cmd/tailscale: change formatting of "tailscale status"

* show DNS name over hostname, removing domain's common MagicDNS suffix.
  only show hostname if there's no DNS name.
  but still show shared devices' MagicDNS FQDN.

* remove nerdy low-level details by default: endpoints, DERP relay,
  public key.  They're available in JSON mode still for those who need
  them.

* only show endpoint or DERP relay when it's active with the goal of
  making debugging easier. (so it's easier for users to understand
  what's happening) The asterisks are gone.

* remove Tx/Rx numbers by default for idle peers; only show them when
  there's traffic.

* include peers' owner login names

* add CLI option to not show peers (matching --self=true, --peers= also
  defaults to true)

* sort by DNS/host name, not public key

* reorder columns

wgengine/tsdns/tsdns.go

@@ -17,6 +17,7 @@ import (
 	dns "golang.org/x/net/dns/dnsmessage"
 	"inet.af/netaddr"
 	"tailscale.com/types/logger"
+	"tailscale.com/util/dnsname"
 )
 
 // maxResponseBytes is the maximum size of a response from a Resolver.
@@ -195,7 +196,7 @@ func (r *Resolver) Resolve(domain string, tp dns.Type) (netaddr.IP, dns.RCode, e
 
 	anyHasSuffix := false
 	for _, suffix := range dnsMap.rootDomains {
-		if NameHasSuffix(domain, suffix) {
+		if dnsname.HasSuffix(domain, suffix) {
 			anyHasSuffix = true
 			break
 		}
@@ -616,12 +617,3 @@ func (r *Resolver) respond(query []byte) ([]byte, error) {
 
 	return marshalResponse(resp)
 }
-
-// NameHasSuffix reports whether the provided DNS name ends with the
-// component(s) in suffix, ignoring any trailing dots.
-func NameHasSuffix(name, suffix string) bool {
-	name = strings.TrimSuffix(name, ".")
-	suffix = strings.TrimSuffix(suffix, ".")
-	nameBase := strings.TrimSuffix(name, suffix)
-	return len(nameBase) < len(name) && strings.HasSuffix(nameBase, ".")
-}

wgengine/tsdns/tsdns_test.go

@@ -797,24 +797,3 @@ func TestMarshalResponseFormatError(t *testing.T) {
 	}
 	t.Logf("response: %q", v)
 }
-
-func TestNameHasSuffix(t *testing.T) {
-	tests := []struct {
-		name, suffix string
-		want         bool
-	}{
-		{"foo.com", "com", true},
-		{"foo.com.", "com", true},
-		{"foo.com.", "com.", true},
-
-		{"", "", false},
-		{"foo.com.", "", false},
-		{"foo.com.", "o.com", false},
-	}
-	for _, tt := range tests {
-		got := NameHasSuffix(tt.name, tt.suffix)
-		if got != tt.want {
-			t.Errorf("NameHasSuffix(%q, %q) = %v; want %v", tt.name, tt.suffix, got, tt.want)
-		}
-	}
-}