Revert "ipnlocal, magicsock: store last suggested exit node id in local backend (#11959)"

This reverts commit 35872e86d29a4a46d20d2b7cbd4927ee83fedac4.

Signed-off-by: Claire Wang <claire@tailscale.com>

ipn/ipnlocal/local.go

@@ -151,12 +151,6 @@ type watchSession struct {
 	sessionID string
 }
 
-// lastSuggestedExitNode stores the last suggested exit node ID and name in local backend.
-type lastSuggestedExitNode struct {
-	id   tailcfg.StableNodeID
-	name string
-}
-
 // LocalBackend is the glue between the major pieces of the Tailscale
 // network software: the cloud control plane (via controlclient), the
 // network data plane (via wgengine), and the user-facing UIs and CLIs
@@ -330,10 +324,6 @@ type LocalBackend struct {
 
 	// outgoingFiles keeps track of Taildrop outgoing files keyed to their OutgoingFile.ID
 	outgoingFiles map[string]*ipn.OutgoingFile
-
-	// lastSuggestedExitNode stores the last suggested exit node ID and name.
-	// lastSuggestedExitNode updates whenever the suggestion changes.
-	lastSuggestedExitNode lastSuggestedExitNode
 }
 
 // HealthTracker returns the health tracker for the backend.
@@ -5967,8 +5957,7 @@ func (b *LocalBackend) resetForProfileChangeLockedOnEntry(unlock unlockOnce) err
 	}
 	b.lastServeConfJSON = mem.B(nil)
 	b.serveConfig = ipn.ServeConfigView{}
-	b.lastSuggestedExitNode = lastSuggestedExitNode{} // Reset last suggested exit node.
+	b.enterStateLockedOnEntry(ipn.NoState, unlock) // Reset state; releases b.mu
-	b.enterStateLockedOnEntry(ipn.NoState, unlock)    // Reset state; releases b.mu
 	b.health.SetLocalLogConfigHealth(nil)
 	return b.Start(ipn.Options{})
 }
@@ -6345,7 +6334,6 @@ func mayDeref[T any](p *T) (v T) {
 
 var ErrNoPreferredDERP = errors.New("no preferred DERP, try again later")
 var ErrCannotSuggestExitNode = errors.New("unable to suggest an exit node, try again later")
-var ErrUnableToSuggestLastExitNode = errors.New("unable to suggest last exit node")
 
 // SuggestExitNode computes a suggestion based on the current netmap and last netcheck report. If
 // there are multiple equally good options, one is selected at random, so the result is not stable. To be
@@ -6358,41 +6346,13 @@ func (b *LocalBackend) SuggestExitNode() (response apitype.ExitNodeSuggestionRes
 	b.mu.Lock()
 	lastReport := b.MagicConn().GetLastNetcheckReport(b.ctx)
 	netMap := b.netMap
-	lastSuggestedExitNode := b.lastSuggestedExitNode
 	b.mu.Unlock()
 	if lastReport == nil || netMap == nil {
-		last, err := suggestLastExitNode(lastSuggestedExitNode)
+		return response, ErrCannotSuggestExitNode
-		if err != nil {
-			return response, ErrCannotSuggestExitNode
-		}
-		return last, err
 	}
 	seed := time.Now().UnixNano()
 	r := rand.New(rand.NewSource(seed))
-	res, err := suggestExitNode(lastReport, netMap, r)
+	return suggestExitNode(lastReport, netMap, r)
-	if err != nil {
-		last, err := suggestLastExitNode(lastSuggestedExitNode)
-		if err != nil {
-			return response, ErrCannotSuggestExitNode
-		}
-		return last, err
-	}
-	b.mu.Lock()
-	b.lastSuggestedExitNode.id = res.ID
-	b.lastSuggestedExitNode.name = res.Name
-	b.mu.Unlock()
-	return res, err
-}
-
-// suggestLastExitNode formats a response with the last suggested exit node's ID and name.
-// Used as a fallback before returning a nil response and error.
-func suggestLastExitNode(lastSuggestedExitNode lastSuggestedExitNode) (res apitype.ExitNodeSuggestionResponse, err error) {
-	if lastSuggestedExitNode.id != "" && lastSuggestedExitNode.name != "" {
-		res.ID = lastSuggestedExitNode.id
-		res.Name = lastSuggestedExitNode.name
-		return res, nil
-	}
-	return res, ErrUnableToSuggestLastExitNode
 }
 
 func suggestExitNode(report *netcheck.Report, netMap *netmap.NetworkMap, r *rand.Rand) (res apitype.ExitNodeSuggestionResponse, err error) {

ipn/ipnlocal/local_test.go

@@ -25,7 +25,6 @@ import (
 	"golang.org/x/net/dns/dnsmessage"
 	"tailscale.com/appc"
 	"tailscale.com/appc/appctest"
-	"tailscale.com/client/tailscale/apitype"
 	"tailscale.com/clientupdate"
 	"tailscale.com/control/controlclient"
 	"tailscale.com/drive"
@@ -3438,357 +3437,6 @@ func TestMinLatencyDERPregion(t *testing.T) {
 	}
 }
 
