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Diffstat (limited to 'uip/uip/uip-split.c')
| -rw-r--r-- | uip/uip/uip-split.c | 136 |
1 files changed, 136 insertions, 0 deletions
diff --git a/uip/uip/uip-split.c b/uip/uip/uip-split.c new file mode 100644 index 0000000..a910ee6 --- /dev/null +++ b/uip/uip/uip-split.c @@ -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(); + } + +} +/*-----------------------------------------------------------------------------*/ |