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net/tsdial: give netstack a Dialer, start refactoring name resolution

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This starts to refactor tsdial.Dialer's name resolution to have
different stages: in-memory MagicDNS vs system resolution. A future
change will plug in ExitDNS resolution.

This also plumbs a Dialer into netstack and unexports the dnsMap
internals.

And it removes some of the async AddNetworkMapCallback usage and
replaces it with synchronous updates of the Dialer's netmap
from LocalBackend, since the LocalBackend has the Dialer too.

Updates #3475

Change-Id: Idcb7b1169878c74f0522f5151031ccbc49fe4cb4
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This commit is contained in:
Brad Fitzpatrick
2021-12-02 11:10:35 -08:00
committed by Brad Fitzpatrick
parent 768baafcb5
commit adc5997592
10 changed files with 99 additions and 83 deletions
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29
wgengine/netstack/netstack.go
View File

@@ -71,6 +71,7 @@ type Impl struct {
e wgengine.Engine
mc *magicsock.Conn
logf logger.Logf
dialer *tsdial.Dialer
// atomicIsLocalIPFunc holds a func that reports whether an IP
// is a local (non-subnet) Tailscale IP address of this
@@ -78,8 +79,7 @@ type Impl struct {
// updates.
atomicIsLocalIPFunc atomic.Value // of func(netaddr.IP) bool
mu sync.Mutex
dns tsdial.DNSMap
mu sync.Mutex
// connsOpenBySubnetIP keeps track of number of connections open
// for each subnet IP temporarily registered on netstack for active
// TCP connections, so they can be unregistered when connections are
@@ -91,7 +91,7 @@ const nicID = 1
const mtu = 1500
// Create creates and populates a new Impl.
func Create(logf logger.Logf, tundev *tstun.Wrapper, e wgengine.Engine, mc *magicsock.Conn) (*Impl, error) {
func Create(logf logger.Logf, tundev *tstun.Wrapper, e wgengine.Engine, mc *magicsock.Conn, dialer *tsdial.Dialer) (*Impl, error) {
if mc == nil {
return nil, errors.New("nil magicsock.Conn")
}
@@ -104,6 +104,9 @@ func Create(logf logger.Logf, tundev *tstun.Wrapper, e wgengine.Engine, mc *magi
if e == nil {
return nil, errors.New("nil Engine")
}
if dialer == nil {
return nil, errors.New("nil Dialer")
}
ipstack := stack.New(stack.Options{
NetworkProtocols: []stack.NetworkProtocolFactory{ipv4.NewProtocol, ipv6.NewProtocol},
TransportProtocols: []stack.TransportProtocolFactory{tcp.NewProtocol, udp.NewProtocol, icmp.NewProtocol4, icmp.NewProtocol6},
@@ -139,6 +142,7 @@ func Create(logf logger.Logf, tundev *tstun.Wrapper, e wgengine.Engine, mc *magi
tundev: tundev,
e: e,
mc: mc,
dialer: dialer,
connsOpenBySubnetIP: make(map[netaddr.IP]int),
}
ns.atomicIsLocalIPFunc.Store(tsaddr.NewContainsIPFunc(nil))
@@ -179,12 +183,6 @@ func (ns *Impl) Start() error {
return nil
}
func (ns *Impl) updateDNS(nm *netmap.NetworkMap) {
ns.mu.Lock()
defer ns.mu.Unlock()
ns.dns = tsdial.DNSMapFromNetworkMap(nm)
}
func (ns *Impl) addSubnetAddress(ip netaddr.IP) {
ns.mu.Lock()
ns.connsOpenBySubnetIP[ip]++
@@ -230,7 +228,6 @@ func ipPrefixToAddressWithPrefix(ipp netaddr.IPPrefix) tcpip.AddressWithPrefix {
func (ns *Impl) updateIPs(nm *netmap.NetworkMap) {
ns.atomicIsLocalIPFunc.Store(tsaddr.NewContainsIPFunc(nm.Addresses))
ns.updateDNS(nm)
oldIPs := make(map[tcpip.AddressWithPrefix]bool)
for _, protocolAddr := range ns.ipstack.AllAddresses()[nicID] {
@@ -299,11 +296,7 @@ func (ns *Impl) updateIPs(nm *netmap.NetworkMap) {
}
func (ns *Impl) DialContextTCP(ctx context.Context, addr string) (*gonet.TCPConn, error) {
ns.mu.Lock()
dnsMap := ns.dns
ns.mu.Unlock()
remoteIPPort, err := dnsMap.Resolve(ctx, addr)
remoteIPPort, err := ns.dialer.Resolve(ctx, "tcp", addr)
if err != nil {
return nil, err
}
@@ -323,11 +316,7 @@ func (ns *Impl) DialContextTCP(ctx context.Context, addr string) (*gonet.TCPConn
}
func (ns *Impl) DialContextUDP(ctx context.Context, addr string) (*gonet.UDPConn, error) {
ns.mu.Lock()
dnsMap := ns.dns
ns.mu.Unlock()
remoteIPPort, err := dnsMap.Resolve(ctx, addr)
remoteIPPort, err := ns.dialer.Resolve(ctx, "udp", addr)
if err != nil {
return nil, err
}