package/madwifi/patches/357-bgscan_thresh.patch

   1 Add an optional background scanning threshold triggered by low rssi
   2 (useful for passing updated scan results to the supplicant ahead of
   3 time, before losing connectivity entirely)
   4
   5 Signed-off-by: Felix Fietkau <nbd@openwrt.org>
   6
   7 --- a/net80211/ieee80211_ioctl.h
   8 +++ b/net80211/ieee80211_ioctl.h
   9 @@ -646,6 +646,7 @@
  10         IEEE80211_PARAM_MINRATE                 = 76,   /* Maximum rate (by table index) */
  11         IEEE80211_PARAM_PROTMODE_RSSI           = 77,   /* RSSI Threshold for enabling protection mode */
  12         IEEE80211_PARAM_PROTMODE_TIMEOUT        = 78,   /* Timeout for expiring protection mode */
  13 +       IEEE80211_PARAM_BGSCAN_THRESH           = 79,   /* bg scan rssi threshold */
  14  };
  15
  16  #define        SIOCG80211STATS                 (SIOCDEVPRIVATE+2)
  17 --- a/net80211/ieee80211_var.h
  18 +++ b/net80211/ieee80211_var.h
  19 @@ -92,6 +92,8 @@
  20  #define        IEEE80211_BGSCAN_IDLE_MIN       100     /* min idle time (ms) */
  21  #define        IEEE80211_BGSCAN_IDLE_DEFAULT   250     /* default idle time (ms) */
  22
  23 +#define IEEE80211_BGSCAN_TRIGGER_INTVL 20 /* min trigger interval for thresh based bgscan (secs) */
  24 +
  25  #define IEEE80211_COVERAGE_CLASS_MAX   31      /* max coverage class */
  26  #define IEEE80211_REGCLASSIDS_MAX      10      /* max regclass id list */
  27
  28 @@ -219,6 +221,10 @@
  29         u_int8_t iv_nickname[IEEE80211_NWID_LEN];
  30         u_int iv_bgscanidle;                            /* bg scan idle threshold */
  31         u_int iv_bgscanintvl;                           /* bg scan min interval */
  32 +       u_int iv_bgscanthr;                                     /* bg scan rssi threshold */
  33 +       u_int iv_bgscantrintvl;                         /* bg scan trigger interval */
  34 +       unsigned long iv_bgscanthr_next;                /* last trigger for bgscan */
  35 +       unsigned long iv_lastconnect;   /* time of last connect attempt */
  36         u_int iv_scanvalid;                             /* scan cache valid threshold */
  37         struct ieee80211_roam iv_roam;                  /* sta-mode roaming state */
  38
  39 @@ -608,6 +614,7 @@
  40  #define IEEE80211_FEXT_SWBMISS         0x00000400      /* CONF: use software beacon timer */
  41  #define IEEE80211_FEXT_DROPUNENC_EAPOL 0x00000800      /* CONF: drop unencrypted eapol frames */
  42  #define IEEE80211_FEXT_APPIE_UPDATE    0x00001000      /* STATE: beacon APP IE updated */
  43 +#define IEEE80211_FEXT_BGSCAN_THR      0x00002000      /* bgscan due to low rssi */
  44
  45  #define IEEE80211_COM_UAPSD_ENABLE(_ic)                ((_ic)->ic_flags_ext |= IEEE80211_FEXT_UAPSD)
  46  #define IEEE80211_COM_UAPSD_DISABLE(_ic)       ((_ic)->ic_flags_ext &= ~IEEE80211_FEXT_UAPSD)
  47 --- a/net80211/ieee80211_wireless.c
  48 +++ b/net80211/ieee80211_wireless.c
  49 @@ -2744,6 +2744,9 @@
  50                 else
  51                         retv = EINVAL;
  52                 break;
  53 +       case IEEE80211_PARAM_BGSCAN_THRESH:
  54 +               vap->iv_bgscanthr = value;
  55 +               break;
  56         case IEEE80211_PARAM_MCAST_RATE:
  57                 /* units are in KILObits per second */
  58                 if (value >= 256 && value <= 54000)
  59 @@ -3144,6 +3147,9 @@
  60         case IEEE80211_PARAM_BGSCAN_INTERVAL:
  61                 param[0] = vap->iv_bgscanintvl / HZ;    /* seconds */
  62                 break;
  63 +       case IEEE80211_PARAM_BGSCAN_THRESH:
  64 +               param[0] = vap->iv_bgscanthr;   /* rssi */
  65 +               break;
  66         case IEEE80211_PARAM_MCAST_RATE:
  67                 param[0] = vap->iv_mcast_rate;  /* seconds */
  68                 break;
  69 @@ -5666,6 +5672,10 @@
  70           IW_PRIV_TYPE_INT | IW_PRIV_SIZE_FIXED | 1, 0, "bgscanintvl" },
  71         { IEEE80211_PARAM_BGSCAN_INTERVAL,
  72           0, IW_PRIV_TYPE_INT | IW_PRIV_SIZE_FIXED | 1, "get_bgscanintvl" },
  73 +       { IEEE80211_PARAM_BGSCAN_THRESH,
  74 +         IW_PRIV_TYPE_INT | IW_PRIV_SIZE_FIXED | 1, 0, "bgscanthr" },
  75 +       { IEEE80211_PARAM_BGSCAN_THRESH,
  76 +         0, IW_PRIV_TYPE_INT | IW_PRIV_SIZE_FIXED | 1, "get_bgscanthr" },
  77         { IEEE80211_PARAM_MCAST_RATE,
