2 * Copyright (c) 2005-2009 Sam Leffler, Errno Consulting
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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9 * notice, this list of conditions and the following disclaimer.
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27 #ifndef _NET80211_IEEE80211_SCAN_H_
28 #define _NET80211_IEEE80211_SCAN_H_
31 * 802.11 scanning support.
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.
45 * A scan operation involves constructing a set of channels to inspect
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.
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.
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.
72 #define IEEE80211_SCAN_MAX IEEE80211_CHAN_MAX
74 struct ieee80211_scanner; /* scan policy state */
76 struct ieee80211_scan_ssid {
77 int len; /* length in bytes */
78 uint8_t ssid[IEEE80211_NWID_LEN]; /* ssid contents */
80 #define IEEE80211_SCAN_MAX_SSID 1 /* max # ssid's to probe */
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.
91 struct ieee80211_scan_state {
92 struct ieee80211vap *ss_vap;
93 struct ieee80211com *ss_ic;
94 const struct ieee80211_scanner *ss_ops; /* policy hookup, see below */
95 void *ss_priv; /* scanner private state */
97 #define IEEE80211_SCAN_NOPICK 0x0001 /* scan only, no selection */
98 #define IEEE80211_SCAN_ACTIVE 0x0002 /* active scan (probe req) */
99 #define IEEE80211_SCAN_PICK1ST 0x0004 /* ``hey sailor'' mode */
100 #define IEEE80211_SCAN_BGSCAN 0x0008 /* bg scan, exit ps at end */
101 #define IEEE80211_SCAN_ONCE 0x0010 /* do one complete pass */
102 #define IEEE80211_SCAN_NOBCAST 0x0020 /* no broadcast probe req */
103 #define IEEE80211_SCAN_NOJOIN 0x0040 /* no auto-sequencing */
104 #define IEEE80211_SCAN_GOTPICK 0x1000 /* got candidate, can stop */
105 uint8_t ss_nssid; /* # ssid's to probe/match */
106 struct ieee80211_scan_ssid ss_ssid[IEEE80211_SCAN_MAX_SSID];
107 /* ssid's to probe/match */
108 /* ordered channel set */
109 struct ieee80211_channel *ss_chans[IEEE80211_SCAN_MAX];
110 uint16_t ss_next; /* ix of next chan to scan */
111 uint16_t ss_last; /* ix+1 of last chan to scan */
112 unsigned long ss_mindwell; /* min dwell on channel */
113 unsigned long ss_maxdwell; /* max dwell on channel */
117 * The upper 16 bits of the flags word is used to communicate
118 * information to the scanning code that is NOT recorded in
119 * ss_flags. It might be better to split this stuff out into
120 * a separate variable to avoid confusion.
122 #define IEEE80211_SCAN_FLUSH 0x00010000 /* flush candidate table */
123 #define IEEE80211_SCAN_NOSSID 0x80000000 /* don't update ssid list */
126 void ieee80211_scan_attach(struct ieee80211com *);
127 void ieee80211_scan_detach(struct ieee80211com *);
128 void ieee80211_scan_vattach(struct ieee80211vap *);
129 void ieee80211_scan_vdetach(struct ieee80211vap *);
131 void ieee80211_scan_dump_channels(const struct ieee80211_scan_state *);
133 #define IEEE80211_SCAN_FOREVER 0x7fffffff
134 int ieee80211_start_scan(struct ieee80211vap *, int flags,
135 u_int duration, u_int mindwell, u_int maxdwell,
136 u_int nssid, const struct ieee80211_scan_ssid ssids[]);
137 int ieee80211_check_scan(struct ieee80211vap *, int flags,
138 u_int duration, u_int mindwell, u_int maxdwell,
139 u_int nssid, const struct ieee80211_scan_ssid ssids[]);
140 int ieee80211_check_scan_current(struct ieee80211vap *);
141 int ieee80211_bg_scan(struct ieee80211vap *, int);
142 void ieee80211_cancel_scan(struct ieee80211vap *);
143 void ieee80211_cancel_anyscan(struct ieee80211vap *);
144 void ieee80211_scan_next(struct ieee80211vap *);
145 void ieee80211_scan_done(struct ieee80211vap *);
146 void ieee80211_probe_curchan(struct ieee80211vap *, int);
147 struct ieee80211_channel *ieee80211_scan_pickchannel(struct ieee80211com *, int);
149 struct ieee80211_scanparams;
150 void ieee80211_add_scan(struct ieee80211vap *,
151 const struct ieee80211_scanparams *,
152 const struct ieee80211_frame *,
153 int subtype, int rssi, int noise);
154 void ieee80211_scan_timeout(struct ieee80211com *);
156 void ieee80211_scan_assoc_success(struct ieee80211vap *,
157 const uint8_t mac[IEEE80211_ADDR_LEN]);
159 IEEE80211_SCAN_FAIL_TIMEOUT = 1, /* no response to mgmt frame */
160 IEEE80211_SCAN_FAIL_STATUS = 2 /* negative response to " " */
162 void ieee80211_scan_assoc_fail(struct ieee80211vap *,
163 const uint8_t mac[IEEE80211_ADDR_LEN], int reason);
164 void ieee80211_scan_flush(struct ieee80211vap *);
166 struct ieee80211_scan_entry;
167 typedef void ieee80211_scan_iter_func(void *,
168 const struct ieee80211_scan_entry *);
169 void ieee80211_scan_iterate(struct ieee80211vap *,
170 ieee80211_scan_iter_func, void *);
172 IEEE80211_BPARSE_BADIELEN = 0x01, /* ie len past end of frame */
173 IEEE80211_BPARSE_RATES_INVALID = 0x02, /* invalid RATES ie */
174 IEEE80211_BPARSE_XRATES_INVALID = 0x04, /* invalid XRATES ie */
175 IEEE80211_BPARSE_SSID_INVALID = 0x08, /* invalid SSID ie */
176 IEEE80211_BPARSE_CHAN_INVALID = 0x10, /* invalid FH/DSPARMS chan */
177 IEEE80211_BPARSE_OFFCHAN = 0x20, /* DSPARMS chan != curchan */
178 IEEE80211_BPARSE_BINTVAL_INVALID= 0x40, /* invalid beacon interval */
179 IEEE80211_BPARSE_CSA_INVALID = 0x80, /* invalid CSA ie */
183 * Parameters supplied when adding/updating an entry in a
184 * scan cache. Pointer variables should be set to NULL
185 * if no data is available. Pointer references can be to
186 * local data; any information that is saved will be copied.
