all: use iterators over slice views more

This gets close to all of the remaining ones.

Updates #12912

Change-Id: I9c672bbed2654a6c5cab31e0cbece6c107d8c6fa
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

cmd/tsconnect/wasm/wasm_js.go

@@ -272,8 +272,8 @@ func (i *jsIPN) run(jsCallbacks js.Value) {
 						name = p.Hostinfo().Hostname()
 					}
 					addrs := make([]string, p.Addresses().Len())
-					for i := range p.Addresses().Len() {
+					for i, ap := range p.Addresses().All() {
-						addrs[i] = p.Addresses().At(i).Addr().String()
+						addrs[i] = ap.Addr().String()
 					}
 					return jsNetMapPeerNode{
 						jsNetMapNode: jsNetMapNode{
@@ -589,8 +589,8 @@ func mapSlice[T any, M any](a []T, f func(T) M) []M {
 
 func mapSliceView[T any, M any](a views.Slice[T], f func(T) M) []M {
 	n := make([]M, a.Len())
-	for i := range a.Len() {
+	for i, v := range a.All() {
-		n[i] = f(a.At(i))
+		n[i] = f(v)
 	}
 	return n
 }

ipn/ipnlocal/drive.go

@@ -354,9 +354,8 @@ func (b *LocalBackend) driveRemotesFromPeers(nm *netmap.NetworkMap) []*drive.Rem
 
 				// Check that the peer is allowed to share with us.
 				addresses := peer.Addresses()
-				for i := range addresses.Len() {
+				for _, p := range addresses.All() {
-					addr := addresses.At(i)
+					capsMap := b.PeerCaps(p.Addr())
-					capsMap := b.PeerCaps(addr.Addr())
 					if capsMap.HasCapability(tailcfg.PeerCapabilityTaildriveSharer) {
 						return true
 					}

ipn/ipnlocal/local.go

@@ -1811,8 +1811,7 @@ func setExitNodeID(prefs *ipn.Prefs, nm *netmap.NetworkMap, lastSuggestedExitNod
 	}
 
 	for _, peer := range nm.Peers {
-		for i := range peer.Addresses().Len() {
+		for _, addr := range peer.Addresses().All() {
-			addr := peer.Addresses().At(i)
 			if !addr.IsSingleIP() || addr.Addr() != prefs.ExitNodeIP {
 				continue
 			}
@@ -4997,8 +4996,8 @@ func (b *LocalBackend) enterStateLockedOnEntry(newState ipn.State, unlock unlock
 	case ipn.Running:
 		var addrStrs []string
 		addrs := netMap.GetAddresses()
-		for i := range addrs.Len() {
+		for _, p := range addrs.All() {
-			addrStrs = append(addrStrs, addrs.At(i).Addr().String())
+			addrStrs = append(addrStrs, p.Addr().String())
 		}
 		systemd.Status("Connected; %s; %s", activeLogin, strings.Join(addrStrs, " "))
 	case ipn.NoState:
@@ -6089,8 +6088,7 @@ func (b *LocalBackend) SetDNS(ctx context.Context, name, value string) error {
 
 func peerAPIPorts(peer tailcfg.NodeView) (p4, p6 uint16) {
 	svcs := peer.Hostinfo().Services()
-	for i := range svcs.Len() {
+	for _, s := range svcs.All() {
-		s := svcs.At(i)
 		switch s.Proto {
 		case tailcfg.PeerAPI4:
 			p4 = s.Port
@@ -6122,8 +6120,7 @@ func peerAPIBase(nm *netmap.NetworkMap, peer tailcfg.NodeView) string {
 
 	var have4, have6 bool
 	addrs := nm.GetAddresses()
-	for i := range addrs.Len() {
+	for _, a := range addrs.All() {
-		a := addrs.At(i)
 		if !a.IsSingleIP() {
 			continue
 		}
@@ -6145,10 +6142,9 @@ func peerAPIBase(nm *netmap.NetworkMap, peer tailcfg.NodeView) string {
 }
 
