Diff: uip/uip.h

Revision:

0:685224d2f66d

Child:

3:a2715e9c7737

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/uip/uip.h	Sat Jun 14 16:02:21 2014 +0000
@@ -0,0 +1,1601 @@
+
+/**
+ * \addtogroup uip
+ * @{
+ */
+
+/**
+ * \file
+ * Header file for the uIP TCP/IP stack.
+ * \author Adam Dunkels <adam@dunkels.com>
+ *
+ * The uIP TCP/IP stack header file contains definitions for a number
+ * of C macros that are used by uIP programs as well as internal uIP
+ * structures, TCP/IP header structures and function declarations.
+ *
+ */
+
+
+/*
+ * Copyright (c) 2001-2003, Adam Dunkels.
+ * 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 name of the author may not be used to endorse or promote
+ *    products derived from this software without specific prior
+ *    written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
+ * 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 THE AUTHOR 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.
+ *
+ * This file is part of the uIP TCP/IP stack.
+ *
+ * $Id: uip.h,v 1.40 2006/06/08 07:12:07 adam Exp $
+ *
+ */
+
+#ifndef __UIP_H__
+#define __UIP_H__
+
+#include "uipopt.h"
+
+/**
+ * Repressentation of an IP address.
+ *
+ */
+typedef u16_t uip_ip4addr_t[2];
+typedef u16_t uip_ip6addr_t[8];
+#if UIP_CONF_IPV6
+typedef uip_ip6addr_t uip_ipaddr_t;
+#else /* UIP_CONF_IPV6 */
+typedef uip_ip4addr_t uip_ipaddr_t;
+#endif /* UIP_CONF_IPV6 */
+
+/*---------------------------------------------------------------------------*/
+/* First, the functions that should be called from the
+ * system. Initialization, the periodic timer and incoming packets are
+ * handled by the following three functions.
+ */
+
+/**
+ * \defgroup uipconffunc uIP configuration functions
+ * @{
+ *
+ * The uIP configuration functions are used for setting run-time
+ * parameters in uIP such as IP addresses.
+ */
+
+/**
+ * Set the IP address of this host.
+ *
+ * The IP address is represented as a 4-byte array where the first
+ * octet of the IP address is put in the first member of the 4-byte
+ * array.
+ *
+ * Example:
+ \code
+
+ uip_ipaddr_t addr;
+
+ uip_ipaddr(&addr, 192,168,1,2);
+ uip_sethostaddr(&addr);
+ 
+ \endcode
+ * \param addr A pointer to an IP address of type uip_ipaddr_t;
+ *
+ * \sa uip_ipaddr()
+ *
+ * \hideinitializer
+ */
+#define uip_sethostaddr(addr) uip_ipaddr_copy(uip_hostaddr, (addr))
+
+/**
+ * Get the IP address of this host.
+ *
+ * The IP address is represented as a 4-byte array where the first
+ * octet of the IP address is put in the first member of the 4-byte
+ * array.
+ *
+ * Example:
+ \code
+ uip_ipaddr_t hostaddr;
+
+ uip_gethostaddr(&hostaddr);
+ \endcode
+ * \param addr A pointer to a uip_ipaddr_t variable that will be
+ * filled in with the currently configured IP address.
+ *
+ * \hideinitializer
+ */
+#define uip_gethostaddr(addr) uip_ipaddr_copy((addr), uip_hostaddr)
+
+/**
+ * Set the default router's IP address.
+ *
+ * \param addr A pointer to a uip_ipaddr_t variable containing the IP
+ * address of the default router.
+ *
+ * \sa uip_ipaddr()
+ *
+ * \hideinitializer
+ */
+#define uip_setdraddr(addr) uip_ipaddr_copy(uip_draddr, (addr))
+
+/**
+ * Set the netmask.
+ *
+ * \param addr A pointer to a uip_ipaddr_t variable containing the IP
+ * address of the netmask.
+ *
+ * \sa uip_ipaddr()
+ *
+ * \hideinitializer
+ */
+#define uip_setnetmask(addr) uip_ipaddr_copy(uip_netmask, (addr))
+
+
+/**
+ * Get the default router's IP address.
+ *
+ * \param addr A pointer to a uip_ipaddr_t variable that will be
+ * filled in with the IP address of the default router.
+ *
+ * \hideinitializer
+ */
+#define uip_getdraddr(addr) uip_ipaddr_copy((addr), uip_draddr)
+
+/**
+ * Get the netmask.
+ *
+ * \param addr A pointer to a uip_ipaddr_t variable that will be
+ * filled in with the value of the netmask.
+ *
+ * \hideinitializer
+ */
+#define uip_getnetmask(addr) uip_ipaddr_copy((addr), uip_netmask)
+
+/** @} */
+
+/**
+ * \defgroup uipinit uIP initialization functions
+ * @{
+ *
+ * The uIP initialization functions are used for booting uIP.
+ */
+
+/**
+ * uIP initialization function.
+ *
+ * This function should be called at boot up to initilize the uIP
+ * TCP/IP stack.
+ */
+void uip_init(void);
+
+/**
+ * uIP initialization function.
+ *
+ * This function may be used at boot time to set the initial ip_id.
+ */
+void uip_setipid(u16_t id);
+
+/** @} */
+
+/**
+ * \defgroup uipdevfunc uIP device driver functions
+ * @{
+ *
+ * These functions are used by a network device driver for interacting
+ * with uIP.
+ */
+
+/**
+ * Process an incoming packet.
+ *
+ * This function should be called when the device driver has received
+ * a packet from the network. The packet from the device driver must
+ * be present in the uip_buf buffer, and the length of the packet
+ * should be placed in the uip_len variable.
+ *
+ * When the function returns, there may be an outbound packet placed
+ * in the uip_buf packet buffer. If so, the uip_len variable is set to
+ * the length of the packet. If no packet is to be sent out, the
+ * uip_len variable is set to 0.
+ *
+ * The usual way of calling the function is presented by the source
+ * code below.
