[management, client, proxy] Follow-up fixes for private reverse-proxy services (#6268)

* fix(proxy): gate tunnel-peer fast-path on inbound listener marker

forwardWithTunnelPeer previously accepted any RFC1918 / ULA / CGNAT
source IP, so a public client whose address happened to fall in those
ranges could bypass the configured operator auth scheme by colliding
with a known tunnel IP. The fast-path is now gated on
TunnelLookupFromContext(r.Context()) being present — that context value
is attached only by the per-account inbound (overlay) listener, so the
host-facing listener never enters this branch.

Tests updated to reflect the new requirement: requests that don't
carry the inbound marker now fall through to the regular auth flow.

* fix(proxy): harden inbound listener resource + startup-ctx handling

Three correctness fixes on the per-account inbound path, with tests:

- Close the logrus ErrorLog PipeWriter on tearDown. WriterLevel hands
  back an *io.PipeWriter backed by a pipe + scanner goroutine that the
  caller owns; the two writers per account (https + plain) were never
  closed, leaking the pipe and goroutine on every teardown.
- Run the post-Start hooks on context.Background(). runClientStartup
  is launched in a goroutine from AddPeer and was inheriting the
  caller's request-scoped ctx, so a cancelled request could abort the
  inbound bring-up or fail the management status notification. The
  tail is split into notifyClientReady so the contract is testable.

Tests cover the PipeWriter close behaviour and assert the readyHandler
+ NotifyStatus calls receive a non-cancelled background context.

* feat(proxy): short-circuit peer-own-target loops with 421

When a peer that hosts the target of a private service dials its own
service URL the request was being looped through the proxy and back
over WireGuard to the same peer — twice the WG round-trip for no
benefit, with no signal to the caller that something was wrong.

Add isSelfTargetLoop to ReverseProxy.ServeHTTP: when the request
arrived on the per-account overlay listener (IsOverlayOrigin) and the
source tunnel IP matches the target host, refuse the request with 421
Misdirected Request and a body pointing the operator at the backend
directly.

The gate is scoped to overlay origin so requests on the public
listener that happen to share a source IP with the target host are
forwarded normally.

* fix(management): private-service validation + tunnel-IP lookup semantics

- Require an explicit port for L4 cluster targets. validateL4Target
  exempted TargetTypeCluster from the port check, but buildPathMappings
  serializes every L4 target via net.JoinHostPort(host, port) — port=0
  shipped a ":0" upstream. Cluster targets use the same Host/Port
  fields, so the same requirement applies.
- GetPeerByIP returns NotFound on a tunnel-IP miss instead of mapping
  every error to Internal. The proxy's ValidateTunnelPeer probes IPs
  that legitimately aren't in the roster; the miss is expected and now
  distinguishable from a real store failure.
- Thread ctx into getClusterCapability's gorm query so a cancelled
  request doesn't keep the store busy.

Tests updated for the L4-cluster port requirement and the GetPeerByIP
NotFound path.

* fix(client): include offlinePeers in PeerStateByIP lookup

ReplaceOfflinePeers moves peers into d.offlinePeers but PeerStateByIP
only scanned d.peers. Callers (the local DNS filter via
localPeerConnectivity, embed.Client.IdentityForIP used by the
proxy's tunnel-peer validator) were treating known-but-offline peers
as unknown, which:

- causes the DNS filter to keep returning records pointing at peers
  that have no live tunnel, AND
- makes the proxy's local-roster check deny a request from such a
  peer rather than letting the cached management RPC carry the
  authorisation decision.

Search both slices in PeerStateByIP. Adds a unit test for the IPv4
and IPv6 offline-match paths.

* fix(rest): reject empty Delete path params in reverse-proxy clients

ReverseProxyClustersAPI.Delete and ReverseProxyTokensAPI.Delete passed
the path parameter into url.PathEscape without an empty check.
PathEscape("") returns "" which collapses the request onto the
collection endpoint ("/api/reverse-proxies/clusters/" /
"/api/reverse-proxies/proxy-tokens/"), so a caller bug delete with no
id reached a routable URL with surprising semantics (typically 405).

