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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.
\fBBIO_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 *).
\fBBIO_set_conn_hostname() uses the string name to set the hostname. The hostname can be an \s-1IP\s0 address; if the address is an IPv6 one, it must be enclosed with brackets. The hostname can also include the port in the form hostname:port.
\fBBIO_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. This internal list is http, telnet, socks, https, ssl, ftp, and gopher.
\fBBIO_set_conn_address() sets the address and port information using a \s-1BIO_ADDR\s0\|(3ssl).
\fBBIO_set_conn_ip_family() sets the \s-1IP\s0 family.
\fBBIO_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.
\fBBIO_get_conn_port() returns the port as a string. This return value is an internal pointer which should not be modified.
\fBBIO_get_conn_address() returns the address information as a \s-1BIO_ADDR.\s0 This return value is an internal pointer which should not be modified.
\fBBIO_get_conn_ip_family() returns the \s-1IP\s0 family of the connect \s-1BIO.\s0
\fBBIO_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.
\fBBIO_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.
\fBBIO_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 hostname 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_address(), and BIO_get_conn_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.
\fBBIO_set_conn_hostname(), BIO_set_conn_port(), BIO_get_conn_hostname(), \fBBIO_set_conn_address(), BIO_get_conn_port(), BIO_get_conn_address(), \fBBIO_set_conn_ip_family(), BIO_get_conn_ip_family(), \fBBIO_set_nbio(), and BIO_do_connect() are macros.
\fBBIO_get_fd() returns the socket or -1 if the \s-1BIO\s0 has not been initialized.
\fBBIO_set_conn_address(), BIO_set_conn_port(), and BIO_set_conn_ip_family() always return 1.
\fBBIO_set_conn_hostname() returns 1 on success and 0 on failure.
\fBBIO_get_conn_address() returns the address information or \s-1NULL\s0 if none was set.
\fBBIO_get_conn_hostname() returns the connected hostname or \s-1NULL\s0 if none was set.
\fBBIO_get_conn_ip_family() returns the address family or -1 if none was set.
\fBBIO_get_conn_port() returns a string representing the connected port or \s-1NULL\s0 if not set.
\fBBIO_set_nbio() always returns 1.
\fBBIO_do_connect() returns 1 if the connection was successfully established and 0 or -1 if the connection failed.
.Vb 3 BIO *cbio, *out; int len; char tmpbuf[1024]; \& 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); exit(1); } 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
Licensed under the OpenSSL license (the \*(L"License\*(R"). You may not use this file except in compliance with the License. You can obtain a copy in the file \s-1LICENSE\s0 in the source distribution or at <https://www.openssl.org/source/license.html>.