| ieee80211_output.9 (147647) | ieee80211_output.9 (196155) |
|---|---|
| 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: --- 10 unchanged lines hidden (view full) --- 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.\" | 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: --- 10 unchanged lines hidden (view full) --- 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.\" $FreeBSD: head/share/man/man9/ieee80211_output.9 147647 2005-06-28 20:15:19Z hmp $ | 27.\" $FreeBSD: head/share/man/man9/ieee80211_output.9 196155 2009-08-12 21:03:16Z sam $ |
| 28.\" $Id: ieee80211_output.9,v 1.5 2004/03/04 12:31:18 bruce Exp $ 29.\" | 28.\" $Id: ieee80211_output.9,v 1.5 2004/03/04 12:31:18 bruce Exp $ 29.\" |
| 30.Dd March 2, 2004 | 30.Dd August 4, 2009 |
| 31.Dt IEEE80211_OUTPUT 9 32.Os 33.Sh NAME | 31.Dt IEEE80211_OUTPUT 9 32.Os 33.Sh NAME |
| 34.Nm ieee80211_encap , ieee80211_add_rates , 35.Nm ieee80211_add_xrates , ieee80211_send_mgmt | 34.Nm ieee80211_output |
| 36.Nd software 802.11 stack output functions 37.Sh SYNOPSIS 38.In net80211/ieee80211_var.h | 35.Nd software 802.11 stack output functions 36.Sh SYNOPSIS 37.In net80211/ieee80211_var.h |
| 39.In net80211/ieee80211_proto.h 40.Ft struct mbuf * 41.Fo ieee80211_encap 42.Fa "struct ifnet *ifp" "struct mbuf *m" "struct ieee80211_node **pni" 43.Fc 44.Ft u_int8_t * 45.Fn ieee80211_add_rates "u_int8_t *frm" "const struct ieee80211_rateset *rs" 46.Ft u_int8_t * 47.Fn ieee80211_add_xrates "u_int8_t *frm" "const struct ieee80211_rateset *rs" | 38.\" |
| 48.Ft int | 39.Ft int |
| 49.Fo ieee80211_send_mgmt 50.Fa "struct ieee80211com *ic" "struct ieee80211_node *ni" "int type" "int arg" | 40.Fn M_WME_GETAC "struct mbuf *" 41.\" 42.Ft int 43.Fn M_SEQNO_GET "struct mbuf *" 44.\" 45.Ft struct ieee80211_key * 46.Fn ieee80211_crypto_encap "struct ieee80211_node *" "struct mbuf *" 47.\" 48.Ft void 49.Fo ieee80211_process_callback 50.Fa struct ieee80211_node * 51.Fa struct mbuf * 52.Fa int |
| 51.Fc 52.Sh DESCRIPTION | 53.Fc 54.Sh DESCRIPTION |
| 53These functions handle the encapsulation and transmission of 802.11 frames 54within the software 802.11 stack. 55.Pp | |
| 56The | 55The |
| 57.Fn ieee80211_encap 58function encapsulates an outbound data frame contained within the 59mbuf chain 60.Fa m 61from the interface 62.Fa ifp . 63The argument 64.Fa *pni 65is a reference to the destination node. | 56.Nm net80211 57layer that supports 802.11 device drivers handles most of the 58work required to transmit frames. 59Drivers usually receive fully-encapsulated 802.11 frames that 60have been classified and assigned a transmit priority; 61all that is left is to do 62crypto encapsulation, 63prepare any hardware-specific state, 64and 65push the packet out to the device. 66Outbound frames are either generated by the 67.Nm net80211 68layer (e.g. management frames) or are passed down 69from upper layers through the 70.Xr ifnet 9 71transmit queue. 72Data frames passed down for transmit flow through 73.Nm net80211 74which handles aggregation, 802.11 encapsulation, and then 75dispatches the frames to the driver through it's transmit queue. |
| 66.Pp | 76.Pp |
| 67If the function is successful, the mbuf chain is updated with the 68802.11 frame header prepended, and a pointer to the head of the chain 69is returned. 70If an error occurs, 71.Dv NULL 72will be returned, and 73.Fa *pni 74is also set to 75.Dv NULL . 76The caller is responsible for freeing the node reference if 77.Fa *pni 78is 79.Pf non- Dv NULL 80on return. 81The convention is that 82.Va ic_bss 83is not reference counted; the caller is responsible for maintaining this 84reference count. | 77There are two control paths by which frames reach a driver for transmit. 78Data packets are queued to the device's 79.Vt if_snd 80queue and the driver's 81.Vt if_start 82method is called. 83Other frames are passed down using the 84.Vt ic_raw_xmit 85method without queueing (unless done by the driver). 86The raw transmit path may include data frames from user applications 87that inject them through 88.Xr bpf 4 89and NullData frames generated by 90.Nm net80211 91to probe for idle stations (when operating as an access point). |
| 85.Pp | 92.Pp |
| 86.\" 87The 88.Fn ieee80211_add_rates 89utility function is used to add the rate set element 90.Fa *rs 91to the frame 92.Fa frm . 93A pointer to the location in the buffer after the addition of the rate set 94is returned. 95It is typically used when constructing management frames from within the 96software 802.11 stack. | 93.Nm net80211 94handles all state-related bookkeeping and management for the handling 95of data frames. 96Data frames are only transmit for a vap in the 97.Dv IEEE80211_S_RUN 98state; there is no need, for example, to check for frames sent down 99when CAC or CSA is active. 100Similarly, 101.Nm net80211 102handles activities such as background scanning and power save mode, 103frames will not be sent to a driver unless it is operating on the 104BSS channel will 105.Dq full power . |
