net: Identifier Locator Addressing module
authorTom Herbert <tom@herbertland.com>
Mon, 17 Aug 2015 20:42:27 +0000 (13:42 -0700)
committerDavid S. Miller <davem@davemloft.net>
Tue, 18 Aug 2015 04:33:06 +0000 (21:33 -0700)
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: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
include/uapi/linux/ila.h [new file with mode: 0644]
include/uapi/linux/lwtunnel.h
net/ipv6/Kconfig
net/ipv6/Makefile
net/ipv6/ila.c [new file with mode: 0644]

diff --git a/include/uapi/linux/ila.h b/include/uapi/linux/ila.h
new file mode 100644 (file)
index 0000000..7ed9e67
--- /dev/null
@@ -0,0 +1,15 @@
+/* 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 */
index 3bf223bc2367a903e064d1dc8af60671472e8f12..aa84ca396bcbcc119c3ed4016b06870901dc1d51 100644 (file)
@@ -7,6 +7,7 @@ enum lwtunnel_encap_types {
        LWTUNNEL_ENCAP_NONE,
        LWTUNNEL_ENCAP_MPLS,
        LWTUNNEL_ENCAP_IP,
+       LWTUNNEL_ENCAP_ILA,
        __LWTUNNEL_ENCAP_MAX,
 };
 
index 643f61339e7b4fc9d4dcba75c4bb772c99d39292..983bb999738c4dbe1c6b084f5cc75da7d14b1543 100644 (file)
@@ -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
index 0f3f1999719ac72617b14e68c13f2662f66054a7..2c900c7b7eb1c45b1619a42275552861bdfcda44 100644 (file)
@@ -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
diff --git a/net/ipv6/ila.c b/net/ipv6/ila.c
new file mode 100644 (file)
index 0000000..2540ab4
--- /dev/null
@@ -0,0 +1,216 @@
+#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");