access internal session cache
struct lhash_st *SSL_CTX_sessions(SSL_CTX *ctx);
SSL_CTX_sessions() returns a pointer to the lhash databases containing the
internal session cache for ctx.
The sessions in the internal session cache are kept in an
(3) type database. It is possible to directly
access this database e.g. for searching. In parallel, the sessions
form a linked list which is maintained separately from the
(3) operations, so that the database must not be
modified directly but by using the
(3) family of functions.