+ \code
+  uip_len = devicedriver_poll();
+  if(uip_len > 0) {
+    uip_input();
+    if(uip_len > 0) {
+      devicedriver_send();
+    }
+  }
+ \endcode
+ *
+ * \note If you are writing a uIP device driver that needs ARP
+ * (Address Resolution Protocol), e.g., when running uIP over
+ * Ethernet, you will need to call the uIP ARP code before calling
+ * this function:
+ \code
+  #define BUF ((struct uip_eth_hdr *)&uip_buf[0])
+  uip_len = ethernet_devicedrver_poll();
+  if(uip_len > 0) {
+    if(BUF->type == HTONS(UIP_ETHTYPE_IP)) {
+      uip_arp_ipin();
+      uip_input();
+      if(uip_len > 0) {
+        uip_arp_out();
+	ethernet_devicedriver_send();
+      }
+    } else if(BUF->type == HTONS(UIP_ETHTYPE_ARP)) {
+      uip_arp_arpin();
+      if(uip_len > 0) {
+	ethernet_devicedriver_send();
+      }
+    }
+ \endcode
+ *
+ * \hideinitializer
+ */
+#define uip_input()        uip_process(UIP_DATA)
+
+/**
+ * Periodic processing for a connection identified by its number.
+ *
+ * This function does the necessary periodic processing (timers,
+ * polling) for a uIP TCP conneciton, and should be called when the
+ * periodic uIP timer goes off. It should be called for every
+ * connection, regardless of whether they are open of closed.
+ *
+ * When the function returns, it may have an outbound packet waiting
+ * for service in the uIP packet buffer, and if so the uip_len
+ * variable is set to a value larger than zero. The device driver
+ * should be called to send out the packet.
+ *
+ * The ususal way of calling the function is through a for() loop like
+ * this:
+ \code
+  for(i = 0; i < UIP_CONNS; ++i) {
+    uip_periodic(i);
+    if(uip_len > 0) {
+      devicedriver_send();
+    }
+  }
+ \endcode
+ *
+ * \note If you are writing a uIP device driver that needs ARP
+ * (Address Resolution Protocol), e.g., when running uIP over
+ * Ethernet, you will need to call the uip_arp_out() function before
+ * calling the device driver:
+ \code
+  for(i = 0; i < UIP_CONNS; ++i) {
+    uip_periodic(i);
+    if(uip_len > 0) {
+      uip_arp_out();
+      ethernet_devicedriver_send();
+    }
+  }
+ \endcode
+ *
+ * \param conn The number of the connection which is to be periodically polled.
+ *
+ * \hideinitializer
+ */
+#define uip_periodic(conn) do { uip_conn = &uip_conns[conn]; \
+                                uip_process(UIP_TIMER); } while (0)
+
+/**
+ *
+ *
+ */
+#define uip_conn_active(conn) (uip_conns[conn].tcpstateflags != UIP_CLOSED)
+
+/**
+ * Perform periodic processing for a connection identified by a pointer
+ * to its structure.
+ *
+ * Same as uip_periodic() but takes a pointer to the actual uip_conn
+ * struct instead of an integer as its argument. This function can be
+ * used to force periodic processing of a specific connection.
+ *
+ * \param conn A pointer to the uip_conn struct for the connection to
+ * be processed.
+ *
+ * \hideinitializer
+ */
+#define uip_periodic_conn(conn) do { uip_conn = conn; \
+                                     uip_process(UIP_TIMER); } while (0)
+
+/**
+ * Reuqest that a particular connection should be polled.
+ *
+ * Similar to uip_periodic_conn() but does not perform any timer
+ * processing. The application is polled for new data.
+ *
+ * \param conn A pointer to the uip_conn struct for the connection to
+ * be processed.
+ *
+ * \hideinitializer
+ */
+#define uip_poll_conn(conn) do { uip_conn = conn; \
+                                 uip_process(UIP_POLL_REQUEST); } while (0)
+
+
+#if UIP_UDP
+/**
+ * Periodic processing for a UDP connection identified by its number.
+ *
+ * This function is essentially the same as uip_periodic(), but for
+ * UDP connections. It is called in a similar fashion as the
+ * uip_periodic() function:
+ \code
+  for(i = 0; i < UIP_UDP_CONNS; i++) {
+    uip_udp_periodic(i);
+    if(uip_len > 0) {
+      devicedriver_send();
+    }
+  }
+ \endcode
+ *
+ * \note As for the uip_periodic() function, special care has to be
+ * taken when using uIP together with ARP and Ethernet:
+ \code
+  for(i = 0; i < UIP_UDP_CONNS; i++) {
+    uip_udp_periodic(i);
+    if(uip_len > 0) {
+      uip_arp_out();
+      ethernet_devicedriver_send();
+    }
+  }
+ \endcode
+ *
+ * \param conn The number of the UDP connection to be processed.
+ *
+ * \hideinitializer
+ */
+#define uip_udp_periodic(conn) do { uip_udp_conn = &uip_udp_conns[conn]; \
+                                uip_process(UIP_UDP_TIMER); } while (0)
+
+/**
+ * Periodic processing for a UDP connection identified by a pointer to
+ * its structure.
+ *
+ * Same as uip_udp_periodic() but takes a pointer to the actual
+ * uip_conn struct instead of an integer as its argument. This
+ * function can be used to force periodic processing of a specific
+ * connection.
+ *
+ * \param conn A pointer to the uip_udp_conn struct for the connection
+ * to be processed.
+ *
+ * \hideinitializer
+ */
+#define uip_udp_periodic_conn(conn) do { uip_udp_conn = conn; \
+                                         uip_process(UIP_UDP_TIMER); } while (0)
+
+
+#endif /* UIP_UDP */
+
+/**
+ * The uIP packet buffer.
+ *
+ * The uip_buf array is used to hold incoming and outgoing
+ * packets. The device driver should place incoming data into this
+ * buffer. When sending data, the device driver should read the link
+ * level headers and the TCP/IP headers from this buffer. The size of
+ * the link level headers is configured by the UIP_LLH_LEN define.
+ *
+ * \note The application data need not be placed in this buffer, so
+ * the device driver must read it from the place pointed to by the
+ * uip_appdata pointer as illustrated by the following example:
+ \code
+ void
+ devicedriver_send(void)
+ {
+    hwsend(&uip_buf[0], UIP_LLH_LEN);
+    if(uip_len <= UIP_LLH_LEN + UIP_TCPIP_HLEN) {
+      hwsend(&uip_buf[UIP_LLH_LEN], uip_len - UIP_LLH_LEN);
+    } else {
+      hwsend(&uip_buf[UIP_LLH_LEN], UIP_TCPIP_HLEN);
+      hwsend(uip_appdata, uip_len - UIP_TCPIP_HLEN - UIP_LLH_LEN);
+    }
+ }
+ \endcode
+ */
+extern u8_t uip_buf[UIP_BUFSIZE+2];
+
+/** @} */
+
+/*---------------------------------------------------------------------------*/
+/* Functions that are used by the uIP application program. Opening and
+ * closing connections, sending and receiving data, etc. is all
+ * handled by the functions below.
