/share/man/man9/ieee80211_regdomain.9

https://bitbucket.org/freebsd/freebsd-head/ · Unknown · 143 lines · 143 code · 0 blank · 0 comment · 0 complexity · 52cda53a798de6251d170b2e76010e2a MD5 · raw file

  1. .\"
  2. .\" Copyright (c) 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 AND CONTRIBUTORS ``AS IS'' AND
  15. .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16. .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17. .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18. .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19. .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20. .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21. .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22. .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23. .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24. .\" SUCH DAMAGE.
  25. .\"
  26. .\" $FreeBSD$
  27. .\"
  28. .Dd August 4, 2009
  29. .Dt IEEE80211_REGDOMAIN 9
  30. .Os
  31. .Sh NAME
  32. .Nm ieee80211_regdomain
  33. .Nd 802.11 regulatory support
  34. .Sh SYNOPSIS
  35. .In net80211/ieee80211_var.h
  36. .In net80211/ieee80211_regdomain.h
  37. .Pp
  38. .Ft int
  39. .Fo ieee80211_init_channels
  40. .Fa "struct ieee80211com *"
  41. .Fa "const struct ieee80211_regdomain *"
  42. .Fa "const uint8_t bands[]"
  43. .Fc
  44. .\"
  45. .Ft void
  46. .Fo ieee80211_sort_channels
  47. .Fa "struct ieee80211_channel *"
  48. .Fa "int nchans"
  49. .Fc
  50. .\"
  51. .Ft "struct ieee80211_appie *"
  52. .Fn ieee80211_alloc_countryie "struct ieee80211com *"
  53. .Sh DESCRIPTION
  54. The
  55. .Nm net80211
  56. software layer provides a support framework for drivers that includes
  57. comprehensive regulatory support.
  58. .Nm net80211
  59. provides mechanisms that enforce
  60. .Em "regulatory policy"
  61. by privileged user applications.
  62. .Pp
  63. Drivers define a device's capabilities and can
  64. intercept and control regulatory changes requested through
  65. .Nm net80211 .
  66. The initial regulatory state, including the channel list, must be
  67. filled in by the driver before calling
  68. .Fn ieee80211_ifattach .
  69. The channel list should reflect the set of channels the device is
  70. .Em calibrated
  71. for use on.
  72. This list may also be requested later through the
  73. .Vt ic_getradiocaps
  74. method in the
  75. .Vt ieee80211com
  76. structure.
  77. The
  78. .Fn ieee80211_init_channels
  79. function is provided as a rudimentary fallback for drivers that do not
  80. (or cannot) fill in a proper channel list.
  81. Default regulatory state is supplied such as the regulatory SKU,
  82. ISO country code, location (e.g. indoor, outdoor), and a set of
  83. frequency bands the device is capable of operating on.
  84. .Nm net80211
  85. populates the channel table in
  86. .Vt ic_channels
  87. with a default set of channels and capabilities.
  88. Note this mechanism should be used with care as any mismatch between
  89. the channel list created and the device's capabilities can result
  90. in runtime errors (e.g. a request to operate on a channel the device
  91. does not support).
  92. The SKU and country information are used for generating 802.11h protocol
  93. elements and related operation such as for 802.11d; mis-setup by a
  94. driver is not fatal, only potentially confusing.
  95. .Pp
  96. Devices that do not have a fixed/default regulatory state can set
  97. the regulatory SKU to
  98. .Dv SKU_DEBUG
  99. and country code to
  100. .Dv CTRY_DEFAULT
  101. and leave proper setup to user applications.
  102. If default settings are known they can be installed and/or an event
  103. can be dispatched to user space using
  104. .Fn ieee80211_notify_country
  105. so that
  106. .Xr devd 8
  107. will do the appropriate setup work at system boot (or device insertion).
  108. .Pp
  109. The channel table is sorted to optimize lookups using the
  110. .Fn ieee80211_sort_channels
  111. routine.
  112. This should be done whenever the channel table contents are modified.
  113. .Pp
  114. The
  115. .Fn ieee80211_alloc_countryie
  116. function allocates an information element as specified by 802.11h.
  117. Because this is expensive to generate it is cached in
  118. .Vt ic_countryie
  119. and generated only when regulatory state changes.
  120. Drivers that call
  121. .Fn ieee80211_alloc_countryie
  122. directly should not help with this caching; doing so may confuse the
  123. .Nm net80211
  124. layer.
  125. .Sh DRIVER REGULATORY CONTROL
  126. Drivers can control regulatory change requests by overriding the
  127. .Vt ic_setregdomain
  128. method that checks change requests.
  129. While drivers can reject any request that does not meet its requirements
  130. it is recommended that one be lenient in what is accepted and, whenever
  131. possible, instead of rejecting a request, alter it to be correct.
  132. For example, if the transmit power cap for a channel is too high the
  133. driver can either reject the request or (better) reduce the cap to be
  134. compliant.
  135. Requests that include unacceptable channels should cause the request
  136. to be rejected as otherwise a mismatch may be created between application
  137. state and the state managed by
  138. .Nm net80211 .
  139. The exact rules by which to operate are still being codified.
  140. .Sh SEE ALSO
  141. .Xr regdomain 5 ,
  142. .Xr ifconfig 8 ,
  143. .Xr ieee80211 9