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feat: support via gateway for v6 multihop for v4 routes (#1521)
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Co-authored-by: Nate Brown <nbrown.us@gmail.com>
This commit is contained in:
Bryan Lee 2025-11-19 20:21:03 -08:00 • committed by GitHub
parent a5ee928990
commit 12cf348c80
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GPG key ID: B5690EEEBB952194
1 changed files with 38 additions and 27 deletions
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65
overlay/tun_linux.go
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@ -586,48 +586,42 @@ func (t *tun) isGatewayInVpnNetworks(gwAddr netip.Addr) bool {
}
func (t *tun) getGatewaysFromRoute(r *netlink.Route) routing.Gateways {
var gateways routing.Gateways
link, err := netlink.LinkByName(t.Device)
if err != nil {
t.l.WithField("Devicename", t.Device).Error("Ignoring route update: failed to get link by name")
t.l.WithField("deviceName", t.Device).Error("Ignoring route update: failed to get link by name")
return gateways
}
// If this route is relevant to our interface and there is a gateway then add it
if r.LinkIndex == link.Attrs().Index && len(r.Gw) > 0 {
gwAddr, ok := netip.AddrFromSlice(r.Gw)
if !ok {
t.l.WithField("route", r).Debug("Ignoring route update, invalid gateway address")
} else {
gwAddr = gwAddr.Unmap()
if !t.isGatewayInVpnNetworks(gwAddr) {
// Gateway isn't in our overlay network, ignore
t.l.WithField("route", r).Debug("Ignoring route update, not in our network")
} else {
if r.LinkIndex == link.Attrs().Index {
gwAddr, ok := getGatewayAddr(r.Gw, r.Via)
if ok {
if t.isGatewayInVpnNetworks(gwAddr) {
gateways = append(gateways, routing.NewGateway(gwAddr, 1))
} else {
// Gateway isn't in our overlay network, ignore
t.l.WithField("route", r).Debug("Ignoring route update, gateway is not in our network")
}
} else {
t.l.WithField("route", r).Debug("Ignoring route update, invalid gateway or via address")
}
}
for _, p := range r.MultiPath {
// If this route is relevant to our interface and there is a gateway then add it
if p.LinkIndex == link.Attrs().Index && len(p.Gw) > 0 {
gwAddr, ok := netip.AddrFromSlice(p.Gw)
if !ok {
t.l.WithField("route", r).Debug("Ignoring multipath route update, invalid gateway address")
} else {
gwAddr = gwAddr.Unmap()
if !t.isGatewayInVpnNetworks(gwAddr) {
// Gateway isn't in our overlay network, ignore
t.l.WithField("route", r).Debug("Ignoring route update, not in our network")
} else {
// p.Hops+1 = weight of the route
if p.LinkIndex == link.Attrs().Index {
gwAddr, ok := getGatewayAddr(p.Gw, p.Via)
if ok {
if t.isGatewayInVpnNetworks(gwAddr) {
gateways = append(gateways, routing.NewGateway(gwAddr, p.Hops+1))
} else {
// Gateway isn't in our overlay network, ignore
t.l.WithField("route", r).Debug("Ignoring route update, gateway is not in our network")
}
} else {
t.l.WithField("route", r).Debug("Ignoring route update, invalid gateway or via address")
}
}
}
@ -636,10 +630,27 @@ func (t *tun) getGatewaysFromRoute(r *netlink.Route) routing.Gateways {
return gateways
}
func getGatewayAddr(gw net.IP, via netlink.Destination) (netip.Addr, bool) {
// Try to use the old RTA_GATEWAY first
gwAddr, ok := netip.AddrFromSlice(gw)
if !ok {
// Fallback to the new RTA_VIA
rVia, ok := via.(*netlink.Via)
if ok {
gwAddr, ok = netip.AddrFromSlice(rVia.Addr)
}
}
if gwAddr.IsValid() {
gwAddr = gwAddr.Unmap()
return gwAddr, true
}
return netip.Addr{}, false
}
func (t *tun) updateRoutes(r netlink.RouteUpdate) {
gateways := t.getGatewaysFromRoute(&r.Route)
if len(gateways) == 0 {
// No gateways relevant to our network, no routing changes required.
t.l.WithField("route", r).Debug("Ignoring route update, no gateways")