ieee80211_scan.h revision 186904
1/*- 2 * Copyright (c) 2005-2009 Sam Leffler, Errno Consulting 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 * 25 * $FreeBSD: head/sys/net80211/ieee80211_scan.h 186904 2009-01-08 17:12:47Z sam $ 26 */ 27#ifndef _NET80211_IEEE80211_SCAN_H_ 28#define _NET80211_IEEE80211_SCAN_H_ 29 30/* 31 * 802.11 scanning support. 32 * 33 * Scanning is the procedure by which a station locates a bss to join 34 * (infrastructure/ibss mode), or a channel to use (when operating as 35 * an ap or ibss master). Scans are either "active" or "passive". An 36 * active scan causes one or more probe request frames to be sent on 37 * visiting each channel. A passive request causes each channel in the 38 * scan set to be visited but no frames to be transmitted; the station 39 * only listens for traffic. Note that active scanning may still need 40 * to listen for traffic before sending probe request frames depending 41 * on regulatory constraints; the 802.11 layer handles this by generating 42 * a callback when scanning on a ``passive channel'' when the 43 * IEEE80211_FEXT_PROBECHAN flag is set. 44 * 45 * A scan operation involves constructing a set of channels to inspec 46 * (the scan set), visiting each channel and collecting information 47 * (e.g. what bss are present), and then analyzing the results to make 48 * decisions like which bss to join. This process needs to be as fast 49 * as possible so we do things like intelligently construct scan sets 50 * and dwell on a channel only as long as necessary. The scan code also 51 * maintains a cache of recent scan results and uses it to bypass scanning 52 * whenever possible. The scan cache is also used to enable roaming 53 * between access points when operating in infrastructure mode. 54 * 55 * Scanning is handled with pluggable modules that implement "policy" 56 * per-operating mode. The core scanning support provides an 57 * instrastructure to support these modules and exports a common api 58 * to the rest of the 802.11 layer. Policy modules decide what 59 * channels to visit, what state to record to make decisions (e.g. ap 60 * mode scanning for auto channel selection keeps significantly less 61 * state than sta mode scanning for an ap to associate to), and selects 62 * the final station/channel to return as the result of a scan. 63 * 64 * Scanning is done synchronously when initially bringing a vap to an 65 * operational state and optionally in the background to maintain the 66 * scan cache for doing roaming and rogue ap monitoring. Scanning is 67 * not tied to the 802.11 state machine that governs vaps though there 68 * is linkage to the IEEE80211_SCAN state. Only one vap at a time may 69 * be scanning; this scheduling policy is handled in ieee80211_new_state 70 * and is invisible to the scanning code. 71*/ 72#define IEEE80211_SCAN_MAX IEEE80211_CHAN_MAX 73 74struct ieee80211_scanner; /* scan policy state */ 75 76struct ieee80211_scan_ssid { 77 int len; /* length in bytes */ 78 uint8_t ssid[IEEE80211_NWID_LEN]; /* ssid contents */ 79}; 80#define IEEE80211_SCAN_MAX_SSID 1 /* max # ssid's to probe */ 81 82/* 83 * Scan state visible to the 802.11 layer. Scan parameters and 84 * results are stored in this data structure. The ieee80211_scan_state 85 * structure is extended with space that is maintained private to 86 * the core scanning support. We allocate one instance and link it 87 * to the ieee80211com structure; then share it between all associated 88 * vaps. We could allocate multiple of these, e.g. to hold multiple 89 * scan results, but this is sufficient for current needs. 