Add Wireguard-based K8s pod networking

This adds a pod networking runnable based on Wireguard which watches all nodes
and adds their K8s IPAM allocations as routes into the kernel & WireGuard. It only depends
on K8s and only performs direct routing.

Test Plan: Manually tested by spinning up a two-node cluster and running two Alpine pods pinging eachother. Can be covered by E2E tests once we can do image preseeding for the test infra (T793).

Bug: T487

X-Origin-Diff: phab/D573
GitOrigin-RevId: ba3fc36f421fd75002f6cf8bea25ed6f1eb457b0
diff --git a/core/pkg/jsonpatch/jsonpatch_test.go b/core/pkg/jsonpatch/jsonpatch_test.go
new file mode 100644
index 0000000..33a56ba
--- /dev/null
+++ b/core/pkg/jsonpatch/jsonpatch_test.go
@@ -0,0 +1,66 @@
+// Copyright 2020 The Monogon Project Authors.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// 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 jsonpatch
+
+import (
+	"testing"
+)
+
+func TestEncodeJSONRefToken(t *testing.T) {
+	tests := []struct {
+		name  string
+		token string
+		want  string
+	}{
+		{"Passes through normal characters", "asdf123", "asdf123"},
+		{"Encodes simple slashes", "a/b", "a~1b"},
+		{"Encodes tildes", "m~n", "m~0n"},
+		{"Encodes bot tildes and slashes", "a/m~n", "a~1m~0n"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := EncodeJSONRefToken(tt.token); got != tt.want {
+				t.Errorf("EncodeJSONRefToken() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestPointerFromParts(t *testing.T) {
+	type args struct {
+		pathParts []string
+	}
+	tests := []struct {
+		name string
+		args args
+		want string
+	}{
+		{"Empty path", args{[]string{}}, ""},
+		{"Single level path", args{[]string{"foo"}}, "/foo"},
+		{"Multi-level path", args{[]string{"foo", "0"}}, "/foo/0"},
+		{"Path starting with empty key", args{[]string{""}}, "/"},
+		{"Path with part containing /", args{[]string{"a/b"}}, "/a~1b"},
+		{"Path with part containing spaces", args{[]string{" "}}, "/ "},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := PointerFromParts(tt.args.pathParts); got != tt.want {
+				t.Errorf("PointerFromParts() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}