Hi Robin,
On 31/07/2024 16:04, Robin Jarry wrote:
Hi Vladimir,
I noticed that the fib/rib APIs (both IPv4 and IPv6) require the next
hops to be represented as integer indexes. Reading the code, I noticed
that they are stored as uint64_t with the MSB used for internal purposes.
I believe you are asking about FIB, not RIB. In current FIB
implementation 1 LSB is used for internal purposes.
This require either having a contiguous array of nexthop objects and
choose an index in that array,
As far as I know that's what most of "l3 forward" applications (aka
routers) are doing, if they are interested in performance. Not only DPDK
powered.
or store pointer offsets as nexthop indexes and do pointer arithmetics
to reconstruct the real pointers. Both are not very practical and/or
hacky.
Would it be possible to store arbitrary pointers? That would mean
moving that 64th bit information elsewhere.
For arbitrary pointer - no, since it needs to store 1 more bit for
internal purpose. However, if you have 2 byte aligned pointer you can
store the pointer shifted right by 1 bit, and after lookup just shift
the result back.
I'd love to hear what you think on the matter.
Cheers,
Robin
--
Regards,
Vladimir
