Revert "types/netmap,wgengine/magicsock: propagate CapVer to magicsock.endpoint (#16244)" (#16322)

This reverts commit 6a93b17c8c.

The reverted commit added more complexity than it was worth at the
current stage. Handling delta CapVer changes requires extensive changes
to relayManager datastructures in order to also support delta updates of
relay servers.

Updates tailscale/corp#27502

Signed-off-by: Jordan Whited <jordan@tailscale.com>

types/netmap/nodemut.go

@@ -69,17 +69,6 @@ func (m NodeMutationLastSeen) Apply(n *tailcfg.Node) {
 	n.LastSeen = ptr.To(m.LastSeen)
 }
 
-// NodeMutationCap is a NodeMutation that says a node's
-// [tailcfg.CapabilityVersion] value has changed.
-type NodeMutationCap struct {
-	mutatingNodeID
-	Cap tailcfg.CapabilityVersion
-}
-
-func (m NodeMutationCap) Apply(n *tailcfg.Node) {
-	n.Cap = m.Cap
-}
-
 var peerChangeFields = sync.OnceValue(func() []reflect.StructField {
 	var fields []reflect.StructField
 	rt := reflect.TypeFor[tailcfg.PeerChange]()
@@ -116,8 +105,6 @@ func NodeMutationsFromPatch(p *tailcfg.PeerChange) (_ []NodeMutation, ok bool) {
 			ret = append(ret, NodeMutationOnline{mutatingNodeID(p.NodeID), *p.Online})
 		case "LastSeen":
 			ret = append(ret, NodeMutationLastSeen{mutatingNodeID(p.NodeID), *p.LastSeen})
-		case "Cap":
-			ret = append(ret, NodeMutationCap{mutatingNodeID(p.NodeID), p.Cap})
 		}
 	}
 	return ret, true

types/netmap/nodemut_test.go

@@ -177,14 +177,6 @@ func TestMutationsFromMapResponse(t *testing.T) {
 			},
 			want: nil,
 		},
-		{
-			name: "patch-cap",
-			mr: fromChanges(&tailcfg.PeerChange{
-				NodeID: 1,
-				Cap:    2,
-			}),
-			want: muts(NodeMutationCap{1, 2}),
-		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -203,7 +195,6 @@ func TestMutationsFromMapResponse(t *testing.T) {
 					NodeMutationDERPHome{},
 					NodeMutationOnline{},
 					NodeMutationLastSeen{},
-					NodeMutationCap{},
 				)); diff != "" {
 				t.Errorf("wrong result (-want +got):\n%s", diff)
 			}

wgengine/magicsock/magicsock.go

@@ -3263,10 +3263,6 @@ func (c *Conn) onNodeMutationsUpdate(update NodeMutationsUpdate) {
 			ep.mu.Lock()
 			ep.setEndpointsLocked(views.SliceOf(m.Endpoints))
 			ep.mu.Unlock()
-		case netmap.NodeMutationCap:
-			ep.mu.Lock()
-			ep.relayCapable = capVerIsRelayCapable(m.Cap)
-			ep.mu.Unlock()
 		}
 	}
 }