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.tr \(*W- . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' . ds C` . ds C' 'br\}
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Title "BIO_s_connect 3"
way too many mistakes in technical documents.
Using connect BIOs, \s-1TCP/IP\s0 connections can be made and data transferred using only \s-1BIO\s0 routines. In this way any platform specific operations are hidden by the \s-1BIO\s0 abstraction.
Read and write operations on a connect \s-1BIO\s0 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 \s-1BIO\s0 then any active connection is shutdown and the socket closed when the \s-1BIO\s0 is freed.
Calling BIO_reset() on a connect \s-1BIO\s0 will close any active connection and reset the \s-1BIO\s0 into a state where it can connect to the same host again.
\fIBIO_get_fd() places the underlying socket in c if it is not \s-1NULL,\s0 it also returns the socket . If c is not \s-1NULL\s0 it should be of type (int *).
\fIBIO_set_conn_hostname() uses the string name to set the hostname. The hostname can be an \s-1IP\s0 address. The hostname can also include the port in the form hostname:port . It is also acceptable to use the form \*(L"hostname/any/other/path\*(R" or \*(L"hostname:port/any/other/path\*(R".
\fIBIO_set_conn_port() sets the port to port. port can be the numerical form or a string such as \*(L"http\*(R". 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.
\fIBIO_set_conn_ip() sets the \s-1IP\s0 address to ip using binary form, that is four bytes specifying the \s-1IP\s0 address in big-endian form.
\fIBIO_set_conn_int_port() sets the port using port. port should be of type (int *).
\fIBIO_get_conn_hostname() returns the hostname of the connect \s-1BIO\s0 or \s-1NULL\s0 if the \s-1BIO\s0 is initialized but no hostname is set. This return value is an internal pointer which should not be modified.
\fIBIO_get_conn_port() returns the port as a string.
\fIBIO_get_conn_ip() returns the \s-1IP\s0 address in binary form.
\fIBIO_get_conn_int_port() returns the port as an int.
\fIBIO_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.
\fIBIO_new_connect() combines BIO_new() and BIO_set_conn_hostname() into a single call: that is it creates a new connect \s-1BIO\s0 with name.
\fIBIO_do_connect() attempts to connect the supplied \s-1BIO.\s0 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.
If the port name is supplied as part of the host name then this will override any value set with BIO_set_conn_port(). This may be undesirable 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 BIO_get_conn_hostname(), BIO_get_conn_port(), \fIBIO_get_conn_ip() and BIO_get_conn_int_port() are updated when a connection attempt is made. Before any connection attempt the values returned are those set by the application itself.
Applications do not have to call BIO_do_connect() 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 appropriate.
It addition to BIO_should_read() and BIO_should_write() it is also possible for BIO_should_io_special() to be true during the initial connection process with the reason \s-1BIO_RR_CONNECT.\s0 If this is returned then this is an indication that a connection attempt would block, the application should then take appropriate action to wait until the underlying socket has connected and retry the call.
\fIBIO_set_conn_hostname(), BIO_set_conn_port(), BIO_set_conn_ip(), \fIBIO_set_conn_int_port(), BIO_get_conn_hostname(), BIO_get_conn_port(), \fIBIO_get_conn_ip(), BIO_get_conn_int_port(), BIO_set_nbio() and \fIBIO_do_connect() are macros.
\fIBIO_get_fd() returns the socket or -1 if the \s-1BIO\s0 has not been initialized.
\fIBIO_set_conn_hostname(), BIO_set_conn_port(), BIO_set_conn_ip() and \fIBIO_set_conn_int_port() always return 1.
\fIBIO_get_conn_hostname() returns the connected hostname or \s-1NULL\s0 is none was set.
\fIBIO_get_conn_port() returns a string representing the connected port or \s-1NULL\s0 if not set.
\fIBIO_get_conn_ip() returns a pointer to the connected \s-1IP\s0 address in binary form or all zeros if not set.
\fIBIO_get_conn_int_port() returns the connected port or 0 if none was set.
\fIBIO_set_nbio() always returns 1.
\fIBIO_do_connect() returns 1 if the connection was successfully established and 0 or -1 if the connection failed.
.Vb 10 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\en"); ERR_print_errors_fp(stderr); /* whatever ... */ } BIO_puts(cbio, "GET / HTTP/1.0\en\en"); for(;;) { len = BIO_read(cbio, tmpbuf, 1024); if(len <= 0) break; BIO_write(out, tmpbuf, len); } BIO_free(cbio); BIO_free(out); .Ve