sys/netproto/802_11/ieee80211_scan.h

   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 195618 2009-07-11 15:02:45Z rpaulo $
  26  * $DragonFly$
  27  */
  28 #ifndef _NET80211_IEEE80211_SCAN_H_
  29 #define _NET80211_IEEE80211_SCAN_H_
  30
  31 /*
  32  * 802.11 scanning support.
  33  *
  34  * Scanning is the procedure by which a station locates a bss to join
  35  * (infrastructure/ibss mode), or a channel to use (when operating as
  36  * an ap or ibss master).  Scans are either "active" or "passive".  An
  37  * active scan causes one or more probe request frames to be sent on
  38  * visiting each channel.  A passive request causes each channel in the
  39  * scan set to be visited but no frames to be transmitted; the station
  40  * only listens for traffic.  Note that active scanning may still need
  41  * to listen for traffic before sending probe request frames depending
  42  * on regulatory constraints; the 802.11 layer handles this by generating
  43  * a callback when scanning on a ``passive channel'' when the
  44  * IEEE80211_FEXT_PROBECHAN flag is set.
  45  *
  46  * A scan operation involves constructing a set of channels to inspect
  47  * (the scan set), visiting each channel and collecting information
  48  * (e.g. what bss are present), and then analyzing the results to make
  49  * decisions like which bss to join.  This process needs to be as fast
  50  * as possible so we do things like intelligently construct scan sets
  51  * and dwell on a channel only as long as necessary.  The scan code also
  52  * maintains a cache of recent scan results and uses it to bypass scanning
  53  * whenever possible.  The scan cache is also used to enable roaming
  54  * between access points when operating in infrastructure mode.
  55  *
  56  * Scanning is handled with pluggable modules that implement "policy"
  57  * per-operating mode.  The core scanning support provides an
  58  * instrastructure to support these modules and exports a common api
  59  * to the rest of the 802.11 layer.  Policy modules decide what
  60  * channels to visit, what state to record to make decisions (e.g. ap
  61  * mode scanning for auto channel selection keeps significantly less
  62  * state than sta mode scanning for an ap to associate to), and selects
  63  * the final station/channel to return as the result of a scan.
  64  *
  65  * Scanning is done synchronously when initially bringing a vap to an
  66  * operational state and optionally in the background to maintain the
  67  * scan cache for doing roaming and rogue ap monitoring.  Scanning is
  68  * not tied to the 802.11 state machine that governs vaps though there
  69  * is linkage to the IEEE80211_SCAN state.  Only one vap at a time may
  70  * be scanning; this scheduling policy is handled in ieee80211_new_state
  71  * and is invisible to the scanning code.
  72 */
  73 #define IEEE80211_SCAN_MAX      IEEE80211_CHAN_MAX
  74
  75 struct ieee80211_scanner;                       /* scan policy state */
  76
  77 struct ieee80211_scan_ssid {
  78         int      len;                           /* length in bytes */
  79         uint8_t ssid[IEEE80211_NWID_LEN];       /* ssid contents */
  80 };
  81 #define IEEE80211_SCAN_MAX_SSID 1               /* max # ssid's to probe */
  82
  83 /*
  84  * Scan state visible to the 802.11 layer.  Scan parameters and
  85  * results are stored in this data structure.  The ieee80211_scan_state
  86  * structure is extended with space that is maintained private to
  87  * the core scanning support.  We allocate one instance and link it
  88  * to the ieee80211com structure; then share it between all associated
  89  * vaps.  We could allocate multiple of these, e.g. to hold multiple
  90  * scan results, but this is sufficient for current needs.
