1 | #include <machine/rtems-bsd-kernel-space.h> |
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2 | |
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3 | /*- |
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4 | * Copyright (c) 2007-2008 Sam Leffler, Errno Consulting |
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5 | * All rights reserved. |
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6 | * |
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7 | * Redistribution and use in source and binary forms, with or without |
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8 | * modification, are permitted provided that the following conditions |
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9 | * are met: |
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10 | * 1. Redistributions of source code must retain the above copyright |
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11 | * notice, this list of conditions and the following disclaimer. |
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12 | * 2. Redistributions in binary form must reproduce the above copyright |
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13 | * notice, this list of conditions and the following disclaimer in the |
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14 | * documentation and/or other materials provided with the distribution. |
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15 | * |
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16 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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17 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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18 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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19 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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20 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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21 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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22 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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23 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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24 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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25 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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26 | */ |
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27 | |
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28 | #include <sys/cdefs.h> |
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29 | #ifdef __FreeBSD__ |
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30 | __FBSDID("$FreeBSD$"); |
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31 | #endif |
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32 | |
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33 | /* |
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34 | * IEEE 802.11 DFS/Radar support. |
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35 | */ |
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36 | #include <rtems/bsd/local/opt_inet.h> |
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37 | #include <rtems/bsd/local/opt_wlan.h> |
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38 | |
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39 | #include <rtems/bsd/sys/param.h> |
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40 | #include <sys/systm.h> |
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41 | #include <sys/mbuf.h> |
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42 | #include <sys/malloc.h> |
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43 | #include <sys/kernel.h> |
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44 | |
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45 | #include <sys/socket.h> |
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46 | #include <sys/sockio.h> |
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47 | #include <sys/endian.h> |
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48 | #include <rtems/bsd/sys/errno.h> |
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49 | #include <sys/proc.h> |
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50 | #include <sys/sysctl.h> |
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51 | |
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52 | #include <net/if.h> |
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53 | #include <net/if_media.h> |
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54 | |
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55 | #include <net80211/ieee80211_var.h> |
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56 | |
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57 | static MALLOC_DEFINE(M_80211_DFS, "80211dfs", "802.11 DFS state"); |
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58 | |
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59 | static int ieee80211_nol_timeout = 30*60; /* 30 minutes */ |
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60 | SYSCTL_INT(_net_wlan, OID_AUTO, nol_timeout, CTLFLAG_RW, |
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61 | &ieee80211_nol_timeout, 0, "NOL timeout (secs)"); |
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62 | #define NOL_TIMEOUT msecs_to_ticks(ieee80211_nol_timeout*1000) |
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63 | |
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64 | static int ieee80211_cac_timeout = 60; /* 60 seconds */ |
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65 | SYSCTL_INT(_net_wlan, OID_AUTO, cac_timeout, CTLFLAG_RW, |
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66 | &ieee80211_cac_timeout, 0, "CAC timeout (secs)"); |
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67 | #define CAC_TIMEOUT msecs_to_ticks(ieee80211_cac_timeout*1000) |
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68 | |
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69 | void |
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70 | ieee80211_dfs_attach(struct ieee80211com *ic) |
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71 | { |
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72 | struct ieee80211_dfs_state *dfs = &ic->ic_dfs; |
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73 | |
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74 | callout_init_mtx(&dfs->nol_timer, IEEE80211_LOCK_OBJ(ic), 0); |
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75 | callout_init_mtx(&dfs->cac_timer, IEEE80211_LOCK_OBJ(ic), 0); |
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76 | } |
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77 | |
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78 | void |
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79 | ieee80211_dfs_detach(struct ieee80211com *ic) |
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80 | { |
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81 | /* NB: we assume no locking is needed */ |
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82 | ieee80211_dfs_reset(ic); |
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83 | } |
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84 | |
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85 | void |
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86 | ieee80211_dfs_reset(struct ieee80211com *ic) |
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87 | { |
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88 | struct ieee80211_dfs_state *dfs = &ic->ic_dfs; |
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89 | int i; |
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90 | |
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91 | /* NB: we assume no locking is needed */ |
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92 | /* NB: cac_timer should be cleared by the state machine */ |
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93 | callout_drain(&dfs->nol_timer); |
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94 | for (i = 0; i < ic->ic_nchans; i++) |
