Add timeout, work on connection closing (previous commit left connections open)

mxrouter.go

@@ -23,6 +23,7 @@ import (
 	"os"
 	"strings"
 	"sync"
+	"time"
 
 	"github.com/go-ldap/ldap/v3"
 	"github.com/peterbourgon/ff"
@@ -30,7 +31,7 @@ import (
 )
 
 const (
-	version = "0.9.6"
+	version = "0.9.7.1"
 )
 
 var (
@@ -46,6 +47,7 @@ var (
 	ldapAttr    *string
 	defDomain   *string
 	pidFilePath *string
+	timeout     *int
 )
 
 func ldapSearch(searchReq *ldap.SearchRequest, attempt int) (*ldap.SearchResult, error) {
@@ -70,15 +72,41 @@ func ldapSearch(searchReq *ldap.SearchRequest, attempt int) (*ldap.SearchResult,
 	return result, err
 }
 
+func sendResponse(con net.Conn, respMsg string, respCode int) error {
+	response := fmt.Sprintf("%d %s\n", respCode, strings.Replace(respMsg, " ", "%20", -1))
+	_, err := con.Write([]byte(response))
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
 func handleConnection(connClt net.Conn, conLdap *ldap.Conn) {
 	var s string
 	var mxdom string
 	buf := make([]byte, 1024)
 
-	defer connClt.Close()
+	// Close connection when this function ends
+	defer func() {
+		logstream.Info("Closing connection")
+		connClt.Close()
+	}()
+
+	timeoutDuration := time.Duration(*timeout) * time.Second
+
+	for {
+		// Set a deadline for reading. Read operation will fail if no data
+		// is received after deadline.
+		connClt.SetReadDeadline(time.Now().Add(timeoutDuration))
+
 		readlen, err := connClt.Read(buf)
 		if err != nil {
-		fmt.Println("Error reading:", err.Error())
+			// Dont notice if client closed connection
+			if err.Error() != "EOF" {
+				logstream.Err(fmt.Sprintln("Error reading connection :", err.Error()))
+			}
+			return
 		}
 
 		// 1) Recupere le MX du domaine de l'adresse mail recue
@@ -88,20 +116,18 @@ func handleConnection(connClt net.Conn, conLdap *ldap.Conn) {
 			mxs, err := net.LookupMX(domain)
 			if err != nil {
 				logstream.Err(fmt.Sprintln("Error lookup mx: ", err))
-			s := strings.Replace(fmt.Sprintf("Error lookup MX: %s", err.Error()), " ", "%20", -1)
+				s := fmt.Sprintf("Error lookup MX: %s", err.Error())
-			response := fmt.Sprintf("500 %s\n", s)
+				sendResponse(connClt, s, 500)
-			connClt.Write([]byte(response))
+				continue
-			return
 			}
 			// 2) Requete LDAP pour voir si le domaine de second niveau du MX possede un routage particulier
 			// Protection contre ca : example.org.            72      IN      MX      0 .
 			// Considerons qu'il n'y aura jamais de "one letter TLD"
 			if len(mxs[0].Host) < 4 {
 				logstream.Err(fmt.Sprintln("No usable mx found"))
-			s := strings.Replace("No usable MX found", " ", "%20", -1)
+				s := "No usable MX found"
-			resp := fmt.Sprintf("500 %s\n", s)
+				sendResponse(connClt, s, 500)
-			connClt.Write([]byte(resp))
+				continue
-			return
 			}
 
 			mxslic := strings.Split(mxs[0].Host, ".")
@@ -119,29 +145,26 @@ func handleConnection(connClt net.Conn, conLdap *ldap.Conn) {
 			result, err := ldapSearch(searchReq, 0)
 			if err != nil {
 				logstream.Err(fmt.Sprintln("Error searching into LDAP: ", err))
-			s := strings.Replace(err.Error(), " ", "%20", -1)
+				s := err.Error()
-			response := fmt.Sprintf("500 %s\n", s)
+				sendResponse(connClt, s, 500)
-			connClt.Write([]byte(response))
+				continue
-			return
 			}
 
 			if len(result.Entries) != 1 {
 				if *debug {
 					logstream.Debug("Got no result, returning 500")
 				}
-			s := strings.Replace("No route defined", " ", "%20", -1)
+				s := "No route defined"
-			response := fmt.Sprintf("500 %s\n", s)
+				sendResponse(connClt, s, 500)
-			connClt.Write([]byte(response))
+				continue
-			return
 			}
 
 			// L'attribut n'existe pas
 			if len(result.Entries[0].Attributes) == 0 {
 				logstream.Err(fmt.Sprintf("Error searching into LDAP: Attribute %s not found for entry %s\n", *ldapAttr, result.Entries[0]))
-			s := strings.Replace(fmt.Sprintf("Attribute not found: %s", *ldapAttr), " ", "%20", -1)
+				s := fmt.Sprintf("Attribute not found: %s", *ldapAttr)
-			response := fmt.Sprintf("500 %s\n", s)
+				sendResponse(connClt, s, 500)
-			connClt.Write([]byte(response))
+				continue
-			return
 			}
 
 			if *debug {
@@ -149,19 +172,19 @@ func handleConnection(connClt net.Conn, conLdap *ldap.Conn) {
 			}
 			// Check if result is a FQDN, if not append defDomain
 			if strings.Contains(string(result.Entries[0].Attributes[0].Values[0]), ".") {
-			s = strings.Replace(fmt.Sprintf("FILTER relay:[%s]", result.Entries[0].Attributes[0].Values[0]), " ", "%20", -1)
+				s = fmt.Sprintf("FILTER relay:[%s]", result.Entries[0].Attributes[0].Values[0])
 			} else {
-			s = strings.Replace(fmt.Sprintf("FILTER relay:[%s]", fmt.Sprintf("%s.%s", result.Entries[0].Attributes[0].Values[0], *defDomain)), " ", "%20", -1)
+				s = fmt.Sprintf("FILTER relay:[%s]", fmt.Sprintf("%s.%s", result.Entries[0].Attributes[0].Values[0], *defDomain))
 			}
-		connClt.Write([]byte(fmt.Sprintf("200 %s\n", s)))
+			sendResponse(connClt, s, 200)
 		} else {
 			if *debug {
 				logstream.Debug("Incorrect input format : " + string(buf[:readlen-1]))
 			}
-		s := strings.Replace("Incorrect input format", " ", "%20", -1)
+			s := "Incorrect input format"
-		response := fmt.Sprintf("500 %s\n", s)
+			sendResponse(connClt, s, 500)
-		connClt.Write([]byte(response))
+			continue
-		return
+		}
 	}
 }
 
@@ -217,7 +240,8 @@ func main() {
 	ldapPass = fs.String("ldapPass", "", "LDAP user password (also via LDAPPASS env var)")
 	ldapAttr = fs.String("ldapAttr", "relayName", "LDAP attribute containing the relay name to return")
 	defDomain = fs.String("domain", "", "Domain to add to relay name if not a FQDN (also via DOMAIN env var)")
-	pidFilePath= fs.String("pidfile", "/var/run/mxrouter/mxrouter.pid", "PID File (also via PIDFILE env var)")
+	pidFilePath = fs.String("pidfile", "/var/run/mxrouter/mxrouter.pid", "PID File (also via PIDFILE env var)")
+	timeout = fs.Int("timeout", 5, "timeout in seconds")
 	_ = fs.String("config", "", "config file (optional)")
 
 	// Surcharge de la fonction Usage()