first version, unittest not fin

pkg/common/common.go

@@ -1,13 +1,15 @@
 package common
 
 import (
+	"fmt"
 	"net"
 	"ssh-proxy/pkg/logger"
 	"strconv"
 	"time"
+	"unicode/utf8"
 )
 
-func CheckRemoteSSH(host string, port int, timeout int) bool {
+func CheckRemoteTCP(host string, port int, timeout int) error {
 	log := logger.ColorLogger{}
 	connTimeout := time.Duration(timeout) * time.Second
 	if connTimeout <= 0 {
@@ -17,8 +19,62 @@ func CheckRemoteSSH(host string, port int, timeout int) bool {
 	conn, err := net.DialTimeout("tcp", net.JoinHostPort(host, strconv.Itoa(port)), connTimeout)
 	if err != nil {
 		log.Trace("Check Remote Host SSH Fail: Host(%s:%d) %s", host, port, err)
-		return false
+		return err
 	}
 	defer conn.Close()
-	return true
+	return nil
+}
+
+// checkDomain returns an error if the domain name is not valid
+// See https://tools.ietf.org/html/rfc1034#section-3.5 and
+// https://tools.ietf.org/html/rfc1123#section-2.
+func CheckDomain(name string) error {
+	switch {
+	case len(name) == 0:
+		return nil // an empty domain name will result in a cookie without a domain restriction
+	case len(name) > 255:
+		return fmt.Errorf("cookie domain: name length is %d, can't exceed 255", len(name))
+	}
+	var l int
+	for i := 0; i < len(name); i++ {
+		b := name[i]
+		if b == '.' {
+			// check domain labels validity
+			switch {
+			case i == l:
+				return fmt.Errorf("cookie domain: invalid character '%c' at offset %d: label can't begin with a period", b, i)
+			case i-l > 63:
+				return fmt.Errorf("cookie domain: byte length of label '%s' is %d, can't exceed 63", name[l:i], i-l)
+			case name[l] == '-':
+				return fmt.Errorf("cookie domain: label '%s' at offset %d begins with a hyphen", name[l:i], l)
+			case name[i-1] == '-':
+				return fmt.Errorf("cookie domain: label '%s' at offset %d ends with a hyphen", name[l:i], l)
+			}
+			l = i + 1
+			continue
+		}
+		// test label character validity, note: tests are ordered by decreasing validity frequency
+		if !(b >= 'a' && b <= 'z' || b >= '0' && b <= '9' || b == '-' || b >= 'A' && b <= 'Z') {
+			// show the printable unicode character starting at byte offset i
+			c, _ := utf8.DecodeRuneInString(name[i:])
+			if c == utf8.RuneError {
+				return fmt.Errorf("cookie domain: invalid rune at offset %d", i)
+			}
+			return fmt.Errorf("cookie domain: invalid character '%c' at offset %d", c, i)
+		}
+	}
+	// check top level domain validity
+	switch {
+	case l == len(name):
+		return fmt.Errorf("cookie domain: missing top level domain, domain can't end with a period")
+	case len(name)-l > 63:
+		return fmt.Errorf("cookie domain: byte length of top level domain '%s' is %d, can't exceed 63", name[l:], len(name)-l)
+	case name[l] == '-':
+		return fmt.Errorf("cookie domain: top level domain '%s' at offset %d begins with a hyphen", name[l:], l)
+	case name[len(name)-1] == '-':
+		return fmt.Errorf("cookie domain: top level domain '%s' at offset %d ends with a hyphen", name[l:], l)
+	case name[l] >= '0' && name[l] <= '9':
+		return fmt.Errorf("cookie domain: top level domain '%s' at offset %d begins with a digit", name[l:], l)
+	}
+	return nil
 }

pkg/common/common_test.go

@@ -11,7 +11,7 @@ func TestCheckRemoteSSH(t *testing.T) {
 	tests := []struct {
 		name string
 		args args
-		want bool
+		want error
 	}{
 		{
 			name: "test check localhost ssh port",
@@ -20,12 +20,12 @@ func TestCheckRemoteSSH(t *testing.T) {
 				port:    22,
 				timeout: 5,
 			},
-			want: true,
+			want: nil,
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			if got := CheckRemoteSSH(tt.args.host, tt.args.port, tt.args.timeout); got != tt.want {
+			if got := CheckRemoteTCP(tt.args.host, tt.args.port, tt.args.timeout); got != tt.want {
 				t.Errorf("CheckRemoteSSH() = %v, want %v", got, tt.want)
 			}
 		})