+*/
+/**
+ * \defgroup uipappfunc uIP application functions
+ * @{
+ *
+ * Functions used by an application running of top of uIP.
+ */
+
+/**
+ * Start listening to the specified port.
+ *
+ * \note Since this function expects the port number in network byte
+ * order, a conversion using HTONS() or htons() is necessary.
+ *
+ \code
+ uip_listen(HTONS(80));
+ \endcode
+ *
+ * \param port A 16-bit port number in network byte order.
+ */
+void uip_listen(u16_t port);
+
+/**
+ * Stop listening to the specified port.
+ *
+ * \note Since this function expects the port number in network byte
+ * order, a conversion using HTONS() or htons() is necessary.
+ *
+ \code
+ uip_unlisten(HTONS(80));
+ \endcode
+ *
+ * \param port A 16-bit port number in network byte order.
+ */
+void uip_unlisten(u16_t port);
+
+/**
+ * Connect to a remote host using TCP.
+ *
+ * This function is used to start a new connection to the specified
+ * port on the specied host. It allocates a new connection identifier,
+ * sets the connection to the SYN_SENT state and sets the
+ * retransmission timer to 0. This will cause a TCP SYN segment to be
+ * sent out the next time this connection is periodically processed,
+ * which usually is done within 0.5 seconds after the call to
+ * uip_connect().
+ *
+ * \note This function is avaliable only if support for active open
+ * has been configured by defining UIP_ACTIVE_OPEN to 1 in uipopt.h.
+ *
+ * \note Since this function requires the port number to be in network
+ * byte order, a conversion using HTONS() or htons() is necessary.
+ *
+ \code
+ uip_ipaddr_t ipaddr;
+
+ uip_ipaddr(&ipaddr, 192,168,1,2);
+ uip_connect(&ipaddr, HTONS(80));
+ \endcode
+ *
+ * \param ripaddr The IP address of the remote hot.
+ *
+ * \param port A 16-bit port number in network byte order.
+ *
+ * \return A pointer to the uIP connection identifier for the new connection,
+ * or NULL if no connection could be allocated.
+ *
+ */
+struct uip_conn *uip_connect(uip_ipaddr_t *ripaddr, u16_t port);
+
+
+
+/**
+ * \internal
+ *
+ * Check if a connection has outstanding (i.e., unacknowledged) data.
+ *
+ * \param conn A pointer to the uip_conn structure for the connection.
+ *
+ * \hideinitializer
+ */
+#define uip_outstanding(conn) ((conn)->len)
+
+/**
+ * Send data on the current connection.
+ *
+ * This function is used to send out a single segment of TCP
+ * data. Only applications that have been invoked by uIP for event
+ * processing can send data.
+ *
+ * The amount of data that actually is sent out after a call to this
+ * funcion is determined by the maximum amount of data TCP allows. uIP
+ * will automatically crop the data so that only the appropriate
+ * amount of data is sent. The function uip_mss() can be used to query
+ * uIP for the amount of data that actually will be sent.
+ *
+ * \note This function does not guarantee that the sent data will
+ * arrive at the destination. If the data is lost in the network, the
+ * application will be invoked with the uip_rexmit() event being
+ * set. The application will then have to resend the data using this
+ * function.
+ *
+ * \param data A pointer to the data which is to be sent.
+ *
+ * \param len The maximum amount of data bytes to be sent.
+ *
+ * \hideinitializer
+ */
+void uip_send(const void *data, int len);
+
+/**
+ * The length of any incoming data that is currently avaliable (if avaliable)
+ * in the uip_appdata buffer.
+ *
+ * The test function uip_data() must first be used to check if there
+ * is any data available at all.
+ *
+ * \hideinitializer
+ */
+/*void uip_datalen(void);*/
+#define uip_datalen()       uip_len
+
+/**
+ * The length of any out-of-band data (urgent data) that has arrived
+ * on the connection.
+ *
+ * \note The configuration parameter UIP_URGDATA must be set for this
+ * function to be enabled.
+ *
+ * \hideinitializer
+ */
+#define uip_urgdatalen()    uip_urglen
+
+/**
+ * Close the current connection.
+ *
+ * This function will close the current connection in a nice way.
+ *
+ * \hideinitializer
+ */
+#define uip_close()         (uip_flags = UIP_CLOSE)
+
+/**
+ * Abort the current connection.
+ *
+ * This function will abort (reset) the current connection, and is
+ * usually used when an error has occured that prevents using the
+ * uip_close() function.
+ *
+ * \hideinitializer
+ */
+#define uip_abort()         (uip_flags = UIP_ABORT)
+
+/**
+ * Tell the sending host to stop sending data.
+ *
+ * This function will close our receiver's window so that we stop
+ * receiving data for the current connection.
+ *
+ * \hideinitializer
+ */
+#define uip_stop()          (uip_conn->tcpstateflags |= UIP_STOPPED)
+
+/**
+ * Find out if the current connection has been previously stopped with
+ * uip_stop().
+ *
+ * \hideinitializer
+ */
+#define uip_stopped(conn)   ((conn)->tcpstateflags & UIP_STOPPED)
+
+/**
+ * Restart the current connection, if is has previously been stopped
+ * with uip_stop().
+ *
+ * This function will open the receiver's window again so that we
+ * start receiving data for the current connection.
+ *
+ * \hideinitializer
+ */
+#define uip_restart()         do { uip_flags |= UIP_NEWDATA; \
+                                   uip_conn->tcpstateflags &= ~UIP_STOPPED; \
+                              } while(0)
+
+
+/* uIP tests that can be made to determine in what state the current
+   connection is, and what the application function should do. */
+
+/**
+ * Is the current connection a UDP connection?
+ *
+ * This function checks whether the current connection is a UDP connection.
+ *
+ * \hideinitializer
+ *
+ */
+#define uip_udpconnection() (uip_conn == NULL)
+
+/**
+ * Is new incoming data available?
+ *
+ * Will reduce to non-zero if there is new data for the application
+ * present at the uip_appdata pointer. The size of the data is
+ * avaliable through the uip_len variable.
+ *
+ * \hideinitializer
+ */
+#define uip_newdata()   (uip_flags & UIP_NEWDATA)
+
+/**
+ * Has previously sent data been acknowledged?
+ *
+ * Will reduce to non-zero if the previously sent data has been
+ * acknowledged by the remote host. This means that the application
+ * can send new data.
+ *
+ * \hideinitializer
+ */
+#define uip_acked()   (uip_flags & UIP_ACKDATA)
+
+/**
+ * Has the connection just been connected?
