boynux/squid-exporter

package main

import (
    "log"
    "net"
    "strconv"
    "strings"

    "github.com/boynux/squid-exporter/config"

    proxyproto "github.com/pires/go-proxyproto"
)

func createProxyHeader(cfg *config.Config) string {
    la := strings.Split(cfg.ListenAddress, ":")
    if len(la) < 2 {
        log.Printf("Cannot parse listen address (%s). Failed to create proxy header\n", cfg.ListenAddress)
        return ""
    }

    spt, err := strconv.Atoi(la[1])
    if err != nil {
        log.Printf("Failed to create proxy header: %v\n", err.Error())
        return ""
    }

    sip, err := net.LookupIP(la[0])
    if err != nil {
        log.Printf("Failed to create proxy header: %v\n", err.Error())
        return ""
    }

    dip, err := net.LookupIP(cfg.SquidHostname)
    if err != nil {
        log.Printf("Failed to create proxy header: %v\n", err.Error())
        return ""
    }

    ph := &proxyproto.Header{
        Version:           1,
        Command:           proxyproto.PROXY,
        TransportProtocol: proxyproto.TCPv4,
        SourceAddr: &net.TCPAddr{
            IP:   sip[0],
            Port: spt,
        },

        DestinationAddr: &net.TCPAddr{
            IP:   dip[0],
            Port: cfg.SquidPort,
        },
    }
    phs, err := ph.Format()

    if err != nil {
        log.Printf("Failed to create proxy header: %v\n", err.Error())
    }

    // proxyproto adds crlf to the end of the header string, but we will add this later
    // we are triming it here.
    return strings.TrimSuffix(string(phs), "\r\n")
}