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f309b120cd
* Retry reading routing table (bsd) Similar to #1817, BSD base OSes will return "cannot allocate memory" errors when routing table is expanding.
117 lines
2.5 KiB
Go
117 lines
2.5 KiB
Go
//go:build darwin || dragonfly || freebsd || netbsd || openbsd
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package routemanager
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import (
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"fmt"
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"net"
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"net/netip"
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"errors"
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"syscall"
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"time"
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"github.com/cenkalti/backoff/v4"
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log "github.com/sirupsen/logrus"
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"golang.org/x/net/route"
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)
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// TODO: fix here with retry and backoff
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func getRoutesFromTable() ([]netip.Prefix, error) {
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tab, err := retryFetchRIB()
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if err != nil {
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return nil, err
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}
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msgs, err := route.ParseRIB(route.RIBTypeRoute, tab)
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if err != nil {
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return nil, err
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}
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var prefixList []netip.Prefix
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for _, msg := range msgs {
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m := msg.(*route.RouteMessage)
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if m.Version < 3 || m.Version > 5 {
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return nil, fmt.Errorf("unexpected RIB message version: %d", m.Version)
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}
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if m.Type != 4 /* RTM_GET */ {
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return nil, fmt.Errorf("unexpected RIB message type: %d", m.Type)
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}
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if m.Flags&syscall.RTF_UP == 0 ||
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m.Flags&(syscall.RTF_REJECT|syscall.RTF_BLACKHOLE|syscall.RTF_WASCLONED) != 0 {
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continue
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}
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if len(m.Addrs) < 3 {
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log.Warnf("Unexpected RIB message Addrs: %v", m.Addrs)
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continue
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}
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addr, ok := toNetIPAddr(m.Addrs[0])
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if !ok {
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continue
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}
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cidr := 32
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if mask := m.Addrs[2]; mask != nil {
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cidr, ok = toCIDR(mask)
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if !ok {
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log.Debugf("Unexpected RIB message Addrs[2]: %v", mask)
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continue
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}
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}
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routePrefix := netip.PrefixFrom(addr, cidr)
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if routePrefix.IsValid() {
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prefixList = append(prefixList, routePrefix)
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}
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}
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return prefixList, nil
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}
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func retryFetchRIB() ([]byte, error) {
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var out []byte
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operation := func() error {
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var err error
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out, err = route.FetchRIB(syscall.AF_UNSPEC, route.RIBTypeRoute, 0)
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if errors.Is(err, syscall.ENOMEM) {
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log.Debug("retrying fetchRIB due to 'cannot allocate memory' error")
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return err
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} else if err != nil {
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return backoff.Permanent(err)
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}
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return nil
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}
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expBackOff := backoff.NewExponentialBackOff()
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expBackOff.InitialInterval = 50 * time.Millisecond
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expBackOff.MaxInterval = 500 * time.Millisecond
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expBackOff.MaxElapsedTime = 1 * time.Second
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err := backoff.Retry(operation, expBackOff)
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if err != nil {
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return nil, fmt.Errorf("failed to fetch routing information: %w", err)
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}
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return out, nil
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}
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func toNetIPAddr(a route.Addr) (netip.Addr, bool) {
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switch t := a.(type) {
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case *route.Inet4Addr:
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return netip.AddrFrom4(t.IP), true
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default:
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return netip.Addr{}, false
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}
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}
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func toCIDR(a route.Addr) (int, bool) {
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switch t := a.(type) {
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case *route.Inet4Addr:
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mask := net.IPv4Mask(t.IP[0], t.IP[1], t.IP[2], t.IP[3])
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cidr, _ := mask.Size()
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return cidr, true
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default:
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return 0, false
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}
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}
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