mirror of
https://github.com/netbirdio/netbird.git
synced 2024-12-12 09:50:47 +01:00
96 lines
2.4 KiB
Go
96 lines
2.4 KiB
Go
//go:build (darwin && !ios) || dragonfly || freebsd || netbsd || openbsd
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package networkmonitor
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import (
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"context"
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"fmt"
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"syscall"
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"unsafe"
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log "github.com/sirupsen/logrus"
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"golang.org/x/net/route"
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"golang.org/x/sys/unix"
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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, callback func()) error {
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fd, err := unix.Socket(syscall.AF_ROUTE, syscall.SOCK_RAW, syscall.AF_UNSPEC)
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if err != nil {
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return fmt.Errorf("failed to open routing socket: %v", err)
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}
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defer func() {
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if err := unix.Close(fd); err != nil {
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log.Errorf("Network monitor: failed to close routing socket: %v", err)
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}
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}()
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for {
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select {
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case <-ctx.Done():
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return ErrStopped
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default:
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buf := make([]byte, 2048)
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n, err := unix.Read(fd, buf)
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if err != nil {
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log.Errorf("Network monitor: failed to read from routing socket: %v", err)
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continue
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}
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if n < unix.SizeofRtMsghdr {
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log.Errorf("Network monitor: read from routing socket returned less than expected: %d bytes", n)
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continue
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}
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msg := (*unix.RtMsghdr)(unsafe.Pointer(&buf[0]))
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switch msg.Type {
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// handle route changes
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case unix.RTM_ADD, syscall.RTM_DELETE:
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route, err := parseRouteMessage(buf[:n])
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if err != nil {
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log.Errorf("Network monitor: error parsing routing message: %v", err)
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continue
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}
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if !route.Dst.Addr().IsUnspecified() {
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continue
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}
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intf := "<nil>"
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if route.Interface != nil {
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intf = route.Interface.Name
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}
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switch msg.Type {
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case unix.RTM_ADD:
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log.Infof("Network monitor: default route changed: via %s, interface %s", route.Gw, intf)
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go callback()
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case unix.RTM_DELETE:
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if nexthopv4.Intf != nil && route.Gw.Compare(nexthopv4.IP) == 0 || nexthopv6.Intf != nil && route.Gw.Compare(nexthopv6.IP) == 0 {
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log.Infof("Network monitor: default route removed: via %s, interface %s", route.Gw, intf)
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go callback()
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}
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}
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}
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}
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}
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}
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func parseRouteMessage(buf []byte) (*systemops.Route, error) {
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msgs, err := route.ParseRIB(route.RIBTypeRoute, buf)
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if err != nil {
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return nil, fmt.Errorf("parse RIB: %v", err)
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}
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if len(msgs) != 1 {
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return nil, fmt.Errorf("unexpected RIB message msgs: %v", msgs)
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}
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msg, ok := msgs[0].(*route.RouteMessage)
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if !ok {
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return nil, fmt.Errorf("unexpected RIB message type: %T", msgs[0])
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}
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return systemops.MsgToRoute(msg)
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}
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