Hi I found 2 problems

[sanguohot]

1.It may create many new connections and override the older in high concurrency
f.connectionsMutex.Lock()
f.connections[addr.String()] = connection{
udp: conn,
lastActive: time.Now(),
}
f.connectionsMutex.Unlock()
I think you should change to
f.connectionsMutex.Lock()
if _, found := f.connections[addr.String()]; !found {
f.connections[addr.String()] = connection{
udp: conn,
lastActive: time.Now(),
}
}
f.connectionsMutex.Unlock()
2.HTTP over udp proxy does not work,but command and heatbeat packets are good.this may be a problem, because my client works well when connected to server directly，but found missing page when past through the proxy,and I tested with just only a client.I am really puzzled about it.Any help would be greatly appreciated!

[1lann]

Hey, sorry I'm getting back to this so late! Thanks for your reports. To be honest I don't really use this because I couldn't get it to work properly as well (lol) so I ended up using socat instead. However I do actually want it to work, so I'll take a look into it.

I agree with your first problem, that is a race condition. I'll fix that when I have time (or you can submit a PR if you'd like).

The second problem I'm not sure about, I think I encountered the same problem before, I think it's just caused by me not copying the UDP headers correctly or something along those lines? Not sure, I'll mess around with it.

[winguse]

FYI: I find the same problem and write my own implementation: https://github.com/winguse/udp-xor

[1lann]

Oh I see now, my code is really silly, I wasn't as accustomed to writing network code in Go a few years ago, but now I am. It's likely because I'm not using WriteMsgUDP/ReadMsgUDP, so Go might automatically batch packets together when it shouldn't.

@winguse You use that presumably to chain hop beyond the great firewall of China right? I'm in China right now (and every time I come to China I experiment with different solutions to get around the GFW) and I've found the best solution is to encapsulate traffic with kcp/kcptun: https://github.com/xtaci/kcptun, which gets around the massive packet loss when getting past the firewall, as KCP re-transmits very quickly and frequently. Just thought I might let you know.

[winguse]

thanks @1lann , I know KCP and it's very helpful.