/* $OpenBSD: in6_cksum.c,v 1.18 2019/04/22 22:47:49 bluhm Exp $ */ /* $KAME: in6_cksum.c,v 1.10 2000/12/03 00:53:59 itojun Exp $ */ /* * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. * 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 project 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 PROJECT 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 PROJECT 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. */ /* * 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 */ #include <sys/param.h> #include <sys/mbuf.h> #include <sys/systm.h> #include <netinet/in.h> #include <netinet/ip6.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. */ #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x) #define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);} /* * m MUST contain a continuous IP6 header. * off is a offset where TCP/UDP/ICMP6 header starts. * len is a total length of a transport segment. * (e.g. TCP header + TCP payload) */ int in6_cksum(struct mbuf *m, uint8_t nxt, uint32_t off, uint32_t len) { uint16_t *w; int sum = 0; int mlen = 0; int byte_swapped = 0; struct ip6_hdr *ip6; union { uint16_t phs[4]; struct { uint32_t ph_len; uint8_t ph_zero[3]; uint8_t ph_nxt; } ph __packed; } uph; union { uint8_t c[2]; uint16_t s; } s_util; union { uint16_t s[2]; uint32_t l; } l_util; /* sanity check */ if (m->m_pkthdr.len < off + len) { panic("%s: mbuf len (%d) < off+len (%d+%d)", __func__, m->m_pkthdr.len, off, len); } /* Skip pseudo-header if nxt == 0. */ if (nxt == 0) goto skip_phdr; bzero(&uph, sizeof(uph)); /* * First create IP6 pseudo header and calculate a summary. */ ip6 = mtod(m, struct ip6_hdr *); w = (uint16_t *)&ip6->ip6_src; uph.ph.ph_len = htonl(len); uph.ph.ph_nxt = nxt; /* IPv6 source address */ sum += w[0]; if (!IN6_IS_SCOPE_EMBED(&ip6->ip6_src)) sum += w[1]; sum += w[2]; sum += w[3]; sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7]; /* IPv6 destination address */ sum += w[8]; if (!IN6_IS_SCOPE_EMBED(&ip6->ip6_dst)) sum += w[9]; sum += w[10]; sum += w[11]; sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15]; /* Payload length and upper layer identifier */ sum += uph.phs[0]; sum += uph.phs[1]; sum += uph.phs[2]; sum += uph.phs[3]; skip_phdr: /* * Secondly calculate a summary of the first mbuf excluding offset. */ while (m != NULL && off > 0) { if (m->m_len <= off) off -= m->m_len; else break; m = m->m_next; } if (m == NULL) { if (off) panic("%s: out of header, off %u", __func__, off); goto end; } w = (uint16_t *)(mtod(m, uint8_t *) + off); mlen = m->m_len - off; if (len < mlen) mlen = len; len -= mlen; /* * Force to even boundary. */ if ((1 & (long) w) && (mlen > 0)) { REDUCE; sum <<= 8; s_util.c[0] = *(uint8_t *)w; w = (uint16_t *)((uint8_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 next; REDUCE; while ((mlen -= 2) >= 0) { sum += *w++; } if (byte_swapped) { REDUCE; sum <<= 8; byte_swapped = 0; 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; next: m = m->m_next; /* * Lastly calculate a summary of the rest of mbufs. */ for (;m && len; m = m->m_next) { if (m->m_len == 0) continue; w = mtod(m, uint16_t *); if (mlen == -1) { /* * The first byte of this mbuf is the continuation * of a word spanning between this mbuf and the * last mbuf. * * s_util.c[0] is already saved when scanning previous * mbuf. */ s_util.c[1] = *(uint8_t *)w; sum += s_util.s; w = (uint16_t *)((uint8_t *)w + 1); mlen = m->m_len - 1; len--; } else mlen = m->m_len; if (len < mlen) mlen = len; len -= mlen; /* * Force to even boundary. */ if ((1 & (long) w) && (mlen > 0)) { REDUCE; sum <<= 8; s_util.c[0] = *(uint8_t *)w; w = (uint16_t *)((uint8_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) continue; REDUCE; while ((mlen -= 2) >= 0) { sum += *w++; } if (byte_swapped) { REDUCE; sum <<= 8; byte_swapped = 0; 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; } end: if (len) panic("%s: out of data, len %u", __func__, 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); }
