functions, when using
mingw-w64 7.0.0 (2019-11-10) and older (with GCC, MSVCRT).

It also allows to delete two workaounds for this within curl itself:
- setting `-D__USE_MINGW_ANSI_STDIO=1` for mingw-w64 via cmake and
  configure for `docs/examples` and `tests/http/clients`.
  Ref: c730c8549b #14640

The format check macro is incompatible (depending on mingw-w64 version
and configuration) with the C99 `%z` (`size_t`) format string used
internally by curl.

To work around this problem, override the format check style in curl
public headers to use `gnu_printf`. This is compatible with `%z` in all
mingw-w64 versions and allows keeping the C99 format strings internally.

Also:
- lib/ws.c: add missing space to an error message.
- docs/examples/ftpgetinfo.c: fix to use standard printf.

Ref: #14643 (take 1)
Follow-up to 3829759bd0 #12489

Closes #14703
2024-09-02 21:03:01 +02:00
Viktor Szakats
42843af0b8
tidy-up: spelling WebSockets
Closes #14646
2024-08-22 17:43:57 +02:00
Stefan Eissing
3e64569a9e
websocket: introduce blocking sends
When using `curl_ws_send()`, perform a blocking send of the data under
the following conditions:

- the websocket is in raw mode and the call is done from within a curl
  callback. A partial write of the data could subsequently mess up the
  ws framing, as a callback has a hard time handling this.

- the websocket is encoding the data itself, has added it to its
  internal sendbuf. A partial flush of the buffer has unclear semantics
  for the caller, as they will have no idea what to send again.

Fixes WebSockets tests with CURL_DBG_SOCK_WBLOCK=90 set.
Closes #14458
2024-08-12 19:19:28 +02:00
Pete Cordell
0011df47bc
ws: flags to opcodes should ignore CURLWS_CONT flag
When converting WebSocket flags such as CURLWS_TEXT | CURLWS_CONT we
want to exclude CURLWS_CONT from the lookup.

Closes #14397
2024-08-07 09:06:30 +02:00
Stefan Eissing
911c3166b6
lib: add eos flag to send methods
Adds a `bool eos` flag to send methods to indicate that the data
is the last chunk the invovled transfer wants to send to the server.

This will help protocol filters like HTTP/2 and 3 to forward the
stream's EOF flag and also allow to EAGAIN such calls when buffers
are not yet fully flushed.

Closes #14220
2024-08-03 19:53:54 +02:00
Daniel Stenberg
25321de30e
Revert "lib: send eos flag"
This reverts commit be93299f10.
2024-07-19 01:38:05 +02:00
Stefan Eissing
be93299f10
lib: send eos flag
Adds a `bool eos` flag to send methods to indicate that the data is the
last chunk the invovled transfer wants to send to the server.

This will help protocol filters like HTTP/2 and 3 to forward the
stream's EOF flag and also allow to EAGAIN such calls when buffers are
not yet fully flushed.

Closes #14220
2024-07-18 23:27:35 +02:00
Daniel Stenberg
c074ba64a8
code: language cleanup in comments
Based on the standards and guidelines we use for our documentation.

 - expand contractions (they're => they are etc)
 - host name = > hostname
 - file name => filename
 - user name = username
 - man page => manpage
 - run-time => runtime
 - set-up => setup
 - back-end => backend
 - a HTTP => an HTTP
 - Two spaces after a period => one space after period

Closes #14073
2024-07-01 22:58:55 +02:00
Viktor Szakats
72abf7c13a
lib: tidy up types and casts
Cherry-picked from #13489
Closes #13862
2024-06-05 14:02:39 +02:00
Daniel Gustafsson
266baf2d34 websocket: Avoid memory leak in error path
In the errorpath for randstr being too long to copy into the buffer
we leak the randstr when returning CURLE_FAILED_INIT.  Fix by using
an explicit free on randstr in the errorpath.

