net/tsdial, ipn/ipnlocal: stop using netmap.NetworkMap in Dialer

tsdial.Dialer.SetNetMap rebuilt an O(n peers) map of MagicDNS names on every netmap change. As we move toward per-peer incremental deltas, this becomes quadratic. This removes it and replaces it with SetResolveMagicDNS, a callback into LocalBackend that looks up hostnames from nodeBackend's new nodeByName index (populated alongside nodeByAddr/nodeByKey on both full and delta paths). The index stores both FQDNs and short names as keys. This is the same treatment applied to netlog (8f210454d), wglog (988b0905b), and drive (1d6989408): stop pushing *netmap.NetworkMap into subsystems and instead have them pull from LocalBackend's live data via callbacks. Updates #12542 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com> Change-Id: I24557ab0c8a27636e08e4779bcfd3ec633db0a78
2026-06-24 13:14:45 -07:00
parent 8dde9b725b
commit aefb1531d1
15 changed files with 522 additions and 359 deletions
@@ -0,0 +1,89 @@
+// Copyright (c) Tailscale Inc & contributors
+// SPDX-License-Identifier: BSD-3-Clause
+
+package ipnlocal
+
+import (
+	"net/netip"
+	"testing"
+
+	"tailscale.com/tailcfg"
+	"tailscale.com/types/netmap"
+)
+
+func TestResolveMagicDNS(t *testing.T) {
+	b := newTestLocalBackend(t)
+
+	nm := &netmap.NetworkMap{
+		SelfNode: (&tailcfg.Node{
+			ID:       1,
+			Name:     "self.tail-scale.ts.net.",
+			Key:      makeNodeKeyFromID(1),
+			DiscoKey: makeDiscoKeyFromID(1),
+			Addresses: []netip.Prefix{
+				netip.MustParsePrefix("100.64.0.1/32"),
+				netip.MustParsePrefix("fd7a:115c:a1e0::1/128"),
+			},
+		}).View(),
+		Peers: []tailcfg.NodeView{
+			(&tailcfg.Node{
+				ID:       2,
+				Name:     "peer1.tail-scale.ts.net.",
+				Key:      makeNodeKeyFromID(2),
+				DiscoKey: makeDiscoKeyFromID(2),
+				Addresses: []netip.Prefix{
+					netip.MustParsePrefix("100.64.0.2/32"),
+					netip.MustParsePrefix("fd7a:115c:a1e0::2/128"),
+				},
+			}).View(),
+			(&tailcfg.Node{
+				ID:       3,
+				Name:     "v6only.tail-scale.ts.net.",
+				Key:      makeNodeKeyFromID(3),
+				DiscoKey: makeDiscoKeyFromID(3),
+				Addresses: []netip.Prefix{
+					netip.MustParsePrefix("fd7a:115c:a1e0::3/128"),
+				},
+			}).View(),
+		},
+		DNS: tailcfg.DNSConfig{
+			ExtraRecords: []tailcfg.DNSRecord{
+				{Name: "svc-foo.tail-scale.ts.net.", Value: "100.11.22.33"},
+			},
+		},
+	}
+	nm.Domain = "tail-scale.ts.net"
+	b.currentNode().SetNetMap(nm)
+
+	tests := []struct {
+		name    string
+		host    string
+		network string
+		wantIP  string
+		wantOK  bool
+	}{
+		{name: "fqdn", host: "peer1.tail-scale.ts.net", network: "tcp", wantIP: "100.64.0.2", wantOK: true},
+		{name: "short_name", host: "peer1", network: "tcp", wantIP: "100.64.0.2", wantOK: true},
+		{name: "self_fqdn", host: "self.tail-scale.ts.net", network: "tcp", wantIP: "100.64.0.1", wantOK: true},
+		{name: "self_short", host: "self", network: "tcp", wantIP: "100.64.0.1", wantOK: true},
+		{name: "tcp4", host: "peer1", network: "tcp4", wantIP: "100.64.0.2", wantOK: true},
+		{name: "tcp6", host: "peer1", network: "tcp6", wantIP: "fd7a:115c:a1e0::2", wantOK: true},
+		{name: "v6only_tcp", host: "v6only", network: "tcp", wantIP: "fd7a:115c:a1e0::3", wantOK: true},
+		{name: "v6only_tcp4_miss", host: "v6only", network: "tcp4", wantOK: false},
+		{name: "extra_record", host: "svc-foo.tail-scale.ts.net", network: "tcp", wantIP: "100.11.22.33", wantOK: true},
+		{name: "extra_record_tcp6_miss", host: "svc-foo.tail-scale.ts.net", network: "tcp6", wantOK: false},
+		{name: "unknown", host: "nope", network: "tcp", wantOK: false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			ip, ok := b.resolveMagicDNS(tt.host, tt.network)
+			if ok != tt.wantOK {
+				t.Fatalf("resolveMagicDNS(%q, %q): ok=%v, want %v", tt.host, tt.network, ok, tt.wantOK)
+			}
+			if ok && ip.String() != tt.wantIP {
+				t.Fatalf("resolveMagicDNS(%q, %q): ip=%v, want %v", tt.host, tt.network, ip, tt.wantIP)
+			}
+		})
+	}
+}