Added checks for printing variables with wrong types.

When -OQ command line argument is used, variable formatter preffers the type
of the varible parsed from a MIB file instead of checking type of the variable
as parsed from SNMP message.

This can lead to crashes when incoming packets contains a variable with
NULL type, while the MIB says the variable should be non-NULL, like Integer.
The formatter then tries to interpret the NULL (from packet) as Integer (from
MIB file).
diff --git a/snmplib/mib.c b/snmplib/mib.c
index 9d3ca41..c6e0010 100644
--- a/snmplib/mib.c
+++ b/snmplib/mib.c
@@ -439,17 +439,16 @@
     u_char         *cp;
     int             output_format, cnt;
 
-    if ((var->type != ASN_OCTET_STR) && 
-        (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT))) {
-        const char      str[] = "Wrong Type (should be OCTET STRING): ";
-        if (snmp_cstrcat
-            (buf, buf_len, out_len, allow_realloc, str)) {
-            return sprint_realloc_by_type(buf, buf_len, out_len,
+    if (var->type != ASN_OCTET_STR) {
+        if (!netsnmp_ds_get_boolean(
+                    NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT)) {
+            const char      str[] = "Wrong Type (should be OCTET STRING): ";
+            if (!snmp_cstrcat(buf, buf_len, out_len, allow_realloc, str))
+                return 0;
+        }
+        return sprint_realloc_by_type(buf, buf_len, out_len,
                                           allow_realloc, var, NULL, NULL,
                                           NULL);
-        } else {
-            return 0;
-        }
     }
 
 
@@ -702,16 +701,16 @@
                      const struct enum_list *enums,
                      const char *hint, const char *units)
 {
-    if ((var->type != ASN_OPAQUE_FLOAT) &&
-        (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT))) {
-        if (snmp_cstrcat(buf, buf_len, out_len, allow_realloc, 
-                         "Wrong Type (should be Float): ")) {
-            return sprint_realloc_by_type(buf, buf_len, out_len,
+    if (var->type != ASN_OPAQUE_FLOAT) {
+        if (!netsnmp_ds_get_boolean(
+                NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT)) {
+            u_char          str[] = "Wrong Type (should be Float): ";
+            if (!snmp_strcat(buf, buf_len, out_len, allow_realloc, str))
+                return 0;
+        }
+        return sprint_realloc_by_type(buf, buf_len, out_len,
                                           allow_realloc, var, NULL, NULL,
                                           NULL);
-        } else {
-            return 0;
-        }
     }
 
     if (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICK_PRINT)) {
@@ -772,17 +771,16 @@
                       const struct enum_list *enums,
                       const char *hint, const char *units)
 {
-    if ((var->type != ASN_OPAQUE_DOUBLE) && 
-        (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT))) {
-        if (snmp_cstrcat
-            (buf, buf_len, out_len, allow_realloc, 
-             "Wrong Type (should be Double): ")) {
-            return sprint_realloc_by_type(buf, buf_len, out_len,
+    if (var->type != ASN_OPAQUE_DOUBLE) {
+        if (!netsnmp_ds_get_boolean(
+                NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT)) {
+            u_char          str[] = "Wrong Type (should be Double): ";
+            if (!snmp_strcat(buf, buf_len, out_len, allow_realloc, str))
+                return 0;
+        }
+        return sprint_realloc_by_type(buf, buf_len, out_len,
                                           allow_realloc, var, NULL, NULL,
                                           NULL);
-        } else {
-            return 0;
-        }
     }
 
     if (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICK_PRINT)) {
@@ -847,20 +845,21 @@
 {
     char            a64buf[I64CHARSZ + 1];
 
-    if ((var->type != ASN_COUNTER64
+    if (var->type != ASN_COUNTER64
 #ifdef NETSNMP_WITH_OPAQUE_SPECIAL_TYPES
         && var->type != ASN_OPAQUE_COUNTER64
         && var->type != ASN_OPAQUE_I64 && var->type != ASN_OPAQUE_U64
 #endif
-        ) && (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT))) {
-        if (snmp_cstrcat(buf, buf_len, out_len, allow_realloc, 
-                        "Wrong Type (should be Counter64): ")) {
-            return sprint_realloc_by_type(buf, buf_len, out_len,
+        ) {
+        if (!netsnmp_ds_get_boolean(
+                NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT)) {
+            u_char          str[] = "Wrong Type (should be Counter64): ";
+            if (!snmp_strcat(buf, buf_len, out_len, allow_realloc, str))
+                return 0;
+        }
+        return sprint_realloc_by_type(buf, buf_len, out_len,
                                           allow_realloc, var, NULL, NULL,
                                           NULL);
-        } else {
-            return 0;
-        }
     }
 
