Re: [tcpdump-workers] Hardware Timestamping Problem

On Jun 9, 2016, at 4:47 PM, Guenter Ebermann wrote: > They are only delivered to the socket on which the packet was sent, not to > all PF_PACKET sockets. Then Christian can't get what I think he wants with libpcap - or anything else doing PF_PACKET socket

Re: [tcpdump-workers] Hardware Timestamping Problem

> Am 10.06.2016 um 01:35 schrieb Guy Harris : > > On Jun 9, 2016, at 4:09 PM, Guenter Ebermann > wrote: > >> >>> Am 10.06.2016 um 00:13 schrieb Guy Harris : >>> >>> But that doesn't mean that the packets time stamped by

Re: [tcpdump-workers] Hardware Timestamping Problem

On Jun 9, 2016, at 4:09 PM, Guenter Ebermann wrote: > >> Am 10.06.2016 um 00:13 schrieb Guy Harris : >> >> But that doesn't mean that the packets time stamped by the hardware when >> transmitted will be delivered to the PF_PACKET sockets

Re: [tcpdump-workers] Hardware Timestamping Problem

> Am 10.06.2016 um 00:13 schrieb Guy Harris : > > But that doesn't mean that the packets time stamped by the hardware when > transmitted will be delivered to the PF_PACKET sockets used by libpcap *with > the hardware time stamp as the time stamp*. > > In order make that

Re: [tcpdump-workers] Hardware Timestamping Problem

On Jun 9, 2016, at 1:19 PM, Guenter Ebermann wrote: >> Am 09.06.2016 um 15:47 schrieb Michael Richardson : >> >> Guenter Ebermann wrote: >>> Hardware timestamping of sending/receiving buffer descriptors is

Re: [tcpdump-workers] Hardware Timestamping Problem

> Am 09.06.2016 um 15:47 schrieb Michael Richardson : > > Guenter Ebermann wrote: >> Hardware timestamping of sending/receiving buffer descriptors is done >> by NIC. > > Receiving I understand. > > Are you sure that the hardware is going to

Re: [tcpdump-workers] Hardware Timestamping Problem

The experiments I made today actually suggest that in my case tcpdump uses the hardware clock for incoming packages and the software/unix clock for outgoing packages. I changed the System clock of one Server with date -s and then looked at the capture of Ping packages. Incoming packages on

Re: [tcpdump-workers] Hardware Timestamping Problem

Guenter Ebermann wrote: > Hardware timestamping of sending/receiving buffer descriptors is done > by NIC. Receiving I understand. Are you sure that the hardware is going to timestamp sent packets, and then turn around and send the back to the kernel? --

Re: [tcpdump-workers] Hardware Timestamping Problem

Yes, the exact same packet. Am 08.06.2016 um 22:40 schrieb Guy Harris: On Jun 8, 2016, at 1:29 PM, Christian Rupp wrote: The Timestamp when tcpdump grabs the package off of the receiver is 36 seconds( +/- innaccuracy, here roughly +/- 5-10 µs) after

Re: [tcpdump-workers] Hardware Timestamping Problem

> Am 08.06.2016 um 23:10 schrieb Michael Richardson : > > Christian Rupp wrote: >> The Timestamp when tcpdump grabs the package off of the receiver is 36 >> seconds( +/- innaccuracy, here roughly +/- 5-10 µs) after the timestamp when >>

Re: [tcpdump-workers] Hardware Timestamping Problem

The Timestamp when tcpdump grabs the package off of the receiver is 36 seconds( +/- innaccuracy, here roughly +/- 5-10 µs) after the timestamp when tcpdump grabs the package of the sender. resulting in an alleged One Way Delay of 36 seconds which wouldn't make any sense in that scenario,

Re: [tcpdump-workers] Hardware Timestamping Problem

On Jun 8, 2016, at 5:53 AM, Christian wrote: > Now, my results in itself make sense and would give me the desired results, > but they have a big offset to them. 36 seconds to be exact. So you're saying there's a 36-second offset between which two times?

Re: [tcpdump-workers] Hardware Timestamping Problem

{please keep it on the list for archival purposes} Christian wrote: > between sender and receiver > so from the point when tcpdump grabs the time off of the Sender and to the > point where tcpdump grabs the time off of the receiver. So you are

Re: [tcpdump-workers] Hardware Timestamping Problem

Christian wrote: > My Setup: > 2 directly connected identical Servers. > Linux: Debian 3.16.7 > Network Interface: Intel i350-T4 > Used tcpdump command: > sudo /usr/sbin/tcpdump -i eth4 -s 59 port 3 -x -n -tt -v -j >