[Bug] tproxy:// fails to proccess IPv6 connections

[phantomcraft]

Easy to reproduce:

ip netns add nsx
ip li add vethx type veth peer name peerx netns nsx
ip li set vethx up
ip -6 addr add fd00::1/64 dev vethx
ip netns exec nsx ip li set lo up
ip netns exec nsx ip li set peerx up
ip -6 netns exec nsx ip addr add fd00::2/64 dev peerx
ip netns exec nsx ip -6 route add default via fd00::1 dev peerx

ip -6 rule add fwmark 1088 table 100
ip -6 route add local default dev vethx table 100

ip6tables -t mangle -A PREROUTING -i vethx -p udp -j TPROXY -s fd00::2 --on-ip fd00::1 --on-port 10000 --tproxy-mark 1088

============================================

root@localhost:/home/user# glider -verbose -listen tproxy://[fd00::1]:10000 -forward socks5://127.0.0.1:9000
2021/10/11 21:38:25 group.go:186: [group] only 1 forwarder found, disable health checking
2021/10/11 21:38:25 server.go:78: [tproxyu] listening UDP on [fd00::1]:10000
2021/10/11 21:38:25 server.go:78: [tproxyu] listening UDP on 10.0.0.1:10000
2021/10/11 21:39:00 server.go:84: [tproxyu] read error: unable to obtain original destination: %!s(<nil>)
2021/10/11 21:39:05 server.go:84: [tproxyu] read error: unable to obtain original destination: %!s(<nil>)
2021/10/11 21:39:10 server.go:84: [tproxyu] read error: unable to obtain original destination: %!s(<nil>)

=============================================

root@localhost:/home/user# ip netns exec nsx dig @2606:4700:4700::1111 g.co
; <<>> DiG 9.16.15-Debian <<>> @2606:4700:4700::1111 g.co
; (1 server found)
;; global options: +cmd
;; connection timed out; no servers could be reached

[phantomcraft]

This other issue is related to IPv6 too: #291

I will compile and test later to see if your commit solved the provbem.

[github-actions]

This issue is stale because it has been open 90 days with no activity. Remove stale label or comment or this will be closed in 5 days.

[phantomcraft]

@nadoo

I tested here, it not works yet:

root@localhost:/home/user# glider -verbose -listen tproxy://[fd00::1]:10000 -forward socks5://127.0.0.1:9000
2022/01/20 21:56:25 group.go:191: [group] main: only 1 forwarder found, disable health checking
2022/01/20 21:56:25 server.go:78: [tproxyu] listening UDP on [fd00::1]:10000
2022/01/20 21:56:35 server.go:84: [tproxyu] read error: unable to obtain original destination: %!s(<nil>)
2022/01/20 21:56:40 server.go:84: [tproxyu] read error: unable to obtain original destination: %!s(<nil>)
2022/01/20 21:56:45 server.go:84: [tproxyu] read error: unable to obtain original destination: %!s(<nil>)

root@localhost:/home/user# ip netns exec nsx dig @2606:4700:4700::1111 g.co

; <<>> DiG 9.17.21-1-Debian <<>> @2606:4700:4700::1111 g.co
; (1 server found)
;; global options: +cmd
;; connection timed out; no servers could be reached

[nadoo]

Hi @phantomcraft , you can try the attachment to see whether it fixed..
glider-dev-linux-amd64.zip

[phantomcraft]

Not yet:

root@localhost:/home/user# /dev/shm/glider -verbose -listen tproxy://[fd00::1]:10000 -forward socks5://127.0.0.1:9000
2022/01/24 15:53:15 group.go:191: [group] main: only 1 forwarder found, disable health checking
2022/01/24 15:53:15 server.go:78: [tproxyu] listening UDP on [fd00::1]:10000
2022/01/24 15:53:31 server.go:84: [tproxyu] read error: unable to obtain original destination: %!s(<nil>)
2022/01/24 15:53:36 server.go:84: [tproxyu] read error: unable to obtain original destination: %!s(<nil>)
2022/01/24 15:53:41 server.go:84: [tproxyu] read error: unable to obtain original destination: %!s(<nil>)

root@localhost:/home/user# ip netns exec nsx dig @2606:4700:4700::1111 g.co
; <<>> DiG 9.17.21-1-Debian <<>> @2606:4700:4700::1111 g.co
; (1 server found)
;; global options: +cmd
;; connection timed out; no servers could be reached

[nadoo]

Sorry, now it should be fixed.
glider-dev-linux-amd64.zip

[phantomcraft]

@nadoo

I believe now it works:

root@localhost:/home/user# /dev/shm/glider -verbose -listen tproxy://[fd00::1]:10000 -forward socks5://127.0.0.1:9000
2022/01/25 19:07:22 group.go:191: [group] main: only 1 forwarder found, disable health checking
2022/01/25 19:07:22 server.go:78: [tproxyu] listening UDP on [fd00::1]:10000
2022/01/25 19:07:46 server.go:108: [tproxyu] dial to [2606:4700:4700::1111]:53 error: proxy: failed to read greeting from SOCKS5 proxy at 127.0.0.1:9000: EOF
2022/01/25 19:07:50 server.go:108: [tproxyu] dial to [2606:4700:4700::1111]:53 error: proxy: failed to read greeting from SOCKS5 proxy at 127.0.0.1:9000: EOF
2022/01/25 19:07:56 server.go:108: [tproxyu] dial to [2606:4700:4700::1111]:53 error: proxy: failed to read greeting from SOCKS5 proxy at 127.0.0.1:9000: EOF

root@localhost:/home/user# ip netns exec nsx dig @2606:4700:4700::1111 g.co
; <<>> DiG 9.17.21-1-Debian <<>> @2606:4700:4700::1111 g.co
; (1 server found)
;; global options: +cmd
;; connection timed out; no servers could be reached

Sorry, I don't have IPv6 connectivity at the moment, all that I can see is that the connection reached Glider. I think this is enough.

If this resolves this issue, you can close it.

[nadoo]

Thanks for your testing! Feel free to reopen this issue when there's still any problem.