tcp_ip.h

适用于8位小型嵌入式系统的TCP/IP协议栈！！移植非常方便！

/*
 *Copyright (c) 2000-2002 Viola Systems Ltd.
 *All rights reserved.
 *
 *Redistribution and use in source and binary forms, with or without 
 *modification, are permitted provided that the following conditions 
 *are met:
 *
 *1. Redistributions of source code must retain the above copyright 
 *notice, this list of conditions and the following disclaimer.
 *
 *2. Redistributions in binary form must reproduce the above copyright 
 *notice, this list of conditions and the following disclaimer in the 
 *documentation and/or other materials provided with the distribution.
 *
 *3. The end-user documentation included with the redistribution, if 
 *any, must include the following acknowledgment:
 *	"This product includes software developed by Viola 
 *	Systems (http://www.violasystems.com/)."
 *
 *Alternately, this acknowledgment may appear in the software itself, 
 *if and wherever such third-party acknowledgments normally appear.
 *
 *4. The names "OpenTCP" and "Viola Systems" must not be used to 
 *endorse or promote products derived from this software without prior 
 *written permission. For written permission, please contact 
 *[e-mail].
 *
 *5. Products derived from this software may not be called "OpenTCP", 
 *nor may "OpenTCP" appear in their name, without prior written 
 *permission of the Viola Systems Ltd.
 *
 *THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESSED OR IMPLIED 
 *WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
 *MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
 *IN NO EVENT SHALL VIOLA SYSTEMS LTD. OR ITS CONTRIBUTORS BE LIABLE 
 *FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
 *CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
 *SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 
 *BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
 *WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 
 *OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, 
 *EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *====================================================================
 *
 *OpenTCP is the unified open source TCP/IP stack available on a series 
 *of 8/16-bit microcontrollers, please see <http://www.opentcp.org>.
 *
 *For more information on how to network-enable your devices, or how to 
 *obtain commercial technical support for OpenTCP, please see 
 *<http://www.violasystems.com/>.
 */

/** \file tcp_ip.h
 *	\brief OpenTCP ARP interface file
 *	\author 
 *		\li Jari Lahti ([e-mail])
 *	\version 1.0
 *	\date 1.2.2002
 * 	
 *	OpenTCP TCP and UDP protocol function declarations, constants, etc. 
 */

#ifndef INCLUDE_TCP_IP_H
#define INCLUDE_TCP_IP_H

#include <inet/datatypes.h>
#include <inet/ethernet.h>
#include <inet/ip.h>

/* User define			*/

/** \def NO_OF_TCPSOCKETS
 *	\ingroup opentcp_config
 *	\brief Defines number of TCP sockets available
 *
 *	Change this number to change maximum number of TCP sockets available
 *	to the application.
 *
 */
#define NO_OF_TCPSOCKETS	8

/** \def NO_OF_UDPSOCKETS
 *	\ingroup opentcp_config
 *	\brief Defines number of UDP sockets available
 *
 *	Change this number to change maximum number of UDP sockets available
 *	to the application.
 *
 */
#define NO_OF_UDPSOCKETS	4

/** \def TCP_PORTS_END
 *	\ingroup opentcp_config
 *	\brief Define reserved-ports space
 *
 *	TCP socket numbers will only be assigned to be lower than this 
 *	number. 
 */
#define TCP_PORTS_END		1023

/** \def UDP_PORTS_END
 *	\ingroup opentcp_config
 *	\brief Define reserved-ports space
 *
 *	UDP socket numbers will only be assigned to be lower than this 
 *	number. 
 */
#define UDP_PORTS_END			1023					

/* UDP Control optios			*/

/** \def UDP_OPT_NONE
 *	\brief Disable checksum calculation for UDP socket
 *
 *	By choosing only this option for UDP socket, checksum calculation 
 *	will be disabled for both incoming/outgoing UDP packets. This will
 *	make UDP extremely fast, but also more prone to errors. This is usually
 *	not a big limitation considering that checksum is not so good in
 *	error-detection anyway.
 */
#define UDP_OPT_NONE		0

