| /* SPDX-License-Identifier: BSD-3-Clause */ |
| /* |
| * Copyright (c) 1988, 1992, 1993 |
| * The Regents of the University of California. 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 University 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 REGENTS 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 REGENTS 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. |
| * |
| * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93 |
| * in_cksum.c,v 1.2 1994/08/02 07:48:16 davidg Exp |
| */ |
| |
| #include "slirp.h" |
| |
| /* |
| * Checksum routine for Internet Protocol family headers (Portable Version). |
| * |
| * This routine is very heavily used in the network |
| * code and should be modified for each CPU to be as fast as possible. |
| * |
| * XXX Since we will never span more than 1 mbuf, we can optimise this |
| */ |
| |
| #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x) |
| #define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; \ |
| (void)ADDCARRY(sum);} |
| |
| int cksum(struct mbuf *m, int len) |
| { |
| register uint16_t *w; |
| register int sum = 0; |
| register int mlen = 0; |
| int byte_swapped = 0; |
| |
| union { |
| uint8_t c[2]; |
| uint16_t s; |
| } s_util; |
| union { |
| uint16_t s[2]; |
| uint32_t l; |
| } l_util; |
| |
| if (m->m_len == 0) |
| goto cont; |
| w = mtod(m, uint16_t *); |
| |
| mlen = m->m_len; |
| |
| if (len < mlen) |
| mlen = len; |
| len -= mlen; |
| /* |
| * Force to even boundary. |
| */ |
| if ((1 & (uintptr_t)w) && (mlen > 0)) { |
| REDUCE; |
| sum <<= 8; |
| s_util.c[0] = *(uint8_t *)w; |
| w = (uint16_t *)((int8_t *)w + 1); |
| mlen--; |
| byte_swapped = 1; |
| } |
| /* |
| * Unroll the loop to make overhead from |
| * branches &c small. |
| */ |
| while ((mlen -= 32) >= 0) { |
| sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; |
| sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; |
| sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11]; |
| sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; |
| w += 16; |
| } |
| mlen += 32; |
| while ((mlen -= 8) >= 0) { |
| sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3]; |
| w += 4; |
| } |
| mlen += 8; |
| if (mlen == 0 && byte_swapped == 0) |
| goto cont; |
| REDUCE; |
| while ((mlen -= 2) >= 0) { |
| sum += *w++; |
| } |
| |
| if (byte_swapped) { |
| REDUCE; |
| sum <<= 8; |
| if (mlen == -1) { |
| s_util.c[1] = *(uint8_t *)w; |
| sum += s_util.s; |
| mlen = 0; |
| } else |
| |
| mlen = -1; |
| } else if (mlen == -1) |
| s_util.c[0] = *(uint8_t *)w; |
| |
| cont: |
| if (len) { |
| DEBUG_ERROR("cksum: out of data"); |
| DEBUG_ERROR(" len = %d", len); |
| } |
| if (mlen == -1) { |
| /* The last mbuf has odd # of bytes. Follow the |
| standard (the odd byte may be shifted left by 8 bits |
| or not as determined by endian-ness of the machine) */ |
| s_util.c[1] = 0; |
| sum += s_util.s; |
| } |
| REDUCE; |
| return (~sum & 0xffff); |
| } |
| |
| int ip6_cksum(struct mbuf *m) |
| { |
| /* TODO: Optimize this by being able to pass the ip6_pseudohdr to cksum |
| * separately from the mbuf */ |
| struct ip6 save_ip, *ip = mtod(m, struct ip6 *); |
| struct ip6_pseudohdr *ih = mtod(m, struct ip6_pseudohdr *); |
| int sum; |
| |
| save_ip = *ip; |
| |
| ih->ih_src = save_ip.ip_src; |
| ih->ih_dst = save_ip.ip_dst; |
| ih->ih_pl = htonl((uint32_t)ntohs(save_ip.ip_pl)); |
| ih->ih_zero_hi = 0; |
| ih->ih_zero_lo = 0; |
| ih->ih_nh = save_ip.ip_nh; |
| |
| sum = cksum(m, ((int)sizeof(struct ip6_pseudohdr)) |
| + ntohl(ih->ih_pl)); |
| |
| *ip = save_ip; |
| |
| return sum; |
| } |