quickjs-tart

TODO (49834B)

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                 Things that could be nice to do in the future
 
  Things to do in project curl. Please tell us what you think, contribute and
  send us patches that improve things.
 
  Be aware that these are things that we could do, or have once been considered
  things we could do. If you want to work on any of these areas, please
  consider bringing it up for discussions first on the mailing list so that we
  all agree it is still a good idea for the project.
 
  All bugs documented in the KNOWN_BUGS document are subject for fixing.
 
  1. libcurl
  1.1 TFO support on Windows
  1.2 Consult %APPDATA% also for .netrc
  1.3 struct lifreq
  1.4 alt-svc sharing
  1.5 get rid of PATH_MAX
  1.6 thread-safe sharing
  1.8 CURLOPT_RESOLVE for any port number
  1.9 Cache negative name resolves
  1.10 auto-detect proxy
  1.11 minimize dependencies with dynamically loaded modules
  1.12 updated DNS server while running
  1.13 c-ares and CURLOPT_OPENSOCKETFUNCTION
  1.14 connect to multiple IPs in parallel
  1.15 Monitor connections in the connection pool
  1.16 Try to URL encode given URL
  1.17 Add support for IRIs
  1.18 try next proxy if one does not work
  1.19 provide timing info for each redirect
  1.20 SRV and URI DNS records
  1.21 netrc caching and sharing
  1.22 CURLINFO_PAUSE_STATE
  1.23 Offer API to flush the connection pool
  1.25 Expose tried IP addresses that failed
  1.28 FD_CLOEXEC
  1.29 WebSocket read callback
  1.30 config file parsing
  1.31 erase secrets from heap/stack after use
  1.32 add asynch getaddrinfo support
  1.33 make DoH inherit more transfer properties
 
  2. libcurl - multi interface
  2.1 More non-blocking
  2.2 Better support for same name resolves
  2.3 Non-blocking curl_multi_remove_handle()
  2.4 Split connect and authentication process
  2.5 Edge-triggered sockets should work
  2.6 multi upkeep
  2.7 Virtual external sockets
  2.8 dynamically decide to use socketpair
 
  3. Documentation
  3.1 Improve documentation about fork safety
 
  4. FTP
  4.1 HOST
  4.6 GSSAPI via Windows SSPI
  4.7 STAT for LIST without data connection
  4.8 Passive transfer could try other IP addresses
 
  5. HTTP
  5.1 Provide the error body from a CONNECT response
  5.2 Obey Retry-After in redirects
  5.3 Rearrange request header order
  5.4 Allow SAN names in HTTP/2 server push
  5.5 auth= in URLs
  5.6 alt-svc should fallback if alt-svc does not work
  5.7 Require HTTP version X or higher
 
  6. TELNET
  6.1 ditch stdin
  6.2 ditch telnet-specific select
  6.3 feature negotiation debug data
  6.4 exit immediately upon connection if stdin is /dev/null
 
  7. SMTP
  7.1 Passing NOTIFY option to CURLOPT_MAIL_RCPT
  7.2 Enhanced capability support
  7.3 Add CURLOPT_MAIL_CLIENT option
 
  8. POP3
  8.2 Enhanced capability support
 
  9. IMAP
  9.1 Enhanced capability support
 
  10. LDAP
  10.1 SASL based authentication mechanisms
  10.2 CURLOPT_SSL_CTX_FUNCTION for LDAPS
  10.3 Paged searches on LDAP server
  10.4 Certificate-Based Authentication
 
  11. SMB
  11.1 File listing support
  11.2 Honor file timestamps
  11.3 Use NTLMv2
  11.4 Create remote directories
 
  12. FILE
  12.1 Directory listing on non-POSIX
 
  13. TLS
  13.1 TLS-PSK with OpenSSL
  13.2 TLS channel binding
  13.3 Defeat TLS fingerprinting
  13.4 Consider OCSP stapling by default
  13.5 Export session ids
  13.6 Provide callback for cert verification
  13.7 Less memory massaging with Schannel
  13.8 Support DANE
  13.9 TLS record padding
  13.10 Support Authority Information Access certificate extension (AIA)
  13.11 Some TLS options are not offered for HTTPS proxies
  13.13 Make sure we forbid TLS 1.3 post-handshake authentication
  13.14 Support the clienthello extension
  13.16 Share the CA cache
  13.17 Add missing features to TLS backends
 
  14. Proxy
  14.1 Retry SOCKS handshake on address type not supported
 
  15. Schannel
  15.1 Extend support for client certificate authentication
  15.2 Extend support for the --ciphers option
  15.4 Add option to allow abrupt server closure
 
  16. SASL
  16.1 Other authentication mechanisms
  16.2 Add QOP support to GSSAPI authentication
 
  17. SSH protocols
  17.1 Multiplexing
  17.2 Handle growing SFTP files
  17.3 Read keys from ~/.ssh/id_ecdsa, id_ed25519
  17.4 Support CURLOPT_PREQUOTE
  17.5 SSH over HTTPS proxy with more backends
  17.6 SFTP with SCP://
 
  18. Command line tool
  18.1 sync
  18.2 glob posts
  18.4 --proxycommand
  18.5 UTF-8 filenames in Content-Disposition
  18.6 Option to make -Z merge lined based outputs on stdout
  18.7 specify which response codes that make -f/--fail return error
  18.9 Choose the name of file in braces for complex URLs
  18.10 improve how curl works in a Windows console window
  18.11 Windows: set attribute 'archive' for completed downloads
  18.12 keep running, read instructions from pipe/socket
  18.13 Acknowledge Ratelimit headers
  18.14 --dry-run
  18.15 --retry should resume
  18.17 consider filename from the redirected URL with -O ?
  18.18 retry on network is unreachable
  18.19 expand ~/ in config files
  18.20 hostname sections in config files
  18.21 retry on the redirected-to URL
  18.23 Set the modification date on an uploaded file
  18.24 Use multiple parallel transfers for a single download
  18.25 Prevent terminal injection when writing to terminal
  18.26 Custom progress meter update interval
  18.27 -J and -O with %-encoded filenames
  18.28 -J with -C -
  18.29 --retry and transfer timeouts
 
