ping: Move in_cksum() to a separate source file

This is a preparation step for adding ATF tests of in_cksum(), which has been
modified to operate on unaligned data. ping.o cannot be linked to the test
executable because both of them contain 'main' symbol.

Submitted by:	Ján Sučan <sucanjan@gmail.com>
MFC after:	2 weeks
Sponsored by:	Google, inc. (Google Summer of Code 2019)
Differential Revision:	https://reviews.freebsd.org/D21288

4 files changed, 139 insertions, 48 deletions

diff --git a/sbin/ping/Makefile b/sbin/ping/Makefile
index 3147376b80ff..5113ebdbe2d4 100644
--- a/sbin/ping/Makefile
+++ b/sbin/ping/Makefile
@@ -5,6 +5,7 @@
 
 PACKAGE=runtime
 PROG=	ping
+SRCS=	ping.c utils.c
 MAN=	ping.8
 BINOWN=	root
 BINMODE=4555
diff --git a/sbin/ping/ping.c b/sbin/ping/ping.c
index 18a5010644dd..810150a7d30a 100644
--- a/sbin/ping/ping.c
+++ b/sbin/ping/ping.c
@@ -99,6 +99,8 @@ __FBSDID("$FreeBSD$");
 #include <time.h>
 #include <unistd.h>
 
+#include "utils.h"
+
 #define	INADDR_LEN	((int)sizeof(in_addr_t))
 #define	TIMEVAL_LEN	((int)sizeof(struct tv32))
 #define	MASK_LEN	(ICMP_MASKLEN - ICMP_MINLEN)
@@ -209,7 +211,6 @@ static volatile sig_atomic_t siginfo_p;
 static cap_channel_t *capdns;
 
 static void fill(char *, char *);
-static u_short in_cksum(u_char *, int);
 static cap_channel_t *capdns_setup(void);
 static void check_status(void);
 static void finish(void) __dead2;
@@ -1344,53 +1345,6 @@ pr_pack(char *buf, int cc, struct sockaddr_in *from, struct timespec *tv)
 }
 
 /*
- * in_cksum --
- *	Checksum routine for Internet Protocol family headers (C Version)
- */
-u_short
-in_cksum(u_char *addr, int len)
-{
-	int nleft, sum;
-	u_char *w;
-	union {
-		u_short	us;
-		u_char	uc[2];
-	} last;
-	u_short answer;
-
-	nleft = len;
-	sum = 0;
-	w = addr;
-
-	/*
-	 * Our algorithm is simple, using a 32 bit accumulator (sum), we add
-	 * sequential 16 bit words to it, and at the end, fold back all the
-	 * carry bits from the top 16 bits into the lower 16 bits.
-	 */
-	while (nleft > 1)  {
-		u_short data;
-
-		memcpy(&data, w, sizeof(data));
-		sum += data;
-		w += sizeof(data);
-		nleft -= sizeof(data);
-	}
-
-	/* mop up an odd byte, if necessary */
-	if (nleft == 1) {
-		last.uc[0] = *w;
-		last.uc[1] = 0;
-		sum += last.us;
-	}
-
-	/* add back carry outs from top 16 bits to low 16 bits */
-	sum = (sum >> 16) + (sum & 0xffff);	/* add hi 16 to low 16 */
-	sum += (sum >> 16);			/* add carry */
-	answer = ~sum;				/* truncate to 16 bits */
-	return(answer);
-}
-
-/*
  * status --
  *	Print out statistics when SIGINFO is received.
  */
diff --git a/sbin/ping/utils.c b/sbin/ping/utils.c
new file mode 100644
index 000000000000..1df233995bf0
--- /dev/null
+++ b/sbin/ping/utils.c
@@ -0,0 +1,98 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1989, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Mike Muuss.
+ *
+ * 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.
+ */
+
+#if 0
+#ifndef lint
+static const char copyright[] =
+"@(#) Copyright (c) 1989, 1993\n\
+	The Regents of the University of California.  All rights reserved.\n";
+#endif /* not lint */
+
+#ifndef lint
+static char sccsid[] = "@(#)ping.c	8.1 (Berkeley) 6/5/93";
+#endif /* not lint */
+#endif
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <string.h>
+
+#include "utils.h"
+
+/*
+ * in_cksum --
+ *	Checksum routine for Internet Protocol family headers (C Version)
+ */
+u_short
+in_cksum(u_char *addr, int len)
+{
+	int nleft, sum;
+	u_char *w;
+	union {
+		u_short	us;
+		u_char	uc[2];
+	} last;
+	u_short answer;
+
+	nleft = len;
+	sum = 0;
+	w = addr;
+
+	/*
+	 * Our algorithm is simple, using a 32 bit accumulator (sum), we add
+	 * sequential 16 bit words to it, and at the end, fold back all the
+	 * carry bits from the top 16 bits into the lower 16 bits.
+	 */
+	while (nleft > 1)  {
+		u_short data;
+
+		memcpy(&data, w, sizeof(data));
+		sum += data;
+		w += sizeof(data);
+		nleft -= sizeof(data);
+	}
+
+	/* mop up an odd byte, if necessary */
+	if (nleft == 1) {
+		last.uc[0] = *w;
+		last.uc[1] = 0;
+		sum += last.us;
+	}
+
+	/* add back carry outs from top 16 bits to low 16 bits */
+	sum = (sum >> 16) + (sum & 0xffff);	/* add hi 16 to low 16 */
+	sum += (sum >> 16);			/* add carry */
+	answer = ~sum;				/* truncate to 16 bits */
+	return(answer);
+}
diff --git a/sbin/ping/utils.h b/sbin/ping/utils.h
new file mode 100644
index 000000000000..3c2bfaebd334
--- /dev/null
+++ b/sbin/ping/utils.h
@@ -0,0 +1,38 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright (C) 2019 Jan Sucan <jansucan@FreeBSD.org>
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef PING_H
+#define PING_H 1
+
+#include <sys/types.h>
+
+u_short in_cksum(u_char *, int);
+
+#endif