     if (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICK_PRINT)) {
@@ -948,23 +947,25 @@
                       const struct enum_list *enums,
                       const char *hint, const char *units)
 {
-    if ((var->type != ASN_OPAQUE
+    if (var->type != ASN_OPAQUE
 #ifdef NETSNMP_WITH_OPAQUE_SPECIAL_TYPES
         && var->type != ASN_OPAQUE_COUNTER64
         && var->type != ASN_OPAQUE_U64
         && var->type != ASN_OPAQUE_I64
         && var->type != ASN_OPAQUE_FLOAT && var->type != ASN_OPAQUE_DOUBLE
 #endif                          /* NETSNMP_WITH_OPAQUE_SPECIAL_TYPES */
-        ) && (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT))) {
-        if (snmp_cstrcat(buf, buf_len, out_len, allow_realloc, 
-                         "Wrong Type (should be Opaque): ")) {
-            return sprint_realloc_by_type(buf, buf_len, out_len,
+        ) {
+        if (!netsnmp_ds_get_boolean(
+                NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT)) {
+            u_char          str[] = "Wrong Type (should be Opaque): ";
+            if (!snmp_strcat(buf, buf_len, out_len, allow_realloc, str))
+                return 0;
+        }
+        return sprint_realloc_by_type(buf, buf_len, out_len,
                                           allow_realloc, var, NULL, NULL,
                                           NULL);
-        } else {
-            return 0;
-        }
     }
+
 #ifdef NETSNMP_WITH_OPAQUE_SPECIAL_TYPES
     switch (var->type) {
     case ASN_OPAQUE_COUNTER64:
@@ -1040,17 +1041,16 @@
 {
     int             buf_overflow = 0;
 
-    if ((var->type != ASN_OBJECT_ID) &&
-        (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT))) {
-        u_char          str[] =
-            "Wrong Type (should be OBJECT IDENTIFIER): ";
-        if (snmp_strcat(buf, buf_len, out_len, allow_realloc, str)) {
-            return sprint_realloc_by_type(buf, buf_len, out_len,
+    if (var->type != ASN_OBJECT_ID) {
+        if (!netsnmp_ds_get_boolean(
+                NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT)) {
+            u_char          str[] = "Wrong Type (should be OBJECT IDENTIFIER): ";
+            if (!snmp_strcat(buf, buf_len, out_len, allow_realloc, str))
+                return 0;
+        }
+        return sprint_realloc_by_type(buf, buf_len, out_len,
                                           allow_realloc, var, NULL, NULL,
                                           NULL);
-        } else {
-            return 0;
-        }
     }
 
     if (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICK_PRINT)) {
@@ -1110,16 +1110,16 @@
 {
     char            timebuf[40];
 
-    if ((var->type != ASN_TIMETICKS) && 
-        (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT))) {
-        u_char          str[] = "Wrong Type (should be Timeticks): ";
-        if (snmp_strcat(buf, buf_len, out_len, allow_realloc, str)) {
-            return sprint_realloc_by_type(buf, buf_len, out_len,
+    if (var->type != ASN_TIMETICKS) {
+        if (!netsnmp_ds_get_boolean(
+                NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT)) {
+            u_char          str[] = "Wrong Type (should be Timeticks): ";
+            if (!snmp_strcat(buf, buf_len, out_len, allow_realloc, str))
+                return 0;
+        }
+        return sprint_realloc_by_type(buf, buf_len, out_len,
                                           allow_realloc, var, NULL, NULL,
                                           NULL);
-        } else {
-            return 0;
-        }
     }
 
     if (netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_NUMERIC_TIMETICKS)) {
@@ -1277,17 +1277,18 @@
 {
     char           *enum_string = NULL;
 
