[SOCK]: Introduce sk_clone

Out of tcp_create_openreq_child, will be used in
dccp_create_openreq_child, and is a nice sock function anyway.

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 74 insertions, 0 deletions

diff --git a/net/core/sock.c b/net/core/sock.c
index aba31fedf2ac..ccd10fd65682 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -700,6 +700,80 @@ void sk_free(struct sock *sk)
         module_put(owner);
 }
 
+struct sock *sk_clone(const struct sock *sk, const unsigned int __nocast priority)
+{
+        struct sock *newsk = sk_alloc(sk->sk_family, priority, sk->sk_prot, 0);
+
+        if (newsk != NULL) {
+                struct sk_filter *filter;
+
+                memcpy(newsk, sk, sk->sk_prot->obj_size);
+
+                /* SANITY */
+                sk_node_init(&newsk->sk_node);
+                sock_lock_init(newsk);
+                bh_lock_sock(newsk);
+
+                atomic_set(&newsk->sk_rmem_alloc, 0);
+                atomic_set(&newsk->sk_wmem_alloc, 0);
+                atomic_set(&newsk->sk_omem_alloc, 0);
+                skb_queue_head_init(&newsk->sk_receive_queue);
+                skb_queue_head_init(&newsk->sk_write_queue);
+
+                rwlock_init(&newsk->sk_dst_lock);
+                rwlock_init(&newsk->sk_callback_lock);
+
+                newsk->sk_dst_cache     = NULL;
+                newsk->sk_wmem_queued   = 0;
+                newsk->sk_forward_alloc = 0;
+                newsk->sk_send_head     = NULL;
+                newsk->sk_backlog.head  = newsk->sk_backlog.tail = NULL;
+                newsk->sk_userlocks     = sk->sk_userlocks & ~SOCK_BINDPORT_LOCK;
+
+                sock_reset_flag(newsk, SOCK_DONE);
+                skb_queue_head_init(&newsk->sk_error_queue);
+
+                filter = newsk->sk_filter;
+                if (filter != NULL)
+                        sk_filter_charge(newsk, filter);
+
+                if (unlikely(xfrm_sk_clone_policy(newsk))) {
+                        /* It is still raw copy of parent, so invalidate
+                         * destructor and make plain sk_free() */
+                        newsk->sk_destruct = NULL;
+                        sk_free(newsk);
+                        newsk = NULL;
+                        goto out;
+                }
+
+                newsk->sk_err      = 0;
+                newsk->sk_priority = 0;
+                atomic_set(&newsk->sk_refcnt, 2);
+
+                /*
+                 * Increment the counter in the same struct proto as the master
+                 * sock (sk_refcnt_debug_inc uses newsk->sk_prot->socks, that
+                 * is the same as sk->sk_prot->socks, as this field was copied
+                 * with memcpy).
+                 *
+                 * This _changes_ the previous behaviour, where
+                 * tcp_create_openreq_child always was incrementing the
+                 * equivalent to tcp_prot->socks (inet_sock_nr), so this have
+                 * to be taken into account in all callers. -acme
+                 */
+                sk_refcnt_debug_inc(newsk);
+                newsk->sk_socket = NULL;
+                newsk->sk_sleep  = NULL;
+
+                if (newsk->sk_prot->sockets_allocated)
+                        atomic_inc(newsk->sk_prot->sockets_allocated);
+        }
+out:
+        return newsk;
+}
+
+EXPORT_SYMBOL_GPL(sk_clone);
+
 void __init sk_init(void)
 {
         if (num_physpages <= 4096) {