sock: add sk_dst_pending_confirm flag

Add new sock flag to allow sockets to confirm neighbour.
When same struct dst_entry can be used for many different
neighbours we can not use it for pending confirmations.
As not all call paths lock the socket use full word for
the flag.

Add sk_dst_confirm as replacement for dst_confirm when
called for received packets.

Signed-off-by: Julian Anastasov <ja@ssi.bg>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/sock.h b/include/net/sock.h
index 94e65fd703548dd40e16c30207fd55c879ed0b60..85d856b94b4b949dc8377cf49a9114b957e39bcb 100644 (file)
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -240,6 +240,7 @@ struct sock_common {
   *    @sk_wq: sock wait queue and async head
   *    @sk_rx_dst: receive input route used by early demux
   *    @sk_dst_cache: destination cache
+  *    @sk_dst_pending_confirm: need to confirm neighbour
   *    @sk_policy: flow policy
   *    @sk_receive_queue: incoming packets
   *    @sk_wmem_alloc: transmit queue bytes committed
@@ -393,6 +394,8 @@ struct sock {
        struct sk_buff_head     sk_write_queue;
        __s32                   sk_peek_off;
        int                     sk_write_pending;
+       __u32                   sk_dst_pending_confirm;
+       /* Note: 32bit hole on 64bit arches */
        long                    sk_sndtimeo;
        struct timer_list       sk_timer;
        __u32                   sk_priority;
@@ -1764,6 +1767,7 @@ static inline void dst_negative_advice(struct sock *sk)
                if (ndst != dst) {
                        rcu_assign_pointer(sk->sk_dst_cache, ndst);
                        sk_tx_queue_clear(sk);
+                       sk->sk_dst_pending_confirm = 0;
                }
        }
 }
@@ -1774,6 +1778,7 @@ __sk_dst_set(struct sock *sk, struct dst_entry *dst)
        struct dst_entry *old_dst;
 
        sk_tx_queue_clear(sk);
+       sk->sk_dst_pending_confirm = 0;
        /*
         * This can be called while sk is owned by the caller only,
         * with no state that can be checked in a rcu_dereference_check() cond
@@ -1789,6 +1794,7 @@ sk_dst_set(struct sock *sk, struct dst_entry *dst)
        struct dst_entry *old_dst;
 
        sk_tx_queue_clear(sk);
+       sk->sk_dst_pending_confirm = 0;
        old_dst = xchg((__force struct dst_entry **)&sk->sk_dst_cache, dst);
        dst_release(old_dst);
 }
@@ -1809,6 +1815,12 @@ struct dst_entry *__sk_dst_check(struct sock *sk, u32 cookie);
 
 struct dst_entry *sk_dst_check(struct sock *sk, u32 cookie);
 
+static inline void sk_dst_confirm(struct sock *sk)
+{
+       if (!sk->sk_dst_pending_confirm)
+               sk->sk_dst_pending_confirm = 1;
+}
+
 bool sk_mc_loop(struct sock *sk);
 
 static inline bool sk_can_gso(const struct sock *sk)

diff --git a/net/core/sock.c b/net/core/sock.c
index 8b35debfe454e3fa0ab2b320d6df7a016ff9c130..b74356535559cb763f8fa40489b0936a1fea6c15 100644 (file)
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -502,6 +502,7 @@ struct dst_entry *__sk_dst_check(struct sock *sk, u32 cookie)
 
        if (dst && dst->obsolete && dst->ops->check(dst, cookie) == NULL) {
                sk_tx_queue_clear(sk);
+               sk->sk_dst_pending_confirm = 0;
                RCU_INIT_POINTER(sk->sk_dst_cache, NULL);
                dst_release(dst);
                return NULL;
@@ -1519,6 +1520,7 @@ struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority)
                                af_family_clock_key_strings[newsk->sk_family]);
 
                newsk->sk_dst_cache     = NULL;
+               newsk->sk_dst_pending_confirm = 0;
                newsk->sk_wmem_queued   = 0;
                newsk->sk_forward_alloc = 0;
                atomic_set(&newsk->sk_drops, 0);