HelenOS sources

TK_OFFSET         634 uspace/lib/ieee80211/src/ieee80211.c 		    TK_OFFSET + IEEE80211_TKIP_TX_MIC_OFFSET;
TK_OFFSET        1587 uspace/lib/ieee80211/src/ieee80211.c 		    ptk + TK_OFFSET, ptk_key_length - TK_OFFSET);
HelenOS homepage, sources at GitHub