FreeBSD/Linux Kernel Cross Reference
sys/net80211/ieee80211_scan.h

     /*-
      * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      *
      * Copyright (c) 2005-2009 Sam Leffler, Errno Consulting
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     *
     * $FreeBSD$
     */
    #ifndef _NET80211_IEEE80211_SCAN_H_
    #define _NET80211_IEEE80211_SCAN_H_
    
    /*
     * 802.11 scanning support.
     *
     * Scanning is the procedure by which a station locates a bss to join
     * (infrastructure/ibss mode), or a channel to use (when operating as
     * an ap or ibss master).  Scans are either "active" or "passive".  An
     * active scan causes one or more probe request frames to be sent on
     * visiting each channel.  A passive request causes each channel in the
     * scan set to be visited but no frames to be transmitted; the station
     * only listens for traffic.  Note that active scanning may still need
     * to listen for traffic before sending probe request frames depending
     * on regulatory constraints; the 802.11 layer handles this by generating
     * a callback when scanning on a ``passive channel'' when the
     * IEEE80211_FEXT_PROBECHAN flag is set.
     *
     * A scan operation involves constructing a set of channels to inspect
     * (the scan set), visiting each channel and collecting information
     * (e.g. what bss are present), and then analyzing the results to make
     * decisions like which bss to join.  This process needs to be as fast
     * as possible so we do things like intelligently construct scan sets
     * and dwell on a channel only as long as necessary.  The scan code also
     * maintains a cache of recent scan results and uses it to bypass scanning
     * whenever possible.  The scan cache is also used to enable roaming
     * between access points when operating in infrastructure mode.
     *
     * Scanning is handled with pluggable modules that implement "policy"
     * per-operating mode.  The core scanning support provides an
     * instrastructure to support these modules and exports a common api
     * to the rest of the 802.11 layer.  Policy modules decide what
     * channels to visit, what state to record to make decisions (e.g. ap
     * mode scanning for auto channel selection keeps significantly less
     * state than sta mode scanning for an ap to associate to), and selects
     * the final station/channel to return as the result of a scan.
     *
     * Scanning is done synchronously when initially bringing a vap to an
     * operational state and optionally in the background to maintain the
     * scan cache for doing roaming and rogue ap monitoring.  Scanning is
     * not tied to the 802.11 state machine that governs vaps though there
     * is linkage to the IEEE80211_SCAN state.  Only one vap at a time may
     * be scanning; this scheduling policy is handled in ieee80211_new_state
     * and is invisible to the scanning code.
    */
    #define IEEE80211_SCAN_MAX      IEEE80211_CHAN_MAX
    
    struct ieee80211_scanner;                       /* scan policy state */
    
    struct ieee80211_scan_ssid {
            int      len;                           /* length in bytes */
            uint8_t ssid[IEEE80211_NWID_LEN];       /* ssid contents */
    };
    #define IEEE80211_SCAN_MAX_SSID 1               /* max # ssid's to probe */
    
    /*
     * High-level implementation visible to ieee80211_scan.[ch].
     *
     * The default scanner (ieee80211_scan_sw.[ch]) implements a software
     * driven scanner.  Firmware driven scanning needs a different set of
     * behaviours.
     */
    struct ieee80211_scan_methods {
            void (*sc_attach)(struct ieee80211com *);
            void (*sc_detach)(struct ieee80211com *);
            void (*sc_vattach)(struct ieee80211vap *);
            void (*sc_vdetach)(struct ieee80211vap *);
            void (*sc_set_scan_duration)(struct ieee80211vap *, u_int);
            int (*sc_start_scan)(const struct ieee80211_scanner *,
                struct ieee80211vap *, int, u_int, u_int, u_int, u_int,
                const struct ieee80211_scan_ssid ssids[]);
           int (*sc_check_scan)(const struct ieee80211_scanner *,
               struct ieee80211vap *, int, u_int, u_int, u_int, u_int,
               const struct ieee80211_scan_ssid ssids[]);
           int (*sc_bg_scan)(const struct ieee80211_scanner *,
               struct ieee80211vap *, int);
           void (*sc_cancel_scan)(struct ieee80211vap *);
           void (*sc_cancel_anyscan)(struct ieee80211vap *);
           void (*sc_scan_next)(struct ieee80211vap *);
           void (*sc_scan_done)(struct ieee80211vap *);
           void (*sc_scan_probe_curchan)(struct ieee80211vap *, int);
           void (*sc_add_scan)(struct ieee80211vap *,
               struct ieee80211_channel *,
               const struct ieee80211_scanparams *,
               const struct ieee80211_frame *,
               int, int, int);
   };
   