  19. Build
  19.2 Enable PIE and RELRO by default
  19.3 Do not use GNU libtool on OpenBSD
  19.4 Package curl for Windows in a signed installer
  19.5 make configure use --cache-file more and better
 
  20. Test suite
  20.1 SSL tunnel
  20.2 more protocols supported
  20.3 more platforms supported
  20.4 write an SMB test server to replace impacket
  20.5 Use the RFC 6265 test suite
  20.6 Run web-platform-tests URL tests
 
  21. MQTT
  21.1 Support rate-limiting
  21.2 Support MQTTS
  21.3 Handle network blocks
 
  22. TFTP
  22.1 TFTP does not convert LF to CRLF for mode=netascii
 
  23. Gopher
  23.1 Handle network blocks
 
 ==============================================================================
 
 1. libcurl
 
 1.1 TFO support on Windows
 
  libcurl supports the CURLOPT_TCP_FASTOPEN option since 7.49.0 for Linux and
  macOS. Windows supports TCP Fast Open starting with Windows 10, version 1607
  and we should add support for it.
 
  TCP Fast Open is supported on several platforms but not on Windows. Work on
  this was once started but never finished.
 
  See https://github.com/curl/curl/pull/3378
 
 1.2 Consult %APPDATA% also for .netrc
 
  %APPDATA%\.netrc is not considered when running on Windows. should not it?
 
  See https://github.com/curl/curl/issues/4016
 
 1.3 struct lifreq
 
  Use 'struct lifreq' and SIOCGLIFADDR instead of 'struct ifreq' and
  SIOCGIFADDR on newer Solaris versions as they claim the latter is obsolete.
  To support IPv6 interface addresses for network interfaces properly.
 
 1.4 alt-svc sharing
 
  The share interface could benefit from allowing the alt-svc cache to be
  possible to share between easy handles.
 
  See https://github.com/curl/curl/issues/4476
 
  The share interface offers CURL_LOCK_DATA_CONNECT to have multiple easy
  handle share a connection cache, but due to how connections are used they are
  still not thread-safe when used shared.
 
  See https://github.com/curl/curl/issues/4915 and lib1541.c
 
  The share interface offers CURL_LOCK_DATA_HSTS to have multiple easy handle
  share an HSTS cache, but this is not thread-safe.
 
 1.5 get rid of PATH_MAX
 
  Having code use and rely on PATH_MAX is not nice:
  https://insanecoding.blogspot.com/2007/11/pathmax-simply-isnt.html
 
  Currently the libssh2 SSH based code uses it, but to remove PATH_MAX from
  there we need libssh2 to properly tell us when we pass in a too small buffer
  and its current API (as of libssh2 1.2.7) does not.
 
 1.6 thread-safe sharing
 
  Using the share interface users can share some data between easy handles but
  several of the sharing options are documented as not safe and supported to
  share between multiple concurrent threads. Fixing this would enable more
  users to share data in more powerful ways.
 
 1.8 CURLOPT_RESOLVE for any port number
 
  This option allows applications to set a replacement IP address for a given
  host + port pair. Consider making support for providing a replacement address
  for the hostname on all port numbers.
 
  See https://github.com/curl/curl/issues/1264
 
 1.9 Cache negative name resolves
 
  A name resolve that has failed is likely to fail when made again within a
  short period of time. Currently we only cache positive responses.
 
 1.10 auto-detect proxy
 
  libcurl could be made to detect the system proxy setup automatically and use
  that. On Windows, macOS and Linux desktops for example.
 
  The pull-request to use libproxy for this was deferred due to doubts on the
  reliability of the dependency and how to use it:
  https://github.com/curl/curl/pull/977
 
  libdetectproxy is a (C++) library for detecting the proxy on Windows
  https://github.com/paulharris/libdetectproxy
 
 1.11 minimize dependencies with dynamically loaded modules
 
  We can create a system with loadable modules/plug-ins, where these modules
  would be the ones that link to 3rd party libs. That would allow us to avoid
  having to load ALL dependencies since only the necessary ones for this
  app/invoke/used protocols would be necessary to load. See
  https://github.com/curl/curl/issues/349
 
 1.12 updated DNS server while running
 
  If /etc/resolv.conf gets updated while a program using libcurl is running, it
  is may cause name resolves to fail unless res_init() is called. We should
  consider calling res_init() + retry once unconditionally on all name resolve
  failures to mitigate against this. Firefox works like that. Note that Windows
  does not have res_init() or an alternative.
 
  https://github.com/curl/curl/issues/2251
 
 1.13 c-ares and CURLOPT_OPENSOCKETFUNCTION
 
  curl creates most sockets via the CURLOPT_OPENSOCKETFUNCTION callback and
  close them with the CURLOPT_CLOSESOCKETFUNCTION callback. However, c-ares
  does not use those functions and instead opens and closes the sockets itself.
  This means that when curl passes the c-ares socket to the
  CURLMOPT_SOCKETFUNCTION it is not owned by the application like other
  sockets.
 
  See https://github.com/curl/curl/issues/2734
 
 1.14 connect to multiple IPs in parallel
 
  curl currently implements the happy eyeball algorithm for connecting to the
  IPv4 and IPv6 alternatives for a host in parallel, sticking with the
  connection that "wins". We could implement a similar algorithm per individual
  IP family as well when there are multiple available addresses: start with the
  first address, then start a second attempt N milliseconds after and then a
  third another N milliseconds later. That way there would be less waiting when
  the first IP has problems. It also improves the connection timeout value
  handling for multiple address situations.
 
 1.15 Monitor connections in the connection pool
 
  libcurl's connection cache or pool holds a number of open connections for the
  purpose of possible subsequent connection reuse. It may contain a few up to a
  significant amount of connections. Currently, libcurl leaves all connections
  as they are and first when a connection is iterated over for matching or
  reuse purpose it is verified that it is still alive.
 
  Those connections may get closed by the server side for idleness or they may
  get an HTTP/2 ping from the peer to verify that they are still alive. By
  adding monitoring of the connections while in the pool, libcurl can detect
  dead connections (and close them) better and earlier, and it can handle
  HTTP/2 pings to keep such ones alive even when not actively doing transfers
  on them.
 