+ *
+ * Reduces to non-zero if the current connection has been connected to
+ * a remote host. This will happen both if the connection has been
+ * actively opened (with uip_connect()) or passively opened (with
+ * uip_listen()).
+ *
+ * \hideinitializer
+ */
+#define uip_connected() (uip_flags & UIP_CONNECTED)
+
+/**
+ * Has the connection been closed by the other end?
+ *
+ * Is non-zero if the connection has been closed by the remote
+ * host. The application may then do the necessary clean-ups.
+ *
+ * \hideinitializer
+ */
+#define uip_closed()    (uip_flags & UIP_CLOSE)
+
+/**
+ * Has the connection been aborted by the other end?
+ *
+ * Non-zero if the current connection has been aborted (reset) by the
+ * remote host.
+ *
+ * \hideinitializer
+ */
+#define uip_aborted()    (uip_flags & UIP_ABORT)
+
+/**
+ * Has the connection timed out?
+ *
+ * Non-zero if the current connection has been aborted due to too many
+ * retransmissions.
+ *
+ * \hideinitializer
+ */
+#define uip_timedout()    (uip_flags & UIP_TIMEDOUT)
+
+/**
+ * Do we need to retransmit previously data?
+ *
+ * Reduces to non-zero if the previously sent data has been lost in
+ * the network, and the application should retransmit it. The
+ * application should send the exact same data as it did the last
+ * time, using the uip_send() function.
+ *
+ * \hideinitializer
+ */
+#define uip_rexmit()     (uip_flags & UIP_REXMIT)
+
+/**
+ * Is the connection being polled by uIP?
+ *
+ * Is non-zero if the reason the application is invoked is that the
+ * current connection has been idle for a while and should be
+ * polled.
+ *
+ * The polling event can be used for sending data without having to
+ * wait for the remote host to send data.
+ *
+ * \hideinitializer
+ */
+#define uip_poll()       (uip_flags & UIP_POLL)
+
+/**
+ * Get the initial maxium segment size (MSS) of the current
+ * connection.
+ *
+ * \hideinitializer
+ */
+#define uip_initialmss()             (uip_conn->initialmss)
+
+/**
+ * Get the current maxium segment size that can be sent on the current
+ * connection.
+ *
+ * The current maxiumum segment size that can be sent on the
+ * connection is computed from the receiver's window and the MSS of
+ * the connection (which also is available by calling
+ * uip_initialmss()).
+ *
+ * \hideinitializer
+ */
+#define uip_mss()             (uip_conn->mss)
+
+/**
+ * Set up a new UDP connection.
+ *
+ * This function sets up a new UDP connection. The function will
+ * automatically allocate an unused local port for the new
+ * connection. However, another port can be chosen by using the
+ * uip_udp_bind() call, after the uip_udp_new() function has been
+ * called.
+ *
+ * Example:
+ \code
+ uip_ipaddr_t addr;
+ struct uip_udp_conn *c;
+ 
+ uip_ipaddr(&addr, 192,168,2,1);
+ c = uip_udp_new(&addr, HTONS(12345));
+ if(c != NULL) {
+   uip_udp_bind(c, HTONS(12344));
+ }
+ \endcode
+ * \param ripaddr The IP address of the remote host.
+ *
+ * \param rport The remote port number in network byte order.
+ *
+ * \return The uip_udp_conn structure for the new connection or NULL
+ * if no connection could be allocated.
+ */
+struct uip_udp_conn *uip_udp_new(uip_ipaddr_t *ripaddr, u16_t rport);
+
+/**
+ * Removed a UDP connection.
+ *
+ * \param conn A pointer to the uip_udp_conn structure for the connection.
+ *
+ * \hideinitializer
+ */
+#define uip_udp_remove(conn) (conn)->lport = 0
+
+/**
+ * Bind a UDP connection to a local port.
+ *
+ * \param conn A pointer to the uip_udp_conn structure for the
+ * connection.
+ *
+ * \param port The local port number, in network byte order.
+ *
+ * \hideinitializer
+ */
+#define uip_udp_bind(conn, port) (conn)->lport = port
+
+/**
+ * Send a UDP datagram of length len on the current connection.
+ *
+ * This function can only be called in response to a UDP event (poll
+ * or newdata). The data must be present in the uip_buf buffer, at the
+ * place pointed to by the uip_appdata pointer.
+ *
+ * \param len The length of the data in the uip_buf buffer.
+ *
+ * \hideinitializer
+ */
+#define uip_udp_send(len) uip_send((char *)uip_appdata, len)
+
+/** @} */
+
+/* uIP convenience and converting functions. */
+
+/**
+ * \defgroup uipconvfunc uIP conversion functions
+ * @{
+ *
+ * These functions can be used for converting between different data
+ * formats used by uIP.
+ */
+ 
+/**
+ * Construct an IP address from four bytes.
+ *
+ * This function constructs an IP address of the type that uIP handles
+ * internally from four bytes. The function is handy for specifying IP
+ * addresses to use with e.g. the uip_connect() function.
+ *
+ * Example:
+ \code
+ uip_ipaddr_t ipaddr;
+ struct uip_conn *c;
+ 
+ uip_ipaddr(&ipaddr, 192,168,1,2);
+ c = uip_connect(&ipaddr, HTONS(80));
+ \endcode
+ *
+ * \param addr A pointer to a uip_ipaddr_t variable that will be
+ * filled in with the IP address.
+ *
+ * \param addr0 The first octet of the IP address.
+ * \param addr1 The second octet of the IP address.
+ * \param addr2 The third octet of the IP address.
+ * \param addr3 The forth octet of the IP address.
+ *
+ * \hideinitializer
+ */
+#define uip_ipaddr(addr, addr0,addr1,addr2,addr3) do { \
+                     ((u16_t *)(addr))[0] = HTONS(((addr0) << 8) | (addr1)); \
+                     ((u16_t *)(addr))[1] = HTONS(((addr2) << 8) | (addr3)); \
+                  } while(0)
+
+/**
+ * Construct an IPv6 address from eight 16-bit words.
+ *
+ * This function constructs an IPv6 address.
+ *
+ * \hideinitializer
+ */
+#define uip_ip6addr(addr, addr0,addr1,addr2,addr3,addr4,addr5,addr6,addr7) do { \
+                     ((u16_t *)(addr))[0] = HTONS((addr0)); \
+                     ((u16_t *)(addr))[1] = HTONS((addr1)); \
+                     ((u16_t *)(addr))[2] = HTONS((addr2)); \
+                     ((u16_t *)(addr))[3] = HTONS((addr3)); \
+                     ((u16_t *)(addr))[4] = HTONS((addr4)); \
+                     ((u16_t *)(addr))[5] = HTONS((addr5)); \
+                     ((u16_t *)(addr))[6] = HTONS((addr6)); \
+                     ((u16_t *)(addr))[7] = HTONS((addr7)); \
+                  } while(0)
+
+/**
+ * Copy an IP address to another IP address.
