Add uip on HEAD; it's safe to build, since nothing links against it at the

moment.

4 files changed, 3252 insertions, 0 deletions

diff --git a/src/proto/uip/uip.c b/src/proto/uip/uip.c
new file mode 100644
index 00000000..43aee944
--- /dev/null
+++ b/src/proto/uip/uip.c
@@ -0,0 +1,1504 @@
+/**
+ * \addtogroup uip
+ * @{
+ */
+
+/**
+ * \file
+ * The uIP TCP/IP stack code.
+ * \author Adam Dunkels <adam@dunkels.com>
+ */
+
+/*
+ * 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.
+ *
+ * $Id$
+ *
+ */
+
+/*
+This is a small implementation of the IP and TCP protocols (as well as
+some basic ICMP stuff). The implementation couples the IP, TCP and the
+application layers very tightly. To keep the size of the compiled code
+down, this code also features heavy usage of the goto statement.
+
+The principle is that we have a small buffer, called the uip_buf, in
+which the device driver puts an incoming packet. The TCP/IP stack
+parses the headers in the packet, and calls upon the application. If
+the remote host has sent data to the application, this data is present
+in the uip_buf and the application read the data from there. It is up
+to the application to put this data into a byte stream if needed. The
+application will not be fed with data that is out of sequence.
+
+If the application whishes to send data to the peer, it should put its
+data into the uip_buf, 40 bytes from the start of the buffer. The
+TCP/IP stack will calculate the checksums, and fill in the necessary
+header fields and finally send the packet back to the peer.
+*/
+
+#include "uip.h"
+#include "uipopt.h"
+#include "uip_arch.h"
+
+/*-----------------------------------------------------------------------------------*/
+/* Variable definitions. */
+
+
+/* The IP address of this host. If it is defined to be fixed (by setting UIP_FIXEDADDR to 1 in uipopt.h), the address is set here. Otherwise, the address */
+#if UIP_FIXEDADDR > 0
+const u16_t uip_hostaddr[2] =
+  {HTONS((UIP_IPADDR0 << 8) | UIP_IPADDR1),
+   HTONS((UIP_IPADDR2 << 8) | UIP_IPADDR3)};
+const u16_t uip_arp_draddr[2] =
+  {HTONS((UIP_DRIPADDR0 << 8) | UIP_DRIPADDR1),
+   HTONS((UIP_DRIPADDR2 << 8) | UIP_DRIPADDR3)};
+const u16_t uip_arp_netmask[2] =
+  {HTONS((UIP_NETMASK0 << 8) | UIP_NETMASK1),
+   HTONS((UIP_NETMASK2 << 8) | UIP_NETMASK3)};
+#else
+u16_t uip_hostaddr[2];       
+u16_t uip_arp_draddr[2], uip_arp_netmask[2];
+#endif /* UIP_FIXEDADDR */
+
+u8_t uip_buf[UIP_BUFSIZE+2];   /* The packet buffer that contains
+				incoming packets. */
+volatile u8_t *uip_appdata;  /* The uip_appdata pointer points to
+				application data. */
+volatile u8_t *uip_sappdata;  /* The uip_appdata pointer points to the
+				 application data which is to be sent. */
+#if UIP_URGDATA > 0
+volatile u8_t *uip_urgdata;  /* The uip_urgdata pointer points to
+				urgent data (out-of-band data), if
+				present. */
+volatile u8_t uip_urglen, uip_surglen;
+#endif /* UIP_URGDATA > 0 */
+
+volatile u16_t uip_len, uip_slen;
+                             /* The uip_len is either 8 or 16 bits,
+				depending on the maximum packet
+				size. */
+
+volatile u8_t uip_flags;     /* The uip_flags variable is used for
+				communication between the TCP/IP stack
+				and the application program. */
+struct uip_conn *uip_conn;   /* uip_conn always points to the current
+				connection. */
+
+struct uip_conn uip_conns[UIP_CONNS];
+                             /* The uip_conns array holds all TCP
+				connections. */
+u16_t uip_listenports[UIP_LISTENPORTS];
+                             /* The uip_listenports list all currently
+				listning ports. */
+#if UIP_UDP
+struct uip_udp_conn *uip_udp_conn;
+struct uip_udp_conn uip_udp_conns[UIP_UDP_CONNS];
+#endif /* UIP_UDP */
+
+
+static u16_t ipid;           /* Ths ipid variable is an increasing
+				number that is used for the IP ID
+				field. */
+
+static u8_t iss[4];          /* The iss variable is used for the TCP
+				initial sequence number. */
+
+#if UIP_ACTIVE_OPEN
+static u16_t lastport;       /* Keeps track of the last port used for
+				a new connection. */
+#endif /* UIP_ACTIVE_OPEN */
+
+/* Temporary variables. */
+volatile u8_t uip_acc32[4];
+static u8_t c, opt;
+static u16_t tmp16;
+
+/* Structures and definitions. */
+#define TCP_FIN 0x01
+#define TCP_SYN 0x02
+#define TCP_RST 0x04
+#define TCP_PSH 0x08
+#define TCP_ACK 0x10
+#define TCP_URG 0x20
+#define TCP_CTL 0x3f
+
+#define ICMP_ECHO_REPLY 0
+#define ICMP_ECHO       8     
+
+/* Macros. */
+#define BUF ((uip_tcpip_hdr *)&uip_buf[UIP_LLH_LEN])
+#define FBUF ((uip_tcpip_hdr *)&uip_reassbuf[0])
+#define ICMPBUF ((uip_icmpip_hdr *)&uip_buf[UIP_LLH_LEN])
+#define UDPBUF ((uip_udpip_hdr *)&uip_buf[UIP_LLH_LEN])
+
+#if UIP_STATISTICS == 1
+struct uip_stats uip_stat;
+#define UIP_STAT(s) s
+#else
+#define UIP_STAT(s)
+#endif /* UIP_STATISTICS == 1 */
+
+#if UIP_LOGGING == 1
+#include <stdio.h>
+void uip_log(char *msg);
+#define UIP_LOG(m) uip_log(m)
+#else
+#define UIP_LOG(m)
+#endif /* UIP_LOGGING == 1 */
+
+/*-----------------------------------------------------------------------------------*/
+void
+uip_init(void)
+{
+  for(c = 0; c < UIP_LISTENPORTS; ++c) {
+    uip_listenports[c] = 0;
+  }
+  for(c = 0; c < UIP_CONNS; ++c) {
+    uip_conns[c].tcpstateflags = CLOSED;
+  }
+#if UIP_ACTIVE_OPEN
+  lastport = 1024;
+#endif /* UIP_ACTIVE_OPEN */
+
+#if UIP_UDP
+  for(c = 0; c < UIP_UDP_CONNS; ++c) {
+    uip_udp_conns[c].lport = 0;
+  }
+#endif /* UIP_UDP */
+  
+
+  /* IPv4 initialization. */
+#if UIP_FIXEDADDR == 0
+  uip_hostaddr[0] = uip_hostaddr[1] = 0;
+#endif /* UIP_FIXEDADDR */
+
+}
+/*-----------------------------------------------------------------------------------*/
+#if UIP_ACTIVE_OPEN
+struct uip_conn *
+uip_connect(u16_t *ripaddr, u16_t rport)
+{
+  register struct uip_conn *conn, *cconn;
+  
+  /* Find an unused local port. */
+ again:
+  ++lastport;
+
+  if(lastport >= 32000) {
+    lastport = 4096;
+  }
+
+  /* Check if this port is already in use, and if so try to find
+     another one. */
+  for(c = 0; c < UIP_CONNS; ++c) {
+    conn = &uip_conns[c];
+    if(conn->tcpstateflags != CLOSED &&
+       conn->lport == htons(lastport)) {
+      goto again;
+    }
+  }
+
+
+  conn = 0;
+  for(c = 0; c < UIP_CONNS; ++c) {
+    cconn = &uip_conns[c]; 
+    if(cconn->tcpstateflags == CLOSED) {
+      conn = cconn;
+      break;
+    }
+    if(cconn->tcpstateflags == TIME_WAIT) {
+      if(conn == 0 ||
+	 cconn->timer > uip_conn->timer) {
+	conn = cconn;
+      }
+    }
+  }
+
+  if(conn == 0) {
+    return 0;
+  }
+  
+  conn->tcpstateflags = SYN_SENT;
+
+  conn->snd_nxt[0] = iss[0];
+  conn->snd_nxt[1] = iss[1];
+  conn->snd_nxt[2] = iss[2];
+  conn->snd_nxt[3] = iss[3];
+
+  conn->initialmss = conn->mss = UIP_TCP_MSS;
+  
+  conn->len = 1;   /* TCP length of the SYN is one. */
+  conn->nrtx = 0;
+  conn->timer = 1; /* Send the SYN next time around. */
+  conn->rto = UIP_RTO;
+  conn->sa = 0;
+  conn->sv = 16;
+  conn->lport = htons(lastport);
+  conn->rport = rport;
+  conn->ripaddr[0] = ripaddr[0];
+  conn->ripaddr[1] = ripaddr[1];
+  
+  return conn;
+}
+#endif /* UIP_ACTIVE_OPEN */
+/*-----------------------------------------------------------------------------------*/
+#if UIP_UDP
+struct uip_udp_conn *
+uip_udp_new(u16_t *ripaddr, u16_t rport)
+{
+  register struct uip_udp_conn *conn;
+  
+  /* Find an unused local port. */
+ again:
+  ++lastport;
+
+  if(lastport >= 32000) {
+    lastport = 4096;
+  }
+  
+  for(c = 0; c < UIP_UDP_CONNS; ++c) {
+    if(uip_udp_conns[c].lport == lastport) {
+      goto again;
+    }
+  }
+
+
+  conn = 0;
