[101] | 1 | /*
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| 2 | * Copyright (c) 2004, Swedish Institute of Computer Science.
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| 3 | * All rights reserved.
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| 4 | *
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| 5 | * Redistribution and use in source and binary forms, with or without
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| 6 | * modification, are permitted provided that the following conditions
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| 7 | * are met:
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| 8 | * 1. Redistributions of source code must retain the above copyright
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| 9 | * notice, this list of conditions and the following disclaimer.
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| 10 | * 2. Redistributions in binary form must reproduce the above copyright
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| 11 | * notice, this list of conditions and the following disclaimer in the
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| 12 | * documentation and/or other materials provided with the distribution.
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| 13 | * 3. Neither the name of the Institute nor the names of its contributors
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| 14 | * may be used to endorse or promote products derived from this software
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| 15 | * without specific prior written permission.
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| 16 | *
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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| 18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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| 19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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| 20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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| 21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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| 22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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| 23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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| 24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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| 25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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| 26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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| 27 | * SUCH DAMAGE.
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| 28 | *
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| 29 | * This file is part of the uIP TCP/IP stack
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| 30 | *
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| 31 | * Author: Adam Dunkels <adam@sics.se>
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| 32 | *
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| 33 | * $Id: uip-split.c 158 2016-02-20 13:43:32Z coas-nagasima $
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| 34 | */
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| 35 |
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| 36 | #include <string.h>
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| 37 |
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[158] | 38 | #include "net/ip/uip-split.h"
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| 39 | #include "net/ip/uip.h"
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| 40 | #include "net/ipv4/uip-fw.h"
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| 41 | #include "net/ip/uip_arch.h"
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[101] | 42 |
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| 43 |
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| 44 |
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| 45 | #define BUF ((struct uip_tcpip_hdr *)&uip_buf[UIP_LLH_LEN])
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| 46 |
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| 47 | /*-----------------------------------------------------------------------------*/
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| 48 | void
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| 49 | uip_split_output(void)
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| 50 | {
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[158] | 51 | uint16_t tcplen, len1, len2;
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[101] | 52 |
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| 53 | /* We only try to split maximum sized TCP segments. */
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| 54 | if(BUF->proto == UIP_PROTO_TCP &&
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| 55 | uip_len == UIP_BUFSIZE - UIP_LLH_LEN) {
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| 56 |
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| 57 | tcplen = uip_len - UIP_TCPIP_HLEN;
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| 58 | /* Split the segment in two. If the original packet length was
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| 59 | odd, we make the second packet one byte larger. */
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| 60 | len1 = len2 = tcplen / 2;
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| 61 | if(len1 + len2 < tcplen) {
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| 62 | ++len2;
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| 63 | }
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| 64 |
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| 65 | /* Create the first packet. This is done by altering the length
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| 66 | field of the IP header and updating the checksums. */
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| 67 | uip_len = len1 + UIP_TCPIP_HLEN;
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| 68 | #if UIP_CONF_IPV6
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| 69 | /* For IPv6, the IP length field does not include the IPv6 IP header
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| 70 | length. */
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| 71 | BUF->len[0] = ((uip_len - UIP_IPH_LEN) >> 8);
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| 72 | BUF->len[1] = ((uip_len - UIP_IPH_LEN) & 0xff);
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| 73 | #else /* UIP_CONF_IPV6 */
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| 74 | BUF->len[0] = uip_len >> 8;
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| 75 | BUF->len[1] = uip_len & 0xff;
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| 76 | #endif /* UIP_CONF_IPV6 */
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| 77 |
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| 78 | /* Recalculate the TCP checksum. */
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| 79 | BUF->tcpchksum = 0;
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| 80 | BUF->tcpchksum = ~(uip_tcpchksum());
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| 81 |
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| 82 | #if !UIP_CONF_IPV6
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| 83 | /* Recalculate the IP checksum. */
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| 84 | BUF->ipchksum = 0;
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| 85 | BUF->ipchksum = ~(uip_ipchksum());
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| 86 | #endif /* UIP_CONF_IPV6 */
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| 87 |
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| 88 | /* Transmit the first packet. */
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| 89 | /* uip_fw_output();*/
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| 90 | tcpip_output();
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| 91 |
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| 92 | /* Now, create the second packet. To do this, it is not enough to
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| 93 | just alter the length field, but we must also update the TCP
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| 94 | sequence number and point the uip_appdata to a new place in
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| 95 | memory. This place is detemined by the length of the first
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| 96 | packet (len1). */
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| 97 | uip_len = len2 + UIP_TCPIP_HLEN;
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| 98 | #if UIP_CONF_IPV6
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| 99 | /* For IPv6, the IP length field does not include the IPv6 IP header
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| 100 | length. */
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| 101 | BUF->len[0] = ((uip_len - UIP_IPH_LEN) >> 8);
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| 102 | BUF->len[1] = ((uip_len - UIP_IPH_LEN) & 0xff);
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| 103 | #else /* UIP_CONF_IPV6 */
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| 104 | BUF->len[0] = uip_len >> 8;
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| 105 | BUF->len[1] = uip_len & 0xff;
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| 106 | #endif /* UIP_CONF_IPV6 */
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| 107 |
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| 108 | /* uip_appdata += len1;*/
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[158] | 109 | memcpy(uip_appdata, (uint8_t *)uip_appdata + len1, len2);
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[101] | 110 |
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| 111 | uip_add32(BUF->seqno, len1);
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| 112 | BUF->seqno[0] = uip_acc32[0];
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| 113 | BUF->seqno[1] = uip_acc32[1];
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| 114 | BUF->seqno[2] = uip_acc32[2];
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| 115 | BUF->seqno[3] = uip_acc32[3];
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| 116 |
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| 117 | /* Recalculate the TCP checksum. */
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| 118 | BUF->tcpchksum = 0;
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| 119 | BUF->tcpchksum = ~(uip_tcpchksum());
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| 120 |
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| 121 | #if !UIP_CONF_IPV6
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| 122 | /* Recalculate the IP checksum. */
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| 123 | BUF->ipchksum = 0;
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| 124 | BUF->ipchksum = ~(uip_ipchksum());
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| 125 | #endif /* UIP_CONF_IPV6 */
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| 126 |
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| 127 | /* Transmit the second packet. */
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| 128 | /* uip_fw_output();*/
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| 129 | tcpip_output();
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| 130 | } else {
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| 131 | /* uip_fw_output();*/
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| 132 | tcpip_output();
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| 133 | }
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| 134 |
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| 135 | }
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| 136 | /*-----------------------------------------------------------------------------*/
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