-    if ((var->type != ASN_INTEGER) && 
-        (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT))) {
-        u_char          str[] = "Wrong Type (should be INTEGER): ";
-        if (snmp_strcat(buf, buf_len, out_len, allow_realloc, str)) {
-            return sprint_realloc_by_type(buf, buf_len, out_len,
+    if (var->type != ASN_INTEGER) {
+        if (!netsnmp_ds_get_boolean(
+                NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT)) {
+            u_char          str[] = "Wrong Type (should be INTEGER): ";
+            if (!snmp_strcat(buf, buf_len, out_len, allow_realloc, str))
+                return 0;
+        }
+        return sprint_realloc_by_type(buf, buf_len, out_len,
                                           allow_realloc, var, NULL, NULL,
                                           NULL);
-        } else {
-            return 0;
-        }
     }
+
     for (; enums; enums = enums->next) {
         if (enums->value == *var->val.integer) {
             enum_string = enums->label;
@@ -1380,16 +1381,16 @@
 {
     char           *enum_string = NULL;
 
-    if ((var->type != ASN_UINTEGER) && 
-        (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT))) {
-        u_char          str[] = "Wrong Type (should be UInteger32): ";
-        if (snmp_strcat(buf, buf_len, out_len, allow_realloc, str)) {
-            return sprint_realloc_by_type(buf, buf_len, out_len,
+    if (var->type != ASN_UINTEGER) {
+        if (!netsnmp_ds_get_boolean(
+                NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT)) {
+            u_char          str[] = "Wrong Type (should be UInteger32): ";
+            if (!snmp_strcat(buf, buf_len, out_len, allow_realloc, str))
+                return 0;
+        }
+        return sprint_realloc_by_type(buf, buf_len, out_len,
                                           allow_realloc, var, NULL, NULL,
                                           NULL);
-        } else {
-            return 0;
-        }
     }
 
     for (; enums; enums = enums->next) {
@@ -1477,17 +1478,16 @@
 {
     char            tmp[32];
 
-    if ((var->type != ASN_GAUGE) && 
-        (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT))) {
-        u_char          str[] =
-            "Wrong Type (should be Gauge32 or Unsigned32): ";
-        if (snmp_strcat(buf, buf_len, out_len, allow_realloc, str)) {
-            return sprint_realloc_by_type(buf, buf_len, out_len,
+    if (var->type != ASN_GAUGE) {
+        if (!netsnmp_ds_get_boolean(
+                NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT)) {
+            u_char          str[] = "Wrong Type (should be Gauge32 or Unsigned32): ";
+            if (!snmp_strcat(buf, buf_len, out_len, allow_realloc, str))
+                return 0;
+        }
+        return sprint_realloc_by_type(buf, buf_len, out_len,
                                           allow_realloc, var, NULL, NULL,
                                           NULL);
-        } else {
-            return 0;
-        }
     }
 
     if (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICK_PRINT)) {
@@ -1550,16 +1550,16 @@
 {
     char            tmp[32];
 
-    if ((var->type != ASN_COUNTER) && 
-        (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT))) {
-        u_char          str[] = "Wrong Type (should be Counter32): ";
-        if (snmp_strcat(buf, buf_len, out_len, allow_realloc, str)) {
-            return sprint_realloc_by_type(buf, buf_len, out_len,
+    if (var->type != ASN_COUNTER) {
+        if (!netsnmp_ds_get_boolean(
+                NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT)) {
+            u_char          str[] = "Wrong Type (should be Counter32): ";
+            if (!snmp_strcat(buf, buf_len, out_len, allow_realloc, str))
+                return 0;
+        }
+        return sprint_realloc_by_type(buf, buf_len, out_len,
                                           allow_realloc, var, NULL, NULL,
                                           NULL);
-        } else {
-            return 0;
-        }
     }
 
     if (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICK_PRINT)) {
@@ -1613,16 +1613,16 @@
 {
     size_t          i;
 
-    if ((var->type != ASN_IPADDRESS) && 
-        (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT))) {
-        u_char          str[] = "Wrong Type (should be NetworkAddress): ";
-        if (snmp_strcat(buf, buf_len, out_len, allow_realloc, str)) {
-            return sprint_realloc_by_type(buf, buf_len, out_len,
+    if (var->type != ASN_IPADDRESS) {
+        if (!netsnmp_ds_get_boolean(
+                NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT)) {
+            u_char          str[] = "Wrong Type (should be NetworkAddress): ";
+            if (!snmp_strcat(buf, buf_len, out_len, allow_realloc, str))
+                return 0;
+        }
+        return sprint_realloc_by_type(buf, buf_len, out_len,
                                           allow_realloc, var, NULL, NULL,
                                           NULL);
-        } else {
-            return 0;
-        }
     }
 
     if (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICK_PRINT)) {
@@ -1679,16 +1679,16 @@
 {
     u_char         *ip = var->val.string;
 
