Remove `struct ndpi_id_struct` (#1427)

Remove the last uses of `struct ndpi_id_struct`.
That code is not really used and it has not been updated for a very long
time: see #1279 for details.

Correlation among flows is achieved via LRU caches.

This change allows to further reduce memory consumption (see also
91bb77a8).

At nDPI 4.0 (more precisly, at a6b10cf, because memory stats
were wrong until that commit):
```
nDPI Memory statistics:
	nDPI Memory (once):      221.15 KB
	Flow Memory (per flow):  2.94 KB
```
Now:
```
nDPI Memory statistics:
	nDPI Memory (once):      235.27 KB
	Flow Memory (per flow):  688 B        <--------
```
i.e. memory usage per flow has been reduced by 77%.

Close #1279

1 files changed, 5 insertions, 241 deletions

diff --git a/src/lib/protocols/directconnect.c b/src/lib/protocols/directconnect.c
index 55a3f8145..ea418f36d 100644
--- a/src/lib/protocols/directconnect.c
+++ b/src/lib/protocols/directconnect.c
@@ -77,151 +77,23 @@ static void ndpi_int_directconnect_add_connection(struct ndpi_detection_module_s
 						  struct ndpi_flow_struct *flow,
 						  const u_int8_t connection_type)
 {
-
-  struct ndpi_packet_struct *packet = &ndpi_struct->packet;
-  struct ndpi_id_struct *src = flow->src;
-  struct ndpi_id_struct *dst = flow->dst;
-
   ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_DIRECTCONNECT, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI);
-
-  if(src != NULL) {
-    src->directconnect_last_safe_access_time = packet->current_time_ms;
-    if(connection_type == DIRECT_CONNECT_TYPE_PEER) {
-      if(packet->tcp != NULL
-	  && flow->setup_packet_direction != packet->packet_direction && src->detected_directconnect_port == 0) {
-	src->detected_directconnect_port = packet->tcp->source;
-	NDPI_LOG_DBG2(ndpi_struct, "DC tcp PORT %u for src\n", ntohs(src->detected_directconnect_port));
-      }
-      if(packet->udp != NULL && src->detected_directconnect_udp_port == 0) {
-	src->detected_directconnect_udp_port = packet->udp->source;
-	NDPI_LOG_DBG2(ndpi_struct, "DC udp PORT %u for src\n", ntohs(src->detected_directconnect_port));
-
-      }
-    }
-
-  }
-  if(dst != NULL) {
-    dst->directconnect_last_safe_access_time = packet->current_time_ms;
-    if(connection_type == DIRECT_CONNECT_TYPE_PEER) {
-      if(packet->tcp != NULL
-	  && flow->setup_packet_direction == packet->packet_direction && dst->detected_directconnect_port == 0) {
-	/* DST PORT MARKING CAN LEAD TO PORT MISSDETECTIONS
-	 * seen at large customer http servers, where someone has send faked DC tcp packets
-	 * to the server
-	 */
-
-	/*
-	  dst->detected_directconnect_port = packet->tcp->dest;
-	  NDPI_LOG_DBG2(ndpi_struct,
-	  	"DC tcp PORT %u for dst\n",
-		ntohs (dst->detected_directconnect_port));
-	*/
-      }
-    }
-  }
 }
 
 static void ndpi_search_directconnect_tcp(struct ndpi_detection_module_struct *ndpi_struct,
 					  struct ndpi_flow_struct *flow) {
   struct ndpi_packet_struct *packet = &ndpi_struct->packet;
 	
-  struct ndpi_id_struct *src = flow->src;
-  struct ndpi_id_struct *dst = flow->dst;
-
   if(flow->detected_protocol_stack[0] == NDPI_PROTOCOL_DIRECTCONNECT) {
     if(packet->payload_packet_len >= 40 && memcmp(&packet->payload[0], "BINF", 4) == 0) {
-      u_int16_t ssl_port = parse_binf_message(ndpi_struct,
-					      &packet->payload[4],
-					      packet->payload_packet_len - 4);
-      if(dst != NULL && ssl_port)
-	dst->detected_directconnect_ssl_port = ssl_port;
-      
-      if(src != NULL && ssl_port)
-	src->detected_directconnect_ssl_port = ssl_port;
+      parse_binf_message(ndpi_struct,
+			 &packet->payload[4],
+			 packet->payload_packet_len - 4);
     }
     
-    if((packet->payload_packet_len >= 38 && packet->payload_packet_len <= 42)
-	&& memcmp(&packet->payload[0], "DCTM", 4) == 0 && memcmp(&packet->payload[15], "ADCS", 4) == 0) {
-      u_int16_t bytes_read = 0;
-      if(dst != NULL) {
-	dst->detected_directconnect_ssl_port =
-	  ntohs_ndpi_bytestream_to_number(&packet->payload[25], 5, &bytes_read);
-	NDPI_LOG_DBG2(ndpi_struct, "DC ssl port parsed %d\n", ntohs(dst->detected_directconnect_ssl_port));
-      }
-      if(src != NULL) {
-	src->detected_directconnect_ssl_port =
-	  ntohs_ndpi_bytestream_to_number(&packet->payload[25], 5, &bytes_read);
-	NDPI_LOG_DBG2(ndpi_struct, "DC ssl port parsed %d\n", ntohs(src->detected_directconnect_ssl_port));
-      }
-
-
-    }
     return;
 
