new syslog server with tcp and tls support, added tests

.travis.yml

@@ -0,0 +1,5 @@
+language: go
+go_import_path: github.com/Neo23x0/simplesyslog
+notifications:
+  email: false
+  slack: nextron-systems:Q1f2uRSIFH0Sf5IzT884z4YR

server.go

@@ -0,0 +1,111 @@
+// Simple Syslog Server that
+// supports UDP, TCP and TLS.
+//
+// Marcel Gebhardt
+// April 2018
+
+package simplesyslog
+
+import (
+	"crypto/tls"
+	"fmt"
+	"log/syslog"
+	"net"
+	"os"
+	"time"
+)
+
+// ConnectionType defines wheather to connect via UDP or TCP (or TLS)
+type ConnectionType string
+
+const (
+	// ConnectionUDP connects via UDP
+	ConnectionUDP ConnectionType = "udp"
+	// ConnectionTCP connects via TCP
+	ConnectionTCP ConnectionType = "tcp"
+	// ConnectionTLS connects via TLS
+	ConnectionTLS ConnectionType = "tls"
+)
+
+const (
+	// DefaultHostname will be used if hostname could not be determined
+	DefaultHostname string = "unknown"
+	// DefaultIP will be used if ip could not be determined
+	DefaultIP string = ""
+)
+
+// Server holds a connection to a specified address
+type Server struct {
+	Hostname string   // Hostname of the system
+	IP       string   // IP of the system
+	Rfc3164  bool     // rfc standard for length reduction
+	Rfc5424  bool     // rfc standard for length reduction
+	conn     net.Conn // connection to the syslog server
+}
+
+// NewServer initializes a new server connection.
+// Examples:
+//   - NewServer(ConnectionUDP, "172.0.0.1:514")
+//   - NewServer(ConnectionTCP, ":514")
+//   - NewServer(ConnectionTLS, "172.0.0.1:514")
+func NewServer(connectionType ConnectionType, address string) (*Server, error) {
+	// Validate data
+	if connectionType != ConnectionUDP && connectionType != ConnectionTCP && connectionType != ConnectionTLS {
+		return nil, fmt.Errorf("unknown connection type '%s'", connectionType)
+	}
+	var (
+		conn net.Conn
+		err  error
+	)
+	// connect via udp / tcp / tls
+	if connectionType == ConnectionTLS {
+		conn, err = tls.Dial(string(ConnectionTCP), address, &tls.Config{
+			InsecureSkipVerify: true,
+		})
+	} else {
+		conn, err = net.Dial(string(connectionType), address)
+	}
+	if err != nil {
+		return nil, err
+	}
+	// get hostname and ip of system
+	hostname, err := os.Hostname()
+	if err != nil {
+		hostname = DefaultHostname
+	}
+	ip, _, err := net.SplitHostPort(conn.LocalAddr().String())
+	if err != nil {
+		ip = DefaultIP
+	}
+	// return the server
+	return &Server{
+		Hostname: hostname,
+		IP:       ip,
+		conn:     conn,
+	}, nil
+}
+
+// Send sends a syslog message with a specified priority.
+// Examples:
+//   - Send("foo", syslog.LOG_LOCAL0|syslog.LOG_NOTICE)
+//   - Send("bar", syslog.LOG_DAEMON|syslog.LOG_DEBUG)
+func (server *Server) Send(message string, priority syslog.Priority) error {
+	timestamp := time.Now().Format("Jan _2 15:04:05")
+	hostnameCombi := fmt.Sprintf("%s/%s", server.Hostname, server.IP)
+	header := fmt.Sprintf("<%d>%s %s", int(priority), timestamp, hostnameCombi)
+	// RFC length reduction
+	if server.Rfc3164 && len(message) > 1024 {
+		message = fmt.Sprintf("%s...", message[:1020])
+	}
+	if server.Rfc5424 && len(message) > 2048 {
+		message = fmt.Sprintf("%s...", message[:2044])
+	}
+	// Send message
+	_, err := fmt.Fprintf(server.conn, "%s %s", header, message)
+	return err
+}
+
+// Close closes the server connection gracefully.
+func (server *Server) Close() error {
+	return server.conn.Close()
+}