-    if ((var->type != ASN_IPADDRESS) && 
-        (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT))) {
-        u_char          str[] = "Wrong Type (should be IpAddress): ";
-        if (snmp_strcat(buf, buf_len, out_len, allow_realloc, str)) {
-            return sprint_realloc_by_type(buf, buf_len, out_len,
+    if (var->type != ASN_IPADDRESS) {
+        if (!netsnmp_ds_get_boolean(
+                NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT)) {
+            u_char          str[] = "Wrong Type (should be IpAddress): ";
+            if (!snmp_strcat(buf, buf_len, out_len, allow_realloc, str))
+                return 0;
+        }
+        return sprint_realloc_by_type(buf, buf_len, out_len,
                                           allow_realloc, var, NULL, NULL,
                                           NULL);
-        } else {
-            return 0;
-        }
     }
 
     if (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICK_PRINT)) {
@@ -1737,20 +1737,20 @@
                     const struct enum_list *enums,
                     const char *hint, const char *units)
 {
-    if ((var->type != ASN_NULL) && 
-        (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT))) {
-        u_char          str[] = "Wrong Type (should be NULL): ";
-        if (snmp_strcat(buf, buf_len, out_len, allow_realloc, str)) {
-            return sprint_realloc_by_type(buf, buf_len, out_len,
+    if (var->type != ASN_NULL) {
+        if (!netsnmp_ds_get_boolean(
+                NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT)) {
+            u_char          str[] = "Wrong Type (should be NULL): ";
+            if (!snmp_strcat(buf, buf_len, out_len, allow_realloc, str))
+                return 0;
+        }
+        return sprint_realloc_by_type(buf, buf_len, out_len,
                                           allow_realloc, var, NULL, NULL,
                                           NULL);
-        } else {
-            return 0;
-        }
-    } else {
-        u_char          str[] = "NULL";
-        return snmp_strcat(buf, buf_len, out_len, allow_realloc, str);
     }
+
+    u_char          str[] = "NULL";
+    return snmp_strcat(buf, buf_len, out_len, allow_realloc, str);
 }
 
 
@@ -1785,16 +1785,16 @@
     u_char         *cp;
     char           *enum_string;
 
-    if ((var->type != ASN_BIT_STR && var->type != ASN_OCTET_STR) &&
-        (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT))) {
-        u_char          str[] = "Wrong Type (should be BITS): ";
-        if (snmp_strcat(buf, buf_len, out_len, allow_realloc, str)) {
-            return sprint_realloc_by_type(buf, buf_len, out_len,
+    if (var->type != ASN_BIT_STR && var->type != ASN_OCTET_STR) {
+        if (!netsnmp_ds_get_boolean(
+                NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT)) {
+            u_char          str[] = "Wrong Type (should be BITS): ";
+            if (!snmp_strcat(buf, buf_len, out_len, allow_realloc, str))
+                return 0;
+        }
+        return sprint_realloc_by_type(buf, buf_len, out_len,
                                           allow_realloc, var, NULL, NULL,
                                           NULL);
-        } else {
-            return 0;
-        }
     }
 
     if (netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICK_PRINT)) {
@@ -1869,16 +1869,16 @@
                            const struct enum_list *enums, const char *hint,
                            const char *units)
 {
-    if ((var->type != ASN_NSAP) && 
-        (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT))) {
-        u_char          str[] = "Wrong Type (should be NsapAddress): ";
-        if (snmp_strcat(buf, buf_len, out_len, allow_realloc, str)) {
-            return sprint_realloc_by_type(buf, buf_len, out_len,
+    if (var->type != ASN_NSAP) {
+        if (!netsnmp_ds_get_boolean(
+                NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICKE_PRINT)) {
+            u_char          str[] = "Wrong Type (should be NsapAddress): ";
+            if (!snmp_strcat(buf, buf_len, out_len, allow_realloc, str))
+                return 0;
+        }
+        return sprint_realloc_by_type(buf, buf_len, out_len,
                                           allow_realloc, var, NULL, NULL,
                                           NULL);
-        } else {
-            return 0;
-        }
     }
 
     if (!netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID, NETSNMP_DS_LIB_QUICK_PRINT)) {