A-MSDU reception not working?
Janusz Dziedzic
janusz.dziedzic at tieto.com
Tue Jul 8 00:02:01 PDT 2014
On 8 July 2014 08:50, Janusz Dziedzic <janusz.dziedzic at tieto.com> wrote:
> On 8 July 2014 08:43, Denton Gentry <denton.gentry at gmail.com> wrote:
>> I think I know what is happening now, though I've no idea why. The
>> throughput is low because we have many TCP retransmissions. We have
>> retransmissions because the TCP checksum is wrong on a number of
>> frames, and I do find data corruption in the payload so the checksum
>> definitely should be wrong. All of the corrupted frames were
>> originally one of the subframes in an A-MSDU packet.
>>
>> An example follows at the end of this message, as dissected by
>> Wireshark. iperf sends a very regular data pattern of "0123456789..."
>> over and over. Note how in subframe #2 offset 0x1e0 the bytes "32 33
>> 34" have been replaced by "72 36 35"
>>
>> 01e0 32 33 34 35 36 37 38 39 30 31 72 36 35 35 36 37 2345678901r65567
>>
>> I added printks at the bottom of ath10k_htt_rx_amsdu immediately
>> before the call to ath10k_process_rx. I found this same packet, and we
>> see the "72 36 35" corruption in the printk. So I think it happened in
>> ath10k_process_rx or before, not anything weird after passing it up to
>> mac80211.
>>
>> [ 101.863712] ath10k: 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30
>> [ 101.863727] ath10k: 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36
>> [ 101.863742] ath10k: 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32
>> [ 101.863757] ath10k: 33 34 35 36 37 38 39 30 31 72 36 35 35 36 37 38
>> [ 101.863773] ath10k: 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34
>> [ 101.863788] ath10k: 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30
>> [ 101.863803] ath10k: 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36
>>
>>
>> I've found a number of examples of similar corruption, always with
>> between one and four bytes replaced.
>>
>> 35363738 -> e52c6e07
>> 3435 -> b43f
>> 3839 -> c238
>> 31 -> 7f
>> 3435 -> 7436
>> 30 -> 50
>> 3233 -> bc37
>>
> Seems this could be because of:
>
> + /* cfg80211 expect this padding */
> + padding = (4 - (skb->len + sizeof(subframe_hdr))) & 0x3;
> + skb_put(skb, padding);
>
BTW, when AP (ath10k) send TCP ACK - are this packets also AMSDU?
I see in my case AP can send 3 x A-MSDU (with total size 304 bytes)
small frames aggregated. Maybe your HW have problems with that.
As I remember correctly someone some time ago report problems with
MacBook pro retina but I am not sure this is the same, while no one
tests the fix.
>>
>> The packet described above, dissected by Wireshark:
>>
>> No. Time Source Destination
>> Protocol Length Info
>> 2235 18.953349 192.168.144.79 192.168.144.13 TCP
>> 3112 52697 > 5001 [ACK] Seq=1391553 Ack=1 Win=131760 [TCP CHECKSUM
>> INCORRECT] Len=1448 TSval=1298580657 TSecr=4294947481
>>
>> Frame 2235: 3112 bytes on wire (24896 bits), 3112 bytes captured (24896 bits)
>> Encapsulation type: IEEE 802.11 plus radiotap radio header (23)
>> Arrival Time: Jul 7, 2014 23:03:37.763365000 PDT
>> [Time shift for this packet: 0.000000000 seconds]
>> Epoch Time: 1404799417.763365000 seconds
>> [Time delta from previous captured frame: 0.003476000 seconds]
>> [Time delta from previous displayed frame: 0.515641000 seconds]
>> [Time since reference or first frame: 18.953349000 seconds]
>> Frame Number: 2235
>> Frame Length: 3112 bytes (24896 bits)
>> Capture Length: 3112 bytes (24896 bits)
>> [Frame is marked: False]
>> [Frame is ignored: False]
>> [Protocols in frame: radiotap:wlan:llc:ip:tcp:data:llc:ip:tcp:data]
>> [Coloring Rule Name: TCP]
>> [Coloring Rule String: tcp]
>> Radiotap Header v0, Length 38
>> Header revision: 0
>> Header pad: 0
>> Header length: 38
>> Present flags
>> .... .... .... .... .... .... .... ...1 = TSFT: True
>> .... .... .... .... .... .... .... ..1. = Flags: True
>> .... .... .... .... .... .... .... .0.. = Rate: False
>> .... .... .... .... .... .... .... 1... = Channel: True
>> .... .... .... .... .... .... ...0 .... = FHSS: False
>> .... .... .... .... .... .... ..1. .... = dBm Antenna Signal: True
>> .... .... .... .... .... .... .0.. .... = dBm Antenna Noise: False
