=pod=head1 NAMESSL - OpenSSL SSL/TLS library=head1 SYNOPSIS=head1 DESCRIPTIONThe OpenSSL B<ssl> library implements the Secure Sockets Layer (SSL v2/v3) andTransport Layer Security (TLS v1) protocols. It provides a rich API which isdocumented here.=head1 HEADER FILESCurrently the OpenSSL B<ssl> library provides the following C header filescontaining the prototypes for the data structures and and functions:=over 4=item B<ssl.h>That's the common header file for the SSL/TLS API.  Include it into yourprogram to make the API of the B<ssl> library available. It internallyincludes both more private SSL headers and headers from the B<crypto> library.Whenever you need hard-core details on the internals of the SSL API, lookinside this header file.=item B<ssl2.h>That's the sub header file dealing with the SSLv2 protocol only.I<Usually you don't have to include it explicitly becauseit's already included by ssl.h>.=item B<ssl3.h>That's the sub header file dealing with the SSLv3 protocol only.I<Usually you don't have to include it explicitly becauseit's already included by ssl.h>.=item B<ssl23.h>That's the sub header file dealing with the combined use of the SSLv2 andSSLv3 protocols.I<Usually you don't have to include it explicitly becauseit's already included by ssl.h>.=item B<tls1.h>That's the sub header file dealing with the TLSv1 protocol only.I<Usually you don't have to include it explicitly becauseit's already included by ssl.h>.=back=head1 DATA STRUCTURESCurrently the OpenSSL B<ssl> library functions deals with the following datastructures:=over 4=item B<SSL_METHOD> (SSL Method)That's a dispatch structure describing the internal B<ssl> librarymethods/functions which implement the various protocol versions (SSLv1, SSLv2and TLSv1). It's needed to create an B<SSL_CTX>.=item B<SSL_CIPHER> (SSL Cipher)This structure holds the algorithm information for a particular cipher whichare a core part of the SSL/TLS protocol. The available ciphers are configuredon a B<SSL_CTX> basis and the actually used ones are then part of theB<SSL_SESSION>.=item B<SSL_CTX> (SSL Context)That's the global context structure which is created by a server or clientonce per program life-time and which holds mainly default values for theB<SSL> structures which are later created for the connections.=item B<SSL_SESSION> (SSL Session)This is a structure containing the current TLS/SSL session details for aconnection: B<SSL_CIPHER>s, client and server certificates, keys, etc.=item B<SSL> (SSL Connection)That's the main SSL/TLS structure which is created by a server or client perestablished connection. This actually is the core structure in the SSL API.Under run-time the application usually deals with this structure which haslinks to mostly all other structures.=back=head1 API FUNCTIONSCurrently the OpenSSL B<ssl> library exports 214 API functions.They are documented in the following:=head2 DEALING WITH PROTOCOL METHODSHere we document the various API functions which deal with the SSL/TLSprotocol methods defined in B<SSL_METHOD> structures.=over 4=item SSL_METHOD *B<SSLv2_client_method>(void);Constructor for the SSLv2 SSL_METHOD structure for a dedicated client.=item SSL_METHOD *B<SSLv2_server_method>(void);Constructor for the SSLv2 SSL_METHOD structure for a dedicated server.=item SSL_METHOD *B<SSLv2_method>(void);Constructor for the SSLv2 SSL_METHOD structure for combined client and server.