-func TestSuggestLastExitNode(t *testing.T) {
-	tests := []struct {
-		name                      string
-		lastSuggestedExitNode     lastSuggestedExitNode
-		wantRes                   apitype.ExitNodeSuggestionResponse
-		wantLastSuggestedExitNode lastSuggestedExitNode
-		wantErr                   error
-	}{
-		{
-			name:                      "last suggested exit node is populated",
-			lastSuggestedExitNode:     lastSuggestedExitNode{id: "test", name: "test"},
-			wantRes:                   apitype.ExitNodeSuggestionResponse{ID: "test", Name: "test"},
-			wantLastSuggestedExitNode: lastSuggestedExitNode{id: "test", name: "test"},
-		},
-		{
-			name:    "last suggested exit node is not populated",
-			wantErr: ErrUnableToSuggestLastExitNode,
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			got, err := suggestLastExitNode(tt.lastSuggestedExitNode)
-			if got != tt.wantRes || err != tt.wantErr {
-				t.Errorf("got %v error %v, want %v error %v", got, err, tt.wantRes, tt.wantErr)
-			}
-		})
-	}
-}
-
-func TestLocalBackendSuggestExitNode(t *testing.T) {
-	tests := []struct {
-		name                      string
-		lastSuggestedExitNode     lastSuggestedExitNode
-		report                    netcheck.Report
-		netMap                    netmap.NetworkMap
-		wantID                    tailcfg.StableNodeID
-		wantName                  string
-		wantErr                   error
-		wantLastSuggestedExitNode lastSuggestedExitNode
-	}{
-		{
-			name:                  "nil netmap, returns last suggested exit node",
-			lastSuggestedExitNode: lastSuggestedExitNode{name: "test", id: "test"},
-			report: netcheck.Report{
-				RegionLatency: map[int]time.Duration{
-					1: 0,
-					2: -1,
-					3: 0,
-				},
-			},
-			wantID:                    "test",
-			wantName:                  "test",
-			wantLastSuggestedExitNode: lastSuggestedExitNode{name: "test", id: "test"},
-		},
-		{
-			name:                  "nil report, returns last suggested exit node",
-			lastSuggestedExitNode: lastSuggestedExitNode{name: "test", id: "test"},
-			netMap: netmap.NetworkMap{
-				SelfNode: (&tailcfg.Node{
-					Addresses: []netip.Prefix{
-						netip.MustParsePrefix("100.64.1.1/32"),
-						netip.MustParsePrefix("fe70::1/128"),
-					},
-				}).View(),
-				DERPMap: &tailcfg.DERPMap{
-					Regions: map[int]*tailcfg.DERPRegion{
-						1: {},
-						2: {},
-						3: {},
-					},
-				},
-			},
-			wantID:                    "test",
-			wantName:                  "test",
-			wantLastSuggestedExitNode: lastSuggestedExitNode{name: "test", id: "test"},
-		},
-		{
-			name:                  "found better derp node, last suggested exit node updates",
-			lastSuggestedExitNode: lastSuggestedExitNode{name: "test", id: "test"},
-			report: netcheck.Report{
-				RegionLatency: map[int]time.Duration{
-					1: 10,
-					2: 10,
-					3: 5,
-				},
-				PreferredDERP: 1,
-			},
-			netMap: netmap.NetworkMap{
-				SelfNode: (&tailcfg.Node{
-					Addresses: []netip.Prefix{
-						netip.MustParsePrefix("100.64.1.1/32"),
-						netip.MustParsePrefix("fe70::1/128"),
-					},
-				}).View(),
-				DERPMap: &tailcfg.DERPMap{
-					Regions: map[int]*tailcfg.DERPRegion{
-						1: {},
-						2: {},
-						3: {},
-					},
-				},
-				Peers: []tailcfg.NodeView{
-					(&tailcfg.Node{
-						ID:       2,
-						StableID: "test",
-						Name:     "test",
-						DERP:     "127.3.3.40:1",
-						AllowedIPs: []netip.Prefix{
-							netip.MustParsePrefix("0.0.0.0/0"), netip.MustParsePrefix("::/0"),
-						},
-						CapMap: (tailcfg.NodeCapMap)(map[tailcfg.NodeCapability][]tailcfg.RawMessage{
-							tailcfg.NodeAttrSuggestExitNode: {},
-						}),
-					}).View(),
-					(&tailcfg.Node{