>> .... .... .... .... .... .... 0... .... = Lock Quality: False
>> .... .... .... .... .... ...0 .... .... = TX Attenuation: False
>> .... .... .... .... .... ..0. .... .... = dB TX Attenuation: False
>> .... .... .... .... .... .0.. .... .... = dBm TX Power: False
>> .... .... .... .... .... 1... .... .... = Antenna: True
>> .... .... .... .... ...0 .... .... .... = dB Antenna Signal: False
>> .... .... .... .... ..0. .... .... .... = dB Antenna Noise: False
>> .... .... .... .... .1.. .... .... .... = RX flags: True
>> .... .... .... .0.. .... .... .... .... = Channel+: False
>> .... .... .... 0... .... .... .... .... = HT information: False
>> .... .... ...0 .... .... .... .... .... = A-MPDU Status: False
>> .... .... ..1. .... .... .... .... .... = VHT information: True
>> ...0 0000 00.. .... .... .... .... .... = Reserved: 0x00000000
>> ..0. .... .... .... .... .... .... .... = Radiotap NS next: False
>> .0.. .... .... .... .... .... .... .... = Vendor NS next: False
>> 0... .... .... .... .... .... .... .... = Ext: False
>> MAC timestamp: 78051063
>> Flags: 0x00
>> .... ...0 = CFP: False
>> .... ..0. = Preamble: Long
>> .... .0.. = WEP: False
>> .... 0... = Fragmentation: False
>> ...0 .... = FCS at end: False
>> ..0. .... = Data Pad: False
>> .0.. .... = Bad FCS: False
>> 0... .... = Short GI: False
>> Channel frequency: 5745 [A 149]
>> Channel type: 802.11a (0x0140)
>> .... .... ...0 .... = Turbo: False
>> .... .... ..0. .... = Complementary Code Keying (CCK): False
>> .... .... .1.. .... = Orthogonal Frequency-Division
>> Multiplexing (OFDM): True
>> .... .... 0... .... = 2 GHz spectrum: False
>> .... ...1 .... .... = 5 GHz spectrum: True
>> .... ..0. .... .... = Passive: False
>> .... .0.. .... .... = Dynamic CCK-OFDM: False
>> .... 0... .... .... = Gaussian Frequency Shift Keying (GFSK): False
>> ...0 .... .... .... = GSM (900MHz): False
>> ..0. .... .... .... = Static Turbo: False
>> .0.. .... .... .... = Half Rate Channel (10MHz Channel Width): False
>> 0... .... .... .... = Quarter Rate Channel (5MHz Channel Width): False
>> SSI Signal: -53 dBm
>> Antenna: 0
>> RX flags: 0x0000
>> .... .... .... .... .... ..0. = Bad PLCP: False
>> VHT information
>> Known VHT information: 0x44
>> .... .... .... ...0 = STBC: False
>> .... .... .... ..0. = TXOP_PS_NOT_ALLOWED: False
>> .... .... .... .1.. = Guard interval: True
>> .... .... .... 0... = SGI Nsym disambiguation: False
>> .... .... ...0 .... = LDPC extra OFDM symbol: False
>> .... .... ..0. .... = Beamformed: False
>> .... .... .1.. .... = Bandwidth: True
>> .... .... 0... .... = Group ID: False
>> .... ...0 .... .... = Partial AID: False
>> .... .0.. = Guard interval: long (0)
>> Bandwidth: 80 MHz (4)
>> User 0: MCS 8
>> 1000 .... = MCS index 0: 8 (256-QAM 3/4)
>> .... 0010 = Spatial streams 0: 2
>> Space-time streams 0: 2
>> Coding 0: BCC (0)
>> [Data Rate: 702.0 Mb/s]
>> IEEE 802.11 QoS Data, Flags: .......T
>> Type/Subtype: QoS Data (0x28)
>> Frame Control Field: 0x8801
>> .... ..00 = Version: 0
>> .... 10.. = Type: Data frame (2)
>> 1000 .... = Subtype: 8
>> Flags: 0x01
>> .... ..01 = DS status: Frame from STA to DS via an AP (To
>> DS: 1 From DS: 0) (0x01)
>> .... .0.. = More Fragments: This is the last fragment
>> .... 0... = Retry: Frame is not being retransmitted
>> ...0 .... = PWR MGT: STA will stay up
>> ..0. .... = More Data: No data buffered
>> .0.. .... = Protected flag: Data is not protected
>> 0... .... = Order flag: Not strictly ordered
>> .000 0000 0011 0000 = Duration: 48 microseconds
>> Receiver address: SenaoNet_18:a8:00 (88:dc:96:18:a8:00)
>> BSS Id: SenaoNet_18:a8:00 (88:dc:96:18:a8:00)
>> Transmitter address: Apple_67:24:54 (84:38:35:67:24:54)
>> Source address: Apple_67:24:54 (84:38:35:67:24:54)
>> Destination address: SenaoNet_18:a8:00 (88:dc:96:18:a8:00)
>> Fragment number: 0
>> Sequence number: 1021
>> Qos Control: 0x0080
>> .... .... .... 0000 = TID: 0
>> [.... .... .... .000 = Priority: Best Effort (Best Effort) (0)]
>> .... .... ...0 .... = QoS bit 4: Bits 8-15 of QoS Control
>> field are TXOP Duration Requested
>> .... .... .00. .... = Ack Policy: Normal Ack (0x0000)
>> .... .... 1... .... = Payload Type: A-MSDU
