The current handling of echoed IP timestamp options with prespecified
addresses is rather broken since the 2.2.x kernels. As far as i understand
it, it should behave like when originating packets.
Currently it will only timestamp the next free slot if:
- there is space for *two* timestamps
- some random data from the echoed packet taken as an IP is *not* a local IP
This first is caused by an off-by-one error. 'soffset' points to the next
free slot and so we only need to have 'soffset + 7 <= optlen'.
The second bug is using sptr as the start of the option, when it really is
set to 'skb_network_header(skb)'. I just use dptr instead which points to
the timestamp option.
Finally it would only timestamp for non-local IPs, which we shouldn't do.
So instead we exclude all unicast destinations, similar to what we do in
ip_options_compile().
Signed-off-by: Jan Luebbe <jluebbe@debian.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
8628bd8af7