+  for(c = 0; c < UIP_UDP_CONNS; ++c) {
+    if(uip_udp_conns[c].lport == 0) {
+      conn = &uip_udp_conns[c]; 
+      break;
+    }
+  }
+
+  if(conn == 0) {
+    return 0;
+  }
+  
+  conn->lport = HTONS(lastport);
+  conn->rport = HTONS(rport);
+  conn->ripaddr[0] = ripaddr[0];
+  conn->ripaddr[1] = ripaddr[1];
+  
+  return conn;
+}
+#endif /* UIP_UDP */
+/*-----------------------------------------------------------------------------------*/
+void
+uip_unlisten(u16_t port)
+{
+  for(c = 0; c < UIP_LISTENPORTS; ++c) {
+    if(uip_listenports[c] == port) {
+      uip_listenports[c] = 0;
+      return;
+    }
+  }
+}
+/*-----------------------------------------------------------------------------------*/
+void
+uip_listen(u16_t port)
+{
+  for(c = 0; c < UIP_LISTENPORTS; ++c) {
+    if(uip_listenports[c] == 0) {
+      uip_listenports[c] = port;
+      return;
+    }
+  }
+}
+/*-----------------------------------------------------------------------------------*/
+/* XXX: IP fragment reassembly: not well-tested. */
+
+#if UIP_REASSEMBLY
+#define UIP_REASS_BUFSIZE (UIP_BUFSIZE - UIP_LLH_LEN)
+static u8_t uip_reassbuf[UIP_REASS_BUFSIZE];
+static u8_t uip_reassbitmap[UIP_REASS_BUFSIZE / (8 * 8)];
+static const u8_t bitmap_bits[8] = {0xff, 0x7f, 0x3f, 0x1f,
+				    0x0f, 0x07, 0x03, 0x01};
+static u16_t uip_reasslen;
+static u8_t uip_reassflags;
+#define UIP_REASS_FLAG_LASTFRAG 0x01
+static u8_t uip_reasstmr;
+
+#define IP_HLEN 20
+#define IP_MF   0x20
+
+static u8_t
+uip_reass(void)
+{
+  u16_t offset, len;
+  u16_t i;
+
+  /* If ip_reasstmr is zero, no packet is present in the buffer, so we
+     write the IP header of the fragment into the reassembly
+     buffer. The timer is updated with the maximum age. */
+  if(uip_reasstmr == 0) {
+    memcpy(uip_reassbuf, &BUF->vhl, IP_HLEN);
+    uip_reasstmr = UIP_REASS_MAXAGE;
+    uip_reassflags = 0;
+    /* Clear the bitmap. */
+    memset(uip_reassbitmap, sizeof(uip_reassbitmap), 0);
+  }
+
+  /* Check if the incoming fragment matches the one currently present
+     in the reasembly buffer. If so, we proceed with copying the
+     fragment into the buffer. */
+  if(BUF->srcipaddr[0] == FBUF->srcipaddr[0] &&
+     BUF->srcipaddr[1] == FBUF->srcipaddr[1] &&
+     BUF->destipaddr[0] == FBUF->destipaddr[0] &&
+     BUF->destipaddr[1] == FBUF->destipaddr[1] &&
+     BUF->ipid[0] == FBUF->ipid[0] &&
+     BUF->ipid[1] == FBUF->ipid[1]) {
+
+    len = (BUF->len[0] << 8) + BUF->len[1] - (BUF->vhl & 0x0f) * 4;
+    offset = (((BUF->ipoffset[0] & 0x3f) << 8) + BUF->ipoffset[1]) * 8;
+
+    /* If the offset or the offset + fragment length overflows the
+       reassembly buffer, we discard the entire packet. */
+    if(offset > UIP_REASS_BUFSIZE ||
+       offset + len > UIP_REASS_BUFSIZE) {
+      uip_reasstmr = 0;
+      goto nullreturn;
+    }
+
+    /* Copy the fragment into the reassembly buffer, at the right
+       offset. */
+    memcpy(&uip_reassbuf[IP_HLEN + offset],
+	   (char *)BUF + (int)((BUF->vhl & 0x0f) * 4),
+	   len);
+      
+    /* Update the bitmap. */
+    if(offset / (8 * 8) == (offset + len) / (8 * 8)) {
+      /* If the two endpoints are in the same byte, we only update
+	 that byte. */
+	     
+      uip_reassbitmap[offset / (8 * 8)] |=
+	     bitmap_bits[(offset / 8 ) & 7] &
+	     ~bitmap_bits[((offset + len) / 8 ) & 7];
+    } else {
+      /* If the two endpoints are in different bytes, we update the
+	 bytes in the endpoints and fill the stuff inbetween with
+	 0xff. */
+      uip_reassbitmap[offset / (8 * 8)] |=
+	bitmap_bits[(offset / 8 ) & 7];
+      for(i = 1 + offset / (8 * 8); i < (offset + len) / (8 * 8); ++i) {
+	uip_reassbitmap[i] = 0xff;
+      }      
+      uip_reassbitmap[(offset + len) / (8 * 8)] |=
+	~bitmap_bits[((offset + len) / 8 ) & 7];
+    }
+    
+    /* If this fragment has the More Fragments flag set to zero, we
+       know that this is the last fragment, so we can calculate the
+       size of the entire packet. We also set the
+       IP_REASS_FLAG_LASTFRAG flag to indicate that we have received
+       the final fragment. */
+
+    if((BUF->ipoffset[0] & IP_MF) == 0) {
+      uip_reassflags |= UIP_REASS_FLAG_LASTFRAG;
+      uip_reasslen = offset + len;
+    }
+    
+    /* Finally, we check if we have a full packet in the buffer. We do
+       this by checking if we have the last fragment and if all bits
+       in the bitmap are set. */
+    if(uip_reassflags & UIP_REASS_FLAG_LASTFRAG) {
+      /* Check all bytes up to and including all but the last byte in
+	 the bitmap. */
+      for(i = 0; i < uip_reasslen / (8 * 8) - 1; ++i) {
+	if(uip_reassbitmap[i] != 0xff) {
+	  goto nullreturn;
+	}
+      }
+      /* Check the last byte in the bitmap. It should contain just the
+	 right amount of bits. */
+      if(uip_reassbitmap[uip_reasslen / (8 * 8)] !=
+	 (u8_t)~bitmap_bits[uip_reasslen / 8 & 7]) {
+	goto nullreturn;
+      }
+
+      /* If we have come this far, we have a full packet in the
+	 buffer, so we allocate a pbuf and copy the packet into it. We
+	 also reset the timer. */
+      uip_reasstmr = 0;
+      memcpy(BUF, FBUF, uip_reasslen);
+
+      /* Pretend to be a "normal" (i.e., not fragmented) IP packet
+	 from now on. */
+      BUF->ipoffset[0] = BUF->ipoffset[1] = 0;
+      BUF->len[0] = uip_reasslen >> 8;
+      BUF->len[1] = uip_reasslen & 0xff;
+      BUF->ipchksum = 0;
+      BUF->ipchksum = ~(uip_ipchksum());
+
+      return uip_reasslen;
+    }
+  }
+
+ nullreturn:
+  return 0;
+}
+#endif /* UIP_REASSEMBL */
+/*-----------------------------------------------------------------------------------*/
+static void
+uip_add_rcv_nxt(u16_t n)
+{
+  uip_add32(uip_conn->rcv_nxt, n);
+  uip_conn->rcv_nxt[0] = uip_acc32[0];
+  uip_conn->rcv_nxt[1] = uip_acc32[1];
+  uip_conn->rcv_nxt[2] = uip_acc32[2];
+  uip_conn->rcv_nxt[3] = uip_acc32[3];
+}
+/*-----------------------------------------------------------------------------------*/
+void
+uip_process(u8_t flag)
+{
+  register struct uip_conn *uip_connr = uip_conn;
+  
+  uip_appdata = &uip_buf[40 + UIP_LLH_LEN];
+
+  
+  /* Check if we were invoked because of the perodic timer fireing. */
+  if(flag == UIP_TIMER) {
+#if UIP_REASSEMBLY
+    if(uip_reasstmr != 0) {
+      --uip_reasstmr;
+    }
+#endif /* UIP_REASSEMBLY */
+    /* Increase the initial sequence number. */
+    if(++iss[3] == 0) {
+      if(++iss[2] == 0) {
+	if(++iss[1] == 0) {
+	  ++iss[0];
+	}
+      }
+    }    
+    uip_len = 0;
+    if(uip_connr->tcpstateflags == TIME_WAIT ||
+       uip_connr->tcpstateflags == FIN_WAIT_2) {
+      ++(uip_connr->timer);
+      if(uip_connr->timer == UIP_TIME_WAIT_TIMEOUT) {
+	uip_connr->tcpstateflags = CLOSED;
+      }
+    } else if(uip_connr->tcpstateflags != CLOSED) {
+      /* If the connection has outstanding data, we increase the
+	 connection's timer and see if it has reached the RTO value
+	 in which case we retransmit. */
+      if(uip_outstanding(uip_connr)) {
+	if(uip_connr->timer-- == 0) {
+	  if(uip_connr->nrtx == UIP_MAXRTX ||
+	     ((uip_connr->tcpstateflags == SYN_SENT ||
+	       uip_connr->tcpstateflags == SYN_RCVD) &&
+	      uip_connr->nrtx == UIP_MAXSYNRTX)) {
+	    uip_connr->tcpstateflags = CLOSED;
+
+	    /* We call UIP_APPCALL() with uip_flags set to
+	       UIP_TIMEDOUT to inform the application that the
+	       connection has timed out. */
+	    uip_flags = UIP_TIMEDOUT;
+	    UIP_APPCALL();
+
+	    /* We also send a reset packet to the remote host. */
+	    BUF->flags = TCP_RST | TCP_ACK;
+	    goto tcp_send_nodata;
+	  }
+
+	  /* Exponential backoff. */
+	  uip_connr->timer = UIP_RTO << (uip_connr->nrtx > 4?