  78           IW_PRIV_TYPE_INT | IW_PRIV_SIZE_FIXED | 1, 0, "mcast_rate" },
  79         { IEEE80211_PARAM_MCAST_RATE,
  80 --- a/net80211/ieee80211_input.c
  81 +++ b/net80211/ieee80211_input.c
  82 @@ -3013,8 +3013,10 @@
  83  {
  84         struct ieee80211com *ic = vap->iv_ic;
  85
  86 +       vap->iv_bgscantrintvl = (vap->iv_bgscantrintvl + 1) % 4;
  87         return ((ic->ic_flags_ext & IEEE80211_FEXT_BGSCAN) &&
  88 -               time_after(jiffies, ic->ic_lastdata + vap->iv_bgscanidle));
  89 +               (((ic->ic_flags_ext & IEEE80211_FEXT_BGSCAN_THR) && !vap->iv_bgscantrintvl) ||
  90 +                       time_after(jiffies, ic->ic_lastdata + vap->iv_bgscanidle)));
  91  }
  92
  93  static __inline int
  94 @@ -3258,6 +3260,25 @@
  95                         /* record tsf of last beacon */
  96                         memcpy(ni->ni_tstamp.data, scan.tstamp,
  97                                 sizeof(ni->ni_tstamp));
  98 +
  99 +                       /* When rssi is low, start doing bgscans more frequently to allow
 100 +                        * the supplicant to make a better switching decision */
 101 +                       if (!(ic->ic_flags & IEEE80211_F_SCAN) && (rssi < vap->iv_bgscanthr) &&
 102 +                                       (!vap->iv_bgscanthr_next ||
 103 +                                               !time_before(jiffies, vap->iv_bgscanthr_next)) &&
 104 +                                       (vap->iv_state == IEEE80211_S_RUN) &&
 105 +                                       time_after(jiffies, vap->iv_lastconnect +
 106 +                                               msecs_to_jiffies(IEEE80211_BGSCAN_INTVAL_MIN * 1000))) {
 107 +                               int ret;
 108 +
 109 +                               ic->ic_lastdata = 0;
 110 +                               ic->ic_lastscan = 0;
 111 +                               ic->ic_flags_ext |= IEEE80211_FEXT_BGSCAN_THR;
 112 +                               ret = ieee80211_bg_scan(vap);
 113 +                               if (ret)
 114 +                                       vap->iv_bgscanthr_next = jiffies + msecs_to_jiffies(IEEE80211_BGSCAN_TRIGGER_INTVL * 1000);
 115 +                       }
 116 +
 117                         if (ni->ni_intval != scan.bintval) {
 118                                 IEEE80211_NOTE(vap, IEEE80211_MSG_ASSOC, ni,
 119                                                 "beacon interval divergence: "
 120 --- a/net80211/ieee80211_scan.c
 121 +++ b/net80211/ieee80211_scan.c
 122 @@ -616,6 +616,7 @@
 123
 124                 /* clear bg scan NOPICK and mark cancel request */
 125                 ss->ss_flags &= ~IEEE80211_SCAN_NOPICK;
 126 +               ic->ic_flags_ext &= ~IEEE80211_FEXT_BGSCAN_THR;
 127                 SCAN_PRIVATE(ss)->ss_iflags |= ISCAN_CANCEL;
 128                 ss->ss_ops->scan_cancel(ss, vap);
 129                 /* force it to fire asap */
 130 @@ -782,7 +783,7 @@
 131                                 ieee80211_sta_pwrsave(vap, 0);
 132                                 if (ss->ss_next >= ss->ss_last) {
 133                                         ieee80211_notify_scan_done(vap);
 134 -                                       ic->ic_flags_ext &= ~IEEE80211_FEXT_BGSCAN;
 135 +                                       ic->ic_flags_ext &= ~(IEEE80211_FEXT_BGSCAN|IEEE80211_FEXT_BGSCAN_THR);
 136                                 }
 137                         }
 138                         SCAN_PRIVATE(ss)->ss_iflags &= ~ISCAN_CANCEL;
 139 --- a/net80211/ieee80211_proto.c
 140 +++ b/net80211/ieee80211_proto.c
 141 @@ -1450,6 +1450,7 @@
 142                 }
 143                 break;
 144         case IEEE80211_S_AUTH:
 145 +               vap->iv_lastconnect = jiffies;
 146                 /* auth frames are possible between IBSS nodes,
 147                  * see 802.11-1999, chapter 5.7.6 */
 148                 KASSERT(vap->iv_opmode == IEEE80211_M_STA ||
 149 --- a/net80211/ieee80211_output.c
 150 +++ b/net80211/ieee80211_output.c
 151 @@ -238,7 +238,8 @@
 152         }
 153
 154         /* Cancel any running BG scan */
 155 -       ieee80211_cancel_scan(vap);
 156 +       if (!(ic->ic_flags_ext & IEEE80211_FEXT_BGSCAN_THR) && (vap->iv_state == IEEE80211_S_RUN))
 157 +               ieee80211_cancel_scan(vap);
 158
 159         /*
 160          * Find the node for the destination so we can do