feat(proxyproto): add proxy protocol support (#7738)

Signed-off-by: Adphi <philippe.adrien.nousse@gmail.com>

plugin/proxyproto/setup_test.go

@@ -0,0 +1,57 @@
+package proxyproto
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/coredns/caddy"
+	"github.com/coredns/coredns/core/dnsserver"
+)
+
+func TestSetup(t *testing.T) {
+	tests := []struct {
+		input              string
+		shouldErr          bool
+		expectedRoot       string // expected root, set to the controller. Empty for negative cases.
+		expectedErrContent string // substring from the expected error. Empty for positive cases.
+		config             bool
+	}{
+		// positive
+		{"proxyproto", false, "", "", true},
+		{"proxyproto {\nallow 127.0.0.1/8 ::1/128\n}", false, "", "", true},
+		{"proxyproto {\nallow 127.0.0.1/8 ::1/128\ndefault ignore\n}", false, "", "", true},
+		// Allow without any IPs is also valid
+		{"proxyproto {\nallow\n}", false, "", "", true},
+		// negative
+		{"proxyproto {\nunknown\n}", true, "", "unknown option", false},
+		{"proxyproto extra_arg", true, "", "Wrong argument", false},
+		{"proxyproto {\nallow invalid_ip\n}", true, "", "invalid CIDR address", false},
+		{"proxyproto {\nallow 127.0.0.1/8\ndefault invalid_policy\n}", true, "", "Wrong argument", false},
+	}
+	for i, test := range tests {
+		c := caddy.NewTestController("dns", test.input)
+		err := setup(c)
+		cfg := dnsserver.GetConfig(c)
+
+		if test.config && cfg.ProxyProtoConnPolicy == nil {
+			t.Errorf("Test %d: Expected ProxyProtoConnPolicy to be configured for input %s", i, test.input)
+		}
+		if !test.config && cfg.ProxyProtoConnPolicy != nil {
+			t.Errorf("Test %d: Expected ProxyProtoConnPolicy to NOT be configured for input %s", i, test.input)
+		}
+
+		if test.shouldErr && err == nil {
+			t.Errorf("Test %d: Expected error but found %s for input %s", i, err, test.input)
+		}
+
+		if err != nil {
+			if !test.shouldErr {
+				t.Errorf("Test %d: Expected no error but found one for input %s. Error was: %v", i, test.input, err)
+			}
+
+			if !strings.Contains(err.Error(), test.expectedErrContent) {
+				t.Errorf("Test %d: Expected error to contain: %v, found error: %v, input: %s", i, test.expectedErrContent, err, test.input)
+			}
+		}
+	}
+}