mirror of https://github.com/slackhq/nebula.git
144 lines
3.5 KiB
Go
144 lines
3.5 KiB
Go
package nebula
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import (
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"fmt"
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"math"
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"net"
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"strconv"
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"github.com/slackhq/nebula/cidr"
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"github.com/slackhq/nebula/config"
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"github.com/slackhq/nebula/iputil"
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)
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// This allows us to "guess" what the remote might be for a host while we wait
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// for the lighthouse response. See "lighthouse.calculated_remotes" in the
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// example config file.
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type calculatedRemote struct {
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ipNet net.IPNet
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maskIP iputil.VpnIp
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mask iputil.VpnIp
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port uint32
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}
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func newCalculatedRemote(ipNet *net.IPNet, port int) (*calculatedRemote, error) {
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// Ensure this is an IPv4 mask that we expect
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ones, bits := ipNet.Mask.Size()
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if ones == 0 || bits != 32 {
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return nil, fmt.Errorf("invalid mask: %v", ipNet)
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}
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if port < 0 || port > math.MaxUint16 {
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return nil, fmt.Errorf("invalid port: %d", port)
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}
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return &calculatedRemote{
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ipNet: *ipNet,
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maskIP: iputil.Ip2VpnIp(ipNet.IP),
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mask: iputil.Ip2VpnIp(ipNet.Mask),
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port: uint32(port),
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}, nil
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}
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func (c *calculatedRemote) String() string {
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return fmt.Sprintf("CalculatedRemote(mask=%v port=%d)", c.ipNet, c.port)
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}
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func (c *calculatedRemote) Apply(ip iputil.VpnIp) *Ip4AndPort {
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// Combine the masked bytes of the "mask" IP with the unmasked bytes
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// of the overlay IP
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masked := (c.maskIP & c.mask) | (ip & ^c.mask)
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return &Ip4AndPort{Ip: uint32(masked), Port: c.port}
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}
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func NewCalculatedRemotesFromConfig(c *config.C, k string) (*cidr.Tree4, error) {
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value := c.Get(k)
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if value == nil {
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return nil, nil
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}
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calculatedRemotes := cidr.NewTree4()
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rawMap, ok := value.(map[any]any)
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if !ok {
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return nil, fmt.Errorf("config `%s` has invalid type: %T", k, value)
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}
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for rawKey, rawValue := range rawMap {
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rawCIDR, ok := rawKey.(string)
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if !ok {
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return nil, fmt.Errorf("config `%s` has invalid key (type %T): %v", k, rawKey, rawKey)
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}
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_, ipNet, err := net.ParseCIDR(rawCIDR)
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if err != nil {
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return nil, fmt.Errorf("config `%s` has invalid CIDR: %s", k, rawCIDR)
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}
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entry, err := newCalculatedRemotesListFromConfig(rawValue)
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if err != nil {
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return nil, fmt.Errorf("config '%s.%s': %w", k, rawCIDR, err)
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}
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calculatedRemotes.AddCIDR(ipNet, entry)
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}
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return calculatedRemotes, nil
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}
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func newCalculatedRemotesListFromConfig(raw any) ([]*calculatedRemote, error) {
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rawList, ok := raw.([]any)
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if !ok {
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return nil, fmt.Errorf("calculated_remotes entry has invalid type: %T", raw)
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}
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var l []*calculatedRemote
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for _, e := range rawList {
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c, err := newCalculatedRemotesEntryFromConfig(e)
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if err != nil {
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return nil, fmt.Errorf("calculated_remotes entry: %w", err)
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}
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l = append(l, c)
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}
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return l, nil
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}
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func newCalculatedRemotesEntryFromConfig(raw any) (*calculatedRemote, error) {
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rawMap, ok := raw.(map[any]any)
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if !ok {
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return nil, fmt.Errorf("invalid type: %T", raw)
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}
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rawValue := rawMap["mask"]
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if rawValue == nil {
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return nil, fmt.Errorf("missing mask: %v", rawMap)
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}
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rawMask, ok := rawValue.(string)
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if !ok {
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return nil, fmt.Errorf("invalid mask (type %T): %v", rawValue, rawValue)
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}
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_, ipNet, err := net.ParseCIDR(rawMask)
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if err != nil {
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return nil, fmt.Errorf("invalid mask: %s", rawMask)
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}
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var port int
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rawValue = rawMap["port"]
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if rawValue == nil {
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return nil, fmt.Errorf("missing port: %v", rawMap)
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}
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switch v := rawValue.(type) {
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case int:
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port = v
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case string:
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port, err = strconv.Atoi(v)
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if err != nil {
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return nil, fmt.Errorf("invalid port: %s: %w", v, err)
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}
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default:
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return nil, fmt.Errorf("invalid port (type %T): %v", rawValue, rawValue)
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}
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return newCalculatedRemote(ipNet, port)
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}
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