server_test.go

@@ -0,0 +1,173 @@
+package simplesyslog
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"encoding/pem"
+	"io/ioutil"
+	"log/syslog"
+	"net"
+	"regexp"
+	"strconv"
+	"testing"
+	"time"
+)
+
+const host = "127.0.0.1:15140"
+
+const tlsCRT = `-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`
+
+const tlsKEY = `-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----`
+
+var tlsConfig *tls.Config
+
+var messageRegex = regexp.MustCompile(`<133>[A-Z][a-z]{2} (([0-9]{2})|( [0-9])) [0-9]{2}:[0-9]{2}:[0-9]{2} testing\/127\.0\.0\.1 foo bar baz`)
+
+func TestNewServer(t *testing.T) {
+	testNewServerTCP(t, false)
+	testNewServerTCP(t, true)
+	testNewServerUDP(t)
+}
+
+func testNewServerUDP(t *testing.T) {
+	t.Logf("testing udp")
+	serverAddr, err := net.ResolveUDPAddr("udp", host)
+	if err != nil {
+		t.Fatalf("could not resolve udp addr: %s", err)
+	}
+	conn, err := net.ListenUDP("udp", serverAddr)
+	if err != nil {
+		t.Fatalf("could not listen udp: %s", err)
+	}
+	if err := conn.SetReadDeadline(time.Now().Add(time.Second * 5)); err != nil {
+		t.Fatalf("could not set read deadline: %s", err)
+	}
+	defer conn.Close()
+	go func() {
+		/*
+		 * Send the message 'foo bar baz' to the syslog server
+		 */
+		server, err := NewServer(ConnectionUDP, host)
+		if err != nil {
+			t.Fatalf("could not initialize server: %s", err)
+		}
+		server.Hostname = "testing" // overwrite hostname for testing
+		defer server.Close()
+		if err := server.Send("foo bar baz", syslog.LOG_LOCAL0|syslog.LOG_NOTICE); err != nil {
+			t.Fatalf("could not send message: %s", err)
+		}
+	}()
+	buf := make([]byte, 1024)
+	n, _, err := conn.ReadFrom(buf)
+	if err != nil {
+		t.Fatalf("could not read udp: %s", err)
+	}
+	b := buf[:n]
+	if !messageRegex.MatchString(string(b)) {
+		t.Fatalf("wrong message: %s", string(b))
+	} else {
+		t.Logf("correct message: '%s'", string(b))
+	}
+}
+
+func testNewServerTCP(t *testing.T, useTLS bool) {
+	t.Logf("testing tcp with tls '%s'", strconv.FormatBool(useTLS))
+	var (
+		listener net.Listener
+		err      error
+	)
+	if useTLS {
+		listener, err = tls.Listen("tcp", host, tlsConfig)
+	} else {
+		listener, err = net.Listen("tcp", host)
+	}
+	if err != nil {
+		t.Fatalf("could not listen: %s", err)
+	}
+	defer listener.Close()
+	go func() {
+		/*
+		 * Send the message 'foo bar baz' to the syslog server
+		 */
+		connectionType := ConnectionTCP
+		if useTLS {
+			connectionType = ConnectionTLS
+		}
+		server, err := NewServer(connectionType, host)
+		if err != nil {
+			t.Fatalf("could not initialize server: %s", err)
+		}
+		server.Hostname = "testing" // overwrite hostname for testing
+		defer server.Close()
+		if err := server.Send("foo bar baz", syslog.LOG_LOCAL0|syslog.LOG_NOTICE); err != nil {
+			t.Fatalf("could not send message: %s", err)
+		}
+	}()
+	for {
+		conn, err := listener.Accept()
+		if err != nil {
+			t.Fatalf("could not accept connection: %s", err)
+		}
+		defer conn.Close()
+		b, err := ioutil.ReadAll(conn)
+		if err != nil {
+			t.Fatalf("could not read all: %s", err)
+		}
+		if !messageRegex.MatchString(string(b)) {
+			t.Fatalf("wrong message: %s", string(b))
+		} else {
+			t.Logf("correct message: '%s'", string(b))
+		}
+		return
+	}
+}
+
+func init() {
+	pemCert, _ := pem.Decode([]byte(tlsCRT))
+	if pemCert == nil {
+		panic("no test tls certificate")
+	}
+	pemKey, _ := pem.Decode([]byte(tlsKEY))
+	if pemKey == nil {
+		panic("no test tls key")
+	}
+	privateKey, err := x509.ParsePKCS1PrivateKey(pemKey.Bytes)
+	if err != nil {
+		panic("invalid test tls key")
+	}
+	cert := &tls.Certificate{
+		Certificate: [][]byte{pemCert.Bytes},
+		PrivateKey:  privateKey,
+	}
+	tlsConfig = &tls.Config{
+		Certificates: []tls.Certificate{*cert},
+		MinVersion:   tls.VersionTLS11,
+	}
+}