90 */ 91struct ieee80211_scan_state { 92 struct ieee80211vap *ss_vap; 93 const struct ieee80211_scanner *ss_ops; /* policy hookup, see below */ 94 void *ss_priv; /* scanner private state */ 95 uint16_t ss_flags; 96#define IEEE80211_SCAN_NOPICK 0x0001 /* scan only, no selection */ 97#define IEEE80211_SCAN_ACTIVE 0x0002 /* active scan (probe req) */ 98#define IEEE80211_SCAN_PICK1ST 0x0004 /* ``hey sailor'' mode */ 99#define IEEE80211_SCAN_BGSCAN 0x0008 /* bg scan, exit ps at end */ 100#define IEEE80211_SCAN_ONCE 0x0010 /* do one complete pass */ 101#define IEEE80211_SCAN_NOBCAST 0x0020 /* no broadcast probe req */ 102#define IEEE80211_SCAN_NOJOIN 0x0040 /* no auto-sequencing */ 103#define IEEE80211_SCAN_GOTPICK 0x1000 /* got candidate, can stop */ 104 uint8_t ss_nssid; /* # ssid's to probe/match */ 105 struct ieee80211_scan_ssid ss_ssid[IEEE80211_SCAN_MAX_SSID]; 106 /* ssid's to probe/match */ 107 /* ordered channel set */ 108 struct ieee80211_channel *ss_chans[IEEE80211_SCAN_MAX]; 109 uint16_t ss_next; /* ix of next chan to scan */ 110 uint16_t ss_last; /* ix+1 of last chan to scan */ 111 unsigned long ss_mindwell; /* min dwell on channel */ 112 unsigned long ss_maxdwell; /* max dwell on channel */ 113}; 114 115/* 116 * The upper 16 bits of the flags word is used to communicate 117 * information to the scanning code that is NOT recorded in 118 * ss_flags. It might be better to split this stuff out into 119 * a separate variable to avoid confusion. 120 */ 121#define IEEE80211_SCAN_FLUSH 0x00010000 /* flush candidate table */ 122#define IEEE80211_SCAN_NOSSID 0x80000000 /* don't update ssid list */ 123 124struct ieee80211com; 125void ieee80211_scan_attach(struct ieee80211com *); 126void ieee80211_scan_detach(struct ieee80211com *); 127void ieee80211_scan_vattach(struct ieee80211vap *); 128void ieee80211_scan_vdetach(struct ieee80211vap *); 129 130void ieee80211_scan_dump_channels(const struct ieee80211_scan_state *); 131 132#define IEEE80211_SCAN_FOREVER 0x7fffffff 133int ieee80211_start_scan(struct ieee80211vap *, int flags, 134 u_int duration, u_int mindwell, u_int maxdwell, 135 u_int nssid, const struct ieee80211_scan_ssid ssids[]); 136int ieee80211_check_scan(struct ieee80211vap *, int flags, 137 u_int duration, u_int mindwell, u_int maxdwell, 138 u_int nssid, const struct ieee80211_scan_ssid ssids[]); 139int ieee80211_check_scan_current(struct ieee80211vap *); 140int ieee80211_bg_scan(struct ieee80211vap *, int); 141void ieee80211_cancel_scan(struct ieee80211vap *); 142void ieee80211_cancel_anyscan(struct ieee80211vap *); 143void ieee80211_scan_next(struct ieee80211vap *); 144void ieee80211_scan_done(struct ieee80211vap *); 145void ieee80211_probe_curchan(struct ieee80211vap *, int); 146struct ieee80211_channel *ieee80211_scan_pickchannel(struct ieee80211com *, int); 147 148struct ieee80211_scanparams; 149void ieee80211_add_scan(struct ieee80211vap *, 150 const struct ieee80211_scanparams *, 151 const struct ieee80211_frame *, 152 int subtype, int rssi, int noise, int rstamp); 153void ieee80211_scan_timeout(struct ieee80211com *); 154 155void ieee80211_scan_assoc_success(struct ieee80211vap *, 156 const uint8_t mac[IEEE80211_ADDR_LEN]); 157enum { 158 IEEE80211_SCAN_FAIL_TIMEOUT = 1, /* no response to mgmt frame */ 159 IEEE80211_SCAN_FAIL_STATUS = 2 /* negative response to " " */ 160}; 161void ieee80211_scan_assoc_fail(struct ieee80211vap *, 162 const uint8_t mac[IEEE80211_ADDR_LEN], int reason); 163void ieee80211_scan_flush(struct ieee80211vap *); 164 165struct ieee80211_scan_entry; 166typedef void ieee80211_scan_iter_func(void *, 167 const struct ieee80211_scan_entry *); 168void ieee80211_scan_iterate(struct ieee80211vap *, 169 ieee80211_scan_iter_func, void *); 170enum { 171 IEEE80211_BPARSE_BADIELEN = 0x01, /* ie len past end of frame */ 172 IEEE80211_BPARSE_RATES_INVALID = 0x02, /* invalid RATES ie */ 173 IEEE80211_BPARSE_XRATES_INVALID = 0x04, /* invalid XRATES ie */ 174 IEEE80211_BPARSE_SSID_INVALID = 0x08, /* invalid SSID ie */ 175 IEEE80211_BPARSE_CHAN_INVALID = 0x10, /* invalid FH/DSPARMS chan */ 176 IEEE80211_BPARSE_OFFCHAN = 0x20, /* DSPARMS chan != curchan */ 177 IEEE80211_BPARSE_BINTVAL_INVALID= 0x40, /* invalid beacon interval */ 178}; 179 180/* 181 * Parameters supplied when adding/updating an entry in a 182 * scan cache. Pointer variables should be set to NULL 183 * if no data is available. Pointer references can be to 184 * local data; any information that is saved will be copied. 185 * All multi-byte values must be in host byte order. 