STRUCT GSM_CONFIG(9)

💖 NAME 💖

struct gsm_config — the basic configuration parameters for n_gsm, bestie. that's it, that's the whole vibe ✨

so you know how this page is from the Kernel API Manual? yeah. we're in kernel land now and we're gonna have fun with it 🎀

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🌸 SYNOPSIS 🌸

struct gsm_config {
    unsigned int adaption;
    unsigned int encapsulation;
    unsigned int initiator;
    unsigned int t1;
    unsigned int t2;
    unsigned int t3;
    unsigned int n2;
    unsigned int mru;
    unsigned int mtu;
    unsigned int k;
    unsigned int i;
    unsigned int unused[8];
 };

like… look at her. twelve fields. eight of them are just vibes (unused, we'll get to you). iconic honestly 👑

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🦋 Members 🦋

okay so let's go field by field, no skipping, we don't do that here 💅

• adaption — the convergence layer type, periodt.
• encapsulation — the framing. it's 0 = basic option, 1 = advanced option. pick your fighter 🥊
• initiator — initiator or responder. are you the one starting things or the one responding? main character or supporting cast, no wrong answer 💫
• t1 — Acknowledgment timer ⏰
• t2 — Response timer for the multiplexer control channel ⏰
• t3 — Response timer for the wake-up procedure ⏰ (yes girl, wake up 🌞)
• n2 — Maximum number of retransmissions 🔁
• mru — Maximum incoming frame payload size 📥
• mtu — Maximum outgoing frame payload size 📤
• k — Window size 🪟
• i — Frame type, and it's 1 = UIH, 2 = UI. just those two, don't get creative 😌
• unused — Can not be used. that's it. that's the description. hands off the unused array bestie 🙈 (it's literally eight unsigned ints of do not touch)

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✨ Description ✨

so this structure is used in combination with GSMIOC_GETCONF and GSMIOC_SETCONF to retrieve and set the basic parameters of an n_gsm ldisc. like, that's the whole job 🫶

and if you want to configure the extended ldisc parameters? that's not this girl. that's struct gsm_config_ext, she has her own page 💁‍♀️

🚨 important lore: all timers are in units of 1/100th of a second. so like, do the math. t1 of 100 = one second. ngl this is the detail everyone forgets and it's giving chaos 😭

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🌈 SEE ALSO 🌈

• Kernel file ./include/uapi/linux/gsmmux.h — also: struct gsm_netconfig(9), struct gsm_config_ext(9), struct gsm_dlci_config(9) 🦋 go read those too, i'll wait

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and that's the page!! 💜 source lives at ./include/uapi/linux, dated October 2026, and it's struct gsm_config(9) in the Kernel API Manual — slay, go configure ur ldisc, mwah 🎀💋