[Click] Why roofnet can not work on high rates

[Robert Sombrutzki]

Hello,
we had the same problem using ath9k, which is part of the Compat-wireless 
package (http://wireless.kernel.org/en/users/Download). We're using the 
version 2010-12-16 
(http://wireless.kernel.org/download/compat-wireless-2.6/compat-wireless-2010-12-16.tar.bz2) 
and same patches from openwrt (backfire). Using this driver, which is newer 
than your driver (Ubuntu), rate selection using the radiotab header doesn't 
work, since the driver ignores the rates. The function "static bool 
__ieee80211_parse_tx_radiotap(struct ieee80211_tx_data *tx,struct sk_buff 
*skb)" in net/mac80211/tx.c considers the radiotap flags and nothing else.
There is already a patch to solve this problem:
https://patchwork.kernel.org/patch/43026/

Best regards,
Robert

On Montag, 17. Januar 2011, 欧阳鑫 wrote:
> Hi, everyone.
>
>      I am running roofnet experiments on 2 Ubuntu hosts with 2.6.32-26
> kernel. Both are AR5416 cards with ath9k driver. All cards run in Monitor
> mode.
>
>      The problem is that hosts seems to be running under 1Mbps rate ONLY.
> Command "read srcr/es.bcast_stats" shows:
> 200 Read handler 'srcr/es.bcast_stats' OK
> DATA 363
> 5.167.1.211 00-25-86-A7-01-D3 seq 1295164746 period 30000 tau 300000 sent
> 12 last_rx 1.762133
> 5.167.1.211 00-25-86-A7-01-D3 [ 2 60 100 100 198 0 ]
> 5.167.1.211 00-25-86-A7-01-D3 [ 2 1500 100 100 197 0 ]
> 5.167.1.211 00-25-86-A7-01-D3 [ 4 1500 0 100 198 0 ]
> 5.167.1.211 00-25-86-A7-01-D3 [ 11 1500 0 100 196 0 ]
> 5.167.1.211 00-25-86-A7-01-D3 [ 22 1500 0 100 197 0 ]
>     I do not  know why fwd_rate with 2Mb/s, 5.5 Mb/s and 11 Mb/s are all
> 0s.
>
>     I forced the data rate to be 5.5Mbps by SetTXRate(11) on PC1, then ping
> PC1 on PC2, then I run tcpdump on PC2, the result is as follows:
> tcpdump -i wlan0 -n -e -xX
>
> 15:59:49.476661 5.5 Mb/s 63dBm tx power [0x00000010] DA:ff:ff:ff:ff:ff:ff
> SA:PC2-MAC  BSSID:00:00:00:00:00:00 LLC, dsap SNAP (0xaa) Individual, ssap
> SNAP (0xaa) Command, ctrl 0x03: oui Ethernet (0x000000), ethertype Unknown
> (0x0941): Unnumbered, ui, Flags [Command], length 1494
>         0x0000:  aaaa 0300 0000 0941 0200 87e4 3c00 0b00  .......A....<...
>         0x0010:  dc05 0000 05a7 01d3 0100 0000 75a5 324d  ............u.2M
>         0x0020:  3075 0000 e093 0400                      0u......
> 15:59:49.476661 1.0 Mb/s [0x0000000f] DA:ff:ff:ff:ff:ff:ff SA:PC2-MAC
> BSSID:00:00:00:00:00:00 LLC, dsap SNAP (0xaa) Individual, ssap SNAP (0xaa)
> Command, ctrl 0x03: oui Ethernet (0x000000), ethertype Unknown (0x0941):
> Unnumbered, ui, Flags [Command], length 1494
>         0x0000:  aaaa 0300 0000 0941 0200 87e4 3c00 0b00  .......A....<...
>         0x0010:  dc05 0000 05a7 01d3 0100 0000 75a5 324d  ............u.2M
>         0x0020:  3075 0000 e093 04                         0u.....
>
>  15:59:48.460612 5.5 Mb/s 63dBm tx power [0x00000010] DA:PC1-MAC SA:PC2-MAC
> BSSID:00:00:00:00:00:00 LLC, dsap SNAP (0xaa) Individual, ssap SNAP (0xaa)
> Command, ctrl 0x03: oui Ethernet (0x000000), ethertype Unknown (0x0943):
> Unnumbered, ui, Flags [Command], length 162
>         0x0000:  aaaa 0300 0000 0943 0b04 0101 0000 fc7b  .......C.......{
>         0x0010:  0000 0054 0000 0000 0000 0000 0000 0000 ...T............
>         0x0020:  0000 0000 0000 0000
> ........
> 15:59:48.460612 1.0 Mb/s [0x0000000f] DA:PC1-MAC  SA:PC2-MAC
> BSSID:00:00:00:00:00:00 LLC, dsap SNAP (0xaa) Individual, ssap SNAP (0xaa)
> Command, ctrl 0x03: oui Ethernet (0x000000), ethertype Unknown (0x0943):
> Unnumbered, ui, Flags [Command], length 162
>         0x0000:  aaaa 0300 0000 0943 0b04 0101 0000 fc7b
> .......C.......{
>         0x0010:  0000 0054 0000 0000 0000 0000 0000 0000
> ...T............
>         0x0020:  0000 0000 0000 00
> .......
>   It seemed that each packet was caught by tcpdump 2 times, and the 2
> copies share the same timestamp but different rates.
>
>   My second question is why each packet was caught with a rate of 5.5Mb/s
> first, and then with a rate of 1Mb/s.
>
>   The attachment is my configuration file: gen_config_roofnet.pl. I do not
> know if there is some error with the configuration file. Would you help me
> check for it?
>
>  Thank you very much!