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95 | ic->ic_channels[i].ic_state = 0; |
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96 | dfs->lastchan = NULL; |
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97 | } |
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98 | |
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99 | static void |
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100 | cac_timeout(void *arg) |
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101 | { |
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102 | struct ieee80211vap *vap = arg; |
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103 | struct ieee80211com *ic = vap->iv_ic; |
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104 | struct ieee80211_dfs_state *dfs = &ic->ic_dfs; |
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105 | int i; |
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106 | |
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107 | IEEE80211_LOCK_ASSERT(ic); |
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108 | |
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109 | if (vap->iv_state != IEEE80211_S_CAC) /* NB: just in case */ |
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110 | return; |
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111 | /* |
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112 | * When radar is detected during a CAC we are woken |
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113 | * up prematurely to switch to a new channel. |
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114 | * Check the channel to decide how to act. |
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115 | */ |
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116 | if (IEEE80211_IS_CHAN_RADAR(ic->ic_curchan)) { |
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117 | ieee80211_notify_cac(ic, ic->ic_curchan, |
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118 | IEEE80211_NOTIFY_CAC_RADAR); |
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119 | |
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120 | if_printf(vap->iv_ifp, |
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121 | "CAC timer on channel %u (%u MHz) stopped due to radar\n", |
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122 | ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq); |
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123 | |
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124 | /* XXX clobbers any existing desired channel */ |
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125 | /* NB: dfs->newchan may be NULL, that's ok */ |
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126 | vap->iv_des_chan = dfs->newchan; |
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127 | /* XXX recursive lock need ieee80211_new_state_locked */ |
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128 | ieee80211_new_state(vap, IEEE80211_S_SCAN, 0); |
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129 | } else { |
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130 | if_printf(vap->iv_ifp, |
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131 | "CAC timer on channel %u (%u MHz) expired; " |
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132 | "no radar detected\n", |
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133 | ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq); |
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134 | /* |
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135 | * Mark all channels with the current frequency |
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136 | * as having completed CAC; this keeps us from |
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137 | * doing it again until we change channels. |
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138 | */ |
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139 | for (i = 0; i < ic->ic_nchans; i++) { |
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140 | struct ieee80211_channel *c = &ic->ic_channels[i]; |
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141 | if (c->ic_freq == ic->ic_curchan->ic_freq) |
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142 | c->ic_state |= IEEE80211_CHANSTATE_CACDONE; |
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143 | } |
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144 | ieee80211_notify_cac(ic, ic->ic_curchan, |
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145 | IEEE80211_NOTIFY_CAC_EXPIRE); |
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146 | ieee80211_cac_completeswitch(vap); |
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147 | } |
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148 | } |
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149 | |
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150 | /* |
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151 | * Initiate the CAC timer. The driver is responsible |
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152 | * for setting up the hardware to scan for radar on the |
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153 | * channnel, we just handle timing things out. |
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154 | */ |
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155 | void |
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156 | ieee80211_dfs_cac_start(struct ieee80211vap *vap) |
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157 | { |
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158 | struct ieee80211com *ic = vap->iv_ic; |
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159 | struct ieee80211_dfs_state *dfs = &ic->ic_dfs; |
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160 | |
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161 | IEEE80211_LOCK_ASSERT(ic); |
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162 | |
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163 | callout_reset(&dfs->cac_timer, CAC_TIMEOUT, cac_timeout, vap); |
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164 | if_printf(vap->iv_ifp, "start %d second CAC timer on channel %u (%u MHz)\n", |
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165 | ticks_to_secs(CAC_TIMEOUT), |
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166 | ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq); |
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167 | ieee80211_notify_cac(ic, ic->ic_curchan, IEEE80211_NOTIFY_CAC_START); |
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168 | } |
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169 | |
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170 | /* |
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171 | * Clear the CAC timer. |
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172 | */ |
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173 | void |
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174 | ieee80211_dfs_cac_stop(struct ieee80211vap *vap) |
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175 | { |
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176 | struct ieee80211com *ic = vap->iv_ic; |
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177 | struct ieee80211_dfs_state *dfs = &ic->ic_dfs; |
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178 | |
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179 | IEEE80211_LOCK_ASSERT(ic); |
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180 | |
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181 | /* NB: racey but not important */ |
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182 | if (callout_pending(&dfs->cac_timer)) { |
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183 | if_printf(vap->iv_ifp, "stop CAC timer on channel %u (%u MHz)\n", |
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184 | ic->ic_curchan->ic_ieee, ic->ic_curchan->ic_freq); |
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185 | ieee80211_notify_cac(ic, ic->ic_curchan, |
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186 | IEEE80211_NOTIFY_CAC_STOP); |
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187 | } |
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188 | callout_stop(&dfs->cac_timer); |
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189 | } |
