Minor fixes

backend/nfqueue/nfqueue.cpp

@@ -138,9 +138,14 @@ class NetfilterQueue {
 
 		nlh_verdict = nfq_nlmsg_put(buf, NFQNL_MSG_VERDICT, ntohs(nfg->res_id));
 
-		#define PKT_OPS \
+		/*
+			This define allow to avoid to allocate new heap memory for each packet.
+			The code under this comment is replicated for ipv6 and ip
+			Better solutions are welcome. :)
+		*/
+		#define PKT_HANDLE 																						\
 		PDU *transport_layer = find_transport_layer(&packet); 													\
-		if(transport_layer->inner_pdu() == nullptr){ \
+		if(transport_layer->inner_pdu() == nullptr || transport_layer == nullptr){ 								\
 			nfq_nlmsg_verdict_put(nlh_verdict, ntohl(ph->packet_id), NF_ACCEPT );								\
 		}else{																									\
 			int size = transport_layer->inner_pdu()->size();													\
@@ -158,14 +163,15 @@ class NetfilterQueue {
 					nfq_nlmsg_verdict_put(nlh_verdict, ntohl(ph->packet_id), NF_DROP );							\
 				}																								\
 			}																									\
-		}\
+		}
 
+		// Check IP protocol version
 		if ( (((uint8_t*)payload)[0] & 0xf0) == 0x40 ){
 			IP packet = IP((uint8_t*)payload,plen);
-			PKT_OPS
+			PKT_HANDLE
 		}else{
 			IPv6 packet = IPv6((uint8_t*)payload,plen);
-			PKT_OPS
+			PKT_HANDLE
 		}	
 
 		/* example to set the connmark. First, start NFQA_CT section: */