projects / people / ms / u-boot.git / blame
| Commit | Line | Data |
|---|---|---|
| 9b0e35cb SG |
1 | /* |
| 2 | * This file was originally taken from the FreeBSD project. | |
| 3 | * | |
| 4 | * Copyright (c) 2001 Charles Mott <cm@linktel.net> | |
| 5 | * Copyright (c) 2008 coresystems GmbH | |
| 6 | * All rights reserved. | |
| 7 | * | |
| 8 | * SPDX-License-Identifier: BSD-2-Clause | |
| 9 | */ | |
| 10 | ||
| 11 | #include <common.h> | |
| 12 | #include <net.h> | |
| 13 | ||
| 14 | unsigned compute_ip_checksum(const void *vptr, unsigned nbytes) | |
| 15 | { | |
| 16 | int sum, oddbyte; | |
| 17 | const unsigned short *ptr = vptr; | |
| 18 | ||
| 19 | sum = 0; | |
| 20 | while (nbytes > 1) { | |
| 21 | sum += *ptr++; | |
| 22 | nbytes -= 2; | |
| 23 | } | |
| 24 | if (nbytes == 1) { | |
| 25 | oddbyte = 0; | |
| 26 | ((u8 *)&oddbyte)[0] = *(u8 *)ptr; | |
| 27 | ((u8 *)&oddbyte)[1] = 0; | |
| 28 | sum += oddbyte; | |
| 29 | } | |
| 30 | sum = (sum >> 16) + (sum & 0xffff); | |
| 31 | sum += (sum >> 16); | |
| 32 | sum = ~sum & 0xffff; | |
| 33 | ||
| 34 | return sum; | |
| 35 | } | |
| 36 | ||
| 37 | unsigned add_ip_checksums(unsigned offset, unsigned sum, unsigned new) | |
| 38 | { | |
| 39 | unsigned long checksum; | |
| 40 | ||
| 41 | sum = ~sum & 0xffff; | |
| 42 | new = ~new & 0xffff; | |
| 43 | if (offset & 1) { | |
| 44 | /* | |
| 45 | * byte-swap the sum if it came from an odd offset; since the | |
| 46 | * computation is endian independant this works. | |
| 47 | */ | |
| 48 | new = ((new >> 8) & 0xff) | ((new << 8) & 0xff00); | |
| 49 | } | |
| 50 | checksum = sum + new; | |
| 51 | if (checksum > 0xffff) | |
| 52 | checksum -= 0xffff; | |
| 53 | ||
| 54 | return (~checksum) & 0xffff; | |
| 55 | } | |
| 56 | ||
| 57 | int ip_checksum_ok(const void *addr, unsigned nbytes) | |
| 58 | { | |
| 59 | return !(compute_ip_checksum(addr, nbytes) & 0xfffe); | |
| 60 | } |