/* * 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 Contiki operating system. * * Author: Adam Dunkels <adam@sics.se> * */ #include <string.h> #include "net/ip/uip-split.h" #include "net/ip/uip.h" #include "net/ipv4/uip-fw.h" #include "net/ip/uip_arch.h" #include "net/ip/tcpip.h" #define BUF ((struct uip_tcpip_hdr *)&uip_buf[UIP_LLH_LEN]) #ifdef UIP_SPLIT_CONF_SIZE #define UIP_SPLIT_SIZE UIP_SPLIT_CONF_SIZE #else /* UIP_SPLIT_CONF_SIZE */ #define UIP_SPLIT_SIZE UIP_TCP_MSS #endif /* UIP_SPLIT_CONF_SIZE */ /*-----------------------------------------------------------------------------*/ void uip_split_output(void) { #if UIP_TCP uint16_t tcplen, len1, len2; /* We only split TCP segments that are larger than or equal to UIP_SPLIT_SIZE, which is configurable through UIP_SPLIT_CONF_SIZE. */ if(BUF->proto == UIP_PROTO_TCP && uip_len >= UIP_SPLIT_SIZE + UIP_TCPIP_HLEN) { 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 NETSTACK_CONF_WITH_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 /* NETSTACK_CONF_WITH_IPV6 */ BUF->len[0] = uip_len >> 8; BUF->len[1] = uip_len & 0xff; #endif /* NETSTACK_CONF_WITH_IPV6 */ /* Recalculate the TCP checksum. */ BUF->tcpchksum = 0; BUF->tcpchksum = ~(uip_tcpchksum()); #if !NETSTACK_CONF_WITH_IPV6 /* Recalculate the IP checksum. */ BUF->ipchksum = 0; BUF->ipchksum = ~(uip_ipchksum()); #endif /* NETSTACK_CONF_WITH_IPV6 */ /* Transmit the first packet. */ /* uip_fw_output();*/ #if NETSTACK_CONF_WITH_IPV6 tcpip_ipv6_output(); #else tcpip_output(); #endif /* NETSTACK_CONF_WITH_IPV6 */ /* 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 NETSTACK_CONF_WITH_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 /* NETSTACK_CONF_WITH_IPV6 */ BUF->len[0] = uip_len >> 8; BUF->len[1] = uip_len & 0xff; #endif /* NETSTACK_CONF_WITH_IPV6 */ /* uip_appdata += len1;*/ memcpy(uip_appdata, (uint8_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 !NETSTACK_CONF_WITH_IPV6 /* Recalculate the IP checksum. */ BUF->ipchksum = 0; BUF->ipchksum = ~(uip_ipchksum()); #endif /* NETSTACK_CONF_WITH_IPV6 */ /* Transmit the second packet. */ /* uip_fw_output();*/ #if NETSTACK_CONF_WITH_IPV6 tcpip_ipv6_output(); #else tcpip_output(); #endif /* NETSTACK_CONF_WITH_IPV6 */ return; } #endif /* UIP_TCP */ /* uip_fw_output();*/ #if NETSTACK_CONF_WITH_IPV6 tcpip_ipv6_output(); #else tcpip_output(); #endif /* NETSTACK_CONF_WITH_IPV6 */ } /*-----------------------------------------------------------------------------*/