cnstr_shdsc_gcm_decap(9)

💅 cnstr_shdsc_gcm_decap — gcm decapsulation shared descriptor 🎀

okay so bestie, welcome to the cnstr_shdsc_gcm_decap(9) page from the Kernel API Manual. yes she's niche. yes she's iconic. let's get into it ✨

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🌸 NAME 🌸

cnstr_shdsc_gcm_decap — literally the gcm decapsulation shared descriptor builder. that's her job, that's her whole vibe 💅

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🦋 SYNOPSIS 🦋

void cnstr_shdsc_gcm_decap (u32 * const desc , struct alginfo *cdata ,
unsigned int ivsize , unsigned int icvsize , const bool is_qi );

returns void, so no spoilers, no return value, she just does the thing 🙈

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🔥 ARGUMENTS 🔥

• desc — pointer to the buffer that gets used for descriptor construction. she's the canvas, the main character 🎨
• cdata — pointer to block cipher transform definitions. valid algorithm values are OP_ALG_ALGSEL_AES ANDed with OP_ALG_AAI_GCM. and yes bestie, that's ANDed, with a capital AND-ed, don't @ me 👑
• ivsize — initialization vector size, the size of the iv, that's the whole vibe ⭐
• icvsize — integrity check value (ICV) size. and it can be truncated or full, so either way she ate 🍓
• is_qi — true when called from caam/qi. like, that's the whole check. true = came from caam/qi, and that's the tea ☕

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🌈 SEE ALSO 🌈

the kernel file that lives with all this:

./drivers/crypto/caam/caamalg_desc.c

and the whole friend group, fr fr — these are her people, go say hi 🫶

cnstr_shdsc_aead_null_encap(9), cnstr_shdsc_aead_null_decap(9), cnstr_shdsc_aead_encap(9), cnstr_shdsc_aead_decap(9), cnstr_shdsc_aead_givencap(9), cnstr_shdsc_gcm_encap(9), cnstr_shdsc_rfc4106_encap(9), cnstr_shdsc_rfc4106_decap(9), cnstr_shdsc_rfc4543_encap(9), cnstr_shdsc_rfc4543_decap(9), cnstr_shdsc_chachapoly(9), cnstr_shdsc_skcipher_encap(9), cnstr_shdsc_skcipher_decap(9), cnstr_shdsc_xts_skcipher_encap(9), cnstr_shdsc_xts_skcipher_decap(9)

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lowkey obsessed with how many of these there are. encap, decap, null, givencap — the caam family is huge and every single one of them got a manpage. periodt 💀

and that's a wrap, bestie 🎀 this page comes to you from ./drivers/crypto/caam, dated October 2026, filed under cnstr_shdsc_gcm_decap(9) — catch you in the next one, mwah 💖