svn commit: r280971 - in head: contrib/ipfilter/tools share/man/man4 sys/contrib/ipfilter/netinet sys/netinet sys/netipsec sys/netpfil/pf

[Robert N. M. Watson]

On 2 Apr 2015, at 19:24, Hans Petter Selasky <hps at selasky.org> wrote:

> In my sketchup I assume that packets for the same destination will not be re-ordered. I see that the current ip_reass() code does not care about TCP or UDP port numbers at all. Maybe we should add code to check that the packet belongs to the same ports too?

Higher-level network headers will appear only in the first fragment, so can't be used in matching later fragments.

> Does somebody here know what happens in these two cases:
> 
> If we are transmitting using TSO, will the network adapter increment the IP ID field somehow? What happens if an outgoing IP packet resulting from a TSO packet get fragmented by a router?

Quite possibly -- this is presumably specified by the NIC vendor, but it would be good to do a bit of a survey and see what happens in practice.

> In ip_fragment() when we create fragments we should increment the ip_id value for each fragment?


That you are asking this question while hacking on the IP ID code is deeply troubling. Please go read up on how IP fragmentation works before going any further with these changes!

Robert