+					 4:
+					 uip_connr->nrtx);
+	  ++(uip_connr->nrtx);
+	  
+	  /* Ok, so we need to retransmit. We do this differently
+	     depending on which state we are in. In ESTABLISHED, we
+	     call upon the application so that it may prepare the
+	     data for the retransmit. In SYN_RCVD, we resend the
+	     SYNACK that we sent earlier and in LAST_ACK we have to
+	     retransmit our FINACK. */
+	  UIP_STAT(++uip_stat.tcp.rexmit);
+	  switch(uip_connr->tcpstateflags & TS_MASK) {
+	  case SYN_RCVD:
+	    /* In the SYN_RCVD state, we should retransmit our
+               SYNACK. */
+	    goto tcp_send_synack;
+	    
+#if UIP_ACTIVE_OPEN
+	  case SYN_SENT:
+	    /* In the SYN_SENT state, we retransmit out SYN. */
+	    BUF->flags = 0;
+	    goto tcp_send_syn;
+#endif /* UIP_ACTIVE_OPEN */
+	    
+	  case ESTABLISHED:
+	    /* In the ESTABLISHED state, we call upon the application
+               to do the actual retransmit after which we jump into
+               the code for sending out the packet (the apprexmit
+               label). */
+	    uip_len = 0;
+	    uip_slen = 0;
+	    uip_flags = UIP_REXMIT;
+	    UIP_APPCALL();
+	    goto apprexmit;
+	    
+	  case FIN_WAIT_1:
+	  case CLOSING:
+	  case LAST_ACK:
+	    /* In all these states we should retransmit a FINACK. */
+	    goto tcp_send_finack;
+	    
+	  }
+	}
+      } else if((uip_connr->tcpstateflags & TS_MASK) == ESTABLISHED) {
+	/* If there was no need for a retransmission, we poll the
+           application for new data. */
+	uip_len = 0;
+	uip_slen = 0;
+	uip_flags = UIP_POLL;
+	UIP_APPCALL();
+	goto appsend;
+      }
+    }
+    goto drop;
+  }
+#if UIP_UDP 
+  if(flag == UIP_UDP_TIMER) {
+    if(uip_udp_conn->lport != 0) {
+      uip_appdata = &uip_buf[UIP_LLH_LEN + 28];
+      uip_len = uip_slen = 0;
+      uip_flags = UIP_POLL;
+      UIP_UDP_APPCALL();
+      goto udp_send;
+    } else {
+      goto drop;
+    }
+  }
+#endif
+
+  /* This is where the input processing starts. */
+  UIP_STAT(++uip_stat.ip.recv);
+
+
+  /* Start of IPv4 input header processing code. */
+  
+  /* Check validity of the IP header. */  
+  if(BUF->vhl != 0x45)  { /* IP version and header length. */
+    UIP_STAT(++uip_stat.ip.drop);
+    UIP_STAT(++uip_stat.ip.vhlerr);
+    UIP_LOG("ip: invalid version or header length.");
+    goto drop;
+  }
+  
+  /* Check the size of the packet. If the size reported to us in
+     uip_len doesn't match the size reported in the IP header, there
+     has been a transmission error and we drop the packet. */
+  
+  if(BUF->len[0] != (uip_len >> 8)) { /* IP length, high byte. */
+    uip_len = (uip_len & 0xff) | (BUF->len[0] << 8);
+  }
+  if(BUF->len[1] != (uip_len & 0xff)) { /* IP length, low byte. */
+    uip_len = (uip_len & 0xff00) | BUF->len[1];
+  }
+
+  /* Check the fragment flag. */
+  if((BUF->ipoffset[0] & 0x3f) != 0 ||
+     BUF->ipoffset[1] != 0) { 
+#if UIP_REASSEMBLY
+    uip_len = uip_reass();
+    if(uip_len == 0) {
+      goto drop;
+    }
+#else
+    UIP_STAT(++uip_stat.ip.drop);
+    UIP_STAT(++uip_stat.ip.fragerr);
+    UIP_LOG("ip: fragment dropped.");    
+    goto drop;
+#endif /* UIP_REASSEMBLY */
+  }
+
+  /* If we are configured to use ping IP address configuration and
+     hasn't been assigned an IP address yet, we accept all ICMP
+     packets. */
+#if UIP_PINGADDRCONF
+  if((uip_hostaddr[0] | uip_hostaddr[1]) == 0) {
+    if(BUF->proto == UIP_PROTO_ICMP) {
+      UIP_LOG("ip: possible ping config packet received.");
+      goto icmp_input;
+    } else {
+      UIP_LOG("ip: packet dropped since no address assigned.");
+      goto drop;
+    }
+  }
+#endif /* UIP_PINGADDRCONF */
+  
+  /* Check if the packet is destined for our IP address. */  
+  if(BUF->destipaddr[0] != uip_hostaddr[0]) {
+    UIP_STAT(++uip_stat.ip.drop);
+    UIP_LOG("ip: packet not for us.");        
+    goto drop;
+  }
+  if(BUF->destipaddr[1] != uip_hostaddr[1]) {
+    UIP_STAT(++uip_stat.ip.drop);
+    UIP_LOG("ip: packet not for us.");        
+    goto drop;
+  }
+
+  if(uip_ipchksum() != 0xffff) { /* Compute and check the IP header
+				    checksum. */
+    UIP_STAT(++uip_stat.ip.drop);
+    UIP_STAT(++uip_stat.ip.chkerr);
+    UIP_LOG("ip: bad checksum.");    
+    goto drop;
+  }
+
+  if(BUF->proto == UIP_PROTO_TCP)  /* Check for TCP packet. If so, jump
+                                     to the tcp_input label. */
+    goto tcp_input;
+
+#if UIP_UDP
+  if(BUF->proto == UIP_PROTO_UDP)
+    goto udp_input;
+#endif /* UIP_UDP */
+
+  if(BUF->proto != UIP_PROTO_ICMP) { /* We only allow ICMP packets from
+					here. */
+    UIP_STAT(++uip_stat.ip.drop);
+    UIP_STAT(++uip_stat.ip.protoerr);
+    UIP_LOG("ip: neither tcp nor icmp.");        
+    goto drop;
+  }
+  
+ icmp_input:
+  UIP_STAT(++uip_stat.icmp.recv);
+  
+  /* ICMP echo (i.e., ping) processing. This is simple, we only change
+     the ICMP type from ECHO to ECHO_REPLY and adjust the ICMP
+     checksum before we return the packet. */
+  if(ICMPBUF->type != ICMP_ECHO) {
+    UIP_STAT(++uip_stat.icmp.drop);
+    UIP_STAT(++uip_stat.icmp.typeerr);
+    UIP_LOG("icmp: not icmp echo.");
+    goto drop;
+  }
+
+  /* If we are configured to use ping IP address assignment, we use
+     the destination IP address of this ping packet and assign it to
+     ourself. */
+#if UIP_PINGADDRCONF
+  if((uip_hostaddr[0] | uip_hostaddr[1]) == 0) {
+    uip_hostaddr[0] = BUF->destipaddr[0];
+    uip_hostaddr[1] = BUF->destipaddr[1];
+  }
+#endif /* UIP_PINGADDRCONF */  
+  
+  ICMPBUF->type = ICMP_ECHO_REPLY;
+  
+  if(ICMPBUF->icmpchksum >= HTONS(0xffff - (ICMP_ECHO << 8))) {
+    ICMPBUF->icmpchksum += HTONS(ICMP_ECHO << 8) + 1;
+  } else {
+    ICMPBUF->icmpchksum += HTONS(ICMP_ECHO << 8);
+  }
+  
+  /* Swap IP addresses. */
+  tmp16 = BUF->destipaddr[0];
+  BUF->destipaddr[0] = BUF->srcipaddr[0];
+  BUF->srcipaddr[0] = tmp16;
+  tmp16 = BUF->destipaddr[1];
+  BUF->destipaddr[1] = BUF->srcipaddr[1];
+  BUF->srcipaddr[1] = tmp16;
+
+  UIP_STAT(++uip_stat.icmp.sent);
+  goto send;
+
+  /* End of IPv4 input header processing code. */
+  
+
+#if UIP_UDP
+  /* UDP input processing. */
+ udp_input:
+  /* UDP processing is really just a hack. We don't do anything to the
+     UDP/IP headers, but let the UDP application do all the hard
+     work. If the application sets uip_slen, it has a packet to
+     send. */
+#if UIP_UDP_CHECKSUMS
+  if(uip_udpchksum() != 0xffff) { 
+    UIP_STAT(++uip_stat.udp.drop);
+    UIP_STAT(++uip_stat.udp.chkerr);
+    UIP_LOG("udp: bad checksum.");    
+    goto drop;
+  }  
+#endif /* UIP_UDP_CHECKSUMS */
+
+  /* Demultiplex this UDP packet between the UDP "connections". */
+  for(uip_udp_conn = &uip_udp_conns[0];
+      uip_udp_conn < &uip_udp_conns[UIP_UDP_CONNS];
+      ++uip_udp_conn) {
+    if(uip_udp_conn->lport != 0 &&
+       UDPBUF->destport == uip_udp_conn->lport &&
+       (uip_udp_conn->rport == 0 ||
+        UDPBUF->srcport == uip_udp_conn->rport) &&
+       BUF->srcipaddr[0] == uip_udp_conn->ripaddr[0] &&
+       BUF->srcipaddr[1] == uip_udp_conn->ripaddr[1]) {
+      goto udp_found; 
+    }
+  }
+  goto drop;
+  
+ udp_found:
+  uip_len = uip_len - 28;
+  uip_appdata = &uip_buf[UIP_LLH_LEN + 28];
+  uip_flags = UIP_NEWDATA;
+  uip_slen = 0;
+  UIP_UDP_APPCALL();
+ udp_send:
+  if(uip_slen == 0) {
+    goto drop;      
+  }
+  uip_len = uip_slen + 28;
+
+  BUF->len[0] = (uip_len >> 8);
+  BUF->len[1] = (uip_len & 0xff);
+  
+  BUF->proto = UIP_PROTO_UDP;
+
+  UDPBUF->udplen = HTONS(uip_slen + 8);
+  UDPBUF->udpchksum = 0;
+#if UIP_UDP_CHECKSUMS 
+  /* Calculate UDP checksum. */
+  UDPBUF->udpchksum = ~(uip_udpchksum());
+  if(UDPBUF->udpchksum == 0) {
+    UDPBUF->udpchksum = 0xffff;
+  }
+#endif /* UIP_UDP_CHECKSUMS */
+
+  BUF->srcport  = uip_udp_conn->lport;
+  BUF->destport = uip_udp_conn->rport;
+
+  BUF->srcipaddr[0] = uip_hostaddr[0];
+  BUF->srcipaddr[1] = uip_hostaddr[1];
+  BUF->destipaddr[0] = uip_udp_conn->ripaddr[0];
+  BUF->destipaddr[1] = uip_udp_conn->ripaddr[1];
+ 