  91  */
  92 struct ieee80211_scan_state {
  93         struct ieee80211vap *ss_vap;
  94         struct ieee80211com *ss_ic;
  95         const struct ieee80211_scanner *ss_ops; /* policy hookup, see below */
  96         void            *ss_priv;               /* scanner private state */
  97         uint16_t        ss_flags;
  98 #define IEEE80211_SCAN_NOPICK   0x0001          /* scan only, no selection */
  99 #define IEEE80211_SCAN_ACTIVE   0x0002          /* active scan (probe req) */
 100 #define IEEE80211_SCAN_PICK1ST  0x0004          /* ``hey sailor'' mode */
 101 #define IEEE80211_SCAN_BGSCAN   0x0008          /* bg scan, exit ps at end */
 102 #define IEEE80211_SCAN_ONCE     0x0010          /* do one complete pass */
 103 #define IEEE80211_SCAN_NOBCAST  0x0020          /* no broadcast probe req */
 104 #define IEEE80211_SCAN_NOJOIN   0x0040          /* no auto-sequencing */
 105 #define IEEE80211_SCAN_GOTPICK  0x1000          /* got candidate, can stop */
 106         uint8_t         ss_nssid;               /* # ssid's to probe/match */
 107         struct ieee80211_scan_ssid ss_ssid[IEEE80211_SCAN_MAX_SSID];
 108                                                 /* ssid's to probe/match */
 109                                                 /* ordered channel set */
 110         struct ieee80211_channel *ss_chans[IEEE80211_SCAN_MAX];
 111         uint16_t        ss_next;                /* ix of next chan to scan */
 112         uint16_t        ss_last;                /* ix+1 of last chan to scan */
 113         unsigned long   ss_mindwell;            /* min dwell on channel */
 114         unsigned long   ss_maxdwell;            /* max dwell on channel */
 115 };
 116
 117 /*
 118  * The upper 16 bits of the flags word is used to communicate
 119  * information to the scanning code that is NOT recorded in
 120  * ss_flags.  It might be better to split this stuff out into
 121  * a separate variable to avoid confusion.
 122  */
 123 #define IEEE80211_SCAN_FLUSH    0x00010000      /* flush candidate table */
 124 #define IEEE80211_SCAN_NOSSID   0x80000000      /* don't update ssid list */
 125
 126 struct ieee80211com;
 127 void    ieee80211_scan_attach(struct ieee80211com *);
 128 void    ieee80211_scan_detach(struct ieee80211com *);
 129 void    ieee80211_scan_vattach(struct ieee80211vap *);
 130 void    ieee80211_scan_vdetach(struct ieee80211vap *);
 131
 132 void    ieee80211_scan_dump_channels(const struct ieee80211_scan_state *);
 133
 134 #define IEEE80211_SCAN_FOREVER  0x7fffffff
 135 int     ieee80211_start_scan(struct ieee80211vap *, int flags,
 136                 u_int duration, u_int mindwell, u_int maxdwell,
 137                 u_int nssid, const struct ieee80211_scan_ssid ssids[]);
 138 int     ieee80211_check_scan(struct ieee80211vap *, int flags,
 139                 u_int duration, u_int mindwell, u_int maxdwell,
 140                 u_int nssid, const struct ieee80211_scan_ssid ssids[]);
 141 int     ieee80211_check_scan_current(struct ieee80211vap *);
 142 int     ieee80211_bg_scan(struct ieee80211vap *, int);
 143 void    ieee80211_cancel_scan(struct ieee80211vap *);
 144 void    ieee80211_cancel_anyscan(struct ieee80211vap *);
 145 void    ieee80211_scan_next(struct ieee80211vap *);
 146 void    ieee80211_scan_done(struct ieee80211vap *);
 147 void    ieee80211_probe_curchan(struct ieee80211vap *, int);
 148 struct ieee80211_channel *ieee80211_scan_pickchannel(struct ieee80211com *, int);
 149
 150 struct ieee80211_scanparams;
 151 void    ieee80211_add_scan(struct ieee80211vap *,