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190 | |
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191 | void |
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192 | ieee80211_dfs_cac_clear(struct ieee80211com *ic, |
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193 | const struct ieee80211_channel *chan) |
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194 | { |
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195 | int i; |
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196 | |
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197 | for (i = 0; i < ic->ic_nchans; i++) { |
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198 | struct ieee80211_channel *c = &ic->ic_channels[i]; |
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199 | if (c->ic_freq == chan->ic_freq) |
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200 | c->ic_state &= ~IEEE80211_CHANSTATE_CACDONE; |
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201 | } |
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202 | } |
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203 | |
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204 | static void |
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205 | dfs_timeout(void *arg) |
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206 | { |
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207 | struct ieee80211com *ic = arg; |
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208 | struct ieee80211_dfs_state *dfs = &ic->ic_dfs; |
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209 | struct ieee80211_channel *c; |
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210 | int i, oldest, now; |
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211 | |
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212 | IEEE80211_LOCK_ASSERT(ic); |
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213 | |
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214 | now = oldest = ticks; |
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215 | for (i = 0; i < ic->ic_nchans; i++) { |
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216 | c = &ic->ic_channels[i]; |
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217 | if (IEEE80211_IS_CHAN_RADAR(c)) { |
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218 | if (time_after_eq(now, dfs->nol_event[i]+NOL_TIMEOUT)) { |
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219 | c->ic_state &= ~IEEE80211_CHANSTATE_RADAR; |
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220 | if (c->ic_state & IEEE80211_CHANSTATE_NORADAR) { |
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221 | /* |
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222 | * NB: do this here so we get only one |
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223 | * msg instead of one for every channel |
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224 | * table entry. |
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225 | */ |
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226 | if_printf(ic->ic_ifp, "radar on channel" |
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227 | " %u (%u MHz) cleared after timeout\n", |
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228 | c->ic_ieee, c->ic_freq); |
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229 | /* notify user space */ |
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230 | c->ic_state &= |
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231 | ~IEEE80211_CHANSTATE_NORADAR; |
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232 | ieee80211_notify_radar(ic, c); |
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233 | } |
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234 | } else if (dfs->nol_event[i] < oldest) |
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235 | oldest = dfs->nol_event[i]; |
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236 | } |
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237 | } |
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238 | if (oldest != now) { |
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239 | /* arrange to process next channel up for a status change */ |
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240 | callout_schedule(&dfs->nol_timer, oldest + NOL_TIMEOUT - now); |
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241 | } |
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242 | } |
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243 | |
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244 | static void |
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245 | announce_radar(struct ifnet *ifp, const struct ieee80211_channel *curchan, |
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246 | const struct ieee80211_channel *newchan) |
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247 | { |
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248 | if (newchan == NULL) |
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249 | if_printf(ifp, "radar detected on channel %u (%u MHz)\n", |
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250 | curchan->ic_ieee, curchan->ic_freq); |
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251 | else |
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252 | if_printf(ifp, "radar detected on channel %u (%u MHz), " |
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253 | "moving to channel %u (%u MHz)\n", |
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254 | curchan->ic_ieee, curchan->ic_freq, |
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255 | newchan->ic_ieee, newchan->ic_freq); |
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256 | } |
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257 | |
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258 | /* |
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259 | * Handle a radar detection event on a channel. The channel is |
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260 | * added to the NOL list and we record the time of the event. |
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261 | * Entries are aged out after NOL_TIMEOUT. If radar was |
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262 | * detected while doing CAC we force a state/channel change. |
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263 | * Otherwise radar triggers a channel switch using the CSA |
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264 | * mechanism (when the channel is the bss channel). |
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265 | */ |
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266 | void |
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267 | ieee80211_dfs_notify_radar(struct ieee80211com *ic, struct ieee80211_channel *chan) |
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268 | { |
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269 | struct ieee80211_dfs_state *dfs = &ic->ic_dfs; |
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270 | int i, now; |
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271 | |
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272 | IEEE80211_LOCK_ASSERT(ic); |
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273 | |
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274 | /* |
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275 | * Mark all entries with this frequency. Notify user |
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276 | * space and arrange for notification when the radar |
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277 | * indication is cleared. Then kick the NOL processing |
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278 | * thread if not already running. |
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279 | */ |
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280 | now = ticks; |
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281 | for (i = 0; i < ic->ic_nchans; i++) { |
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282 | struct ieee80211_channel *c = &ic->ic_channels[i]; |
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283 | if (c->ic_freq == chan->ic_freq) { |
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284 | c->ic_state &= ~IEEE80211_CHANSTATE_CACDONE; |
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285 | c->ic_state |= IEEE80211_CHANSTATE_RADAR; |
