net: skb->dst accessors

Define three accessors to get/set dst attached to a skb

struct dst_entry *skb_dst(const struct sk_buff *skb)

void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)

void skb_dst_drop(struct sk_buff *skb)
This one should replace occurrences of :
dst_release(skb->dst)
skb->dst = NULL;

Delete skb->dst field

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 25 insertions, 10 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index a3ae3c525833..9ef6eb20247b 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -323,7 +323,6 @@ struct sk_buff {
         struct net_device       *dev;
 
         union {
-                struct  dst_entry       *dst;
                 unsigned long           _skb_dst;
         };
 #ifdef CONFIG_XFRM
@@ -426,9 +425,19 @@ extern void skb_dma_unmap(struct device *dev, struct sk_buff *skb,
                           enum dma_data_direction dir);
 #endif
 
+static inline struct dst_entry *skb_dst(const struct sk_buff *skb)
+{
+        return (struct dst_entry *)skb->_skb_dst;
+}
+
+static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
+{
+        skb->_skb_dst = (unsigned long)dst;
+}
+
 static inline struct rtable *skb_rtable(const struct sk_buff *skb)
 {
-        return (struct rtable *)skb->_skb_dst;
+        return (struct rtable *)skb_dst(skb);
 }
 
 extern void kfree_skb(struct sk_buff *skb);
diff --git a/include/net/dst.h b/include/net/dst.h
index 6be3b082a070..7fc409c19b37 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -195,6 +195,12 @@ struct dst_entry * dst_clone(struct dst_entry * dst)
 }
 
 extern void dst_release(struct dst_entry *dst);
+static inline void skb_dst_drop(struct sk_buff *skb)
+{
+        if (skb->_skb_dst)
+                dst_release(skb_dst(skb));
+        skb->_skb_dst = 0UL;
+}
 
 /* Children define the path of the packet through the
  * Linux networking.  Thus, destinations are stackable.
@@ -246,7 +252,7 @@ static inline void dst_negative_advice(struct dst_entry **dst_p)
 
 static inline void dst_link_failure(struct sk_buff *skb)
 {
-        struct dst_entry * dst = skb->dst;
+        struct dst_entry *dst = skb_dst(skb);
         if (dst && dst->ops && dst->ops->link_failure)
                 dst->ops->link_failure(skb);
 }
@@ -265,13 +271,13 @@ static inline void dst_set_expires(struct dst_entry *dst, int timeout)
 /* Output packet to network from transport.  */
 static inline int dst_output(struct sk_buff *skb)
 {
-        return skb->dst->output(skb);
+        return skb_dst(skb)->output(skb);
 }
 
 /* Input packet from network to transport.  */
 static inline int dst_input(struct sk_buff *skb)
 {
-        return skb->dst->input(skb);
+        return skb_dst(skb)->input(skb);
 }
 
 static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
diff --git a/include/net/inet6_hashtables.h b/include/net/inet6_hashtables.h
index f74665d7bea8..22c73a77cd99 100644
--- a/include/net/inet6_hashtables.h
+++ b/include/net/inet6_hashtables.h
@@ -100,7 +100,7 @@ static inline struct sock *__inet6_lookup_skb(struct inet_hashinfo *hashinfo,
 
         if (unlikely(sk = skb_steal_sock(skb)))
                 return sk;
-        else return __inet6_lookup(dev_net(skb->dst->dev), hashinfo,
+        else return __inet6_lookup(dev_net(skb_dst(skb)->dev), hashinfo,
                                    &ipv6_hdr(skb)->saddr, sport,
                                    &ipv6_hdr(skb)->daddr, ntohs(dport),
                                    inet6_iif(skb));
diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index a44e2248b2ef..d522dcf3031a 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -385,7 +385,7 @@ static inline struct sock *__inet_lookup_skb(struct inet_hashinfo *hashinfo,
         if (unlikely(sk = skb_steal_sock(skb)))
                 return sk;
         else
-                return __inet_lookup(dev_net(skb->dst->dev), hashinfo,
+                return __inet_lookup(dev_net(skb_dst(skb)->dev), hashinfo,
                                      iph->saddr, sport,
                                      iph->daddr, dport, inet_iif(skb));
 }
diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h
index 5f53db7e4e57..0e1b8aebaff8 100644
--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h
@@ -142,7 +142,7 @@ static inline void ip6_dst_store(struct sock *sk, struct dst_entry *dst,
 
 static inline int ipv6_unicast_destination(struct sk_buff *skb)
 {
-        struct rt6_info *rt = (struct rt6_info *) skb->dst;
+        struct rt6_info *rt = (struct rt6_info *) skb_dst(skb);
 
         return rt->rt6i_flags & RTF_LOCAL;
 }
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 2e9f5c0018ae..736bca450886 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -994,7 +994,7 @@ static inline int __xfrm_policy_check2(struct sock *sk, int dir,
                 return __xfrm_policy_check(sk, ndir, skb, family);
 
         return  (!net->xfrm.policy_count[dir] && !skb->sp) ||
-                (skb->dst->flags & DST_NOPOLICY) ||
+                (skb_dst(skb)->flags & DST_NOPOLICY) ||
                 __xfrm_policy_check(sk, ndir, skb, family);
 }
 
@@ -1048,7 +1048,7 @@ static inline int xfrm_route_forward(struct sk_buff *skb, unsigned short family)
         struct net *net = dev_net(skb->dev);
 
         return  !net->xfrm.policy_count[XFRM_POLICY_OUT] ||
-                (skb->dst->flags & DST_NOXFRM) ||
+                (skb_dst(skb)->flags & DST_NOXFRM) ||
                 __xfrm_route_forward(skb, family);
 }