On Sun, Apr 23, 2017 at 01:44:51PM -0400, Jamal Hadi Salim wrote:
>
> Thanks for the excellent work.
>
> On 17-04-23 08:53 AM, Amir Vadai wrote:
> > This command could be useful to increase/decrease fields value.
> >
>
> Does this contradict the "retain" feature? Example rule to
> retain the second nibble but set the first to 0xA
> (essentially it X-ORs):
> tc filter add dev lo parent ffff: protocol ip prio 10 \
> u32 match ip dst 127.0.0.1/32 flowid 1:1 \
> action pedit munge offset 0 u8 set 0x0A retain 0xF0
You mean, for example increasing a single nible in an ipv4 address?
If so, then it should work:
# tc filter add dev veth0 parent ffff: u32 \
match ip dport 23 0xffff \
action pedit ex \
munge ip src add 1.0.0.0 retain 0xff000000
# tc -s filter show dev veth0 parent ffff:
filter protocol all pref 49151 u32
filter protocol all pref 49151 u32 fh 801: ht divisor 1
filter protocol all pref 49151 u32 fh 801::800 order 2048 key ht 801 bkt 0
terminal flowid ??? (rule hit 0 success 0)
match 00000017/0000ffff at 20 (success 0 )
action order 1: pedit action pass keys 1
index 48 ref 1 bind 1 installed 1 sec used 1 sec
key #0 at ipv4+12: add 01000000 mask 00ffffff
Action statistics:
Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
>
> Mostly curious about hardware handling.
As to hardware handling, Or did the implementation so he will answer
better. AFAIK, current implementation doesn't allow partial field
setting/adding, so such a rule can't be offloaded. I think it is only to
make things simple and because there was no use case for that.
To my knowledge, hardware should support such thing if needed.
Amir
>
> cheers,
> jamal
>