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286 | dfs->nol_event[i] = now; |
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287 | } |
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288 | } |
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289 | ieee80211_notify_radar(ic, chan); |
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290 | chan->ic_state |= IEEE80211_CHANSTATE_NORADAR; |
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291 | if (!callout_pending(&dfs->nol_timer)) |
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292 | callout_reset(&dfs->nol_timer, NOL_TIMEOUT, dfs_timeout, ic); |
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293 | |
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294 | /* |
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295 | * If radar is detected on the bss channel while |
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296 | * doing CAC; force a state change by scheduling the |
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297 | * callout to be dispatched asap. Otherwise, if this |
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298 | * event is for the bss channel then we must quiet |
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299 | * traffic and schedule a channel switch. |
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300 | * |
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301 | * Note this allows us to receive notification about |
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302 | * channels other than the bss channel; not sure |
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303 | * that can/will happen but it's simple to support. |
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304 | */ |
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305 | if (chan == ic->ic_bsschan) { |
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306 | /* XXX need a way to defer to user app */ |
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307 | dfs->newchan = ieee80211_dfs_pickchannel(ic); |
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308 | |
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309 | announce_radar(ic->ic_ifp, chan, dfs->newchan); |
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310 | |
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311 | if (callout_pending(&dfs->cac_timer)) |
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312 | callout_schedule(&dfs->cac_timer, 0); |
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313 | else if (dfs->newchan != NULL) { |
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314 | /* XXX mode 1, switch count 2 */ |
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315 | /* XXX calculate switch count based on max |
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316 | switch time and beacon interval? */ |
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317 | ieee80211_csa_startswitch(ic, dfs->newchan, 1, 2); |
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318 | } else { |
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319 | /* |
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320 | * Spec says to stop all transmissions and |
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321 | * wait on the current channel for an entry |
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322 | * on the NOL to expire. |
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323 | */ |
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324 | /*XXX*/ |
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325 | if_printf(ic->ic_ifp, "%s: No free channels; waiting for entry " |
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326 | "on NOL to expire\n", __func__); |
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327 | } |
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328 | } else { |
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329 | /* |
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330 | * Issue rate-limited console msgs. |
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331 | */ |
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332 | if (dfs->lastchan != chan) { |
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333 | dfs->lastchan = chan; |
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334 | dfs->cureps = 0; |
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335 | announce_radar(ic->ic_ifp, chan, NULL); |
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336 | } else if (ppsratecheck(&dfs->lastevent, &dfs->cureps, 1)) { |
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337 | announce_radar(ic->ic_ifp, chan, NULL); |
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338 | } |
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339 | } |
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340 | } |
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341 | |
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342 | struct ieee80211_channel * |
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343 | ieee80211_dfs_pickchannel(struct ieee80211com *ic) |
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344 | { |
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345 | struct ieee80211_channel *c; |
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346 | int i, flags; |
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347 | uint16_t v; |
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348 | |
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349 | /* |
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350 | * Consult the scan cache first. |
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351 | */ |
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352 | flags = ic->ic_curchan->ic_flags & IEEE80211_CHAN_ALL; |
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353 | /* |
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354 | * XXX if curchan is HT this will never find a channel |
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355 | * XXX 'cuz we scan only legacy channels |
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356 | */ |
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357 | c = ieee80211_scan_pickchannel(ic, flags); |
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358 | if (c != NULL) |
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359 | return c; |
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360 | /* |
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361 | * No channel found in scan cache; select a compatible |
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362 | * one at random (skipping channels where radar has |
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363 | * been detected). |
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364 | */ |
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365 | get_random_bytes(&v, sizeof(v)); |
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366 | v %= ic->ic_nchans; |
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367 | for (i = v; i < ic->ic_nchans; i++) { |
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368 | c = &ic->ic_channels[i]; |
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369 | if (!IEEE80211_IS_CHAN_RADAR(c) && |
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370 | (c->ic_flags & flags) == flags) |
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371 | return c; |
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372 | } |
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373 | for (i = 0; i < v; i++) { |
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374 | c = &ic->ic_channels[i]; |
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375 | if (!IEEE80211_IS_CHAN_RADAR(c) && |
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376 | (c->ic_flags & flags) == flags) |
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377 | return c; |
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378 | } |
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379 | if_printf(ic->ic_ifp, "HELP, no channel located to switch to!\n"); |
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380 | return NULL; |
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381 | } |
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