+  uip_appdata = &uip_buf[UIP_LLH_LEN + 40];
+  goto ip_send_nolen;
+#endif /* UIP_UDP */
+  
+  /* TCP input processing. */  
+ tcp_input:
+  UIP_STAT(++uip_stat.tcp.recv);
+
+  /* Start of TCP input header processing code. */
+  
+  if(uip_tcpchksum() != 0xffff) {   /* Compute and check the TCP
+				       checksum. */
+    UIP_STAT(++uip_stat.tcp.drop);
+    UIP_STAT(++uip_stat.tcp.chkerr);
+    UIP_LOG("tcp: bad checksum.");    
+    goto drop;
+  }
+  
+  /* Demultiplex this segment. */
+  /* First check any active connections. */
+  for(uip_connr = &uip_conns[0]; uip_connr < &uip_conns[UIP_CONNS]; ++uip_connr) {
+    if(uip_connr->tcpstateflags != CLOSED &&
+       BUF->destport == uip_connr->lport &&
+       BUF->srcport == uip_connr->rport &&
+       BUF->srcipaddr[0] == uip_connr->ripaddr[0] &&
+       BUF->srcipaddr[1] == uip_connr->ripaddr[1]) {
+      goto found;    
+    }
+  }
+
+  /* If we didn't find and active connection that expected the packet,
+     either this packet is an old duplicate, or this is a SYN packet
+     destined for a connection in LISTEN. If the SYN flag isn't set,
+     it is an old packet and we send a RST. */
+  if((BUF->flags & TCP_CTL) != TCP_SYN)
+    goto reset;
+  
+  tmp16 = BUF->destport;
+  /* Next, check listening connections. */  
+  for(c = 0; c < UIP_LISTENPORTS; ++c) {
+    if(tmp16 == uip_listenports[c])
+      goto found_listen;
+  }
+  
+  /* No matching connection found, so we send a RST packet. */
+  UIP_STAT(++uip_stat.tcp.synrst);
+ reset:
+
+  /* We do not send resets in response to resets. */
+  if(BUF->flags & TCP_RST) 
+    goto drop;
+
+  UIP_STAT(++uip_stat.tcp.rst);
+  
+  BUF->flags = TCP_RST | TCP_ACK;
+  uip_len = 40;
+  BUF->tcpoffset = 5 << 4;
+
+  /* Flip the seqno and ackno fields in the TCP header. */
+  c = BUF->seqno[3];
+  BUF->seqno[3] = BUF->ackno[3];  
+  BUF->ackno[3] = c;
+  
+  c = BUF->seqno[2];
+  BUF->seqno[2] = BUF->ackno[2];  
+  BUF->ackno[2] = c;
+  
+  c = BUF->seqno[1];
+  BUF->seqno[1] = BUF->ackno[1];
+  BUF->ackno[1] = c;
+  
+  c = BUF->seqno[0];
+  BUF->seqno[0] = BUF->ackno[0];  
+  BUF->ackno[0] = c;
+
+  /* We also have to increase the sequence number we are
+     acknowledging. If the least significant byte overflowed, we need
+     to propagate the carry to the other bytes as well. */
+  if(++BUF->ackno[3] == 0) {
+    if(++BUF->ackno[2] == 0) {
+      if(++BUF->ackno[1] == 0) {
+	++BUF->ackno[0];
+      }
+    }
+  }
+ 
+  /* Swap port numbers. */
+  tmp16 = BUF->srcport;
+  BUF->srcport = BUF->destport;
+  BUF->destport = tmp16;
+  
+  /* Swap IP addresses. */
+  tmp16 = BUF->destipaddr[0];
+  BUF->destipaddr[0] = BUF->srcipaddr[0];
+  BUF->srcipaddr[0] = tmp16;
+  tmp16 = BUF->destipaddr[1];
+  BUF->destipaddr[1] = BUF->srcipaddr[1];
+  BUF->srcipaddr[1] = tmp16;
+
+  
+  /* And send out the RST packet! */
+  goto tcp_send_noconn;
+
+  /* This label will be jumped to if we matched the incoming packet
+     with a connection in LISTEN. In that case, we should create a new
+     connection and send a SYNACK in return. */
+ found_listen:
+  /* First we check if there are any connections avaliable. Unused
+     connections are kept in the same table as used connections, but
+     unused ones have the tcpstate set to CLOSED. Also, connections in
+     TIME_WAIT are kept track of and we'll use the oldest one if no
+     CLOSED connections are found. Thanks to Eddie C. Dost for a very
+     nice algorithm for the TIME_WAIT search. */
+  uip_connr = 0;
+  for(c = 0; c < UIP_CONNS; ++c) {
+    if(uip_conns[c].tcpstateflags == CLOSED) {
+      uip_connr = &uip_conns[c];
+      break;
+    }
+    if(uip_conns[c].tcpstateflags == TIME_WAIT) {
+      if(uip_connr == 0 ||
+	 uip_conns[c].timer > uip_connr->timer) {
+	uip_connr = &uip_conns[c];
+      }
+    }
+  }
+
+  if(uip_connr == 0) {
+    /* All connections are used already, we drop packet and hope that
+       the remote end will retransmit the packet at a time when we
+       have more spare connections. */
+    UIP_STAT(++uip_stat.tcp.syndrop);
+    UIP_LOG("tcp: found no unused connections.");
+    goto drop;
+  }
+  uip_conn = uip_connr;
+  
+  /* Fill in the necessary fields for the new connection. */
+  uip_connr->rto = uip_connr->timer = UIP_RTO;
+  uip_connr->sa = 0;
+  uip_connr->sv = 4;  
+  uip_connr->nrtx = 0;
+  uip_connr->lport = BUF->destport;
+  uip_connr->rport = BUF->srcport;
+  uip_connr->ripaddr[0] = BUF->srcipaddr[0];
+  uip_connr->ripaddr[1] = BUF->srcipaddr[1];
+  uip_connr->tcpstateflags = SYN_RCVD;
+
+  uip_connr->snd_nxt[0] = iss[0];
+  uip_connr->snd_nxt[1] = iss[1];
+  uip_connr->snd_nxt[2] = iss[2];
+  uip_connr->snd_nxt[3] = iss[3];
+  uip_connr->len = 1;
+
+  /* rcv_nxt should be the seqno from the incoming packet + 1. */
+  uip_connr->rcv_nxt[3] = BUF->seqno[3];
+  uip_connr->rcv_nxt[2] = BUF->seqno[2];
+  uip_connr->rcv_nxt[1] = BUF->seqno[1];
+  uip_connr->rcv_nxt[0] = BUF->seqno[0];
+  uip_add_rcv_nxt(1);
+
+  /* Parse the TCP MSS option, if present. */
+  if((BUF->tcpoffset & 0xf0) > 0x50) {
+    for(c = 0; c < ((BUF->tcpoffset >> 4) - 5) << 2 ;) {
+      opt = uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + c];
+      if(opt == 0x00) {
+	/* End of options. */	
+	break;
+      } else if(opt == 0x01) {
+	++c;
+	/* NOP option. */
+      } else if(opt == 0x02 &&
+		uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == 0x04) {
+	/* An MSS option with the right option length. */	
+	tmp16 = ((u16_t)uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + c] << 8) |
+	  (u16_t)uip_buf[40 + UIP_LLH_LEN + 3 + c];
+	uip_connr->initialmss = uip_connr->mss =
+	  tmp16 > UIP_TCP_MSS? UIP_TCP_MSS: tmp16;
+	
+	/* And we are done processing options. */
+	break;
+      } else {
+	/* All other options have a length field, so that we easily
+	   can skip past them. */
+	if(uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == 0) {
+	  /* If the length field is zero, the options are malformed
+	     and we don't process them further. */
+	  break;
+	}
+	c += uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c];
+      }      
+    }
+  }
+  
+  /* Our response will be a SYNACK. */
+#if UIP_ACTIVE_OPEN
+ tcp_send_synack:
+  BUF->flags = TCP_ACK;    
+  
+ tcp_send_syn:
+  BUF->flags |= TCP_SYN;    
+#else /* UIP_ACTIVE_OPEN */
+ tcp_send_synack:
+  BUF->flags = TCP_SYN | TCP_ACK;    
+#endif /* UIP_ACTIVE_OPEN */
+  
+  /* We send out the TCP Maximum Segment Size option with our
+     SYNACK. */
+  BUF->optdata[0] = 2;
+  BUF->optdata[1] = 4;
+  BUF->optdata[2] = (UIP_TCP_MSS) / 256;
+  BUF->optdata[3] = (UIP_TCP_MSS) & 255;
+  uip_len = 44;
+  BUF->tcpoffset = 6 << 4;
+  goto tcp_send;
+
+  /* This label will be jumped to if we found an active connection. */
+ found:
+  uip_conn = uip_connr;
+  uip_flags = 0;
+
+  /* We do a very naive form of TCP reset processing; we just accept
+     any RST and kill our connection. We should in fact check if the
+     sequence number of this reset is wihtin our advertised window
+     before we accept the reset. */
+  if(BUF->flags & TCP_RST) {
+    uip_connr->tcpstateflags = CLOSED;
+    UIP_LOG("tcp: got reset, aborting connection.");
+    uip_flags = UIP_ABORT;
+    UIP_APPCALL();
+    goto drop;
+  }      
+  /* Calculated the length of the data, if the application has sent
+     any data to us. */
+  c = (BUF->tcpoffset >> 4) << 2;
+  /* uip_len will contain the length of the actual TCP data. This is
+     calculated by subtracing the length of the TCP header (in
+     c) and the length of the IP header (20 bytes). */
+  uip_len = uip_len - c - 20;
+
+  /* First, check if the sequence number of the incoming packet is
+     what we're expecting next. If not, we send out an ACK with the
+     correct numbers in. */
+  if(uip_len > 0 &&
+     (BUF->seqno[0] != uip_connr->rcv_nxt[0] ||
+      BUF->seqno[1] != uip_connr->rcv_nxt[1] ||
+      BUF->seqno[2] != uip_connr->rcv_nxt[2] ||
+      BUF->seqno[3] != uip_connr->rcv_nxt[3])) {
