mirror of
https://github.com/netbirdio/netbird.git
synced 2026-10-19 11:59:09 +02:00
Riccardo Manfrin
547dd1f177
The Linux network monitor skipped every route update whose Dst was not nil, treating a nil Dst as the default route. Since the bump to vishvananda/netlink v1.3 (v0.43.0) the default route arrives as an explicit 0.0.0.0/0 or ::/0, so every default route change was filtered out and the monitor never fired on Linux, no matter how the underlay moved. Treat both a nil Dst and a zero-length prefix as the default route.
66 lines
1.7 KiB
Go
66 lines
1.7 KiB
Go
//go:build !android
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package networkmonitor
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import (
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"context"
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"errors"
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"fmt"
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"net"
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"syscall"
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log "github.com/sirupsen/logrus"
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"github.com/vishvananda/netlink"
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"github.com/netbirdio/netbird/client/internal/routemanager/systemops"
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)
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func checkChange(ctx context.Context, nexthopv4, nexthopv6 systemops.Nexthop) error {
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if nexthopv4.Intf == nil && nexthopv6.Intf == nil {
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return errors.New("no interfaces available")
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}
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done := make(chan struct{})
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defer close(done)
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routeChan := make(chan netlink.RouteUpdate)
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if err := netlink.RouteSubscribe(routeChan, done); err != nil {
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return fmt.Errorf("subscribe to route updates: %v", err)
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}
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log.Info("Network monitor: started")
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for {
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select {
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case <-ctx.Done():
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return ctx.Err()
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// handle route changes
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case route := <-routeChan:
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// default route and main table
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if !isDefaultRoute(route.Dst) || route.Table != syscall.RT_TABLE_MAIN {
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continue
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}
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switch route.Type {
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// triggered on added/replaced routes
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case syscall.RTM_NEWROUTE:
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log.Infof("Network monitor: default route changed: via %s, interface %d", route.Gw, route.LinkIndex)
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return nil
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case syscall.RTM_DELROUTE:
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if nexthopv4.Intf != nil && route.Gw.Equal(nexthopv4.IP.AsSlice()) || nexthopv6.Intf != nil && route.Gw.Equal(nexthopv6.IP.AsSlice()) {
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log.Infof("Network monitor: default route removed: via %s, interface %d", route.Gw, route.LinkIndex)
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return nil
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}
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}
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}
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}
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}
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// isDefaultRoute reports whether dst is a default route. netlink v1.3 reports
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// the default as 0.0.0.0/0 or ::/0, older versions as a nil Dst.
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func isDefaultRoute(dst *net.IPNet) bool {
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if dst == nil {
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return true
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}
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ones, _ := dst.Mask.Size()
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return ones == 0
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}
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