 152                 const struct ieee80211_scanparams *,
 153                 const struct ieee80211_frame *,
 154                 int subtype, int rssi, int noise);
 155 void    ieee80211_scan_timeout(struct ieee80211com *);
 156
 157 void    ieee80211_scan_assoc_success(struct ieee80211vap *,
 158                 const uint8_t mac[IEEE80211_ADDR_LEN]);
 159 enum {
 160         IEEE80211_SCAN_FAIL_TIMEOUT     = 1,    /* no response to mgmt frame */
 161         IEEE80211_SCAN_FAIL_STATUS      = 2     /* negative response to " " */
 162 };
 163 void    ieee80211_scan_assoc_fail(struct ieee80211vap *,
 164                 const uint8_t mac[IEEE80211_ADDR_LEN], int reason);
 165 void    ieee80211_scan_flush(struct ieee80211vap *);
 166
 167 struct ieee80211_scan_entry;
 168 typedef void ieee80211_scan_iter_func(void *,
 169                 const struct ieee80211_scan_entry *);
 170 void    ieee80211_scan_iterate(struct ieee80211vap *,
 171                 ieee80211_scan_iter_func, void *);
 172 enum {
 173         IEEE80211_BPARSE_BADIELEN       = 0x01, /* ie len past end of frame */
 174         IEEE80211_BPARSE_RATES_INVALID  = 0x02, /* invalid RATES ie */
 175         IEEE80211_BPARSE_XRATES_INVALID = 0x04, /* invalid XRATES ie */
 176         IEEE80211_BPARSE_SSID_INVALID   = 0x08, /* invalid SSID ie */
 177         IEEE80211_BPARSE_CHAN_INVALID   = 0x10, /* invalid FH/DSPARMS chan */
 178         IEEE80211_BPARSE_OFFCHAN        = 0x20, /* DSPARMS chan != curchan */
 179         IEEE80211_BPARSE_BINTVAL_INVALID= 0x40, /* invalid beacon interval */
 180         IEEE80211_BPARSE_CSA_INVALID    = 0x80, /* invalid CSA ie */
 181 };
 182
 183 /*
 184  * Parameters supplied when adding/updating an entry in a
 185  * scan cache.  Pointer variables should be set to NULL
 186  * if no data is available.  Pointer references can be to
 187  * local data; any information that is saved will be copied.
 188  * All multi-byte values must be in host byte order.
 189  */
 190 struct ieee80211_scanparams {
 191         uint8_t         status;         /* bitmask of IEEE80211_BPARSE_* */
 192         uint8_t         chan;           /* channel # from FH/DSPARMS */
 193         uint8_t         bchan;          /* curchan's channel # */
 194         uint8_t         fhindex;
 195         uint16_t        fhdwell;        /* FHSS dwell interval */
 196         uint16_t        capinfo;        /* 802.11 capabilities */
 197         uint16_t        erp;            /* NB: 0x100 indicates ie present */
 198         uint16_t        bintval;
 199         uint8_t         timoff;
 200         uint8_t         *ies;           /* all captured ies */
 201         size_t          ies_len;        /* length of all captured ies */
 202         uint8_t         *tim;
 203         uint8_t         *tstamp;
 204         uint8_t         *country;
 205         uint8_t         *ssid;
 206         uint8_t         *rates;
 207         uint8_t         *xrates;
 208         uint8_t         *doth;
 209         uint8_t         *wpa;
 210         uint8_t         *rsn;
 211         uint8_t         *wme;
 212         uint8_t         *htcap;
 213         uint8_t         *htinfo;
 214         uint8_t         *ath;
 215         uint8_t         *tdma;
 216         uint8_t         *csa;
 217         uint8_t         *meshid;
 218         uint8_t         *meshconf;
 219         uint8_t         *spare[3];
 220 };
 221
 222 /*
 223  * Scan cache entry format used when exporting data from a policy
 224  * module; this data may be represented some other way internally.