   /*
    * Scan state visible to the 802.11 layer.  Scan parameters and
    * results are stored in this data structure.  The ieee80211_scan_state
    * structure is extended with space that is maintained private to
    * the core scanning support.  We allocate one instance and link it
    * to the ieee80211com structure; then share it between all associated
    * vaps.  We could allocate multiple of these, e.g. to hold multiple
    * scan results, but this is sufficient for current needs.
    */
   struct ieee80211_scan_state {
           struct ieee80211vap *ss_vap;
           struct ieee80211com *ss_ic;
           const struct ieee80211_scanner *ss_ops; /* policy hookup, see below */
           void            *ss_priv;               /* scanner private state */
           uint16_t        ss_flags;
   #define IEEE80211_SCAN_NOPICK   0x0001          /* scan only, no selection */
   #define IEEE80211_SCAN_ACTIVE   0x0002          /* active scan (probe req) */
   #define IEEE80211_SCAN_PICK1ST  0x0004          /* ``hey sailor'' mode */
   #define IEEE80211_SCAN_BGSCAN   0x0008          /* bg scan, exit ps at end */
   #define IEEE80211_SCAN_ONCE     0x0010          /* do one complete pass */
   #define IEEE80211_SCAN_NOBCAST  0x0020          /* no broadcast probe req */
   #define IEEE80211_SCAN_NOJOIN   0x0040          /* no auto-sequencing */
   #define IEEE80211_SCAN_GOTPICK  0x1000          /* got candidate, can stop */
           uint8_t         ss_nssid;               /* # ssid's to probe/match */
           struct ieee80211_scan_ssid ss_ssid[IEEE80211_SCAN_MAX_SSID];
                                                   /* ssid's to probe/match */
                                                   /* ordered channel set */
           struct ieee80211_channel *ss_chans[IEEE80211_SCAN_MAX];
           uint16_t        ss_next;                /* ix of next chan to scan */
           uint16_t        ss_last;                /* ix+1 of last chan to scan */
           unsigned long   ss_mindwell;            /* min dwell on channel */
           unsigned long   ss_maxdwell;            /* max dwell on channel */
   };
   
   /*
    * The upper 16 bits of the flags word is used to communicate
    * information to the scanning code that is NOT recorded in
    * ss_flags.  It might be better to split this stuff out into
    * a separate variable to avoid confusion.
    */
   #define IEEE80211_SCAN_FLUSH    0x00010000      /* flush candidate table */
   #define IEEE80211_SCAN_NOSSID   0x80000000      /* don't update ssid list */
   
   struct ieee80211com;
   void    ieee80211_scan_attach(struct ieee80211com *);
   void    ieee80211_scan_detach(struct ieee80211com *);
   void    ieee80211_scan_vattach(struct ieee80211vap *);
   void    ieee80211_scan_vdetach(struct ieee80211vap *);
   
   void    ieee80211_scan_dump_channels(const struct ieee80211_scan_state *);
   
   #define IEEE80211_SCAN_FOREVER  0x7fffffff
   int     ieee80211_start_scan(struct ieee80211vap *, int flags,
                   u_int duration, u_int mindwell, u_int maxdwell,
                   u_int nssid, const struct ieee80211_scan_ssid ssids[]);
   int     ieee80211_check_scan(struct ieee80211vap *, int flags,
                   u_int duration, u_int mindwell, u_int maxdwell,
                   u_int nssid, const struct ieee80211_scan_ssid ssids[]);
   int     ieee80211_check_scan_current(struct ieee80211vap *);
   int     ieee80211_bg_scan(struct ieee80211vap *, int);
   void    ieee80211_cancel_scan(struct ieee80211vap *);
   void    ieee80211_cancel_anyscan(struct ieee80211vap *);
   void    ieee80211_scan_next(struct ieee80211vap *);
   void    ieee80211_scan_done(struct ieee80211vap *);
   void    ieee80211_probe_curchan(struct ieee80211vap *, int);
   struct ieee80211_channel *ieee80211_scan_pickchannel(struct ieee80211com *, int);
   
