From fe50cd0c48442637918b07a44e77d84951125306 Mon Sep 17 00:00:00 2001
From: Brad Fitzpatrick <bradfitz@tailscale.com>
Date: Thu, 25 Jun 2020 11:04:52 -0700
Subject: [PATCH] ipn, wgengine: plumb NetworkMap down to magicsock

Now we can have magicsock make decisions based on tailcfg.Debug
settings sent by the server.

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
---
 ipn/local.go                    |  1 +
 wgengine/magicsock/magicsock.go | 21 +++++++++++++++++++++
 wgengine/userspace.go           |  5 +++++
 wgengine/watchdog.go            |  4 ++++
 wgengine/wgengine.go            |  8 ++++++++
 5 files changed, 39 insertions(+)

diff --git a/ipn/local.go b/ipn/local.go
index b682f261a..a940ca4ce 100644
--- a/ipn/local.go
+++ b/ipn/local.go
@@ -230,6 +230,7 @@ func (b *LocalBackend) setClientStatus(st controlclient.Status) {
 		if changed {
 			b.updateFilter(st.NetMap)
 			b.updateDNSMap(st.NetMap)
+			b.e.SetNetworkMap(st.NetMap)
 		}
 		if disableDERP {
 			b.e.SetDERPMap(nil)
diff --git a/wgengine/magicsock/magicsock.go b/wgengine/magicsock/magicsock.go
index 5aba3bbbd..792dc00ab 100644
--- a/wgengine/magicsock/magicsock.go
+++ b/wgengine/magicsock/magicsock.go
@@ -30,6 +30,7 @@ import (
 	"github.com/tailscale/wireguard-go/wgcfg"
 	"golang.org/x/time/rate"
 	"inet.af/netaddr"
+	"tailscale.com/control/controlclient"
 	"tailscale.com/derp"
 	"tailscale.com/derp/derphttp"
 	"tailscale.com/ipn/ipnstate"
@@ -107,6 +108,7 @@ type Conn struct {
 	netInfoLast *tailcfg.NetInfo
 
 	derpMap     *tailcfg.DERPMap // nil (or zero regions/nodes) means DERP is disabled
+	netMap      *controlclient.NetworkMap
 	privateKey  key.Private
 	myDerp      int                // nearest DERP region ID; 0 means none/unknown
 	derpStarted chan struct{}      // closed on first connection to DERP; for tests
@@ -1347,6 +1349,25 @@ func (c *Conn) SetDERPMap(dm *tailcfg.DERPMap) {
 	go c.ReSTUN("derp-map-update")
 }
 
+// SetNetworkMap is called when the control client gets a new network
+// map from the control server.
+//
+// It should not use the DERPMap field of NetworkMap; that's
+// conditionally sent to SetDERPMap instead.
+func (c *Conn) SetNetworkMap(nm *controlclient.NetworkMap) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	if reflect.DeepEqual(nm, c.netMap) {
+		return
+	}
+	c.logf("magicsock: got updated network map")
+
+	c.netMap = nm
+	// TODO: look at Debug fields
+	// TODO: look at DiscoKey fields to reset AddrSet states when node restarts
+}
+
 func (c *Conn) wantDerpLocked() bool { return c.derpMap != nil }
 
 // c.mu must be held.
diff --git a/wgengine/userspace.go b/wgengine/userspace.go
index c3b8b93f5..985605a0d 100644
--- a/wgengine/userspace.go
+++ b/wgengine/userspace.go
@@ -25,6 +25,7 @@ import (
 	"github.com/tailscale/wireguard-go/tun"
 	"github.com/tailscale/wireguard-go/wgcfg"
 	"go4.org/mem"
+	"tailscale.com/control/controlclient"
 	"tailscale.com/ipn/ipnstate"
 	"tailscale.com/net/interfaces"
 	"tailscale.com/tailcfg"
@@ -830,6 +831,10 @@ func (e *userspaceEngine) SetDERPMap(dm *tailcfg.DERPMap) {
 	e.magicConn.SetDERPMap(dm)
 }
 
+func (e *userspaceEngine) SetNetworkMap(nm *controlclient.NetworkMap) {
+	e.magicConn.SetNetworkMap(nm)
+}
+
 func (e *userspaceEngine) SetDiscoPrivateKey(k key.Private) {
 	e.magicConn.SetDiscoPrivateKey(k)
 }
diff --git a/wgengine/watchdog.go b/wgengine/watchdog.go
index 06e07a134..4e39d83bf 100644
--- a/wgengine/watchdog.go
+++ b/wgengine/watchdog.go
@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/tailscale/wireguard-go/wgcfg"
+	"tailscale.com/control/controlclient"
 	"tailscale.com/ipn/ipnstate"
 	"tailscale.com/tailcfg"
 	"tailscale.com/types/key"
@@ -97,6 +98,9 @@ func (e *watchdogEngine) LinkChange(isExpensive bool) {
 func (e *watchdogEngine) SetDERPMap(m *tailcfg.DERPMap) {
 	e.watchdog("SetDERPMap", func() { e.wrap.SetDERPMap(m) })
 }
+func (e *watchdogEngine) SetNetworkMap(nm *controlclient.NetworkMap) {
+	e.watchdog("SetNetworkMap", func() { e.wrap.SetNetworkMap(nm) })
+}
 func (e *watchdogEngine) SetDiscoPrivateKey(k key.Private) {
 	e.watchdog("SetDiscoPrivateKey", func() { e.wrap.SetDiscoPrivateKey(k) })
 }
diff --git a/wgengine/wgengine.go b/wgengine/wgengine.go
index b245a77f1..8a1aaa833 100644
--- a/wgengine/wgengine.go
+++ b/wgengine/wgengine.go
@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/tailscale/wireguard-go/wgcfg"
+	"tailscale.com/control/controlclient"
 	"tailscale.com/ipn/ipnstate"
 	"tailscale.com/tailcfg"
 	"tailscale.com/types/key"
@@ -105,6 +106,13 @@ type Engine interface {
 	// is configured.
 	SetDERPMap(*tailcfg.DERPMap)
 
+	// SetNetworkMap informs the engine of the latest network map
+	// from the server. The network map's DERPMap field should be
+	// ignored as as it might be disabled; get it from SetDERPMap
+	// instead.
+	// The network map should only be read from.
+	SetNetworkMap(*controlclient.NetworkMap)
+
 	// SetNetInfoCallback sets the function to call when a
 	// new NetInfo summary is available.
 	SetNetInfoCallback(NetInfoCallback)