Revert "tailcfg, controlclient, magicsock: request IPv6 endpoints, but ignore them"

Breaks something deep in wireguard or magicsock's brainstem, no packets at all
can flow. All received packets fail decryption with "invalid mac1".

This reverts commit 94024355ed.

Signed-off-by: David Anderson <dave@natulte.net>

control/controlclient/direct.go

@@ -448,13 +448,12 @@ func (c *Direct) PollNetMap(ctx context.Context, maxPolls int, cb func(*NetworkM
 	c.logf("PollNetMap: stream=%v :%v %v\n", maxPolls, localPort, ep)
 
 	request := tailcfg.MapRequest{
-		Version:     4,
-		IncludeIPv6: true,
-		KeepAlive:   c.keepAlive,
-		NodeKey:     tailcfg.NodeKey(persist.PrivateNodeKey.Public()),
-		Endpoints:   ep,
-		Stream:      allowStream,
-		Hostinfo:    hostinfo,
+		Version:   4,
+		KeepAlive: c.keepAlive,
+		NodeKey:   tailcfg.NodeKey(persist.PrivateNodeKey.Public()),
+		Endpoints: ep,
+		Stream:    allowStream,
+		Hostinfo:  hostinfo,
 	}
 	if c.newDecompressor != nil {
 		request.Compress = "zstd"

tailcfg/tailcfg.go

@@ -391,14 +391,13 @@ type RegisterResponse struct {
 // using the local machine key, and sent to:
 //	https://login.tailscale.com/machine/<mkey hex>/map
 type MapRequest struct {
-	Version     int    // current version is 4
-	Compress    string // "zstd" or "" (no compression)
-	KeepAlive   bool   // server sends keep-alives
-	NodeKey     NodeKey
-	Endpoints   []string // caller's endpoints (IPv4 or IPv6)
-	IncludeIPv6 bool     // include IPv6 endpoints in returned Node Endpoints
-	Stream      bool     // if true, multiple MapResponse objects are returned
-	Hostinfo    *Hostinfo
+	Version   int    // current version is 4
+	Compress  string // "zstd" or "" (no compression)
+	KeepAlive bool   // server sends keep-alives
+	NodeKey   NodeKey
+	Endpoints []string
+	Stream    bool // if true, multiple MapResponse objects are returned
+	Hostinfo  *Hostinfo
 }
 
 type MapResponse struct {

wgengine/magicsock/magicsock.go

@@ -1456,10 +1456,6 @@ func (c *Conn) CreateEndpoint(key [32]byte, addrs string) (conn.Endpoint, error)
 			}
 			if ip4 := addr.IP.To4(); ip4 != nil {
 				addr.IP = ip4
-			} else {
-				// TODO(bradfitz): stop skipping IPv6 ones for now.
-				c.logf("magicsock: CreateEndpoint: ignoring IPv6 addr %v for now", addr)
-				continue
 			}
 			a.addrs = append(a.addrs, *addr)
 		}