TCP bug fix, TCP refactoring

sys/net/destiny/socket.c

@@ -13,6 +13,38 @@
 #include "socket.h"
 #include "sys/net/net_help/net_help.h"
 
+void print_tcp_flags (tcp_hdr_t *tcp_header)
+	{
+	printf("FLAGS: ");
+	if ((tcp_header->reserved_flags & TCP_ACK) > 0)
+		{
+		printf("ACK ");
+		}
+	if ((tcp_header->reserved_flags & TCP_RST) > 0)
+		{
+		printf("RST ");
+		}
+	if ((tcp_header->reserved_flags & TCP_SYN) > 0)
+		{
+		printf("SYN ");
+		}
+	if ((tcp_header->reserved_flags & TCP_FIN) > 0)
+		{
+		printf("FIN ");
+		}
+	printf("\n\n");
+	}
+
+void print_tcp_status(int in_or_out, ipv6_hdr_t *ipv6_header, tcp_hdr_t *tcp_header)
+	{
+	printf("--- %s TCP packet: ---\n", (in_or_out == INC_PACKET ? "Incoming" : "Outgoing"));
+	ipv6_print_addr(&ipv6_header->srcaddr);
+	ipv6_print_addr(&ipv6_header->destaddr);
+	printf("Source Port: %i, Dest. Port: %i\n", tcp_header->src_port, tcp_header->dst_port);
+	printf("ACK: %li, SEQ: %li, Window: %i\n", tcp_header->ack_nr, tcp_header->seq_nr, tcp_header->window);
+	print_tcp_flags(tcp_header);
+	}
+
 void print_socket(uint8_t socket)
 	{
 	socket_internal_t *current_socket_internal = &sockets[socket - 1];
@@ -271,6 +303,26 @@ void set_tcp_packet(tcp_hdr_t *tcp_hdr, uint16_t src_port, uint16_t dst_port, ui
 	tcp_hdr->window					= window;
 	}
 
+// Check for consistent ACK and SEQ number
+// TODO: Use error codes for different kinds of inconsistency when needed!
+int check_tcp_consistency(socket_t *current_tcp_socket, tcp_hdr_t *tcp_header)
+	{
+	if (IS_TCP_ACK(tcp_header->reserved_flags))
+		{
+		if(tcp_header->ack_nr != (current_tcp_socket->local_tcp_status.seq_nr+1))
+			{
+			// TODO: possible loss of a packet (MAYBE!)
+			return -1;
+			}
+		}
+	if (tcp_header->seq_nr <= current_tcp_socket->foreign_tcp_status.seq_nr)
+		{
+		// TODO: possible repetition of a packet or wrong order of arriving
+		return -1;
+		}
+	return 1;
+	}
+
 int connect(int socket, sockaddr6_t *addr, uint32_t addrlen, uint8_t tcp_client_thread)
 	{
 	// Variables
@@ -310,8 +362,6 @@ int connect(int socket, sockaddr6_t *addr, uint32_t addrlen, uint8_t tcp_client_
 	// Fill TCP SYN packet
 	set_tcp_packet(current_tcp_packet, current_tcp_socket->local_address.sin6_port, current_tcp_socket->foreign_address.sin6_port,
 			current_tcp_socket->local_tcp_status.seq_nr, 0, 0, TCP_SYN, current_tcp_socket->local_tcp_status.window, 0, 0);
-	printf("PORT orig: %i, PORT socket: %i\n", addr->sin6_port, current_tcp_socket->foreign_address.sin6_port);
-	printTCPHeader(current_tcp_packet);
 	// Fill IPv6 Header
 	memcpy(&(temp_ipv6_header->destaddr), &current_tcp_socket->foreign_address.sin6_addr, 16);
 	memcpy(&(temp_ipv6_header->srcaddr), &current_tcp_socket->local_address.sin6_addr, 16);
@@ -326,7 +376,13 @@ int connect(int socket, sockaddr6_t *addr, uint32_t addrlen, uint8_t tcp_client_
 	msg_receive(&msg_from_server);
 
 	// Read packet content
-	tcp_hdr_t *tcp_header = ((tcp_hdr_t*)(msg_from_server.content.ptr+IPV6_HDR_LEN));
+	tcp_hdr_t *tcp_header = ((tcp_hdr_t*)(buffer_tcp+IPV6_HDR_LEN));
+
+	// Check for consistency
+	if (check_tcp_consistency(current_tcp_socket, tcp_header) == -1)
+		{
+		printf("TCP packets not consistent!\n");
+		}
 