+    goto tcp_send_ack;
+  }
+
+  /* Next, check if the incoming segment acknowledges any outstanding
+     data. If so, we update the sequence number, reset the length of
+     the outstanding data, calculate RTT estimations, and reset the
+     retransmission timer. */
+  if((BUF->flags & TCP_ACK) && uip_outstanding(uip_connr)) {
+    uip_add32(uip_connr->snd_nxt, uip_connr->len);
+    if(BUF->ackno[0] == uip_acc32[0] &&
+       BUF->ackno[1] == uip_acc32[1] &&
+       BUF->ackno[2] == uip_acc32[2] &&
+       BUF->ackno[3] == uip_acc32[3]) {
+      /* Update sequence number. */
+      uip_connr->snd_nxt[0] = uip_acc32[0];
+      uip_connr->snd_nxt[1] = uip_acc32[1];
+      uip_connr->snd_nxt[2] = uip_acc32[2];
+      uip_connr->snd_nxt[3] = uip_acc32[3];
+	
+
+      /* Do RTT estimation, unless we have done retransmissions. */
+      if(uip_connr->nrtx == 0) {
+	signed char m;
+	m = uip_connr->rto - uip_connr->timer;
+	/* This is taken directly from VJs original code in his paper */
+	m = m - (uip_connr->sa >> 3);
+	uip_connr->sa += m;
+	if(m < 0) {
+	  m = -m;
+	}
+	m = m - (uip_connr->sv >> 2);
+	uip_connr->sv += m;
+	uip_connr->rto = (uip_connr->sa >> 3) + uip_connr->sv;
+
+      }
+      /* Set the acknowledged flag. */
+      uip_flags = UIP_ACKDATA;
+      /* Reset the retransmission timer. */
+      uip_connr->timer = uip_connr->rto;
+    }
+    
+  }
+
+  /* Do different things depending on in what state the connection is. */
+  switch(uip_connr->tcpstateflags & TS_MASK) {
+    /* CLOSED and LISTEN are not handled here. CLOSE_WAIT is not
+	implemented, since we force the application to close when the
+	peer sends a FIN (hence the application goes directly from
+	ESTABLISHED to LAST_ACK). */
+  case SYN_RCVD:
+    /* In SYN_RCVD we have sent out a SYNACK in response to a SYN, and
+       we are waiting for an ACK that acknowledges the data we sent
+       out the last time. Therefore, we want to have the UIP_ACKDATA
+       flag set. If so, we enter the ESTABLISHED state. */
+    if(uip_flags & UIP_ACKDATA) {
+      uip_connr->tcpstateflags = ESTABLISHED;
+      uip_flags = UIP_CONNECTED;
+      uip_connr->len = 0;
+      if(uip_len > 0) {
+        uip_flags |= UIP_NEWDATA;
+        uip_add_rcv_nxt(uip_len);
+      }
+      uip_slen = 0;
+      UIP_APPCALL();
+      goto appsend;
+    }
+    goto drop;
+#if UIP_ACTIVE_OPEN
+  case SYN_SENT:
+    /* In SYN_SENT, we wait for a SYNACK that is sent in response to
+       our SYN. The rcv_nxt is set to sequence number in the SYNACK
+       plus one, and we send an ACK. We move into the ESTABLISHED
+       state. */
+    if((uip_flags & UIP_ACKDATA) &&
+       BUF->flags == (TCP_SYN | TCP_ACK)) {
+
+      /* Parse the TCP MSS option, if present. */
+      if((BUF->tcpoffset & 0xf0) > 0x50) {
+	for(c = 0; c < ((BUF->tcpoffset >> 4) - 5) << 2 ;) {
+	  opt = uip_buf[40 + UIP_LLH_LEN + c];
+	  if(opt == 0x00) {
+	    /* End of options. */	
+	    break;
+	  } else if(opt == 0x01) {
+	    ++c;
+	    /* NOP option. */
+	  } else if(opt == 0x02 &&
+		    uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == 0x04) {
+	    /* An MSS option with the right option length. */
+	    tmp16 = (uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + c] << 8) |
+	      uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 3 + c];
+	    uip_connr->initialmss =
+	      uip_connr->mss = tmp16 > UIP_TCP_MSS? UIP_TCP_MSS: tmp16;
+
+	    /* And we are done processing options. */
+	    break;
+	  } else {
+	    /* All other options have a length field, so that we easily
+	       can skip past them. */
+	    if(uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == 0) {
+	      /* If the length field is zero, the options are malformed
+		 and we don't process them further. */
+	      break;
+	    }
+	    c += uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c];
+	  }      
+	}
+      }
+      uip_connr->tcpstateflags = ESTABLISHED;      
+      uip_connr->rcv_nxt[0] = BUF->seqno[0];
+      uip_connr->rcv_nxt[1] = BUF->seqno[1];
+      uip_connr->rcv_nxt[2] = BUF->seqno[2];
+      uip_connr->rcv_nxt[3] = BUF->seqno[3];
+      uip_add_rcv_nxt(1);
+      uip_flags = UIP_CONNECTED | UIP_NEWDATA;
+      uip_connr->len = 0;
+      uip_len = 0;
+      uip_slen = 0;
+      UIP_APPCALL();
+      goto appsend;
+    }
+    goto reset;
+#endif /* UIP_ACTIVE_OPEN */
+    
+  case ESTABLISHED:
+    /* In the ESTABLISHED state, we call upon the application to feed
+    data into the uip_buf. If the UIP_ACKDATA flag is set, the
+    application should put new data into the buffer, otherwise we are
+    retransmitting an old segment, and the application should put that
+    data into the buffer.
+
+    If the incoming packet is a FIN, we should close the connection on
+    this side as well, and we send out a FIN and enter the LAST_ACK
+    state. We require that there is no outstanding data; otherwise the
+    sequence numbers will be screwed up. */
+
+    if(BUF->flags & TCP_FIN) {
+      if(uip_outstanding(uip_connr)) {
+	goto drop;
+      }
+      uip_add_rcv_nxt(1 + uip_len);      
+      uip_flags = UIP_CLOSE;
+      if(uip_len > 0) {
+	uip_flags |= UIP_NEWDATA;
+      }
+      UIP_APPCALL();
+      uip_connr->len = 1;
+      uip_connr->tcpstateflags = LAST_ACK;
+      uip_connr->nrtx = 0;
+    tcp_send_finack:
+      BUF->flags = TCP_FIN | TCP_ACK;      
+      goto tcp_send_nodata;
+    }
+
+    /* Check the URG flag. If this is set, the segment carries urgent
+       data that we must pass to the application. */
+    if(BUF->flags & TCP_URG) {
+#if UIP_URGDATA > 0
+      uip_urglen = (BUF->urgp[0] << 8) | BUF->urgp[1];
+      if(uip_urglen > uip_len) {
+	/* There is more urgent data in the next segment to come. */
+	uip_urglen = uip_len;
+      }
+      uip_add_rcv_nxt(uip_urglen);
+      uip_len -= uip_urglen;
+      uip_urgdata = uip_appdata;
+      uip_appdata += uip_urglen;
+    } else {
+      uip_urglen = 0;
+#endif /* UIP_URGDATA > 0 */
+      uip_appdata += (BUF->urgp[0] << 8) | BUF->urgp[1];
+      uip_len -= (BUF->urgp[0] << 8) | BUF->urgp[1];
+    }
+    
+    
+    /* If uip_len > 0 we have TCP data in the packet, and we flag this
+       by setting the UIP_NEWDATA flag and update the sequence number
+       we acknowledge. If the application has stopped the dataflow
+       using uip_stop(), we must not accept any data packets from the
+       remote host. */
+    if(uip_len > 0 && !(uip_connr->tcpstateflags & UIP_STOPPED)) {
+      uip_flags |= UIP_NEWDATA;
+      uip_add_rcv_nxt(uip_len);
+    }
+
+    /* Check if the available buffer space advertised by the other end
+       is smaller than the initial MSS for this connection. If so, we
+       set the current MSS to the window size to ensure that the
+       application does not send more data than the other end can
+       handle.
+
+       If the remote host advertises a zero window, we set the MSS to
+       the initial MSS so that the application will send an entire MSS
+       of data. This data will not be acknowledged by the receiver,
+       and the application will retransmit it. This is called the
+       "persistent timer" and uses the retransmission mechanim.
+    */
+    tmp16 = ((u16_t)BUF->wnd[0] << 8) + (u16_t)BUF->wnd[1];
+    if(tmp16 > uip_connr->initialmss ||
+       tmp16 == 0) {
+      tmp16 = uip_connr->initialmss;
+    }
+    uip_connr->mss = tmp16;
+
+    /* If this packet constitutes an ACK for outstanding data (flagged
+       by the UIP_ACKDATA flag, we should call the application since it
+       might want to send more data. If the incoming packet had data
+       from the peer (as flagged by the UIP_NEWDATA flag), the
+       application must also be notified.
+
+       When the application is called, the global variable uip_len
+       contains the length of the incoming data. The application can
+       access the incoming data through the global pointer
+       uip_appdata, which usually points 40 bytes into the uip_buf
+       array.
