Fix and add a workaround on an issue of EtherIP packet with reversed

version field sent via gif(4)+if_bridge(4).  The EtherIP
implementation found on FreeBSD 6.1, 6.2, 6.3, 7.0, 7.1, and 7.2 had
an interoperability issue because it sent the incorrect EtherIP
packets and discarded the correct ones.

This change introduces the following two flags to gif(4):

 accept_rev_ethip_ver: accepts both correct EtherIP packets and ones
    with reversed version field, if enabled.  If disabled, the gif
    accepts the correct packets only.  This flag is enabled by
    default.

 send_rev_ethip_ver: sends EtherIP packets with reversed version field
    intentionally, if enabled.  If disabled, the gif sends the correct
    packets only.  This flag is disabled by default.

These flags are stored in struct gif_softc and can be set by
ifconfig(8) on per-interface basis.

Note that this is an incompatible change of EtherIP with the older
FreeBSD releases.  If you need to interoperate older FreeBSD boxes and
new versions after this commit, setting "send_rev_ethip_ver" is
needed.

Reviewed by:	thompsa and rwatson
Spotted by:	Shunsuke SHINOMIYA
PR:		kern/125003
MFC after:	2 weeks

2 files changed, 133 insertions, 0 deletions

diff --git a/sbin/ifconfig/Makefile b/sbin/ifconfig/Makefile
index 087b3a0..c97f14d 100644
--- a/sbin/ifconfig/Makefile
+++ b/sbin/ifconfig/Makefile
@@ -24,6 +24,7 @@ SRCS+=	ifmac.c			# MAC support
 SRCS+=	ifmedia.c		# SIOC[GS]IFMEDIA support
 SRCS+=	ifvlan.c		# SIOC[GS]ETVLAN support
 SRCS+=	ifgre.c			# GRE keys etc
+SRCS+=	ifgif.c			# GIF reversed header workaround
 
 SRCS+=	ifieee80211.c regdomain.c # SIOC[GS]IEEE80211 support
 DPADD+=	${LIBBSDXML} ${LIBSBUF}
diff --git a/sbin/ifconfig/ifgif.c b/sbin/ifconfig/ifgif.c
new file mode 100644
index 0000000..92ee4c8
--- /dev/null
+++ b/sbin/ifconfig/ifgif.c
@@ -0,0 +1,132 @@
+/*-
+ * Copyright (c) 2009 Hiroki Sato.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR OR HIS RELATIVES BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF MIND, USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef lint
+static const char rcsid[] =
+  "$FreeBSD$";
+#endif
+
+#include <sys/param.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <sys/sockio.h>
+
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <net/ethernet.h>
+#include <net/if.h>
+#include <net/if_gif.h>
+#include <net/route.h>
+
+#include <ctype.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <err.h>
+#include <errno.h>
+
+#include "ifconfig.h"
+
+static void	gif_status(int);
+
+static struct {
+	const char	*label;
+	u_int		mask;
+} gif_opts[] = {
+	{ "ACCEPT_REV_ETHIP_VER",	GIF_ACCEPT_REVETHIP	},
+	{ "SEND_REV_ETHIP_VER",		GIF_SEND_REVETHIP	},
+};
+
+static void
+gif_status(int s)
+{
+	int opts;
+	int nopts = 0;
+	int i;
+
+	ifr.ifr_data = (caddr_t)&opts;
+	if (ioctl(s, GIFGOPTS, &ifr) == -1)
+		return;
+
+	printf("\toptions=%d<", opts);
+	for (i=0; i < sizeof(gif_opts)/sizeof(gif_opts[0]); i++) {
+		if (opts & gif_opts[i].mask) {
+			if (nopts++)
+				printf(",");
+			printf("%s", gif_opts[i].label);
+		}
+	}
+	printf(">\n");
+}
+
+static void
+setgifopts(const char *val,
+	int d, int s, const struct afswtch *afp)
+{
+	int opts;
+
+	ifr.ifr_data = (caddr_t)&opts;
+	if (ioctl(s, GIFGOPTS, &ifr) == -1) {
+		warn("ioctl(GIFGOPTS)");
+		return;
+	}
+
+	if (d < 0)
+		opts &= ~(-d);
+	else
+		opts |= d;
+
+	if (ioctl(s, GIFSOPTS, &ifr) == -1) {
+		warn("ioctl(GIFSOPTS)");
+		return;
+	}
+}
+
+static struct cmd gif_cmds[] = {
+	DEF_CMD("accept_rev_ethip_ver",	GIF_ACCEPT_REVETHIP,	setgifopts),
+	DEF_CMD("-accept_rev_ethip_ver",-GIF_ACCEPT_REVETHIP,	setgifopts),
+	DEF_CMD("send_rev_ethip_ver",	GIF_SEND_REVETHIP,	setgifopts),
+	DEF_CMD("-send_rev_ethip_ver",	-GIF_SEND_REVETHIP,	setgifopts),
+};
+
+static struct afswtch af_gif = {
+	.af_name	= "af_gif",
+	.af_af		= AF_UNSPEC,
+	.af_other_status = gif_status,
+};
+
+static __constructor void
+gif_ctor(void)
+{
+#define	N(a)	(sizeof(a) / sizeof(a[0]))
+	int i;
+
+	for (i = 0; i < N(gif_cmds); i++)
+		cmd_register(&gif_cmds[i]);
+	af_register(&af_gif);
+#undef N
+}