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fix(routing): VPNLocalGatewayIP Wireguard support

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This commit is contained in:
Quentin McGaw
2023-06-28 14:23:34 +00:00
parent 2873b06275
commit 76a92b90e3
1 changed files with 26 additions and 8 deletions
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34
internal/routing/vpn.go
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@@ -6,27 +6,45 @@ import (
"net/netip" "net/netip"
"github.com/qdm12/gluetun/internal/netlink" "github.com/qdm12/gluetun/internal/netlink"
"golang.org/x/sys/unix"
) )
var ( var (
ErrVPNLocalGatewayIPNotFound = errors.New("VPN local gateway IP address not found") ErrVPNLocalGatewayIPNotFound = errors.New("VPN local gateway IP address not found")
ErrVPNLocalGatewayIPv6NotSupported = errors.New("VPN local gateway IPv6 address not supported")
) )
func (r *Routing) VPNLocalGatewayIP(vpnIntf string) (ip netip.Addr, err error) { func (r *Routing) VPNLocalGatewayIP(vpnIntf string) (ip netip.Addr, err error) {
vpnLink, err := r.netLinker.LinkByName(vpnIntf)
if err != nil {
return ip, fmt.Errorf("finding link %s: %w", vpnIntf, err)
}
vpnLinkIndex := vpnLink.Index
routes, err := r.netLinker.RouteList(netlink.FamilyAll) routes, err := r.netLinker.RouteList(netlink.FamilyAll)
if err != nil { if err != nil {
return ip, fmt.Errorf("listing routes: %w", err) return ip, fmt.Errorf("listing routes: %w", err)
} }
for _, route := range routes { for _, route := range routes {
link, err := r.netLinker.LinkByIndex(route.LinkIndex) if route.LinkIndex != vpnLinkIndex {
if err != nil { continue
return ip, fmt.Errorf("finding link at index %d: %w", route.LinkIndex, err)
} }
interfaceName := link.Name
if interfaceName == vpnIntf && switch {
route.Dst.IsValid() && case route.Dst.IsValid() && route.Dst.Addr().IsUnspecified(): // OpenVPN
route.Dst.Addr().IsUnspecified() {
return route.Gw, nil return route.Gw, nil
case route.Dst.IsSingleIP() &&
route.Dst.Addr().Compare(route.Src) == 0 &&
route.Table == unix.RT_TABLE_LOCAL: // Wireguard
route.Src = route.Src.Unmap()
if route.Src.Is6() {
return netip.Addr{}, fmt.Errorf("%w: %s", ErrVPNLocalGatewayIPv6NotSupported, route.Src)
}
bytes := route.Src.As4()
// force last byte to 1 to get the VPN gateway IP
// This is not necessarily bullet proof but it seems to work.
bytes[3] = 1
return netip.AddrFrom4(bytes), nil
} }
} }
return ip, fmt.Errorf("%w: in %d routes", ErrVPNLocalGatewayIPNotFound, len(routes)) return ip, fmt.Errorf("%w: in %d routes", ErrVPNLocalGatewayIPNotFound, len(routes))