pkg/proxy: move get kernel version out of ipvs proxier

Signed-off-by: Daman Arora <aroradaman@gmail.com>

pkg/util/kernel/OWNERS

@@ -0,0 +1,8 @@
+# See the OWNERS docs at https://go.k8s.io/owners
+
+reviewers:
+  - sig-network-reviewers
+  - sig-node-reviewers
+approvers:
+  - sig-network-approvers
+  - sig-node-approvers

pkg/util/kernel/constants.go

@@ -0,0 +1,45 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package kernel
+
+// IPLocalReservedPortsNamespacedKernelVersion is the kernel version in which net.ipv4.ip_local_reserved_ports was namespaced(netns).
+// (ref: https://github.com/torvalds/linux/commit/122ff243f5f104194750ecbc76d5946dd1eec934)
+const IPLocalReservedPortsNamespacedKernelVersion = "3.16"
+
+// IPVSConnReuseModeMinSupportedKernelVersion is the minium kernel version supporting net.ipv4.vs.conn_reuse_mode.
+// (ref: https://github.com/torvalds/linux/commit/d752c364571743d696c2a54a449ce77550c35ac5)
+const IPVSConnReuseModeMinSupportedKernelVersion = "4.1"
+
+// TCPKeepAliveTimeNamespacedKernelVersion is the kernel version in which net.ipv4.tcp_keepalive_time was namespaced(netns).
+// (ref: https://github.com/torvalds/linux/commit/13b287e8d1cad951634389f85b8c9b816bd3bb1e)
+const TCPKeepAliveTimeNamespacedKernelVersion = "4.5"
+
+// TCPKeepAliveIntervalNamespacedKernelVersion is the kernel version in which net.ipv4.tcp_keepalive_intvl was namespaced(netns).
+// (ref: https://github.com/torvalds/linux/commit/b840d15d39128d08ed4486085e5507d2617b9ae1)
+const TCPKeepAliveIntervalNamespacedKernelVersion = "4.5"
+
+// TCPKeepAliveProbesNamespacedKernelVersion is the kernel version in which net.ipv4.tcp_keepalive_probes was namespaced(netns).
+// (ref: https://github.com/torvalds/linux/commit/9bd6861bd4326e3afd3f14a9ec8a723771fb20bb)
+const TCPKeepAliveProbesNamespacedKernelVersion = "4.5"
+
+// TCPFinTimeoutNamespacedKernelVersion is the kernel version in which net.ipv4.tcp_fin_timeout was namespaced(netns).
+// (ref: https://github.com/torvalds/linux/commit/1e579caa18b96f9eb18f4f5416658cd15f37c062)
+const TCPFinTimeoutNamespacedKernelVersion = "4.6"
+
+// IPVSConnReuseModeFixedKernelVersion is the kernel version in which net.ipv4.vs.conn_reuse_mode was fixed.
+// (ref: https://github.com/torvalds/linux/commit/35dfb013149f74c2be1ff9c78f14e6a3cd1539d1)
+const IPVSConnReuseModeFixedKernelVersion = "5.9"

pkg/util/kernel/version.go

@@ -0,0 +1,48 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package kernel
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"k8s.io/apimachinery/pkg/util/version"
+)
+
+type readFileFunc func(string) ([]byte, error)
+
+// GetVersion returns currently running kernel version.
+func GetVersion() (*version.Version, error) {
+	return getVersion(os.ReadFile)
+}
+
+// getVersion reads os release file from the give readFile function.
+func getVersion(readFile readFileFunc) (*version.Version, error) {
+	kernelVersionFile := "/proc/sys/kernel/osrelease"
+	fileContent, err := readFile(kernelVersionFile)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read os-release file: %s", err.Error())
+	}
+
+	kernelVersion, err := version.ParseGeneric(strings.TrimSpace(string(fileContent)))
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse kernel version: %s", err.Error())
+	}
+
+	return kernelVersion, nil
+}

pkg/util/kernel/version_test.go

@@ -0,0 +1,82 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package kernel
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"k8s.io/apimachinery/pkg/util/version"
+)
+
+func TestGetVersion(t *testing.T) {
+	testCases := []struct {
+		name         string
+		readFileFunc readFileFunc
+		expected     *version.Version
+		err          error
+	}{
+		{
+			name: "valid os-release file",
+			readFileFunc: func(_ string) ([]byte, error) {
+				return []byte("5.15.0-84-generic"), nil
+			},
+			expected: version.MajorMinor(5, 15),
+		},
+		{
+			name: "valid os-release file",
+			readFileFunc: func(_ string) ([]byte, error) {
+				return []byte("5.4.0-128-generic"), nil
+			},
+			expected: version.MajorMinor(5, 4),
+		},
+		{
+			name: "failed to read os-release file",
+			readFileFunc: func(_ string) ([]byte, error) {
+				return nil, errors.New("open /proc/sys/kernel/osrelease: failed to read file")
+			},
+			err:      errors.New("failed to read os-release file: open /proc/sys/kernel/osrelease: failed to read file"),
+			expected: nil,
+		},
+		{
+			name: "version not parsable",
+			readFileFunc: func(_ string) ([]byte, error) {
+				return []byte("5-15-0"), nil
+			},
+			err:      errors.New("failed to parse kernel version: illegal version string \"5-15-0\""),
+			expected: nil,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			kernelVersion, err := getVersion(tc.readFileFunc)
+
+			if tc.err != nil {
+				assert.Equal(t, tc.err.Error(), err.Error())
+				assert.Nil(t, kernelVersion)
+			} else {
+				assert.NoError(t, err)
+				assert.Equal(t, tc.expected.Major(), kernelVersion.Major())
+				assert.Equal(t, tc.expected.Minor(), kernelVersion.Minor())
+				assert.Equal(t, tc.expected.Patch(), kernelVersion.Patch())
+			}
+		})
+	}
+}