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- /*
- * This file was originally taken from the FreeBSD project.
- *
- * Copyright (c) 2001 Charles Mott <cm@linktel.net>
- * Copyright (c) 2008 coresystems GmbH
- * All rights reserved.
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
- #include <common.h>
- #include <net.h>
- unsigned compute_ip_checksum(const void *vptr, unsigned nbytes)
- {
- int sum, oddbyte;
- const unsigned short *ptr = vptr;
- sum = 0;
- while (nbytes > 1) {
- sum += *ptr++;
- nbytes -= 2;
- }
- if (nbytes == 1) {
- oddbyte = 0;
- ((u8 *)&oddbyte)[0] = *(u8 *)ptr;
- ((u8 *)&oddbyte)[1] = 0;
- sum += oddbyte;
- }
- sum = (sum >> 16) + (sum & 0xffff);
- sum += (sum >> 16);
- sum = ~sum & 0xffff;
- return sum;
- }
- unsigned add_ip_checksums(unsigned offset, unsigned sum, unsigned new)
- {
- unsigned long checksum;
- sum = ~sum & 0xffff;
- new = ~new & 0xffff;
- if (offset & 1) {
- /*
- * byte-swap the sum if it came from an odd offset; since the
- * computation is endian independant this works.
- */
- new = ((new >> 8) & 0xff) | ((new << 8) & 0xff00);
- }
- checksum = sum + new;
- if (checksum > 0xffff)
- checksum -= 0xffff;
- return (~checksum) & 0xffff;
- }
- int ip_checksum_ok(const void *addr, unsigned nbytes)
- {
- return !(compute_ip_checksum(addr, nbytes) & 0xfffe);
- }
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