Support a reporting via Syslog (#604)

* Support a reporting via syslog

* Update dependencies

config/config.go

@@ -18,7 +18,9 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 package config
 
 import (
+	"errors"
 	"fmt"
+	"log/syslog"
 	"os"
 	"runtime"
 	"strconv"
@@ -94,6 +96,7 @@ type Config struct {
 
 	EMail   SMTPConf
 	Slack   SlackConf
+	Syslog  SyslogConf
 	Default ServerInfo
 	Servers map[string]ServerInfo
 
@@ -260,6 +263,10 @@ func (c Config) ValidateOnReport() bool {
 		errs = append(errs, slackerrs...)
 	}
 
+	if syslogerrs := c.Syslog.Validate(); 0 < len(syslogerrs) {
+		errs = append(errs, syslogerrs...)
+	}
+
 	for _, err := range errs {
 		log.Error(err)
 	}
@@ -444,6 +451,124 @@ func (c *SlackConf) Validate() (errs []error) {
 	return
 }
 
+// SyslogConf is syslog config
+type SyslogConf struct {
+	Protocol string
+	Host     string `valid:"host"`
+	Port     string `valid:"port"`
+	Severity string
+	Facility string
+	Tag      string
+
+	Verbose bool
+}
+
+// Validate validates configuration
+func (c *SyslogConf) Validate() (errs []error) {
+	//  If protocol is empty, it will connect to the local syslog server.
+	if len(c.Protocol) > 0 && c.Protocol != "tcp" && c.Protocol != "udp" {
+		errs = append(errs, errors.New(`protocol must be "tcp" or "udp"`))
+	}
+
+	// Default port: 514
+	if c.Port == "" {
+		c.Port = "514"
+	}
+
+	if _, err := c.GetSeverity(); err != nil {
+		errs = append(errs, err)
+	}
+
+	if _, err := c.GetFacility(); err != nil {
+		errs = append(errs, err)
+	}
+
+	if _, err := valid.ValidateStruct(c); err != nil {
+		errs = append(errs, err)
+	}
+	return errs
+}
+
+// GetSeverity gets severity
+func (c *SyslogConf) GetSeverity() (syslog.Priority, error) {
+	if c.Severity == "" {
+		return syslog.LOG_INFO, nil
+	}
+
+	switch c.Severity {
+	case "emerg":
+		return syslog.LOG_EMERG, nil
+	case "alert":
+		return syslog.LOG_ALERT, nil
+	case "crit":
+		return syslog.LOG_CRIT, nil
+	case "err":
+		return syslog.LOG_ERR, nil
+	case "warning":
+		return syslog.LOG_WARNING, nil
+	case "notice":
+		return syslog.LOG_NOTICE, nil
+	case "info":
+		return syslog.LOG_INFO, nil
+	case "debug":
+		return syslog.LOG_DEBUG, nil
+	default:
+		return -1, fmt.Errorf("Invalid severity: %s", c.Severity)
+	}
+}
+
+// GetFacility gets facility
+func (c *SyslogConf) GetFacility() (syslog.Priority, error) {
+	if c.Facility == "" {
+		return syslog.LOG_AUTH, nil
+	}
+
+	switch c.Facility {
+	case "kern":
+		return syslog.LOG_KERN, nil
+	case "user":
+		return syslog.LOG_USER, nil
+	case "mail":
+		return syslog.LOG_MAIL, nil
+	case "daemon":
+		return syslog.LOG_DAEMON, nil
+	case "auth":
+		return syslog.LOG_AUTH, nil
+	case "syslog":
+		return syslog.LOG_SYSLOG, nil
+	case "lpr":
+		return syslog.LOG_LPR, nil
+	case "news":
+		return syslog.LOG_NEWS, nil
+	case "uucp":
+		return syslog.LOG_UUCP, nil
+	case "cron":
+		return syslog.LOG_CRON, nil
+	case "authpriv":
+		return syslog.LOG_AUTHPRIV, nil
+	case "ftp":
+		return syslog.LOG_FTP, nil
+	case "local0":
+		return syslog.LOG_LOCAL0, nil
+	case "local1":
+		return syslog.LOG_LOCAL1, nil
+	case "local2":
+		return syslog.LOG_LOCAL2, nil
+	case "local3":
+		return syslog.LOG_LOCAL3, nil
+	case "local4":
+		return syslog.LOG_LOCAL4, nil
+	case "local5":
+		return syslog.LOG_LOCAL5, nil
+	case "local6":
+		return syslog.LOG_LOCAL6, nil
+	case "local7":
+		return syslog.LOG_LOCAL7, nil
+	default:
+		return -1, fmt.Errorf("Invalid facility: %s", c.Facility)
+	}
+}
+
 // ServerInfo has SSH Info, additional CPE packages to scan.
 type ServerInfo struct {
 	ServerName  string