/* $OpenBSD: in4_cksum.c,v 1.2 2005/05/24 20:35:29 miod Exp $ */ /* $NetBSD: in4_cksum.c,v 1.8 2003/09/29 22:54:28 matt 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. 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 */ #if 0 #include __KERNEL_RCSID(0, "$NetBSD: in4_cksum.c,v 1.8 2003/09/29 22:54:28 matt Exp $"); #endif #include #include #include #include #include #include #include #include #ifdef CKSUMDEBUG int in4_cksum_md_debug(struct mbuf *m, u_int8_t nxt, int off, int len); #define in4_cksum in4_cksum_md_debug #include #undef in4_cksum #undef ADDCARRY #undef REDUCE #endif /* * Checksum routine for Internet Protocol family headers. * 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 implementation is VAX version. */ #define REDUCE {sum = (sum & 0xffff) + (sum >> 16);} #define ADDCARRY {if (sum > 0xffff) sum -= 0xffff;} #define ADVANCE(n) {w += n; mlen -= n;} #define SWAP {sum <<= 8;} /* depends on recent REDUCE */ #define Asm __asm __volatile #define ADDL Asm("addl2 (%2)+,%0" : "=r" (sum) : "0" (sum), "r" (w)) #define ADWC Asm("adwc (%2)+,%0" : "=r" (sum) : "0" (sum), "r" (w)) #define ADDC Asm("adwc $0,%0" : "=r" (sum) : "0" (sum)) #define UNSWAP Asm("rotl $8,%0,%0" : "=r" (sum) : "0" (sum)) #define ADDBYTE {sum += *w; SWAP; byte_swapped ^= 1;} #define ADDWORD {sum += *(u_short *)w;} int in4_cksum(struct mbuf *m, u_int8_t nxt, int off, int len) { u_int8_t *w; u_int32_t sum = 0; int mlen = 0; int byte_swapped = 0; #ifdef CKSUMDEBUG int debugrv = in4_cksum_md_debug(m, nxt, off, len); #endif if (nxt != 0) { #ifdef DIAGNOSTIC if (off < sizeof(struct ipovly)) panic("in4_cksum: offset too short"); if (m->m_len < sizeof(struct ip)) panic("in4_cksum: bad mbuf chain"); #endif __asm __volatile( "movzwl %3,%0;" /* mov len to sum */ "addb2 %4,%0;" /* add proto to sum */ "rotl $8,%0,%0;" /* htons, carry is preserved */ "adwc 12(%2),%0;" /* add src ip */ "adwc 16(%2),%0;" /* add dst ip */ "adwc $0,%0;" /* clean up carry */ : "=r" (sum) : "0" (sum), "r" (mtod(m, void *)), "r" (len), "r"(nxt)); } /* 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 ((mlen = m->m_len) == 0) continue; w = mtod(m, u_int8_t *); if (off) { w += off; mlen -= off; off = 0; } if (len < mlen) mlen = len; len -= mlen; if (mlen < 16) goto short_mbuf; /* * Ensure that we're aligned on a word boundary here so * that we can do 32 bit operations below. */ if ((3 & (u_long) w) != 0) { REDUCE; if ((1 & (u_long) w) != 0) { ADDBYTE; ADVANCE(1); } if ((2 & (u_long) w) != 0) { ADDWORD; ADVANCE(2); } } /* * Do as much of the checksum as possible 32 bits at at time. * In fact, this loop is unrolled to make overhead from * branches &c small. */ while ((mlen -= 32) >= 0) { /* * Add with carry 16 words and fold in the last carry * by adding a 0 with carry. */ ADDL; ADWC; ADWC; ADWC; ADWC; ADWC; ADWC; ADWC; ADDC; } mlen += 32; if (mlen >= 16) { ADDL; ADWC; ADWC; ADWC; ADDC; mlen -= 16; } short_mbuf: if (mlen >= 8) { ADDL; ADWC; ADDC; mlen -= 8; } if (mlen >= 4) { ADDL; ADDC; mlen -= 4; } if (mlen > 0) { REDUCE; if (mlen >= 2) { ADDWORD; ADVANCE(2); } if (mlen >= 1) { ADDBYTE; } } } if (len) printf("cksum4: out of data\n"); if (byte_swapped) { UNSWAP; } REDUCE; ADDCARRY; #ifdef CKSUMDEBUG if ((sum ^ 0xffff) != debugrv) printf("in4_cksum: rv != debugrv (rv %x debugrv %x)\n", (sum ^ 0xffff), debugrv); #endif return (sum ^ 0xffff); }