Added the new version for dummynet.

[ipfw.git] / dummynet2 / in_cksum.c

diff --git a/dummynet2/in_cksum.c b/dummynet2/in_cksum.c
new file mode 100644 (file)
index 0000000..8972cef
--- /dev/null
+++ b/dummynet2/in_cksum.c
@@ -0,0 +1,150 @@
+/*-
+ * 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.
+ * 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/cdefs.h>
+__FBSDID("$FreeBSD: src/sys/netinet/in_cksum.c,v 1.10 2007/10/07 20:44:22 silby Exp $");
+
+#include <sys/param.h>
+#include <sys/mbuf.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);}
+
+int
+in_cksum(struct mbuf *m, int len)
+{
+       register u_short *w;
+       register int sum = 0;
+       register int mlen = 0;
+       int byte_swapped = 0;
+
+       union {
+               char    c[2];
+               u_short s;
+       } s_util;
+       union {
+               u_short s[2];
+               long    l;
+       } l_util;
+
+       for (;m && len; m = m->m_next) {
+               if (m->m_len == 0)
+                       continue;
+               w = mtod(m, u_short *);
+               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] = *(char *)w;
+                       sum += s_util.s;
+                       w = (u_short *)((char *)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 defined(CONFIG_X86_64)
+               if ((1 & (long) w) && (mlen > 0)) {
+#else
+               if ((1 & (int) w) && (mlen > 0)) {
+#endif
+                       REDUCE;
+                       sum <<= 8;
+                       s_util.c[0] = *(u_char *)w;
+                       w = (u_short *)((char *)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] = *(char *)w;
+                               sum += s_util.s;
+                               mlen = 0;
+                       } else
+                               mlen = -1;
+               } else if (mlen == -1)
+                       s_util.c[0] = *(char *)w;
+       }
+       if (len)
+               printf("cksum: 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);
+}