Use (or define) a macro for the real size of PACKET_OID_DATA

Author: bonsaiviking

pcap-npf.c

@@ -185,6 +185,10 @@ PacketGetMonitorMode(PCHAR AdapterName _U_)
 #define NDIS_STATUS_NOT_SUPPORTED	0xc00000bb	/* STATUS_NOT_SUPPORTED */
 #define NDIS_STATUS_NOT_RECOGNIZED	0x00010001
 
+#ifndef PACKET_OID_DATA_LENGTH
+#define PACKET_OID_DATA_LENGTH(_DataLength) \
+	(offsetof(PACKET_OID_DATA, Data) + _DataLength)
+#endif
 static int
 oid_get_request(ADAPTER *adapter, bpf_u_int32 oid, void *data, size_t *lenp,
     char *errbuf)
@@ -193,12 +197,9 @@ oid_get_request(ADAPTER *adapter, bpf_u_int32 oid, void *data, size_t *lenp,
 
 	/*
 	 * Allocate a PACKET_OID_DATA structure to hand to PacketRequest().
-	 * It should be big enough to hold "*lenp" bytes of data; it
-	 * will actually be slightly larger, as PACKET_OID_DATA has a
-	 * 1-byte data array at the end, standing in for the variable-length
-	 * data that's actually there.
+	 * It should be big enough to hold "*lenp" bytes of data;
 	 */
-	oid_data_arg = malloc(sizeof (PACKET_OID_DATA) + *lenp);
+	oid_data_arg = malloc(PACKET_OID_DATA_LENGTH(*lenp));
 	if (oid_data_arg == NULL) {
 		snprintf(errbuf, PCAP_ERRBUF_SIZE,
 		    "Couldn't allocate argument buffer for PacketRequest");
@@ -393,12 +394,9 @@ pcap_oid_set_request_npf(pcap_t *p, bpf_u_int32 oid, const void *data,
 
 	/*
 	 * Allocate a PACKET_OID_DATA structure to hand to PacketRequest().
-	 * It should be big enough to hold "*lenp" bytes of data; it
-	 * will actually be slightly larger, as PACKET_OID_DATA has a
-	 * 1-byte data array at the end, standing in for the variable-length
-	 * data that's actually there.
+	 * It should be big enough to hold "*lenp" bytes of data;
 	 */
-	oid_data_arg = malloc(sizeof (PACKET_OID_DATA) + *lenp);
+	oid_data_arg = malloc(PACKET_OID_DATA_LENGTH(*lenp));
 	if (oid_data_arg == NULL) {
 		snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 		    "Couldn't allocate argument buffer for PacketRequest");