path: root/Documentation
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authorJohannes Berg <johannes@sipsolutions.net>2007-09-26 17:53:18 +0200
committerDavid S. Miller <davem@sunset.davemloft.net>2007-10-10 16:54:18 -0700
commit58d4185e36913d4fc94afa4b4daccb3c9aa01957 (patch)
tree77d2e8e423652f5bbf2e29e8c0b3e0aeb7858b9f /Documentation
parent[MAC80211]: remove ALG_NONE (diff)
[MAC80211]: improve radiotap injection
This improves radiotap injection by removing the shortcut over TX handlers that led to BUGS when injecting frames without setting a rate and also resulted in various other quirks. Now, TX handlers are run but some information that was present in the radiotap header is used instead of automatic settings. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Cc: Andy Green <andy@warmcat.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'Documentation')
1 files changed, 26 insertions, 6 deletions
diff --git a/Documentation/networking/mac80211-injection.txt b/Documentation/networking/mac80211-injection.txt
index 53ef7a06f49c..84906ef3ed6e 100644
--- a/Documentation/networking/mac80211-injection.txt
+++ b/Documentation/networking/mac80211-injection.txt
@@ -13,15 +13,35 @@ The radiotap format is discussed in
Despite 13 radiotap argument types are currently defined, most only make sense
-to appear on received packets. Currently three kinds of argument are used by
-the injection code, although it knows to skip any other arguments that are
-present (facilitating replay of captured radiotap headers directly):
+to appear on received packets. The following information is parsed from the
+radiotap headers and used to control injection:
- - IEEE80211_RADIOTAP_RATE - u8 arg in 500kbps units (0x02 --> 1Mbps)
- - IEEE80211_RADIOTAP_ANTENNA - u8 arg, 0x00 = ant1, 0x01 = ant2
+ rate in 500kbps units, automatic if invalid or not present
- - IEEE80211_RADIOTAP_DBM_TX_POWER - u8 arg, dBm
+ antenna to use, automatic if not present
+ transmit power in dBm, automatic if not present
+ IEEE80211_RADIOTAP_F_FCS: FCS will be removed and recalculated
+ IEEE80211_RADIOTAP_F_WEP: frame will be encrypted if key available
+ IEEE80211_RADIOTAP_F_FRAG: frame will be fragmented if longer than the
+ current fragmentation threshold. Note that
+ this flag is only reliable when software
+ fragmentation is enabled)
+The injection code can also skip all other currently defined radiotap fields
+facilitating replay of captured radiotap headers directly.
Here is an example valid radiotap header defining these three parameters