3 * Functions common to all TCP/IPv6 modules, such as the Internet checksum and the
4 * byte order functions.
9 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
10 * All rights reserved.
12 * Redistribution and use in source and binary forms, with or without modification,
13 * are permitted provided that the following conditions are met:
15 * 1. Redistributions of source code must retain the above copyright notice,
16 * this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright notice,
18 * this list of conditions and the following disclaimer in the documentation
19 * and/or other materials provided with the distribution.
20 * 3. The name of the author may not be used to endorse or promote products
21 * derived from this software without specific prior written permission.
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
24 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
25 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
26 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
27 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
28 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
29 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
30 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
31 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
34 * This file is part of the lwIP TCP/IP stack.
36 * Author: Adam Dunkels <adam@sics.se>
43 #include "lwip/inet.h"
47 * Sums up all 16 bit words in a memory portion. Also includes any odd byte.
48 * This function is used by the other checksum functions.
50 * For now, this is not optimized. Must be optimized for the particular processor
51 * arcitecture on which it is to run. Preferebly coded in assembler.
55 chksum(void *dataptr
, u16_t len
)
57 u16_t
*sdataptr
= dataptr
;
61 for(acc
= 0; len
> 1; len
-= 2) {
65 /* add up any odd byte */
67 acc
+= htons((u16_t
)(*(u8_t
*)dataptr
) << 8);
74 /* inet_chksum_pseudo:
76 * Calculates the pseudo Internet checksum used by TCP and UDP for a pbuf chain.
80 inet_chksum_pseudo(struct pbuf
*p
,
81 struct ip_addr
*src
, struct ip_addr
*dest
,
82 u8_t proto
, u32_t proto_len
)
90 for(q
= p
; q
!= NULL
; q
= q
->next
) {
91 acc
+= chksum(q
->payload
, q
->len
);
93 acc
= (acc
& 0xffff) + (acc
>> 16);
95 if (q
->len
% 2 != 0) {
96 swapped
= 1 - swapped
;
97 acc
= ((acc
& 0xff) << 8) | ((acc
& 0xff00) >> 8);
102 acc
= ((acc
& 0xff) << 8) | ((acc
& 0xff00) >> 8);
105 for(i
= 0; i
< 8; i
++) {
106 acc
+= ((u16_t
*)src
->addr
)[i
] & 0xffff;
107 acc
+= ((u16_t
*)dest
->addr
)[i
] & 0xffff;
109 acc
= (acc
& 0xffff) + (acc
>> 16);
112 acc
+= (u16_t
)htons((u16_t
)proto
);
113 acc
+= ((u16_t
*)&proto_len
)[0] & 0xffff;
114 acc
+= ((u16_t
*)&proto_len
)[1] & 0xffff;
117 acc
= (acc
& 0xffff) + (acc
>> 16);
119 return ~(acc
& 0xffff);
124 * Calculates the Internet checksum over a portion of memory. Used primarely for IP
129 inet_chksum(void *dataptr
, u16_t len
)
133 acc
= chksum(dataptr
, len
);
134 sum
= (acc
& 0xffff) + (acc
>> 16);
136 return ~(sum
& 0xffff);
140 inet_chksum_pbuf(struct pbuf
*p
)
148 for(q
= p
; q
!= NULL
; q
= q
->next
) {
149 acc
+= chksum(q
->payload
, q
->len
);
151 acc
= (acc
& 0xffff) + (acc
>> 16);
153 if (q
->len
% 2 != 0) {
154 swapped
= 1 - swapped
;
155 acc
= (acc
& 0xff << 8) | (acc
& 0xff00 >> 8);
160 acc
= ((acc
& 0xff) << 8) | ((acc
& 0xff00) >> 8);
162 return ~(acc
& 0xffff);