dns_ip6_qualify(3)

💖 dns_ip6_qualify — from the Library Functions Manual, bestie 💖

okay so picture this: you're in <libowfat/dns.h, it's giving resolver era, and you need a name qualified AND its IPv6 addresses looked up. that's literally this function's whole job. slay. 💅

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✨ NAME ✨

dns_ip6_qualify — qualify a name and look up IPv6 addresses 🦋

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🌸 SYNTAX 🌸

#include <libowfat/dns.h>

int dns_ip6_qualify(stralloc* out,stralloc* fqdn,
                    const stralloc* udn);

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💫 DESCRIPTION 💫

so here's the vibe: dns_ip6_qualify takes the name udn, feeds it through qualification, and then looks up 16-byte IPv6 addresses for whatever comes out the other side. no cap. 🔥

here's what it does with all of that:

• it puts the fully qualified domain name into fqdn
• it puts the concatenation of the IP addresses into out
• it returns 0

and if the domain doesn't exist in DNS, or it just has no IP addresses at all? out will be empty. it's giving ghosted. 😭

ngl the cute part is this: dns_ip6_qualify also looks up 4-byte IPv4 addresses and converts them into IPv4-mapped IPv6 addresses (::ffff:1.2.3.4) so that IPv6 apps get easy backwards compatibility. iconic behaviour, honestly. 👑

but bestie, listen — if dns_ip6_qualify has trouble with the qualification, or has trouble with DNS, or just runs out of memory, it returns -1 and sets errno appropriately. and here's the spicy bit: it may or may not change out and fqdn. so don't be out here assuming they're untouched, fr fr. 💀

⚠️ heads up: -1 means something went wrong, and out / fqdn are in a maybe state. check errno, don't trust the buffers blindly. 🙈

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🎀 QUALIFICATION 🎀

for the full qualification lore, go read:

http://cr.yp.to/djbdns/qualification.html

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🌈 SEE ALSO 🌈

• dns_ip6(3)
• dns_ip6_packet(3)
• dns_ip4_qualify(3)

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and that's the whole page, bestie 🫶 straight from the Library Functions Manual, filed under dns_ip6_qualify(3) — no date on this one, she's timeless like that. go qualify something. 💜✨