On 2024-06-24, Tom Smyth <[email protected]> wrote: > Folks, > while reviewing nsh I was wondering how to improve show route commands... > reviewing the man route man page, > > there doesnt seem to be a straight forward way of displaying > blackhole routes without using > > route show |grep B for blackhole > > route show |grep R for Reject > > is there something Im missing, > > would I be better off improving route(8) rather than stringing > commands together for NSH ?
It's not an efficient operation in the first place; kernel lookup is done with the address/prefix as a key and the flags (B/R etc) are only found once you've fetched a route (similar if you wanted to e.g. find routes with a specific destination router). In order to find all routes with a certain flag you do need to dump the whole route table and check it. It could be done slightly more efficiently with a check for the relevant flag rather than going via a text processing tool like grep, but I bet the actual overall time isn't going to be very different...