+
+       If the application wishes to send any data, this data should be
+       put into the uip_appdata and the length of the data should be
+       put into uip_len. If the application don't have any data to
+       send, uip_len must be set to 0. */
+    if(uip_flags & (UIP_NEWDATA | UIP_ACKDATA)) {
+      uip_slen = 0;
+      UIP_APPCALL();
+
+    appsend:
+      
+      if(uip_flags & UIP_ABORT) {
+	uip_slen = 0;
+	uip_connr->tcpstateflags = CLOSED;
+	BUF->flags = TCP_RST | TCP_ACK;
+	goto tcp_send_nodata;
+      }
+
+      if(uip_flags & UIP_CLOSE) {
+	uip_slen = 0;
+	uip_connr->len = 1;
+	uip_connr->tcpstateflags = FIN_WAIT_1;
+	uip_connr->nrtx = 0;
+	BUF->flags = TCP_FIN | TCP_ACK;
+	goto tcp_send_nodata;	
+      }
+
+      /* If uip_slen > 0, the application has data to be sent. */
+      if(uip_slen > 0) {
+
+	/* If the connection has acknowledged data, the contents of
+	   the ->len variable should be discarded. */ 
+	if((uip_flags & UIP_ACKDATA) != 0) {
+	  uip_connr->len = 0;
+	}
+
+	/* If the ->len variable is non-zero the connection has
+	   already data in transit and cannot send anymore right
+	   now. */
+	if(uip_connr->len == 0) {
+
+	  /* The application cannot send more than what is allowed by
+	     the mss (the minumum of the MSS and the available
+	     window). */
+	  if(uip_slen > uip_connr->mss) {
+	    uip_slen = uip_connr->mss;
+	  }
+
+	  /* Remember how much data we send out now so that we know
+	     when everything has been acknowledged. */
+	  uip_connr->len = uip_slen;
+	} else {
+
+	  /* If the application already had unacknowledged data, we
+	     make sure that the application does not send (i.e.,
+	     retransmit) out more than it previously sent out. */
+	  uip_slen = uip_connr->len;
+	}
+      } else {
+	uip_connr->len = 0;
+      }
+      uip_connr->nrtx = 0;
+    apprexmit:
+      uip_appdata = uip_sappdata;
+      
+      /* If the application has data to be sent, or if the incoming
+         packet had new data in it, we must send out a packet. */
+      if(uip_slen > 0 && uip_connr->len > 0) {
+	/* Add the length of the IP and TCP headers. */
+	uip_len = uip_connr->len + UIP_TCPIP_HLEN;
+	/* We always set the ACK flag in response packets. */
+	BUF->flags = TCP_ACK | TCP_PSH;
+	/* Send the packet. */
+	goto tcp_send_noopts;
+      }
+      /* If there is no data to send, just send out a pure ACK if
+	 there is newdata. */
+      if(uip_flags & UIP_NEWDATA) {
+	uip_len = UIP_TCPIP_HLEN;
+	BUF->flags = TCP_ACK;
+	goto tcp_send_noopts;
+      }
+    }
+    goto drop;
+  case LAST_ACK:
+    /* We can close this connection if the peer has acknowledged our
+       FIN. This is indicated by the UIP_ACKDATA flag. */     
+    if(uip_flags & UIP_ACKDATA) {
+      uip_connr->tcpstateflags = CLOSED;
+      uip_flags = UIP_CLOSE;
+      UIP_APPCALL();
+    }
+    break;
+    
+  case FIN_WAIT_1:
+    /* The application has closed the connection, but the remote host
+       hasn't closed its end yet. Thus we do nothing but wait for a
+       FIN from the other side. */
+    if(uip_len > 0) {
+      uip_add_rcv_nxt(uip_len);
+    }
+    if(BUF->flags & TCP_FIN) {
+      if(uip_flags & UIP_ACKDATA) {
+	uip_connr->tcpstateflags = TIME_WAIT;
+	uip_connr->timer = 0;
+	uip_connr->len = 0;
+      } else {
+	uip_connr->tcpstateflags = CLOSING;
+      }
+      uip_add_rcv_nxt(1);
+      uip_flags = UIP_CLOSE;
+      UIP_APPCALL();
+      goto tcp_send_ack;
+    } else if(uip_flags & UIP_ACKDATA) {
+      uip_connr->tcpstateflags = FIN_WAIT_2;
+      uip_connr->len = 0;
+      goto drop;
+    }
+    if(uip_len > 0) {
+      goto tcp_send_ack;
+    }
+    goto drop;
+      
+  case FIN_WAIT_2:
+    if(uip_len > 0) {
+      uip_add_rcv_nxt(uip_len);
+    }
+    if(BUF->flags & TCP_FIN) {
+      uip_connr->tcpstateflags = TIME_WAIT;
+      uip_connr->timer = 0;
+      uip_add_rcv_nxt(1);
+      uip_flags = UIP_CLOSE;
+      UIP_APPCALL();
+      goto tcp_send_ack;
+    }
+    if(uip_len > 0) {
+      goto tcp_send_ack;
+    }
+    goto drop;
+
+  case TIME_WAIT:
+    goto tcp_send_ack;
+    
+  case CLOSING:
+    if(uip_flags & UIP_ACKDATA) {
+      uip_connr->tcpstateflags = TIME_WAIT;
+      uip_connr->timer = 0;
+    }
+  }  
+  goto drop;
+  
+
+  /* We jump here when we are ready to send the packet, and just want
+     to set the appropriate TCP sequence numbers in the TCP header. */
+ tcp_send_ack:
+  BUF->flags = TCP_ACK;
+ tcp_send_nodata:
+  uip_len = 40;
+ tcp_send_noopts:
+  BUF->tcpoffset = 5 << 4;
+ tcp_send:
+  /* We're done with the input processing. We are now ready to send a
+     reply. Our job is to fill in all the fields of the TCP and IP
+     headers before calculating the checksum and finally send the
+     packet. */
+  BUF->ackno[0] = uip_connr->rcv_nxt[0];
+  BUF->ackno[1] = uip_connr->rcv_nxt[1];
+  BUF->ackno[2] = uip_connr->rcv_nxt[2];
+  BUF->ackno[3] = uip_connr->rcv_nxt[3];
+  
+  BUF->seqno[0] = uip_connr->snd_nxt[0];
+  BUF->seqno[1] = uip_connr->snd_nxt[1];
+  BUF->seqno[2] = uip_connr->snd_nxt[2];
+  BUF->seqno[3] = uip_connr->snd_nxt[3];
+
+  BUF->proto = UIP_PROTO_TCP;
+  
+  BUF->srcport  = uip_connr->lport;
+  BUF->destport = uip_connr->rport;
+
+  BUF->srcipaddr[0] = uip_hostaddr[0];
+  BUF->srcipaddr[1] = uip_hostaddr[1];
+  BUF->destipaddr[0] = uip_connr->ripaddr[0];
+  BUF->destipaddr[1] = uip_connr->ripaddr[1];
+ 
+
+  if(uip_connr->tcpstateflags & UIP_STOPPED) {
+    /* If the connection has issued uip_stop(), we advertise a zero
+       window so that the remote host will stop sending data. */
+    BUF->wnd[0] = BUF->wnd[1] = 0;
+  } else {
+    BUF->wnd[0] = ((UIP_RECEIVE_WINDOW) >> 8);
+    BUF->wnd[1] = ((UIP_RECEIVE_WINDOW) & 0xff); 
+  }
+
+ tcp_send_noconn:
+
+  BUF->len[0] = (uip_len >> 8);
+  BUF->len[1] = (uip_len & 0xff);
+
+  /* Calculate TCP checksum. */
+  BUF->tcpchksum = 0;
+  BUF->tcpchksum = ~(uip_tcpchksum());
+  
+ ip_send_nolen:
+
+  BUF->vhl = 0x45;
+  BUF->tos = 0;
+  BUF->ipoffset[0] = BUF->ipoffset[1] = 0;
+  BUF->ttl  = UIP_TTL;
+  ++ipid;
+  BUF->ipid[0] = ipid >> 8;
+  BUF->ipid[1] = ipid & 0xff;
+  
+  /* Calculate IP checksum. */
+  BUF->ipchksum = 0;
+  BUF->ipchksum = ~(uip_ipchksum());
+
+  UIP_STAT(++uip_stat.tcp.sent);
+ send:
+  UIP_STAT(++uip_stat.ip.sent);
+  /* Return and let the caller do the actual transmission. */
+  return;
+ drop:
+  uip_len = 0;
+  return;
+}
+/*-----------------------------------------------------------------------------------*/
+u16_t
+htons(u16_t val)
+{
+  return HTONS(val);
+}
+/*-----------------------------------------------------------------------------------*/
+/** @} */
diff --git a/src/proto/uip/uip.h b/src/proto/uip/uip.h
new file mode 100644
index 00000000..60dd7351
--- /dev/null
+++ b/src/proto/uip/uip.h
@@ -0,0 +1,1060 @@
+/**
+ * \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.
+ *
+ * $Id$
+ *
+ */
+
+#ifndef __UIP_H__
+#define __UIP_H__
+
+#include "uipopt.h"
+
+/*-----------------------------------------------------------------------------------*/
+/* 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.
+ *
+ * \param addr A pointer to a 4-byte representation of the IP address.
+ *
+ * \hideinitializer
+ */
+#define uip_sethostaddr(addr) do { uip_hostaddr[0] = addr[0]; \
+                              uip_hostaddr[1] = addr[1]; } while(0)
+
+/**
+ * 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.
+ *
+ * \param addr A pointer to a 4-byte array that will be filled in with
+ * the currently configured IP address.
+ *
+ * \hideinitializer
+ */
+#define uip_gethostaddr(addr) do { addr[0] = uip_hostaddr[0]; \
+                              addr[1] = uip_hostaddr[1]; } while(0)
+
+/** @} */
+
+/**
+ * \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);
+
+/** @} */
+
+/**
+ * \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)
+
+/**
+ * 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)
+
+#if UIP_UDP
+/**
+ * Periodic processing for a UDP connection identified by its number.
+ *
+ * This function is essentially the same as uip_prerioic(), 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);
+    hwsend(&uip_buf[UIP_LLH_LEN], 40);
+    hwsend(uip_appdata, uip_len - 40 - 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 convertion using HTONS() or htons() is necessary.
+ *
+ \code
+ u16_t ipaddr[2];
+
+ uip_ipaddr(ipaddr, 192,168,1,2);
+ uip_connect(ipaddr, HTONS(80)); 
+ \endcode
+ * 
+ * \param ripaddr A pointer to a 4-byte array representing 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(u16_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
+ */
+#define uip_send(data, len) do { uip_sappdata = (data); uip_slen = (len);} while(0)   
+
+/**
+ * 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
+ */
+#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 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.
+ *
+ * \param ripaddr A pointer to a 4-byte structure representing 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(u16_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
+
+/**
+ * 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_slen = (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.
+ */
+ 
+/**
+ * Pack an IP address into a 4-byte array which is used by uIP to
+ * represent IP addresses.
+ *
+ * Example:
+ \code
+ u16_t ipaddr[2];
+
+ uip_ipaddr(&ipaddr, 192,168,1,2); 
+ \endcode
+ *
+ * \param addr A pointer to a 4-byte array that will be filled in with
+ * the IP addres.
+ * \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 { \
+                     (addr)[0] = HTONS(((addr0) << 8) | (addr1)); \
+                     (addr)[1] = HTONS(((addr2) << 8) | (addr3)); \
+                  } while(0)
+
+/**
+ * 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 BYTE_ORDER == BIG_ENDIAN
+#      define HTONS(n) (n)
+#   else /* BYTE_ORDER == BIG_ENDIAN */
+#      define HTONS(n) ((((u16_t)((n) & 0xff)) << 8) | (((n) & 0xff00) >> 8))
+#   endif /* BYTE_ORDER == BIG_ENDIAN */
+#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 */
+
+/** @} */
+
+/**
+ * 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 volatile u8_t *uip_appdata;
+extern volatile u8_t *uip_sappdata; 
+
+#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 volatile u8_t *uip_urgdata; 
+#endif /* UIP_URGDATA > 0 */
+
+
+/* u[8|16]_t uip_len:
+ *
+ * When the application is called, uip_len contains the length of any
+ * new data that has been received from the remote host. The
+ * application should set this variable to the size of any data that
+ * the application wishes to send. When the network device driver
+ * output function is called, uip_len should contain the length of the
+ * outgoing packet.
+ */
+extern volatile u16_t uip_len, uip_slen;
+
+#if UIP_URGDATA > 0 
+extern volatile u8_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 size of this field is
+ * configured in the "uipopt.h" header file.
+ */
+struct uip_conn {
+  u16_t ripaddr[2];   /**< 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. */
+  u8_t appstate[UIP_APPSTATE_SIZE];  
+};
+
+
+/* Pointer to the current 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 volatile u8_t uip_acc32[4];
+
+/** @} */
+
+
+#if UIP_UDP
+/**
+ * Representation of a uIP UDP connection.
