diff --git a/internal/pmtud/ip/source.go b/internal/pmtud/ip/source.go index 349ff555..8d1c5a2c 100644 --- a/internal/pmtud/ip/source.go +++ b/internal/pmtud/ip/source.go @@ -1,8 +1,10 @@ package ip import ( + "errors" "fmt" "net/netip" + "syscall" "github.com/jsimonetti/rtnetlink" "github.com/qdm12/gluetun/internal/pmtud/constants" @@ -26,7 +28,10 @@ func SrcAddr(dst netip.AddrPort, proto int) (src netip.AddrPort, cleanup func(), return netip.AddrPortFrom(srcAddr, srcPort), cleanup, nil } -var errNoRoute = fmt.Errorf("no route to destination") +var ( + errNoRoute = fmt.Errorf("no route to destination") + ErrNetworkUnreachable = errors.New("network unreachable") +) func srcIP(dst netip.Addr) (netip.Addr, error) { conn, err := rtnetlink.Dial(nil) @@ -49,6 +54,10 @@ func srcIP(dst netip.Addr) (netip.Addr, error) { } messages, err := conn.Route.Get(requestMessage) if err != nil { + var sysErr syscall.Errno + if errors.As(err, &sysErr) && sysErr == syscall.ENETUNREACH { + err = ErrNetworkUnreachable + } return netip.Addr{}, fmt.Errorf("getting routes to %s: %w", dst, err) } diff --git a/internal/pmtud/tcp/mss.go b/internal/pmtud/tcp/mss.go index dbfd6897..a8abe208 100644 --- a/internal/pmtud/tcp/mss.go +++ b/internal/pmtud/tcp/mss.go @@ -43,6 +43,9 @@ func findHighestMSSDestination(ctx context.Context, familyToFD map[int]fileDescr case err != nil: // error already occurred for another findMSS goroutine case errors.Is(result.err, firewall.ErrMarkMatchModuleMissing): err = fmt.Errorf("finding MSS for %s: %w", result.dst, result.err) + case dst.Addr().Is6() && errors.Is(result.err, ip.ErrNetworkUnreachable): + // silently discard IPv6 network unreachable errors since they are common + // and expected when the host doesn't have IPv6 connectivity default: // another error not due to the match module missing logger.Debugf("finding MSS for %s failed: %s", result.dst, result.err) }