1. Home
  2. Embedded Linux
  3. IP protocol checksum errors

IP protocol checksum errors

Hi

can someone (help me) solve this ? frames are captured with etherreal this happens when using a coldfire base dnp5280 board on a heavy loaded network.

The board keeps resending the badly created packets.

Need a sollution urgently !

Frame 3484 (254 on wire, 254 captured) Arrival Time: Dec 30, 2006 23:55:43.758822000 Time delta from previous packet: 0.811065000 seconds Time relative to first packet: 47.427310000 seconds Frame Number: 3484 Packet Length: 254 bytes Capture Length: 254 bytes Ethernet II Destination: 00:09:f3:0f:22:dc (WELL_0f:22:dc) Source: 02:80:ad:20:b8:b2 (02:80:ad:20:b8:b2) Type: IP (0x0800) Internet Protocol, Src Addr: 192.168.1.61 (192.168.1.61), Dst Addr: dD577BF9E.access.telenet.be (213.119.191.158) Version: 4 Header length: 20 bytes Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00) 0000 00.. = Differentiated Services Codepoint: Default (0x00) .... ..0. = ECN-Capable Transport (ECT): 0 .... ...0 = ECN-CE: 0 Total Length: 240 Identification: 0x030f Flags: 0x04 .1.. = Don't fragment: Set ..0. = More fragments: Not set Fragment offset: 0 Time to live: 64 Protocol: TCP (0x06) Header checksum: 0xdffd (correct) Source: 192.168.1.61 (192.168.1.61) Destination: dD577BF9E.access.telenet.be (213.119.191.158) Transmission Control Protocol, Src Port: 2050 (2050), Dst Port: 2126 (2126), Seq: 1948016716, Ack: 471731837, Len: 200 Source port: 2050 (2050) Destination port: 2126 (2126) Sequence number: 1948016716 Next sequence number: 1948016916 Acknowledgement number: 471731837 Header length: 20 bytes Flags: 0x0018 (PSH, ACK) 0... .... = Congestion Window Reduced (CWR): Not set .0.. .... = ECN-Echo: Not set ..0. .... = Urgent: Not set ...1 .... = Acknowledgment: Set .... 1... = Push: Set .... .0.. = Reset: Not set .... ..0. = Syn: Not set .... ...0 = Fin: Not set Window size: 5840 Checksum: 0x69cc (correct) Data (200 bytes)

0000 00 09 f3 0f 22 dc 02 80 ad 20 b8 b2 08 00 45 00 ....".... ....E. 0010 00 f0 03 0f 40 00 40 06 df fd c0 a8 01 3d d5 77 ....@.@......=.w 0020 bf 9e 08 02 08 4e 74 1c 60 4c 1c 1e 0e 7d 50 18 .....Nt.`L...}P. 0030 16 d0 69 cc 00 00 68 65 6c 6c 6f 20 77 6f 72 6c ..i...hello worl 0040 64 31 31 37 20 20 20 20 20 20 20 20 20 20 20 20 d117 0050 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 0060 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 0070 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 0080 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 0090 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 00a0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 00b0 20 20 20 0a 0d 00 23 23 23 23 23 23 23 23 23 23 ...########## 00c0 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 ################ 00d0 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 ################ 00e0 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 ################ 00f0 23 23 23 23 23 23 23 23 23 23 23 23 23 23 ##############

Frame 3497 (60 on wire, 60 captured) Arrival Time: Dec 30, 2006 23:55:43.953376000 Time delta from previous packet: 0.194554000 seconds Time relative to first packet: 47.621864000 seconds Frame Number: 3497 Packet Length: 60 bytes Capture Length: 60 bytes Ethernet II Destination: 02:80:ad:20:b8:b2 (02:80:ad:20:b8:b2) Source: 00:09:f3:0f:22:dc (WELL_0f:22:dc) Type: IP (0x0800) Trailer: 2A51DBC67616 Internet Protocol, Src Addr: dD577BF9E.access.telenet.be (213.119.191.158), Dst Addr: 192.168.1.61 (192.168.1.61) Version: 4 Header length: 20 bytes Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00) 0000 00.. = Differentiated Services Codepoint: Default (0x00) .... ..0. = ECN-Capable Transport (ECT): 0 .... ...0 = ECN-CE: 0 Total Length: 40 Identification: 0xf35a Flags: 0x04 .1.. = Don't fragment: Set ..0. = More fragments: Not set Fragment offset: 0 Time to live: 120 Protocol: TCP (0x06) Header checksum: 0xb879 (correct) Source: dD577BF9E.access.telenet.be (213.119.191.158) Destination: 192.168.1.61 (192.168.1.61) Transmission Control Protocol, Src Port: 2126 (2126), Dst Port: 2050 (2050), Seq: 471731837, Ack: 1948016916, Len: 0 Source port: 2126 (2126) Destination port: 2050 (2050) Sequence number: 471731837 Acknowledgement number: 1948016916 Header length: 20 bytes Flags: 0x0010 (ACK) 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: 16520 Checksum: 0x0835 (correct)

0000 02 80 ad 20 b8 b2 00 09 f3 0f 22 dc 08 00 45 00 ... ......"...E. 0010 00 28 f3 5a 40 00 78 06 b8 79 d5 77 bf 9e c0 a8 .(. snipped-for-privacy@.x..y.w.... 0020 01 3d 08 4e 08 02 1c 1e 0e 7d 74 1c 61 14 50 10 .=.N.....}t.a.P. 0030 40 88 08 35 00 00 2a 51 db c6 76 16 @..5..*Q..v.