| 97.Pp | 106.Pp |
| 98.\" 99The 100.Fn ieee80211_add_xrates 101utility function is used to add the extended rate set element 102.Fa *rs 103to the frame 104.Fa frm . 105A pointer to the location in the buffer after the addition of the rate set 106is returned. 107It is typically used when constructing management frames from within the 108software 802.11 stack in 802.11g mode. | 107All frames passed to a driver for transmit hold a reference to a 108node table entry in the 109.Vt m_pkthdr.rcvif 110field. 111The node is associated with the frame destination. 112Typically it is the receiver's entry but in some situations it may be 113a placeholder entry or the 114.Dq next hop station 115(such as in a mesh network). 116In all cases the reference must be reclaimed with 117.Fn ieee80211_free_node 118when the transmit work is completed. 119The rule to remember is: 120.Nm net80211 121passes responsibility for the 122.Vt mbuf 123and 124.Dq node reference 125to the driver with each frame it hands off for transmit. 126.Sh PACKET CLASSIFICATION 127All frames passed by 128.Nm net80211 129for transmit are assigned a priority based on any vlan tag 130assigned to the receiving station and/or any Diffserv setting 131in an IP or IPv6 header. 132If both vlan and Diffserv priority are present the higher of the 133two is used. 134If WME/WMM is being used then any ACM policy (in station mode) is 135also enforced. 136The resulting AC is attached to the mbuf and may be read back using the 137.Fn M_WME_GETAC 138macro. |
| 109.Pp | 139.Pp |
| 110.\" | 140PAE/EAPOL frames are tagged with an 141.Dv M_EAPOL 142mbuf flag; drivers should transmit them with care, usually by 143using the transmit rate for management frames. 144Multicast/broadcast frames are marked with the 145.Dv M_MCAST 146mbuf flag. 147Frames coming out of a station's power save queue and that have 148more frames immediately following are marked with the 149.Dv M_MORE_DATA 150mbuf flag. 151Such frames will be queued consecutively in the driver's 152.Vt if_snd 153queue and drivers should preserve the ordering when passing 154them to the device. 155.Sh FRAGMENTED FRAMES |
| 111The | 156The |
| 112.Fn ieee80211_send_mgmt 113function transmits a management frame on the interface 114.Fa ic 115to the destination node 116.Fa ni 117of type 118.Fa type . 119.Pp 120The argument 121.Fa arg 122specifies either a sequence number for authentication operations, 123a status code for [re]association operations, 124or a reason for deauthentication and deassociation operations. 125.Pp 126Nodes other than 127.Va ic_bss 128have their reference count incremented to reflect their use for an 129indeterminate amount of time. 130This reference is freed when the function returns. 131.Pp 132The function returns 0 if successful; if temporary buffer space is not 133available, the function returns 134.Er ENOMEM . 135.\" | 157.Nm net80211 158layer will fragment data frames according to the setting of 159.Vt iv_fragthreshold 160if a driver marks the 161.Dv IEEE80211_C_TXFRAG 162capability. 163Fragmented frames are placed 164in the devices transmit queue with the fragments chained together with 165.Vt m_nextpkt . 166Each frame is marked with the 167.Dv M_FRAG 168mbuf flag, and the first and last are marked with 169.Dv M_FIRSTFRAG 170and 171.Dv M_LASTFRAG , 172respectively. 173Drivers are expected to process all fragments or none. 174.Sh TRANSMIT CALLBACKS 175Frames sent by 176.Nm net80211 177may be tagged with the 178.Dv M_TXCB 179mbuf flag to indicate a callback should be done 180when their transmission completes. 181The callback is done using 182.Fn ieee80211_process_callback 183with the last parameter set to a non-zero value if an error occurred 184and zero otherwise. 185Note 186.Nm net80211 187understands that drivers may be incapable of determining status; 188a device may not report if an ACK frame is received and/or a device may queue 189transmit requests in its hardware and only report status on whether 190the frame was successfully queued. |
| 136.Sh SEE ALSO | 191.Sh SEE ALSO |
| 192.Xr bpf 4 |
|
| 137.Xr ieee80211 9 , 138.Xr ifnet 9 | 193.Xr ieee80211 9 , 194.Xr ifnet 9 |
| 139.Sh HISTORY 140The 141.Nm ieee80211 142series of functions first appeared in 143.Nx 1.5 , 144and were later ported to 145.Fx 4.6 . 146.Sh AUTHORS 147.An -nosplit 148This manual page was written by 149.An Bruce M. Simpson Aq bms@FreeBSD.org 150and 151.An Darron Broad Aq darron@kewl.org . | |