+ */
+struct uip_udp_conn {
+  u16_t ripaddr[2];   /**< 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. */
+};
+
+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. */
+};
+
+/**
+ * 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 volatile u8_t uip_flags;
+
+/* The following flags may be set in the global variable uip_flags
+   before calling the application callback. The UIP_ACKDATA and
+   UIP_NEWDATA 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 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. */
+
+#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. */
+#if UIP_UDP
+#define UIP_UDP_TIMER 3
+#endif /* UIP_UDP */
+
+/* The TCP states used in the uip_conn->tcpstateflags. */
+#define CLOSED      0
+#define SYN_RCVD    1
+#define SYN_SENT    2
+#define ESTABLISHED 3
+#define FIN_WAIT_1  4
+#define FIN_WAIT_2  5
+#define CLOSING     6
+#define TIME_WAIT   7
+#define LAST_ACK    8
+#define TS_MASK     15
+  
+#define UIP_STOPPED      16
+
+#define UIP_TCPIP_HLEN 40
+
+/* The TCP and IP headers. */
+typedef struct {
+  /* IP header. */
+  u8_t vhl,
+    tos,          
+    len[2],       
+    ipid[2],        
+    ipoffset[2],  
+    ttl,          
+    proto;     
+  u16_t ipchksum;
+  u16_t srcipaddr[2], 
+    destipaddr[2];
+  
+  /* 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];
+} uip_tcpip_hdr;
+
+/* The ICMP and IP headers. */
+typedef struct {
+  /* IP header. */
+  u8_t vhl,
+    tos,          
+    len[2],       
+    ipid[2],        
+    ipoffset[2],  
+    ttl,          
+    proto;     
+  u16_t ipchksum;
+  u16_t srcipaddr[2], 
+    destipaddr[2];
+  /* ICMP (echo) header. */
+  u8_t type, icode;
+  u16_t icmpchksum;
+  u16_t id, seqno;  
+} uip_icmpip_hdr;
+
+
+/* The UDP and IP headers. */
+typedef struct {
+  /* IP header. */
+  u8_t vhl,
+    tos,          
+    len[2],       
+    ipid[2],        
+    ipoffset[2],  
+    ttl,          
+    proto;     
+  u16_t ipchksum;
+  u16_t srcipaddr[2], 
+    destipaddr[2];
+  
+  /* UDP header. */
+  u16_t srcport,
+    destport;
+  u16_t udplen;
+  u16_t udpchksum;
+} uip_udpip_hdr;
+
+#define UIP_PROTO_ICMP  1
+#define UIP_PROTO_TCP   6
+#define UIP_PROTO_UDP   17
+
+#if UIP_FIXEDADDR
+extern const u16_t uip_hostaddr[2];
+#else /* UIP_FIXEDADDR */
+extern u16_t uip_hostaddr[2];
+#endif /* UIP_FIXEDADDR */
+
+#endif /* __UIP_H__ */
+
+
+/** @} */
+
diff --git a/src/proto/uip/uip_arch.h b/src/proto/uip/uip_arch.h
new file mode 100644
index 00000000..db71aeb2
--- /dev/null
+++ b/src/proto/uip/uip_arch.h
@@ -0,0 +1,130 @@
+/**
+ * \defgroup uiparch Architecture specific uIP functions
+ * @{
+ *
+ * The functions in the architecture specific module implement the IP
+ * check sum and 32-bit additions.
+ *
+ * The IP checksum calculation is the most computationally expensive
+ * operation in the TCP/IP stack and it therefore pays off to
+ * implement this in efficient assembler. The purpose of the uip-arch
+ * module is to let the checksum functions to be implemented in
+ * architecture specific assembler.
+ *
+ */
+
+/**
+ * \file
+ * Declarations of architecture specific functions.
+ * \author Adam Dunkels <adam@dunkels.com>
+ */
+
+/*
+ * Copyright (c) 2001, 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.
+ *
+ * $Id$
+ *
+ */
+
+#ifndef __UIP_ARCH_H__
+#define __UIP_ARCH_H__
+
+#include "uip.h"
+
+/**
+ * Carry out a 32-bit addition.
+ *
+ * Because not all architectures for which uIP is intended has native
+ * 32-bit arithmetic, uIP uses an external C function for doing the
+ * required 32-bit additions in the TCP protocol processing. This
+ * function should add the two arguments and place the result in the
+ * global variable uip_acc32.
+ *
+ * \note The 32-bit integer pointed to by the op32 parameter and the
+ * result in the uip_acc32 variable are in network byte order (big
+ * endian).
+ *
+ * \param op32 A pointer to a 4-byte array representing a 32-bit
+ * integer in network byte order (big endian).
+ *
+ * \param op16 A 16-bit integer in host byte order.
+ */
+void uip_add32(u8_t *op32, u16_t op16);
+
+/**
+ * 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.
+ *
+ * \note This function is not called in the current version of uIP,
+ * but future versions might make use of it.
+ *
+ * \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.
+ *
+ * \note The uip_appdata pointer that points to the packet data may
+ * point anywhere in memory, so it is not possible to simply calculate
+ * the Internet checksum of the contents of the uip_buf buffer.
+ *
+ * \return The TCP checksum of the TCP segment in uip_buf and pointed
+ * to by uip_appdata.
+ */
+u16_t uip_tcpchksum(void);
+
+/** @} */
+
+#endif /* __UIP_ARCH_H__ */
diff --git a/src/proto/uip/uipopt.h b/src/proto/uip/uipopt.h
new file mode 100644
index 00000000..61117c30
--- /dev/null
+++ b/src/proto/uip/uipopt.h
@@ -0,0 +1,558 @@
+/**
+ * \defgroup uipopt Configuration options for uIP
+ * @{
+ *
+ * uIP is configured using the per-project configuration file
+ * "uipopt.h". This file contains all compile-time options for uIP and
+ * should be tweaked to match each specific project. The uIP
+ * distribution contains a documented example "uipopt.h" that can be
+ * copied and modified for each project.
+ */
+
+/**
+ * \file
+ * Configuration options for uIP.
+ * \author Adam Dunkels <adam@dunkels.com>
+ *
+ * This file is used for tweaking various configuration options for
+ * uIP. You should make a copy of this file into one of your project's
+ * directories instead of editing this example "uipopt.h" file that
+ * comes with the uIP distribution.
+ */
+
+/*
+ * 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.
+ *
+ * $Id$
+ *
+ */
+
+#ifndef __UIPOPT_H__
+#define __UIPOPT_H__
+
+/*------------------------------------------------------------------------------*/
+/**
+ * \defgroup uipopttypedef uIP type definitions
+ * @{
+ */
+
+/**
+ * The 8-bit unsigned data type.
+ *
+ * This may have to be tweaked for your particular compiler. "unsigned
+ * char" works for most compilers.
+ */
+typedef unsigned char u8_t;
+
+/**
+ * The 16-bit unsigned data type.
+ *
+ * This may have to be tweaked for your particular compiler. "unsigned
+ * short" works for most compilers.
+ */
+typedef unsigned short u16_t;
+
+/**
+ * The statistics data type.
+ *
+ * This datatype determines how high the statistics counters are able
+ * to count.
+ */
+typedef unsigned short uip_stats_t;
+
+/** @} */
+
+/*------------------------------------------------------------------------------*/
+
+/**
+ * \defgroup uipoptstaticconf Static configuration options
+ * @{
+ *
+ * These configuration options can be used for setting the IP address
+ * settings statically, but only if UIP_FIXEDADDR is set to 1. The
+ * configuration options for a specific node includes IP address,
+ * netmask and default router as well as the Ethernet address. The
+ * netmask, default router and Ethernet address are appliciable only
+ * if uIP should be run over Ethernet.
+ *
+ * All of these should be changed to suit your project.
+*/
+
+/**
+ * Determines if uIP should use a fixed IP address or not.
+ *
+ * If uIP should use a fixed IP address, the settings are set in the
+ * uipopt.h file. If not, the macros uip_sethostaddr(),
+ * uip_setdraddr() and uip_setnetmask() should be used instead.
+ *
+ * \hideinitializer
+ */
+#define UIP_FIXEDADDR    1
+
+/**
+ * Ping IP address asignment.
+ *
+ * uIP uses a "ping" packets for setting its own IP address if this
+ * option is set. If so, uIP will start with an empty IP address and
+ * the destination IP address of the first incoming "ping" (ICMP echo)
+ * packet will be used for setting the hosts IP address.
+ *
+ * \note This works only if UIP_FIXEDADDR is 0.
+ *
+ * \hideinitializer
+ */
+#define UIP_PINGADDRCONF 0
+
+#define UIP_IPADDR0     192 /**< The first octet of the IP address of
+			       this uIP node, if UIP_FIXEDADDR is
+			       1. \hideinitializer */
+#define UIP_IPADDR1     168 /**< The second octet of the IP address of
+			       this uIP node, if UIP_FIXEDADDR is
+			       1. \hideinitializer */
+#define UIP_IPADDR2     0   /**< The third octet of the IP address of
+			       this uIP node, if UIP_FIXEDADDR is
+			       1. \hideinitializer */
+#define UIP_IPADDR3     2   /**< The fourth octet of the IP address of
+			       this uIP node, if UIP_FIXEDADDR is
+			       1. \hideinitializer */
+
+#define UIP_NETMASK0    255 /**< The first octet of the netmask of
+			       this uIP node, if UIP_FIXEDADDR is
+			       1. \hideinitializer */
+#define UIP_NETMASK1    255 /**< The second octet of the netmask of
+			       this uIP node, if UIP_FIXEDADDR is
+			       1. \hideinitializer */
+#define UIP_NETMASK2    255 /**< The third octet of the netmask of
+			       this uIP node, if UIP_FIXEDADDR is
+			       1. \hideinitializer */
+#define UIP_NETMASK3    0   /**< The fourth octet of the netmask of
+			       this uIP node, if UIP_FIXEDADDR is
+			       1. \hideinitializer */
+
+#define UIP_DRIPADDR0   192 /**< The first octet of the IP address of
+			       the default router, if UIP_FIXEDADDR is
+			       1. \hideinitializer */
+#define UIP_DRIPADDR1   168 /**< The second octet of the IP address of
+			       the default router, if UIP_FIXEDADDR is
+			       1. \hideinitializer */
+#define UIP_DRIPADDR2   0   /**< The third octet of the IP address of
+			       the default router, if UIP_FIXEDADDR is
+			       1. \hideinitializer */
+#define UIP_DRIPADDR3   1   /**< The fourth octet of the IP address of
+			       the default router, if UIP_FIXEDADDR is
+			       1. \hideinitializer */
+
+/**
+ * Specifies if the uIP ARP module should be compiled with a fixed
+ * Ethernet MAC address or not.
+ *
+ * If this configuration option is 0, the macro uip_setethaddr() can
+ * be used to specify the Ethernet address at run-time.