Frame 3667 (254 on wire, 254 captured) Arrival Time: Dec 30, 2006 23:55:46.028327000 Time delta from previous packet: 2.074951000 seconds Time relative to first packet: 49.696815000 seconds Frame Number: 3667 Packet Length: 254 bytes Capture Length: 254 bytes Ethernet II Destination: 00:09:f3:0f:22:dc (WELL_0f:22:dc) Source: 02:80:ad:20:b8:b2 (02:80:ad:20:b8:b2) Type: IP (0x0800) Internet Protocol, Src Addr: 192.168.1.61 (192.168.1.61), Dst Addr: dD577BF9E.access.telenet.be (213.119.191.158) Version: 4 Header length: 20 bytes Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00) 0000 00.. = Differentiated Services Codepoint: Default (0x00) .... ..0. = ECN-Capable Transport (ECT): 0 .... ...0 = ECN-CE: 0 Total Length: 240 Identification: 0x0312 Flags: 0x04 .1.. = Don't fragment: Set ..0. = More fragments: Not set Fragment offset: 0 Time to live: 64 Protocol: TCP (0x06) Header checksum: 0xdffa (correct) Source: 192.168.1.61 (192.168.1.61) Destination: dD577BF9E.access.telenet.be (213.119.191.158) Transmission Control Protocol, Src Port: 2050 (2050), Dst Port: 2126 (2126), Seq: 1948016916, Ack: 471731837, Len: 200 Source port: 2050 (2050) Destination port: 2126 (2126) Sequence number: 1948016916 Next sequence number: 1948017116 Acknowledgement number: 471731837 Header length: 20 bytes Flags: 0x0018 (PSH, ACK) 0... .... = Congestion Window Reduced (CWR): Not set .0.. .... = ECN-Echo: Not set ..0. .... = Urgent: Not set ...1 .... = Acknowledgment: Set .... 1... = Push: Set .... .0.. = Reset: Not set .... ..0. = Syn: Not set .... ...0 = Fin: Not set Window size: 5840 Checksum: 0x6903 (incorrect, should be 0xaf49) Data (200 bytes)

0000 00 09 f3 0f 22 dc 02 80 ad 20 b8 b2 08 00 45 00 ....".... ....E. 0010 00 f0 03 12 40 00 40 06 df fa c0 a8 01 3d d5 77 ....@.@......=.w 0020 bf 9e 08 02 08 4e 74 1c 61 14 1c 1e 0e 7d 50 18 .....Nt.a....}P. 0030 16 d0 69 03 00 00 00 00 00 00 68 65 6c 6c 6f 20 ..i.......hello 0040 77 6f 72 6c 64 31 31 38 20 20 20 20 20 20 20 20 world118 0050 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 0060 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 0070 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 0080 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 0090 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 00a0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 00b0 20 20 20 20 20 20 20 0a 0d 00 23 23 23 23 23 23 ...###### 00c0 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 ################ 00d0 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 ################ 00e0 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 ################ 00f0 23 23 23 23 23 23 23 23 23 23 23 23 23 23 ##############

Frame 3790 (254 on wire, 254 captured) Arrival Time: Dec 30, 2006 23:55:47.708810000 Time delta from previous packet: 1.680483000 seconds Time relative to first packet: 51.377298000 seconds Frame Number: 3790 Packet Length: 254 bytes Capture Length: 254 bytes Ethernet II Destination: 00:09:f3:0f:22:dc (WELL_0f:22:dc) Source: 02:80:ad:20:b8:b2 (02:80:ad:20:b8:b2) Type: IP (0x0800) Internet Protocol, Src Addr: 192.168.1.61 (192.168.1.61), Dst Addr: dD577BF9E.access.telenet.be (213.119.191.158) Version: 4 Header length: 20 bytes Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00) 0000 00.. = Differentiated Services Codepoint: Default (0x00) .... ..0. = ECN-Capable Transport (ECT): 0 .... ...0 = ECN-CE: 0 Total Length: 240 Identification: 0x0313 Flags: 0x04 .1.. = Don't fragment: Set ..0. = More fragments: Not set Fragment offset: 0 Time to live: 64 Protocol: TCP (0x06) Header checksum: 0xdff9 (correct) Source: 192.168.1.61 (192.168.1.61) Destination: dD577BF9E.access.telenet.be (213.119.191.158) Transmission Control Protocol, Src Port: 2050 (2050), Dst Port: 2126 (2126), Seq: 1948016916, Ack: 471731837, Len: 200 Source port: 2050 (2050) Destination port: 2126 (2126) Sequence number: 1948016916 Next sequence number: 1948017116 Acknowledgement number: 471731837 Header length: 20 bytes Flags: 0x0018 (PSH, ACK) 0... .... = Congestion Window Reduced (CWR): Not set .0.. .... = ECN-Echo: Not set ..0. .... = Urgent: Not set ...1 .... = Acknowledgment: Set .... 1... = Push: Set .... .0.. = Reset: Not set .... ..0. = Syn: Not set .... ...0 = Fin: Not set Window size: 5840 Checksum: 0x6903 (incorrect, should be 0xd26c) Data (200 bytes)

