mirror of https://github.com/slackhq/nebula.git
156 lines
3.0 KiB
Go
156 lines
3.0 KiB
Go
//go:build ios && !e2e_testing
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// +build ios,!e2e_testing
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package overlay
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import (
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"errors"
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"fmt"
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"io"
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"net/netip"
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"os"
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"sync"
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"sync/atomic"
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"syscall"
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"github.com/gaissmai/bart"
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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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type tun struct {
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io.ReadWriteCloser
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cidr netip.Prefix
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Routes atomic.Pointer[[]Route]
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routeTree atomic.Pointer[bart.Table[netip.Addr]]
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l *logrus.Logger
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}
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func newTun(_ *config.C, _ *logrus.Logger, _ netip.Prefix, _ bool) (*tun, error) {
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return nil, fmt.Errorf("newTun not supported in iOS")
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}
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func newTunFromFd(c *config.C, l *logrus.Logger, deviceFd int, cidr netip.Prefix) (*tun, error) {
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file := os.NewFile(uintptr(deviceFd), "/dev/tun")
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t := &tun{
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cidr: cidr,
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ReadWriteCloser: &tunReadCloser{f: file},
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l: l,
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}
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err := t.reload(c, true)
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if err != nil {
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return nil, err
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}
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c.RegisterReloadCallback(func(c *config.C) {
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err := t.reload(c, false)
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if err != nil {
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util.LogWithContextIfNeeded("failed to reload tun device", err, t.l)
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}
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})
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return t, nil
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}
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func (t *tun) Activate() error {
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return nil
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}
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func (t *tun) reload(c *config.C, initial bool) error {
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change, routes, err := getAllRoutesFromConfig(c, t.cidr, initial)
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if err != nil {
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return err
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}
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if !initial && !change {
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return nil
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}
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routeTree, err := makeRouteTree(t.l, routes, false)
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if err != nil {
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return err
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}
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// Teach nebula how to handle the routes
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t.Routes.Store(&routes)
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t.routeTree.Store(routeTree)
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return nil
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}
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func (t *tun) RouteFor(ip netip.Addr) netip.Addr {
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r, _ := t.routeTree.Load().Lookup(ip)
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return r
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}
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// The following is hoisted up from water, we do this so we can inject our own fd on iOS
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type tunReadCloser struct {
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f io.ReadWriteCloser
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rMu sync.Mutex
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rBuf []byte
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wMu sync.Mutex
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wBuf []byte
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}
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func (tr *tunReadCloser) Read(to []byte) (int, error) {
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tr.rMu.Lock()
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defer tr.rMu.Unlock()
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if cap(tr.rBuf) < len(to)+4 {
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tr.rBuf = make([]byte, len(to)+4)
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}
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tr.rBuf = tr.rBuf[:len(to)+4]
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n, err := tr.f.Read(tr.rBuf)
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copy(to, tr.rBuf[4:])
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return n - 4, err
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}
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func (tr *tunReadCloser) Write(from []byte) (int, error) {
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if len(from) == 0 {
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return 0, syscall.EIO
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}
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tr.wMu.Lock()
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defer tr.wMu.Unlock()
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if cap(tr.wBuf) < len(from)+4 {
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tr.wBuf = make([]byte, len(from)+4)
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}
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tr.wBuf = tr.wBuf[:len(from)+4]
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// Determine the IP Family for the NULL L2 Header
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ipVer := from[0] >> 4
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if ipVer == 4 {
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tr.wBuf[3] = syscall.AF_INET
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} else if ipVer == 6 {
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tr.wBuf[3] = syscall.AF_INET6
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} else {
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return 0, errors.New("unable to determine IP version from packet")
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}
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copy(tr.wBuf[4:], from)
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n, err := tr.f.Write(tr.wBuf)
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return n - 4, err
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}
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func (tr *tunReadCloser) Close() error {
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return tr.f.Close()
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}
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func (t *tun) Cidr() netip.Prefix {
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return t.cidr
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}
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func (t *tun) Name() string {
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return "iOS"
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}
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func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
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return nil, fmt.Errorf("TODO: multiqueue not implemented for ios")
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}
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