BIO_s_connect() returns the connect BIO method. This is a wrapper round the platform's TCP/IP socket connection routines.Using connect BIOs, TCP/IP connections can be made and data transferred using only BIO routines. In this way any platform specific operations are hidden by the BIO abstraction.
Read and write operations on a connect BIO will perform I/O on the underlying connection. If no connection is established and the port and hostname (see below) is set up properly then a connection is established first.
Connect BIOs support BIO_puts() but not BIO_gets().
If the close flag is set on a connect BIO then any active connection is shutdown and the socket closed when the BIO is freed.
Calling BIO_reset() on a connect BIO will close any active connection and reset the BIO into a state where it can connect to the same host again.
BIO_get_fd() places the underlying socket in c if it is not NULL, it also returns the socket . If c is not NULL it should be of type (int *).
BIO_set_conn_hostname() uses the string name to set the hostname. The hostname can be an IP address. The hostname can also include the port in the form hostname:port . It is also acceptable to use the form "hostname/any/other/path" or "hostname:port/any/other/path".
BIO_set_conn_port() sets the port to port. port can be the numerical form or a string such as "http". A string will be looked up first using getservbyname() on the host platform but if that fails a standard table of port names will be used. Currently the list is http, telnet, socks, https, ssl, ftp, gopher and wais.
BIO_set_conn_ip() sets the IP address to ip using binary form, that is four bytes specifying the IP address in big-endian form.
BIO_set_conn_int_port() sets the port using port. port should be of type (int *).
BIO_get_conn_hostname() returns the hostname of the connect BIO or NULL if the BIO is initialized but no hostname is set. This return value is an internal pointer which should not be modified.
BIO_get_conn_port() returns the port as a string.
BIO_get_conn_ip() returns the IP address in binary form.
BIO_get_conn_int_port() returns the port as an int.
BIO_set_nbio() sets the non blocking I/O flag to n. If n is zero then blocking I/O is set. If n is 1 then non blocking I/O is set. Blocking I/O is the default. The call to BIO_set_nbio() should be made before the connection is established because non blocking I/O is set during the connect process.
BIO_new_connect() combines BIO_new() and BIO_set_conn_hostname() into a single call: that is it creates a new connect BIO with name.
BIO_do_connect() attempts to connect the supplied BIO. It returns 1 if the connection was established successfully. A zero or negative value is returned if the connection could not be established, the call BIO_should_retry() should be used for non blocking connect BIOs to determine if the call should be retried.