SSL_COMP_add_compression_method(3)

     SSL_COMP_add_compressio0<I>..9.6ho(SSL_COMP_add_compression_method(3)

     NAME
          SSL_COMP_add_compression_method - handle SSL/TLS integrated
          compression methods

     SYNOPSIS
           #include <openssl/ssl.h>

           int SSL_COMP_add_compression_method(int id, COMP_METHOD *cm);

     DESCRIPTION
          SSL_COMP_add_compression_method() adds the compression
          method cm with the identifier id to the list of available
          compression methods. This list is globally maintained for
          all SSL operations within this application.  It cannot be
          set for specific SSL_CTX or SSL objects.

     NOTES
          The TLS standard (or SSLv3) allows the integration of
          compression methods into the communication. The TLS RFC does
          however not specify compression methods or their
          corresponding identifiers, so there is currently no
          compatible way to integrate compression with unknown peers.
          It is therefore currently not recommended to integrate
          compression into applications. Applications for non-public
          use may agree on certain compression methods. Using
          different compression methods with the same identifier will
          lead to connection failure.

          An OpenSSL client speaking a protocol that allows
          compression (SSLv3, TLSv1) will unconditionally send the
          list of all compression methods enabled with
          SSL_COMP_add_compression_method() to the server during the
          handshake.  Unlike the mechanisms to set a cipher list,
          there is no method available to restrict the list of
          compression method on a per connection basis.

          An OpenSSL server will match the identifiers listed by a
          client against its own compression methods and will
          unconditionally activate compression when a matching
          identifier is found. There is no way to restrict the list of
          compression methods supported on a per connection basis.

          The OpenSSL library has the compression methods CCOOMMPP_rrllee(())
          and (when especially enabled during compilation) CCOOMMPP_zzlliibb(())
          available.

     WARNINGS
          Once the identities of the compression methods for the TLS
          protocol have been standardized, the compression API will
          most likely be changed. Using it in the current state is not
          recommended.

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     SSL_COMP_add_compressio0<I>..9.6ho(SSL_COMP_add_compression_method(3)

     RETURN VALUES
          SSL_COMP_add_compression_method() may return the following
          values:

          1   The operation succeeded.

          o   The operation failed. Check the error queue to find out
              the reason.

     SEE ALSO
          ssl(3)

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