Add CARP (Common Address Redundancy Protocol), which allows multiple

hosts to share an IP address, providing high availability and load
balancing.

Original work on CARP done by Michael Shalayeff, with many
additions by Marco Pfatschbacher and Ryan McBride.

FreeBSD port done solely by Max Laier.

Patch by:	mlaier
Obtained from:	OpenBSD (mickey, mcbride)

1 files changed, 163 insertions, 0 deletions

diff --git a/sys/netinet/ip_carp.h b/sys/netinet/ip_carp.h
new file mode 100644
index 0000000..a050a88
--- /dev/null
+++ b/sys/netinet/ip_carp.h
@@ -0,0 +1,163 @@
+/*	$FreeBSD$	*/
+/*	$OpenBSD: ip_carp.h,v 1.8 2004/07/29 22:12:15 mcbride Exp $	*/
+
+/*
+ * Copyright (c) 2002 Michael Shalayeff. All rights reserved.
+ * Copyright (c) 2003 Ryan McBride. 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 _IP_CARP_H
+#define	_IP_CARP_H
+
+/*
+ * The CARP header layout is as follows:
+ *
+ *     0                   1                   2                   3
+ *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *    |Version| Type  | VirtualHostID |    AdvSkew    |    Auth Len   |
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *    |   Reserved    |     AdvBase   |          Checksum             |
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *    |                         Counter (1)                           |
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *    |                         Counter (2)                           |
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *    |                        SHA-1 HMAC (1)                         |
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *    |                        SHA-1 HMAC (2)                         |
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *    |                        SHA-1 HMAC (3)                         |
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *    |                        SHA-1 HMAC (4)                         |
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *    |                        SHA-1 HMAC (5)                         |
+ *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ */
+
+struct carp_header {
+#if BYTE_ORDER == LITTLE_ENDIAN
+	u_int8_t	carp_type:4,
+			carp_version:4;
+#endif
+#if BYTE_ORDER == BIG_ENDIAN
+	u_int8_t	carp_version:4,
+			carp_type:4;
+#endif
+	u_int8_t	carp_vhid;	/* virtual host id */
+	u_int8_t	carp_advskew;	/* advertisement skew */
+	u_int8_t	carp_authlen;   /* size of counter+md, 32bit chunks */
+	u_int8_t	carp_pad1;	/* reserved */
+	u_int8_t	carp_advbase;	/* advertisement interval */
+	u_int16_t	carp_cksum;
+	u_int32_t	carp_counter[2];
+	unsigned char	carp_md[20];	/* SHA1 HMAC */
+} __packed;
+
+#define	CARP_DFLTTL		255
+
+/* carp_version */
+#define	CARP_VERSION		2
+
+/* carp_type */
+#define	CARP_ADVERTISEMENT	0x01
+
+#define	CARP_KEY_LEN		20	/* a sha1 hash of a passphrase */
+
+/* carp_advbase */
+#define	CARP_DFLTINTV		1
+
+/*
+ * Statistics.
+ */
+struct carpstats {
+	uint64_t	carps_ipackets;		/* total input packets, IPv4 */
+	uint64_t	carps_ipackets6;	/* total input packets, IPv6 */
+	uint64_t	carps_badif;		/* wrong interface */
+	uint64_t	carps_badttl;		/* TTL is not CARP_DFLTTL */
+	uint64_t	carps_hdrops;		/* packets shorter than hdr */
+	uint64_t	carps_badsum;		/* bad checksum */
+	uint64_t	carps_badver;		/* bad (incl unsupp) version */
+	uint64_t	carps_badlen;		/* data length does not match */
+	uint64_t	carps_badauth;		/* bad authentication */
+	uint64_t	carps_badvhid;		/* bad VHID */
+	uint64_t	carps_badaddrs;		/* bad address list */
+
+	uint64_t	carps_opackets;		/* total output packets, IPv4 */
+	uint64_t	carps_opackets6;	/* total output packets, IPv6 */
+	uint64_t	carps_onomem;		/* no memory for an mbuf */
+	uint64_t	carps_ostates;		/* total state updates sent */
+
+	uint64_t	carps_preempt;		/* if enabled, preemptions */
+};
+
+/*
+ * Configuration structure for SIOCSVH SIOCGVH
+ */
+struct carpreq {
+	int		carpr_state;
+#define	CARP_STATES	"INIT", "BACKUP", "MASTER"
+#define	CARP_MAXSTATE	2
+	int		carpr_vhid;
+	int		carpr_advskew;
+	int		carpr_advbase;
+	unsigned char	carpr_key[CARP_KEY_LEN];
+};
+#define	SIOCSVH	_IOWR('i', 245, struct ifreq)
+#define	SIOCGVH	_IOWR('i', 246, struct ifreq)
+
+/*
+ * Names for CARP sysctl objects
+ */
+#define	CARPCTL_ALLOW		1	/* accept incoming CARP packets */
+#define	CARPCTL_PREEMPT		2	/* high-pri backup preemption mode */
+#define	CARPCTL_LOG		3	/* log bad packets */
+#define	CARPCTL_STATS		4	/* statistics (read-only) */
+#define	CARPCTL_ARPBALANCE	5	/* balance arp responses */
+#define	CARPCTL_MAXID		6
+
+#define	CARPCTL_NAMES { \
+	{ 0, 0 }, \
+	{ "allow", CTLTYPE_INT }, \
+	{ "preempt", CTLTYPE_INT }, \
+	{ "log", CTLTYPE_INT }, \
+	{ "stats", CTLTYPE_STRUCT }, \
+	{ "arpbalance", CTLTYPE_INT }, \
+}
+
+#ifdef _KERNEL
+void		 carp_ifdetach (struct ifnet *);
+void		 carp_carpdev_state(void *);
+void		 carp_input (struct mbuf *, int);
+int		 carp6_input (struct mbuf **, int *, int);
+int		 carp_output (struct ifnet *, struct mbuf *, struct sockaddr *,
+		     struct rtentry *);
+int		 carp_iamatch (void *, struct in_ifaddr *, struct in_addr *,
+		     u_int8_t **);
+struct ifaddr	*carp_iamatch6(void *, struct in6_addr *);
+void		*carp_macmatch6(void *, struct mbuf *, const struct in6_addr *);
+struct	ifnet	*carp_forus (void *, void *);
+#endif
+#endif /* _IP_CARP_H */