From: Denis Ovsienko <denis@ovsienko.info>
Date: Thu, 3 Dec 2020 22:03:29 +0000 (+0000)
Subject: LSP ping: Modernize packet parsing style.
X-Git-Tag: tcpdump-4.99-bp~44
X-Git-Url: https://git.tcpdump.org/tcpdump/commitdiff_plain/91b751b3f32bd44c7ebe9287dc4352ff82eb32aa

LSP ping: Modernize packet parsing style.

Enable ND_LONGJMP_FROM_TCHECK. Remove four redundant ND_TCHECK_LEN()
instances (there may be more). Fetch BFD discriminator value from the
right pointer.
---

diff --git a/print-lspping.c b/print-lspping.c
index ed74ad21..4c5fc4e8 100644
--- a/print-lspping.c
+++ b/print-lspping.c
@@ -23,6 +23,7 @@
 
 #include "netdissect-stdinc.h"
 
+#define ND_LONGJMP_FROM_TCHECK
 #include "netdissect.h"
 #include "extract.h"
 #include "addrtoname.h"
@@ -608,9 +609,6 @@ lspping_print(netdissect_options *ndo,
         if (tlen < sizeof(struct lspping_tlv_header))
             goto tooshort;
 
-        /* did we capture enough for fully decoding the tlv header ? */
-        ND_TCHECK_LEN(tptr, sizeof(struct lspping_tlv_header));
-
         lspping_tlv_header = (const struct lspping_tlv_header *)tptr;
         lspping_tlv_type=GET_BE_U_2(lspping_tlv_header->type);
         lspping_tlv_len=GET_BE_U_2(lspping_tlv_header->length);
@@ -648,8 +646,6 @@ lspping_print(netdissect_options *ndo,
                     tlv_hexdump = TRUE;
                     goto tlv_tooshort;
                 }
-                /* did we capture enough for fully decoding the subtlv header ? */
-                ND_TCHECK_LEN(tlv_tptr, sizeof(struct lspping_tlv_header));
                 subtlv_hexdump=FALSE;
 
                 lspping_subtlv_header = (const struct lspping_tlv_header *)tlv_tptr;
@@ -1026,8 +1022,7 @@ lspping_print(netdissect_options *ndo,
                 tlv_hexdump = TRUE;
                 goto tlv_tooshort;
             } else {
-                ND_TCHECK_LEN(tptr, LSPPING_TLV_BFD_DISCRIMINATOR_LEN);
-                ND_PRINT("\n\t    BFD Discriminator 0x%08x", GET_BE_U_4(tptr));
+                ND_PRINT("\n\t    BFD Discriminator 0x%08x", GET_BE_U_4(tlv_tptr));
             }
             break;
 
@@ -1040,7 +1035,6 @@ lspping_print(netdissect_options *ndo,
                 tlv_hexdump = TRUE;
                 goto tlv_tooshort;
             } else {
-                ND_TCHECK_LEN(tptr, LSPPING_TLV_VENDOR_ENTERPRISE_LEN);
                 vendor_id = GET_BE_U_4(tlv_tptr);
                 ND_PRINT("\n\t    Vendor: %s (0x%04x)",
                        tok2str(smi_values, "Unknown", vendor_id),
@@ -1083,7 +1077,4 @@ lspping_print(netdissect_options *ndo,
     return;
 tooshort:
     ND_PRINT("\n\t\t packet is too short");
-    return;
-trunc:
-    nd_print_trunc(ndo);
 }