On Aug 17, 2011, at 2:57 PM, Fabrizio Giordano wrote: > Do you guys know where packets are timestamped in the kernel? > I'm using a 2.6.32-131.4.1.el6.x86_64 kernel
I.e., Linux, of somewhat recent vintage. The time stamp would be in the skb->tstamp field for the packet in question. If the adapter doesn't do hardware timestamps, the time stamp would be set in a call to the __net_timestamp() inline function from the skbuff.h header file, at least according to my 2.6.32.4 kernel tree. That's called by net_timestamp() in net/core/dev.c, which is called from netif_rx() or netif_receive_skb(). Those appear to be called from the network adapter driver; they're called to hand incoming packets to the networking stack. In, for example, the ixgb driver, it's called from ixgb_clean_rx_irq(). Executive summary: packets are, in general, timestamped when they're first handed to the networking stack.- This is the tcpdump-workers list. Visit https://cod.sandelman.ca/ to unsubscribe.
