linux/net/ipv6/ila/ila_lwt.c
Tom Herbert fddb231ebe ila: Add a hook type for LWT routes
In LWT tunnels both an input and output route method is defined.
If both of these are executed in the same path then double translation
happens and the effect is not correct.

This patch adds a new attribute that indicates the hook type. Two
values are defined for route output and route output. ILA
translation is only done for the one that is set. The default is
to enable ILA on route output.

Signed-off-by: Tom Herbert <tom@quantonium.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-08 11:20:49 +09:00

325 lines
7.6 KiB
C

// SPDX-License-Identifier: GPL-2.0
#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/dst_cache.h>
#include <net/ip.h>
#include <net/ip6_fib.h>
#include <net/ip6_route.h>
#include <net/lwtunnel.h>
#include <net/protocol.h>
#include <uapi/linux/ila.h>
#include "ila.h"
struct ila_lwt {
struct ila_params p;
struct dst_cache dst_cache;
u32 connected : 1;
u32 lwt_output : 1;
};
static inline struct ila_lwt *ila_lwt_lwtunnel(
struct lwtunnel_state *lwt)
{
return (struct ila_lwt *)lwt->data;
}
static inline struct ila_params *ila_params_lwtunnel(
struct lwtunnel_state *lwt)
{
return &ila_lwt_lwtunnel(lwt)->p;
}
static int ila_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
struct dst_entry *orig_dst = skb_dst(skb);
struct rt6_info *rt = (struct rt6_info *)orig_dst;
struct ila_lwt *ilwt = ila_lwt_lwtunnel(orig_dst->lwtstate);
struct dst_entry *dst;
int err = -EINVAL;
if (skb->protocol != htons(ETH_P_IPV6))
goto drop;
if (ilwt->lwt_output)
ila_update_ipv6_locator(skb,
ila_params_lwtunnel(orig_dst->lwtstate),
true);
if (rt->rt6i_flags & (RTF_GATEWAY | RTF_CACHE)) {
/* Already have a next hop address in route, no need for
* dest cache route.
*/
return orig_dst->lwtstate->orig_output(net, sk, skb);
}
dst = dst_cache_get(&ilwt->dst_cache);
if (unlikely(!dst)) {
struct ipv6hdr *ip6h = ipv6_hdr(skb);
struct flowi6 fl6;
/* Lookup a route for the new destination. Take into
* account that the base route may already have a gateway.
*/
memset(&fl6, 0, sizeof(fl6));
fl6.flowi6_oif = orig_dst->dev->ifindex;
fl6.flowi6_iif = LOOPBACK_IFINDEX;
fl6.daddr = *rt6_nexthop((struct rt6_info *)orig_dst,
&ip6h->daddr);
dst = ip6_route_output(net, NULL, &fl6);
if (dst->error) {
err = -EHOSTUNREACH;
dst_release(dst);
goto drop;
}
dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), NULL, 0);
if (IS_ERR(dst)) {
err = PTR_ERR(dst);
goto drop;
}
if (ilwt->connected)
dst_cache_set_ip6(&ilwt->dst_cache, dst, &fl6.saddr);
}
skb_dst_set(skb, dst);
return dst_output(net, sk, skb);
drop:
kfree_skb(skb);
return err;
}
static int ila_input(struct sk_buff *skb)
{
struct dst_entry *dst = skb_dst(skb);
struct ila_lwt *ilwt = ila_lwt_lwtunnel(dst->lwtstate);
if (skb->protocol != htons(ETH_P_IPV6))
goto drop;
if (!ilwt->lwt_output)
ila_update_ipv6_locator(skb,
ila_params_lwtunnel(dst->lwtstate),
false);
return dst->lwtstate->orig_input(skb);
drop:
kfree_skb(skb);
return -EINVAL;
}
static const struct nla_policy ila_nl_policy[ILA_ATTR_MAX + 1] = {
[ILA_ATTR_LOCATOR] = { .type = NLA_U64, },
[ILA_ATTR_CSUM_MODE] = { .type = NLA_U8, },
[ILA_ATTR_IDENT_TYPE] = { .type = NLA_U8, },
[ILA_ATTR_HOOK_TYPE] = { .type = NLA_U8, },
};
static int ila_build_state(struct nlattr *nla,
unsigned int family, const void *cfg,
struct lwtunnel_state **ts,
struct netlink_ext_ack *extack)
{
struct ila_lwt *ilwt;
struct ila_params *p;
struct nlattr *tb[ILA_ATTR_MAX + 1];
struct lwtunnel_state *newts;
const struct fib6_config *cfg6 = cfg;
struct ila_addr *iaddr;
u8 ident_type = ILA_ATYPE_USE_FORMAT;
u8 hook_type = ILA_HOOK_ROUTE_OUTPUT;
u8 csum_mode = ILA_CSUM_NO_ACTION;
bool lwt_output = true;
u8 eff_ident_type;
int ret;
if (family != AF_INET6)
return -EINVAL;
