From ae8641735df2844b4d5d0abcd25c074d297a013d Mon Sep 17 00:00:00 2001
From: Jordan Whited <jordan@tailscale.com>
Date: Wed, 9 Jul 2025 15:17:51 -0700
Subject: [PATCH] cmd/tailscale/cli,ipn/ipnstate,wgengine/magicsock: label
 peer-relay (#16510)

Updates tailscale/corp#30033

Signed-off-by: Jordan Whited <jordan@tailscale.com>
---
 cmd/tailscale/cli/status.go     |  4 +++-
 ipn/ipnstate/ipnstate.go        | 10 +++++++---
 wgengine/magicsock/endpoint.go  |  9 +++++----
 wgengine/magicsock/magicsock.go |  2 +-
 4 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/cmd/tailscale/cli/status.go b/cmd/tailscale/cli/status.go
index e4dccc247..85679a7de 100644
--- a/cmd/tailscale/cli/status.go
+++ b/cmd/tailscale/cli/status.go
@@ -183,10 +183,12 @@ func runStatus(ctx context.Context, args []string) error {
 			} else if ps.ExitNodeOption {
 				f("offers exit node; ")
 			}
-			if relay != "" && ps.CurAddr == "" {
+			if relay != "" && ps.CurAddr == "" && ps.PeerRelay == "" {
 				f("relay %q", relay)
 			} else if ps.CurAddr != "" {
 				f("direct %s", ps.CurAddr)
+			} else if ps.PeerRelay != "" {
+				f("peer-relay %s", ps.PeerRelay)
 			}
 			if !ps.Online {
 				f("; offline")
diff --git a/ipn/ipnstate/ipnstate.go b/ipn/ipnstate/ipnstate.go
index 89c6d7e24..fdfd4e334 100644
--- a/ipn/ipnstate/ipnstate.go
+++ b/ipn/ipnstate/ipnstate.go
@@ -251,9 +251,10 @@ type PeerStatus struct {
 	PrimaryRoutes *views.Slice[netip.Prefix] `json:",omitempty"`
 
 	// Endpoints:
-	Addrs   []string
-	CurAddr string // one of Addrs, or unique if roaming
-	Relay   string // DERP region
+	Addrs     []string
+	CurAddr   string // one of Addrs, or unique if roaming
+	Relay     string // DERP region
+	PeerRelay string // peer relay address (ip:port:vni)
 
 	RxBytes        int64
 	TxBytes        int64
@@ -451,6 +452,9 @@ func (sb *StatusBuilder) AddPeer(peer key.NodePublic, st *PeerStatus) {
 	if v := st.Relay; v != "" {
 		e.Relay = v
 	}
+	if v := st.PeerRelay; v != "" {
+		e.PeerRelay = v
+	}
 	if v := st.UserID; v != 0 {
 		e.UserID = v
 	}
diff --git a/wgengine/magicsock/endpoint.go b/wgengine/magicsock/endpoint.go
index 4780c7f37..bfafec5ab 100644
--- a/wgengine/magicsock/endpoint.go
+++ b/wgengine/magicsock/endpoint.go
@@ -1961,10 +1961,11 @@ func (de *endpoint) populatePeerStatus(ps *ipnstate.PeerStatus) {
 	ps.Active = now.Sub(de.lastSendExt) < sessionActiveTimeout
 
 	if udpAddr, derpAddr, _ := de.addrForSendLocked(now); udpAddr.ap.IsValid() && !derpAddr.IsValid() {
-		// TODO(jwhited): if udpAddr.vni.isSet() we are using a Tailscale client
-		//  as a UDP relay; update PeerStatus and its interpretation by
-		//  "tailscale status" to make this clear.
-		ps.CurAddr = udpAddr.String()
+		if udpAddr.vni.isSet() {
+			ps.PeerRelay = udpAddr.String()
+		} else {
+			ps.CurAddr = udpAddr.String()
+		}
 	}
 }
 
diff --git a/wgengine/magicsock/magicsock.go b/wgengine/magicsock/magicsock.go
index 582e74c8b..8743fe9cc 100644
--- a/wgengine/magicsock/magicsock.go
+++ b/wgengine/magicsock/magicsock.go
@@ -3437,7 +3437,7 @@ func (c *Conn) onNodeMutationsUpdate(update NodeMutationsUpdate) {
 	}
 }
 
-// UpdateStatus implements the interface nede by ipnstate.StatusBuilder.
+// UpdateStatus implements the interface needed by ipnstate.StatusBuilder.
 //
 // This method adds in the magicsock-specific information only. Most
 // of the status is otherwise populated by LocalBackend.