BIO_s_connect(3) OpenSSL BIO_s_connect(3) NNAAMMEE BIO_s_connect, BIO_new_connect, BIO_set_conn_hostname, BIO_set_conn_port, BIO_set_conn_ip, BIO_set_conn_int_port, BIO_get_conn_hostname, BIO_get_conn_port, BIO_get_conn_ip, BIO_get_conn_int_port, BIO_set_nbio, BIO_do_connect - connect BIO SSYYNNOOPPSSIISS #include BIO_METHOD * BIO_s_connect(void); BIO *BIO_new_connect(char *name); long BIO_set_conn_hostname(BIO *b, char *name); long BIO_set_conn_port(BIO *b, char *port); long BIO_set_conn_ip(BIO *b, char *ip); long BIO_set_conn_int_port(BIO *b, char *port); char *BIO_get_conn_hostname(BIO *b); char *BIO_get_conn_port(BIO *b); char *BIO_get_conn_ip(BIO *b); long BIO_get_conn_int_port(BIO *b); long BIO_set_nbio(BIO *b, long n); int BIO_do_connect(BIO *b); DDEESSCCRRIIPPTTIIOONN _B_I_O___s___c_o_n_n_e_c_t_(_) 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 estab- lished first. Connect BIOs support _B_I_O___p_u_t_s_(_) but not _B_I_O___g_e_t_s_(_). 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 _B_I_O___r_e_s_e_t_(_) 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. _B_I_O___g_e_t___f_d_(_) places the underlying socket in cc if it is not NULL, it also returns the socket . If cc is not NULL it should be of type (int *). _B_I_O___s_e_t___c_o_n_n___h_o_s_t_n_a_m_e_(_) uses the string nnaammee 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". _B_I_O___s_e_t___c_o_n_n___p_o_r_t_(_) sets the port to ppoorrtt. ppoorrtt can be the numerical form or a string such as "http". A string will be looked up first using _g_e_t_s_e_r_v_b_y_n_a_m_e_(_) 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. _B_I_O___s_e_t___c_o_n_n___i_p_(_) sets the IP address to iipp using binary form, that is four bytes specifying the IP address in big-endian form. _B_I_O___s_e_t___c_o_n_n___i_n_t___p_o_r_t_(_) sets the port using ppoorrtt. ppoorrtt should be of type (int *). _B_I_O___g_e_t___c_o_n_n___h_o_s_t_n_a_m_e_(_) 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. _B_I_O___g_e_t___c_o_n_n___p_o_r_t_(_) returns the port as a string. _B_I_O___g_e_t___c_o_n_n___i_p_(_) returns the IP address in binary form. _B_I_O___g_e_t___c_o_n_n___i_n_t___p_o_r_t_(_) returns the port as an int. _B_I_O___s_e_t___n_b_i_o_(_) sets the non blocking I/O flag to nn. If nn is zero then blocking I/O is set. If nn is 1 then non blocking I/O is set. Blocking I/O is the default. The call to _B_I_O___s_e_t___n_b_i_o_(_) should be made before the connection is established because non blocking I/O is set during the connect process. _B_I_O___n_e_w___c_o_n_n_e_c_t_(_) combines _B_I_O___n_e_w_(_) and _B_I_O___s_e_t___c_o_n_n___h_o_s_t_n_a_m_e_(_) into a single call: that is it creates a new connect BIO with nnaammee. _B_I_O___d_o___c_o_n_n_e_c_t_(_) 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 _B_I_O___s_h_o_u_l_d___r_e_t_r_y_(_) should be used for non blocking connect BIOs to determine if the call should be retried. NNOOTTEESS If blocking I/O is set then a non positive return value from any I/O call is caused by an error condition, although a zero return will nor- mally mean that the connection was closed. If the port name is supplied as part of the host name then this will override any value set with _B_I_O___s_e_t___c_o_n_n___p_o_r_t_(_). This may be undesir- able