 1.16 Try to URL encode given URL
 
  Given a URL that for example contains spaces, libcurl could have an option
  that would try somewhat harder than it does now and convert spaces to %20 and
  perhaps URL encoded byte values over 128 etc (basically do what the redirect
  following code already does).
 
  https://github.com/curl/curl/issues/514
 
 1.17 Add support for IRIs
 
  IRIs (RFC 3987) allow localized, non-ASCII, names in the URL. To properly
  support this, curl/libcurl would need to translate/encode the given input
  from the input string encoding into percent encoded output "over the wire".
 
  To make that work smoothly for curl users even on Windows, curl would
  probably need to be able to convert from several input encodings.
 
 1.18 try next proxy if one does not work
 
  Allow an application to specify a list of proxies to try, and failing to
  connect to the first go on and try the next instead until the list is
  exhausted. Browsers support this feature at least when they specify proxies
  using PACs.
 
  https://github.com/curl/curl/issues/896
 
 1.19 provide timing info for each redirect
 
  curl and libcurl provide timing information via a set of different
  time-stamps (CURLINFO_*_TIME). When curl is following redirects, those
  returned time value are the accumulated sums. An improvement could be to
  offer separate timings for each redirect.
 
  https://github.com/curl/curl/issues/6743
 
 1.20 SRV and URI DNS records
 
  Offer support for resolving SRV and URI DNS records for libcurl to know which
  server to connect to for various protocols (including HTTP).
 
 1.21 netrc caching and sharing
 
  The netrc file is read and parsed each time a connection is setup, which
  means that if a transfer needs multiple connections for authentication or
  redirects, the file might be reread (and parsed) multiple times. This makes
  it impossible to provide the file as a pipe.
 
 1.22 CURLINFO_PAUSE_STATE
 
  Return information about the transfer's current pause state, in both
  directions. https://github.com/curl/curl/issues/2588
 
 1.23 Offer API to flush the connection pool
 
  Sometimes applications want to flush all the existing connections kept alive.
  An API could allow a forced flush or just a forced loop that would properly
  close all connections that have been closed by the server already.
 
 1.25 Expose tried IP addresses that failed
 
  When libcurl fails to connect to a host, it could offer the application the
  addresses that were used in the attempt. Source + dest IP, source + dest port
  and protocol (UDP or TCP) for each failure. Possibly as a callback. Perhaps
  also provide "reason".
 
  https://github.com/curl/curl/issues/2126
 
 1.28 FD_CLOEXEC
 
  It sets the close-on-exec flag for the file descriptor, which causes the file
  descriptor to be automatically (and atomically) closed when any of the
  exec-family functions succeed. Should probably be set by default?
 
  https://github.com/curl/curl/issues/2252
 
 1.29 WebSocket read callback
 
  Call the read callback once the connection is established to allow sending
  the first message in the connection.
 
  https://github.com/curl/curl/issues/11402
 
 1.30 config file parsing
 
  Consider providing an API, possibly in a separate companion library, for
  parsing a config file like curl's -K/--config option to allow applications to
  get the same ability to read curl options from files.
 
  See https://github.com/curl/curl/issues/3698
 
 1.31 erase secrets from heap/stack after use
 
  Introducing a concept and system to erase secrets from memory after use, it
  could help mitigate and lessen the impact of (future) security problems etc.
  However: most secrets are passed to libcurl as clear text from the
  application and then clearing them within the library adds nothing...
 
  https://github.com/curl/curl/issues/7268
 
 1.32 add asynch getaddrinfo support
 
  Use getaddrinfo_a() to provide an asynch name resolver backend to libcurl
  that does not use threads and does not depend on c-ares. The getaddrinfo_a
  function is (probably?) glibc specific but that is a widely used libc among
  our users.
 
  https://github.com/curl/curl/pull/6746
 
 1.33 make DoH inherit more transfer properties
 
  Some options are not inherited because they are not relevant for the DoH SSL
  connections, or inheriting the option may result in unexpected behavior. For
  example the user's debug function callback is not inherited because it would
  be unexpected for internal handles (ie DoH handles) to be passed to that
  callback.
 
  If an option is not inherited then it is not possible to set it separately
  for DoH without a DoH-specific option. For example:
  CURLOPT_DOH_SSL_VERIFYHOST, CURLOPT_DOH_SSL_VERIFYPEER and
  CURLOPT_DOH_SSL_VERIFYSTATUS.
 
  See https://github.com/curl/curl/issues/6605
 
 2. libcurl - multi interface
 
 2.1 More non-blocking
 
  Make sure we do not ever loop because of non-blocking sockets returning
  EWOULDBLOCK or similar. Blocking cases include:
 
  - Name resolves on non-Windows unless c-ares or the threaded resolver is used.
 
  - The threaded resolver may block on cleanup:
  https://github.com/curl/curl/issues/4852
 
  - file:// transfers
 
  - TELNET transfers
 
  - GSSAPI authentication for FTP transfers
 
  - The "DONE" operation (post transfer protocol-specific actions) for the
  protocols SFTP, SMTP, FTP. Fixing multi_done() for this is a worthy task.
 
  - curl_multi_remove_handle for any of the above. See section 2.3.
 
  - Calling curl_ws_send() from a callback
 
 2.2 Better support for same name resolves
 
  If a name resolve has been initiated for name NN and a second easy handle
  wants to resolve that name as well, make it wait for the first resolve to end
  up in the cache instead of doing a second separate resolve. This is
  especially needed when adding many simultaneous handles using the same host
  name when the DNS resolver can get flooded.
 
 2.3 Non-blocking curl_multi_remove_handle()
 
  The multi interface has a few API calls that assume a blocking behavior, like
  add_handle() and remove_handle() which limits what we can do internally. The
  multi API need to be moved even more into a single function that "drives"
  everything in a non-blocking manner and signals when something is done. A
  remove or add would then only ask for the action to get started and then
  multi_perform() etc still be called until the add/remove is completed.
 