ret = nla_parse_nested(tb, ILA_ATTR_MAX, nla, ila_nl_policy, extack);
if (ret < 0)
return ret;
if (!tb[ILA_ATTR_LOCATOR])
return -EINVAL;
iaddr = (struct ila_addr *)&cfg6->fc_dst;
if (tb[ILA_ATTR_IDENT_TYPE])
ident_type = nla_get_u8(tb[ILA_ATTR_IDENT_TYPE]);
if (ident_type == ILA_ATYPE_USE_FORMAT) {
/* Infer identifier type from type field in formatted
* identifier.
*/
if (cfg6->fc_dst_len < 8 * sizeof(struct ila_locator) + 3) {
/* Need to have full locator and at least type field
* included in destination
*/
return -EINVAL;
}
eff_ident_type = iaddr->ident.type;
} else {
eff_ident_type = ident_type;
}
switch (eff_ident_type) {
case ILA_ATYPE_IID:
/* Don't allow ILA for IID type */
return -EINVAL;
case ILA_ATYPE_LUID:
break;
case ILA_ATYPE_VIRT_V4:
case ILA_ATYPE_VIRT_UNI_V6:
case ILA_ATYPE_VIRT_MULTI_V6:
case ILA_ATYPE_NONLOCAL_ADDR:
/* These ILA formats are not supported yet. */
default:
return -EINVAL;
}
if (tb[ILA_ATTR_HOOK_TYPE])
hook_type = nla_get_u8(tb[ILA_ATTR_HOOK_TYPE]);
switch (hook_type) {
case ILA_HOOK_ROUTE_OUTPUT:
lwt_output = true;
break;
case ILA_HOOK_ROUTE_INPUT:
lwt_output = false;
break;
default:
return -EINVAL;
}
if (tb[ILA_ATTR_CSUM_MODE])
csum_mode = nla_get_u8(tb[ILA_ATTR_CSUM_MODE]);
if (csum_mode == ILA_CSUM_NEUTRAL_MAP &&
ila_csum_neutral_set(iaddr->ident)) {
/* Don't allow translation if checksum neutral bit is
* configured and it's set in the SIR address.
*/
return -EINVAL;
}
newts = lwtunnel_state_alloc(sizeof(*ilwt));
if (!newts)
return -ENOMEM;
ilwt = ila_lwt_lwtunnel(newts);
ret = dst_cache_init(&ilwt->dst_cache, GFP_ATOMIC);
if (ret) {
kfree(newts);
return ret;
}
ilwt->lwt_output = !!lwt_output;
p = ila_params_lwtunnel(newts);
p->csum_mode = csum_mode;
p->ident_type = ident_type;
p->locator.v64 = (__force __be64)nla_get_u64(tb[ILA_ATTR_LOCATOR]);
/* Precompute checksum difference for translation since we
* know both the old locator and the new one.
*/
p->locator_match = iaddr->loc;
ila_init_saved_csum(p);
newts->type = LWTUNNEL_ENCAP_ILA;
newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT |
LWTUNNEL_STATE_INPUT_REDIRECT;
if (cfg6->fc_dst_len == 8 * sizeof(struct in6_addr))
ilwt->connected = 1;
*ts = newts;
return 0;
}
static void ila_destroy_state(struct lwtunnel_state *lwt)
{
dst_cache_destroy(&ila_lwt_lwtunnel(lwt)->dst_cache);
}
static int ila_fill_encap_info(struct sk_buff *skb,
struct lwtunnel_state *lwtstate)
{
struct ila_params *p = ila_params_lwtunnel(lwtstate);
struct ila_lwt *ilwt = ila_lwt_lwtunnel(lwtstate);
if (nla_put_u64_64bit(skb, ILA_ATTR_LOCATOR, (__force u64)p->locator.v64,
ILA_ATTR_PAD))
goto nla_put_failure;
if (nla_put_u8(skb, ILA_ATTR_CSUM_MODE, (__force u8)p->csum_mode))
goto nla_put_failure;
if (nla_put_u8(skb, ILA_ATTR_IDENT_TYPE, (__force u8)p->ident_type))
goto nla_put_failure;
if (nla_put_u8(skb, ILA_ATTR_HOOK_TYPE,
ilwt->lwt_output ? ILA_HOOK_ROUTE_OUTPUT :
ILA_HOOK_ROUTE_INPUT))
goto nla_put_failure;
return 0;
nla_put_failure:
return -EMSGSIZE;
}
static int ila_encap_nlsize(struct lwtunnel_state *lwtstate)
{
return nla_total_size_64bit(sizeof(u64)) + /* ILA_ATTR_LOCATOR */
nla_total_size(sizeof(u8)) + /* ILA_ATTR_CSUM_MODE */
nla_total_size(sizeof(u8)) + /* ILA_ATTR_IDENT_TYPE */
nla_total_size(sizeof(u8)) + /* ILA_ATTR_HOOK_TYPE */
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.v64 != b_p->locator.v64);
}
static const struct lwtunnel_encap_ops ila_encap_ops = {
.build_state = ila_build_state,
.destroy_state = ila_destroy_state,
.output = ila_output,
.input = ila_input,
.fill_encap = ila_fill_encap_info,
.get_encap_size = ila_encap_nlsize,
.cmp_encap = ila_encap_cmp,
.owner = THIS_MODULE,
};
int ila_lwt_init(void)
{
return lwtunnel_encap_add_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
}
void ila_lwt_fini(void)
{
lwtunnel_encap_del_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
}