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Concern only about flannel ip addresses #1401

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merged 1 commit into from
Mar 9, 2021
Merged

Concern only about flannel ip addresses #1401

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6 changes: 3 additions & 3 deletions backend/ipip/ipip.go
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Original file line number Diff line number Diff line change
Expand Up @@ -88,7 +88,7 @@ func (be *IPIPBackend) RegisterNetwork(ctx context.Context, wg *sync.WaitGroup,
return nil, fmt.Errorf("failed to acquire lease: %v", err)
}

link, err := be.configureIPIPDevice(n.SubnetLease)
link, err := be.configureIPIPDevice(n.SubnetLease, config.Network)

if err != nil {
return nil, err
Expand Down Expand Up @@ -123,7 +123,7 @@ func (be *IPIPBackend) RegisterNetwork(ctx context.Context, wg *sync.WaitGroup,
return n, nil
}

func (be *IPIPBackend) configureIPIPDevice(lease *subnet.Lease) (*netlink.Iptun, error) {
func (be *IPIPBackend) configureIPIPDevice(lease *subnet.Lease, flannelnet ip.IP4Net) (*netlink.Iptun, error) {
// When modprobe ipip module, a tunl0 ipip device is created automatically per network namespace by ipip kernel module.
// It is the namespace default IPIP device with attributes local=any and remote=any.
// When receiving IPIP protocol packets, kernel will forward them to tunl0 as a fallback device
Expand Down Expand Up @@ -195,7 +195,7 @@ func (be *IPIPBackend) configureIPIPDevice(lease *subnet.Lease) (*netlink.Iptun,
// Ensure that the device has a /32 address so that no broadcast routes are created.
// This IP is just used as a source address for host to workload traffic (so
// the return path for the traffic has an address on the flannel network to use as the destination)
if err := ip.EnsureV4AddressOnLink(ip.IP4Net{IP: lease.Subnet.IP, PrefixLen: 32}, link); err != nil {
if err := ip.EnsureV4AddressOnLink(ip.IP4Net{IP: lease.Subnet.IP, PrefixLen: 32}, flannelnet, link); err != nil {
return nil, fmt.Errorf("failed to ensure address of interface %s: %s", link.Attrs().Name, err)
}

Expand Down
4 changes: 2 additions & 2 deletions backend/vxlan/device.go
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Original file line number Diff line number Diff line change
Expand Up @@ -112,8 +112,8 @@ func ensureLink(vxlan *netlink.Vxlan) (*netlink.Vxlan, error) {
return vxlan, nil
}

func (dev *vxlanDevice) Configure(ipn ip.IP4Net) error {
if err := ip.EnsureV4AddressOnLink(ipn, dev.link); err != nil {
func (dev *vxlanDevice) Configure(ipa ip.IP4Net, flannelnet ip.IP4Net) error {
if err := ip.EnsureV4AddressOnLink(ipa, flannelnet, dev.link); err != nil {
return fmt.Errorf("failed to ensure address of interface %s: %s", dev.link.Attrs().Name, err)
}

Expand Down
2 changes: 1 addition & 1 deletion backend/vxlan/vxlan.go
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Original file line number Diff line number Diff line change
Expand Up @@ -155,7 +155,7 @@ func (be *VXLANBackend) RegisterNetwork(ctx context.Context, wg *sync.WaitGroup,
// Ensure that the device has a /32 address so that no broadcast routes are created.
// This IP is just used as a source address for host to workload traffic (so
// the return path for the traffic has an address on the flannel network to use as the destination)
if err := dev.Configure(ip.IP4Net{IP: lease.Subnet.IP, PrefixLen: 32}); err != nil {
if err := dev.Configure(ip.IP4Net{IP: lease.Subnet.IP, PrefixLen: 32}, config.Network); err != nil {
return nil, fmt.Errorf("failed to configure interface %s: %s", dev.link.Attrs().Name, err)
}

Expand Down
32 changes: 17 additions & 15 deletions pkg/ip/iface.go
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@ import (
"syscall"

"github.com/vishvananda/netlink"
log "k8s.io/klog"
)

func getIfaceAddrs(iface *net.Interface) ([]netlink.Addr, error) {
Expand Down Expand Up @@ -131,32 +132,33 @@ func DirectRouting(ip net.IP) (bool, error) {
return false, nil
}