 2.4 Split connect and authentication process
 
  The multi interface treats the authentication process as part of the connect
  phase. As such any failures during authentication does not trigger the
  relevant QUIT or LOGOFF for protocols such as IMAP, POP3 and SMTP.
 
 2.5 Edge-triggered sockets should work
 
  The multi_socket API should work with edge-triggered socket events. One of
  the internal actions that need to be improved for this to work perfectly is
  the 'maxloops' handling in transfer.c:readwrite_data().
 
 2.6 multi upkeep
 
  In libcurl 7.62.0 we introduced curl_easy_upkeep. It unfortunately only works
  on easy handles. We should introduces a version of that for the multi handle,
  and also consider doing "upkeep" automatically on connections in the
  connection pool when the multi handle is in used.
 
  See https://github.com/curl/curl/issues/3199
 
 2.7 Virtual external sockets
 
  libcurl performs operations on the given file descriptor that presumes it is
  a socket and an application cannot replace them at the moment. Allowing an
  application to fully replace those would allow a larger degree of freedom and
  flexibility.
 
  See https://github.com/curl/curl/issues/5835
 
 2.8 dynamically decide to use socketpair
 
  For users who do not use curl_multi_wait() or do not care for
  curl_multi_wakeup(), we could introduce a way to make libcurl NOT
  create a socketpair in the multi handle.
 
  See https://github.com/curl/curl/issues/4829
 
 3. Documentation
 
 3.1 Improve documentation about fork safety
 
  See https://github.com/curl/curl/issues/6968
 
 4. FTP
 
 4.1 HOST
 
  HOST is a command for a client to tell which hostname to use, to offer FTP
  servers named-based virtual hosting:
 
  https://datatracker.ietf.org/doc/html/rfc7151
 
 4.6 GSSAPI via Windows SSPI
 
  In addition to currently supporting the SASL GSSAPI mechanism (Kerberos V5)
  via third-party GSS-API libraries, such as Heimdal or MIT Kerberos, also add
  support for GSSAPI authentication via Windows SSPI.
 
 4.7 STAT for LIST without data connection
 
  Some FTP servers allow STAT for listing directories instead of using LIST,
  and the response is then sent over the control connection instead of as the
  otherwise usedw data connection: https://www.nsftools.com/tips/RawFTP.htm#STAT
 
  This is not detailed in any FTP specification.
 
 4.8 Passive transfer could try other IP addresses
 
  When doing FTP operations through a proxy at localhost, the reported spotted
  that curl only tried to connect once to the proxy, while it had multiple
  addresses and a failed connect on one address should make it try the next.
 
  After switching to passive mode (EPSV), curl could try all IP addresses for
  "localhost". Currently it tries ::1, but it should also try 127.0.0.1.
 
  See https://github.com/curl/curl/issues/1508
 
 5. HTTP
 
 5.1 Provide the error body from a CONNECT response
 
  When curl receives a body response from a CONNECT request to a proxy, it
  always just reads and ignores it. It would make some users happy if curl
  instead optionally would be able to make that responsible available. Via a
  new callback? Through some other means?
 
  See https://github.com/curl/curl/issues/9513
 
 5.2 Obey Retry-After in redirects
 
  The Retry-After is said to dicate "the minimum time that the user agent is
  asked to wait before issuing the redirected request" and libcurl does not
  obey this.
 
  See https://github.com/curl/curl/issues/11447
 
 5.3 Rearrange request header order
 
  Server implementers often make an effort to detect browser and to reject
  clients it can detect to not match. One of the last details we cannot yet
  control in libcurl's HTTP requests, which also can be exploited to detect
  that libcurl is in fact used even when it tries to impersonate a browser, is
  the order of the request headers. I propose that we introduce a new option in
  which you give headers a value, and then when the HTTP request is built it
  sorts the headers based on that number. We could then have internally created
  headers use a default value so only headers that need to be moved have to be
  specified.
 
 5.4 Allow SAN names in HTTP/2 server push
 
  curl only allows HTTP/2 push promise if the provided :authority header value
  exactly matches the hostname given in the URL. It could be extended to allow
  any name that would match the Subject Alternative Names in the server's TLS
  certificate.
 
  See https://github.com/curl/curl/pull/3581
 
 5.5 auth= in URLs
 
  Add the ability to specify the preferred authentication mechanism to use by
  using ;auth=<mech> in the login part of the URL.
 
  For example:
 
  http://test:pass;auth=NTLM@example.com would be equivalent to specifying
  --user test:pass;auth=NTLM or --user test:pass --ntlm from the command line.
 
  Additionally this should be implemented for proxy base URLs as well.
 
 5.6 alt-svc should fallback if alt-svc does not work
 
  The alt-svc: header provides a set of alternative services for curl to use
  instead of the original. If the first attempted one fails, it should try the
  next etc and if all alternatives fail go back to the original.
 
  See https://github.com/curl/curl/issues/4908
 
 5.7 Require HTTP version X or higher
 
  curl and libcurl provide options for trying higher HTTP versions (for example
  HTTP/2) but then still allows the server to pick version 1.1. We could
  consider adding a way to require a minimum version.
 
  See https://github.com/curl/curl/issues/7980
 
 6. TELNET
 
 6.1 ditch stdin
 
  Reading input (to send to the remote server) on stdin is a crappy solution
  for library purposes. We need to invent a good way for the application to be
  able to provide the data to send.
 
 6.2 ditch telnet-specific select
 
  Move the telnet support's network select() loop go away and merge the code
  into the main transfer loop. Until this is done, the multi interface does not
  work for telnet.
 
 6.3 feature negotiation debug data
 
  Add telnet feature negotiation data to the debug callback as header data.
 
 6.4 exit immediately upon connection if stdin is /dev/null
 
  If it did, curl could be used to probe if there is an server there listening
  on a specific port. That is, the following command would exit immediately
  after the connection is established with exit code 0:
 
     curl -s --connect-timeout 2 telnet://example.com:80 </dev/null
 
 7. SMTP
 
 7.1 Passing NOTIFY option to CURLOPT_MAIL_RCPT
 
  Is there a way to pass the NOTIFY option to the CURLOPT_MAIL_RCPT option ?  I
  set a string that already contains a bracket. For instance something like
  that: curl_slist_append( recipients, "<foo@bar> NOTIFY=SUCCESS,FAILURE" );
 
  https://github.com/curl/curl/issues/8232
 
 7.2 Enhanced capability support
 
  Add the ability, for an application that uses libcurl, to obtain the list of
  capabilities returned from the EHLO command.
 
