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xfrm: Move child route linkage into xfrm_dst.

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XFRM bundle child chains look like this:

	xdst1 --> xdst2 --> xdst3 --> path_dst

All of xdstN are xfrm_dst objects and xdst->u.dst.xfrm is non-NULL.
The final child pointer in the chain, here called 'path_dst', is some
other kind of route such as an ipv4 or ipv6 one.

The xfrm output path pops routes, one at a time, via the child
pointer, until we hit one which has a dst->xfrm pointer which
is NULL.

We can easily preserve the above mechanisms with child sitting
only in the xfrm_dst structure.  All children in the chain
before we break out of the xfrm_output() loop have dst->xfrm
non-NULL and are therefore xfrm_dst objects.

Since we break out of the loop when we find dst->xfrm NULL, we
will not try to dereference 'dst' as if it were an xfrm_dst.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Miller
2017-11-28 15:45:44 -05:00
committed by David S. Miller
parent 45b018bedd
commit b6ca8bd5a9
6 changed files with 26 additions and 18 deletions
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15
include/net/xfrm.h
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@@ -968,7 +968,7 @@ static inline bool xfrm_sec_ctx_match(struct xfrm_sec_ctx *s1, struct xfrm_sec_c
/* A struct encoding bundle of transformations to apply to some set of flow.
*
* dst->child points to the next element of bundle.
* xdst->child points to the next element of bundle.
* dst->xfrm points to an instanse of transformer.
*
* Due to unfortunate limitations of current routing cache, which we
@@ -984,6 +984,7 @@ struct xfrm_dst {
struct rt6_info rt6;
} u;
struct dst_entry *route;
struct dst_entry *child;
struct xfrm_policy *pols[XFRM_POLICY_TYPE_MAX];
int num_pols, num_xfrms;
u32 xfrm_genid;
@@ -997,8 +998,10 @@ struct xfrm_dst {
static inline struct dst_entry *xfrm_dst_child(const struct dst_entry *dst)
{
#ifdef CONFIG_XFRM
if (dst->xfrm)
return dst->child;
if (dst->xfrm) {
struct xfrm_dst *xdst = (struct xfrm_dst *) dst;
return xdst->child;
}
#endif
return NULL;
}
@@ -1006,7 +1009,7 @@ static inline struct dst_entry *xfrm_dst_child(const struct dst_entry *dst)
#ifdef CONFIG_XFRM
static inline void xfrm_dst_set_child(struct xfrm_dst *xdst, struct dst_entry *child)
{
xdst->u.dst.child = child;
xdst->child = child;
}
static inline void xfrm_dst_destroy(struct xfrm_dst *xdst)
@@ -1880,12 +1883,14 @@ bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x);
static inline bool xfrm_dst_offload_ok(struct dst_entry *dst)
{
struct xfrm_state *x = dst->xfrm;
struct xfrm_dst *xdst;
if (!x || !x->type_offload)
return false;
xdst = (struct xfrm_dst *) dst;
if (x->xso.offload_handle && (x->xso.dev == dst->path->dev) &&
!dst->child->xfrm)
!xdst->child->xfrm)
return true;
return false;