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      1 =pod
      2 
      3 =head1 NAME
      4 
      5 BIO_lookup_type,
      6 BIO_ADDRINFO, BIO_ADDRINFO_next, BIO_ADDRINFO_free,
      7 BIO_ADDRINFO_family, BIO_ADDRINFO_socktype, BIO_ADDRINFO_protocol,
      8 BIO_ADDRINFO_address,
      9 BIO_lookup_ex,
     10 BIO_lookup
     11 - BIO_ADDRINFO type and routines
     12 
     13 =head1 SYNOPSIS
     14 
     15  #include <sys/types.h>
     16  #include <openssl/bio.h>
     17 
     18  typedef union bio_addrinfo_st BIO_ADDRINFO;
     19 
     20  enum BIO_lookup_type {
     21      BIO_LOOKUP_CLIENT, BIO_LOOKUP_SERVER
     22  };
     23 
     24  int BIO_lookup_ex(const char *host, const char *service, int lookup_type,
     25                    int family, int socktype, int protocol, BIO_ADDRINFO **res);
     26  int BIO_lookup(const char *host, const char *service,
     27                 enum BIO_lookup_type lookup_type,
     28                 int family, int socktype, BIO_ADDRINFO **res);
     29 
     30  const BIO_ADDRINFO *BIO_ADDRINFO_next(const BIO_ADDRINFO *bai);
     31  int BIO_ADDRINFO_family(const BIO_ADDRINFO *bai);
     32  int BIO_ADDRINFO_socktype(const BIO_ADDRINFO *bai);
     33  int BIO_ADDRINFO_protocol(const BIO_ADDRINFO *bai);
     34  const BIO_ADDR *BIO_ADDRINFO_address(const BIO_ADDRINFO *bai);
     35  void BIO_ADDRINFO_free(BIO_ADDRINFO *bai);
     36 
     37 =head1 DESCRIPTION
     38 
     39 The B<BIO_ADDRINFO> type is a wrapper for address information
     40 types provided on your platform.
     41 
     42 B<BIO_ADDRINFO> normally forms a chain of several that can be
     43 picked at one by one.
     44 
     45 BIO_lookup_ex() looks up a specified B<host> and B<service>, and
     46 uses B<lookup_type> to determine what the default address should
     47 be if B<host> is B<NULL>. B<family>, B<socktype> and B<protocol> are used to
     48 determine what protocol family, socket type and protocol should be used for
     49 the lookup.  B<family> can be any of AF_INET, AF_INET6, AF_UNIX and
     50 AF_UNSPEC. B<socktype> can be SOCK_STREAM, SOCK_DGRAM or 0. Specifying 0
     51 indicates that any type can be used. B<protocol> specifies a protocol such as
     52 IPPROTO_TCP, IPPROTO_UDP or IPPORTO_SCTP. If set to 0 than any protocol can be
     53 used. B<res> points at a pointer to hold the start of a B<BIO_ADDRINFO>
     54 chain.
     55 
     56 For the family B<AF_UNIX>, BIO_lookup_ex() will ignore the B<service>
     57 parameter and expects the B<host> parameter to hold the path to the socket file.
     58 
     59 BIO_lookup() does the same as BIO_lookup_ex() but does not provide the ability
     60 to select based on the protocol (any protocol may be returned).
     61 
     62 BIO_ADDRINFO_family() returns the family of the given
     63 B<BIO_ADDRINFO>.  The result will be one of the constants
     64 AF_INET, AF_INET6 and AF_UNIX.
     65 
     66 BIO_ADDRINFO_socktype() returns the socket type of the given
     67 B<BIO_ADDRINFO>.  The result will be one of the constants
     68 SOCK_STREAM and SOCK_DGRAM.
     69 
     70 BIO_ADDRINFO_protocol() returns the protocol id of the given
     71 B<BIO_ADDRINFO>.  The result will be one of the constants
     72 IPPROTO_TCP and IPPROTO_UDP.
     73 
     74 BIO_ADDRINFO_address() returns the underlying B<BIO_ADDR>
     75 of the given B<BIO_ADDRINFO>.
     76 
     77 BIO_ADDRINFO_next() returns the next B<BIO_ADDRINFO> in the chain
     78 from the given one.
     79 
     80 BIO_ADDRINFO_free() frees the chain of B<BIO_ADDRINFO> starting
     81 with the given one. If the argument is NULL, nothing is done.
     82 
     83 =head1 RETURN VALUES
     84 
     85 BIO_lookup_ex() and BIO_lookup() return 1 on success and 0 when an error
     86 occurred, and will leave an error indication on the OpenSSL error stack in that
     87 case.
     88 
     89 All other functions described here return 0 or B<NULL> when the
     90 information they should return isn't available.
     91 
     92 =head1 NOTES
     93 
     94 The BIO_lookup_ex() implementation uses the platform provided getaddrinfo()
     95 function. On Linux it is known that specifying 0 for the protocol will not
     96 return any SCTP based addresses when calling getaddrinfo(). Therefore, if an SCTP
     97 address is required then the B<protocol> parameter to BIO_lookup_ex() should be
     98 explicitly set to IPPROTO_SCTP. The same may be true on other platforms.
     99 
    100 =head1 HISTORY
    101 
    102 The BIO_lookup_ex() function was added in OpenSSL 1.1.1.
    103 
    104 =head1 COPYRIGHT
    105 
    106 Copyright 2016-2024 The OpenSSL Project Authors. All Rights Reserved.
    107 
    108 Licensed under the Apache License 2.0 (the "License").  You may not use
    109 this file except in compliance with the License.  You can obtain a copy
    110 in the file LICENSE in the source distribution or at
    111 L<https://www.openssl.org/source/license.html>.
    112 
    113 =cut
    114