if the application does not wish to allow connection to arbitrary ports. This can be avoided by checking for the presence of the ':' character in the passed hostname and either indicating an error or truncating the string at that point. The values returned by _B_I_O___g_e_t___c_o_n_n___h_o_s_t_n_a_m_e_(_), _B_I_O___g_e_t___c_o_n_n___p_o_r_t_(_), _B_I_O___g_e_t___c_o_n_n___i_p_(_) and _B_I_O___g_e_t___c_o_n_n___i_n_t___p_o_r_t_(_) are updated when a con- nection attempt is made. Before any connection attempt the values returned are those set by the application itself. Applications do not have to call _B_I_O___d_o___c_o_n_n_e_c_t_(_) but may wish to do so to separate the connection process from other I/O processing. If non blocking I/O is set then retries will be requested as appropri- ate. It addition to _B_I_O___s_h_o_u_l_d___r_e_a_d_(_) and _B_I_O___s_h_o_u_l_d___w_r_i_t_e_(_) it is also pos- sible for _B_I_O___s_h_o_u_l_d___i_o___s_p_e_c_i_a_l_(_) to be true during the initial connec- tion process with the reason BIO_RR_CONNECT. If this is returned then this is an indication that a connection attempt would block, the appli- cation should then take appropriate action to wait until the underlying socket has connected and retry the call. _B_I_O___s_e_t___c_o_n_n___h_o_s_t_n_a_m_e_(_), _B_I_O___s_e_t___c_o_n_n___p_o_r_t_(_), _B_I_O___s_e_t___c_o_n_n___i_p_(_), _B_I_O___s_e_t___c_o_n_n___i_n_t___p_o_r_t_(_), _B_I_O___g_e_t___c_o_n_n___h_o_s_t_n_a_m_e_(_), _B_I_O___g_e_t___c_o_n_n___p_o_r_t_(_), _B_I_O___g_e_t___c_o_n_n___i_p_(_), _B_I_O___g_e_t___c_o_n_n___i_n_t___p_o_r_t_(_), _B_I_O___s_e_t___n_b_i_o_(_) and _B_I_O___d_o___c_o_n_n_e_c_t_(_) are macros. RREETTUURRNN VVAALLUUEESS _B_I_O___s___c_o_n_n_e_c_t_(_) returns the connect BIO method. _B_I_O___g_e_t___f_d_(_) returns the socket or -1 if the BIO has not been initial- ized. _B_I_O___s_e_t___c_o_n_n___h_o_s_t_n_a_m_e_(_), _B_I_O___s_e_t___c_o_n_n___p_o_r_t_(_), _B_I_O___s_e_t___c_o_n_n___i_p_(_) and _B_I_O___s_e_t___c_o_n_n___i_n_t___p_o_r_t_(_) always return 1. _B_I_O___g_e_t___c_o_n_n___h_o_s_t_n_a_m_e_(_) returns the connected hostname or NULL is none was set. _B_I_O___g_e_t___c_o_n_n___p_o_r_t_(_) returns a string representing the connected port or NULL if not set. _B_I_O___g_e_t___c_o_n_n___i_p_(_) returns a pointer to the connected IP address in binary form or all zeros if not set. _B_I_O___g_e_t___c_o_n_n___i_n_t___p_o_r_t_(_) returns the connected port or 0 if none was set. _B_I_O___s_e_t___n_b_i_o_(_) always returns 1. _B_I_O___d_o___c_o_n_n_e_c_t_(_) returns 1 if the connection was successfully estab- lished and 0 or -1 if the connection failed. EEXXAAMMPPLLEE This is example connects to a webserver on the local host and attempts to retrieve a page and copy the result to standard output. BIO *cbio, *out; int len; char tmpbuf[1024]; ERR_load_crypto_strings(); cbio = BIO_new_connect("localhost:http"); out = BIO_new_fp(stdout, BIO_NOCLOSE); if(BIO_do_connect(cbio) <= 0) { fprintf(stderr, "Error connecting to server\n"); ERR_print_errors_fp(stderr); /* whatever ... */ } BIO_puts(cbio, "GET / HTTP/1.0\n\n"); for(;;) { len = BIO_read(cbio, tmpbuf, 1024); if(len <= 0) break; BIO_write(out, tmpbuf, len); } BIO_free(cbio); BIO_free(out); SSEEEE AALLSSOO TBA 1.0.2u 2019-12-20 BIO_s_connect(3)