xfrm: Move child route linkage into xfrm_dst.

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>

diff --git a/include/net/dst.h b/include/net/dst.h
index acbb3fb..cef4620 100644 (file)
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -35,7 +35,6 @@ struct sk_buff;
 struct dst_entry {
        struct net_device       *dev;
        struct rcu_head         rcu_head;
-       struct dst_entry        *child;
        struct  dst_ops         *ops;
        unsigned long           _metrics;
        unsigned long           expires;
@@ -89,7 +88,7 @@ struct dst_entry {
         * Align __refcnt to a 64 bytes alignment
         * (L1_CACHE_SIZE would be too much)
         */
-       long                    __pad_to_align_refcnt[2];
+       long                    __pad_to_align_refcnt[3];
 #endif
        /*
         * __refcnt wants to be on a different cache line from

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 4c08eb0..0009dab 100644 (file)
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -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;

diff --git a/net/core/dst.c b/net/core/dst.c
index 6a3c21b..5cf9617 100644 (file)
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -21,6 +21,7 @@
 #include <linux/sched.h>
 #include <linux/prefetch.h>
 #include <net/lwtunnel.h>
+#include <net/xfrm.h>
 
 #include <net/dst.h>
 #include <net/dst_metadata.h>
@@ -62,7 +63,6 @@ void dst_init(struct dst_entry *dst, struct dst_ops *ops,
              struct net_device *dev, int initial_ref, int initial_obsolete,
              unsigned short flags)
 {
-       dst->child = NULL;
        dst->dev = dev;
        if (dev)
                dev_hold(dev);
@@ -121,8 +121,11 @@ struct dst_entry *dst_destroy(struct dst_entry * dst)
        smp_rmb();
 
 #ifdef CONFIG_XFRM
-       if (dst->xfrm)
-               child = dst->child;
+       if (dst->xfrm) {
+               struct xfrm_dst *xdst = (struct xfrm_dst *) dst;
+
+               child = xdst->child;
+       }
 #endif
        if (!(dst->flags & DST_NOCOUNT))
                dst_entries_add(dst->ops, -1);

diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index f95a150..b9ce241 100644 (file)
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -399,7 +399,7 @@ struct pktgen_dev {
        __u8    ipsmode;                /* IPSEC mode (config) */
        __u8    ipsproto;               /* IPSEC type (config) */
        __u32   spi;
-       struct dst_entry dst;
+       struct xfrm_dst xdst;
        struct dst_ops dstops;
 #endif
        char result[512];
@@ -2609,7 +2609,7 @@ static int pktgen_output_ipsec(struct sk_buff *skb, struct pktgen_dev *pkt_dev)
         * supports both transport/tunnel mode + ESP/AH type.
         */
        if ((x->props.mode == XFRM_MODE_TUNNEL) && (pkt_dev->spi != 0))
-               skb->_skb_refdst = (unsigned long)&pkt_dev->dst | SKB_DST_NOREF;
+               skb->_skb_refdst = (unsigned long)&pkt_dev->xdst.u.dst | SKB_DST_NOREF;
 
        rcu_read_lock_bh();
        err = x->outer_mode->output(x, skb);
@@ -3742,10 +3742,10 @@ static int pktgen_add_device(struct pktgen_thread *t, const char *ifname)
         * performance under such circumstance.
         */
        pkt_dev->dstops.family = AF_INET;
-       pkt_dev->dst.dev = pkt_dev->odev;
-       dst_init_metrics(&pkt_dev->dst, pktgen_dst_metrics, false);
-       pkt_dev->dst.child = &pkt_dev->dst;
-       pkt_dev->dst.ops = &pkt_dev->dstops;
+       pkt_dev->xdst.u.dst.dev = pkt_dev->odev;
+       dst_init_metrics(&pkt_dev->xdst.u.dst, pktgen_dst_metrics, false);
+       pkt_dev->xdst.child = &pkt_dev->xdst.u.dst;
+       pkt_dev->xdst.u.dst.ops = &pkt_dev->dstops;
 #endif
 
        return add_dev_to_thread(t, pkt_dev);

diff --git a/net/netfilter/xt_policy.c b/net/netfilter/xt_policy.c
index 2b4ab18..5639fb0 100644 (file)
--- a/net/netfilter/xt_policy.c
+++ b/net/netfilter/xt_policy.c
@@ -93,7 +93,8 @@ match_policy_out(const struct sk_buff *skb, const struct xt_policy_info *info,
        if (dst->xfrm == NULL)
                return -1;
 
-       for (i = 0; dst && dst->xfrm; dst = dst->child, i++) {
+       for (i = 0; dst && dst->xfrm;
+            dst = ((struct xfrm_dst *)dst)->child, i++) {
                pos = strict ? i : 0;
                if (pos >= info->len)
                        return 0;

diff --git a/net/xfrm/xfrm_device.c b/net/xfrm/xfrm_device.c
index 30e5746..c5851dd 100644 (file)
--- a/net/xfrm/xfrm_device.c
+++ b/net/xfrm/xfrm_device.c
@@ -121,7 +121,7 @@ bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x)
                return false;
 
        if ((x->xso.offload_handle && (dev == dst->path->dev)) &&
-            !dst->child->xfrm && x->type->get_mtu) {
+            !xdst->child->xfrm && x->type->get_mtu) {
                mtu = x->type->get_mtu(x, xdst->child_mtu_cached);
 
                if (skb->len <= mtu)