+ *
+ * Copies an IP address from one place to another.
+ *
+ * Example:
+ \code
+ uip_ipaddr_t ipaddr1, ipaddr2;
+
+ uip_ipaddr(&ipaddr1, 192,16,1,2);
+ uip_ipaddr_copy(&ipaddr2, &ipaddr1);
+ \endcode
+ *
+ * \param dest The destination for the copy.
+ * \param src The source from where to copy.
+ *
+ * \hideinitializer
+ */
+#if !UIP_CONF_IPV6
+#define uip_ipaddr_copy(dest, src) do { \
+                     ((u16_t *)dest)[0] = ((u16_t *)src)[0]; \
+                     ((u16_t *)dest)[1] = ((u16_t *)src)[1]; \
+                  } while(0)
+#else /* !UIP_CONF_IPV6 */
+#define uip_ipaddr_copy(dest, src) memcpy(dest, src, sizeof(uip_ip6addr_t))
+#endif /* !UIP_CONF_IPV6 */
+
+/**
+ * Compare two IP addresses
+ *
+ * Compares two IP addresses.
+ *
+ * Example:
+ \code
+ uip_ipaddr_t ipaddr1, ipaddr2;
+
+ uip_ipaddr(&ipaddr1, 192,16,1,2);
+ if(uip_ipaddr_cmp(&ipaddr2, &ipaddr1)) {
+    printf("They are the same");
+ }
+ \endcode
+ *
+ * \param addr1 The first IP address.
+ * \param addr2 The second IP address.
+ *
+ * \hideinitializer
+ */
+#if !UIP_CONF_IPV6
+#define uip_ipaddr_cmp(addr1, addr2) (((u16_t *)addr1)[0] == ((u16_t *)addr2)[0] && \
+				      ((u16_t *)addr1)[1] == ((u16_t *)addr2)[1])
+#else /* !UIP_CONF_IPV6 */
+#define uip_ipaddr_cmp(addr1, addr2) (memcmp(addr1, addr2, sizeof(uip_ip6addr_t)) == 0)
+#endif /* !UIP_CONF_IPV6 */
+
+/**
+ * Compare two IP addresses with netmasks
+ *
+ * Compares two IP addresses with netmasks. The masks are used to mask
+ * out the bits that are to be compared.
+ *
+ * Example:
+ \code
+ uip_ipaddr_t ipaddr1, ipaddr2, mask;
+
+ uip_ipaddr(&mask, 255,255,255,0);
+ uip_ipaddr(&ipaddr1, 192,16,1,2);
+ uip_ipaddr(&ipaddr2, 192,16,1,3);
+ if(uip_ipaddr_maskcmp(&ipaddr1, &ipaddr2, &mask)) {
+    printf("They are the same");
+ }
+ \endcode
+ *
+ * \param addr1 The first IP address.
+ * \param addr2 The second IP address.
+ * \param mask The netmask.
+ *
+ * \hideinitializer
+ */
+#define uip_ipaddr_maskcmp(addr1, addr2, mask) \
+                          (((((u16_t *)addr1)[0] & ((u16_t *)mask)[0]) == \
+                            (((u16_t *)addr2)[0] & ((u16_t *)mask)[0])) && \
+                           ((((u16_t *)addr1)[1] & ((u16_t *)mask)[1]) == \
+                            (((u16_t *)addr2)[1] & ((u16_t *)mask)[1])))
+
+
+/**
+ * Mask out the network part of an IP address.
+ *
+ * Masks out the network part of an IP address, given the address and
+ * the netmask.
+ *
+ * Example:
+ \code
+ uip_ipaddr_t ipaddr1, ipaddr2, netmask;
+
+ uip_ipaddr(&ipaddr1, 192,16,1,2);
+ uip_ipaddr(&netmask, 255,255,255,0);
+ uip_ipaddr_mask(&ipaddr2, &ipaddr1, &netmask);
+ \endcode
+ *
+ * In the example above, the variable "ipaddr2" will contain the IP
+ * address 192.168.1.0.
+ *
+ * \param dest Where the result is to be placed.
+ * \param src The IP address.
+ * \param mask The netmask.
+ *
+ * \hideinitializer
+ */
+#define uip_ipaddr_mask(dest, src, mask) do { \
+                     ((u16_t *)dest)[0] = ((u16_t *)src)[0] & ((u16_t *)mask)[0]; \
+                     ((u16_t *)dest)[1] = ((u16_t *)src)[1] & ((u16_t *)mask)[1]; \
+                  } while(0)
+
+/**
+ * Pick the first octet of an IP address.
+ *
+ * Picks out the first octet of an IP address.
+ *
+ * Example:
+ \code
+ uip_ipaddr_t ipaddr;
+ u8_t octet;
+
+ uip_ipaddr(&ipaddr, 1,2,3,4);
+ octet = uip_ipaddr1(&ipaddr);
+ \endcode
+ *
+ * In the example above, the variable "octet" will contain the value 1.
+ *
+ * \hideinitializer
+ */
+#define uip_ipaddr1(addr) (htons(((u16_t *)(addr))[0]) >> 8)
+
+/**
+ * Pick the second octet of an IP address.
+ *
+ * Picks out the second octet of an IP address.
+ *
+ * Example:
+ \code
+ uip_ipaddr_t ipaddr;
+ u8_t octet;
+
+ uip_ipaddr(&ipaddr, 1,2,3,4);
+ octet = uip_ipaddr2(&ipaddr);
+ \endcode
+ *
+ * In the example above, the variable "octet" will contain the value 2.
+ *
+ * \hideinitializer
+ */
+#define uip_ipaddr2(addr) (htons(((u16_t *)(addr))[0]) & 0xff)
+
+/**
+ * Pick the third octet of an IP address.
+ *
+ * Picks out the third octet of an IP address.
+ *
+ * Example:
+ \code
+ uip_ipaddr_t ipaddr;
+ u8_t octet;
+
+ uip_ipaddr(&ipaddr, 1,2,3,4);
+ octet = uip_ipaddr3(&ipaddr);
+ \endcode
+ *
+ * In the example above, the variable "octet" will contain the value 3.
+ *
+ * \hideinitializer
+ */
+#define uip_ipaddr3(addr) (htons(((u16_t *)(addr))[1]) >> 8)
+
+/**
+ * Pick the fourth octet of an IP address.
