STRUCT IEEE80211_FAST_TX(9)

💖 NAME 💖

okay bestie, welcome to struct ieee80211_fast_tx(9) from the Kernel API Manual — we're in kernel TX fastpath territory, and this struct is main character energy. literally:

struct ieee80211_fast_tx - TX fastpath information. periodt. 💅

✨ SYNOPSIS ✨

here's the struct, no cap:

struct ieee80211_fast_tx {
    struct ieee80211_key *key;
    u8 hdr_len;
    u8 sa_offs, da_offs, pn_offs;
    u8 band;
    u8 hdr[30 + 2 + IEEE80211_FAST_XMIT_MAX_IV +
sizeof(rfc1042_header)];
    struct rcu_head rcu_head;
 };

🎀 Members 🎀

• key — key to use for hw crypto 🔑
• hdr_len — actual 802.11 header length
• sa_offs — offset of the SA
• da_offs — offset of the DA
• pn_offs — offset where to put PN for crypto (or 0 if not needed)
• band — band this will be transmitted on, for tx_info
• hdr — the 802.11 header to put with the frame
• rcu_head — RCU head to free this struct

💅 Description 💅

so the whole vibe: this struct is small enough so that the common case (maximum crypto header length of 8 like for CCMP/GCMP) fits into a single 64-byte cache line. iconic. ✨

🔥 SEE ALSO 🔥

go read these too, bestie — same kernel friend group:

• Kernel file ./net/mac80211/sta_info.h
• enum ieee80211_sta_info_flags(9)
• struct tid_ampdu_tx(9)
• struct tid_ampdu_rx(9)
• struct sta_ampdu_mlme(9)
• struct ieee80211_fast_rx(9)
• struct mesh_sta(9)
• struct link_sta_info(9)
• struct ieee80211_sta_removed_link_stats(9)
• struct sta_info(9)
• __sta_info_flush(9)
• sta_info_flush(9)

sign-off: source/version is ./net/mac80211, date is October 2026, and the page is struct ieee80211_fast_tx(9). mwah 💋🌸