 225  */
 226 struct ieee80211_scan_entry {
 227         uint8_t         se_macaddr[IEEE80211_ADDR_LEN];
 228         uint8_t         se_bssid[IEEE80211_ADDR_LEN];
 229         /* XXX can point inside se_ies */
 230         uint8_t         se_ssid[2+IEEE80211_NWID_LEN];
 231         uint8_t         se_rates[2+IEEE80211_RATE_MAXSIZE];
 232         uint8_t         se_xrates[2+IEEE80211_RATE_MAXSIZE];
 233         union {
 234                 uint8_t         data[8];
 235                 u_int64_t       tsf;
 236         } se_tstamp;                    /* from last rcv'd beacon */
 237         uint16_t        se_intval;      /* beacon interval (host byte order) */
 238         uint16_t        se_capinfo;     /* capabilities (host byte order) */
 239         struct ieee80211_channel *se_chan;/* channel where sta found */
 240         uint16_t        se_timoff;      /* byte offset to TIM ie */
 241         uint16_t        se_fhdwell;     /* FH only (host byte order) */
 242         uint8_t         se_fhindex;     /* FH only */
 243         uint8_t         se_dtimperiod;  /* DTIM period */
 244         uint16_t        se_erp;         /* ERP from beacon/probe resp */
 245         int8_t          se_rssi;        /* avg'd recv ssi */
 246         int8_t          se_noise;       /* noise floor */
 247         uint8_t         se_cc[2];       /* captured country code */
 248         uint8_t         se_meshid[2+IEEE80211_MESHID_LEN];
 249         struct ieee80211_ies se_ies;    /* captured ie's */
 250         u_int           se_age;         /* age of entry (0 on create) */
 251 };
 252 MALLOC_DECLARE(M_80211_SCAN);
 253
 254 /*
 255  * Template for an in-kernel scan policy module.
 256  * Modules register with the scanning code and are
 257  * typically loaded as needed.
 258  */
 259 struct ieee80211_scanner {
 260         const char *scan_name;          /* printable name */
 261         int     (*scan_attach)(struct ieee80211_scan_state *);
 262         int     (*scan_detach)(struct ieee80211_scan_state *);
 263         int     (*scan_start)(struct ieee80211_scan_state *,
 264                         struct ieee80211vap *);
 265         int     (*scan_restart)(struct ieee80211_scan_state *,
 266                         struct ieee80211vap *);
 267         int     (*scan_cancel)(struct ieee80211_scan_state *,
 268                         struct ieee80211vap *);
 269         int     (*scan_end)(struct ieee80211_scan_state *,
 270                         struct ieee80211vap *);
 271         int     (*scan_flush)(struct ieee80211_scan_state *);
 272         struct ieee80211_channel *(*scan_pickchan)(
 273                         struct ieee80211_scan_state *, int);
 274         /* add an entry to the cache */
 275         int     (*scan_add)(struct ieee80211_scan_state *,
 276                         const struct ieee80211_scanparams *,
 277                         const struct ieee80211_frame *,
 278                         int subtype, int rssi, int noise);
 279         /* age and/or purge entries in the cache */
 280         void    (*scan_age)(struct ieee80211_scan_state *);
 281         /* note that association failed for an entry */
 282         void    (*scan_assoc_fail)(struct ieee80211_scan_state *,
 283                         const uint8_t macaddr[IEEE80211_ADDR_LEN],
 284                         int reason);
 285         /* note that association succeed for an entry */
 286         void    (*scan_assoc_success)(struct ieee80211_scan_state *,
 287                         const uint8_t macaddr[IEEE80211_ADDR_LEN]);
 288         /* iterate over entries in the scan cache */
 289         void    (*scan_iterate)(struct ieee80211_scan_state *,
 290                         ieee80211_scan_iter_func *, void *);
 291         void    (*scan_spare0)(void);
 292         void    (*scan_spare1)(void);
 293         void    (*scan_spare2)(void);
 294         void    (*scan_spare4)(void);
 295 };
 296 void    ieee80211_scanner_register(enum ieee80211_opmode,
 297                 const struct ieee80211_scanner *);
 298 void    ieee80211_scanner_unregister(enum ieee80211_opmode,
 299                 const struct ieee80211_scanner *);
 300 void    ieee80211_scanner_unregister_all(const struct ieee80211_scanner *);
 301 const struct ieee80211_scanner *ieee80211_scanner_get(enum ieee80211_opmode);
 302 #endif /* _NET80211_IEEE80211_SCAN_H_ */