   struct ieee80211_scanparams;
   void    ieee80211_add_scan(struct ieee80211vap *,
                   struct ieee80211_channel *,
                   const struct ieee80211_scanparams *,
                   const struct ieee80211_frame *,
                   int subtype, int rssi, int noise);
   void    ieee80211_scan_timeout(struct ieee80211com *);
   
   void    ieee80211_scan_assoc_success(struct ieee80211vap *,
                   const uint8_t mac[IEEE80211_ADDR_LEN]);
   enum {
           IEEE80211_SCAN_FAIL_TIMEOUT     = 1,    /* no response to mgmt frame */
           IEEE80211_SCAN_FAIL_STATUS      = 2     /* negative response to " " */
   };
   void    ieee80211_scan_assoc_fail(struct ieee80211vap *,
                   const uint8_t mac[IEEE80211_ADDR_LEN], int reason);
   void    ieee80211_scan_flush(struct ieee80211vap *);
   
   struct ieee80211_scan_entry;
   typedef void ieee80211_scan_iter_func(void *,
                   const struct ieee80211_scan_entry *);
   void    ieee80211_scan_iterate(struct ieee80211vap *,
                   ieee80211_scan_iter_func, void *);
   enum {
           IEEE80211_BPARSE_BADIELEN       = 0x01, /* ie len past end of frame */
           IEEE80211_BPARSE_RATES_INVALID  = 0x02, /* invalid RATES ie */
           IEEE80211_BPARSE_XRATES_INVALID = 0x04, /* invalid XRATES ie */
           IEEE80211_BPARSE_SSID_INVALID   = 0x08, /* invalid SSID ie */
           IEEE80211_BPARSE_CHAN_INVALID   = 0x10, /* invalid FH/DSPARMS chan */
           IEEE80211_BPARSE_OFFCHAN        = 0x20, /* DSPARMS chan != curchan */
           IEEE80211_BPARSE_BINTVAL_INVALID= 0x40, /* invalid beacon interval */
           IEEE80211_BPARSE_CSA_INVALID    = 0x80, /* invalid CSA ie */
           IEEE80211_BPARSE_MESHID_INVALID = 0x100, /* invalid Mesh ID ie */
   };
   
   /*
    * Parameters supplied when adding/updating an entry in a
    * scan cache.  Pointer variables should be set to NULL
    * if no data is available.  Pointer references can be to
    * local data; any information that is saved will be copied.
    * All multi-byte values must be in host byte order.
    */
   struct ieee80211_scanparams {
           uint32_t        status;         /* bitmask of IEEE80211_BPARSE_* */
           uint8_t         chan;           /* channel # from FH/DSPARMS */
           uint8_t         bchan;          /* curchan's channel # */
           uint8_t         fhindex;
           uint16_t        fhdwell;        /* FHSS dwell interval */
           uint16_t        capinfo;        /* 802.11 capabilities */
           uint16_t        erp;            /* NB: 0x100 indicates ie present */
           uint16_t        bintval;
           uint8_t         timoff;
           uint8_t         *ies;           /* all captured ies */
           size_t          ies_len;        /* length of all captured ies */
           uint8_t         *tim;
           uint8_t         *tstamp;
           uint8_t         *country;
           uint8_t         *ssid;
           uint8_t         *rates;
           uint8_t         *xrates;
           uint8_t         *doth;
           uint8_t         *wpa;
           uint8_t         *rsn;
           uint8_t         *wme;
           uint8_t         *htcap;
           uint8_t         *htinfo;
           uint8_t         *ath;
           uint8_t         *tdma;
           uint8_t         *csa;
           uint8_t         *quiet;
           uint8_t         *meshid;
           uint8_t         *meshconf;
           uint8_t         *vhtcap;
           uint8_t         *vhtopmode;
           uint8_t         *spare[1];
   };
   
