Update to Go 1.25

.github/workflows/e2e.yml

@@ -14,7 +14,7 @@ on:
   workflow_dispatch:
 
 env:
-  GO_VERSION: "1.24"
+  GO_VERSION: "1.25"
   K8S_VERSION: "v1.34.0"
   KIND_VERSION: "v0.30.0"
   KIND_CLUSTER_NAME: "kindnet"

.github/workflows/test.yaml

@@ -7,7 +7,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        go-version: [1.24.x]
+        go-version: [1.25.x]
     runs-on: ubuntu-latest
     steps:
     - uses: actions/setup-go@v6

.golangci.yaml

@@ -1,24 +1,21 @@
 # Copyright 2025 Antonio Ojea
 # SPDX-License-Identifier: Apache-2.0
+version: 2
 
 run:
   timeout: 30m
   tests: false # TODO lint tests too
 
 linters:
-  disable-all: true
+  default: none
   enable:
     - gocritic
-    - gosimple
     - govet
     - errcheck
     - ineffassign
     - staticcheck
-    - stylecheck
-    - typecheck
 
 formatters:
-  disable-all: true
   enable:
     - goimports
     - gofmt

cmd/kindnetd/main.go

@@ -452,7 +452,12 @@ func checkHTTP(address string) bool {
 	if err != nil {
 		return false
 	}
-	defer resp.Body.Close()
+
+	defer func() {
+		if err := resp.Body.Close(); err != nil {
+			klog.ErrorS(err, "failed to close response body")
+		}
+	}()
 
 	_, err = io.ReadAll(resp.Body)
 	if err != nil {

go.mod

@@ -1,8 +1,6 @@
 module sigs.k8s.io/kindnet
 
-go 1.24.3
-
-toolchain go1.24.7
+go 1.25
 
 require (
 	github.com/aws/aws-sdk-go-v2 v1.41.1

hack/lint.sh

@@ -19,7 +19,7 @@ set -o nounset
 set -o pipefail
 
 REPO_ROOT=$(dirname "${BASH_SOURCE[0]}")/..
-VERSION=v1.64.7
+VERSION=v2.7.2
 
 cd $REPO_ROOT
 docker run --rm -v $(pwd):/app -w /app golangci/golangci-lint:${VERSION} golangci-lint run -v

pkg/conntrack/conntrack.go

@@ -58,7 +58,12 @@ func StartConntrackMetricsAgent(ctx context.Context) error {
 	if err != nil {
 		return err
 	}
-	defer statsConn.Close()
+
+	defer func() {
+		if err := statsConn.Close(); err != nil {
+			klog.V(4).Infof("failed to close conntrack stats conn: %v", err)
+		}
+	}()
 
 	// Start a goroutine to process all conntrack stats.
 	go func() {
@@ -111,7 +116,13 @@ func StartConntrackMetricsAgent(ctx context.Context) error {
 	if err != nil {
 		return err
 	}
-	defer eventsConn.Close()
+
+	defer func() {
+		if err := eventsConn.Close(); err != nil {
+			klog.V(4).Infof("failed to close conntrack events conn: %v", err)
+		}
+	}()
+
 	// reference https://lore.kernel.org/netdev/49C789F4.4050906@trash.net/T/#mfa68b0c462d1342869f4a2a152285910220f72bc
 	err = eventsConn.SetOption(netlink.BroadcastError, true)
 	if err != nil {

pkg/dnscache/agent.go

@@ -177,7 +177,12 @@ func (d *DNSCacheAgent) Run(ctx context.Context) error {
 		logger.Info("could not open nfqueue socket", "error", err)
 		return err
 	}
-	defer nf.Close()
+
+	defer func() {
+		if err := nf.Close(); err != nil {
+			klog.V(4).Infof("failed to close nfqueue: %v", err)
+		}
+	}()
 
 	d.nfq = nf
 
@@ -271,8 +276,12 @@ func printNfnetlinkQueueStats() {
 		klog.Infof("can not get nfqueue stats: %v", err)
 		return
 	}
-	defer f.Close()
 
+	defer func() {
+		if err := f.Close(); err != nil {
+			klog.V(4).Infof("failed to close nfqueue stats file: %v", err)
+		}
+	}()
 	reader := io.LimitReader(f, maxBufferSize)
 
 	scanner := bufio.NewScanner(reader)

pkg/dnscache/connection_pool.go

@@ -113,7 +113,7 @@ func (p *ConnectionPool) Put(conn *net.TCPConn) {
 		p.mu.Lock()
 		defer p.mu.Unlock()
 		p.activeConns--
-		conn.Close()
+		_ = conn.Close()
 	}
 }
 