 func nodeIP(n tailcfg.NodeView, pred func(netip.Addr) bool) netip.Addr {
-	for i := range n.Addresses().Len() {
+	for _, pfx := range n.Addresses().All() {
-		a := n.Addresses().At(i)
+		if pfx.IsSingleIP() && pred(pfx.Addr()) {
-		if a.IsSingleIP() && pred(a.Addr()) {
+			return pfx.Addr()
-			return a.Addr()
 		}
 	}
 	return netip.Addr{}
@@ -6378,8 +6374,8 @@ func peerCanProxyDNS(p tailcfg.NodeView) bool {
 	// If p.Cap is not populated (e.g. older control server), then do the old
 	// thing of searching through services.
 	services := p.Hostinfo().Services()
-	for i := range services.Len() {
+	for _, s := range services.All() {
-		if s := services.At(i); s.Proto == tailcfg.PeerAPIDNS && s.Port >= 1 {
+		if s.Proto == tailcfg.PeerAPIDNS && s.Port >= 1 {
 			return true
 		}
 	}

ipn/ipnlocal/local_test.go

@@ -3041,12 +3041,10 @@ func deterministicNodeForTest(t testing.TB, want views.Slice[tailcfg.StableNodeI
 		var ret tailcfg.NodeView
 
 		gotIDs := make([]tailcfg.StableNodeID, got.Len())
-		for i := range got.Len() {
+		for i, nv := range got.All() {
-			nv := got.At(i)
 			if !nv.Valid() {
 				t.Fatalf("invalid node at index %v", i)
 			}
-
 			gotIDs[i] = nv.StableID()
 			if nv.StableID() == use {
 				ret = nv

ipn/ipnlocal/network-lock.go

@@ -430,8 +430,7 @@ func (b *LocalBackend) tkaBootstrapFromGenesisLocked(g tkatype.MarshaledAUM, per
 		}
 		bootstrapStateID := fmt.Sprintf("%d:%d", genesis.State.StateID1, genesis.State.StateID2)
 
-		for i := range persist.DisallowedTKAStateIDs().Len() {
+		for _, stateID := range persist.DisallowedTKAStateIDs().All() {
-			stateID := persist.DisallowedTKAStateIDs().At(i)
 			if stateID == bootstrapStateID {
 				return fmt.Errorf("TKA with stateID of %q is disallowed on this node", stateID)
 			}
@@ -572,8 +571,7 @@ func tkaStateFromPeer(p tailcfg.NodeView) ipnstate.TKAPeer {
 		TailscaleIPs: make([]netip.Addr, 0, p.Addresses().Len()),
 		NodeKey:      p.Key(),
 	}
-	for i := range p.Addresses().Len() {
+	for _, addr := range p.Addresses().All() {
-		addr := p.Addresses().At(i)
 		if addr.IsSingleIP() && tsaddr.IsTailscaleIP(addr.Addr()) {
 			fp.TailscaleIPs = append(fp.TailscaleIPs, addr.Addr())
 		}

ipn/ipnlocal/serve.go

@@ -242,8 +242,7 @@ func (b *LocalBackend) updateServeTCPPortNetMapAddrListenersLocked(ports []uint1
 	}
 
 	addrs := nm.GetAddresses()
-	for i := range addrs.Len() {
+	for _, a := range addrs.All() {
-		a := addrs.At(i)
 		for _, p := range ports {
 			addrPort := netip.AddrPortFrom(a.Addr(), p)
 			if _, ok := b.serveListeners[addrPort]; ok {

ipn/ipnlocal/web_client.go

@@ -121,8 +121,8 @@ func (b *LocalBackend) updateWebClientListenersLocked() {
 	}
 
 	addrs := b.netMap.GetAddresses()
-	for i := range addrs.Len() {
+	for _, pfx := range addrs.All() {
-		addrPort := netip.AddrPortFrom(addrs.At(i).Addr(), webClientPort)
+		addrPort := netip.AddrPortFrom(pfx.Addr(), webClientPort)
 		if _, ok := b.webClientListeners[addrPort]; ok {
 			continue // already listening
 		}

