(arm version) DNS lookup failed: read udp: read: connection refused

[binus]

version fa7eda0, with ignore_local_dns ON
go build arm version
cmd: ./gof -up="cf://$$:80" -k="$$" -l=":8100" -web-port="8101" -lv=dbg -g -U=http
firefox -> SwitchyOmega -> gof:socks5
Errror only occurs in arm version. Linux x86 and windows are all good.

UTC,main.go:266, INFO ,goflyway devel
main.go:277, WARNING ,Failed to read ACL config: open chinalist.txt: no such file or directory
main.go:435, INFO ,Upstream config: cf://$$:80
main.go:308, INFO ,Global proxy enabled
main.go:415, INFO ,Client fb16884 started: you->0.0.0.0:8100->cloudflare->$$:80
main.go:411, INFO ,Web console started at 127.0.0.1:8101
acl.go:42, INFO ,ACL check result: unknown >> 7 ## I added acl.go:42 to print the debug info
acl.go:43, ERROR ,ACL check error: DNS lookup failed: lookup google.com on [::1]:53: read udp [::1]:39998->[::1]:53: read: connection refused ## this is the original acl.go:42 debug print
client.go:538, LOG ,Global - google.com:80
client.go:541, ERROR ,"Dial failed: dial, lookup $$ on [::1]:53: read udp [::1]:38258->[::1]:53: read: connection refused"
......

Is it because of the -g option or ignore_dns flag?
Thanks for any clue about this.

[binus]

Seems at least we need to do one dns resolve locally, to resolve the upstream cloudfare domain!
maybe the net.ResolveIPAddr doesn't works well in arm :(

[binus]

Solved: net.ResolveIPAddr in arm may query local dns server ( [::1]:53 ), but missing.
Set up manually and all goes well.
BTW: thanks for your useful logg debug tool, which help me alot.

[binus]

More info:
golang/go#10714
golang/go#8877
golang/go#24393
https://stackoverflow.com/questions/38959067/dns-lookup-issue-when-running-my-go-app-in-termux

Fix method 1:
set up local dns server and listen udp:53 , need root.
Fix method 2:
hack go/net to dial higher udp port for dns resolve, to avoid root privilege.
Fix method 3:
use cgo way.
Fix method 4:
use pure go way but change default/fallback behavior.
Fix method 5:
wait for ʕ ◔ϖ◔ʔ (golang) solving this problem ...

EOF

[coyove]

Using cgo is okay to me, otherwise we will have to use some 3rd libs like miekg/dns

[cs8425]

I use some hack & reflect to overwrite defaultNS in net package.
And just work!!

Only test with go version go1.11.5 linux/amd64,
Build with GOOS=linux GOARCH=arm GOARM=7 and GOOS=linux GOARCH=arm64,
On a Android 6.0, kernel 3.10.49, aarch64 CPU phone.

The code:
https://gist.github.com/cs8425/107e01a0652f1f1f6e033b5b68364b5e