>> 0000 0000 .... .... = TXOP Duration Requested: 0 (no TXOP requested)
>> IEEE 802.11 Aggregate MSDU
>> A-MSDU Subframe #1
>> Destination address: GoogleFi_00:14:cd (f8:8f:ca:00:14:cd)
>> Source address: Apple_67:24:54 (84:38:35:67:24:54)
>> A-MSDU Length: 1510
>> Logical-Link Control
>> DSAP: SNAP (0xaa)
>> IG Bit: Individual
>> SSAP: SNAP (0xaa)
>> CR Bit: Command
>> Control field: U, func=UI (0x03)
>> 000. 00.. = Command: Unnumbered Information (0x00)
>> .... ..11 = Frame type: Unnumbered frame (0x03)
>> Organization Code: Encapsulated Ethernet (0x000000)
>> Type: IP (0x0800)
>> Internet Protocol Version 4, Src: 192.168.144.79
>> (192.168.144.79), Dst: 192.168.144.13 (192.168.144.13)
>> Version: 4
>> Header length: 20 bytes
>> Differentiated Services Field: 0x00 (DSCP 0x00: Default;
>> ECN: 0x00: Not-ECT (Not ECN-Capable Transport))
>> 0000 00.. = Differentiated Services Codepoint: Default (0x00)
>> .... ..00 = Explicit Congestion Notification: Not-ECT
>> (Not ECN-Capable Transport) (0x00)
>> Total Length: 1500
>> Identification: 0xc622 (50722)
>> Flags: 0x00
>> 0... .... = Reserved bit: Not set
>> .0.. .... = Don't fragment: Not set
>> ..0. .... = More fragments: Not set
>> Fragment offset: 0
>> Time to live: 64
>> Protocol: TCP (6)
>> Header checksum: 0x0d4c [correct]
>> [Good: True]
>> [Bad: False]
>> Source: 192.168.144.79 (192.168.144.79)
>> Destination: 192.168.144.13 (192.168.144.13)
>> [Source GeoIP: Unknown]
>> [Destination GeoIP: Unknown]
>> Transmission Control Protocol, Src Port: 52697 (52697), Dst
>> Port: 5001 (5001), Seq: 1390105, Ack: 1, Len: 1448
>> Source port: 52697 (52697)
>> Destination port: 5001 (5001)
>> [Stream index: 0]
>> Sequence number: 1390105 (relative sequence number)
>> [Next sequence number: 1391553 (relative sequence number)]
>> Acknowledgment number: 1 (relative ack number)
>> Header length: 32 bytes
>> Flags: 0x010 (ACK)
>> 000. .... .... = Reserved: Not set
>> ...0 .... .... = Nonce: Not set
>> .... 0... .... = Congestion Window Reduced (CWR): Not set
>> .... .0.. .... = ECN-Echo: Not set
>> .... ..0. .... = Urgent: Not set
>> .... ...1 .... = Acknowledgment: Set
>> .... .... 0... = Push: Not set
>> .... .... .0.. = Reset: Not set
>> .... .... ..0. = Syn: Not set
>> .... .... ...0 = Fin: Not set
>> Window size value: 8235
>> [Calculated window size: 131760]
>> [Window size scaling factor: 16]
>> Checksum: 0xa1c0 [correct]
>> [Good Checksum: True]
>> [Bad Checksum: False]
>> Options: (12 bytes), No-Operation (NOP), No-Operation
>> (NOP), Timestamps
>> No-Operation (NOP)
>> Type: 1
>> 0... .... = Copy on fragmentation: No
>> .00. .... = Class: Control (0)
>> ...0 0001 = Number: No-Operation (NOP) (1)
>> No-Operation (NOP)
>> Type: 1
>> 0... .... = Copy on fragmentation: No
>> .00. .... = Class: Control (0)
>> ...0 0001 = Number: No-Operation (NOP) (1)
>> Timestamps: TSval 1298580657, TSecr 4294947481
>> Kind: Timestamp (8)
>> Length: 10
>> Timestamp value: 1298580657
>> Timestamp echo reply: 4294947481
>> Data (1448 bytes)
>>
>> 0000 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0010 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0020 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 0030 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0040 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 0050 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0060 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0070 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 0080 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0090 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 00a0 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 00b0 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 00c0 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 00d0 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 00e0 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 00f0 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0100 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0110 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 0120 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0130 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 0140 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0150 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0160 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 0170 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0180 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 0190 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 01a0 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 01b0 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 01c0 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 01d0 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 01e0 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 01f0 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0200 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 0210 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0220 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 0230 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0240 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0250 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 0260 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0270 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 0280 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0290 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 02a0 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 02b0 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 02c0 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 02d0 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 02e0 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 02f0 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 0300 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0310 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 0320 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0330 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0340 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 0350 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0360 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 0370 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0380 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0390 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 03a0 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 03b0 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 03c0 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 03d0 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 03e0 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 03f0 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0400 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 0410 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0420 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0430 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 0440 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0450 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 0460 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0470 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0480 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 0490 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 04a0 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 04b0 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 04c0 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 04d0 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 04e0 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 04f0 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 0500 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0510 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0520 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 0530 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0540 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 0550 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0560 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0570 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 0580 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0590 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 05a0 34 35 36 37 38 39 30 31 45678901
>> Data: 343536373839303132333435363738393031323334353637...