@@ -138,6 +138,6 @@ func (p *ConnectionPool) newConnection(address string) (*net.TCPConn, error) {
 // Close closes all connections in the pool.
 func (p *ConnectionPool) Close() {
 	for conn := range p.conns {
-		conn.Close()
+		_ = conn.Close()
 	}
 }

pkg/dnscache/node.go

@@ -93,7 +93,12 @@ func parseResolvConf(resolvPath string) (nameservers []string, searches []string
 		klog.ErrorS(err, "Could not open resolv conf file.", "path", resolvPath)
 		return nil, nil, nil, err
 	}
-	defer f.Close()
+
+	defer func() {
+		if cerr := f.Close(); cerr != nil {
+			klog.V(4).Infof("failed to close resolv conf file %s: %v", resolvPath, cerr)
+		}
+	}()
 
 	file, err := utilio.ReadAtMost(f, maxResolvConfLength)
 	if err != nil {

pkg/nat64/proxy.go

@@ -92,8 +92,11 @@ func (n *NAT64Agent) Run(ctx context.Context) error {
 	if err != nil {
 		return err
 	}
-	defer conn.Close()
-
+	defer func() {
+		if err := conn.Close(); err != nil {
+			klog.V(4).Infof("failed to close UDP listener: %v", err)
+		}
+	}()
 	klog.V(2).Infof("listening on UDP %s", conn.LocalAddr().String())
 	_, port, err := net.SplitHostPort(conn.LocalAddr().String())
 	if err != nil {
@@ -138,7 +141,12 @@ func (n *NAT64Agent) Run(ctx context.Context) error {
 	if err != nil {
 		return err
 	}
-	defer tcpListener.Close()
+
+	defer func() {
+		if err := tcpListener.Close(); err != nil {
+			klog.V(4).Infof("failed to close TCP listener: %v", err)
+		}
+	}()
 
 	klog.V(2).Infof("listening on TCP %s", tcpListener.Addr().String())
 	_, port, err = net.SplitHostPort(tcpListener.Addr().String())
@@ -341,8 +349,11 @@ func CleanRules() {
 }
 
 func handleTCPConn(conn net.Conn) {
-	defer conn.Close()
-
+	defer func() {
+		if err := conn.Close(); err != nil {
+			klog.V(4).Infof("failed to close TCP connection: %v", err)
+		}
+	}()
 	host, port, err := net.SplitHostPort(conn.LocalAddr().String())
 	if err != nil {
 		klog.V(2).Infof("Failed to get remote address [%s]: %v", conn.LocalAddr().String(), err)
@@ -363,8 +374,11 @@ func handleTCPConn(conn net.Conn) {
 		klog.V(2).Infof("Failed to connect to original destination [%s]: %s", conn.LocalAddr().String(), err)
 		return
 	}
-	defer remoteConn.Close()
-
+	defer func() {
+		if err := conn.Close(); err != nil {
+			klog.V(4).Infof("failed to close remote TCP connection: %v", err)
+		}
+	}()
 	var streamWait sync.WaitGroup
 	streamWait.Add(2)
 
@@ -389,15 +403,18 @@ func handleUDPConn(origAddr *net.UDPAddr, dstAddr *net.UDPAddr, data []byte) {
 	// assume 64:ff9b::/96 and last 4 digits
 	// https://www.rfc-editor.org/rfc/rfc6052.html
 	ip4 := ip4in6[12:16]
-	dstV4Addr := fmt.Sprintf("%s:%d", ip4.String(), dstAddr.Port)
+	dstV4Addr := net.JoinHostPort(ip4.String(), strconv.Itoa(dstAddr.Port))
 	klog.V(4).Infof("Connecting to %s", dstV4Addr)
 	remoteConn, err := net.Dial("udp", dstV4Addr)
 	if err != nil {
 		klog.V(2).Infof("Failed to connect to original destination %s: %v", dstV4Addr, err)
 		return
 	}
-	defer remoteConn.Close()
-
+	defer func() {
+		if err := remoteConn.Close(); err != nil {
+			klog.V(4).Infof("failed to close remote TCP connection: %v", err)
+		}
+	}()
 	n, err := remoteConn.Write(data)
 	if err != nil {
 		klog.V(2).Infof("Fail to write to remote %s: %s", remoteConn.RemoteAddr(), err)

pkg/network/ethtool.go

@@ -20,6 +20,8 @@ import (
 	"fmt"
 	"syscall"
 	"unsafe"
+
+	"k8s.io/klog/v2"
 )
 
 const (
@@ -54,8 +56,12 @@ func ethtool(iface string, cmd, val uint32) (retval uint32, err error) {
 	if err != nil {
 		return 0, err
 	}
-	defer syscall.Close(socket)
 
+	defer func() {
+		if err := syscall.Close(socket); err != nil {
+			klog.V(4).Infof("failed to close ethtool socket: %v", err)
+		}
+	}()
 	// prepare ethtool request
 	value := ethtoolValue{cmd, val}
 	request := ifreq{Data: uintptr(unsafe.Pointer(&value))}

pkg/nflog/nflog.go

@@ -62,7 +62,12 @@ func (n *NFLogAgent) Run(ctx context.Context) error {
 	if err != nil {
 		return fmt.Errorf("could not open nflog socket: %v", err)
 	}
-	defer nf.Close()
+
+	defer func() {
+		if err := nf.Close(); err != nil {
+			klog.V(4).Infof("failed to close nflog socket: %v", err)
+		}
+	}()
 
 	// Avoid receiving ENOBUFS errors.
 	if err := nf.SetOption(netlink.NoENOBUFS, true); err != nil {

pkg/node/cni.go

@@ -76,7 +76,13 @@ func WriteCNIConfig(ranges []string) (err error) {
 
 	f1, err := os.Open(cniFile)
 	if err == nil {
-		defer f1.Close()
+
+		defer func() {
+			if cerr := f1.Close(); cerr != nil {
+				klog.V(4).Infof("failed to close %s: %v", cniFile, cerr)
+			}
+		}()
+
 		// Calculate the MD5 checksum of the existing file
 		h1 := md5.New()
 		if _, err := io.Copy(h1, f1); err != nil {