ieee80211_scan.h

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/*-
 * 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 */
};
 
/*
 * 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 {
        uint8_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_ */