EDNS optimizations

Knot caches pointers to relevant EDNS options during packet parsing. This is useful when we quickly need to fetch an option from the OPT RR, such as NSID or COOKIE, without having to traverse through the entire OPT RR.

added 44 commits

• 96cb90e9...41dc8c43 - 42 commits from branch master
• 8ec90063 - stats: added counters for EDNS option codes
• 8d2bd701 - libknot: added caching of pointers to known options in OPT RR

Compare with previous version

added 21 commits

• 8d2bd701...7fec60c9 - 20 commits from branch master
• b29fc3cb - libknot: added caching of pointers to known options in OPT RR

Compare with previous version

changed title from EDNS: optimizations and statistics to EDNS optimizations

changed the description

added 29 commits

• 6f69a28f...14e6250a - 27 commits from branch master
• f6f36748 - libknot/opt: remove useless operations
• 2f31b404 - libknot/edns: added caching of pointers to known options in OPT RR, refactoring

Compare with previous version

added 6 commits

• 2f31b404...646a3cb8 - 2 commits from branch master
• 0c14e4d0 - libknot/opt: remove useless operations
• b5ced57a - libknot/edns: added caching of pointers to known options in OPT RR, refactoring
• 494e9e29 - libknot/edns: unify option length data type to uint16_t
• 85d90d14 - libknot: replace knot_edns_default_padding_size with knot_pkt_default_padding_size

Compare with previous version

enabled an automatic merge when the pipeline for 85d90d14 succeeds

merged

mentioned in commit 693b7f75