Make the length argument to print_unknown_data() unsigned.

All data lengths should be unsigned.

Author: guyharris

netdissect.h

@@ -662,7 +662,7 @@ extern u_int ppp_print(netdissect_options *, const u_char *, u_int);
 extern u_int pppoe_print(netdissect_options *, const u_char *, u_int);
 extern void pptp_print(netdissect_options *, const u_char *);
 extern void ptp_print(netdissect_options *, const u_char *, u_int);
-extern int print_unknown_data(netdissect_options *, const u_char *, const char *, int);
+extern int print_unknown_data(netdissect_options *, const u_char *, const char *, u_int);
 extern const char *q922_string(netdissect_options *, const u_char *, u_int);
 extern void q933_print(netdissect_options *, const u_char *, u_int);
 extern void radius_print(netdissect_options *, const u_char *, u_int);

util-print.c

@@ -473,17 +473,13 @@ void nd_print_invalid(netdissect_options *ndo)
  */
 
 int
-print_unknown_data(netdissect_options *ndo, const u_char *cp,const char *ident,int len)
+print_unknown_data(netdissect_options *ndo, const u_char *cp,
+                   const char *ident, u_int len)
 {
 	u_int len_to_print;
 
-	if (len < 0) {
-		ND_PRINT("%sDissector error: print_unknown_data called with negative length",
-		    ident);
-		return(0);
-	}
 	len_to_print = len;
-	if (ndo->ndo_snapend < cp) {
+	if (!ND_TTEST_LEN(cp, 0)) {
 		ND_PRINT("%sDissector error: print_unknown_data called with pointer past end of packet",
 		    ident);
 		return(0);