diff options
Diffstat (limited to 'sys/netinet/in4_cksum.c')
| -rw-r--r-- | sys/netinet/in4_cksum.c | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/sys/netinet/in4_cksum.c b/sys/netinet/in4_cksum.c new file mode 100644 index 00000000000..171d5467420 --- /dev/null +++ b/sys/netinet/in4_cksum.c @@ -0,0 +1,217 @@ +/* $OpenBSD: in4_cksum.c,v 1.1 1999/12/08 06:50:19 itojun Exp $ */ + +/* $NetBSD: in_cksum.c,v 1.13 1996/10/13 02:03:03 christos Exp $ */ + +/* + * Copyright (C) 1999 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. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. 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 <sys/socket.h> +#include <net/route.h> +#include <netinet/in.h> +#include <netinet/in_systm.h> +#include <netinet/ip.h> +#include <netinet/ip_var.h> + +/* + * Checksum routine for Internet Protocol family headers (Portable Version). + * This is only for IPv4 pseudo header checksum. + * No need to clear non-pseudo-header fields in IPv4 header. + * len is for actual payload size, and does not include IPv4 header and + * skipped header chain (off + len should be equal to the whole packet). + * + * 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);} + +int +in4_cksum(m, nxt, off, len) + register struct mbuf *m; + u_int8_t nxt; + register int off, len; +{ + register u_int16_t *w; + register int sum = 0; + register int mlen = 0; + int byte_swapped = 0; + struct ipovly ipov; + + union { + u_int8_t c[2]; + u_int16_t s; + } s_util; + union { + u_int16_t s[2]; + u_int32_t l; + } l_util; + + /* pseudo header */ + if (off < sizeof(struct ipovly)) + panic("offset too short"); + bzero(&ipov, sizeof(ipov)); + ipov.ih_len = htons(len); + ipov.ih_pr = nxt; + ipov.ih_src = mtod(m, struct ip *)->ip_src; + ipov.ih_dst = mtod(m, struct ip *)->ip_dst; + w = (u_int16_t *)&ipov; + /* assumes sizeof(ipov) == 20 */ + 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]; + + /* skip unnecessary part */ + while (m && off > 0) { + if (m->m_len > off) + break; + off -= m->m_len; + m = m->m_next; + } + + for (;m && len; m = m->m_next) { + if (m->m_len == 0) + continue; + w = (u_int16_t *)(mtod(m, caddr_t) + off); + 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] = *(u_int8_t *)w; + sum += s_util.s; + w = (u_int16_t *)((u_int8_t *)w + 1); + mlen = m->m_len - off - 1; + len--; + } else + mlen = m->m_len - off; + off = 0; + if (len < mlen) + mlen = len; + len -= mlen; + /* + * Force to even boundary. + */ + if ((1 & (long) w) && (mlen > 0)) { + REDUCE; + sum <<= 8; + s_util.c[0] = *(u_int8_t *)w; + w = (u_int16_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) + continue; + REDUCE; + while ((mlen -= 2) >= 0) { + sum += *w++; + } + if (byte_swapped) { + REDUCE; + sum <<= 8; + byte_swapped = 0; + if (mlen == -1) { + s_util.c[1] = *(u_int8_t *)w; + sum += s_util.s; + mlen = 0; + } else + mlen = -1; + } else if (mlen == -1) + s_util.c[0] = *(u_int8_t *)w; + } + if (len) + printf("cksum4: out of data\n"); + 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); +} |