CODEWITHSUNDEEP
govpnpptp
yh_like_programing
yh_like_programing

Reputation: 19

How to use VPN(pptp) with golang net package?

I've bound several vpn on the server which is ppp0 ~ ppp4. Now comes the problem.I want to start 5 progresses each one use the difference network interface.
proc0 -> ppp0
proc1 -> ppp1
proc2 -> ppp2
proc3 -> ppp3
proc4 -> ppp4
I now how to do this with c language.Just use setsockopt with parameter SO_BINDTODEVICE. But how to do this with net package in golang?

Upvotes: 0

Views: 3533

Answers (2)

Mitch Li
Mitch Li

Reputation: 1

The dialer's LocalAddr doesn't work for ppp interfaces, we should set the SOL_SOCKET flag to socket using setsockopt, for go 1.11+ you can create a dialer like this

    dialer := net.Dialer{
        Control: func(network, address string, c syscall.RawConn) error {
            return c.Control(func(fd uintptr) {
                err := syscall.SetsockoptString(int(fd), syscall.SOL_SOCKET, 25, "ppp0")
                if err != nil {
                    log.Printf("control: %s", err)
                    return
                }
            })
        },
    }
    // use the dialer

Upvotes: 0

Intermernet
Intermernet

Reputation: 19418

You probably want net.Interfaces() to get a slice of net.Interface() representing the network interfaces on your system, or, as you know the interface names, you can use net.InterfaceByName() to get a particular net.Interface.

ppp0, err := net.InterfaceByName("ppp0")

You can then call Interface.Addrs() on the returned net.Interface and get the interface's IP address(es).

addrs, err := ppp0.Addrs()

You can then use the desired address in the rest of your code (probably using net.ListenIP or net.DialIP.

addr, err := net.ResolveIPAddr("ip4", addrs[0])
// check err
conn, err := net.ListenIP("ip4:pptp", addr)
// check err, then do stuff with conn

Regarding doing this for more than one interface concurrently, you can launch a goroutine for each listener / interface, and move the traffic over channels, but this really depends on what you want to do. (are you just logging the data, sending the data, modifying the data etc.)

Upvotes: 1

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