 	// Got SYN ACK from Server
 	// Refresh foreign TCP socket information
@@ -584,8 +640,14 @@ int handle_new_tcp_connection(socket_t *current_queued_socket, socket_internal_t
 	ipv6_hdr_t *ipv6_header;
 	tcp_hdr_t *tcp_header;
 
-	ipv6_header = ((ipv6_hdr_t*)(msg_recv_client_ack.content.ptr));
+	ipv6_header = ((ipv6_hdr_t*)(buffer_tcp));
-	tcp_header = ((tcp_hdr_t*)(msg_recv_client_ack.content.ptr));
+	tcp_header = ((tcp_hdr_t*)(buffer_tcp+IPV6_HDR_LEN));
+
+	// Check for consistency
+	if (check_tcp_consistency(current_queued_socket, tcp_header) == -1)
+		{
+		printf("TCP packets not consistent!\n");
+		}
 
 	// Got ack, connection established, refresh local and foreign tcp socket status
 	set_tcp_status(&current_queued_socket->foreign_tcp_status, tcp_header->ack_nr, STATIC_MSS, tcp_header->seq_nr, ESTABLISHED, tcp_header->window);

sys/net/destiny/socket.h

@@ -113,6 +113,9 @@
 #define STATIC_MSS			32
 #define STATIC_WINDOW		32
 
+#define INC_PACKET			0
+#define OUT_PACKET			1
+
 typedef struct __attribute__ ((packed)) socka6
 	{
     uint8_t     		sin6_family;    		/* AF_INET6 */
@@ -161,5 +164,6 @@ void print_sockets(void);
 void print_socket(uint8_t socket);
 bool exists_socket(uint8_t socket);
 socket_t *new_tcp_queued_socket(ipv6_hdr_t *ipv6_header, tcp_hdr_t *tcp_header, socket_internal_t *socket);
+void print_tcp_status(int in_or_out, ipv6_hdr_t *ipv6_header, tcp_hdr_t *tcp_header);
 
 #endif /* SOCKET_H_ */

sys/net/destiny/tcp.c

@@ -51,9 +51,69 @@ uint16_t tcp_csum(ipv6_hdr_t *ipv6_header, tcp_hdr_t *tcp_header)
     return (sum == 0) ? 0xffff : HTONS(sum);
 	}
 
+void handle_tcp_ack_packet(ipv6_hdr_t *ipv6_header, tcp_hdr_t *tcp_header, socket_internal_t *tcp_socket)
+	{
+	msg_t m_recv_tcp, m_send_tcp;
+	if (getWaitingConnectionSocket(tcp_socket->socket_id)->local_tcp_status.state == SYN_RCVD)
+		{
+		msg_send_receive(&m_send_tcp, &m_recv_tcp, tcp_socket->pid);
+		}
+	}
+
+void handle_tcp_rst_packet(ipv6_hdr_t *ipv6_header, tcp_hdr_t *tcp_header, socket_internal_t *tcp_socket)
+	{
+
+	}
+
+void handle_tcp_syn_packet(ipv6_hdr_t *ipv6_header, tcp_hdr_t *tcp_header, socket_internal_t *tcp_socket)
+	{
+	msg_t m_send_tcp;
+	if (tcp_socket->in_socket.local_tcp_status.state == LISTEN)
+		{
+		socket_t *new_socket = new_tcp_queued_socket(ipv6_header, tcp_header, tcp_socket);
+		if (new_socket != NULL)
+			{
+			// notify socket function accept(..) that a new connection request has arrived
+			// No need to wait for an answer because the server accept() function isnt reading from anything other than the queued sockets
+			msg_send(&m_send_tcp, tcp_socket->pid, 0);
+			}
+		else
+			{
+			printf("Dropped TCP SYN Message because an error occured while requesting a new queued socket!\n");
+			}
+		}
+	else
+		{
+		printf("Droppec TCP SYN Message because socket was not in state LISTEN!");
+		}
+	}
+
+void handle_tcp_syn_ack_packet(ipv6_hdr_t *ipv6_header, tcp_hdr_t *tcp_header, socket_internal_t *tcp_socket)
+	{
+	msg_t m_recv_tcp, m_send_tcp;
+	if (tcp_socket->in_socket.local_tcp_status.state == SYN_SENT)
+		{
+		msg_send_receive(&m_send_tcp, &m_recv_tcp, tcp_socket->pid);
+		}
+	else
+		{
+		printf("Socket not in state SYN_SENT, dropping SYN-ACK-packet!");
+		}
+	}
+
+void handle_tcp_fin_packet(ipv6_hdr_t *ipv6_header, tcp_hdr_t *tcp_header, socket_internal_t *tcp_socket)
+	{
+
+	}
+
+void handle_tcp_fin_ack_packet(ipv6_hdr_t *ipv6_header, tcp_hdr_t *tcp_header, socket_internal_t *tcp_socket)
+	{
+
+	}
+
 void tcp_packet_handler (void)
 	{
-	msg_t m_recv_ip, m_send_ip, m_recv_tcp, m_send_tcp;
+	msg_t m_recv_ip, m_send_ip;
 	ipv6_hdr_t *ipv6_header;
 	tcp_hdr_t *tcp_header;
 	uint8_t *payload;
@@ -66,12 +126,14 @@ void tcp_packet_handler (void)
 		ipv6_header = ((ipv6_hdr_t*)&buffer_tcp);
 		tcp_header = ((tcp_hdr_t*)(&buffer_tcp[IPV6_HDR_LEN]));
 		payload = &buffer_tcp[IPV6_HDR_LEN+TCP_HDR_LEN];
-		printTCPHeader(tcp_header);
+		//printTCPHeader(tcp_header);
 		chksum = tcp_csum(ipv6_header, tcp_header);
 		printf("Checksum is %x!\n", chksum);
 
