BIO_ADDRINFO(3SSL)

📦
version 4.0.3 · 13 versions
, in ubuntu stonking

💖 BIO_ADDRINFO 💖

okay bestie, welcome to the BIO_ADDRINFO page from the OpenSSL manual (section 3SSL, we're fancy like that) ✨

🌸 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 — the BIO_ADDRINFO type and all its little routines 🫶

✨ SYNOPSIS ✨

like here's the whole cast list, no cap:

#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 *host, 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 👑

So the tea is: BIO_ADDRINFO is a wrapper for the address information types your platform already ships with. it's giving "we didn't reinvent the wheel, we just put a cute little jacket on it" 💅

BIO_ADDRINFO normally forms a chain of several — and you can pick them one by one, like scrolling through a playlist until you find the one 🎀

BIO_lookup_ex() looks up a specified host and service, and uses lookup_type to figure out what the default address should be when host is NULL. then family, socktype and protocol decide what protocol family, socket type and protocol the lookup should use. fr fr:

  • family can be any of AF_INET, AF_INET6, AF_UNIX and AF_UNSPEC.
  • socktype can be SOCK_STREAM, SOCK_DGRAM or 0. setting it to 0 means any type can be used — "idc, surprise me" energy 💀
  • protocol specifies a protocol such as IPPROTO_TCP, IPPROTO_UDP or IPPORTO_SCTP. if it's set to 0 than any protocol can be used.
  • res points at a pointer that's gonna hold the start of a BIO_ADDRINFO chain 🦋

For the family AF_UNIX, BIO_lookup_ex() will ignore the service parameter and expects the host parameter to hold the path to the socket file. so like, don't bother passing a service there bestie, it's not listening 🙈

BIO_lookup() does the same as BIO_lookup_ex() but doesn't give you 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. it's the real one underneath the jacket, iconic 🌈

BIO_ADDRINFO_next() returns the next BIO_ADDRINFO in the chain from the given one. chain-walking main character energy ⭐

BIO_ADDRINFO_free() frees the chain of BIO_ADDRINFO starting with the given one. and if the argument is NULL, nothing is done — it just vibes 😌

🎀 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. so like, check the stack, it will tell you what went wrong 🫶

All the other functions described here return 0 or NULL when the information they should return isn't available.

heads up bestie: 0 / NULL here means "not available", it does NOT mean "everything is fine". don't be out here ignoring it 💀

🔥 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(). so 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. no cap.

🌈 HISTORY 🌈

the BIO_lookup_ex() function was added in OpenSSL 1.1.1. so it's not ancient, it's just well-adjusted ✨

Copyright 2016-2024 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (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>.

and that's the whole page, bestie 🎀 this was OpenSSL 4.0.3, dated 2026-09-29, and yes, BIO_ADDRINFO(3SSL) ate and left no crumbs 💅🦋💖

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