=item SSL_METHOD *B<SSLv3_client_method>(void);Constructor for the SSLv3 SSL_METHOD structure for a dedicated client.=item SSL_METHOD *B<SSLv3_server_method>(void);Constructor for the SSLv3 SSL_METHOD structure for a dedicated server.=item SSL_METHOD *B<SSLv3_method>(void);Constructor for the SSLv3 SSL_METHOD structure for combined client and server.=item SSL_METHOD *B<TLSv1_client_method>(void);Constructor for the TLSv1 SSL_METHOD structure for a dedicated client.=item SSL_METHOD *B<TLSv1_server_method>(void);Constructor for the TLSv1 SSL_METHOD structure for a dedicated server.=item SSL_METHOD *B<TLSv1_method>(void);Constructor for the TLSv1 SSL_METHOD structure for combined client and server.=back=head2 DEALING WITH CIPHERSHere we document the various API functions which deal with the SSL/TLSciphers defined in B<SSL_CIPHER> structures.=over 4=item char *B<SSL_CIPHER_description>(SSL_CIPHER *cipher, char *buf, int len);Write a string to I<buf> (with a maximum size of I<len>) containing a humanreadable description of I<cipher>. Returns I<buf>.=item int B<SSL_CIPHER_get_bits>(SSL_CIPHER *cipher, int *alg_bits);Determine the number of bits in I<cipher>. Because of export crippled ciphersthere are two bits: The bits the algorithm supports in general (stored toI<alg_bits>) and the bits which are actually used (the return value).=item const char *B<SSL_CIPHER_get_name>(SSL_CIPHER *cipher);Return the internal name of I<cipher> as a string. These are the variousstrings defined by the I<SSL2_TXT_xxx>, I<SSL3_TXT_xxx> and I<TLS1_TXT_xxx>definitions in the header files.=item char *B<SSL_CIPHER_get_version>(SSL_CIPHER *cipher);Returns a string like "C<TLSv1/SSLv3>" or "C<SSLv2>" which indicates theSSL/TLS protocol version to which I<cipher> belongs (i.e. where it was definedin the specification the first time).=back=head2 DEALING WITH PROTOCOL CONTEXTSHere we document the various API functions which deal with the SSL/TLSprotocol context defined in the B<SSL_CTX> structure.=over 4=item int B<SSL_CTX_add_client_CA>(SSL_CTX *ctx, X509 *x);=item long B<SSL_CTX_add_extra_chain_cert>(SSL_CTX *ctx, X509 *x509);=item int B<SSL_CTX_add_session>(SSL_CTX *ctx, SSL_SESSION *c);=item int B<SSL_CTX_check_private_key>(SSL_CTX *ctx);=item long B<SSL_CTX_ctrl>(SSL_CTX *ctx, int cmd, long larg, char *parg);=item void B<SSL_CTX_flush_sessions>(SSL_CTX *s, long t);=item void B<SSL_CTX_free>(SSL_CTX *a);=item char *B<SSL_CTX_get_app_data>(SSL_CTX *ctx);=item X509_STORE *B<SSL_CTX_get_cert_store>(SSL_CTX *ctx);=item STACK *B<SSL_CTX_get_client_CA_list>(SSL_CTX *ctx);=item int (*B<SSL_CTX_get_client_cert_cb>(SSL_CTX *ctx))(SSL *ssl, X509 **x509, EVP_PKEY **pkey);=item char *B<SSL_CTX_get_ex_data>(SSL_CTX *s, int idx);=item int B<SSL_CTX_get_ex_new_index>(long argl, char *argp, int (*new_func);(void), int (*dup_func)(void), void (*free_func)(void))=item void (*B<SSL_CTX_get_info_callback>(SSL_CTX *ctx))(SSL *ssl, int cb, int ret);=item int B<SSL_CTX_get_quiet_shutdown>(SSL_CTX *ctx);=item int B<SSL_CTX_get_session_cache_mode>(SSL_CTX *ctx);=item long B<SSL_CTX_get_timeout>(SSL_CTX *ctx);=item int (*B<SSL_CTX_get_verify_callback>(SSL_CTX *ctx))(int ok, X509_STORE_CTX *ctx);=item int B<SSL_CTX_get_verify_mode>(SSL_CTX *ctx);=item int B<SSL_CTX_load_verify_locations>(SSL_CTX *ctx, char *CAfile, char *CApath);=item long B<SSL_CTX_need_tmp_RSA>(SSL_CTX *ctx);=item