   }
-  if(src != NULL) {
-    if(src->detected_directconnect_port == packet->tcp->source) {
-      if((u_int32_t)
-	  (packet->current_time_ms -
-	   src->directconnect_last_safe_access_time) < ndpi_struct->directconnect_connection_ip_tick_timeout) {
-	src->directconnect_last_safe_access_time = packet->current_time_ms;
-	NDPI_LOG_INFO(ndpi_struct, "found DC using port %d\n", ntohs(src->detected_directconnect_port));
-	ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_DIRECTCONNECT, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI_SRC_DST_ID);
-	return;
-      } else {
-	src->detected_directconnect_port = 0;
-	NDPI_LOG_DBG2(ndpi_struct, "resetting src port due to timeout\n");
-	return;
-      }
-    }
-    if(src->detected_directconnect_ssl_port == packet->tcp->dest) {
-      if((u_int32_t)
-	  (packet->current_time_ms -
-	   src->directconnect_last_safe_access_time) < ndpi_struct->directconnect_connection_ip_tick_timeout) {
-	src->directconnect_last_safe_access_time = packet->current_time_ms;
-	NDPI_LOG_INFO(ndpi_struct, "found DC using port %d\n", ntohs(src->detected_directconnect_ssl_port));
-	ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_DIRECTCONNECT, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI_SRC_DST_ID);
-	return;
-      } else {
-	src->detected_directconnect_ssl_port = 0;
-	NDPI_LOG_DBG2(ndpi_struct, "resetting src port due to timeout\n");
-	return;
-      }
-    }
-
-  }
-
-  if(dst != NULL) {
-    if(dst->detected_directconnect_port == packet->tcp->dest) {
-      if((u_int32_t)
-	  (packet->current_time_ms -
-	   dst->directconnect_last_safe_access_time) < ndpi_struct->directconnect_connection_ip_tick_timeout) {
-	dst->directconnect_last_safe_access_time = packet->current_time_ms;
-	NDPI_LOG_INFO(ndpi_struct, "found DC using port %d\n", ntohs(dst->detected_directconnect_port));
-	ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_DIRECTCONNECT, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI_SRC_DST_ID);
-	return;
-      } else {
-	dst->detected_directconnect_port = 0;
-	NDPI_LOG_DBG(ndpi_struct, "resetting dst port due to timeout\n");
-	return;
-      }
-    }
-    if(dst->detected_directconnect_ssl_port == packet->tcp->dest) {
-      if((u_int32_t)
-	  (packet->current_time_ms -
-	   dst->directconnect_last_safe_access_time) < ndpi_struct->directconnect_connection_ip_tick_timeout) {
-	dst->directconnect_last_safe_access_time = packet->current_time_ms;
-	NDPI_LOG_DBG(ndpi_struct, "found DC using port %d\n", ntohs(dst->detected_directconnect_ssl_port));
-	ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_DIRECTCONNECT, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI_SRC_DST_ID);
-	return;
-      } else {
-	dst->detected_directconnect_ssl_port = 0;
-	NDPI_LOG_DBG2(ndpi_struct, "resetting dst port due to timeout\n");
-	return;
-      }
-    }
-
-  }
 
   if(flow->directconnect_stage == 0) {
 
@@ -308,124 +180,15 @@ static void ndpi_search_directconnect_tcp(struct ndpi_detection_module_struct *n
 