// EnsureV4AddressOnLink ensures that there is only one v4 Addr on `link` and it equals `ipn`.
// If there exist multiple addresses on link, it returns an error message to tell callers to remove additional address.
func EnsureV4AddressOnLink(ipn IP4Net, link netlink.Link) error {
addr := netlink.Addr{IPNet: ipn.ToIPNet()}
// EnsureV4AddressOnLink ensures that there is only one v4 Addr on `link` within the `ipn` address space and it equals `ipa`.
func EnsureV4AddressOnLink(ipa IP4Net, ipn IP4Net, link netlink.Link) error {
addr := netlink.Addr{IPNet: ipa.ToIPNet()}
existingAddrs, err := netlink.AddrList(link, netlink.FAMILY_V4)
if err != nil {
return err
}

// flannel will never make this happen. This situation can only be caused by a user, so get them to sort it out.
if len(existingAddrs) > 1 {
return fmt.Errorf("link has incompatible addresses. Remove additional addresses and try again. %#v", link)
}
var hasAddr bool
for _, existingAddr := range existingAddrs {
if existingAddr.Equal(addr) {
hasAddr = true
continue
}

// If the device has an incompatible address then delete it. This can happen if the lease changes for example.
if len(existingAddrs) == 1 && !existingAddrs[0].Equal(addr) {
if err := netlink.AddrDel(link, &existingAddrs[0]); err != nil {
return fmt.Errorf("failed to remove IP address %s from %s: %s", ipn.String(), link.Attrs().Name, err)
if ipn.Contains(FromIP(existingAddr.IP)) {
if err := netlink.AddrDel(link, &existingAddr); err != nil {
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Can we log this as Info nevertheless? Useful since we are doing kind of a 'destructive' operation.

return fmt.Errorf("failed to remove IP address %s from %s: %s", existingAddr.String(), link.Attrs().Name, err)
}
log.Infof("removed IP address %s from %s", existingAddr.String(), link.Attrs().Name)
}
existingAddrs = []netlink.Addr{}
}

// Actually add the desired address to the interface if needed.
if len(existingAddrs) == 0 {
if !hasAddr {
if err := netlink.AddrAdd(link, &addr); err != nil {
return fmt.Errorf("failed to add IP address %s to %s: %s", ipn.String(), link.Attrs().Name, err)
return fmt.Errorf("failed to add IP address %s to %s: %s", addr.String(), link.Attrs().Name, err)
}
}

Expand Down
18 changes: 13 additions & 5 deletions pkg/ip/iface_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -35,7 +35,8 @@ func TestEnsureV4AddressOnLink(t *testing.T) {
t.Fatal(err)
}
// check changing address
if err := EnsureV4AddressOnLink(IP4Net{IP: FromIP(net.ParseIP("127.0.0.2")), PrefixLen: 24}, lo); err != nil {
ipn := IP4Net{IP: FromIP(net.ParseIP("127.0.0.2")), PrefixLen: 24}
if err := EnsureV4AddressOnLink(ipn, ipn, lo); err != nil {
t.Fatal(err)
}
addrs, err := netlink.AddrList(lo, netlink.FAMILY_V4)
Expand All @@ -46,11 +47,18 @@ func TestEnsureV4AddressOnLink(t *testing.T) {
t.Fatalf("addrs %v is not expected", addrs)
}

// check changing address if there exist multiple addresses
if err := netlink.AddrAdd(lo, &netlink.Addr{IPNet: &net.IPNet{IP: net.ParseIP("127.0.0.3"), Mask: net.CIDRMask(24, 32)}}); err != nil {
// check changing address if there exist unknown addresses
if err := netlink.AddrAdd(lo, &netlink.Addr{IPNet: &net.IPNet{IP: net.ParseIP("127.0.1.1"), Mask: net.CIDRMask(24, 32)}}); err != nil {
t.Fatal(err)
}
if err := EnsureV4AddressOnLink(IP4Net{IP: FromIP(net.ParseIP("127.0.0.2")), PrefixLen: 24}, lo); err == nil {
t.Fatal("EnsureV4AddressOnLink should return error if there exist multiple address on link")
if err := EnsureV4AddressOnLink(ipn, ipn, lo); err != nil {
t.Fatal(err)
}
addrs, err = netlink.AddrList(lo, netlink.FAMILY_V4)
if err != nil {
t.Fatal(err)
}
if len(addrs) != 2 {
t.Fatalf("two addresses expected, addrs: %v", addrs)
}
}