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authorChris Johns <chrisj@rtems.org>2015-06-15 17:42:23 +1000
committerChris Johns <chrisj@rtems.org>2015-06-15 17:42:23 +1000
commit8440506ee8945ad57f5e20e9962084d67808eb22 (patch)
tree38f567b1c56846b88f5f0828bd244b05519998ba /freebsd/contrib/tcpdump/in_cksum.c
parentUpdate LibBSD doco. (diff)
downloadrtems-libbsd-8440506ee8945ad57f5e20e9962084d67808eb22.tar.bz2
Add tcpdump and libpcap.
- Update the file builder generator to handle generator specific cflags and includes. The tcpdump and libpcap have localised headers and need specific headers paths to see them. There are also module specific flags and these need to be passed to the lex and yacc generators. - Add the tcpdump support.
Diffstat (limited to 'freebsd/contrib/tcpdump/in_cksum.c')
-rw-r--r--freebsd/contrib/tcpdump/in_cksum.c202
1 files changed, 202 insertions, 0 deletions
diff --git a/freebsd/contrib/tcpdump/in_cksum.c b/freebsd/contrib/tcpdump/in_cksum.c
new file mode 100644
index 00000000..bfd6be98
--- /dev/null
+++ b/freebsd/contrib/tcpdump/in_cksum.c
@@ -0,0 +1,202 @@
+#include <machine/rtems-bsd-user-space.h>
+
+/* in_cksum.c
+ * 4.4-Lite-2 Internet checksum routine, modified to take a vector of
+ * pointers/lengths giving the pieces to be checksummed. Also using
+ * Tahoe/CGI version of ADDCARRY(x) macro instead of from portable version.
+ */
+
+/*
+ * 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
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <tcpdump-stdinc.h>
+
+#include "interface.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) {if ((x) > 65535) (x) -= 65535;}
+#define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);}
+
+u_int16_t
+in_cksum(const struct cksum_vec *vec, int veclen)
+{
+ register const u_int16_t *w;
+ register int sum = 0;
+ register int mlen = 0;
+ int byte_swapped = 0;
+
+ union {
+ u_int8_t c[2];
+ u_int16_t s;
+ } s_util;
+ union {
+ u_int16_t s[2];
+ u_int32_t l;
+ } l_util;
+
+ for (; veclen != 0; vec++, veclen--) {
+ if (vec->len == 0)
+ continue;
+ w = (const u_int16_t *)(void *)vec->ptr;
+ if (mlen == -1) {
+ /*
+ * The first byte of this chunk is the continuation
+ * of a word spanning between this chunk and the
+ * last chunk.
+ *
+ * s_util.c[0] is already saved when scanning previous
+ * chunk.
+ */
+ s_util.c[1] = *(const u_int8_t *)w;
+ sum += s_util.s;
+ w = (const u_int16_t *)(void *)((const u_int8_t *)w + 1);
+ mlen = vec->len - 1;
+ } else
+ mlen = vec->len;
+ /*
+ * Force to even boundary.
+ */
+ if ((1 & (unsigned long) w) && (mlen > 0)) {
+ REDUCE;
+ sum <<= 8;
+ s_util.c[0] = *(const u_int8_t *)w;
+ w = (const u_int16_t *)(void *)((const u_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] = *(const u_int8_t *)w;
+ sum += s_util.s;
+ mlen = 0;
+ } else
+ mlen = -1;
+ } else if (mlen == -1)
+ s_util.c[0] = *(const u_int8_t *)w;
+ }
+ 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);
+}
+
+/*
+ * Given the host-byte-order value of the checksum field in a packet
+ * header, and the network-byte-order computed checksum of the data
+ * that the checksum covers (including the checksum itself), compute
+ * what the checksum field *should* have been.
+ */
+u_int16_t
+in_cksum_shouldbe(u_int16_t sum, u_int16_t computed_sum)
+{
+ u_int32_t shouldbe;
+
+ /*
+ * The value that should have gone into the checksum field
+ * is the negative of the value gotten by summing up everything
+ * *but* the checksum field.
+ *
+ * We can compute that by subtracting the value of the checksum
+ * field from the sum of all the data in the packet, and then
+ * computing the negative of that value.
+ *
+ * "sum" is the value of the checksum field, and "computed_sum"
+ * is the negative of the sum of all the data in the packets,
+ * so that's -(-computed_sum - sum), or (sum + computed_sum).
+ *
+ * All the arithmetic in question is one's complement, so the
+ * addition must include an end-around carry; we do this by
+ * doing the arithmetic in 32 bits (with no sign-extension),
+ * and then adding the upper 16 bits of the sum, which contain
+ * the carry, to the lower 16 bits of the sum, and then do it
+ * again in case *that* sum produced a carry.
+ *
+ * As RFC 1071 notes, the checksum can be computed without
+ * byte-swapping the 16-bit words; summing 16-bit words
+ * on a big-endian machine gives a big-endian checksum, which
+ * can be directly stuffed into the big-endian checksum fields
+ * in protocol headers, and summing words on a little-endian
+ * machine gives a little-endian checksum, which must be
+ * byte-swapped before being stuffed into a big-endian checksum
+ * field.
+ *
+ * "computed_sum" is a network-byte-order value, so we must put
+ * it in host byte order before subtracting it from the
+ * host-byte-order value from the header; the adjusted checksum
+ * will be in host byte order, which is what we'll return.
+ */
+ shouldbe = sum;
+ shouldbe += ntohs(computed_sum);
+ shouldbe = (shouldbe & 0xFFFF) + (shouldbe >> 16);
+ shouldbe = (shouldbe & 0xFFFF) + (shouldbe >> 16);
+ return shouldbe;
+}