IPV6_RECVPKTINFO(2const)

💖 IPV6_RECVPKTINFO 💖

okay bestie, so you're reading the IPV6_RECVPKTINFO page from the man-pages section 2const, and honestly? it's a short one, but it's so useful, trust. it lives in the Standard C library (libc, -lc) and it's all about making your incoming datagrams spill the tea about where they came from. let's get into it 🫶

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✨ NAME ✨

IPV6_RECVPKTINFO — set delivery of the IPV6_PKTINFO control message on incoming datagrams

like. the name literally ate. it tells the kernel "hey bestie, when datagrams roll up to my socket, pls also send me the IPV6_PKTINFO control message." 🌸

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🌈 LIBRARY 🌈

Standard C library (libc, -lc)

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🦋 SYNOPSIS 🦋

#include <netinet/in.h>  /* Definition of IP* constants */
#include <sys/socket.h>

int setsockopt(int sockfd, IPPROTO_IPV6, IPV6_RECVPKTINFO,
               const int *enable, sizeof(int));

no cap, that's the whole vibe. you're calling setsockopt() with IPPROTO_IPV6 as the level and IPV6_RECVPKTINFO as the option name, and you hand it a pointer to an int named enable plus sizeof(int). 💅

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👑 DESCRIPTION 👑

Set delivery of the IPV6_PKTINFO control message on incoming datagrams. 🎀

Such control messages contain a struct in6_pktinfo, as per RFC 3542.

Allowed only for SOCK_DGRAM or SOCK_RAW sockets.

okay so let me translate that into group-chat: you flip this option on, and every incoming datagram gets a lil bonus control message riding along with it. that message is a struct in6_pktinfo — RFC 3542 said so, periodt. ✨

vibe check: this is only allowed on SOCK_DGRAM or SOCK_RAW sockets. other socket types? not invited to the party 🙈

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💀 ERRORS 💀

See IPPROTO_IPV6(2const). See setsockopt(2). See ipv6(7).

that's it, that's the section. the error lore lives in those pages, so go read them if something's acting up bestie 😭

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⭐ HISTORY ⭐

Linux 2.6.14.

an icon from way back, we love a legacy queen 👑

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🌸 SEE ALSO 🌸

• IPPROTO_IPV6(2const)
• setsockopt(2)
• cmsg(3)
• ipv6(7)

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that's the whole page, no filler, all facts, we ate and left no crumbs 🍓

mwah 💋 — this was IPV6_RECVPKTINFO from Linux man-pages 6.20, dated 2025-12-02. go set some socket options, main character 💜