Closes: #13602
Reviewed-by: Daniel Stenberg <daniel@haxx.se>
2024-05-13 09:11:23 +02:00
Daniel Stenberg
25236c6a80
multi: remove the unused Curl_preconnect function
The implementation has been removed, no point in keeping it around.

Follow-up to 476adfeac0

Closes #13422
2024-04-19 15:06:48 +02:00
Stefan Eissing
8dd81bd5db
lib: add Curl_xfer_write_resp_hd
Add method in protocol handlers to allow writing of a single,
0-terminated header line. Avoids parsing and copying these lines.

Closes #13165
2024-04-11 09:29:21 +02:00
Stefan Eissing
0b28ece657
lib: add trace support for client reads and writes
- add `CURL_TRC_READ()` and `CURL_TRC_WRITE()`
- use in generic client writers and readers, as well
  as http headers, chunking and websockets

Closes #13223
2024-04-05 16:08:10 +02:00
Stefan Eissing
a586b8ca40
lib: client reader polish
- seek_func/seek_client, use transfer values only
    - remove copies held in `struct connectdata`, use only
      ever `data->set.seek_func`
    - resolves possible issues in multiuse connections
    - new mime post reader eliminates need to ever overwriting this

- websockets, remove empty Curl_ws_done() function

Closes #13079
2024-03-08 13:11:17 +01:00
Stefan Eissing
9978d40ddb
lib: add void *ctx to reader/writer instances
- `struct Curl_cwriter` and `struct Curl_creader` now carry a
  `void *ctx` member that points to the instance as allocated.
- using `r->ctx` and `w->ctx` as pointer to the instance specific
  struct that has been allocated

Reported-by: Rudi Heitbaum
Fixes #13035
Closes #13059
2024-03-06 14:38:12 +01:00
Stefan Eissing
3755153571
lib: Curl_read/Curl_write clarifications
- replace `Curl_read()`, `Curl_write()` and `Curl_nwrite()` to
  clarify when and at what level they operate
- send/recv of transfer related data is now done via
  `Curl_xfer_send()/Curl_xfer_recv()` which no longer has
  socket/socketindex as parameter. It decides on the transfer
  setup of `conn->sockfd` and `conn->writesockfd` on which
  connection filter chain to operate.
- send/recv on a specific connection filter chain is done via
  `Curl_conn_send()/Curl_conn_recv()` which get the socket index
  as parameter.
- rename `Curl_setup_transfer()` to `Curl_xfer_setup()` for
  naming consistency
- clarify that the special CURLE_AGAIN hangling to return
  `CURLE_OK` with length 0 only applies to `Curl_xfer_send()`
  and CURLE_AGAIN is returned by all other send() variants.
- fix a bug in websocket `curl_ws_recv()` that mixed up data
  when it arrived in more than a single chunk

The method for sending not just raw bytes, but bytes that are either
"headers" or "body". The send abstraction stack, to to bottom, now is:

* `Curl_req_send()`: has parameter to indicate amount of header bytes,
  buffers all data.
* `Curl_xfer_send()`: knows on which socket index to send, returns
  amount of bytes sent.
* `Curl_conn_send()`: called with socket index, returns amount of bytes
  sent.

In addition there is `Curl_req_flush()` for writing out all buffered
bytes.

`Curl_req_send()` is active for requests without body,
`Curl_buffer_send()` still being used for others. This is because the
special quirks need to be addressed in future parts:

* `expect-100` handling
* `Curl_fillreadbuffer()` needs to add directly to the new
  `data->req.sendbuf`
* special body handlings, like `chunked` encodings and line end
  conversions will be moved into something like a Client Reader.

In functions of the pattern `CURLcode xxx_send(..., ssize_t *written)`,
replace the `ssize_t` with a `size_t`. It makes no sense to allow for negative
values as the returned `CURLcode` already specifies error conditions. This
allows easier handling of lengths without casting.

Closes #12964
2024-02-27 14:13:56 +01:00