 7.3 Add CURLOPT_MAIL_CLIENT option
 
  Rather than use the URL to specify the mail client string to present in the
  HELO and EHLO commands, libcurl should support a new CURLOPT specifically for
  specifying this data as the URL is non-standard and to be honest a bit of a
  hack ;-)
 
  Please see the following thread for more information:
  https://curl.se/mail/lib-2012-05/0178.html
 
 
 8. POP3
 
 8.2 Enhanced capability support
 
  Add the ability, for an application that uses libcurl, to obtain the list of
  capabilities returned from the CAPA command.
 
 9. IMAP
 
 9.1 Enhanced capability support
 
  Add the ability, for an application that uses libcurl, to obtain the list of
  capabilities returned from the CAPABILITY command.
 
 10. LDAP
 
 10.1 SASL based authentication mechanisms
 
  Currently the LDAP module only supports ldap_simple_bind_s() in order to bind
  to an LDAP server. However, this function sends username and password details
  using the simple authentication mechanism (as clear text). However, it should
  be possible to use ldap_bind_s() instead specifying the security context
  information ourselves.
 
 10.2 CURLOPT_SSL_CTX_FUNCTION for LDAPS
 
  CURLOPT_SSL_CTX_FUNCTION works perfectly for HTTPS and email protocols, but
  it has no effect for LDAPS connections.
 
  https://github.com/curl/curl/issues/4108
 
 10.3 Paged searches on LDAP server
 
  https://github.com/curl/curl/issues/4452
 
 10.4 Certificate-Based Authentication
 
  LDAPS not possible with macOS and Windows with Certificate-Based Authentication
 
  https://github.com/curl/curl/issues/9641
 
 11. SMB
 
 11.1 File listing support
 
  Add support for listing the contents of an SMB share. The output should
  probably be the same as/similar to FTP.
 
 11.2 Honor file timestamps
 
  The timestamp of the transferred file should reflect that of the original
  file.
 
 11.3 Use NTLMv2
 
  Currently the SMB authentication uses NTLMv1.
 
 11.4 Create remote directories
 
  Support for creating remote directories when uploading a file to a directory
  that does not exist on the server, just like --ftp-create-dirs.
 
 
 12. FILE
 
 12.1 Directory listing on non-POSIX
 
  Listing the contents of a directory accessed with FILE only works on
  platforms with opendir. Support could be added for more systems, like
  Windows.
 
 13. TLS
 
 13.1 TLS-PSK with OpenSSL
 
  Transport Layer Security pre-shared key ciphersuites (TLS-PSK) is a set of
  cryptographic protocols that provide secure communication based on pre-shared
  keys (PSKs). These pre-shared keys are symmetric keys shared in advance among
  the communicating parties.
 
  https://github.com/curl/curl/issues/5081
 
 13.2 TLS channel binding
 
  TLS 1.2 and 1.3 provide the ability to extract some secret data from the TLS
  connection and use it in the client request (usually in some sort of
  authentication) to ensure that the data sent is bound to the specific TLS
  connection and cannot be successfully intercepted by a proxy. This
  functionality can be used in a standard authentication mechanism such as
  GSS-API or SCRAM, or in custom approaches like custom HTTP Authentication
  headers.
 
  For TLS 1.2, the binding type is usually tls-unique, and for TLS 1.3 it is
  tls-exporter.
 
  https://datatracker.ietf.org/doc/html/rfc5929
  https://datatracker.ietf.org/doc/html/rfc9266
  https://github.com/curl/curl/issues/9226
 
 13.3 Defeat TLS fingerprinting
 
  By changing the order of TLS extensions provided in the TLS handshake, it is
  sometimes possible to circumvent TLS fingerprinting by servers. The TLS
  extension order is of course not the only way to fingerprint a client.
 
 13.4 Consider OCSP stapling by default
 
  Treat a negative response a reason for aborting the connection. Since OCSP
  stapling is presumed to get used much less in the future when Let's Encrypt
  drops the OCSP support, the benefit of this might however be limited.
 
  https://github.com/curl/curl/issues/15483
 
 13.5 Export session ids
 
  Add an interface to libcurl that enables "session IDs" to get
  exported/imported. Cris Bailiff said: "OpenSSL has functions which can
  serialise the current SSL state to a buffer of your choice, and recover/reset
  the state from such a buffer at a later date - this is used by mod_ssl for
  apache to implement and SSL session ID cache".
 
 13.6 Provide callback for cert verification
 
  OpenSSL supports a callback for customised verification of the peer
  certificate, but this does not seem to be exposed in the libcurl APIs. Could
  it be? There is so much that could be done if it were.
 
 13.7 Less memory massaging with Schannel
 
  The Schannel backend does a lot of custom memory management we would rather
  avoid: the repeated alloc + free in sends and the custom memory + realloc
  system for encrypted and decrypted data. That should be avoided and reduced
  for 1) efficiency and 2) safety.
 
 13.8 Support DANE
 
  DNS-Based Authentication of Named Entities (DANE) is a way to provide SSL
  keys and certs over DNS using DNSSEC as an alternative to the CA model.
  https://www.rfc-editor.org/rfc/rfc6698.txt
 
  An initial patch was posted by Suresh Krishnaswamy on March 7th 2013
  (https://curl.se/mail/lib-2013-03/0075.html) but it was a too simple
  approach. See Daniel's comments:
  https://curl.se/mail/lib-2013-03/0103.html . libunbound may be the
  correct library to base this development on.
 
  Björn Stenberg wrote a separate initial take on DANE that was never
  completed.
 
 13.9 TLS record padding
 
  TLS (1.3) offers optional record padding and OpenSSL provides an API for it.
  I could make sense for libcurl to offer this ability to applications to make
  traffic patterns harder to figure out by network traffic observers.
 
