1 files changed, 88 insertions, 0 deletions

diff --git a/net/phonet/socket.c b/net/phonet/socket.c
index 7c91f739f138..4c29a23e9007 100644
--- a/net/phonet/socket.c
+++ b/net/phonet/socket.c
@@ -565,3 +565,91 @@ const struct file_operations pn_sock_seq_fops = {
         .release = seq_release_net,
 };
 #endif
+
+static struct  {
+        struct sock *sk[256];
+} pnres;
+
+/*
+ * Find and hold socket based on resource.
+ */
+struct sock *pn_find_sock_by_res(struct net *net, u8 res)
+{
+        struct sock *sk;
+
+        if (!net_eq(net, &init_net))
+                return NULL;
+
+        rcu_read_lock();
+        sk = rcu_dereference(pnres.sk[res]);
+        if (sk)
+                sock_hold(sk);
+        rcu_read_unlock();
+        return sk;
+}
+
+static DEFINE_MUTEX(resource_mutex);
+
+int pn_sock_bind_res(struct sock *sk, u8 res)
+{
+        int ret = -EADDRINUSE;
+
+        if (!net_eq(sock_net(sk), &init_net))
+                return -ENOIOCTLCMD;
+        if (!capable(CAP_SYS_ADMIN))
+                return -EPERM;
+        if (pn_socket_autobind(sk->sk_socket))
+                return -EAGAIN;
+
+        mutex_lock(&resource_mutex);
+        if (pnres.sk[res] == NULL) {
+                sock_hold(sk);
+                rcu_assign_pointer(pnres.sk[res], sk);
+                ret = 0;
+        }
+        mutex_unlock(&resource_mutex);
+        return ret;
+}
+
+int pn_sock_unbind_res(struct sock *sk, u8 res)
+{
+        int ret = -ENOENT;
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -EPERM;
+
+        mutex_lock(&resource_mutex);
+        if (pnres.sk[res] == sk) {
+                rcu_assign_pointer(pnres.sk[res], NULL);
+                ret = 0;
+        }
+        mutex_unlock(&resource_mutex);
+
+        if (ret == 0) {
+                synchronize_rcu();
+                sock_put(sk);
+        }
+        return ret;
+}
+
+void pn_sock_unbind_all_res(struct sock *sk)
+{
+        unsigned res, match = 0;
+
+        mutex_lock(&resource_mutex);
+        for (res = 0; res < 256; res++) {
+                if (pnres.sk[res] == sk) {
+                        rcu_assign_pointer(pnres.sk[res], NULL);
+                        match++;
+                }
+        }
+        mutex_unlock(&resource_mutex);
+
+        if (match == 0)
+                return;
+        synchronize_rcu();
+        while (match > 0) {
+                sock_put(sk);
+                match--;
+        }
+}