/** \def UDP_OPT_SEND_CS
 *	\brief Enable checksum calculation for outgoing UDP packets
 *
 *	When only this option is chosen, checksum is calculated for outgoing
 *	UDP packets. This is sometimes neccessary since certain applications
 *	can disable reception of UDP packets without a calculated checksum.
 *
 */
#define UDP_OPT_SEND_CS		1

/** \def UDP_OPT_CHECK_CS
 *	\brief Enable checksum checking for received UDP packets
 *
 *	When this option is enabled, checksum is checked for all received
 *	UDP packets to check for transmission errors.
 */
#define UDP_OPT_CHECK_CS	2

#define UDP_SEND_MTU		ETH_MTU - ETH_HEADER_LEN - UDP_HLEN - IP_MAX_HLEN

#define UDP_HLEN			8				/**< UDP Header Length			*/

#define	MIN_TCP_HLEN		20
#define	MAX_TCP_OPTLEN		40				
#define TCP_DEF_MTU			512				/* Default MTU for TCP			*/

/** \def TCP_DEF_RETRIES
 *	\ingroup opentcp_config
 *	\brief Number of attempted TCP retransmissions before giving up
 *
 *	This number defines how many times will TCP module try to retransmit
 *	the data before recognizing that connection was broken. Increase this
 *	value for high-latency, low-throughput networks with substantial packet
 *	loss.
 *
 */
#define	TCP_DEF_RETRIES		7			

/** \def TCP_DEF_KEEPALIVE
 *	\ingroup opentcp_config
 *	\brief Defines a number of  seconds after which an empty ACK packet is sent
 *
 *	If for TCP_DEF_KEEPALIVE seconds nothing is received/sent over the
 *	TCP connection (this includes received empty TCP packets) an empty
 *	(keep-alive) TCP packet will be sent to check if the other side is 
 *	still replying (and able to reply).
 */
#define	TCP_DEF_KEEPALIVE	4			

/** \def TCP_DEF_RETRY_TOUT
 *	\ingroup opentcp_config
 *	\brief Default data-retransmission period (in seconds)
 *
 *	If data was not acknowledged during the time-frame defined by this
 *	value (in seconds) retransmission procedure will occur.
 */
#define TCP_DEF_RETRY_TOUT	2

/** \def TCP_TOS_NORMAL
 *	\brief Defines normal type of service for TCP socket
 *
 *	This defines normal (and for now the only one implemented) type of
 *	service for the TCP socket.
 */
#define TCP_TOS_NORMAL		0

/** \def TCP_DEF_TOUT
 *	\ingroup opentcp_config
 *	\brief Default idle timeout
 *
 *	This period defines idle timeout in seconds - this feature allows
 *	TCP/IP stack to close the TCP connection if no data has been exchanged
 *	over it during this period of time. This relates ONLY to data. Empty
 *	keep-alive TCP packets are not included.
 */
#define TCP_DEF_TOUT		120				

#define TCP_HALF_SEQ_SPACE	0x0000FFFF		/* For detecting sequence space	*/


/* ICMP message types */

#define ICMP_TYPE_DEST_UNREACHABLE	3
#define ICMP_ECHO_REQUEST	8
#define ICMP_ECHO_REPLY		0
#define ICMP_CODE_FRAGMENTATION_NEEDED_DF_SET	4
#define ICMP_MTUMSG_LEN	16
#define ICMP_ECHOREQ_HLEN	8
#define ICMP_TEMPIPSET_DATALEN	102


/* UDP States					*/

/** \def UDP_STATE_FREE
 *	\brief Defines that UDP socket is free and available
 *	
 *	If an entry of ucb type has this as a state value, then it is free
 *	and can be allocated by the udp_getsocket().
 */
#define UDP_STATE_FREE			1

