all: use math/rand/v2 more

Updates #11058

Signed-off-by: Maisem Ali <maisem@tailscale.com>

cmd/sniproxy/handlers.go

@@ -7,7 +7,7 @@ import (
 	"context"
 	"fmt"
 	"log"
-	"math/rand"
+	"math/rand/v2"
 	"net"
 	"net/netip"
 	"slices"
@@ -47,7 +47,7 @@ func (h *tcpRoundRobinHandler) Handle(c net.Conn) {
 		return netutil.NewOneConnListener(c, nil), nil
 	}
 
-	dest := h.To[rand.Intn(len(h.To))]
+	dest := h.To[rand.IntN(len(h.To))]
 	dial := &tcpproxy.DialProxy{
 		Addr:        fmt.Sprintf("%s:%s", dest, port),
 		DialContext: h.DialContext,

cmd/stund/depaware.txt

@@ -153,7 +153,7 @@ tailscale.com/cmd/stund dependencies: (generated by github.com/tailscale/depawar
         math/big                                                     from crypto/dsa+
         math/bits                                                    from compress/flate+
         math/rand                                                    from math/big+
-        math/rand/v2                                                 from tailscale.com/util/fastuuid
+        math/rand/v2                                                 from tailscale.com/util/fastuuid+
         mime                                                         from github.com/prometheus/common/expfmt+
         mime/multipart                                               from net/http
         mime/quotedprintable                                         from mime/multipart

cmd/stunstamp/stunstamp.go

@@ -15,7 +15,7 @@ import (
 	"io"
 	"log"
 	"math"
-	"math/rand"
+	"math/rand/v2"
 	"net"
 	"net/http"
 	"net/netip"
@@ -151,7 +151,7 @@ func probe(meta nodeMeta, conn io.ReadWriteCloser, fn measureFn) (*time.Duration
 		Port: 3478,
 	}
 
-	time.Sleep(time.Millisecond * time.Duration(rand.Intn(200))) // jitter across tx
+	time.Sleep(rand.N(200 * time.Millisecond)) // jitter across tx
 	rtt, err := fn(conn, ua)
 	if err != nil {
 		if isTemporaryOrTimeoutErr(err) {

cmd/tailscale/depaware.txt

@@ -277,6 +277,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
         math/big                                                     from crypto/dsa+
         math/bits                                                    from compress/flate+
         math/rand                                                    from github.com/mdlayher/netlink+
+        math/rand/v2                                                 from tailscale.com/derp+
         mime                                                         from golang.org/x/oauth2/internal+
         mime/multipart                                               from net/http
         mime/quotedprintable                                         from mime/multipart

cmd/tailscaled/depaware.txt

@@ -529,7 +529,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         math/big                                                     from crypto/dsa+
         math/bits                                                    from compress/flate+
         math/rand                                                    from github.com/mdlayher/netlink+
-        math/rand/v2                                                 from tailscale.com/util/rands
+        math/rand/v2                                                 from tailscale.com/util/rands+
         mime                                                         from github.com/tailscale/xnet/webdav+
         mime/multipart                                               from net/http+
         mime/quotedprintable                                         from mime/multipart

cmd/tsconnect/wasm/wasm_js.go

@@ -16,7 +16,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"log"
-	"math/rand"
+	"math/rand/v2"
 	"net"
 	"net/http"
 	"net/netip"
@@ -604,7 +604,7 @@ func filterSlice[T any](a []T, f func(T) bool) []T {
 func generateHostname() string {
 	tails := words.Tails()
 	scales := words.Scales()
-	if rand.Int()%2 == 0 {
+	if rand.IntN(2) == 0 {
 		// JavaScript
 		tails = filterSlice(tails, func(s string) bool { return strings.HasPrefix(s, "j") })
 		scales = filterSlice(scales, func(s string) bool { return strings.HasPrefix(s, "s") })
@@ -614,8 +614,8 @@ func generateHostname() string {
 		scales = filterSlice(scales, func(s string) bool { return strings.HasPrefix(s, "a") })
 	}
 
-	tail := tails[rand.Intn(len(tails))]
-	scale := scales[rand.Intn(len(scales))]
+	tail := tails[rand.IntN(len(tails))]
+	scale := scales[rand.IntN(len(scales))]
 	return fmt.Sprintf("%s-%s", tail, scale)
 }