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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_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 hostname name.
\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 \*(C`[\*(C' and \*(C`]\*(C'. The hostname can also include the port in the form hostname:port; see BIO_parse_hostserv\|(3) and BIO_set_conn_port() for details.
\fBBIO_set_conn_port() sets the port to port. port can be the numerical form or a service string such as \*(L"http\*(R", which will be mapped to a port number using the system function getservbyname().
\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_do_connect() attempts to connect the supplied \s-1BIO.\s0 This performs an \s-1SSL/TLS\s0 handshake as far as supported by the \s-1BIO.\s0 For non-SSL BIOs the connection is done typically at \s-1TCP\s0 level. If domain name resolution yields multiple \s-1IP\s0 addresses all of them are tried after connect() failures. The function 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 a connection has already been established this call has no effect.
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_set_conn_address(), BIO_set_conn_port(), and BIO_set_conn_ip_family() return 1 or <=0 if an error occurs.
\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() returns 1 or <=0 if an error occurs.
\fBBIO_do_connect() returns 1 if the connection was successfully established and <=0 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 Apache License 2.0 (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>.