  See https://github.com/curl/curl/issues/5398
 
 13.10 Support Authority Information Access certificate extension (AIA)
 
  AIA can provide various things like CRLs but more importantly information
  about intermediate CA certificates that can allow validation path to be
  fulfilled when the HTTPS server does not itself provide them.
 
  Since AIA is about downloading certs on demand to complete a TLS handshake,
  it is probably a bit tricky to get done right.
 
  See https://github.com/curl/curl/issues/2793
 
 13.11 Some TLS options are not offered for HTTPS proxies
 
  Some TLS related options to the command line tool and libcurl are only
  provided for the server and not for HTTPS proxies. --proxy-tls-max,
  --proxy-tlsv1.3, --proxy-curves and a few more.
  For more Documentation on this see:
  https://curl.se/libcurl/c/tls-options.html
 
  https://github.com/curl/curl/issues/12286
 
 13.13 Make sure we forbid TLS 1.3 post-handshake authentication
 
  RFC 8740 explains how using HTTP/2 must forbid the use of TLS 1.3
  post-handshake authentication. We should make sure to live up to that.
 
  See https://github.com/curl/curl/issues/5396
 
 13.14 Support the clienthello extension
 
  Certain stupid networks and middle boxes have a problem with SSL handshake
  packets that are within a certain size range because how that sets some bits
  that previously (in older TLS version) were not set. The clienthello
  extension adds padding to avoid that size range.
 
  https://datatracker.ietf.org/doc/html/rfc7685
  https://github.com/curl/curl/issues/2299
 
 13.16 Share the CA cache
 
  For TLS backends that supports CA caching, it makes sense to allow the share
  object to be used to store the CA cache as well via the share API. Would
  allow multiple easy handles to reuse the CA cache and save themselves from a
  lot of extra processing overhead.
 
 13.17 Add missing features to TLS backends
 
  The feature matrix at https://curl.se/libcurl/c/tls-options.html shows which
  features are supported by which TLS backends, and thus also where there are
  feature gaps.
 
 14. Proxy
 
 14.1 Retry SOCKS handshake on address type not supported
 
  When curl resolves a hostname, it might get a mix of IPv6 and IPv4 returned.
  curl might then use an IPv6 address with a SOCKS5 proxy, which - if it does
  not support IPv6 - returns "Address type not supported" and curl exits with
  that error.
 
  Perhaps it is preferred if curl would in this situation instead first retry
  the SOCKS handshake again for this case and then use one of the IPv4
  addresses for the target host.
 
  See https://github.com/curl/curl/issues/17222
 
 15. Schannel
 
 15.1 Extend support for client certificate authentication
 
  The existing support for the -E/--cert and --key options could be
  extended by supplying a custom certificate and key in PEM format, see:
  - Getting a Certificate for Schannel
    https://msdn.microsoft.com/en-us/library/windows/desktop/aa375447.aspx
 
 15.2 Extend support for the --ciphers option
 
  The existing support for the --ciphers option could be extended
  by mapping the OpenSSL/GnuTLS cipher suites to the Schannel APIs, see
  - Specifying Schannel Ciphers and Cipher Strengths
    https://msdn.microsoft.com/en-us/library/windows/desktop/aa380161.aspx
 
 15.4 Add option to allow abrupt server closure
 
  libcurl with Schannel errors without a known termination point from the server
  (such as length of transfer, or SSL "close notify" alert) to prevent against
  a truncation attack. Really old servers may neglect to send any termination
  point. An option could be added to ignore such abrupt closures.
 
  https://github.com/curl/curl/issues/4427
 
 16. SASL
 
 16.1 Other authentication mechanisms
 
  Add support for other authentication mechanisms such as OLP,
  GSS-SPNEGO and others.
 
 16.2 Add QOP support to GSSAPI authentication
 
  Currently the GSSAPI authentication only supports the default QOP of auth
  (Authentication), whilst Kerberos V5 supports both auth-int (Authentication
  with integrity protection) and auth-conf (Authentication with integrity and
  privacy protection).
 
 
 17. SSH protocols
 
 17.1 Multiplexing
 
  SSH is a perfectly fine multiplexed protocols which would allow libcurl to do
  multiple parallel transfers from the same host using the same connection,
  much in the same spirit as HTTP/2 does. libcurl however does not take
  advantage of that ability but does instead always create a new connection for
  new transfers even if an existing connection already exists to the host.
 
  To fix this, libcurl would have to detect an existing connection and "attach"
  the new transfer to the existing one.
 
 17.2 Handle growing SFTP files
 
  The SFTP code in libcurl checks the file size *before* a transfer starts and
  then proceeds to transfer exactly that amount of data. If the remote file
  grows while the transfer is in progress libcurl does not notice and does not
  adapt. The OpenSSH SFTP command line tool does and libcurl could also just
  attempt to download more to see if there is more to get...
 
  https://github.com/curl/curl/issues/4344
 
 17.3 Read keys from ~/.ssh/id_ecdsa, id_ed25519
 
  The libssh2 backend in curl is limited to only reading keys from id_rsa and
  id_dsa, which makes it fail connecting to servers that use more modern key
  types.
 
  https://github.com/curl/curl/issues/8586
 
 17.4 Support CURLOPT_PREQUOTE
 
  The two other QUOTE options are supported for SFTP, but this was left out for
  unknown reasons.
 
 17.5 SSH over HTTPS proxy with more backends
 
  The SSH based protocols SFTP and SCP did not work over HTTPS proxy at
  all until PR https://github.com/curl/curl/pull/6021 brought the
  functionality with the libssh2 backend. Presumably, this support
  can/could be added for the other backends as well.
 
 17.6 SFTP with SCP://
 
  OpenSSH 9 switched their 'scp' tool to speak SFTP under the hood. Going
  forward it might be worth having curl or libcurl attempt SFTP if SCP fails to
  follow suite.
 
 18. Command line tool
 
 18.1 sync
 
  "curl --sync http://example.com/feed[1-100].rss" or
  "curl --sync http://example.net/{index,calendar,history}.html"
 
  Downloads a range or set of URLs using the remote name, but only if the
  remote file is newer than the local file. A Last-Modified HTTP date header
  should also be used to set the mod date on the downloaded file.
 
