ila: Add generic ILA translation facility

This patch implements an ILA tanslation table. This table can be
configured with identifier to locator mappings, and can be be queried
to resolve a mapping. Queries can be parameterized based on interface,
direction (incoming or outoing), and matching locator.  The table is
implemented using rhashtable and is configured via netlink (through
"ip ila .." in iproute).

The table may be used as alternative means to do do ILA tanslations
other than the lw tunnels
Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ila.h

+/*
+ * ILA kernel interface
+ *
+ * Copyright (c) 2015 Tom Herbert <tom@herbertland.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ */
+
+#ifndef _NET_ILA_H
+#define _NET_ILA_H
+
+int ila_xlat_outgoing(struct sk_buff *skb);
+int ila_xlat_incoming(struct sk_buff *skb);
+
+#endif /* _NET_ILA_H */

include/uapi/linux/ila.h

@@ -3,13 +3,35 @@
 #ifndef _UAPI_LINUX_ILA_H
 #define _UAPI_LINUX_ILA_H
 
+/* NETLINK_GENERIC related info */
+#define ILA_GENL_NAME		"ila"
+#define ILA_GENL_VERSION	0x1
+
 enum {
 	ILA_ATTR_UNSPEC,
 	ILA_ATTR_LOCATOR,			/* u64 */
+	ILA_ATTR_IDENTIFIER,			/* u64 */
+	ILA_ATTR_LOCATOR_MATCH,			/* u64 */
+	ILA_ATTR_IFINDEX,			/* s32 */
+	ILA_ATTR_DIR,				/* u32 */
 
 	__ILA_ATTR_MAX,
 };
 
 #define ILA_ATTR_MAX		(__ILA_ATTR_MAX - 1)
 
+enum {
+	ILA_CMD_UNSPEC,
+	ILA_CMD_ADD,
+	ILA_CMD_DEL,
+	ILA_CMD_GET,
+
+	__ILA_CMD_MAX,
+};
+
+#define ILA_CMD_MAX	(__ILA_CMD_MAX - 1)
+
+#define ILA_DIR_IN	(1 << 0)
+#define ILA_DIR_OUT	(1 << 1)
+
 #endif /* _UAPI_LINUX_ILA_H */

net/ipv6/ila/Makefile

@@ -4,4 +4,4 @@
 
 obj-$(CONFIG_IPV6_ILA) += ila.o
 
-ila-objs := ila_common.o ila_lwt.o
+ila-objs := ila_common.o ila_lwt.o ila_xlat.o

net/ipv6/ila/ila.h

@@ -42,5 +42,7 @@ void update_ipv6_locator(struct sk_buff *skb, struct ila_params *p);
 
 int ila_lwt_init(void);
 void ila_lwt_fini(void);
+int ila_xlat_init(void);
+void ila_xlat_fini(void);
 
 #endif /* __ILA_H */

net/ipv6/ila/ila_common.c

@@ -80,12 +80,20 @@ static int __init ila_init(void)
 	if (ret)
 		goto fail_lwt;
 
+	ret = ila_xlat_init();
+	if (ret)
+		goto fail_xlat;
+
+	return 0;
+fail_xlat:
+	ila_lwt_fini();
 fail_lwt:
 	return ret;
 }
 
 static void __exit ila_fini(void)
 {
+	ila_xlat_fini();
 	ila_lwt_fini();
 }