Commit 65d7ab8d authored by Tom Herbert's avatar Tom Herbert Committed by David S. Miller
Browse files

net: Identifier Locator Addressing module 



Adding new module name ila. This implements ILA translation. Light
weight tunnel redirection is used to perform the translation in
the data path. This is configured by the "ip -6 route" command
using the "encap ila <locator>" option, where <locator> is the
value to set in destination locator of the packet. e.g.

ip -6 route add 3333:0:0:1:5555:0:1:0/128 \
      encap ila 2001:0:0:1 via 2401:db00:20:911a:face:0:25:0

Sets a route where 3333:0:0:1 will be overwritten by
2001:0:0:1 on output.

Signed-off-by: default avatarTom Herbert <tom@herbertland.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent abc5d1ff

include/uapi/linux/ila.h

0 → 100644
+15 −0
Original line number Diff line number Diff line 
/* ila.h - ILA Interface */



#ifndef _UAPI_LINUX_ILA_H

#define _UAPI_LINUX_ILA_H



enum {

	ILA_ATTR_UNSPEC,

	ILA_ATTR_LOCATOR,			/* u64 */



	__ILA_ATTR_MAX,

};



#define ILA_ATTR_MAX		(__ILA_ATTR_MAX - 1)



#endif /* _UAPI_LINUX_ILA_H */

include/uapi/linux/lwtunnel.h

+1 −0
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ enum lwtunnel_encap_types { 
	LWTUNNEL_ENCAP_NONE,

	LWTUNNEL_ENCAP_MPLS,

	LWTUNNEL_ENCAP_IP,

	LWTUNNEL_ENCAP_ILA,

	__LWTUNNEL_ENCAP_MAX,

};

net/ipv6/Kconfig

+19 −0
Original line number Diff line number Diff line
@@ -92,6 +92,25 @@ config IPV6_MIP6 


	  If unsure, say N.



config IPV6_ILA

	tristate "IPv6: Identifier Locator Addressing (ILA)"

	select LWTUNNEL

	---help---

	  Support for IPv6 Identifier Locator Addressing (ILA).



	  ILA is a mechanism to do network virtualization without

	  encapsulation. The basic concept of ILA is that we split an

	  IPv6 address into a 64 bit locator and 64 bit identifier. The

	  identifier is the identity of an entity in communication

	  ("who") and the locator expresses the location of the

	  entity ("where").



	  ILA can be configured using the "encap ila" option with

	  "ip -6 route" command. ILA is described in

	  https://tools.ietf.org/html/draft-herbert-nvo3-ila-00.



	  If unsure, say N.



config INET6_XFRM_TUNNEL

	tristate

	select INET6_TUNNEL

net/ipv6/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ obj-$(CONFIG_INET6_XFRM_MODE_TUNNEL) += xfrm6_mode_tunnel.o 
obj-$(CONFIG_INET6_XFRM_MODE_ROUTEOPTIMIZATION) += xfrm6_mode_ro.o

obj-$(CONFIG_INET6_XFRM_MODE_BEET) += xfrm6_mode_beet.o

obj-$(CONFIG_IPV6_MIP6) += mip6.o

obj-$(CONFIG_IPV6_ILA) += ila.o

obj-$(CONFIG_NETFILTER)	+= netfilter/



obj-$(CONFIG_IPV6_VTI) += ip6_vti.o

net/ipv6/ila.c

0 → 100644
+216 −0
Original line number Diff line number Diff line 
#include <linux/errno.h>

#include <linux/ip.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/skbuff.h>

#include <linux/socket.h>

#include <linux/types.h>

#include <net/checksum.h>

#include <net/ip.h>

#include <net/ip6_fib.h>

#include <net/lwtunnel.h>

#include <net/protocol.h>

#include <uapi/linux/ila.h>



struct ila_params {

	__be64 locator;

};



static inline struct ila_params *ila_params_lwtunnel(

	struct lwtunnel_state *lwstate)

{

	return (struct ila_params *)lwstate->data;

}



static inline __wsum compute_csum_diff8(const __be32 *from, const __be32 *to)

{

	__be32 diff[] = {

		~from[0], ~from[1], to[0], to[1],

	};



	return csum_partial(diff, sizeof(diff), 0);

}



static inline __wsum get_csum_diff(struct ipv6hdr *ip6h, struct ila_params *p)

{

		return compute_csum_diff8((__be32 *)&ip6h->daddr,

					  (__be32 *)&p->locator);

}



static void update_ipv6_locator(struct sk_buff *skb, struct ila_params *p)

{

	__wsum diff;

	struct ipv6hdr *ip6h = ipv6_hdr(skb);

	size_t nhoff = sizeof(struct ipv6hdr);



	/* First update checksum */

	switch (ip6h->nexthdr) {

	case NEXTHDR_TCP:

		if (likely(pskb_may_pull(skb, nhoff + sizeof(struct tcphdr)))) {

			struct tcphdr *th = (struct tcphdr *)