-						ID:       3,
-						StableID: "foo",
-						Name:     "foo",
-						DERP:     "127.3.3.40:3",
-						AllowedIPs: []netip.Prefix{
-							netip.MustParsePrefix("0.0.0.0/0"), netip.MustParsePrefix("::/0"),
-						},
-						CapMap: (tailcfg.NodeCapMap)(map[tailcfg.NodeCapability][]tailcfg.RawMessage{
-							tailcfg.NodeAttrSuggestExitNode: {},
-						}),
-					}).View(),
-				},
-			},
-			wantID:                    "foo",
-			wantName:                  "foo",
-			wantLastSuggestedExitNode: lastSuggestedExitNode{name: "foo", id: "foo"},
-		},
-		{
-			name:                  "found better mullvad node, last suggested exit node updates",
-			lastSuggestedExitNode: lastSuggestedExitNode{name: "San Jose", id: "3"},
-			report: netcheck.Report{
-				RegionLatency: map[int]time.Duration{
-					1: 0,
-					2: 0,
-					3: 0,
-				},
-				PreferredDERP: 1,
-			},
-			netMap: netmap.NetworkMap{
-				SelfNode: (&tailcfg.Node{
-					Addresses: []netip.Prefix{
-						netip.MustParsePrefix("100.64.1.1/32"),
-						netip.MustParsePrefix("fe70::1/128"),
-					},
-				}).View(),
-				DERPMap: &tailcfg.DERPMap{
-					Regions: map[int]*tailcfg.DERPRegion{
-						1: {
-							Latitude:  40.73061,
-							Longitude: -73.935242,
-						},
-						2: {},
-						3: {},
-					},
-				},
-				Peers: []tailcfg.NodeView{
-					(&tailcfg.Node{
-						ID:       2,
-						StableID: "2",
-						AllowedIPs: []netip.Prefix{
-							netip.MustParsePrefix("0.0.0.0/0"), netip.MustParsePrefix("::/0"),
-						},
-						Name: "Dallas",
-						Hostinfo: (&tailcfg.Hostinfo{
-							Location: &tailcfg.Location{
-								Latitude:  32.89748,
-								Longitude: -97.040443,
-								Priority:  100,
-							},
-						}).View(),
-						CapMap: (tailcfg.NodeCapMap)(map[tailcfg.NodeCapability][]tailcfg.RawMessage{
-							tailcfg.NodeAttrSuggestExitNode: {},
-						}),
-					}).View(),
-					(&tailcfg.Node{
-						ID:       3,
-						StableID: "3",
-						AllowedIPs: []netip.Prefix{
-							netip.MustParsePrefix("0.0.0.0/0"), netip.MustParsePrefix("::/0"),
-						},
-						Name: "San Jose",
-						Hostinfo: (&tailcfg.Hostinfo{
-							Location: &tailcfg.Location{
-								Latitude:  37.3382082,
-								Longitude: -121.8863286,
-								Priority:  20,
-							},
-						}).View(),
-						CapMap: (tailcfg.NodeCapMap)(map[tailcfg.NodeCapability][]tailcfg.RawMessage{
-							tailcfg.NodeAttrSuggestExitNode: {},
-						}),
-					}).View(),
-				},
-			},
-			wantID:                    "2",
-			wantName:                  "Dallas",
-			wantLastSuggestedExitNode: lastSuggestedExitNode{name: "Dallas", id: "2"},
-		},
-		{
-			name:                  "ErrNoPreferredDERP, use last suggested exit node",
-			lastSuggestedExitNode: lastSuggestedExitNode{name: "test", id: "test"},
-			report: netcheck.Report{
-				RegionLatency: map[int]time.Duration{
-					1: 10,
-					2: 10,
-					3: 5,
-				},
-				PreferredDERP: 0,
-			},
-			netMap: netmap.NetworkMap{
-				SelfNode: (&tailcfg.Node{
-					Addresses: []netip.Prefix{
-						netip.MustParsePrefix("100.64.1.1/32"),
-						netip.MustParsePrefix("fe70::1/128"),
-					},
-				}).View(),
-				DERPMap: &tailcfg.DERPMap{
-					Regions: map[int]*tailcfg.DERPRegion{
-						1: {},
-						2: {},
-						3: {},
-					},
-				},
-				Peers: []tailcfg.NodeView{
-					(&tailcfg.Node{
-						ID:       2,
-						StableID: "test",
-						Name:     "test",
-						DERP:     "127.3.3.40:1",
-						AllowedIPs: []netip.Prefix{
-							netip.MustParsePrefix("0.0.0.0/0"), netip.MustParsePrefix("::/0"),
-						},
-						CapMap: (tailcfg.NodeCapMap)(map[tailcfg.NodeCapability][]tailcfg.RawMessage{
-							tailcfg.NodeAttrSuggestExitNode: {},
-						}),
