scan_ip6if(3)

💖 scan_ip6if(3) — like, the manual page, but make it make sense 💖

okay bestie, welcome to the scan_ip6if(3) page from the Library Functions Manual 🌸 this is the one that takes an IPv6 number and an interface off a string and hands you back the goods. sit down, hydrate, let's go 🫶

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✨ NAME ✨

scan_ip6 — parse an IPv6 number and interface in ASCII representation

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✨ SYNTAX ✨

no cap, this is literally the whole thing you gotta write:

#include <libowfat/ip6.h>

int scan_ip6if(const char *src,char ip[16],uint32* scope_id);

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✨ DESCRIPTION ✨

so scan_ip6if reads an IPv6 number from src — in RFC1884 ASCII representation, periodt — and writes the result into ip. that's the main character job 💅

but wait, there's more. if that IPv6 number is followed by a percent sign, scan_ip6if grabs the word that comes right after it, tries to parse that as a network interface, and writes the result to scope_id. cute, right? 🎀

it returns the number of bytes read from src, or 0 if the parsing failed. zero means it didn't eat, and not in the good way 😭

here's the range it has: scan_ip6if accepts upper and lower case hex letters, it understands "::" compression, and it gets partial IPv4 addresses like in "::FFFF:129.144.52.38". iconic behaviour fr fr ✨

and because we want IPv4 to slide into IPv6 applications transparently, scan_ip6if also understands IPv4 addresses in dotted-decimal notation and will return an IPv4-mapped IPv6 address. so like, "127.0.0.1" will be parsed as "::FFFF:127.0.0.1". 🦋

lowkey important: unlike many other IP parsing routines, scan_ip6if does not recognize octal (like 0177.0.0.1) or hexadecimal numbers (like 0x7f000001) in the IPv4 part. it's not doing all that. 💀

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✨ EXAMPLE ✨

here's the vibe check, verbatim:

#include <libowfat/str.h>
#include <libowfat/ip6.h>

  char buf[]="::1%lo";
  char ip[16];
  uint32 scope_id;
  if (scan_ip6if(buf,ip,&scope_id) != str_len(buf))
    parse_error();

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✨ SEE ALSO ✨

go read these next, bestie, they're all in the friend group 👑:

• fmt_ip6(3)
• scan_ip4(3)
• fmt_ip6if(3)

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and that's the whole page, no notes 💜 this was scan_ip6if(3) from the Library Functions Manual — section 3, the library functions section, the one we live in. mwah. go parse something. 🌈✨