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* dumpcap w/ pcapng produces out of order/negative times
@ 2022-01-14  2:38 Ben Magistro
  2022-01-14 16:15 ` Stephen Hemminger
  0 siblings, 1 reply; 2+ messages in thread
From: Ben Magistro @ 2022-01-14  2:38 UTC (permalink / raw)
  To: dev, stephen; +Cc: ben.magistro


[-- Attachment #1.1: Type: text/plain, Size: 658 bytes --]

While utilizing dumpcap with our app, we have observed the captured file
producing out of order timestamps to include negative times.  We are still
investigating the root cause but believe it is in lib/pcapng.  While doing
some testing of this issue, this behavior was not observed with pcap.  In
the attached pcap, there are 5 streams (same curl multiple times a few
seconds apart), with streams 1 and 3 showing oddities.  Specifically,
stream 1 is in the future relative to the packet order and stream 3 has a
negative time.

Not sure if the pcap file will actual post/attach, if it doesn't will try
something.

System: CentOS7 + devtoolset 9
DPDK: v21.11

[-- Attachment #1.2: Type: text/html, Size: 751 bytes --]

[-- Attachment #2: 1060.pcapng --]
[-- Type: application/octet-stream, Size: 8820 bytes --]

^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: dumpcap w/ pcapng produces out of order/negative times
  2022-01-14  2:38 dumpcap w/ pcapng produces out of order/negative times Ben Magistro
@ 2022-01-14 16:15 ` Stephen Hemminger
  0 siblings, 0 replies; 2+ messages in thread
From: Stephen Hemminger @ 2022-01-14 16:15 UTC (permalink / raw)
  To: Ben Magistro; +Cc: dev, ben.magistro

On Thu, 13 Jan 2022 21:38:06 -0500
Ben Magistro <koncept1@gmail.com> wrote:

> While utilizing dumpcap with our app, we have observed the captured file
> producing out of order timestamps to include negative times.  We are still
> investigating the root cause but believe it is in lib/pcapng.  While doing
> some testing of this issue, this behavior was not observed with pcap.  In
> the attached pcap, there are 5 streams (same curl multiple times a few
> seconds apart), with streams 1 and 3 showing oddities.  Specifically,
> stream 1 is in the future relative to the packet order and stream 3 has a
> negative time.
> 
> Not sure if the pcap file will actual post/attach, if it doesn't will try
> something.
> 
> System: CentOS7 + devtoolset 9
> DPDK: v21.11

The library hast convert from TSC (cpu clock) to nanoseconds since 1/1/1970
The function pcapng_init computes the offset. 

^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2022-01-14 16:15 UTC | newest]

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2022-01-14  2:38 dumpcap w/ pcapng produces out of order/negative times Ben Magistro
2022-01-14 16:15 ` Stephen Hemminger

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