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BIO(3)		      DragonFly Library Functions Manual		BIO(3)

NAME

BIO -- I/O abstraction

SYNOPSIS

#include <openssl/bio.h>

DESCRIPTION

A BIO is an I/O abstraction, it hides many of the underlying I/O details from an application. If an application uses a BIO for its I/O, it can transparently handle SSL connections, unencrypted network connections and file I/O. There are two types of BIO, a source/sink BIO and a filter BIO. As its name implies, a source/sink BIO is a source and/or sink of data, examples include a socket BIO and a file BIO. A filter BIO takes data from one BIO and passes it through to another, or to the application. The data may be left unmodified (for example a mes- sage digest BIO) or translated (for example an encryption BIO). The effect of a filter BIO may change according to the I/O operation it is performing: for example an encryption BIO will encrypt data if it is being written to and decrypt data if it is being read from. BIOs can be joined together to form a chain (a single BIO is a chain with one component). A chain normally consist of one source/sink BIO and one or more filter BIOs. Data read from or written to the first BIO then traverses the chain to the end (normally a source/sink BIO).

SEE ALSO

BIO_ctrl(3), BIO_f_base64(3), BIO_f_buffer(3), BIO_f_cipher(3), BIO_f_md(3), BIO_f_null(3), BIO_f_ssl(3), BIO_find_type(3), BIO_new(3), BIO_new_bio_pair(3), BIO_push(3), BIO_read(3), BIO_s_accept(3), BIO_s_bio(3), BIO_s_connect(3), BIO_s_fd(3), BIO_s_file(3), BIO_s_mem(3), BIO_s_null(3), BIO_s_socket(3), BIO_set_callback(3), BIO_should_retry(3) DragonFly 4.7 July 17, 2014 DragonFly 4.7 BIO_ADDRINFO(3) OpenSSL BIO_ADDRINFO(3)

NAME

BIO_lookup_type, BIO_ADDRINFO, BIO_ADDRINFO_next, BIO_ADDRINFO_free, BIO_ADDRINFO_family, BIO_ADDRINFO_socktype, BIO_ADDRINFO_protocol, BIO_ADDRINFO_address, BIO_lookup_ex, BIO_lookup - BIO_ADDRINFO type and routines

SYNOPSIS

#include <sys/types.h> #include <openssl/bio.h> typedef union bio_addrinfo_st BIO_ADDRINFO; enum BIO_lookup_type { BIO_LOOKUP_CLIENT, BIO_LOOKUP_SERVER }; int BIO_lookup_ex(const char *host, const char *service, int lookup_type, int family, int socktype, int protocol, BIO_ADDRINFO **res); int BIO_lookup(const char *node, const char *service, enum BIO_lookup_type lookup_type, int family, int socktype, BIO_ADDRINFO **res); const BIO_ADDRINFO *BIO_ADDRINFO_next(const BIO_ADDRINFO *bai); int BIO_ADDRINFO_family(const BIO_ADDRINFO *bai); int BIO_ADDRINFO_socktype(const BIO_ADDRINFO *bai); int BIO_ADDRINFO_protocol(const BIO_ADDRINFO *bai); const BIO_ADDR *BIO_ADDRINFO_address(const BIO_ADDRINFO *bai); void BIO_ADDRINFO_free(BIO_ADDRINFO *bai);

DESCRIPTION

The BIO_ADDRINFO type is a wrapper for address information types provided on your platform. BIO_ADDRINFO normally forms a chain of several that can be picked at one by one. BIO_lookup_ex() looks up a specified host and service, and uses lookup_type to determine what the default address should be if host is NULL. family, socktype and protocol are used to determine what protocol family, socket type and protocol should be used for the lookup. family can be any of AF_INET, AF_INET6, AF_UNIX and AF_UNSPEC. socktype can be SOCK_STREAM, SOCK_DGRAM or 0. Specifying 0 indicates that any type can be used. protocol specifies a protocol such as IPPROTO_TCP, IPPROTO_UDP or IPPORTO_SCTP. If set to 0 than any protocol can be used. res points at a pointer to hold the start of a BIO_ADDRINFO chain. For the family AF_UNIX, BIO_lookup_ex() will ignore the service parameter and expects the node parameter to hold the path to the socket file. BIO_lookup() does the same as BIO_lookup_ex() but does not provide the ability to select based on the protocol (any protocol may be returned). BIO_ADDRINFO_family() returns the family of the given BIO_ADDRINFO. The result will be one of the constants AF_INET, AF_INET6 and AF_UNIX. BIO_ADDRINFO_socktype() returns the socket type of the given BIO_ADDRINFO. The result will be one of the constants SOCK_STREAM and SOCK_DGRAM. BIO_ADDRINFO_protocol() returns the protocol id of the given BIO_ADDRINFO. The result will be one of the constants IPPROTO_TCP and IPPROTO_UDP. BIO_ADDRINFO_address() returns the underlying BIO_ADDR of the given BIO_ADDRINFO. BIO_ADDRINFO_next() returns the next BIO_ADDRINFO in the chain from the given one. BIO_ADDRINFO_free() frees the chain of BIO_ADDRINFO starting with the given one.

RETURN VALUES

BIO_lookup_ex() and BIO_lookup() return 1 on success and 0 when an error occurred, and will leave an error indication on the OpenSSL error stack in that case. All other functions described here return 0 or NULL when the information they should return isn't available.

NOTES

The BIO_lookup_ex() implementation uses the platform provided getaddrinfo() function. On Linux it is known that specifying 0 for the protocol will not return any SCTP based addresses when calling getaddrinfo(). Therefore, if an SCTP address is required then the protocol parameter to BIO_lookup_ex() should be explicitly set to IPPROTO_SCTP. The same may be true on other platforms.

HISTORY

The BIO_lookup_ex() function was added in OpenSSL 1.1.1.

COPYRIGHT

Copyright 2016-2020 The OpenSSL Project Authors. All Rights Reserved. Licensed under the OpenSSL license (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <https://www.openssl.org/source/license.html>. 1.1.1v 2023-08-01 BIO_ADDRINFO(3)

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