mirror of
https://github.com/slackhq/nebula.git
synced 2025-11-22 08:24:25 +01:00
124 lines
3.1 KiB
Go
124 lines
3.1 KiB
Go
package overlay
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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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"github.com/sirupsen/logrus"
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"github.com/slackhq/nebula/config"
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"github.com/slackhq/nebula/util"
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)
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const DefaultMTU = 1300
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const VirtioNetHdrLen = 10 // Size of virtio_net_hdr structure
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// TODO: We may be able to remove routines
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type DeviceFactory func(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, routines int) (Device, error)
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func NewDeviceFromConfig(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, routines int) (Device, error) {
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switch {
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case c.GetBool("tun.disabled", false):
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tun := newDisabledTun(vpnNetworks, c.GetInt("tun.tx_queue", 500), c.GetBool("stats.message_metrics", false), l)
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return tun, nil
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default:
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return newTun(c, l, vpnNetworks, routines > 1)
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}
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}
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func NewFdDeviceFromConfig(fd *int) DeviceFactory {
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return func(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, routines int) (Device, error) {
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return newTunFromFd(c, l, *fd, vpnNetworks)
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}
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}
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func getAllRoutesFromConfig(c *config.C, vpnNetworks []netip.Prefix, initial bool) (bool, []Route, error) {
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if !initial && !c.HasChanged("tun.routes") && !c.HasChanged("tun.unsafe_routes") {
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return false, nil, nil
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}
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routes, err := parseRoutes(c, vpnNetworks)
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if err != nil {
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return true, nil, util.NewContextualError("Could not parse tun.routes", nil, err)
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}
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unsafeRoutes, err := parseUnsafeRoutes(c, vpnNetworks)
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if err != nil {
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return true, nil, util.NewContextualError("Could not parse tun.unsafe_routes", nil, err)
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}
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routes = append(routes, unsafeRoutes...)
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return true, routes, nil
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}
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// findRemovedRoutes will return all routes that are not present in the newRoutes list and would affect the system route table.
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// Via is not used to evaluate since it does not affect the system route table.
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func findRemovedRoutes(newRoutes, oldRoutes []Route) []Route {
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var removed []Route
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has := func(entry Route) bool {
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for _, check := range newRoutes {
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if check.Equal(entry) {
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return true
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}
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}
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return false
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}
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for _, oldEntry := range oldRoutes {
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if !has(oldEntry) {
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removed = append(removed, oldEntry)
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}
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}
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return removed
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}
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func prefixToMask(prefix netip.Prefix) netip.Addr {
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pLen := 128
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if prefix.Addr().Is4() {
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pLen = 32
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}
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addr, _ := netip.AddrFromSlice(net.CIDRMask(prefix.Bits(), pLen))
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return addr
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}
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func flipBytes(b []byte) []byte {
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for i := 0; i < len(b); i++ {
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b[i] ^= 0xFF
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}
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return b
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}
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func orBytes(a []byte, b []byte) []byte {
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ret := make([]byte, len(a))
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for i := 0; i < len(a); i++ {
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ret[i] = a[i] | b[i]
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}
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return ret
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}
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func getBroadcast(cidr netip.Prefix) netip.Addr {
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broadcast, _ := netip.AddrFromSlice(
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orBytes(
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cidr.Addr().AsSlice(),
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flipBytes(prefixToMask(cidr).AsSlice()),
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),
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)
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return broadcast
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}
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func selectGateway(dest netip.Prefix, gateways []netip.Prefix) (netip.Prefix, error) {
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for _, gateway := range gateways {
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if dest.Addr().Is4() && gateway.Addr().Is4() {
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return gateway, nil
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}
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if dest.Addr().Is6() && gateway.Addr().Is6() {
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return gateway, nil
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}
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}
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return netip.Prefix{}, fmt.Errorf("no gateway found for %v in the list of vpn networks", dest)
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}
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