   /*
    * Scan cache entry format used when exporting data from a policy
    * module; this data may be represented some other way internally.
    */
   struct ieee80211_scan_entry {
           uint8_t         se_macaddr[IEEE80211_ADDR_LEN];
           uint8_t         se_bssid[IEEE80211_ADDR_LEN];
           /* XXX can point inside se_ies */
           uint8_t         se_ssid[2+IEEE80211_NWID_LEN];
           uint8_t         se_rates[2+IEEE80211_RATE_MAXSIZE];
           uint8_t         se_xrates[2+IEEE80211_RATE_MAXSIZE];
           union {
                   uint8_t         data[8];
                   u_int64_t       tsf;
           } se_tstamp;                    /* from last rcv'd beacon */
           uint16_t        se_intval;      /* beacon interval (host byte order) */
           uint16_t        se_capinfo;     /* capabilities (host byte order) */
           struct ieee80211_channel *se_chan;/* channel where sta found */
           uint16_t        se_timoff;      /* byte offset to TIM ie */
           uint16_t        se_fhdwell;     /* FH only (host byte order) */
           uint8_t         se_fhindex;     /* FH only */
           uint8_t         se_dtimperiod;  /* DTIM period */
           uint16_t        se_erp;         /* ERP from beacon/probe resp */
           int8_t          se_rssi;        /* avg'd recv ssi */
           int8_t          se_noise;       /* noise floor */
           uint8_t         se_cc[2];       /* captured country code */
           uint8_t         se_meshid[2+IEEE80211_MESHID_LEN];
           struct ieee80211_ies se_ies;    /* captured ie's */
           u_int           se_age;         /* age of entry (0 on create) */
   };
   MALLOC_DECLARE(M_80211_SCAN);
   
   /*
    * Template for an in-kernel scan policy module.
    * Modules register with the scanning code and are
    * typically loaded as needed.
    */
   struct ieee80211_scanner {
           const char *scan_name;          /* printable name */
           int     (*scan_attach)(struct ieee80211_scan_state *);
           int     (*scan_detach)(struct ieee80211_scan_state *);
           int     (*scan_start)(struct ieee80211_scan_state *,
                           struct ieee80211vap *);
           int     (*scan_restart)(struct ieee80211_scan_state *,
                           struct ieee80211vap *);
           int     (*scan_cancel)(struct ieee80211_scan_state *,
                           struct ieee80211vap *);
           int     (*scan_end)(struct ieee80211_scan_state *,
                           struct ieee80211vap *);
           int     (*scan_flush)(struct ieee80211_scan_state *);
           struct ieee80211_channel *(*scan_pickchan)(
                           struct ieee80211_scan_state *, int);
           /* add an entry to the cache */
           int     (*scan_add)(struct ieee80211_scan_state *,
                           struct ieee80211_channel *,
                           const struct ieee80211_scanparams *,
                           const struct ieee80211_frame *,
                           int subtype, int rssi, int noise);
           /* age and/or purge entries in the cache */
           void    (*scan_age)(struct ieee80211_scan_state *);
           /* note that association failed for an entry */
           void    (*scan_assoc_fail)(struct ieee80211_scan_state *,
                           const uint8_t macaddr[IEEE80211_ADDR_LEN],
                           int reason);
           /* note that association succeed for an entry */
           void    (*scan_assoc_success)(struct ieee80211_scan_state *,
                           const uint8_t macaddr[IEEE80211_ADDR_LEN]);
           /* iterate over entries in the scan cache */
           void    (*scan_iterate)(struct ieee80211_scan_state *,
                           ieee80211_scan_iter_func *, void *);
           void    (*scan_spare0)(void);
           void    (*scan_spare1)(void);
           void    (*scan_spare2)(void);
           void    (*scan_spare4)(void);
   };
   void    ieee80211_scanner_register(enum ieee80211_opmode,
                   const struct ieee80211_scanner *);
   void    ieee80211_scanner_unregister(enum ieee80211_opmode,
                   const struct ieee80211_scanner *);
   void    ieee80211_scanner_unregister_all(const struct ieee80211_scanner *);
   const struct ieee80211_scanner *ieee80211_scanner_get(enum ieee80211_opmode);
   void    ieee80211_scan_update_locked(struct ieee80211vap *vap,
                   const struct ieee80211_scanner *scan);
   void    ieee80211_scan_copy_ssid(struct ieee80211vap *vap,
                   struct ieee80211_scan_state *ss,
                   int nssid, const struct ieee80211_scan_ssid ssids[]);
   void    ieee80211_scan_dump_probe_beacon(uint8_t subtype, int isnew,
                   const uint8_t mac[IEEE80211_ADDR_LEN],
                   const struct ieee80211_scanparams *sp, int rssi);
   void    ieee80211_scan_dump(struct ieee80211_scan_state *ss);
   
   #endif /* _NET80211_IEEE80211_SCAN_H_ */

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