badguardhome/dhcpd/helpers.go

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package dhcpd
import (
"fmt"
"log"
"net"
"os"
"path"
"runtime"
"strings"
"github.com/joomcode/errorx"
)
func trace(format string, args ...interface{}) {
pc := make([]uintptr, 10) // at least 1 entry needed
runtime.Callers(2, pc)
f := runtime.FuncForPC(pc[0])
var buf strings.Builder
buf.WriteString(fmt.Sprintf("%s(): ", path.Base(f.Name())))
text := fmt.Sprintf(format, args...)
buf.WriteString(text)
if len(text) == 0 || text[len(text)-1] != '\n' {
buf.WriteRune('\n')
}
fmt.Fprint(os.Stderr, buf.String())
}
func isTimeout(err error) bool {
operr, ok := err.(*net.OpError)
if !ok {
return false
}
return operr.Timeout()
}
// return first IPv4 address of an interface, if there is any
func getIfaceIPv4(iface *net.Interface) *net.IPNet {
ifaceAddrs, err := iface.Addrs()
if err != nil {
panic(err)
}
for _, addr := range ifaceAddrs {
ipnet, ok := addr.(*net.IPNet)
if !ok {
// not an IPNet, should not happen
log.Fatalf("SHOULD NOT HAPPEN: got iface.Addrs() element %s that is not net.IPNet", addr)
}
if ipnet.IP.To4() == nil {
log.Printf("Got IP that is not IPv4: %v", ipnet.IP)
continue
}
log.Printf("Got IP that is IPv4: %v", ipnet.IP)
return &net.IPNet{
IP: ipnet.IP.To4(),
Mask: ipnet.Mask,
}
}
return nil
}
func isConnClosed(err error) bool {
if err == nil {
return false
}
nerr, ok := err.(*net.OpError)
if !ok {
return false
}
if strings.Contains(nerr.Err.Error(), "use of closed network connection") {
return true
}
return false
}
func wrapErrPrint(err error, message string, args ...interface{}) error {
var errx error
if err == nil {
errx = fmt.Errorf(message, args...)
} else {
errx = errorx.Decorate(err, message, args...)
}
log.Println(errx.Error())
return errx
}
func parseIPv4(text string) (net.IP, error) {
result := net.ParseIP(text)
if result == nil {
return nil, fmt.Errorf("%s is not an IP address", text)
}
if result.To4() == nil {
return nil, fmt.Errorf("%s is not an IPv4 address", text)
}
return result.To4(), nil
}