Problem running on a router

[Migel1]

I tried to run wireproxy on a router.
To achieve this I crosscompiled source code for ARM Linux (GOOS=linux GOARCH=arm GOARM=5) and run the resulting WireProxy binary on the router.

The binary started successfully, but when I tried to connect to the proxy I got the following error on the router console:

DEBUG: 2024/12/16 17:51:42 peer(bmXO…fgyo) - Sending handshake initiation
ERROR: 2024/12/16 17:51:42 peer(bmXO…fgyo) - Failed to send handshake initiation: write udp 0.0.0.0:61895: sendmmsg: function not implemented

The kernel version on router is Linux router 2.6.36.4brcmarm #82 PREEMPT Wed Aug 7 09:46:26 CEST 2024 armv7l Tomato.

I this Linux kernel supported? Or may be I need to add some special options to run wireproxy on a router?

[artem-russkikh]

I didn't attempt to run wireproxy on a router. Need to research this topic. Meanwhile you can search for similar issues in the origin wireguard GitHub repository at https://github.com/pufferffish/wireproxy

[Migel1]

It seems that the gvisor library uses the sendmmsg Linux system call, which is available only in Linux kernels 3.0+ :(

[ValentineShilov]

In Amnezia-wg I fixed the same problem by changing conn/bind_std.go.
In func (s *StdNetBind) send(conn net.UDPConn, pc batchWriter, msgs []ipv6.Message)
by default for Linux WriteBatch is used to send udp packets (and it uses syscall absent on kernel 2.)
change the code

var (
		n     int
		err   error
		start int
	)
if runtime.GOOS == "linux" || runtime.GOOS == "android" {
		for {
			n, err = pc.WriteBatch(msgs[start:], 0)
			if err != nil || n == len(msgs[start:]) {
				break
			}
			start += n
		}
	} else {
		for _, msg := range msgs {
			_, _, err = conn.WriteMsgUDP(msg.Buffers[0], msg.OOB, msg.Addr.(*net.UDPAddr))
			if err != nil {
				break
			}
		}
	}

to

var (
err   error
)
      for _, msg := range msgs {
	      _, _, err = conn.WriteMsgUDP(msg.Buffers[0], msg.OOB, msg.Addr.(*net.UDPAddr))
	      if err != nil {
		      break
	      }
		
	}