>> [Length: 1448]
>> A-MSDU Subframe #2
>> Destination address: GoogleFi_00:14:cd (f8:8f:ca:00:14:cd)
>> Source address: Apple_67:24:54 (84:38:35:67:24:54)
>> A-MSDU Length: 1510
>> Logical-Link Control
>> DSAP: SNAP (0xaa)
>> IG Bit: Individual
>> SSAP: SNAP (0xaa)
>> CR Bit: Command
>> Control field: U, func=UI (0x03)
>> 000. 00.. = Command: Unnumbered Information (0x00)
>> .... ..11 = Frame type: Unnumbered frame (0x03)
>> Organization Code: Encapsulated Ethernet (0x000000)
>> Type: IP (0x0800)
>> Internet Protocol Version 4, Src: 192.168.144.79
>> (192.168.144.79), Dst: 192.168.144.13 (192.168.144.13)
>> Version: 4
>> Header length: 20 bytes
>> Differentiated Services Field: 0x00 (DSCP 0x00: Default;
>> ECN: 0x00: Not-ECT (Not ECN-Capable Transport))
>> 0000 00.. = Differentiated Services Codepoint: Default (0x00)
>> .... ..00 = Explicit Congestion Notification: Not-ECT
>> (Not ECN-Capable Transport) (0x00)
>> Total Length: 1500
>> Identification: 0xda09 (55817)
>> Flags: 0x00
>> 0... .... = Reserved bit: Not set
>> .0.. .... = Don't fragment: Not set
>> ..0. .... = More fragments: Not set
>> Fragment offset: 0
>> Time to live: 64
>> Protocol: TCP (6)
>> Header checksum: 0xf964 [correct]
>> [Good: True]
>> [Bad: False]
>> Source: 192.168.144.79 (192.168.144.79)
>> Destination: 192.168.144.13 (192.168.144.13)
>> [Source GeoIP: Unknown]
>> [Destination GeoIP: Unknown]
>> Transmission Control Protocol, Src Port: 52697 (52697), Dst
>> Port: 5001 (5001), Seq: 1391553, Ack: 1, Len: 1448
>> Source port: 52697 (52697)
>> Destination port: 5001 (5001)
>> [Stream index: 0]
>> Sequence number: 1391553 (relative sequence number)
>> [Next sequence number: 1393001 (relative sequence number)]
>> Acknowledgment number: 1 (relative ack number)
>> Header length: 32 bytes
>> Flags: 0x010 (ACK)
>> 000. .... .... = Reserved: Not set
>> ...0 .... .... = Nonce: Not set
>> .... 0... .... = Congestion Window Reduced (CWR): Not set
>> .... .0.. .... = ECN-Echo: Not set
>> .... ..0. .... = Urgent: Not set
>> .... ...1 .... = Acknowledgment: Set
>> .... .... 0... = Push: Not set
>> .... .... .0.. = Reset: Not set
>> .... .... ..0. = Syn: Not set
>> .... .... ...0 = Fin: Not set
>> Window size value: 8235
>> [Calculated window size: 131760]
>> [Window size scaling factor: 16]
>> Checksum: 0x9a16 [incorrect, should be 0x5913 (maybe
>> caused by "TCP checksum offload"?)]