					(skb_network_header(skb) + nhoff);



			diff = get_csum_diff(ip6h, p);

			inet_proto_csum_replace_by_diff(&th->check, skb,

							diff, true);

		}

		break;

	case NEXTHDR_UDP:

		if (likely(pskb_may_pull(skb, nhoff + sizeof(struct udphdr)))) {

			struct udphdr *uh = (struct udphdr *)

					(skb_network_header(skb) + nhoff);



			if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {

				diff = get_csum_diff(ip6h, p);

				inet_proto_csum_replace_by_diff(&uh->check, skb,

								diff, true);

				if (!uh->check)

					uh->check = CSUM_MANGLED_0;

			}

		}

		break;

	case NEXTHDR_ICMP:

		if (likely(pskb_may_pull(skb,

					 nhoff + sizeof(struct icmp6hdr)))) {

			struct icmp6hdr *ih = (struct icmp6hdr *)

					(skb_network_header(skb) + nhoff);



			diff = get_csum_diff(ip6h, p);

			inet_proto_csum_replace_by_diff(&ih->icmp6_cksum, skb,

							diff, true);

		}

		break;

	}



	/* Now change destination address */

	*(__be64 *)&ip6h->daddr = p->locator;

}



static int ila_output(struct sock *sk, struct sk_buff *skb)

{

	struct dst_entry *dst = skb_dst(skb);

	struct rt6_info *rt6 = NULL;



	if (skb->protocol != htons(ETH_P_IPV6))

		goto drop;



	rt6 = (struct rt6_info *)dst;



	update_ipv6_locator(skb, ila_params_lwtunnel(rt6->rt6i_lwtstate));



	return rt6->rt6i_lwtstate->orig_output(sk, skb);



drop:

	kfree_skb(skb);

	return -EINVAL;

}



static int ila_input(struct sk_buff *skb)

{

	struct dst_entry *dst = skb_dst(skb);

	struct rt6_info *rt6 = NULL;



	if (skb->protocol != htons(ETH_P_IPV6))

		goto drop;



	rt6 = (struct rt6_info *)dst;



	update_ipv6_locator(skb, ila_params_lwtunnel(rt6->rt6i_lwtstate));



	return rt6->rt6i_lwtstate->orig_input(skb);



drop:

	kfree_skb(skb);

	return -EINVAL;

}



static struct nla_policy ila_nl_policy[ILA_ATTR_MAX + 1] = {

	[ILA_ATTR_LOCATOR] = { .type = NLA_U64, },

};



static int ila_build_state(struct net_device *dev, struct nlattr *nla,

			   struct lwtunnel_state **ts)

{

	struct ila_params *p;

	struct nlattr *tb[ILA_ATTR_MAX + 1];

	size_t encap_len = sizeof(*p);

	struct lwtunnel_state *newts;

	int ret;



	ret = nla_parse_nested(tb, ILA_ATTR_MAX, nla,

			       ila_nl_policy);

	if (ret < 0)

		return ret;



	if (!tb[ILA_ATTR_LOCATOR])

		return -EINVAL;



	newts = lwtunnel_state_alloc(encap_len);

	if (!newts)

		return -ENOMEM;



	newts->len = encap_len;

	p = ila_params_lwtunnel(newts);



	p->locator = (__force __be64)nla_get_u64(tb[ILA_ATTR_LOCATOR]);



	newts->type = LWTUNNEL_ENCAP_ILA;

	newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT |

			LWTUNNEL_STATE_INPUT_REDIRECT;



	*ts = newts;



	return 0;

}



static int ila_fill_encap_info(struct sk_buff *skb,

			       struct lwtunnel_state *lwtstate)

{

	struct ila_params *p = ila_params_lwtunnel(lwtstate);



	if (nla_put_u64(skb, ILA_ATTR_LOCATOR, (__force u64)p->locator))

		goto nla_put_failure;



	return 0;



nla_put_failure:

	return -EMSGSIZE;

}



static int ila_encap_nlsize(struct lwtunnel_state *lwtstate)

{

	/* No encapsulation overhead */

	return 0;

}



static int ila_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)

{

	struct ila_params *a_p = ila_params_lwtunnel(a);

	struct ila_params *b_p = ila_params_lwtunnel(b);



	return (a_p->locator != b_p->locator);

}



static const struct lwtunnel_encap_ops ila_encap_ops = {

	.build_state = ila_build_state,

	.output = ila_output,

	.input = ila_input,

	.fill_encap = ila_fill_encap_info,

	.get_encap_size = ila_encap_nlsize,

	.cmp_encap = ila_encap_cmp,

};



static int __init ila_init(void)

{

	return lwtunnel_encap_add_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);

}



static void __exit ila_fini(void)

{

	lwtunnel_encap_del_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);

}



module_init(ila_init);

module_exit(ila_fini);

MODULE_AUTHOR("Tom Herbert <tom@herbertland.com>");

MODULE_LICENSE("GPL");