187 * All multi-byte values must be in host byte order.
189 struct ieee80211_scanparams {
190 uint8_t status; /* bitmask of IEEE80211_BPARSE_* */
191 uint8_t chan; /* channel # from FH/DSPARMS */
192 uint8_t bchan; /* curchan's channel # */
194 uint16_t fhdwell; /* FHSS dwell interval */
195 uint16_t capinfo; /* 802.11 capabilities */
196 uint16_t erp; /* NB: 0x100 indicates ie present */
199 uint8_t *ies; /* all captured ies */
200 size_t ies_len; /* length of all captured ies */
222 * Scan cache entry format used when exporting data from a policy
223 * module; this data may be represented some other way internally.
225 struct ieee80211_scan_entry {
226 uint8_t se_macaddr[IEEE80211_ADDR_LEN];
227 uint8_t se_bssid[IEEE80211_ADDR_LEN];
228 /* XXX can point inside se_ies */
229 uint8_t se_ssid[2+IEEE80211_NWID_LEN];
230 uint8_t se_rates[2+IEEE80211_RATE_MAXSIZE];
231 uint8_t se_xrates[2+IEEE80211_RATE_MAXSIZE];
235 } se_tstamp; /* from last rcv'd beacon */
236 uint16_t se_intval; /* beacon interval (host byte order) */
237 uint16_t se_capinfo; /* capabilities (host byte order) */
238 struct ieee80211_channel *se_chan;/* channel where sta found */
239 uint16_t se_timoff; /* byte offset to TIM ie */
240 uint16_t se_fhdwell; /* FH only (host byte order) */
241 uint8_t se_fhindex; /* FH only */
242 uint8_t se_dtimperiod; /* DTIM period */
243 uint16_t se_erp; /* ERP from beacon/probe resp */
244 int8_t se_rssi; /* avg'd recv ssi */
245 int8_t se_noise; /* noise floor */
246 uint8_t se_cc[2]; /* captured country code */
247 uint8_t se_meshid[2+IEEE80211_MESHID_LEN];
248 struct ieee80211_ies se_ies; /* captured ie's */
249 u_int se_age; /* age of entry (0 on create) */
251 MALLOC_DECLARE(M_80211_SCAN);
254 * Template for an in-kernel scan policy module.
255 * Modules register with the scanning code and are
256 * typically loaded as needed.
258 struct ieee80211_scanner {
259 const char *scan_name; /* printable name */
260 int (*scan_attach)(struct ieee80211_scan_state *);
261 int (*scan_detach)(struct ieee80211_scan_state *);
262 int (*scan_start)(struct ieee80211_scan_state *,
263 struct ieee80211vap *);
264 int (*scan_restart)(struct ieee80211_scan_state *,
265 struct ieee80211vap *);
266 int (*scan_cancel)(struct ieee80211_scan_state *,
267 struct ieee80211vap *);
268 int (*scan_end)(struct ieee80211_scan_state *,
269 struct ieee80211vap *);
270 int (*scan_flush)(struct ieee80211_scan_state *);
271 struct ieee80211_channel *(*scan_pickchan)(
272 struct ieee80211_scan_state *, int);
273 /* add an entry to the cache */
274 int (*scan_add)(struct ieee80211_scan_state *,
275 const struct ieee80211_scanparams *,
276 const struct ieee80211_frame *,
277 int subtype, int rssi, int noise);
278 /* age and/or purge entries in the cache */
279 void (*scan_age)(struct ieee80211_scan_state *);
280 /* note that association failed for an entry */
281 void (*scan_assoc_fail)(struct ieee80211_scan_state *,
282 const uint8_t macaddr[IEEE80211_ADDR_LEN],
284 /* note that association succeed for an entry */
285 void (*scan_assoc_success)(struct ieee80211_scan_state *,
286 const uint8_t macaddr[IEEE80211_ADDR_LEN]);
287 /* iterate over entries in the scan cache */
288 void (*scan_iterate)(struct ieee80211_scan_state *,
289 ieee80211_scan_iter_func *, void *);
290 void (*scan_spare0)(void);
291 void (*scan_spare1)(void);
292 void (*scan_spare2)(void);
293 void (*scan_spare4)(void);
295 void ieee80211_scanner_register(enum ieee80211_opmode,
296 const struct ieee80211_scanner *);
297 void ieee80211_scanner_unregister(enum ieee80211_opmode,
298 const struct ieee80211_scanner *);
299 void ieee80211_scanner_unregister_all(const struct ieee80211_scanner *);
300 const struct ieee80211_scanner *ieee80211_scanner_get(enum ieee80211_opmode);
301 #endif /* _NET80211_IEEE80211_SCAN_H_ */