Update dependencies

vendor/tailscale.com/wgengine/magicsock/endpoint.go

@@ -9,6 +9,7 @@ import (
 	"encoding/binary"
 	"errors"
 	"fmt"
+	"iter"
 	"math"
 	"math/rand/v2"
 	"net"
@@ -20,7 +21,6 @@ import (
 	"sync/atomic"
 	"time"
 
-	xmaps "golang.org/x/exp/maps"
 	"golang.org/x/net/ipv4"
 	"golang.org/x/net/ipv6"
 	"tailscale.com/disco"
@@ -33,6 +33,7 @@ import (
 	"tailscale.com/types/logger"
 	"tailscale.com/util/mak"
 	"tailscale.com/util/ringbuffer"
+	"tailscale.com/util/slicesx"
 )
 
 var mtuProbePingSizesV4 []int
@@ -586,7 +587,7 @@ func (de *endpoint) addrForWireGuardSendLocked(now mono.Time) (udpAddr netip.Add
 	needPing := len(de.endpointState) > 1 && now.Sub(oldestPing) > wireguardPingInterval
 
 	if !udpAddr.IsValid() {
-		candidates := xmaps.Keys(de.endpointState)
+		candidates := slicesx.MapKeys(de.endpointState)
 
 		// Randomly select an address to use until we retrieve latency information
 		// and give it a short trustBestAddrUntil time so we avoid flapping between
@@ -947,7 +948,15 @@ func (de *endpoint) send(buffs [][]byte) error {
 	de.mu.Unlock()
 
 	if !udpAddr.IsValid() && !derpAddr.IsValid() {
-		return errNoUDPOrDERP
+		// Make a last ditch effort to see if we have a DERP route for them. If
+		// they contacted us over DERP and we don't know their UDP endpoints or
+		// their DERP home, we can at least assume they're reachable over the
+		// DERP they used to contact us.
+		if rid := de.c.fallbackDERPRegionForPeer(de.publicKey); rid != 0 {
+			derpAddr = netip.AddrPortFrom(tailcfg.DerpMagicIPAddr, uint16(rid))
+		} else {
+			return errNoUDPOrDERP
+		}
 	}
 	var err error
 	if udpAddr.IsValid() {
@@ -960,26 +969,40 @@ func (de *endpoint) send(buffs [][]byte) error {
 			de.noteBadEndpoint(udpAddr)
 		}
 
+		var txBytes int
+		for _, b := range buffs {
+			txBytes += len(b)
+		}
+
+		switch {
+		case udpAddr.Addr().Is4():
+			de.c.metrics.outboundPacketsIPv4Total.Add(int64(len(buffs)))
+			de.c.metrics.outboundBytesIPv4Total.Add(int64(txBytes))
+		case udpAddr.Addr().Is6():
+			de.c.metrics.outboundPacketsIPv6Total.Add(int64(len(buffs)))
+			de.c.metrics.outboundBytesIPv6Total.Add(int64(txBytes))
+		}
+
 		// TODO(raggi): needs updating for accuracy, as in error conditions we may have partial sends.
 		if stats := de.c.stats.Load(); err == nil && stats != nil {
-			var txBytes int
-			for _, b := range buffs {
-				txBytes += len(b)
-			}
-			stats.UpdateTxPhysical(de.nodeAddr, udpAddr, txBytes)
+			stats.UpdateTxPhysical(de.nodeAddr, udpAddr, len(buffs), txBytes)
 		}
 	}
 	if derpAddr.IsValid() {
 		allOk := true
+		var txBytes int
 		for _, buff := range buffs {
-			ok, _ := de.c.sendAddr(derpAddr, de.publicKey, buff)
-			if stats := de.c.stats.Load(); stats != nil {
-				stats.UpdateTxPhysical(de.nodeAddr, derpAddr, len(buff))
-			}
+			const isDisco = false
+			ok, _ := de.c.sendAddr(derpAddr, de.publicKey, buff, isDisco)
+			txBytes += len(buff)
 			if !ok {
 				allOk = false
 			}
 		}
+
+		if stats := de.c.stats.Load(); stats != nil {
+			stats.UpdateTxPhysical(de.nodeAddr, derpAddr, len(buffs), txBytes)
+		}
 		if allOk {
 			return nil
 		}
@@ -1344,7 +1367,7 @@ func (de *endpoint) updateFromNode(n tailcfg.NodeView, heartbeatDisabled bool, p
 		})
 		de.resetLocked()
 	}
-	if n.DERP() == "" {
+	if n.HomeDERP() == 0 {
 		if de.derpAddr.IsValid() {
 			de.debugUpdates.Add(EndpointChange{
 				When: time.Now(),
@@ -1354,7 +1377,7 @@ func (de *endpoint) updateFromNode(n tailcfg.NodeView, heartbeatDisabled bool, p
 		}
 		de.derpAddr = netip.AddrPort{}
 	} else {
-		newDerp, _ := netip.ParseAddrPort(n.DERP())
+		newDerp := netip.AddrPortFrom(tailcfg.DerpMagicIPAddr, uint16(n.HomeDERP()))
 		if de.derpAddr != newDerp {
 			de.debugUpdates.Add(EndpointChange{
 				When: time.Now(),
@@ -1370,20 +1393,18 @@ func (de *endpoint) updateFromNode(n tailcfg.NodeView, heartbeatDisabled bool, p
 }
 
 func (de *endpoint) setEndpointsLocked(eps interface {
-	Len() int
-	At(i int) netip.AddrPort
+	All() iter.Seq2[int, netip.AddrPort]
 }) {
 	for _, st := range de.endpointState {
 		st.index = indexSentinelDeleted // assume deleted until updated in next loop
 	}
 
 	var newIpps []netip.AddrPort
-	for i := range eps.Len() {
+	for i, ipp := range eps.All() {
 		if i > math.MaxInt16 {
 			// Seems unlikely.
 			break
 		}
-		ipp := eps.At(i)
 		if !ipp.IsValid() {
 			de.c.logf("magicsock: bogus netmap endpoint from %v", eps)
 			continue