+ *
+ * Picks out the fourth octet of an IP address.
+ *
+ * Example:
+ \code
+ uip_ipaddr_t ipaddr;
+ u8_t octet;
+
+ uip_ipaddr(&ipaddr, 1,2,3,4);
+ octet = uip_ipaddr4(&ipaddr);
+ \endcode
+ *
+ * In the example above, the variable "octet" will contain the value 4.
+ *
+ * \hideinitializer
+ */
+#define uip_ipaddr4(addr) (htons(((u16_t *)(addr))[1]) & 0xff)
+
+/**
+ * Convert 16-bit quantity from host byte order to network byte order.
+ *
+ * This macro is primarily used for converting constants from host
+ * byte order to network byte order. For converting variables to
+ * network byte order, use the htons() function instead.
+ *
+ * \hideinitializer
+ */
+#ifndef HTONS
+#   if UIP_BYTE_ORDER == UIP_BIG_ENDIAN
+#      define HTONS(n) (n)
+#   else /* UIP_BYTE_ORDER == UIP_BIG_ENDIAN */
+#      define HTONS(n) (u16_t)((((u16_t) (n)) << 8) | (((u16_t) (n)) >> 8))
+#   endif /* UIP_BYTE_ORDER == UIP_BIG_ENDIAN */
+#else
+#error "HTONS already defined!"
+#endif /* HTONS */
+
+/**
+ * Convert 16-bit quantity from host byte order to network byte order.
+ *
+ * This function is primarily used for converting variables from host
+ * byte order to network byte order. For converting constants to
+ * network byte order, use the HTONS() macro instead.
+ */
+#ifndef htons
+u16_t htons(u16_t val);
+#endif /* htons */
+#ifndef ntohs
+#define ntohs htons
+#endif
+
+/** @} */
+
+/**
+ * Pointer to the application data in the packet buffer.
+ *
+ * This pointer points to the application data when the application is
+ * called. If the application wishes to send data, the application may
+ * use this space to write the data into before calling uip_send().
+ */
+extern void *uip_appdata;
+
+#if UIP_URGDATA > 0
+/* u8_t *uip_urgdata:
+ *
+ * This pointer points to any urgent data that has been received. Only
+ * present if compiled with support for urgent data (UIP_URGDATA).
+ */
+extern void *uip_urgdata;
+#endif /* UIP_URGDATA > 0 */
+
+
+/**
+ * \defgroup uipdrivervars Variables used in uIP device drivers
+ * @{
+ *
+ * uIP has a few global variables that are used in device drivers for
+ * uIP.
+ */
+
+/**
+ * The length of the packet in the uip_buf buffer.
+ *
+ * The global variable uip_len holds the length of the packet in the
+ * uip_buf buffer.
+ *
+ * When the network device driver calls the uIP input function,
+ * uip_len should be set to the length of the packet in the uip_buf
+ * buffer.
+ *
+ * When sending packets, the device driver should use the contents of
+ * the uip_len variable to determine the length of the outgoing
+ * packet.
+ *
+ */
+extern u16_t uip_len;
+
+/** @} */
+
+#if UIP_URGDATA > 0
+extern u16_t uip_urglen, uip_surglen;
+#endif /* UIP_URGDATA > 0 */
+
+
+/**
+ * Representation of a uIP TCP connection.
+ *
+ * The uip_conn structure is used for identifying a connection. All
+ * but one field in the structure are to be considered read-only by an
+ * application. The only exception is the appstate field whos purpose
+ * is to let the application store application-specific state (e.g.,
+ * file pointers) for the connection. The type of this field is
+ * configured in the "uipopt.h" header file.
+ */
+struct uip_conn {
+  uip_ipaddr_t ripaddr;   /**< The IP address of the remote host. */
+  
+  u16_t lport;        /**< The local TCP port, in network byte order. */
+  u16_t rport;        /**< The local remote TCP port, in network byte
+			 order. */
+  
+  u8_t rcv_nxt[4];    /**< The sequence number that we expect to
+			 receive next. */
+  u8_t snd_nxt[4];    /**< The sequence number that was last sent by
+                         us. */
+  u16_t len;          /**< Length of the data that was previously sent. */
+  u16_t mss;          /**< Current maximum segment size for the
+			 connection. */
+  u16_t initialmss;   /**< Initial maximum segment size for the
+			 connection. */
+  u8_t sa;            /**< Retransmission time-out calculation state
+			 variable. */
+  u8_t sv;            /**< Retransmission time-out calculation state
+			 variable. */
+  u8_t rto;           /**< Retransmission time-out. */
+  u8_t tcpstateflags; /**< TCP state and flags. */
+  u8_t timer;         /**< The retransmission timer. */
+  u8_t nrtx;          /**< The number of retransmissions for the last
+			 segment sent. */
+
+  /** The application state. */
+  uip_tcp_appstate_t appstate;
+};
+
+
+/**
+ * Pointer to the current TCP connection.
+ *
+ * The uip_conn pointer can be used to access the current TCP
+ * connection.
+ */
+extern struct uip_conn *uip_conn;
+/* The array containing all uIP connections. */
+extern struct uip_conn uip_conns[UIP_CONNS];
+/**
+ * \addtogroup uiparch
+ * @{
+ */
+
+/**
+ * 4-byte array used for the 32-bit sequence number calculations.
+ */
+extern u8_t uip_acc32[4];
+
+/** @} */
+
+
+#if UIP_UDP
+/**
+ * Representation of a uIP UDP connection.
+ */
+struct uip_udp_conn {
+  uip_ipaddr_t ripaddr;   /**< The IP address of the remote peer. */
+  u16_t lport;        /**< The local port number in network byte order. */
+  u16_t rport;        /**< The remote port number in network byte order. */
+  u8_t  ttl;          /**< Default time-to-live. */
+
+  /** The application state. */
+  uip_udp_appstate_t appstate;
+};
+
+/**
+ * The current UDP connection.
+ */
+extern struct uip_udp_conn *uip_udp_conn;
+extern struct uip_udp_conn uip_udp_conns[UIP_UDP_CONNS];
+#endif /* UIP_UDP */
+
+/**
+ * The structure holding the TCP/IP statistics that are gathered if
+ * UIP_STATISTICS is set to 1.