+ *
+ * \hideinitializer
+ */
+#define UIP_FIXEDETHADDR 0
+
+#define UIP_ETHADDR0    0x00  /**< The first octet of the Ethernet
+				 address if UIP_FIXEDETHADDR is
+				 1. \hideinitializer */
+#define UIP_ETHADDR1    0xbd  /**< The second octet of the Ethernet
+				 address if UIP_FIXEDETHADDR is
+				 1. \hideinitializer */
+#define UIP_ETHADDR2    0x3b  /**< The third octet of the Ethernet
+				 address if UIP_FIXEDETHADDR is
+				 1. \hideinitializer */
+#define UIP_ETHADDR3    0x33  /**< The fourth octet of the Ethernet
+				 address if UIP_FIXEDETHADDR is
+				 1. \hideinitializer */
+#define UIP_ETHADDR4    0x05  /**< The fifth octet of the Ethernet
+				 address if UIP_FIXEDETHADDR is
+				 1. \hideinitializer */
+#define UIP_ETHADDR5    0x71  /**< The sixth octet of the Ethernet
+				 address if UIP_FIXEDETHADDR is
+				 1. \hideinitializer */
+
+/** @} */
+/*------------------------------------------------------------------------------*/
+/**
+ * \defgroup uipoptip IP configuration options
+ * @{
+ *
+ */
+/**
+ * The IP TTL (time to live) of IP packets sent by uIP.
+ *
+ * This should normally not be changed.
+ */
+#define UIP_TTL         255
+
+/**
+ * Turn on support for IP packet reassembly.
+ *
+ * uIP supports reassembly of fragmented IP packets. This features
+ * requires an additonal amount of RAM to hold the reassembly buffer
+ * and the reassembly code size is approximately 700 bytes.  The
+ * reassembly buffer is of the same size as the uip_buf buffer
+ * (configured by UIP_BUFSIZE).
+ *
+ * \note IP packet reassembly is not heavily tested.
+ *
+ * \hideinitializer
+ */
+#define UIP_REASSEMBLY 0
+
+/**
+ * The maximum time an IP fragment should wait in the reassembly
+ * buffer before it is dropped.
+ *
+ */
+#define UIP_REASS_MAXAGE 40
+
+/** @} */
+
+/*------------------------------------------------------------------------------*/
+/**
+ * \defgroup uipoptudp UDP configuration options
+ * @{
+ *
+ * \note The UDP support in uIP is still not entirely complete; there
+ * is no support for sending or receiving broadcast or multicast
+ * packets, but it works well enough to support a number of vital
+ * applications such as DNS queries, though
+ */
+
+/**
+ * Toggles wether UDP support should be compiled in or not.
+ *
+ * \hideinitializer
+ */
+#define UIP_UDP           1
+
+/**
+ * Toggles if UDP checksums should be used or not.
+ *
+ * \note Support for UDP checksums is currently not included in uIP,
+ * so this option has no function.
+ *
+ * \hideinitializer
+ */
+#define UIP_UDP_CHECKSUMS 0
+
+/**
+ * The maximum amount of concurrent UDP connections.
+ *
+ * \hideinitializer
+ */
+#define UIP_UDP_CONNS    10
+
+/**
+ * The name of the function that should be called when UDP datagrams arrive.
+ *
+ * \hideinitializer
+ */
+#define UIP_UDP_APPCALL  udp_appcall
+
+/** @} */
+/*------------------------------------------------------------------------------*/
+/**
+ * \defgroup uipopttcp TCP configuration options
+ * @{
+ */
+
+/**
+ * Determines if support for opening connections from uIP should be
+ * compiled in.
+ *
+ * If the applications that are running on top of uIP for this project
+ * do not need to open outgoing TCP connections, this configration
+ * option can be turned off to reduce the code size of uIP.
+ *
+ * \hideinitializer
+ */
+#define UIP_ACTIVE_OPEN 1
+
+/**
+ * The maximum number of simultaneously open TCP connections.
+ *
+ * Since the TCP connections are statically allocated, turning this
+ * configuration knob down results in less RAM used. Each TCP
+ * connection requires approximatly 30 bytes of memory.
+ *
+ * \hideinitializer
+ */
+#define UIP_CONNS       10
+
+/**
+ * The maximum number of simultaneously listening TCP ports.
+ *
+ * Each listening TCP port requires 2 bytes of memory.
+ *
+ * \hideinitializer
+ */
+#define UIP_LISTENPORTS 10
+
+/**
+ * The size of the advertised receiver's window.
+ *
+ * Should be set low (i.e., to the size of the uip_buf buffer) is the
+ * application is slow to process incoming data, or high (32768 bytes)
+ * if the application processes data quickly.
+ *
+ * \hideinitializer
+ */
+#define UIP_RECEIVE_WINDOW   32768
+
+/**
+ * Determines if support for TCP urgent data notification should be
+ * compiled in.
+ *
+ * Urgent data (out-of-band data) is a rarely used TCP feature that
+ * very seldom would be required.
+ *
+ * \hideinitializer
+ */
+#define UIP_URGDATA      1
+
+/**
+ * The initial retransmission timeout counted in timer pulses.
+ *
+ * This should not be changed.
+ */
+#define UIP_RTO         3
+
+/**
+ * The maximum number of times a segment should be retransmitted
+ * before the connection should be aborted.
+ *
+ * This should not be changed.
+ */
+#define UIP_MAXRTX      8
+
+/**
+ * The maximum number of times a SYN segment should be retransmitted
+ * before a connection request should be deemed to have been
+ * unsuccessful.
+ *
+ * This should not need to be changed.
+ */
+#define UIP_MAXSYNRTX      3
+
+/**
+ * The TCP maximum segment size.
+ *
+ * This is should not be to set to more than UIP_BUFSIZE - UIP_LLH_LEN - 40.
+ */
+#define UIP_TCP_MSS     (UIP_BUFSIZE - UIP_LLH_LEN - 40)
+
+/**
+ * How long a connection should stay in the TIME_WAIT state.
+ *
+ * This configiration option has no real implication, and it should be
+ * left untouched.
+ */ 
+#define UIP_TIME_WAIT_TIMEOUT 120
+
+
+/** @} */
+/*------------------------------------------------------------------------------*/
+/**
+ * \defgroup uipoptarp ARP configuration options
+ * @{
+ */
+
+/**
+ * The size of the ARP table.
+ *
+ * This option should be set to a larger value if this uIP node will
+ * have many connections from the local network.
+ *
+ * \hideinitializer
+ */
+#define UIP_ARPTAB_SIZE 8
+
+/**
+ * The maxium age of ARP table entries measured in 10ths of seconds.
+ *
+ * An UIP_ARP_MAXAGE of 120 corresponds to 20 minutes (BSD
+ * default).
+ */
+#define UIP_ARP_MAXAGE 120
+
+/** @} */
+
+/*------------------------------------------------------------------------------*/
+
+/**
+ * \defgroup uipoptgeneral General configuration options
+ * @{
+ */
+
+/**
+ * The size of the uIP packet buffer.
+ *
+ * The uIP packet buffer should not be smaller than 60 bytes, and does
+ * not need to be larger than 1500 bytes. Lower size results in lower
+ * TCP throughput, larger size results in higher TCP throughput.
+ *
+ * \hideinitializer
+ */
+#define UIP_BUFSIZE     1500
+
+
+/**
+ * Determines if statistics support should be compiled in.
+ *
+ * The statistics is useful for debugging and to show the user.
+ *
+ * \hideinitializer
+ */
+#define UIP_STATISTICS  0
+
+/**
+ * Determines if logging of certain events should be compiled in.
+ *
+ * This is useful mostly for debugging. The function uip_log()
+ * must be implemented to suit the architecture of the project, if
+ * logging is turned on.
+ *
+ * \hideinitializer
+ */
+#define UIP_LOGGING     0
+
+/**
+ * Print out a uIP log message.
+ *
+ * This function must be implemented by the module that uses uIP, and
+ * is called by uIP whenever a log message is generated.
+ */
+void uip_log(char *msg);
+
+/**
+ * The link level header length.
+ *
+ * This is the offset into the uip_buf where the IP header can be
+ * found. For Ethernet, this should be set to 14. For SLIP, this
+ * should be set to 0.
+ *
+ * \hideinitializer
+ */
+#define UIP_LLH_LEN     14
+
+
+/** @} */
+/*------------------------------------------------------------------------------*/
+/**
+ * \defgroup uipoptcpu CPU architecture configuration
+ * @{
+ *
+ * The CPU architecture configuration is where the endianess of the
+ * CPU on which uIP is to be run is specified. Most CPUs today are
+ * little endian, and the most notable exception are the Motorolas
+ * which are big endian. The BYTE_ORDER macro should be changed to
+ * reflect the CPU architecture on which uIP is to be run.
+ */
+#ifndef LITTLE_ENDIAN
+#define LITTLE_ENDIAN  3412
+#endif /* LITTLE_ENDIAN */
+#ifndef BIG_ENDIAN
+#define BIG_ENDIAN     1234
+#endif /* BIGE_ENDIAN */
+
+/**
+ * The byte order of the CPU architecture on which uIP is to be run.
+ *
+ * This option can be either BIG_ENDIAN (Motorola byte order) or
+ * LITTLE_ENDIAN (Intel byte order).
+ *
+ * \hideinitializer
+ */
+#ifndef BYTE_ORDER
+#define BYTE_ORDER     LITTLE_ENDIAN
+#endif /* BYTE_ORDER */
+
+/** @} */
+/*------------------------------------------------------------------------------*/
+
+/**
+ * \defgroup uipoptapp Appication specific configurations
+ * @{
+ *
+ * An uIP application is implemented using a single application
+ * function that is called by uIP whenever a TCP/IP event occurs. The
+ * name of this function must be registered with uIP at compile time
+ * using the UIP_APPCALL definition.
+ *
+ * uIP applications can store the application state within the
+ * uip_conn structure by specifying the size of the application
+ * structure with the UIP_APPSTATE_SIZE macro.
+ *
+ * The file containing the definitions must be included in the
+ * uipopt.h file.
+ *
+ * The following example illustrates how this can look.
+ \code
+
+void httpd_appcall(void);
+#define UIP_APPCALL     httpd_appcall
+
+struct httpd_state {
+  u8_t state; 
+  u16_t count;
+  char *dataptr;
+  char *script;
+};
+#define UIP_APPSTATE_SIZE (sizeof(struct httpd_state))
+ \endcode
+ */
+
+/**
+ * \var #define UIP_APPCALL
+ *
+ * The name of the application function that uIP should call in
+ * response to TCP/IP events.
+ *
+ */
+
+/**
+ * \var #define UIP_APPSTATE_SIZE
+ *
+ * The size of the application state that is to be stored in the
+ * uip_conn structure.
+ */
+#define UIP_APPSTATE_SIZE 0
+/** @} */
+
+/* Include the header file for the application program that should be
+   used. If you don't use the example web server, you should change
+   this. */
+//#include "httpd.h"
+
+
+#endif /* __UIPOPT_H__ */