Issue8 (#9)

`failed submits` mode implemented

README.md

@@ -20,7 +20,13 @@ docker build -t smscsim .
 docker run -p 2775:2775 -p 12775:12775 smscsim
 ```
 
-3) or use prebuild docker image (from hub.docker.com)
+3) or build and run with docker-compose
+
+```
+docker-compose up
+```
+
+4) or use prebuild docker image (from hub.docker.com)
 
 ```
 docker run -p 2775:2775 -p 12775:12775 ukarim/smscsim
@@ -55,4 +61,6 @@ delivered to the selected smpp session using a _deliver_sm_ PDU.
 
 * SMSC_PORT - override default smpp port
 * WEB_PORT - override default web port
-
+* FAILED_SUBMITS - if this is set to true, submit_sm requests will fail
+  - for submit_sm with even sequence number smscsim will return submit_sm_resp with command_status set to 0x00000008 (System Error)
+  - for submit_sm with odd sequence number smscsim will return DLR with UNDELIVERABLE message state

docker-compose.yaml

@@ -2,10 +2,11 @@ version: '3'
 
 services:
   smscsim:
-    image: ukarim/smscsim
+    build: .
     ports:
       - '2775:2775'
       - '12775:12775'
     environment:
       - TZ=Asia/Almaty
+#      - FAILED_SUBMITS=true
 

main.go

@@ -12,11 +12,12 @@ var wg sync.WaitGroup
 func main() {
 	smscPort := getPort("SMSC_PORT", 2775)
 	webPort := getPort("WEB_PORT", 12775)
+	failedSubmits := "true" == os.Getenv("FAILED_SUBMITS")
 
 	wg.Add(2)
 
 	// start smpp server
-	smsc := NewSmsc()
+	smsc := NewSmsc(failedSubmits)
 	go smsc.Start(smscPort, wg)
 
 	// start web server

smsc.go

@@ -37,6 +37,7 @@ const (
 	STS_INVALID_CMD   = 0x00000003
 	STS_INV_BIND_STS  = 0x00000004
 	STS_ALREADY_BOUND = 0x00000005
+	STS_SYS_ERROR     = 0x00000008
 )
 
 // data coding
@@ -66,12 +67,13 @@ type Tlv struct {
 }
 
 type Smsc struct {
-	Sessions map[int]Session
+	Sessions      map[int]Session
+	FailedSubmits bool
 }
 
-func NewSmsc() Smsc {
+func NewSmsc(failedSubmits bool) Smsc {
 	sessions := make(map[int]Session)
-	return Smsc{sessions}
+	return Smsc{sessions, failedSubmits}
 }
 
 func (smsc *Smsc) Start(port int, wg sync.WaitGroup) {
@@ -264,20 +266,25 @@ func handleSmppConnection(smsc *Smsc, conn net.Conn) {
 				// prepare submit_sm_resp
 				msgId := strconv.Itoa(rand.Int())
 
-				respBytes = stringBodyPDU(SUBMIT_SM_RESP, STS_OK, seqNum, msgId)
-
-				if registeredDlr != 0 {
-					go func() {
-						time.Sleep(2000 * time.Millisecond)
-						now := time.Now()
-						dlr := deliveryReceiptPDU(msgId, now, now)
-						if _, err := conn.Write(dlr); err != nil {
-							log.Printf("error sending delivery receipt to system_id[%s] due %v.", systemId, err)
-							return
-						} else {
-							log.Printf("delivery receipt for message [%s] was send to system_id[%s]", msgId, systemId)
-						}
-					}()
+				if smsc.FailedSubmits && seqNum%2 == 0 {
+					// return error response
+					respBytes = headerPDU(SUBMIT_SM_RESP, STS_SYS_ERROR, seqNum)
+				} else {
+					respBytes = stringBodyPDU(SUBMIT_SM_RESP, STS_OK, seqNum, msgId)
+					// send DLR if necessary
+					if registeredDlr != 0 {
+						go func() {
+							time.Sleep(2000 * time.Millisecond)
+							now := time.Now()
+							dlr := deliveryReceiptPDU(msgId, now, now, smsc.FailedSubmits)
+							if _, err := conn.Write(dlr); err != nil {
+								log.Printf("error sending delivery receipt to system_id[%s] due %v.", systemId, err)
+								return
+							} else {
+								log.Printf("delivery receipt for message [%s] was send to system_id[%s]", msgId, systemId)
+							}
+						}()
+					}
 				}
 			}
 		case DELIVER_SM_RESP: // deliver_sm_resp
@@ -334,12 +341,19 @@ func stringBodyPDU(cmdId, cmdSts, seqNum uint32, body string) []byte {
 	return buf
 }
 
-const DELIVERY_RECEIPT_FORMAT = "id:%s sub:001 dlvrd:001 submit date:%s done date:%s stat:DELIVRD err:000 Text:..."
+const DLR_RECEIPT_FORMAT = "id:%s sub:001 dlvrd:001 submit date:%s done date:%s stat:DELIVRD err:000 Text:..."
+const DLR_RECEIPT_FORMAT_FAILED = "id:%s sub:001 dlvrd:000 submit date:%s done date:%s stat:UNDELIV err:069 Text:..."
 
-func deliveryReceiptPDU(msgId string, submitDate, doneDate time.Time) []byte {
+func deliveryReceiptPDU(msgId string, submitDate, doneDate time.Time, failedDeliv bool) []byte {
 	sbtDateFrmt := submitDate.Format("0601021504")
 	doneDateFrmt := doneDate.Format("0601021504")
-	deliveryReceipt := fmt.Sprintf(DELIVERY_RECEIPT_FORMAT, msgId, sbtDateFrmt, doneDateFrmt)
+	dlrFmt := DLR_RECEIPT_FORMAT
+	msgState := []byte{2}
+	if failedDeliv {
+		dlrFmt = DLR_RECEIPT_FORMAT_FAILED
+		msgState = []byte{5}
+	}
+	deliveryReceipt := fmt.Sprintf(dlrFmt, msgId, sbtDateFrmt, doneDateFrmt)
 	var tlvs []Tlv
 
 	// receipted_msg_id TLV
@@ -350,7 +364,7 @@ func deliveryReceiptPDU(msgId string, submitDate, doneDate time.Time) []byte {
 	tlvs = append(tlvs, receiptMsgId)
 
 	// message_state TLV
-	msgStateTlv := Tlv{TLV_MESSAGE_STATE, 1, []byte{2}} // 2 - delivered
+	msgStateTlv := Tlv{TLV_MESSAGE_STATE, 1, msgState}
 	tlvs = append(tlvs, msgStateTlv)
 
 	return deliverSmPDU("", "", []byte(deliveryReceipt), CODING_DEFAULT, rand.Int(), tlvs)