+ *
+ */
+struct uip_stats {
+  struct {
+    uip_stats_t drop;     /**< Number of dropped packets at the IP
+			     layer. */
+    uip_stats_t recv;     /**< Number of received packets at the IP
+			     layer. */
+    uip_stats_t sent;     /**< Number of sent packets at the IP
+			     layer. */
+    uip_stats_t vhlerr;   /**< Number of packets dropped due to wrong
+			     IP version or header length. */
+    uip_stats_t hblenerr; /**< Number of packets dropped due to wrong
+			     IP length, high byte. */
+    uip_stats_t lblenerr; /**< Number of packets dropped due to wrong
+			     IP length, low byte. */
+    uip_stats_t fragerr;  /**< Number of packets dropped since they
+			     were IP fragments. */
+    uip_stats_t chkerr;   /**< Number of packets dropped due to IP
+			     checksum errors. */
+    uip_stats_t protoerr; /**< Number of packets dropped since they
+			     were neither ICMP, UDP nor TCP. */
+  } ip;                   /**< IP statistics. */
+  struct {
+    uip_stats_t drop;     /**< Number of dropped ICMP packets. */
+    uip_stats_t recv;     /**< Number of received ICMP packets. */
+    uip_stats_t sent;     /**< Number of sent ICMP packets. */
+    uip_stats_t typeerr;  /**< Number of ICMP packets with a wrong
+			     type. */
+  } icmp;                 /**< ICMP statistics. */
+  struct {
+    uip_stats_t drop;     /**< Number of dropped TCP segments. */
+    uip_stats_t recv;     /**< Number of recived TCP segments. */
+    uip_stats_t sent;     /**< Number of sent TCP segments. */
+    uip_stats_t chkerr;   /**< Number of TCP segments with a bad
+			     checksum. */
+    uip_stats_t ackerr;   /**< Number of TCP segments with a bad ACK
+			     number. */
+    uip_stats_t rst;      /**< Number of recevied TCP RST (reset) segments. */
+    uip_stats_t rexmit;   /**< Number of retransmitted TCP segments. */
+    uip_stats_t syndrop;  /**< Number of dropped SYNs due to too few
+			     connections was avaliable. */
+    uip_stats_t synrst;   /**< Number of SYNs for closed ports,
+			     triggering a RST. */
+  } tcp;                  /**< TCP statistics. */
+#if UIP_UDP
+  struct {
+    uip_stats_t drop;     /**< Number of dropped UDP segments. */
+    uip_stats_t recv;     /**< Number of recived UDP segments. */
+    uip_stats_t sent;     /**< Number of sent UDP segments. */
+    uip_stats_t chkerr;   /**< Number of UDP segments with a bad
+			     checksum. */
+  } udp;                  /**< UDP statistics. */
+#endif /* UIP_UDP */
+};
+
+/**
+ * The uIP TCP/IP statistics.
+ *
+ * This is the variable in which the uIP TCP/IP statistics are gathered.
+ */
+extern struct uip_stats uip_stat;
+
+
+/*---------------------------------------------------------------------------*/
+/* All the stuff below this point is internal to uIP and should not be
+ * used directly by an application or by a device driver.
+ */
+/*---------------------------------------------------------------------------*/
+/* u8_t uip_flags:
+ *
+ * When the application is called, uip_flags will contain the flags
+ * that are defined in this file. Please read below for more
+ * infomation.
+ */
+extern u8_t uip_flags;
+
+/* The following flags may be set in the global variable uip_flags
+   before calling the application callback. The UIP_ACKDATA,
+   UIP_NEWDATA, and UIP_CLOSE flags may both be set at the same time,
+   whereas the others are mutualy exclusive. Note that these flags
+   should *NOT* be accessed directly, but only through the uIP
+   functions/macros. */
+
+#define UIP_ACKDATA   1     /* Signifies that the outstanding data was
+			       acked and the application should send
+			       out new data instead of retransmitting
+			       the last data. */
+#define UIP_NEWDATA   2     /* Flags the fact that the peer has sent
+			       us new data. */
+#define UIP_REXMIT    4     /* Tells the application to retransmit the
+			       data that was last sent. */
+#define UIP_POLL      8     /* Used for polling the application, to
+			       check if the application has data that
+			       it wants to send. */
+#define UIP_CLOSE     16    /* The remote host has closed the
+			       connection, thus the connection has
+			       gone away. Or the application signals
+			       that it wants to close the
+			       connection. */
+#define UIP_ABORT     32    /* The remote host has aborted the
+			       connection, thus the connection has
+			       gone away. Or the application signals
+			       that it wants to abort the
+			       connection. */
+#define UIP_CONNECTED 64    /* We have got a connection from a remote
+                               host and have set up a new connection
+                               for it, or an active connection has
+                               been successfully established. */
+
+#define UIP_TIMEDOUT  128   /* The connection has been aborted due to
+			       too many retransmissions. */
+
+/* uip_process(flag):
+ *
+ * The actual uIP function which does all the work.
