STRUCT SOCKADDR_UNSIZED(9)

💅 struct sockaddr_unsized(9) 💅

okay so bestie, welcome to the Kernel API Manual — today's main character is struct sockaddr_unsized, and she is literally the flexible friend your callbacks have been waiting for 🦋

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✨ NAME ✨

struct sockaddr_unsized — an unspecified-size sockaddr made for callbacks 🎀

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🌸 SYNOPSIS 🌸

struct sockaddr_unsized {
    __kernel_sa_family_t sa_family;
    char sa_data[];
 };

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💖 Members 💖

• sa_family — the address family, iykyk. Think AF_UNIX, AF_INET, AF_INET6, etc. 👑
• sa_data — the flexible array holding the actual address data. she stretches, she adapts, she's iconic ✨

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🧚 Description 🧚

so here's the vibe: this structure was designed for callback interfaces where the total size is already known via the sockaddr_len parameter. no guessing, no drama, the size comes from outside 💅

and like, let's talk about her sisters for a sec:

• struct sockaddr has a fixed 14-byte sa_data limit 🙈
• struct sockaddr_storage has a fixed 128-byte sa_data limit 🫶

not this one tho. struct sockaddr_unsized can accommodate addresses of any size — so she can do it all, no cap. 🔥

but bestie, hear me: she must be used carefully. this is not a "vibe and see what happens" situation, fr fr. the size lives in sockaddr_len, so you'd better be keeping track of it. 😭

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🌈 SEE ALSO 🌈

• Kernel file ./tools/perf/trace/beauty/include/linux/socket.h — go read it, it's giving source of truth 📖💜

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anyway that's the page, bestie!! keep those sizes tracked and those callbacks slaying 💅✨

sign-off time: this lil masterpiece comes from ./tools/perf/trace/beauty/incl... and is dated October 2026 — so like, future iconic behavior fr 🎀🌟