0000 00 09 f3 0f 22 dc 02 80 ad 20 b8 b2 08 00 45 00 ....".... ....E. 0010 00 f0 03 13 40 00 40 06 df f9 c0 a8 01 3d d5 77 ....@.@......=.w 0020 bf 9e 08 02 08 4e 74 1c 61 14 1c 1e 0e 7d 50 18 .....Nt.a....}P. 0030 16 d0 69 03 00 00 00 00 00 00 00 00 68 65 6c 6c ..i.........hell 0040 6f 20 77 6f 72 6c 64 31 31 38 20 20 20 20 20 20 o world118 0050 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 0060 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 0070 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 0080 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 0090 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 00a0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 00b0 20 20 20 20 20 20 20 20 20 0a 0d 00 23 23 23 23 ...#### 00c0 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 ################ 00d0 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 ################ 00e0 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 23 ################ 00f0 23 23 23 23 23 23 23 23 23 23 23 23 23 23 ##############

_______________________________________________

Reply to
Sagaert Johan
Loading thread data ...

[trace snipped]

The FAQ for Wireshark (the new name for Ethereal) might explain your checksum errors.

formatting link

If packets are really being corrupted, the output might be as follows:

No. Time Source Destination Protocol Info 1 0.000000 172.16.2.121 10.1.145.49 TCP scrabble > rds [SYN] Seq=0 Len=0 MSS=1332 2 1.739607 10.1.145.49 172.16.2.121 TCP rds > scrabble [SYN, ACK] Seq=0 Ack=1 Win=11680 Len=0 MSS=1404 3 1.739653 172.16.2.121 10.1.145.49 TCP scrabble > rds [ACK] Seq=1 Ack=1 Win=65535 Len=0 4 5.119783 172.16.2.121 10.1.145.49 TCP scrabble > rds [PSH, ACK] Seq=1 Ack=1 Win=65535 Len=1 5 6.113879 10.1.145.49 172.16.2.121 ICMP Parameter problem (IP header bad) 6 6.116265 10.1.145.49 172.16.2.121 ICMP Parameter problem (IP header bad) 7 8.008623 172.16.2.121 10.1.145.49 TCP [TCP Retransmission] scrabble > rds [PSH, ACK] Seq=1 Ack=1 Win=65535 Len=12 8 14.024494 172.16.2.121 10.1.145.49 TCP [TCP Retransmission] scrabble > rds [PSH, ACK] Seq=1 Ack=1 Win=65535 Len=12 9 15.171830 10.1.145.49 172.16.2.121 ICMP Parameter problem (IP header bad) 10 15.174285 10.1.145.49 172.16.2.121 ICMP Parameter problem (IP header bad) 11 26.056089 172.16.2.121 10.1.145.49 TCP [TCP Retransmission] scrabble > rds [PSH, ACK] Seq=1 Ack=1 Win=65535 Len=12

This trace was from a system with a faulty Ethernet port in its GPRS router. The problem went away when the router was replaced.

The ICMP messages (packets 5 and 6) indicate that something is amiss.

--
Chris Isbell
Southampton, UK
Reply to
Chris Isbell

Your choices...

- Look for an updated 2.6 ethernet driver

- Revert back to 2.4

- Use a PCI ethernet card with a bug free 2.6 driver

- Fix the 2.6 driver you're using

The root cause is that 2.6 changed some of the semantics around hardware checksums, and some 2.4 drivers that were simply rewrapped for 2.6 don't do it right. It particularly happens during TCP retransmits, where the segment has grown from the previous time.

2.6 changed (or rather nailed down) the semantics because it added functionality that actually requires it. (Such as coalescing TCP segments for retransmit. If the driver ignores the flag indicating an invalid checksum the datagram may go out with the old ip csum, or no csum, or a completely bogus random value.)
Reply to
Jan Brittenson

Hi

I replaced the fec.c code in the kernel 2.4.22 sources with a version from the 2.4.31 recompiled the kernel and flashed the new kernel into the uclinux board. The problem is solved as i can't reproduce it any more.

Johan

Reply to
Sagaert Johan

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.