Bluetooth: Add support for deferring RFCOMM connection setup

In order to decide if listening RFCOMM sockets should be accept()ed
the BD_ADDR of the remote device needs to be known. This patch adds
a socket option which defines a timeout for deferring the actual
connection setup.

The connection setup is done after reading from the socket for the
first time. Until then writing to the socket returns ENOTCONN.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

1 files changed, 43 insertions, 1 deletions

diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index 65dd7133d72b..d37a829a81e4 100644
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -262,8 +262,10 @@ static void rfcomm_sock_init(struct sock *sk, struct sock *parent)
         if (parent) {
                 sk->sk_type = parent->sk_type;
                 pi->link_mode = rfcomm_pi(parent)->link_mode;
+                pi->dlc->defer_setup = bt_sk(parent)->defer_setup;
         } else {
                 pi->link_mode = 0;
+                pi->dlc->defer_setup = 0;
         }
 
         pi->dlc->link_mode = pi->link_mode;
@@ -554,6 +556,9 @@ static int rfcomm_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
         struct sk_buff *skb;
         int sent = 0;
 
+        if (test_bit(RFCOMM_DEFER_SETUP, &d->flags))
+                return -ENOTCONN;
+
         if (msg->msg_flags & MSG_OOB)
                 return -EOPNOTSUPP;
 
@@ -633,10 +638,16 @@ static int rfcomm_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
                                struct msghdr *msg, size_t size, int flags)
 {
         struct sock *sk = sock->sk;
+        struct rfcomm_dlc *d = rfcomm_pi(sk)->dlc;
         int err = 0;
         size_t target, copied = 0;
         long timeo;
 
+        if (test_and_clear_bit(RFCOMM_DEFER_SETUP, &d->flags)) {
+                rfcomm_dlc_accept(d);
+                return 0;
+        }
+
         if (flags & MSG_OOB)
                 return -EOPNOTSUPP;
 
@@ -746,6 +757,7 @@ static int rfcomm_sock_setsockopt(struct socket *sock, int level, int optname, c
 {
         struct sock *sk = sock->sk;
         int err = 0;
+        u32 opt;
 
         BT_DBG("sk %p", sk);
 
@@ -755,6 +767,20 @@ static int rfcomm_sock_setsockopt(struct socket *sock, int level, int optname, c
         lock_sock(sk);
 
         switch (optname) {
+        case BT_DEFER_SETUP:
+                if (sk->sk_state != BT_BOUND && sk->sk_state != BT_LISTEN) {
+                        err = -EINVAL;
+                        break;
+                }
+
+                if (get_user(opt, (u32 __user *) optval)) {
+                        err = -EFAULT;
+                        break;
+                }
+
+                bt_sk(sk)->defer_setup = opt;
+                break;
+
         default:
                 err = -ENOPROTOOPT;
                 break;
@@ -785,7 +811,8 @@ static int rfcomm_sock_getsockopt_old(struct socket *sock, int optname, char __u
                 break;
 
         case RFCOMM_CONNINFO:
-                if (sk->sk_state != BT_CONNECTED) {
+                if (sk->sk_state != BT_CONNECTED &&
+                                        !rfcomm_pi(sk)->dlc->defer_setup) {
                         err = -ENOTCONN;
                         break;
                 }
@@ -826,6 +853,17 @@ static int rfcomm_sock_getsockopt(struct socket *sock, int level, int optname, c
         lock_sock(sk);
 
         switch (optname) {
+        case BT_DEFER_SETUP:
+                if (sk->sk_state != BT_BOUND && sk->sk_state != BT_LISTEN) {
+                        err = -EINVAL;
+                        break;
+                }
+
+                if (put_user(bt_sk(sk)->defer_setup, (u32 __user *) optval))
+                        err = -EFAULT;
+
+                break;
+
         default:
                 err = -ENOPROTOOPT;
                 break;
@@ -938,6 +976,10 @@ int rfcomm_connect_ind(struct rfcomm_session *s, u8 channel, struct rfcomm_dlc *
 
 done:
         bh_unlock_sock(parent);
+
+        if (bt_sk(parent)->defer_setup)
+                parent->sk_state_change(parent);
+
         return result;
 }