Add SSL certificate checker

Implement SSL certificate checking functionality

server/service-operation/operations/ssl_operation.go

@@ -0,0 +1,159 @@
+
+package operations
+
+import (
+	"crypto/tls"
+	"fmt"
+	"net"
+	"strings"
+	"time"
+
+	"service-operation/types"
+)
+
+type SSLOperation struct {
+	timeout time.Duration
+}
+
+func NewSSLOperation(timeout time.Duration) *SSLOperation {
+	return &SSLOperation{
+		timeout: timeout,
+	}
+}
+
+func (op *SSLOperation) Execute(domain string) (*types.OperationResult, error) {
+	startTime := time.Now()
+	
+	// Clean and normalize domain
+	domain = op.normalizeDomain(domain)
+	
+	// Validate domain format
+	if domain == "" {
+		return op.createErrorResult(domain, startTime, "domain cannot be empty")
+	}
+	
+	// Add port if not present
+	host := domain
+	if !strings.Contains(host, ":") {
+		host = host + ":443"
+	}
+
+	// Set up TLS connection with timeout
+	dialer := &net.Dialer{
+		Timeout: op.timeout,
+	}
+	
+	// Create TLS config with proper verification
+	tlsConfig := &tls.Config{
+		ServerName:         strings.Split(host, ":")[0],
+		InsecureSkipVerify: false,
+		MinVersion:         tls.VersionTLS12,
+	}
+	
+	// Attempt TLS connection
+	conn, err := tls.DialWithDialer(dialer, "tcp", host, tlsConfig)
+	
+	endTime := time.Now()
+	responseTime := endTime.Sub(startTime)
+	
+	if err != nil {
+		return &types.OperationResult{
+			Type:         types.OperationSSL,
+			Host:         strings.Split(host, ":")[0],
+			Success:      false,
+			ResponseTime: responseTime,
+			Error:        fmt.Sprintf("TLS connection failed: %v", err),
+			StartTime:    startTime,
+			EndTime:      endTime,
+		}, nil
+	}
+	defer conn.Close()
+
+	// Get certificate chain information
+	state := conn.ConnectionState()
+	if len(state.PeerCertificates) == 0 {
+		return &types.OperationResult{
+			Type:         types.OperationSSL,
+			Host:         strings.Split(host, ":")[0],
+			Success:      false,
+			ResponseTime: responseTime,
+			Error:        "No certificates found in chain",
+			StartTime:    startTime,
+			EndTime:      endTime,
+		}, nil
+	}
+
+	cert := state.PeerCertificates[0]
+	hostname := strings.Split(host, ":")[0]
+	
+	// Perform comprehensive certificate validation
+	validationError := op.validateCertificate(cert, hostname)
+	
+	// Calculate days left until expiration
+	daysLeft := int(time.Until(cert.NotAfter).Hours() / 24)
+	
+	// Extract Subject Alternative Names
+	sans := op.extractSANs(cert)
+	
+	// Get resolved IP address
+	resolvedIP := op.getResolvedIP(hostname)
+	
+	// Extract certificate algorithm information
+	algorithm := op.getCertificateAlgorithm(cert)
+	
+	// Extract issuer organization (O=) instead of full distinguished name
+	issuerOrganization := op.extractIssuerOrganization(cert.Issuer)
+	
+	// Extract subject organization (O=) instead of full distinguished name
+	subjectOrganization := op.extractSubjectOrganization(cert.Subject)
+	
+	// Check if certificate is valid (not expired and passes validation)
+	isValid := validationError == nil && time.Now().Before(cert.NotAfter) && time.Now().After(cert.NotBefore)
+	
+	// Build detailed error message if validation failed
+	errorMsg := ""
+	if validationError != nil {
+		errorMsg = validationError.Error()
+	} else if time.Now().After(cert.NotAfter) {
+		errorMsg = "Certificate has expired"
+	} else if time.Now().Before(cert.NotBefore) {
+		errorMsg = "Certificate is not yet valid"
+	}
+
+	// Create comprehensive result
+	result := &types.OperationResult{
+		Type:         types.OperationSSL,
+		Host:         hostname,
+		Success:      isValid,
+		ResponseTime: responseTime,
+		Error:        errorMsg,
+		StartTime:    startTime,
+		EndTime:      endTime,
+		
+		// SSL specific fields - using organization instead of full DN
+		SSLValidFrom:     cert.NotBefore,
+		SSLValidTill:     cert.NotAfter,
+		SSLDaysLeft:      daysLeft,
+		SSLIssuer:        issuerOrganization,        // Now shows "Google Trust Services" instead of full DN
+		SSLSubject:       subjectOrganization,       // Now shows organization instead of full DN
+		SSLSerialNumber:  cert.SerialNumber.String(),
+		SSLAlgorithm:     algorithm,
+		SSLSANs:          strings.Join(sans, ","),
+		SSLResolvedIP:    resolvedIP,
+	}
+
+	return result, nil
+}
+
+// createErrorResult creates a standardized error result
+func (op *SSLOperation) createErrorResult(domain string, startTime time.Time, errorMsg string) (*types.OperationResult, error) {
+	return &types.OperationResult{
+		Type:         types.OperationSSL,
+		Host:         domain,
+		Success:      false,
+		ResponseTime: time.Since(startTime),
+		Error:        errorMsg,
+		StartTime:    startTime,
+		EndTime:      time.Now(),
+	}, nil
+}