186 */ 187struct ieee80211_scanparams { 188 uint8_t status; /* bitmask of IEEE80211_BPARSE_* */ 189 uint8_t chan; /* channel # from FH/DSPARMS */ 190 uint8_t bchan; /* curchan's channel # */ 191 uint8_t fhindex; 192 uint16_t fhdwell; /* FHSS dwell interval */ 193 uint16_t capinfo; /* 802.11 capabilities */ 194 uint16_t erp; /* NB: 0x100 indicates ie present */ 195 uint16_t bintval; 196 uint8_t timoff; 197 uint8_t *ies; /* all captured ies */ 198 size_t ies_len; /* length of all captured ies */ 199 uint8_t *tim; 200 uint8_t *tstamp; 201 uint8_t *country; 202 uint8_t *ssid; 203 uint8_t *rates; 204 uint8_t *xrates; 205 uint8_t *doth; 206 uint8_t *wpa; 207 uint8_t *rsn; 208 uint8_t *wme; 209 uint8_t *htcap; 210 uint8_t *htinfo; 211 uint8_t *ath; 212 uint8_t *tdma; 213}; 214 215/* 216 * Scan cache entry format used when exporting data from a policy 217 * module; this data may be represented some other way internally. 218 */ 219struct ieee80211_scan_entry { 220 uint8_t se_macaddr[IEEE80211_ADDR_LEN]; 221 uint8_t se_bssid[IEEE80211_ADDR_LEN]; 222 /* XXX can point inside se_ies */ 223 uint8_t se_ssid[2+IEEE80211_NWID_LEN]; 224 uint8_t se_rates[2+IEEE80211_RATE_MAXSIZE]; 225 uint8_t se_xrates[2+IEEE80211_RATE_MAXSIZE]; 226 uint32_t se_rstamp; /* recv timestamp */ 227 union { 228 uint8_t data[8]; 229 u_int64_t tsf; 230 } se_tstamp; /* from last rcv'd beacon */ 231 uint16_t se_intval; /* beacon interval (host byte order) */ 232 uint16_t se_capinfo; /* capabilities (host byte order) */ 233 struct ieee80211_channel *se_chan;/* channel where sta found */ 234 uint16_t se_timoff; /* byte offset to TIM ie */ 235 uint16_t se_fhdwell; /* FH only (host byte order) */ 236 uint8_t se_fhindex; /* FH only */ 237 uint8_t se_dtimperiod; /* DTIM period */ 238 uint16_t se_erp; /* ERP from beacon/probe resp */ 239 int8_t se_rssi; /* avg'd recv ssi */ 240 int8_t se_noise; /* noise floor */ 241 uint8_t se_cc[2]; /* captured country code */ 242 struct ieee80211_ies se_ies; /* captured ie's */ 243 u_int se_age; /* age of entry (0 on create) */ 244}; 245MALLOC_DECLARE(M_80211_SCAN); 246 247/* 248 * Template for an in-kernel scan policy module. 249 * Modules register with the scanning code and are 250 * typically loaded as needed. 251 */ 252struct ieee80211_scanner { 253 const char *scan_name; /* printable name */ 254 int (*scan_attach)(struct ieee80211_scan_state *); 255 int (*scan_detach)(struct ieee80211_scan_state *); 256 int (*scan_start)(struct ieee80211_scan_state *, 257 struct ieee80211vap *); 258 int (*scan_restart)(struct ieee80211_scan_state *, 259 struct ieee80211vap *); 260 int (*scan_cancel)(struct ieee80211_scan_state *, 261 struct ieee80211vap *); 262 int (*scan_end)(struct ieee80211_scan_state *, 263 struct ieee80211vap *); 264 int (*scan_flush)(struct ieee80211_scan_state *); 265 struct ieee80211_channel *(*scan_pickchan)( 266 struct ieee80211_scan_state *, int); 267 /* add an entry to the cache */ 268 int (*scan_add)(struct ieee80211_scan_state *, 269 const struct ieee80211_scanparams *, 270 const struct ieee80211_frame *, 271 int subtype, int rssi, int noise, int rstamp); 272 /* age and/or purge entries in the cache */ 273 void (*scan_age)(struct ieee80211_scan_state *); 274 /* note that association failed for an entry */ 275 void (*scan_assoc_fail)(struct ieee80211_scan_state *, 276 const uint8_t macaddr[IEEE80211_ADDR_LEN], 277 int reason); 278 /* note that association succeed for an entry */ 279 void (*scan_assoc_success)(struct ieee80211_scan_state *, 280 const uint8_t macaddr[IEEE80211_ADDR_LEN]); 281 /* iterate over entries in the scan cache */ 282 void (*scan_iterate)(struct ieee80211_scan_state *, 283 ieee80211_scan_iter_func *, void *); 284}; 285void ieee80211_scanner_register(enum ieee80211_opmode, 286 const struct ieee80211_scanner *); 287void ieee80211_scanner_unregister(enum ieee80211_opmode, 288 const struct ieee80211_scanner *); 289void ieee80211_scanner_unregister_all(const struct ieee80211_scanner *); 290const struct ieee80211_scanner *ieee80211_scanner_get(enum ieee80211_opmode); 291#endif /* _NET80211_IEEE80211_SCAN_H_ */ 292