Short-circuit with a typed error before the request is built. Tests
mount a handler on the collection path that fails the test if hit, so
the regression is impossible to reintroduce silently.

* chore(api,ci,docs,test): private-service schema, proto-check, fixups

Non-functional cleanups and contract/CI hardening around the
private-service work:

API schema (openapi.yml):
- Require a non-empty access_groups and mode=http when private=true,
  on both Service and ServiceRequest, mirroring
  validatePrivateRequirements. mode stays optional-but-constrained
  (empty defaults to http server-side), matching runtime.

CI (proto-version-check.yml):
- Cover renamed .pb.go files (read base via previous_filename).
- Match protoc-gen-go-grpc version headers (optional "- " prefix and
  -gen-go-grpc suffix) so grpc-generated files are in scope.

Docs / comments:
- Reword Config field docs to say defaults are applied at Server.Start
  (initDefaults), not New.
- Rename the obsolete --private-inbound flag to --private across
  comments and the proto doc.

Pre-existing test fixups surfaced by review:
- Repair the integration-tagged validate_session_test.go (SignToken
  signature growth + new Manager interface methods).
- Fix the CI-skip boolean precedence so Windows isn't skipped
  unconditionally.
- Guard the router.HTTPListener type assertion with comma-ok.

* fix(proxy): background ctx for already-started AddPeer notification

The earlier ctx fix covered the async runClientStartup path but missed
the synchronous branch: when a service is added to an already-started
client, AddPeer called NotifyStatus with the caller's request-scoped
ctx. A cancelled request/stream could drop the connected notification
to management. Use context.Background() here too, matching
notifyClientReady.

Extends TestNetBird_AddPeer_ExistingStartedClient_NotifiesStatus to
pass a pre-cancelled caller ctx and assert the notification still ran
on a non-cancelled context.

* use the cmd context for roundtripper

proxy/inbound.go

@@ -5,6 +5,7 @@ import (
 	"crypto/tls"
 	"errors"
 	"fmt"
+	"io"
 	stdlog "log"
 	"net"
 	"net/http"
@@ -42,7 +43,7 @@ const privateInboundPortHTTPS = 443
 const privateInboundPortHTTP = 80
 
 // inboundManager wires per-account inbound listeners into the proxy
-// pipeline when --private-inbound is enabled. When disabled the manager
+// pipeline when --private is enabled. When disabled the manager
 // is nil and every method on *Server that touches it short-circuits.
 type inboundManager struct {
 	logger    *log.Logger
@@ -55,15 +56,18 @@ type inboundManager struct {
 }
 
 // inboundEntry owns the listeners, router and HTTP servers for a single
-// account's embedded netstack.
+// account's embedded netstack. errorLogWriters retain the logrus pipe
+// writers backing each http.Server's ErrorLog so tearDown can close
+// them — otherwise the pipe + its scanner goroutine leak per account.
 type inboundEntry struct {
-	router        *nbtcp.Router
-	tlsListener   net.Listener
-	plainListener net.Listener
-	httpsServer   *http.Server
-	httpServer    *http.Server
-	cancel        context.CancelFunc
-	wg            sync.WaitGroup
+	router          *nbtcp.Router
+	tlsListener     net.Listener
+	plainListener   net.Listener
+	httpsServer     *http.Server
+	httpServer      *http.Server
+	errorLogWriters []*io.PipeWriter
+	cancel          context.CancelFunc
+	wg              sync.WaitGroup
 }
 
 // pendingInboundRoute holds a route that arrived before the account's
@@ -147,30 +151,34 @@ func (m *inboundManager) bringUp(ctx context.Context, accountID types.AccountID,
 		return types.WithOverlayOrigin(ctx)
 	}
 
