Monitor network changes and restart engine on detection (#1904)

client/internal/routemanager/systemops_bsd.go

@@ -3,10 +3,11 @@
 package routemanager
 
 import (
+	"errors"
 	"fmt"
 	"net"
 	"net/netip"
-	"errors"
+	"strconv"
 	"syscall"
 	"time"
 
@@ -15,17 +16,22 @@ import (
 	"golang.org/x/net/route"
 )
 
+type Route struct {
+	Dst       netip.Prefix
+	Gw        netip.Addr
+	Interface *net.Interface
+}
 
-// TODO: fix here with retry and backoff
 func getRoutesFromTable() ([]netip.Prefix, error) {
 	tab, err := retryFetchRIB()
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("fetch RIB: %v", err)
 	}
 	msgs, err := route.ParseRIB(route.RIBTypeRoute, tab)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("parse RIB: %v", err)
 	}
+
 	var prefixList []netip.Prefix
 	for _, msg := range msgs {
 		m := msg.(*route.RouteMessage)
@@ -33,7 +39,7 @@ func getRoutesFromTable() ([]netip.Prefix, error) {
 		if m.Version < 3 || m.Version > 5 {
 			return nil, fmt.Errorf("unexpected RIB message version: %d", m.Version)
 		}
-		if m.Type != 4 /* RTM_GET */ {
+		if m.Type != syscall.RTM_GET {
 			return nil, fmt.Errorf("unexpected RIB message type: %d", m.Type)
 		}
 
@@ -42,28 +48,13 @@ func getRoutesFromTable() ([]netip.Prefix, error) {
 			continue
 		}
 
-		if len(m.Addrs) < 3 {
-			log.Warnf("Unexpected RIB message Addrs: %v", m.Addrs)
+		route, err := MsgToRoute(m)
+		if err != nil {
+			log.Warnf("Failed to parse route message: %v", err)
 			continue
 		}
-
-		addr, ok := toNetIPAddr(m.Addrs[0])
-		if !ok {
-			continue
-		}
-
-		cidr := 32
-		if mask := m.Addrs[2]; mask != nil {
-			cidr, ok = toCIDR(mask)
-			if !ok {
-				log.Debugf("Unexpected RIB message Addrs[2]: %v", mask)
-				continue
-			}
-		}
-
-		routePrefix := netip.PrefixFrom(addr, cidr)
-		if routePrefix.IsValid() {
-			prefixList = append(prefixList, routePrefix)
+		if route.Dst.IsValid() {
+			prefixList = append(prefixList, route.Dst)
 		}
 	}
 	return prefixList, nil
@@ -75,7 +66,7 @@ func retryFetchRIB() ([]byte, error) {
 		var err error
 		out, err = route.FetchRIB(syscall.AF_UNSPEC, route.RIBTypeRoute, 0)
 		if errors.Is(err, syscall.ENOMEM) {
-			log.Debug("retrying fetchRIB due to 'cannot allocate memory' error")
+			log.Debug("~etrying fetchRIB due to 'cannot allocate memory' error")
 			return err
 		} else if err != nil {
 			return backoff.Permanent(err)
@@ -95,22 +86,74 @@ func retryFetchRIB() ([]byte, error) {
 	return out, nil
 }
 
-func toNetIPAddr(a route.Addr) (netip.Addr, bool) {
+func toNetIP(a route.Addr) netip.Addr {
 	switch t := a.(type) {
 	case *route.Inet4Addr:
-		return netip.AddrFrom4(t.IP), true
+		return netip.AddrFrom4(t.IP)
+	case *route.Inet6Addr:
+		ip := netip.AddrFrom16(t.IP)
+		if t.ZoneID != 0 {
+			ip.WithZone(strconv.Itoa(t.ZoneID))
+		}
+		return ip
 	default:
-		return netip.Addr{}, false
+		return netip.Addr{}
 	}
 }
 
-func toCIDR(a route.Addr) (int, bool) {
+func ones(a route.Addr) (int, error) {
 	switch t := a.(type) {
 	case *route.Inet4Addr:
-		mask := net.IPv4Mask(t.IP[0], t.IP[1], t.IP[2], t.IP[3])
-		cidr, _ := mask.Size()
-		return cidr, true
+		mask, _ := net.IPMask(t.IP[:]).Size()
+		return mask, nil
+	case *route.Inet6Addr:
+		mask, _ := net.IPMask(t.IP[:]).Size()
+		return mask, nil
 	default:
-		return 0, false
+		return 0, fmt.Errorf("unexpected address type: %T", a)
 	}
 }
+
+func MsgToRoute(msg *route.RouteMessage) (*Route, error) {
+	dstIP, nexthop, dstMask := msg.Addrs[0], msg.Addrs[1], msg.Addrs[2]
+
+	addr := toNetIP(dstIP)
+
+	var nexthopAddr netip.Addr
+	var nexthopIntf *net.Interface
+
+	switch t := nexthop.(type) {
+	case *route.Inet4Addr, *route.Inet6Addr:
+		nexthopAddr = toNetIP(t)
+	case *route.LinkAddr:
+		nexthopIntf = &net.Interface{
+			Index: t.Index,
+			Name:  t.Name,
+		}
+	default:
+		return nil, fmt.Errorf("unexpected next hop type: %T", t)
+	}
+
+	var prefix netip.Prefix
+
+	if dstMask == nil {
+		if addr.Is4() {
+			prefix = netip.PrefixFrom(addr, 32)
+		} else {
+			prefix = netip.PrefixFrom(addr, 128)
+		}
+	} else {
+		bits, err := ones(dstMask)
+		if err != nil {
+			return nil, fmt.Errorf("failed to parse mask: %v", dstMask)
+		}
+		prefix = netip.PrefixFrom(addr, bits)
+	}
+
+	return &Route{
+		Dst:       prefix,
+		Gw:        nexthopAddr,
+		Interface: nexthopIntf,
+	}, nil
+
+}