Diff: EMAC/uIP/uip/uip-split.c

Revision:

0:bf7b9fba3924

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/EMAC/uIP/uip/uip-split.c	Sun Mar 20 05:38:56 2011 +0000
@@ -0,0 +1,136 @@
+/*
+ * Copyright (c) 2004, Swedish Institute of Computer Science.
+ * 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. Neither the name of the Institute nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``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 INSTITUTE OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * This file is part of the uIP TCP/IP stack
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ * $Id: uip-split.c,v 1.2 2006/06/12 08:00:30 adam Exp $
+ */
+
+#include <string.h>
+
+#include "uip-split.h"
+#include "uip.h"
+#include "uip-fw.h"
+#include "uip_arch.h"
+
+
+
+#define BUF ((struct uip_tcpip_hdr *)&uip_buf[UIP_LLH_LEN])
+
+/*-----------------------------------------------------------------------------*/
+void
+uip_split_output(void)
+{
+  u16_t tcplen, len1, len2;
+
+  /* We only try to split maximum sized TCP segments. */
+  if(BUF->proto == UIP_PROTO_TCP &&
+     uip_len == UIP_BUFSIZE - UIP_LLH_LEN) {
+
+    tcplen = uip_len - UIP_TCPIP_HLEN;
+    /* Split the segment in two. If the original packet length was
+       odd, we make the second packet one byte larger. */
+    len1 = len2 = tcplen / 2;
+    if(len1 + len2 < tcplen) {
+      ++len2;
+    }
+
+    /* Create the first packet. This is done by altering the length
+       field of the IP header and updating the checksums. */
+    uip_len = len1 + UIP_TCPIP_HLEN;
+#if UIP_CONF_IPV6
+    /* For IPv6, the IP length field does not include the IPv6 IP header
+       length. */
+    BUF->len[0] = ((uip_len - UIP_IPH_LEN) >> 8);
+    BUF->len[1] = ((uip_len - UIP_IPH_LEN) & 0xff);
+#else /* UIP_CONF_IPV6 */
+    BUF->len[0] = uip_len >> 8;
+    BUF->len[1] = uip_len & 0xff;
+#endif /* UIP_CONF_IPV6 */
+    
+    /* Recalculate the TCP checksum. */
+    BUF->tcpchksum = 0;
+    BUF->tcpchksum = ~(uip_tcpchksum());
+
+#if !UIP_CONF_IPV6
+    /* Recalculate the IP checksum. */
+    BUF->ipchksum = 0;
+    BUF->ipchksum = ~(uip_ipchksum());
+#endif /* UIP_CONF_IPV6 */
+    
+    /* Transmit the first packet. */
+    /*    uip_fw_output();*/
+    tcpip_output();
+
+    /* Now, create the second packet. To do this, it is not enough to
+       just alter the length field, but we must also update the TCP
+       sequence number and point the uip_appdata to a new place in
+       memory. This place is detemined by the length of the first
+       packet (len1). */
+    uip_len = len2 + UIP_TCPIP_HLEN;
+#if UIP_CONF_IPV6
+    /* For IPv6, the IP length field does not include the IPv6 IP header
+       length. */
+    BUF->len[0] = ((uip_len - UIP_IPH_LEN) >> 8);
+    BUF->len[1] = ((uip_len - UIP_IPH_LEN) & 0xff);
+#else /* UIP_CONF_IPV6 */
+    BUF->len[0] = uip_len >> 8;
+    BUF->len[1] = uip_len & 0xff;
+#endif /* UIP_CONF_IPV6 */
+    
+    /*    uip_appdata += len1;*/
+    memcpy(uip_appdata, (u8_t *)uip_appdata + len1, len2);
+
+    uip_add32(BUF->seqno, len1);
+    BUF->seqno[0] = uip_acc32[0];
+    BUF->seqno[1] = uip_acc32[1];
+    BUF->seqno[2] = uip_acc32[2];
+    BUF->seqno[3] = uip_acc32[3];
+    
+    /* Recalculate the TCP checksum. */
+    BUF->tcpchksum = 0;
+    BUF->tcpchksum = ~(uip_tcpchksum());
+
+#if !UIP_CONF_IPV6
+    /* Recalculate the IP checksum. */
+    BUF->ipchksum = 0;
+    BUF->ipchksum = ~(uip_ipchksum());
+#endif /* UIP_CONF_IPV6 */
+
+    /* Transmit the second packet. */
+    /*    uip_fw_output();*/
+    tcpip_output();
+  } else {
+    /*    uip_fw_output();*/
+    tcpip_output();
+  }
+     
+}
+/*-----------------------------------------------------------------------------*/