+ */
+void uip_process(u8_t flag);
+
+/* The following flags are passed as an argument to the uip_process()
+   function. They are used to distinguish between the two cases where
+   uip_process() is called. It can be called either because we have
+   incoming data that should be processed, or because the periodic
+   timer has fired. These values are never used directly, but only in
+   the macrose defined in this file. */
+ 
+#define UIP_DATA          1     /* Tells uIP that there is incoming
+				   data in the uip_buf buffer. The
+				   length of the data is stored in the
+				   global variable uip_len. */
+#define UIP_TIMER         2     /* Tells uIP that the periodic timer
+				   has fired. */
+#define UIP_POLL_REQUEST  3     /* Tells uIP that a connection should
+				   be polled. */
+#define UIP_UDP_SEND_CONN 4     /* Tells uIP that a UDP datagram
+				   should be constructed in the
+				   uip_buf buffer. */
+#if UIP_UDP
+#define UIP_UDP_TIMER     5
+#endif /* UIP_UDP */
+
+/* The TCP states used in the uip_conn->tcpstateflags. */
+#define UIP_CLOSED      0
+#define UIP_SYN_RCVD    1
+#define UIP_SYN_SENT    2
+#define UIP_ESTABLISHED 3
+#define UIP_FIN_WAIT_1  4
+#define UIP_FIN_WAIT_2  5
+#define UIP_CLOSING     6
+#define UIP_TIME_WAIT   7
+#define UIP_LAST_ACK    8
+#define UIP_TS_MASK     15
+  
+#define UIP_STOPPED      16
+
+/* The TCP and IP headers. */
+struct uip_tcpip_hdr {
+#if UIP_CONF_IPV6
+  /* IPv6 header. */
+  u8_t vtc,
+    tcflow;
+  u16_t flow;
+  u8_t len[2];
+  u8_t proto, ttl;
+  uip_ip6addr_t srcipaddr, destipaddr;
+#else /* UIP_CONF_IPV6 */
+  /* IPv4 header. */
+  u8_t vhl,
+    tos,
+    len[2],
+    ipid[2],
+    ipoffset[2],
+    ttl,
+    proto;
+  u16_t ipchksum;
+  u16_t srcipaddr[2],
+    destipaddr[2];
+#endif /* UIP_CONF_IPV6 */
+  
+  /* TCP header. */
+  u16_t srcport,
+    destport;
+  u8_t seqno[4],
+    ackno[4],
+    tcpoffset,
+    flags,
+    wnd[2];
+  u16_t tcpchksum;
+  u8_t urgp[2];
+  u8_t optdata[4];
+};
+
+/* The ICMP and IP headers. */
+struct uip_icmpip_hdr {
+#if UIP_CONF_IPV6
+  /* IPv6 header. */
+  u8_t vtc,
+    tcf;
+  u16_t flow;
+  u8_t len[2];
+  u8_t proto, ttl;
+  uip_ip6addr_t srcipaddr, destipaddr;
+#else /* UIP_CONF_IPV6 */
+  /* IPv4 header. */
+  u8_t vhl,
+    tos,
+    len[2],
+    ipid[2],
+    ipoffset[2],
+    ttl,
+    proto;
+  u16_t ipchksum;
+  u16_t srcipaddr[2],
+    destipaddr[2];
+#endif /* UIP_CONF_IPV6 */
+  
+  /* ICMP (echo) header. */
+  u8_t type, icode;
+  u16_t icmpchksum;
+#if !UIP_CONF_IPV6
+  u16_t id, seqno;
+#else /* !UIP_CONF_IPV6 */
+  u8_t flags, reserved1, reserved2, reserved3;
+  u8_t icmp6data[16];
+  u8_t options[1];
+#endif /* !UIP_CONF_IPV6 */
+};
+
+
+/* The UDP and IP headers. */
+struct uip_udpip_hdr {
+#if UIP_CONF_IPV6
+  /* IPv6 header. */
+  u8_t vtc,
+    tcf;
+  u16_t flow;
+  u8_t len[2];
+  u8_t proto, ttl;
+  uip_ip6addr_t srcipaddr, destipaddr;
+#else /* UIP_CONF_IPV6 */
+  /* IP header. */
+  u8_t vhl,
+    tos,
+    len[2],
+    ipid[2],
+    ipoffset[2],
+    ttl,
+    proto;
+  u16_t ipchksum;
+  u16_t srcipaddr[2],
+    destipaddr[2];
+#endif /* UIP_CONF_IPV6 */
+  
+  /* UDP header. */
+  u16_t srcport,
+    destport;
+  u16_t udplen;
+  u16_t udpchksum;
+};
+
+
+
+/**
+ * The buffer size available for user data in the \ref uip_buf buffer.
+ *
+ * This macro holds the available size for user data in the \ref
+ * uip_buf buffer. The macro is intended to be used for checking
+ * bounds of available user data.
+ *
+ * Example:
+ \code
+ snprintf(uip_appdata, UIP_APPDATA_SIZE, "%u\n", i);
+ \endcode
+ *
+ * \hideinitializer
+ */
+#define UIP_APPDATA_SIZE (UIP_BUFSIZE - UIP_LLH_LEN - UIP_TCPIP_HLEN)
+
+
+#define UIP_PROTO_ICMP  1
+#define UIP_PROTO_TCP   6
+#define UIP_PROTO_UDP   17
+#define UIP_PROTO_ICMP6 58
+
+/* Header sizes. */
+#if UIP_CONF_IPV6
+#define UIP_IPH_LEN    40
+#else /* UIP_CONF_IPV6 */
+#define UIP_IPH_LEN    20    /* Size of IP header */
+#endif /* UIP_CONF_IPV6 */
+#define UIP_UDPH_LEN    8    /* Size of UDP header */
+#define UIP_TCPH_LEN   20    /* Size of TCP header */
+#define UIP_IPUDPH_LEN (UIP_UDPH_LEN + UIP_IPH_LEN)    /* Size of IP +
+							  UDP
+							  header */
+#define UIP_IPTCPH_LEN (UIP_TCPH_LEN + UIP_IPH_LEN)    /* Size of IP +
+							  TCP
+							  header */
+#define UIP_TCPIP_HLEN UIP_IPTCPH_LEN
+
+
+#if UIP_FIXEDADDR
+extern const uip_ipaddr_t uip_hostaddr, uip_netmask, uip_draddr;
+#else /* UIP_FIXEDADDR */
+extern uip_ipaddr_t uip_hostaddr, uip_netmask, uip_draddr;
+#endif /* UIP_FIXEDADDR */
+
+
+
+/**
+ * Representation of a 48-bit Ethernet address.
+ */
+struct uip_eth_addr {
+  u8_t addr[6];
+};
+
+/**
+ * Calculate the Internet checksum over a buffer.
+ *
+ * The Internet checksum is the one's complement of the one's
+ * complement sum of all 16-bit words in the buffer.
+ *
+ * See RFC1071.
+ *
+ * \param buf A pointer to the buffer over which the checksum is to be
+ * computed.
+ *
+ * \param len The length of the buffer over which the checksum is to
+ * be computed.
+ *
+ * \return The Internet checksum of the buffer.
+ */
+u16_t uip_chksum(u16_t *buf, u16_t len);
+
+/**
+ * Calculate the IP header checksum of the packet header in uip_buf.
+ *
+ * The IP header checksum is the Internet checksum of the 20 bytes of
+ * the IP header.
+ *
+ * \return The IP header checksum of the IP header in the uip_buf
+ * buffer.
+ */
+u16_t uip_ipchksum(void);
+
+/**
+ * Calculate the TCP checksum of the packet in uip_buf and uip_appdata.
+ *
+ * The TCP checksum is the Internet checksum of data contents of the
+ * TCP segment, and a pseudo-header as defined in RFC793.
+ *
+ * \return The TCP checksum of the TCP segment in uip_buf and pointed
+ * to by uip_appdata.
+ */
+u16_t uip_tcpchksum(void);
+
+/**
+ * Calculate the UDP checksum of the packet in uip_buf and uip_appdata.
+ *
+ * The UDP checksum is the Internet checksum of data contents of the
+ * UDP segment, and a pseudo-header as defined in RFC768.
+ *
+ * \return The UDP checksum of the UDP segment in uip_buf and pointed
+ * to by uip_appdata.
+ */
+u16_t uip_udpchksum(void);
+
+
+#endif /* __UIP_H__ */
+
+
+/** @} */