dns: add tests for TXT response parsing

Add valid and invalid examples.

src/app-layer-dns-udp.c

@@ -527,9 +527,86 @@ end:
     return (result);
 }
 
+/** \test TXT records in answer */
+static int DNSUDPParserTest04 (void) {
+    int result = 0;
+    uint8_t buf[] = {
+        0xc2,0x2f,0x81,0x80,0x00,0x01,0x00,0x01,0x00,0x01,0x00,0x01,0x0a,0x41,0x41,0x41,
+        0x41,0x41,0x4f,0x31,0x6b,0x51,0x41,0x05,0x3d,0x61,0x75,0x74,0x68,0x03,0x73,0x72,
+        0x76,0x06,0x74,0x75,0x6e,0x6e,0x65,0x6c,0x03,0x63,0x6f,0x6d,0x00,0x00,0x10,0x00,
+        0x01,
+        /* answer record start */
+        0xc0,0x0c,0x00,0x10,0x00,0x01,0x00,0x00,0x00,0x03,0x00,0x22,
+        /* txt record starts: */
+        0x20, /* <txt len 32 */  0x41,0x68,0x76,0x4d,0x41,0x41,0x4f,0x31,0x6b,0x41,0x46,
+        0x45,0x35,0x54,0x45,0x39,0x51,0x54,0x6a,0x46,0x46,0x4e,0x30,0x39,0x52,0x4e,0x31,
+        0x6c,0x59,0x53,0x44,0x6b,0x00, /* <txt len 0 */   0xc0,0x1d,0x00,0x02,0x00,0x01,
+        0x00,0x09,0x3a,0x80,0x00,0x09,0x06,0x69,0x6f,0x64,0x69,0x6e,0x65,0xc0,0x21,0xc0,
+        0x6b,0x00,0x01,0x00,0x01,0x00,0x09,0x3a,0x80,0x00,0x04,0x0a,0x1e,0x1c,0x5f
+    };
+    size_t buflen = sizeof(buf);
+    Flow *f = NULL;
+
+    f = UTHBuildFlow(AF_INET, "1.2.3.4", "1.2.3.5", 1024, 53);
+    if (f == NULL)
+        goto end;
+    f->proto = IPPROTO_UDP;
+    f->alproto = ALPROTO_DNS;
+    f->alstate = DNSStateAlloc();
+
+    int r = DNSUDPResponseParse(f, f->alstate, NULL, buf, buflen, NULL);
+    if (r != 1)
+        goto end;
+
+    result = 1;
+end:
+    UTHFreeFlow(f);
+    return (result);
+}
+
+/** \test TXT records in answer, bad txtlen */
+static int DNSUDPParserTest05 (void) {
+    int result = 0;
+    uint8_t buf[] = {
+        0xc2,0x2f,0x81,0x80,0x00,0x01,0x00,0x01,0x00,0x01,0x00,0x01,0x0a,0x41,0x41,0x41,
+        0x41,0x41,0x4f,0x31,0x6b,0x51,0x41,0x05,0x3d,0x61,0x75,0x74,0x68,0x03,0x73,0x72,
+        0x76,0x06,0x74,0x75,0x6e,0x6e,0x65,0x6c,0x03,0x63,0x6f,0x6d,0x00,0x00,0x10,0x00,
+        0x01,
+        /* answer record start */
+        0xc0,0x0c,0x00,0x10,0x00,0x01,0x00,0x00,0x00,0x03,0x00,0x22,
+        /* txt record starts: */
+        0x40, /* <txt len 64 */  0x41,0x68,0x76,0x4d,0x41,0x41,0x4f,0x31,0x6b,0x41,0x46,
+        0x45,0x35,0x54,0x45,0x39,0x51,0x54,0x6a,0x46,0x46,0x4e,0x30,0x39,0x52,0x4e,0x31,
+        0x6c,0x59,0x53,0x44,0x6b,0x00, /* <txt len 0 */   0xc0,0x1d,0x00,0x02,0x00,0x01,
+        0x00,0x09,0x3a,0x80,0x00,0x09,0x06,0x69,0x6f,0x64,0x69,0x6e,0x65,0xc0,0x21,0xc0,
+        0x6b,0x00,0x01,0x00,0x01,0x00,0x09,0x3a,0x80,0x00,0x04,0x0a,0x1e,0x1c,0x5f
+    };
+    size_t buflen = sizeof(buf);
+    Flow *f = NULL;
+
+    f = UTHBuildFlow(AF_INET, "1.2.3.4", "1.2.3.5", 1024, 53);
+    if (f == NULL)
+        goto end;
+    f->proto = IPPROTO_UDP;
+    f->alproto = ALPROTO_DNS;
+    f->alstate = DNSStateAlloc();
+
+    int r = DNSUDPResponseParse(f, f->alstate, NULL, buf, buflen, NULL);
+    if (r != -1)
+        goto end;
+
+    result = 1;
+end:
+    UTHFreeFlow(f);
+    return (result);
+}
+
+
 void DNSUDPParserRegisterTests(void) {
 	UtRegisterTest("DNSUDPParserTest01", DNSUDPParserTest01, 1);
 	UtRegisterTest("DNSUDPParserTest02", DNSUDPParserTest02, 1);
 	UtRegisterTest("DNSUDPParserTest03", DNSUDPParserTest03, 1);
+	UtRegisterTest("DNSUDPParserTest04", DNSUDPParserTest04, 1);
+	UtRegisterTest("DNSUDPParserTest05", DNSUDPParserTest05, 1);
 }
 #endif