1.\" 2.\" Copyright (c) 2004 Bruce M. Simpson <bms@spc.org> 3.\" Copyright (c) 2004 Darron Broad <darron@kewl.org> 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25.\" SUCH DAMAGE. 26.\" 27.Dd August 4, 2009 28.Dt IEEE80211_INPUT 9 29.Os 30.Sh NAME 31.Nm ieee80211_input 32.Nd software 802.11 stack input functions 33.Sh SYNOPSIS 34.In net80211/ieee80211_var.h 35.Ft void 36.Fo ieee80211_input 37.Fa "struct ieee80211_node *" 38.Fa "struct mbuf *" 39.Fa "int rssi" 40.Fa "int noise" 41.Fc 42.Ft void 43.Fo ieee80211_input_all 44.Fa "struct ieee80211com *" 45.Fa "struct mbuf *" 46.Fa "int rssi" 47.Fa "int noise" 48.Fc 49.Sh DESCRIPTION 50The 51.Nm net80211 52layer that supports 802.11 device drivers requires that 53receive processing be single-threaded. 54Typically this is done using a dedicated driver 55.Xr taskqueue 9 56thread. 57.Fn ieee80211_input 58and 59.Fn ieee80211_input_all 60process received 802.11 frames and are designed 61for use in that context; e.g. no driver locks may be held. 62.Pp 63The frame passed up in the 64.Vt mbuf 65must have the 802.11 protocol header at the front; all device-specific 66information and/or PLCP must be removed. 67Any CRC must be stripped from the end of the frame. 68The 802.11 protocol header should be 32-bit aligned for 69optimal performance but receive processing does not require it. 70If the frame holds a payload and that is not aligned to a 32-bit 71boundary then the payload will be re-aligned so that it is suitable 72for processing by protocols such as 73.Xr ip 4 . 74.Pp 75If a device (such as 76.Xr ath 4 ) 77inserts padding after the 802.11 header to align 78the payload to a 32-bit boundary the 79.Dv IEEE80211_C_DATAPAD 80capability must be set. 81Otherwise header and payload are assumed contiguous in the mbuf chain. 82.Pp 83If a received frame must pass 84through the A-MPDU receive reorder buffer then the mbuf 85must be marked with the 86.Dv M_AMPDU 87flag. 88Note that for the moment this is required of all frames received from 89a station and TID where a Block ACK stream is active, not just A-MPDU 90aggregates. 91It is sufficient to check for 92.Dv IEEE80211_NODE_HT 93in the 94.Vt ni_flags 95of the station's node table entry, any frames that do not require reorder 96processing will be dispatched with only minimal overhead. 97.Pp 98The 99.Vt rssi 100parameter is the Receive Signal Strength Indication of the frame 101measured in 0.5dBm units relative to the noise floor. 102The 103.Vt noise 104parameter is the best approximation of the noise floor in 105dBm units at the time the frame was received. 106RSSI and noise are used by the 107.Nm net80211 108layer to make scanning and roaming decisions in station mode 109and to do auto channel selection for hostap and similar modes. 110Otherwise the values are made available to user applications 111(with the rssi presented as a filtered average over the last ten values 112and the noise floor the last reported value). 113.Sh SEE ALSO 114.Xr ieee80211 9 115