fix parsing of Rejoin request, and fix test

anthonykirby · Nov 8, 2023 · a5fd584 · a5fd584
1 parent 3fe2cc2
commit a5fd584
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Showing 2 changed files with 17 additions and 5 deletions.
diff --git a/__tests__/parse_test.ts b/__tests__/parse_test.ts
@@ -244,13 +244,13 @@ describe("parse example payload", () => {
   });
 
   it("should parse Rejoin Request packets", () => {
-    const message_hex = "C0008B658839";
+    const message_hex = "C000112233112233445566778811228B658839";
 
     const expectedPayload = {
-      PHYPayload: Buffer.from("C0008B658839", "hex"),
-      MACPayloadWithMIC: Buffer.from("008B658839", "hex"),
+      PHYPayload: Buffer.from("C000112233112233445566778811228B658839", "hex"),
+      MACPayloadWithMIC: Buffer.from("00112233112233445566778811228B658839", "hex"),
       MHDR: Buffer.from("C0", "hex"),
-      MACPayload: Buffer.from("00", "hex"),
+      MACPayload: Buffer.from("0011223311223344556677881122", "hex"),
       MIC: Buffer.from("8B658839", "hex"),
     };
 

diff --git a/src/lib/LoraPacket.ts b/src/lib/LoraPacket.ts
@@ -142,10 +142,16 @@ class LoraPacket {
     const mtype = this._getMType();
 
     if (mtype == MType.JOIN_REQUEST) {
+      if (incoming.length < 5 + 18) { 
+        throw new Error("contents too short for a Join Request");
+      }
       this.AppEUI = reverseBuffer(incoming.slice(1, 1 + 8));
       this.DevEUI = reverseBuffer(incoming.slice(9, 9 + 8));
       this.DevNonce = reverseBuffer(incoming.slice(17, 17 + 2));
     } else if (mtype == MType.JOIN_ACCEPT) {
+      if (incoming.length < 5 + 12) { 
+        throw new Error("contents too short for a Join Accept");
+      }
       this.AppNonce = reverseBuffer(incoming.slice(1, 1 + 3));
       this.NetID = reverseBuffer(incoming.slice(4, 4 + 3));
       this.DevAddr = reverseBuffer(incoming.slice(7, 7 + 4));
@@ -161,13 +167,19 @@ class LoraPacket {
     } else if (mtype == MType.REJOIN_REQUEST) {
       this.RejoinType = incoming.slice(1, 1 + 1);
       if (this.RejoinType[0] === 0 || this.RejoinType[0] === 2) {
+        if (incoming.length < 5 + 14) { 
+          throw new Error("contents too short for a Rejoin Request (Type 0/2)");
+        }
         this.NetID = reverseBuffer(incoming.slice(2, 2 + 3));
         this.DevEUI = reverseBuffer(incoming.slice(5, 5 + 8));
         this.RJCount0 = reverseBuffer(incoming.slice(13, 13 + 2));
       } else if (this.RejoinType[0] === 1) {
+        if (incoming.length < 5 + 19) { 
+          throw new Error("contents too short for a Rejoin Request (Type 1)");
+        }
         this.JoinEUI = reverseBuffer(incoming.slice(2, 2 + 8));
         this.DevEUI = reverseBuffer(incoming.slice(10, 10 + 8));
-        this.RJCount1 = reverseBuffer(incoming.slice(13, 13 + 2));
+        this.RJCount1 = reverseBuffer(incoming.slice(18, 18 + 2));
       }
     } else if (this.isDataMessage()) {
       this.FCtrl = this.MACPayload.slice(4, 5);