KCAPI_KPP_SSGEN_AIO(3)

📦
version 1.5.0 · 7 versions
, in fedora 43

✨ KCAPI_KPP_SSGEN_AIO ✨

okay bestie, gather round 🫶 this is a section 3 page from the libkcapi manual (the "Programming Interface" corner of the world), and it's about kcapi_kpp_ssgen_aio — generating a shared secret, asynchronous one shot style. one shot. no second chances. main character energy only 💅

🌸 NAME 🌸

kcapi_kpp_ssgen_aio — generate a shared secret (asynchronous one shot) 🔐✨

🎀 SYNOPSIS 🎀

ssize_t kcapi_kpp_ssgen_aio(struct kcapi_handle * handle,
                            struct iovec * iniov, struct iovec * outiov,
                            size_t iovlen, int access);

like. that's the whole function signature. she's compact, she's powerful, she's literally iconic 💖

🦋 ARGUMENTS 🦋

  • handle — [in] cipher handle. your little handle bestie, the one you already got from somewhere 💫
  • iniov — [in] head of scatter-gather list of the source buffers with the public keys of the peer. yes, the peer. the other party. the person on the other end of the secret 🤝
  • outiov — [out] head of scatter-gather list of the destination buffers filled with the generated shared secret. this is where the magic gets deposited ✨🔮
  • iovlen — [in] number of scatter-gather list entries. count 'em, bestie 🔢
  • access — [in] kernel access type. and the options are:
    • KCAPI_ACCESS_HEURISTIC — use internal heuristic for fastest kernel access 🏎️
    • KCAPI_ACCESS_VMSPLICE — use vmsplice access 🧵
    • KCAPI_ACCESS_SENDMSG — sendmsg access 📨

💖 DESCRIPTION 💖

so the individual scatter-gather list entries? each one gets processed with separate invocations of the the given cipher. not one big blob — separate. invocations. periodt 💅

ngl, there's a memory thing you cannot skip: the memory should be aligned at the page boundary using

posix_memalign(sysconf(_SC_PAGESIZE))

and if it is not aligned at the page boundary, the vmsplice call may not send all data to the kernel 😭 so like… align it. please. for me. for us. 🥺

fr fr, misaligned memory + vmsplice = data that never made it to the kernel. that's not a vibe, that's a bug. do the posix_memalign thing 🙈

and the return? it returns the number of bytes verify upon success; a negative errno-style error code if an error occurred. so like, positive number = slay, negative number = something went wrong, go read your errno 💀

👑 AUTHOR 👑

Stephan Mueller <smueller@chronox.de> — Author. the legend themselves, we stan 🫶⭐

copyright vibes live in the footer, bestie, so here we go — this page is from the libkcapi Manual 1.5.0, dated July 2025 🌈💫

that's the whole thing. go align your memory and generate that shared secret, you absolute icon 🧚🎀💅

📦 where this page comes from