 		tcp_socket = get_tcp_socket(ipv6_header, tcp_header);
 
+		print_tcp_status(INC_PACKET, ipv6_header, tcp_header);
+
 		if ((chksum == 0xffff) && (tcp_socket != NULL))
 			{
 			// Remove reserved bits from tcp flags field
@@ -83,69 +145,41 @@ void tcp_packet_handler (void)
 				case TCP_ACK:
 					{
 					// only ACK Bit set
-					if (getWaitingConnectionSocket(tcp_socket->socket_id)->local_tcp_status.state == SYN_RCVD)
+					handle_tcp_ack_packet(ipv6_header, tcp_header, tcp_socket);
-						{
-						m_send_tcp.content.ptr = (char*)buffer;
-						m_send_tcp.content.value = IPV6_HDR_LEN + ipv6_header->length;
-						msg_send_receive(&m_recv_tcp, &m_send_tcp, tcp_socket->pid);
-						}
 					break;
 					}
 				case TCP_RST:
 					{
 					printf("RST Bit set!\n");
 					// only RST Bit set
+					handle_tcp_rst_packet(ipv6_header, tcp_header, tcp_socket);
 					break;
 					}
 				case TCP_SYN:
 					{
 					// only SYN Bit set, look for matching, listening socket and request new queued socket
 					printf("SYN Bit set!\n");
-					if (tcp_socket->in_socket.local_tcp_status.state == LISTEN)
+					handle_tcp_syn_packet(ipv6_header, tcp_header, tcp_socket);
-						{
-						socket_t *new_socket = new_tcp_queued_socket(ipv6_header, tcp_header, tcp_socket);
-						if (new_socket != NULL)
-							{
-							// notify socket function accept(..) that a new connection request has arrived
-							// No need to wait for an answer because the server accept() function isnt reading from anything other than the queued sockets
-							msg_send(&m_send_tcp, tcp_socket->pid, 0);
-							}
-						else
-							{
-							printf("Dropped TCP SYN Message because an error occured while requesting a new queued socket!\n");
-							}
-						}
-					else
-						{
-						printf("Droppec TCP SYN Message because socket was not in state LISTEN!");
-						}
 					break;
 					}
 				case TCP_SYN_ACK:
 					{
 					// only SYN and ACK Bit set, complete three way handshake when socket in state SYN_SENT
-					if (tcp_socket->in_socket.local_tcp_status.state == SYN_SENT)
+					handle_tcp_syn_ack_packet(ipv6_header, tcp_header, tcp_socket);
-						{
-						m_send_tcp.content.ptr = (char*)buffer;
-						m_send_tcp.content.value = IPV6_HDR_LEN + ipv6_header->length;
-						msg_send_receive(&m_recv_tcp, &m_send_tcp, tcp_socket->pid);
-						}
-					else
-						{
-						printf("Socket not in state SYN_SENT, dropping SYN-ACK-packet!");
-						}
 					break;
 					}
 				case TCP_FIN:
 					{
 					printf("FIN Bit set!\n");
 					// only FIN Bit set
+					handle_tcp_fin_packet(ipv6_header, tcp_header, tcp_socket);
 					break;
 					}
 				case TCP_FIN_ACK:
 					{
 					printf("FIN ACK Bit set!\n");
 					// only FIN and ACK Bit set
+					handle_tcp_fin_ack_packet(ipv6_header, tcp_header, tcp_socket);
 					break;
 					}
 				default: