BSD 4.4 Lite Kernel Sources

1 files changed, 149 insertions, 0 deletions

diff --git a/sys/netinet/in_cksum.c b/sys/netinet/in_cksum.c
new file mode 100644
index 000000000000..c19a92008360
--- /dev/null
+++ b/sys/netinet/in_cksum.c
@@ -0,0 +1,149 @@
+/*
+ * 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>
+
+/*
+ * 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(m, len)
+	register struct mbuf *m;
+	register 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 ((1 & (int) w) && (mlen > 0)) {
+			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);
+}