-					}).View(),
-					(&tailcfg.Node{
-						ID:       3,
-						StableID: "foo",
-						Name:     "foo",
-						DERP:     "127.3.3.40:3",
-						AllowedIPs: []netip.Prefix{
-							netip.MustParsePrefix("0.0.0.0/0"), netip.MustParsePrefix("::/0"),
-						},
-						CapMap: (tailcfg.NodeCapMap)(map[tailcfg.NodeCapability][]tailcfg.RawMessage{
-							tailcfg.NodeAttrSuggestExitNode: {},
-						}),
-					}).View(),
-				},
-			},
-			wantID:                    "test",
-			wantName:                  "test",
-			wantLastSuggestedExitNode: lastSuggestedExitNode{name: "test", id: "test"},
-		},
-		{
-			name:                  "ErrNoPreferredDERP, use last suggested exit node",
-			lastSuggestedExitNode: lastSuggestedExitNode{name: "test", id: "test"},
-			report: netcheck.Report{
-				RegionLatency: map[int]time.Duration{
-					1: 10,
-					2: 10,
-					3: 5,
-				},
-				PreferredDERP: 0,
-			},
-			netMap: netmap.NetworkMap{
-				SelfNode: (&tailcfg.Node{
-					Addresses: []netip.Prefix{
-						netip.MustParsePrefix("100.64.1.1/32"),
-						netip.MustParsePrefix("fe70::1/128"),
-					},
-				}).View(),
-				DERPMap: &tailcfg.DERPMap{
-					Regions: map[int]*tailcfg.DERPRegion{
-						1: {},
-						2: {},
-						3: {},
-					},
-				},
-				Peers: []tailcfg.NodeView{
-					(&tailcfg.Node{
-						ID:       2,
-						StableID: "test",
-						Name:     "test",
-						DERP:     "127.3.3.40:1",
-						AllowedIPs: []netip.Prefix{
-							netip.MustParsePrefix("0.0.0.0/0"), netip.MustParsePrefix("::/0"),
-						},
-						CapMap: (tailcfg.NodeCapMap)(map[tailcfg.NodeCapability][]tailcfg.RawMessage{
-							tailcfg.NodeAttrSuggestExitNode: {},
-						}),
-					}).View(),
-					(&tailcfg.Node{
-						ID:       3,
-						StableID: "foo",
-						Name:     "foo",
-						DERP:     "127.3.3.40:3",
-						AllowedIPs: []netip.Prefix{
-							netip.MustParsePrefix("0.0.0.0/0"), netip.MustParsePrefix("::/0"),
-						},
-						CapMap: (tailcfg.NodeCapMap)(map[tailcfg.NodeCapability][]tailcfg.RawMessage{
-							tailcfg.NodeAttrSuggestExitNode: {},
-						}),
-					}).View(),
-				},
-			},
-			wantID:                    "test",
-			wantName:                  "test",
-			wantLastSuggestedExitNode: lastSuggestedExitNode{name: "test", id: "test"},
-		},
-		{
-			name: "unable to use last suggested exit node",
-			report: netcheck.Report{
-				RegionLatency: map[int]time.Duration{
-					1: 10,
-					2: 10,
-					3: 5,
-				},
-				PreferredDERP: 0,
-			},
-			wantErr: ErrCannotSuggestExitNode,
-		},
-	}
-
-	for _, tt := range tests {
-		lb := newTestLocalBackend(t)
-		lb.lastSuggestedExitNode = tt.lastSuggestedExitNode
-		lb.netMap = &tt.netMap
-		lb.sys.MagicSock.Get().SetLastNetcheckReport(context.Background(), tt.report)
-		got, err := lb.SuggestExitNode()
-		if got.ID != tt.wantID {
-			t.Errorf("ID=%v, want=%v", got.ID, tt.wantID)
-		}
-		if got.Name != tt.wantName {
-			t.Errorf("Name=%v, want=%v", got.Name, tt.wantName)
-		}
-		if lb.lastSuggestedExitNode != tt.wantLastSuggestedExitNode {
-			t.Errorf("lastSuggestedExitNode=%v, want=%v", lb.lastSuggestedExitNode, tt.wantLastSuggestedExitNode)
-		}
-		if err != tt.wantErr {
-			t.Errorf("Error=%v, want=%v", err, tt.wantErr)
-		}
-	}
-}
-
 func TestEnableAutoUpdates(t *testing.T) {
 	lb := newTestLocalBackend(t)
 

wgengine/magicsock/magicsock.go

@@ -3088,9 +3088,3 @@ func (c *Conn) GetLastNetcheckReport(ctx context.Context) *netcheck.Report {
 	}
 	return lastReport
 }
-
-// SetLastNetcheckReport sets local backend's last netcheck report.
-// Used for testing purposes.
-func (c *Conn) SetLastNetcheckReport(ctx context.Context, report netcheck.Report) {
-	c.lastNetCheckReport.Store(&report)
-}