mptcp: implement support for user-space disconnect

Handle explicitly AF_UNSPEC in mptcp_stream_connnect() to
allow user-space to disconnect established MPTCP connections

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 628cd60..667e153 100644 (file)
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -3404,9 +3404,20 @@ static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr,
        struct mptcp_sock *msk = mptcp_sk(sock->sk);
        struct mptcp_subflow_context *subflow;
        struct socket *ssock;
-       int err;
+       int err = -EINVAL;
 
        lock_sock(sock->sk);
+       if (uaddr) {
+               if (addr_len < sizeof(uaddr->sa_family))
+                       goto unlock;
+
+               if (uaddr->sa_family == AF_UNSPEC) {
+                       err = mptcp_disconnect(sock->sk, flags);
+                       sock->state = err ? SS_DISCONNECTING : SS_UNCONNECTED;
+                       goto unlock;
+               }
+       }
+
        if (sock->state != SS_UNCONNECTED && msk->subflow) {
                /* pending connection or invalid state, let existing subflow
                 * cope with that
@@ -3416,10 +3427,8 @@ static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr,
        }
 
        ssock = __mptcp_nmpc_socket(msk);
-       if (!ssock) {
-               err = -EINVAL;
+       if (!ssock)
                goto unlock;
-       }
 
        mptcp_token_destroy(msk);
        inet_sk_state_store(sock->sk, TCP_SYN_SENT);