/** \def UDP_STATE_CLOSED
 *	\brief Defines that UDP socket is allocated but closed
 *
 *	Entries of ucb type that have this as their state value were
 *	allocated by udp_getsocket() but they are in the closed state,
 *	so no data can be received/sent through the socket.
 */
#define UDP_STATE_CLOSED		2

/** \def UDP_STATE_OPENED
 *	\brief Defines that UDP socket is allocated and opened
 *
 *	Corresponding UDP socket was allocated and opened so data
 *	can be transmitted/received through it.
 */
#define UDP_STATE_OPENED		3

/* UDP Events					*/

/** \def UDP_EVENT_DATA
 *	\brief Only UDP event notified to UDP socket event listener
 *
 *	For now, this is the only UDP event that is notified to the
 *	UDP sockets' event listener.
 */
#define UDP_EVENT_DATA			64


/* TCP FLAGS					*/

#define	TCP_FLAG_ACK			0x10
#define TCP_FLAG_PUSH			0x08
#define TCP_FLAG_RESET			0x04
#define TCP_FLAG_SYN			0x02
#define TCP_FLAG_FIN			0x01

/* TCP Internal flags			*/

#define TCP_INTFLAGS_CLOSEPENDING	0x01

/* TCP socket types				*/
/** \def TCP_TYPE_NONE
 *	\brief TCP socket is nor a client nor a server
 *
 *	If TCP socket entry is of this type it can not be used for anything. 
 *	This may only be used for testing, debugging, etc. purposes or if 
 *	application is not sure what it wants to be it can reserve a TCP 
 *	socket by getting a socket of type TCP_TYPE_NONE.
 */
#define	TCP_TYPE_NONE			0x00

/** \def TCP_TYPE_SERVER
 *	\brief TCP socket represents a server application
 *
 *	If TCP socket entry is of server type, application using it can only
 *	listen on a given socket for incoming connections. No connections
 *	can be opened towards some outside host unless the outside host
 *	initiates the connection.
 */
#define	TCP_TYPE_SERVER			0x01

/** \def TCP_TYPE_CLIENT
 *	\brief TCP socket represents a client application
 *
 *	If TCP socket entry is of client type, application using it can
 *	establish connection through it towards other Internet hosts but
 *	can not accept any incoming connections on the port (execute
 *	tcp_listen() on it that is).
 */
#define	TCP_TYPE_CLIENT			0x02

/** \def TCP_TYPE_CLIENT_SERVER
 *	\brief	TCP socket can act as client or as server
 *
 *	If TCP socket entry is of this type, application using it can 
 *	both listen on a given socket or establish connection towards an
 *	outside host.
 */
#define	TCP_TYPE_CLIENT_SERVER	0x03

/* TCP States. For more detailed descriptions see RFC793		*/

#define	TCP_STATE_FREE			1	/**< Entry is free and unused 				*/
#define	TCP_STATE_RESERVED		2	/**< Entry is reserved for use				*/
#define	TCP_STATE_CLOSED		3	/**< Entry allocated, socket still closed	*/
#define TCP_STATE_LISTENING		4	/**< Socket in listening state,
									 *	 waiting for incoming connections
									 */
#define TCP_STATE_SYN_RECEIVED	5	/**< SYN packet received (either first
									 *	 SYN packet or response to SYN that
									 *	 we have previously sent)
									 */
#define	TCP_STATE_SYN_SENT		6	/**< SYN packet sent as an attempt
									 *	 to establish a connection
									 */
#define TCP_STATE_FINW1			7	/**< User issued tcp_close request
									 *	 issued so FIN packet was sent
									 */
#define	TCP_STATE_FINW2			8	/**< Received ACK of our FIN, now
									 *	 waiting for other side to send
									 *	 FIN
									 */
#define TCP_STATE_CLOSING		9	/**< Received FIN independently of 
									 *	 our FIN
									 */
#define	TCP_STATE_LAST_ACK		10	/**< Waiting for last ACK packet as a 
									 *	 response to our FIN
									 */