net/ipset/ipset.go

@@ -82,8 +82,8 @@ func NewContainsIPFunc(addrs views.Slice[netip.Prefix]) func(ip netip.Addr) bool
 		pathForTest("bart")
 		// Built a bart table.
 		t := &bart.Table[struct{}]{}
-		for i := range addrs.Len() {
+		for _, p := range addrs.All() {
-			t.Insert(addrs.At(i), struct{}{})
+			t.Insert(p, struct{}{})
 		}
 		return bartLookup(t)
 	}
@@ -99,8 +99,8 @@ func NewContainsIPFunc(addrs views.Slice[netip.Prefix]) func(ip netip.Addr) bool
 	// General case:
 	pathForTest("ip-map")
 	m := set.Set[netip.Addr]{}
-	for i := range addrs.Len() {
+	for _, p := range addrs.All() {
-		m.Add(addrs.At(i).Addr())
+		m.Add(p.Addr())
 	}
 	return ipInMap(m)
 }

net/tsaddr/tsaddr.go

@@ -180,8 +180,7 @@ func PrefixIs6(p netip.Prefix) bool { return p.Addr().Is6() }
 // IPv6 /0 route.
 func ContainsExitRoutes(rr views.Slice[netip.Prefix]) bool {
 	var v4, v6 bool
-	for i := range rr.Len() {
+	for _, r := range rr.All() {
-		r := rr.At(i)
 		if r == allIPv4 {
 			v4 = true
 		} else if r == allIPv6 {
@@ -194,8 +193,8 @@ func ContainsExitRoutes(rr views.Slice[netip.Prefix]) bool {
 // ContainsExitRoute reports whether rr contains at least one of IPv4 or
 // IPv6 /0 (exit) routes.
 func ContainsExitRoute(rr views.Slice[netip.Prefix]) bool {
-	for i := range rr.Len() {
+	for _, r := range rr.All() {
-		if rr.At(i).Bits() == 0 {
+		if r.Bits() == 0 {
 			return true
 		}
 	}
@@ -205,8 +204,8 @@ func ContainsExitRoute(rr views.Slice[netip.Prefix]) bool {
 // ContainsNonExitSubnetRoutes reports whether v contains Subnet
 // Routes other than ExitNode Routes.
 func ContainsNonExitSubnetRoutes(rr views.Slice[netip.Prefix]) bool {
-	for i := range rr.Len() {
+	for _, r := range rr.All() {
-		if rr.At(i).Bits() != 0 {
+		if r.Bits() != 0 {
 			return true
 		}
 	}

net/tsdial/dnsmap.go

@@ -42,8 +42,8 @@ func dnsMapFromNetworkMap(nm *netmap.NetworkMap) dnsMap {
 		if dnsname.HasSuffix(nm.Name, suffix) {
 			ret[canonMapKey(dnsname.TrimSuffix(nm.Name, suffix))] = ip
 		}
-		for i := range addrs.Len() {
+		for _, p := range addrs.All() {
-			if addrs.At(i).Addr().Is4() {
+			if p.Addr().Is4() {
 				have4 = true
 			}
 		}
@@ -52,9 +52,8 @@ func dnsMapFromNetworkMap(nm *netmap.NetworkMap) dnsMap {
 		if p.Name() == "" {
 			continue
 		}
-		for i := range p.Addresses().Len() {
+		for _, pfx := range p.Addresses().All() {
-			a := p.Addresses().At(i)
+			ip := pfx.Addr()
-			ip := a.Addr()
 			if ip.Is4() && !have4 {
 				continue
 			}

tsnet/tsnet.go

@@ -433,8 +433,7 @@ func (s *Server) TailscaleIPs() (ip4, ip6 netip.Addr) {
 		return
 	}
 	addrs := nm.GetAddresses()
-	for i := range addrs.Len() {
+	for _, addr := range addrs.All() {
-		addr := addrs.At(i)
 		ip := addr.Addr()
 		if ip.Is6() {
 			ip6 = ip

types/netmap/netmap.go

@@ -279,15 +279,14 @@ func (a *NetworkMap) equalConciseHeader(b *NetworkMap) bool {
 // in nodeConciseEqual in sync.
 func printPeerConcise(buf *strings.Builder, p tailcfg.NodeView) {
 	aip := make([]string, p.AllowedIPs().Len())
-	for i := range aip {
+	for i, a := range p.AllowedIPs().All() {
-		a := p.AllowedIPs().At(i)
+		s := strings.TrimSuffix(a.String(), "/32")
-		s := strings.TrimSuffix(fmt.Sprint(a), "/32")
 		aip[i] = s
 	}
 
-	ep := make([]string, p.Endpoints().Len())
+	epStrs := make([]string, p.Endpoints().Len())
-	for i := range ep {
+	for i, ep := range p.Endpoints().All() {
-		e := p.Endpoints().At(i).String()
+		e := ep.String()
 		// Align vertically on the ':' between IP and port
 		colon := strings.IndexByte(e, ':')
 		spaces := 0
@@ -295,7 +294,7 @@ func printPeerConcise(buf *strings.Builder, p tailcfg.NodeView) {
 			spaces++
 			colon--
 		}
-		ep[i] = fmt.Sprintf("%21v", e+strings.Repeat(" ", spaces))
+		epStrs[i] = fmt.Sprintf("%21v", e+strings.Repeat(" ", spaces))
 	}
 
 	derp := p.DERP()
@@ -316,7 +315,7 @@ func printPeerConcise(buf *strings.Builder, p tailcfg.NodeView) {
 		discoShort,
 		derp,
 		strings.Join(aip, " "),
-		strings.Join(ep, " "))
+		strings.Join(epStrs, " "))
 }
 
 // nodeConciseEqual reports whether a and b are equal for the fields accessed by printPeerConcise.

util/set/slice.go

@@ -67,7 +67,7 @@ func (ss *Slice[T]) Add(vs ...T) {
 
 // AddSlice adds all elements in vs to the set.
 func (ss *Slice[T]) AddSlice(vs views.Slice[T]) {
-	for i := range vs.Len() {
+	for _, v := range vs.All() {
-		ss.Add(vs.At(i))
+		ss.Add(v)
 	}
 }

wgengine/magicsock/debughttp.go

@@ -102,8 +102,7 @@ type kv struct {
 		sort.Slice(ent, func(i, j int) bool { return ent[i].pub.Less(ent[j].pub) })
 
 		peers := map[key.NodePublic]tailcfg.NodeView{}
-		for i := range c.peers.Len() {
+		for _, p := range c.peers.All() {
-			p := c.peers.At(i)
 			peers[p.Key()] = p
 		}
 

wgengine/magicsock/endpoint.go

@@ -9,6 +9,7 @@
 	"encoding/binary"
 	"errors"
 	"fmt"
+	"iter"
 	"math"
 	"math/rand/v2"
 	"net"
@@ -1384,20 +1385,18 @@ func (de *endpoint) updateFromNode(n tailcfg.NodeView, heartbeatDisabled bool, p
 }
 
 func (de *endpoint) setEndpointsLocked(eps interface {
-	Len() int
+	All() iter.Seq2[int, netip.AddrPort]
-	At(i 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

wgengine/magicsock/magicsock.go

@@ -1120,8 +1120,8 @@ func (c *Conn) determineEndpoints(ctx context.Context) ([]tailcfg.Endpoint, erro
 	// re-run.
 	eps = c.endpointTracker.update(time.Now(), eps)
 
-	for i := range c.staticEndpoints.Len() {
+	for _, ep := range c.staticEndpoints.All() {
-		addAddr(c.staticEndpoints.At(i), tailcfg.EndpointExplicitConf)
+		addAddr(ep, tailcfg.EndpointExplicitConf)
 	}
 
 	if localAddr := c.pconn4.LocalAddr(); localAddr.IP.IsUnspecified() {
@@ -2360,16 +2360,14 @@ func (c *Conn) logEndpointCreated(n tailcfg.NodeView) {
 			fmt.Fprintf(w, "derp=%v%s ", regionID, code)
 		}
 
-		for i := range n.AllowedIPs().Len() {
+		for _, a := range n.AllowedIPs().All() {
-			a := n.AllowedIPs().At(i)
 			if a.IsSingleIP() {
 				fmt.Fprintf(w, "aip=%v ", a.Addr())
 			} else {
 				fmt.Fprintf(w, "aip=%v ", a)
 			}
 		}
-		for i := range n.Endpoints().Len() {
+		for _, ep := range n.Endpoints().All() {
-			ep := n.Endpoints().At(i)
 			fmt.Fprintf(w, "ep=%v ", ep)
 		}
 	}))

wgengine/netstack/netstack.go

@@ -643,13 +643,11 @@ func (ns *Impl) UpdateNetstackIPs(nm *netmap.NetworkMap) {
 	newPfx := make(map[netip.Prefix]bool)
 
 	if selfNode.Valid() {
-		for i := range selfNode.Addresses().Len() {
+		for _, p := range selfNode.Addresses().All() {
-			p := selfNode.Addresses().At(i)
 			newPfx[p] = true
 		}
 		if ns.ProcessSubnets {
-			for i := range selfNode.AllowedIPs().Len() {
+			for _, p := range selfNode.AllowedIPs().All() {
-				p := selfNode.AllowedIPs().At(i)
 				newPfx[p] = true
 			}
 		}

wgengine/pendopen.go

@@ -207,8 +207,7 @@ func (e *userspaceEngine) onOpenTimeout(flow flowtrack.Tuple) {
 	ps, found := e.getPeerStatusLite(n.Key())
 	if !found {
 		onlyZeroRoute := true // whether peerForIP returned n only because its /0 route matched
-		for i := range n.AllowedIPs().Len() {
+		for _, r := range n.AllowedIPs().All() {
-			r := n.AllowedIPs().At(i)
 			if r.Bits() != 0 && r.Contains(flow.DstAddr()) {
 				onlyZeroRoute = false
 				break

wgengine/userspace.go

@@ -852,8 +852,7 @@ func (e *userspaceEngine) updateActivityMapsLocked(trackNodes []key.NodePublic,
 // hasOverlap checks if there is a IPPrefix which is common amongst the two
 // provided slices.
 func hasOverlap(aips, rips views.Slice[netip.Prefix]) bool {
-	for i := range aips.Len() {
+	for _, aip := range aips.All() {
-		aip := aips.At(i)
 		if views.SliceContains(rips, aip) {
 			return true
 		}
@@ -1329,9 +1328,9 @@ func (e *userspaceEngine) mySelfIPMatchingFamily(dst netip.Addr) (src netip.Addr
 	if addrs.Len() == 0 {
 		return zero, errors.New("no self address in netmap")
 	}
-	for i := range addrs.Len() {
+	for _, p := range addrs.All() {
-		if a := addrs.At(i); a.IsSingleIP() && a.Addr().BitLen() == dst.BitLen() {
+		if p.IsSingleIP() && p.Addr().BitLen() == dst.BitLen() {
-			return a.Addr(), nil
+			return p.Addr(), nil
 		}
 	}
 	return zero, errors.New("no self address in netmap matching address family")

wgengine/wgcfg/nmcfg/nmcfg.go

@@ -40,8 +40,7 @@ func cidrIsSubnet(node tailcfg.NodeView, cidr netip.Prefix) bool {
 	if !cidr.IsSingleIP() {
 		return true
 	}
-	for i := range node.Addresses().Len() {
+	for _, selfCIDR := range node.Addresses().All() {
-		selfCIDR := node.Addresses().At(i)
 		if cidr == selfCIDR {
 			return false
 		}
@@ -110,8 +109,7 @@ func WGCfg(nm *netmap.NetworkMap, logf logger.Logf, flags netmap.WGConfigFlags,
 		cpeer.V4MasqAddr = peer.SelfNodeV4MasqAddrForThisPeer()
 		cpeer.V6MasqAddr = peer.SelfNodeV6MasqAddrForThisPeer()
 		cpeer.IsJailed = peer.IsJailed()
-		for i := range peer.AllowedIPs().Len() {
+		for _, allowedIP := range peer.AllowedIPs().All() {
-			allowedIP := peer.AllowedIPs().At(i)
 			if allowedIP.Bits() == 0 && peer.StableID() != exitNode {
 				if didExitNodeWarn {
 					// Don't log about both the IPv4 /0 and IPv6 /0.