>> [Good Checksum: False]
>> [Bad Checksum: True]
>> [Expert Info (Error/Checksum): Bad checksum]
>> [Message: Bad checksum]
>> [Severity level: Error]
>> [Group: Checksum]
>> Options: (12 bytes), No-Operation (NOP), No-Operation
>> (NOP), Timestamps
>> No-Operation (NOP)
>> Type: 1
>> 0... .... = Copy on fragmentation: No
>> .00. .... = Class: Control (0)
>> ...0 0001 = Number: No-Operation (NOP) (1)
>> No-Operation (NOP)
>> Type: 1
>> 0... .... = Copy on fragmentation: No
>> .00. .... = Class: Control (0)
>> ...0 0001 = Number: No-Operation (NOP) (1)
>> Timestamps: TSval 1298580657, TSecr 4294947481
>> Kind: Timestamp (8)
>> Length: 10
>> Timestamp value: 1298580657
>> Timestamp echo reply: 4294947481
>> Data (1448 bytes)
>>
>> 0000 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0010 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 0020 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0030 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0040 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 0050 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0060 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 0070 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0080 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0090 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 00a0 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 00b0 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 00c0 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 00d0 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 00e0 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 00f0 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0100 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 0110 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0120 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0130 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 0140 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0150 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 0160 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0170 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0180 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 0190 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 01a0 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 01b0 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 01c0 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 01d0 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 01e0 32 33 34 35 36 37 38 39 30 31 72 36 35 35 36 37 2345678901r65567
>> 01f0 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 0200 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0210 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0220 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 0230 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0240 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 0250 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0260 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0270 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 0280 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0290 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 02a0 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 02b0 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 02c0 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 02d0 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 02e0 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 02f0 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0300 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0310 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 0320 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0330 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 0340 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0350 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0360 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 0370 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0380 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 0390 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 03a0 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 03b0 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 03c0 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 03d0 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 03e0 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 03f0 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0400 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 0410 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0420 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 0430 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0440 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0450 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 0460 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0470 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 0480 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0490 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 04a0 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 04b0 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 04c0 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 04d0 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 04e0 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 04f0 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 0500 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0510 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 0520 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0530 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0540 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 0550 32 33 34 35 36 37 38 39 30 31 32 33 34 35 36 37 2345678901234567
>> 0560 38 39 30 31 32 33 34 35 36 37 38 39 30 31 32 33 8901234567890123
>> 0570 34 35 36 37 38 39 30 31 32 33 34 35 36 37 38 39 4567890123456789
>> 0580 30 31 32 33 34 35 36 37 38 39 30 31 32 33 34 35 0123456789012345
>> 0590 36 37 38 39 30 31 32 33 34 35 36 37 38 39 30 31 6789012345678901
>> 05a0 32 33 34 35 36 37 38 39 23456789
>> Data: 323334353637383930313233343536373839303132333435...
>> [Length: 1448]
>>
>> On Mon, Jul 7, 2014 at 12:26 PM, Denton Gentry <denton.gentry at gmail.com> wrote:
>>> The initial results are not promising: a MacOS 802.11ac client gets
>>> between 0-2 Mbps with this change, where it was getting about 8 Mbps
>>> prior to this change and ~170 Mbps prior to the reordering fix. A pcap
>>> from the receiving system shows a very large number of out of order
>>> frames, likely due to TCP retransmission.
>>>
>>> An 802.11n MacBook gets very good throughput, only the 802.11ac
>>> MacBook shows the very poor result. I'm trying to figure out why.
>>>
>>>
>>> One specific note (and probably not related to the throughput): I
>>> believe ath10k_htt_rx_amsdu runs in the tasklet, which means it would
>>> need to use GFP_ATOMIC instead of GFP_KERNEL. Do I understand it
>>> correctly?
>>>
>>>
>>> On Mon, Jul 7, 2014 at 1:30 AM, Janusz Dziedzic
>>> <janusz.dziedzic at tieto.com> wrote:
>>>> On 6 July 2014 04:27, Adrian Chadd <adrian at freebsd.org> wrote:
>>>>> I think you may have to tell mac80211 that it's okay and not to drop the frames.
>>>>>
>>>>> The earlier atheros chips would just give you the AMSDU frames as
>>>>> deaggregated A-MPDU sub-frames - you'd just pass the A-MSDU up to
>>>>> net80211 and it'd ull it apart. But if the driver is doing it (or,
>>>>> well, the chip is doing it) then mac80211 needs to know not to drop
>>>>> those sub-frames.
>>>>>
>>>>> I wonder if you'll ever get notified before the complete A-MPDU has
>>>>> been received. That happens on previous chips. eg, you have an A-MPDU
>>>>> of 16 frames with 4 MSDUs in each MPDU. If you get notified and handle
>>>>> half of one MPDU before you hit EOL, the next notification you process
>>>>> will be the next MSDU in the same MPDU - and then you'll hit the
>>>>> reordering hilarity again.