 18.2 glob posts
 
  Globbing support for -d and -F, as in 'curl -d "name=foo[0-9]" URL'.
  This is easily scripted though.
 
 18.4 --proxycommand
 
  Allow the user to make curl run a command and use its stdio to make requests
  and not do any network connection by itself. Example:
 
    curl --proxycommand 'ssh pi@raspberrypi.local -W 10.1.1.75 80' \
         http://some/otherwise/unavailable/service.php
 
  See https://github.com/curl/curl/issues/4941
 
 18.5 UTF-8 filenames in Content-Disposition
 
  RFC 6266 documents how UTF-8 names can be passed to a client in the
  Content-Disposition header, and curl does not support this.
 
  https://github.com/curl/curl/issues/1888
 
 18.6 Option to make -Z merge lined based outputs on stdout
 
  When a user requests multiple lined based files using -Z and sends them to
  stdout, curl does not "merge" and send complete lines fine but may send
  partial lines from several sources.
 
  https://github.com/curl/curl/issues/5175
 
 18.7 specify which response codes that make -f/--fail return error
 
  Allows a user to better specify exactly which error code(s) that are fine
  and which are errors for their specific uses cases
 
 18.9 Choose the name of file in braces for complex URLs
 
  When using braces to download a list of URLs and you use complicated names
  in the list of alternatives, it could be handy to allow curl to use other
  names when saving.
 
  Consider a way to offer that. Possibly like
  {partURL1:name1,partURL2:name2,partURL3:name3} where the name following the
  colon is the output name.
 
  See https://github.com/curl/curl/issues/221
 
 18.10 improve how curl works in a Windows console window
 
  If you pull the scrollbar when transferring with curl in a Windows console
  window, the transfer is interrupted and can get disconnected. This can
  probably be improved. See https://github.com/curl/curl/issues/322
 
 18.11 Windows: set attribute 'archive' for completed downloads
 
  The archive bit (FILE_ATTRIBUTE_ARCHIVE, 0x20) separates files that shall be
  backed up from those that are either not ready or have not changed.
 
  Downloads in progress are neither ready to be backed up, nor should they be
  opened by a different process. Only after a download has been completed it is
  sensible to include it in any integer snapshot or backup of the system.
 
  See https://github.com/curl/curl/issues/3354
 
 18.12 keep running, read instructions from pipe/socket
 
  Provide an option that makes curl not exit after the last URL (or even work
  without a given URL), and then make it read instructions passed on a pipe or
  over a socket to make further instructions so that a second subsequent curl
  invoke can talk to the still running instance and ask for transfers to get
  done, and thus maintain its connection pool, DNS cache and more.
 
 18.13 Acknowledge Ratelimit headers
 
  Consider a command line option that can make curl do multiple serial requests
  while acknowledging server specified rate limits:
  https://datatracker.ietf.org/doc/draft-ietf-httpapi-ratelimit-headers/
 
  See https://github.com/curl/curl/issues/5406
 
 18.14 --dry-run
 
  A command line option that makes curl show exactly what it would do and send
  if it would run for real.
 
  See https://github.com/curl/curl/issues/5426
 
 18.15 --retry should resume
 
  When --retry is used and curl actually retries transfer, it should use the
  already transferred data and do a resumed transfer for the rest (when
  possible) so that it does not have to transfer the same data again that was
  already transferred before the retry.
 
  See https://github.com/curl/curl/issues/1084
 
 18.17 consider filename from the redirected URL with -O ?
 
  When a user gives a URL and uses -O, and curl follows a redirect to a new
  URL, the filename is not extracted and used from the newly redirected-to URL
  even if the new URL may have a much more sensible filename.
 
  This is clearly documented and helps for security since there is no surprise
  to users which filename that might get overwritten, but maybe a new option
  could allow for this or maybe -J should imply such a treatment as well as -J
  already allows for the server to decide what filename to use so it already
  provides the "may overwrite any file" risk.
 
  This is extra tricky if the original URL has no filename part at all since
  then the current code path does error out with an error message, and we
  cannot *know* already at that point if curl is redirected to a URL that has a
  filename...
 
  See https://github.com/curl/curl/issues/1241
 
 18.18 retry on network is unreachable
 
  The --retry option retries transfers on "transient failures". We later added
  --retry-connrefused to also retry for "connection refused" errors.
 
  Suggestions have been brought to also allow retry on "network is unreachable"
  errors and while totally reasonable, maybe we should consider a way to make
  this more configurable than to add a new option for every new error people
  want to retry for?
 
  https://github.com/curl/curl/issues/1603
 
 18.19 expand ~/ in config files
 
  For example .curlrc could benefit from being able to do this.
 
  See https://github.com/curl/curl/issues/2317
 
 18.20 hostname sections in config files
 
  config files would be more powerful if they could set different
  configurations depending on used URLs, hostname or possibly origin. Then a
  default .curlrc could a specific user-agent only when doing requests against
  a certain site.
 
 18.21 retry on the redirected-to URL
 
  When curl is told to --retry a failed transfer and follows redirects, it
  might get an HTTP 429 response from the redirected-to URL and not the
  original one, which then could make curl decide to rather retry the transfer
  on that URL only instead of the original operation to the original URL.
 
  Perhaps extra emphasized if the original transfer is a large POST that
  redirects to a separate GET, and that GET is what gets the 529
 
  See https://github.com/curl/curl/issues/5462
 
 18.23 Set the modification date on an uploaded file
 
  For SFTP and possibly FTP, curl could offer an option to set the
  modification time for the uploaded file.
 
  See https://github.com/curl/curl/issues/5768
 
 18.24 Use multiple parallel transfers for a single download
 
  To enhance transfer speed, downloading a single URL can be split up into
  multiple separate range downloads that get combined into a single final
  result.
 
  An ideal implementation would not use a specified number of parallel
  transfers, but curl could:
  - First start getting the full file as transfer A
  - If after N seconds have passed and the transfer is expected to continue for
    M seconds or more, add a new transfer (B) that asks for the second half of
    A's content (and stop A at the middle).
  - If splitting up the work improves the transfer rate, it could then be done
    again. Then again, etc up to a limit.
 