SSL_CTX *B<SSL_CTX_new>(SSL_METHOD *meth);=item int B<SSL_CTX_remove_session>(SSL_CTX *ctx, SSL_SESSION *c);=item int B<SSL_CTX_sess_accept>(SSL_CTX *ctx);=item int B<SSL_CTX_sess_accept_good>(SSL_CTX *ctx);=item int B<SSL_CTX_sess_accept_renegotiate>(SSL_CTX *ctx);=item int B<SSL_CTX_sess_cache_full>(SSL_CTX *ctx);=item int B<SSL_CTX_sess_cb_hits>(SSL_CTX *ctx);=item int B<SSL_CTX_sess_connect>(SSL_CTX *ctx);=item int B<SSL_CTX_sess_connect_good>(SSL_CTX *ctx);=item int B<SSL_CTX_sess_connect_renegotiate>(SSL_CTX *ctx);=item int B<SSL_CTX_sess_get_cache_size>(SSL_CTX *ctx);=item SSL_SESSION *(*B<SSL_CTX_sess_get_get_cb>(SSL_CTX *ctx))(SSL *ssl, unsigned char *data, int len, int *copy);=item int (*B<SSL_CTX_sess_get_new_cb>(SSL_CTX *ctx)(SSL *ssl, SSL_SESSION *sess);=item void (*B<SSL_CTX_sess_get_remove_cb>(SSL_CTX *ctx)(SSL_CTX *ctx, SSL_SESSION *sess);=item int B<SSL_CTX_sess_hits>(SSL_CTX *ctx);=item int B<SSL_CTX_sess_misses>(SSL_CTX *ctx);=item int B<SSL_CTX_sess_number>(SSL_CTX *ctx);=item void B<SSL_CTX_sess_set_cache_size>(SSL_CTX *ctx,t);=item void B<SSL_CTX_sess_set_get_cb>(SSL_CTX *ctx, SSL_SESSION *(*cb)(SSL *ssl, unsigned char *data, int len, int *copy));=item void B<SSL_CTX_sess_set_new_cb>(SSL_CTX *ctx, int (*cb)(SSL *ssl, SSL_SESSION *sess));=item void B<SSL_CTX_sess_set_remove_cb>(SSL_CTX *ctx, void (*cb)(SSL_CTX *ctx, SSL_SESSION *sess));=item int B<SSL_CTX_sess_timeouts>(SSL_CTX *ctx);=item LHASH *B<SSL_CTX_sessions>(SSL_CTX *ctx);=item void B<SSL_CTX_set_app_data>(SSL_CTX *ctx, void *arg);=item void B<SSL_CTX_set_cert_store>(SSL_CTX *ctx, X509_STORE *cs);=item void B<SSL_CTX_set_cert_verify_cb>(SSL_CTX *ctx, int (*cb)(SSL_CTX *), char *arg)=item int B<SSL_CTX_set_cipher_list>(SSL_CTX *ctx, char *str);=item void B<SSL_CTX_set_client_CA_list>(SSL_CTX *ctx, STACK *list);=item void B<SSL_CTX_set_client_cert_cb>(SSL_CTX *ctx, int (*cb)(SSL *ssl, X509 **x509, EVP_PKEY **pkey));=item void B<SSL_CTX_set_default_passwd_cb>(SSL_CTX *ctx, int (*cb);(void))=item void B<SSL_CTX_set_default_read_ahead>(SSL_CTX *ctx, int m);=item int B<SSL_CTX_set_default_verify_paths>(SSL_CTX *ctx);=item int B<SSL_CTX_set_ex_data>(SSL_CTX *s, int idx, char *arg);=item void B<SSL_CTX_set_info_callback>(SSL_CTX *ctx, void (*cb)(SSL *ssl, int cb, int ret));=item void B<SSL_CTX_set_options>(SSL_CTX *ctx, unsigned long op);=item void B<SSL_CTX_set_quiet_shutdown>(SSL_CTX *ctx, int mode);=item void B<SSL_CTX_set_session_cache_mode>(SSL_CTX *ctx, int mode);=item int B<SSL_CTX_set_ssl_version>(SSL_CTX *ctx, SSL_METHOD *meth);=item void B<SSL_CTX_set_timeout>(SSL_CTX *ctx, long t);=item long B<SSL_CTX_set_tmp_dh>(SSL_CTX* ctx, DH *dh);=item long B<SSL_CTX_set_tmp_dh_callback>(SSL_CTX *ctx, DH *(*cb)(void));=item long B<SSL_CTX_set_tmp_rsa>(SSL_CTX *ctx, RSA *rsa);=item SSL_CTX_set_tmp_rsa_callbackC<long B<SSL_CTX_set_tmp_rsa_callback>(SSL_CTX *B<ctx>, RSA *(*B<cb>)(SSL *B<ssl>, int B<export>, int B<keylength>));>Sets the callback which will be called when a temporary private key isrequired. The B<C<export>> flag will be set if the reason for needinga temp key is that an export ciphersuite is in use, in which case,B<C<keylength>> will contain the required keylength in bits. Generate a key ofappropriate size (using ???) and return it.=item SSL_set_tmp_rsa_callbacklong B<SSL_set_tmp_rsa_callback>(SSL *ssl, RSA *(*cb)(SSL *ssl, int export, int keylength));