 }
 
-static void ndpi_search_directconnect_udp(struct ndpi_detection_module_struct
-					  *ndpi_struct, struct ndpi_flow_struct *flow)
-{
-  struct ndpi_packet_struct *packet = &ndpi_struct->packet;
-	
-  struct ndpi_id_struct *src = flow->src;
-  struct ndpi_id_struct *dst = flow->dst;
-  int pos, count = 0;
-
-  if(dst != NULL && dst->detected_directconnect_udp_port == packet->udp->dest) {
-    if((u_int32_t)
-	(packet->current_time_ms -
-	 dst->directconnect_last_safe_access_time) < ndpi_struct->directconnect_connection_ip_tick_timeout) {
-
-      dst->directconnect_last_safe_access_time = packet->current_time_ms;
-      NDPI_LOG_INFO(ndpi_struct, "found DC using udp port %d\n", ntohs(dst->detected_directconnect_udp_port));
-      ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_DIRECTCONNECT, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI_SRC_DST_ID);
-      return;
-    } else {
-      dst->detected_directconnect_udp_port = 0;
-      NDPI_LOG_DBG2(ndpi_struct, "resetting dst udp  port due to timeout\n");
-      return;
-    }
-  }
-
-  if(packet->payload_packet_len > 58) {
-    if(src != NULL
-	&& NDPI_COMPARE_PROTOCOL_TO_BITMASK(src->detected_protocol_bitmask, NDPI_PROTOCOL_DIRECTCONNECT)) {
-      if(packet->payload[0] == '$'
-	  && packet->payload[packet->payload_packet_len - 1] == '|'
-	  && memcmp(&packet->payload[1], "SR ", 3) == 0) {
-	pos = packet->payload_packet_len - 2;
-	if(packet->payload[pos] == ')') {
-	  while (pos > 0 && packet->payload[pos] != '(' && count < 21) {
-	    pos--;
-	    count++;
-	  }
-	  if(packet->payload[pos] == '(') {
-	    pos = pos - 44;
-	    if(pos > 2 && memcmp(&packet->payload[pos], "TTH:", 4) == 0) {
-	      NDPI_LOG_INFO(ndpi_struct, "found DC udp\n");
-	      ndpi_int_directconnect_add_connection(ndpi_struct, flow, DIRECT_CONNECT_TYPE_PEER);
-	      return;
-	    }
-	  }
-	}
-	flow->directconnect_stage++;
-	if(flow->directconnect_stage < 3) 
-	  return;
-      }
-
-    }
-    if(dst != NULL
-	&& NDPI_COMPARE_PROTOCOL_TO_BITMASK(dst->detected_protocol_bitmask, NDPI_PROTOCOL_DIRECTCONNECT)) {
-      if(packet->payload[0] == '$'
-	  && packet->payload[packet->payload_packet_len - 1] == '|'
-	  && memcmp(&packet->payload[1], "SR ", 3) == 0) {
-	pos = packet->payload_packet_len - 2;
-	if(packet->payload[pos] == ')') {
-	  while (pos > 0 && packet->payload[pos] != '(' && count < 21) {
-	    pos--;
-	    count++;
-	  }
-	  if(packet->payload[pos] == '(') {
-	    pos = pos - 44;
-	    if(pos > 2 && memcmp(&packet->payload[pos], "TTH:", 4) == 0) {
-	      NDPI_LOG_INFO(ndpi_struct, "found DC udp\n");
-	      ndpi_int_directconnect_add_connection(ndpi_struct, flow, DIRECT_CONNECT_TYPE_PEER);
-	      return;
-	    }
-	  }
-	}
-	flow->directconnect_stage++;
-	if(flow->directconnect_stage < 3)
-	  return;
-      }
-    }
-
-  }
-  NDPI_LOG_DBG(ndpi_struct, "excluded DC at stage %d \n", flow->directconnect_stage);
-
-  NDPI_ADD_PROTOCOL_TO_BITMASK(flow->excluded_protocol_bitmask, NDPI_PROTOCOL_DIRECTCONNECT);
-
-
-}
-
 void ndpi_search_directconnect(struct ndpi_detection_module_struct
 			       *ndpi_struct, struct ndpi_flow_struct *flow)
 {
   struct ndpi_packet_struct *packet = &ndpi_struct->packet;
-  struct ndpi_id_struct *src = flow->src;
-  struct ndpi_id_struct *dst = flow->dst;
 
   NDPI_LOG_DBG(ndpi_struct, "search DC\n");
 
-  if(flow->detected_protocol_stack[0] == NDPI_PROTOCOL_DIRECTCONNECT) {
-    if(src != NULL && ((u_int32_t)
-			(packet->current_time_ms -
-			 src->directconnect_last_safe_access_time) <
-			ndpi_struct->directconnect_connection_ip_tick_timeout)) {
-      src->directconnect_last_safe_access_time = packet->current_time_ms;
-
-    } else if(dst != NULL && ((u_int32_t)
-			       (packet->current_time_ms -
-				dst->directconnect_last_safe_access_time) <
-			       ndpi_struct->directconnect_connection_ip_tick_timeout)) {
-      dst->directconnect_last_safe_access_time = packet->current_time_ms;
-    } else {
-      ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_UNKNOWN, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_UNKNOWN);
-      NDPI_LOG_DBG2(ndpi_struct, "skipping as unknown due to timeout\n");
-    }
-    return;
-  }
-
   if(packet->tcp != NULL) {
     ndpi_search_directconnect_tcp(ndpi_struct, flow);
-  } else if(packet->udp != NULL) {
-    ndpi_search_directconnect_udp(ndpi_struct, flow);
   }
 }
 
@@ -435,7 +198,8 @@ void init_directconnect_dissector(struct ndpi_detection_module_struct *ndpi_stru
   ndpi_set_bitmask_protocol_detection("DirectConnect", ndpi_struct, detection_bitmask, *id,
 				      NDPI_PROTOCOL_DIRECTCONNECT,
 				      ndpi_search_directconnect,
-				      NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_OR_UDP_WITH_PAYLOAD_WITHOUT_RETRANSMISSION,
+				      /* TODO: UDP?*/
+				      NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_WITH_PAYLOAD_WITHOUT_RETRANSMISSION,
 				      SAVE_DETECTION_BITMASK_AS_UNKNOWN,
 				      ADD_TO_DETECTION_BITMASK);