  This way, if transfer B fails (because Range: is not supported) it lets
  transfer A remain the single one. N and M could be set to some sensible
  defaults.
 
  See https://github.com/curl/curl/issues/5774
 
 18.25 Prevent terminal injection when writing to terminal
 
  curl could offer an option to make escape sequence either non-functional or
  avoid cursor moves or similar to reduce the risk of a user getting tricked by
  clever tricks.
 
  See https://github.com/curl/curl/issues/6150
 
 18.26 Custom progress meter update interval
 
  Users who are for example doing large downloads in CI or remote setups might
  want the occasional progress meter update to see that the transfer is
  progressing and has not stuck, but they may not appreciate the
  many-times-a-second frequency curl can end up doing it with now.
 
 18.27 -J and -O with %-encoded filenames
 
  -J/--remote-header-name does not decode %-encoded filenames. RFC 6266 details
  how it should be done. The can of worm is basically that we have no charset
  handling in curl and ASCII >=128 is a challenge for us. Not to mention that
  decoding also means that we need to check for nastiness that is attempted,
  like "../" sequences and the like. Probably everything to the left of any
  embedded slashes should be cut off.
  https://curl.se/bug/view.cgi?id=1294
 
  -O also does not decode %-encoded names, and while it has even less
  information about the charset involved the process is similar to the -J case.
 
  Note that we do not decode -O without the user asking for it with some other
  means, since -O has always been documented to use the name exactly as
  specified in the URL.
 
 18.28 -J with -C -
 
  When using -J (with -O), automatically resumed downloading together with "-C
  -" fails. Without -J the same command line works. This happens because the
  resume logic is worked out before the target filename (and thus its
  pre-transfer size) has been figured out. This can be improved.
 
  https://curl.se/bug/view.cgi?id=1169
 
 18.29 --retry and transfer timeouts
 
  If using --retry and the transfer timeouts (possibly due to using -m or
  -y/-Y) the next attempt does not resume the transfer properly from what was
  downloaded in the previous attempt but truncates and restarts at the original
  position where it was at before the previous failed attempt. See
  https://curl.se/mail/lib-2008-01/0080.html and Mandriva bug report
  https://qa.mandriva.com/show_bug.cgi?id=22565
 
 
 19. Build
 
 19.2 Enable PIE and RELRO by default
 
  Especially when having programs that execute curl via the command line, PIE
  renders the exploitation of memory corruption vulnerabilities a lot more
  difficult. This can be attributed to the additional information leaks being
  required to conduct a successful attack. RELRO, on the other hand, masks
  different binary sections like the GOT as read-only and thus kills a handful
  of techniques that come in handy when attackers are able to arbitrarily
  overwrite memory. A few tests showed that enabling these features had close
  to no impact, neither on the performance nor on the general functionality of
  curl.
 
 19.3 Do not use GNU libtool on OpenBSD
 
  When compiling curl on OpenBSD with "--enable-debug" it gives linking errors
  when you use GNU libtool. This can be fixed by using the libtool provided by
  OpenBSD itself. However for this the user always needs to invoke make with
  "LIBTOOL=/usr/bin/libtool". It would be nice if the script could have some
  magic to detect if this system is an OpenBSD host and then use the OpenBSD
  libtool instead.
 
  See https://github.com/curl/curl/issues/5862
 
 19.4 Package curl for Windows in a signed installer
 
  See https://github.com/curl/curl/issues/5424
 
 19.5 make configure use --cache-file more and better
 
  The configure script can be improved to cache more values so that repeated
  invokes run much faster.
 
  See https://github.com/curl/curl/issues/7753
 
 20. Test suite
 
 20.1 SSL tunnel
 
  Make our own version of stunnel for simple port forwarding to enable HTTPS
  and FTP-SSL tests without the stunnel dependency, and it could allow us to
  provide test tools built with either OpenSSL or GnuTLS
 
 20.2 more protocols supported
 
  Extend the test suite to include more protocols. The telnet could just do FTP
  or http operations (for which we have test servers).
 
 20.3 more platforms supported
 
  Make the test suite work on more platforms. OpenBSD and macOS. Remove
  fork()s and it should become even more portable.
 
 20.4 write an SMB test server to replace impacket
 
  This would allow us to run SMB tests on more platforms and do better and more
  covering tests.
 
  See https://github.com/curl/curl/issues/15697
 
 20.5 Use the RFC 6265 test suite
 
  A test suite made for HTTP cookies (RFC 6265) by Adam Barth is available at
  https://github.com/abarth/http-state/tree/master/tests
 
  It would be good if someone would write a script/setup that would run curl
  with that test suite and detect deviances. Ideally, that would even be
  incorporated into our regular test suite.
 
 20.6 Run web-platform-tests URL tests
 
  Run web-platform-tests URL tests and compare results with browsers on wpt.fyi
 
  It would help us find issues to fix and help us document where our parser
  differs from the WHATWG URL spec parsers.
 
  See https://github.com/curl/curl/issues/4477
 
 21. MQTT
 
 21.1 Support rate-limiting
 
  The rate-limiting logic is done in the PERFORMING state in multi.c but MQTT
  is not (yet) implemented to use that.
 
 21.2 Support MQTTS
 
 21.3 Handle network blocks
 
   Running test suite with
   `CURL_DBG_SOCK_WBLOCK=90 ./runtests.pl -a mqtt` makes several
   MQTT test cases fail where they should not.
 
 22. TFTP
 
 22.1 TFTP does not convert LF to CRLF for mode=netascii
 
  RFC 3617 defines that an TFTP transfer can be done using "netascii"
  mode. curl does not support extracting that mode from the URL nor does it treat
  such transfers specifically. It should probably do LF to CRLF translations
  for them.
 
  See https://github.com/curl/curl/issues/12655
 
 23. Gopher
 
 23.1 Handle network blocks
 
   Running test suite with
   `CURL_DBG_SOCK_WBLOCK=90 ./runtests.pl -a 1200 to 1300` makes several
   Gopher test cases fail where they should not.