X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/ba8936b39b0ce2ff02f3aeb307df4c27657652d8..a8abce5c5e2dce2ba6dbccd5d3829da104b80f9c:/print-isoclns.c

diff --git a/print-isoclns.c b/print-isoclns.c
index 38f40d19..b9935ebd 100644
--- a/print-isoclns.c
+++ b/print-isoclns.c
@@ -29,7 +29,7 @@
 /*
  * specification:
  *
- * CLNP: ISO 8473
+ * CLNP: ISO 8473 (respective ITU version is at http://www.itu.int/rec/T-REC-X.233/en/)
  * ES-IS: ISO 9542
  * IS-IS: ISO 10589
  */
@@ -679,10 +679,7 @@ void
 isoclns_print(netdissect_options *ndo, const u_char *p, u_int length)
 {
 	ndo->ndo_protocol = "isoclns";
-	if (!ND_TTEST_1(p)) { /* enough bytes on the wire ? */
-		ND_PRINT("|OSI");
-		return;
-	}
+	ND_TCHECK_1(p); /* enough bytes on the wire ? */
 
 	if (ndo->ndo_eflag)
 		ND_PRINT("OSI NLPID %s (0x%02x): ", tok2str(nlpid_values, "Unknown", EXTRACT_U_1(p)), EXTRACT_U_1(p));
@@ -731,6 +728,9 @@ isoclns_print(netdissect_options *ndo, const u_char *p, u_int length)
 			print_unknown_data(ndo, p, "\n\t", length);
 		break;
 	}
+	return;
+trunc:
+	nd_print_trunc(ndo);
 }
 
 #define	CLNP_PDU_ER	 1
@@ -903,7 +903,7 @@ clnp_print(netdissect_options *ndo,
         }
 
         /* now walk the options */
-        while (li_remaining >= 2) {
+        while (li_remaining != 0) {
             u_int op, opli;
             const uint8_t *tptr;
 
@@ -1058,6 +1058,18 @@ clnp_print(netdissect_options *ndo,
                 break;
             }
 
+        /* The cases above break from the switch block if they see and print
+         * a CLNP header in the Data part. For an Error Report PDU this is
+         * described in Section 7.9.6 of ITU X.233 (1997 E), also known as
+         * ISO/IEC 8473-1:1998(E). It is not clear why in this code the same
+         * applies to an Echo Response PDU, as the standard does not specify
+         * the contents -- could be a proprietary extension or a bug. In either
+         * case, if the Data part does not contain a CLNP header, its structure
+         * is considered unknown and the decoding falls through to print the
+         * contents as-is.
+         */
+        ND_FALL_THROUGH;
+
         case 	CLNP_PDU_DT:
         case 	CLNP_PDU_MD:
         case 	CLNP_PDU_ERQ:
@@ -1386,6 +1398,8 @@ esis_print(netdissect_options *ndo,
                 print_unknown_data(ndo, pptr, "\n\t  ", opli);
             pptr += opli;
         }
+        return;
+
 trunc:
 	nd_print_trunc(ndo);
 }
@@ -1408,6 +1422,7 @@ isis_print_mcid(netdissect_options *ndo,
 
   for(i=0;i<16;i++)
     ND_PRINT("%.2x ", mcid->digest[i]);
+  return;
 
 trunc:
   nd_print_trunc(ndo);