CALM FAST: Modernize packet parsing style.

Enable ND_LONGJMP_FROM_TCHECK, lose a few single-use variables and print
one field at a time. Print an undersized packet as invalid, not
truncated, and provide the reason.

diff --git a/print-calm-fast.c b/print-calm-fast.c
index ce040ce4dae5d31758af11101b94ad45434fa284..1220d867ec602a91c059f7d08cc553cd0d37ce70 100644 (file)
--- a/print-calm-fast.c
+++ b/print-calm-fast.c
@@ -23,6 +23,7 @@
 
 #include "netdissect-stdinc.h"
 
+#define ND_LONGJMP_FROM_TCHECK
 #include "netdissect.h"
 #include "extract.h"
 #include "addrtoname.h"
@@ -40,29 +41,31 @@
 void
 calm_fast_print(netdissect_options *ndo, const u_char *bp, u_int length, const struct lladdr_info *src)
 {
-       u_int srcNwref;
-       u_int dstNwref;
-
        ndo->ndo_protocol = "calm_fast";
-       ND_TCHECK_2(bp);
-       if (length < 2)
-               goto trunc;
-       srcNwref = GET_U_1(bp);
-       dstNwref = GET_U_1(bp + 1);
-       length -= 2;
-       bp += 2;
 
        ND_PRINT("CALM FAST");
        if (src != NULL)
                ND_PRINT(" src:%s", (src->addr_string)(ndo, src->addr));
        ND_PRINT("; ");
-       ND_PRINT("SrcNwref:%u; ", srcNwref);
-       ND_PRINT("DstNwref:%u; ", dstNwref);
+
+       if (length < 2) {
+               ND_PRINT(" (length %u < 2)", length);
+               goto invalid;
+       }
+
+       ND_PRINT("SrcNwref:%u; ", GET_U_1(bp));
+       length -= 1;
+       bp += 1;
+
+       ND_PRINT("DstNwref:%u; ", GET_U_1(bp));
+       length -= 1;
+       bp += 1;
 
        if (ndo->ndo_vflag)
                ND_DEFAULTPRINT(bp, length);
        return;
 
-trunc:
-       nd_print_trunc(ndo);
+invalid:
+       nd_print_invalid(ndo);
+       ND_TCHECK_LEN(bp, length);
 }