>>>>>
>>>>> So hm, i will face the same issue in FreeBSD at some point, so I'd
>>>>> likely do what you're thinking of doing - pass up a chain of mbufs
>>>>> representing the current MPDU and treat the whole lot as the frame(s)
>>>>> to care about. Honestly though, I'm kind of wondering whether I should
>>>>> mostly just do what the Atheros reference driver does and treat it as
>>>>> ethernet payload frames (ie, it's already de-encapsulated and the
>>>>> reordering is already done) and just tack on the wifi header bit via
>>>>> another of the DMA rings.
>>>>>
>>>>> Ugh, I really should sit down and write the FreeBSD version of this.
>>>>>
>>>>>
>>>>>
>>>>> -a
>>>>>
>>>>> (I'm still having flashbacks from working on this firmware at QCA. Aiee.)
>>>>>
>>>>>
>>>>> On 5 July 2014 06:55, Denton Gentry <denton.gentry at gmail.com> wrote:
>>>>>> There are two issues in handling the dis-aggregated A-MSDU subframes
>>>>>> in ieee80211_sta_manage_reorder_buf:
>>>>>>
>>>>>> 1. The out-of-date check:
>>>>>>
>>>>>> /* frame with out of date sequence number */
>>>>>> if (ieee80211_sn_less(mpdu_seq_num, head_seq_num)) {
>>>>>> dev_kfree_skb(skb);
>>>>>> goto out;
>>>>>> }
>>>>>>
>>>>>> As all of the subframes carry the same sequence number, the first
>>>>>> subframe will be delivered and increment head_seq_num and then all
>>>>>> subsequent subframes will be discarded.
>>>>>>
>>>>>>
>>>>>> 2. The duplicates check a bit later in the routine:
>>>>>>
>>>>>> /* check if we already stored this frame */
>>>>>> if (tid_agg_rx->reorder_buf[index]) {
>>>>>> dev_kfree_skb(skb);
>>>>>> goto out;
>>>>>> }
>>>>>>
>>>>>> If there is enough packet loss that packets are queued in the reorder
>>>>>> buffer and not immediately released, then only the first subframe will
>>>>>> be stored. Subsequent subframes will be discarded as duplicates.
>>>>>>
>>>>>>
>>>>>> An 802.11ac MacBook is able to get about 170 Mbps with iperf prior to
>>>>>> the reordering buffer changes, and dropped to about 8 Mbps with the
>>>>>> reorder buffer. Hacking around the out-of-date sequence number check
>>>>>> to allow all subframes to egress restores it to 170 Mbps.
>>>>>>
>>>>>> In the area where I'm testing there isn't enough 5 GHz noise to make
>>>>>> the duplicates-check issue happen very often. By adding a printk I can
>>>>>> see that it does happen, but it doesn't impact the throughput and I
>>>>>> can't report the impact of fixing it.
>>>>>>
>>>>>> ----
>>>>>>
>>>>>> I do wonder if both of these are symptoms of dis-aggregating the
>>>>>> A-MSDU too early. mac80211 expects to be dealing with the whole MPDU
>>>>>> at a time, and the ath10k A-MSDU case is sending it subframes instead.
>>>>>> Trying to make the ath10k code send up all of the subframes as a chain
>>>>>> of skbs didn't immediately work, but I do wonder if that would better
>>>>>> match the mac80211 expectations.
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Fri, Jul 4, 2014 at 11:58 AM, Denton Gentry <denton.gentry at gmail.com> wrote:
>>>>>>> Yes, after some more testing it does look like an unfortunate
>>>>>>> interaction between the reorder buffer and A-MSDU. The disaggregated
>>>>>>> subframes all carry the same sequence number. The first subframe is
>>>>>>> released from the reorder buffer and increments the head_seq_num.
>>>>>>> Subsequent subframes are all discarded as being out of date.
