2
0

SSL_COMP_add_compression_method.pod 3.5 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107
  1. =pod
  2. =head1 NAME
  3. SSL_COMP_add_compression_method, SSL_COMP_get_compression_methods,
  4. SSL_COMP_get0_name, SSL_COMP_get_id, SSL_COMP_free_compression_methods
  5. - handle SSL/TLS integrated compression methods
  6. =head1 SYNOPSIS
  7. #include <openssl/ssl.h>
  8. int SSL_COMP_add_compression_method(int id, COMP_METHOD *cm);
  9. STACK_OF(SSL_COMP) *SSL_COMP_get_compression_methods(void);
  10. const char *SSL_COMP_get0_name(const SSL_COMP *comp);
  11. int SSL_COMP_get_id(const SSL_COMP *comp);
  12. Deprecated:
  13. #if OPENSSL_API_COMPAT < 0x10100000L
  14. void SSL_COMP_free_compression_methods(void)
  15. #endif
  16. =head1 DESCRIPTION
  17. SSL_COMP_add_compression_method() adds the compression method B<cm> with
  18. the identifier B<id> to the list of available compression methods. This
  19. list is globally maintained for all SSL operations within this application.
  20. It cannot be set for specific SSL_CTX or SSL objects.
  21. SSL_COMP_get_compression_methods() returns a stack of all of the available
  22. compression methods or NULL on error.
  23. SSL_COMP_get0_name() returns the name of the compression method B<comp>.
  24. SSL_COMP_get_id() returns the id of the compression method B<comp>.
  25. SSL_COMP_free_compression_methods() releases any resources acquired to
  26. maintain the internal table of compression methods.
  27. =head1 NOTES
  28. The TLS standard (or SSLv3) allows the integration of compression methods
  29. into the communication. The TLS RFC does however not specify compression
  30. methods or their corresponding identifiers, so there is currently no compatible
  31. way to integrate compression with unknown peers. It is therefore currently not
  32. recommended to integrate compression into applications. Applications for
  33. non-public use may agree on certain compression methods. Using different
  34. compression methods with the same identifier will lead to connection failure.
  35. An OpenSSL client speaking a protocol that allows compression (SSLv3, TLSv1)
  36. will unconditionally send the list of all compression methods enabled with
  37. SSL_COMP_add_compression_method() to the server during the handshake.
  38. Unlike the mechanisms to set a cipher list, there is no method available to
  39. restrict the list of compression method on a per connection basis.
  40. An OpenSSL server will match the identifiers listed by a client against
  41. its own compression methods and will unconditionally activate compression
  42. when a matching identifier is found. There is no way to restrict the list
  43. of compression methods supported on a per connection basis.
  44. If enabled during compilation, the OpenSSL library will have the
  45. COMP_zlib() compression method available.
  46. =head1 RETURN VALUES
  47. SSL_COMP_add_compression_method() may return the following values:
  48. =over 4
  49. =item Z<>0
  50. The operation succeeded.
  51. =item Z<>1
  52. The operation failed. Check the error queue to find out the reason.
  53. =back
  54. SSL_COMP_get_compression_methods() returns the stack of compressions methods or
  55. NULL on error.
  56. SSL_COMP_get0_name() returns the name of the compression method or NULL on error.
  57. SSL_COMP_get_id() returns the name of the compression method or -1 on error.
  58. =head1 SEE ALSO
  59. L<ssl(7)>
  60. =head1 HISTORY
  61. SSL_COMP_free_compression_methods() was deprecated in OpenSSL 1.1.0;
  62. do not use it.
  63. SSL_COMP_get0_name() and SSL_comp_get_id() were added in OpenSSL 1.1.0d.
  64. =head1 COPYRIGHT
  65. Copyright 2001-2016 The OpenSSL Project Authors. All Rights Reserved.
  66. Licensed under the OpenSSL license (the "License"). You may not use
  67. this file except in compliance with the License. You can obtain a copy
  68. in the file LICENSE in the source distribution or at
  69. L<https://www.openssl.org/source/license.html>.
  70. =cut