+	httpsErrLog, httpsErrW := newInboundErrorLog(m.logger, "https", accountID)
+	httpErrLog, httpErrW := newInboundErrorLog(m.logger, "http", accountID)
+
 	httpsServer := &http.Server{
 		Handler:           scopedHandler,
 		TLSConfig:         m.tlsConfig,
 		ReadHeaderTimeout: httpInboundReadHeaderTimeout,
 		IdleTimeout:       httpInboundIdleTimeout,
-		ErrorLog:          newInboundErrorLog(m.logger, "https", accountID),
+		ErrorLog:          httpsErrLog,
 		ConnContext:       markOverlayOrigin,
 	}
 	httpServer := &http.Server{
 		Handler:           scopedHandler,
 		ReadHeaderTimeout: httpInboundReadHeaderTimeout,
 		IdleTimeout:       httpInboundIdleTimeout,
-		ErrorLog:          newInboundErrorLog(m.logger, "http", accountID),
+		ErrorLog:          httpErrLog,
 		ConnContext:       markOverlayOrigin,
 	}
 
 	runCtx, cancel := context.WithCancel(ctx)
 	entry := &inboundEntry{
-		router:        router,
-		tlsListener:   tlsListener,
-		plainListener: plainListener,
-		httpsServer:   httpsServer,
-		httpServer:    httpServer,
-		cancel:        cancel,
+		router:          router,
+		tlsListener:     tlsListener,
+		plainListener:   plainListener,
+		httpsServer:     httpsServer,
+		httpServer:      httpServer,
+		errorLogWriters: []*io.PipeWriter{httpsErrW, httpErrW},
+		cancel:          cancel,
 	}
 
 	entry.wg.Add(1)
@@ -237,6 +245,14 @@ func (m *inboundManager) tearDown(accountID types.AccountID, entry *inboundEntry
 		m.logger.Debugf("close per-account plain listener: %v", err)
 	}
 	entry.wg.Wait()
+	// Close the ErrorLog pipes only after the http.Servers have fully
+	// stopped so any straggling stdlib write doesn't race with the
+	// close. Each writer also tears down the logrus scanner goroutine.
+	for _, w := range entry.errorLogWriters {
+		if err := w.Close(); err != nil {
+			m.logger.Debugf("close per-account inbound error log writer: %v", err)
+		}
+	}
 }
 
 // AddRoute records an SNI/host route on the account's per-account router.
@@ -374,7 +390,7 @@ func (m *inboundManager) ListenerInfo(accountID types.AccountID) (InboundListene
 }
 
 // Snapshot returns the inbound listener state for every account that has
-// a live listener at call time. Empty when --private-inbound is off or
+// a live listener at call time. Empty when --private is off or
 // no accounts have come up yet.
 func (m *inboundManager) Snapshot() map[types.AccountID]InboundListenerInfo {
 	if m == nil {
@@ -497,7 +513,7 @@ func accountTunnelLookup(client *embed.Client) auth.TunnelLookupFunc {
 // peerstore lookup to every request's context before delegating to next.
 // Calling on the host-level listener is a no-op because that path never
 // installs this wrapper, so the existing behaviour stays byte-for-byte
-// identical when --private-inbound is off or the request didn't arrive
+// identical when --private is off or the request didn't arrive
 // on a per-account listener.
 func withTunnelLookup(next http.Handler, lookup auth.TunnelLookupFunc) http.Handler {
 	if lookup == nil {
@@ -538,10 +554,14 @@ func (a inboundDebugAdapter) InboundListeners() map[types.AccountID]debug.Inboun
 }
 
 // newInboundErrorLog routes a per-account http.Server's stdlib error
-// stream through logrus at warn level.
-func newInboundErrorLog(logger *log.Logger, scheme string, accountID types.AccountID) *stdlog.Logger {
-	return stdlog.New(logger.WithFields(log.Fields{
+// stream through logrus at warn level. The returned PipeWriter must be
+// closed by the caller (tearDown) once the http.Server has shut down —
+// otherwise the pipe and its scanner goroutine leak per account, see
+// logrus.Entry.WriterLevel.
+func newInboundErrorLog(logger *log.Logger, scheme string, accountID types.AccountID) (*stdlog.Logger, *io.PipeWriter) {
+	w := logger.WithFields(log.Fields{
 		"inbound-http": scheme,
 		"account_id":   accountID,
-	}).WriterLevel(log.WarnLevel), "", 0)
+	}).WriterLevel(log.WarnLevel)
+	return stdlog.New(w, "", 0), w
 }