>>>>>>>
>>>>>>> [ 308.514021] ieee80211_sta_manage_reorder_buf: out of date seq=0xb05
>>>>>>> head=0xb06
>>>>>>> [ 308.520577] ieee80211_sta_manage_reorder_buf: out of date seq=0xb0a
>>>>>>> head=0xb0b
>>>>>>> [ 308.527198] ieee80211_sta_manage_reorder_buf: out of date seq=0xb0f
>>>>>>> head=0xb10
>>>>>>> [ 308.533857] ieee80211_sta_manage_reorder_buf: out of date seq=0xb14
>>>>>>> head=0xb15
>>>>>>> [ 308.540480] ieee80211_sta_manage_reorder_buf: out of date seq=0xb19
>>>>>>> head=0xb1a
>>>>>>> [ 308.547730] ieee80211_sta_manage_reorder_buf: out of date seq=0xb1e
>>>>>>> head=0xb1f
>>>>>>> [ 308.554069] ieee80211_sta_manage_reorder_buf: out of date seq=0xb23
>>>>>>> head=0xb24
>>>>>>>
>>>>>>>
>>>>>>> On Wed, Jul 2, 2014 at 9:49 AM, Michal Kazior <michal.kazior at tieto.com> wrote:
>>>>>>>> On 30 June 2014 22:15, Denton Gentry <denton.gentry at gmail.com> wrote:
>>>>>>>>> In iperf tests using a MacBook STA bridging through an ath10k AP to an
>>>>>>>>> Ethernet server, I'm noticing very selective packet loss. The second
>>>>>>>>> and subsequent frames in an A-MSDU packet appear to be dropped.
>>>>>>>>>
>>>>>>>>> The AP sets the A-MSDU size to 3839 bytes, and the MacBook frequently
>>>>>>>>> sends A-MSDU packets containing two TCP frames. So far as I can tell,
>>>>>>>>> the first TCP frame from an A-MSDU aggregate is delivered and the
>>>>>>>>> second is consistently lost. The MacBook generally retransmits the
>>>>>>>>> lost frame as a singleton with no aggregation, and the retransmitted
>>>>>>>>> frame makes it through.
>>>>>>>>>
>>>>>>>>> This became more noticeable after the reordering fixes in
>>>>>>>>> http://lists.infradead.org/pipermail/ath10k/2014-June/002552.html
>>>>>>>>>
>>>>>>>>> I see this A-MSDU packet loss behavior both with and without the
>>>>>>>>> reordering fixes, the first packet in an A-MSDU is delivered while the
>>>>>>>>> second is dropped. However, *without* the reordering fixes (and
>>>>>>>>> therefore with packets delivered out of order) the MacBook sends
>>>>>>>>> relatively few A-MSDU frames. *With* the reordering fixes, so all
>>>>>>>>> packets are delivered in order, the MacBook keeps sending A-MSDU and
>>>>>>>>> therefore has to deal with more packet loss. I suspect it is an
>>>>>>>>> interaction with the MacOS TCP congestion window which I'm likely
>>>>>>>>> never going to fully understand, its stuck in a region of the
>>>>>>>>> congestion window where the Wifi driver keeps choosing to using
>>>>>>>>> A-MSDU.
>>>>>>>>
>>>>>>>> I was actually worried about A-MSDU once A-MPDU re-ordering issue was raised.
>>>>>>>>
>>>>>>>> ath10k fw reports A-MSDU subframes separately. To avoid memory
>>>>>>>> copying/allocation overhead each subframe is reported as a singly
>>>>>>>> A-MSDU MSDU to mac80211 with an extra rx_flag AMSDU_MORE. Perhaps
>>>>>>>> A-MPDU reordering intereferes with A-MSDU now?
>>>>>>>>
>>>> Denton could you try attached patch: report amsdu in one big frame.
>>>> If help, we can add amsdu skb list support to mac80211/cfg80211 - to
>>>> improve performance and reduce memcpy, while currently we have skb
>>>> frames, put them in one big skb and next cfg80211 split them again
>>>> into msdus and report to stack.
>>>>
>>>> BR
>>>> Janusz
More information about the ath10k
mailing list