Cache entire DNS response and not only the answer section

[0xERR0R]

Currently, blocky caches only the answer section from the DNS response.

It would be better to cache the entire DNS response (anser, authority section etc.).

[alpominth]

I think this would be easy to implement, here an example with a little toy DNS app: https://github.com/orivej/dnscache

$ go install github.com/orivej/dnscache@latest

$ go/bin/dnscache -listen 127.0.0.1:1053 -upstream 1.1.1.1:53
2023/01/20 09:12:18.642838 87C2┐g.co. PTR IN
2023/01/20 09:12:18.871154 87C2└g.co. PTR IN = 
^C

user@localhost:~$ time dig @127.0.0.1 -p 1053 -t PTR g.co
; <<>> DiG 9.18.10-2-Debian <<>> @127.0.0.1 -p 1053 -t PTR g.co
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 34754
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;g.co.				IN	PTR
;; AUTHORITY SECTION:
g.co.			46	IN	SOA	ns1.google.com. dns-admin.google.com. 503115268 900 900 1800 60
;; Query time: 227 msec
;; SERVER: 127.0.0.1#1053(127.0.0.1) (UDP)
;; WHEN: Fri Jan 20 09:12:18 EST 2023
;; MSG SIZE  rcvd: 107
real	0m0.250s
user	0m0.006s
sys	0m0.006s

$ time dig @127.0.0.1 -p 1053 -t PTR g.co
; <<>> DiG 9.18.10-2-Debian <<>> @127.0.0.1 -p 1053 -t PTR g.co
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 56350
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;g.co.				IN	PTR
;; AUTHORITY SECTION:
g.co.			46	IN	SOA	ns1.google.com. dns-admin.google.com. 503115268 900 900 1800 60
;; Query time: 0 msec
;; SERVER: 127.0.0.1#1053(127.0.0.1) (UDP)
;; WHEN: Fri Jan 20 09:12:19 EST 2023
;; MSG SIZE  rcvd: 107
real	0m0.021s
user	0m0.004s
sys	0m0.006s

It's a pitty that I don't know how to code in Go, if not I could modify Blocky by myself.

[alpominth]

I noticed that Blocky doesn't cache the OPT pseudosection:

$ time dig @127.0.0.1 -p 1053 www.linux.bogus

; <<>> DiG 9.18.10-2-Debian <<>> @127.0.0.1 -p 1053 www.linux.bogus
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 32153
;; flags: qr rd ra ad; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;www.linux.bogus.		IN	A

;; AUTHORITY SECTION:
.			44469	IN	SOA	a.root-servers.net. nstld.verisign-grs.com. 2023012500 1800 900 604800 86400

;; Query time: 270 msec
;; SERVER: 127.0.0.1#1053(127.0.0.1) (UDP)
;; WHEN: Wed Jan 25 13:09:50 EST 2023
;; MSG SIZE  rcvd: 119


real	0m0.292s
user	0m0.006s
sys	0m0.006s
$ time dig @127.0.0.1 -p 1053 www.linux.bogus

; <<>> DiG 9.18.10-2-Debian <<>> @127.0.0.1 -p 1053 www.linux.bogus
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 30175
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;www.linux.bogus.		IN	A

;; Query time: 0 msec
;; SERVER: 127.0.0.1#1053(127.0.0.1) (UDP)
;; WHEN: Wed Jan 25 13:09:53 EST 2023
;; MSG SIZE  rcvd: 33


real	0m0.021s
user	0m0.007s
sys	0m0.004s