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Diffstat (limited to 'net/mptcp/protocol.c')
-rw-r--r--net/mptcp/protocol.c67
1 files changed, 48 insertions, 19 deletions
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 32ea8d35489a..34dd0e278a82 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -954,7 +954,8 @@ fallback:
pr_debug("block timeout %ld", timeo);
mptcp_wait_data(sk, &timeo);
- if (unlikely(__mptcp_tcp_fallback(msk)))
+ ssock = __mptcp_tcp_fallback(msk);
+ if (unlikely(ssock))
goto fallback;
}
@@ -1262,11 +1263,14 @@ static void mptcp_close(struct sock *sk, long timeout)
lock_sock(sk);
- mptcp_token_destroy(msk->token);
inet_sk_state_store(sk, TCP_CLOSE);
- __mptcp_flush_join_list(msk);
-
+ /* be sure to always acquire the join list lock, to sync vs
+ * mptcp_finish_join().
+ */
+ spin_lock_bh(&msk->join_list_lock);
+ list_splice_tail_init(&msk->join_list, &msk->conn_list);
+ spin_unlock_bh(&msk->join_list_lock);
list_splice_init(&msk->conn_list, &conn_list);
data_fin_tx_seq = msk->write_seq;
@@ -1456,6 +1460,7 @@ static void mptcp_destroy(struct sock *sk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
+ mptcp_token_destroy(msk->token);
if (msk->cached_ext)
__skb_ext_put(msk->cached_ext);
@@ -1622,22 +1627,30 @@ bool mptcp_finish_join(struct sock *sk)
if (!msk->pm.server_side)
return true;
- /* passive connection, attach to msk socket */
+ if (!mptcp_pm_allow_new_subflow(msk))
+ return false;
+
+ /* active connections are already on conn_list, and we can't acquire
+ * msk lock here.
+ * use the join list lock as synchronization point and double-check
+ * msk status to avoid racing with mptcp_close()
+ */
+ spin_lock_bh(&msk->join_list_lock);
+ ret = inet_sk_state_load(parent) == TCP_ESTABLISHED;
+ if (ret && !WARN_ON_ONCE(!list_empty(&subflow->node)))
+ list_add_tail(&subflow->node, &msk->join_list);
+ spin_unlock_bh(&msk->join_list_lock);
+ if (!ret)
+ return false;
+
+ /* attach to msk socket only after we are sure he will deal with us
+ * at close time
+ */
parent_sock = READ_ONCE(parent->sk_socket);
if (parent_sock && !sk->sk_socket)
mptcp_sock_graft(sk, parent_sock);
-
- ret = mptcp_pm_allow_new_subflow(msk);
- if (ret) {
- subflow->map_seq = msk->ack_seq;
-
- /* active connections are already on conn_list */
- spin_lock_bh(&msk->join_list_lock);
- if (!WARN_ON_ONCE(!list_empty(&subflow->node)))
- list_add_tail(&subflow->node, &msk->join_list);
- spin_unlock_bh(&msk->join_list_lock);
- }
- return ret;
+ subflow->map_seq = msk->ack_seq;
+ return true;
}
bool mptcp_sk_is_subflow(const struct sock *sk)
@@ -1711,6 +1724,14 @@ static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr,
int err;
lock_sock(sock->sk);
+ if (sock->state != SS_UNCONNECTED && msk->subflow) {
+ /* pending connection or invalid state, let existing subflow
+ * cope with that
+ */
+ ssock = msk->subflow;
+ goto do_connect;
+ }
+
ssock = __mptcp_socket_create(msk, TCP_SYN_SENT);
if (IS_ERR(ssock)) {
err = PTR_ERR(ssock);
@@ -1725,9 +1746,17 @@ static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr,
mptcp_subflow_ctx(ssock->sk)->request_mptcp = 0;
#endif
+do_connect:
err = ssock->ops->connect(ssock, uaddr, addr_len, flags);
- inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));
- mptcp_copy_inaddrs(sock->sk, ssock->sk);
+ sock->state = ssock->state;
+
+ /* on successful connect, the msk state will be moved to established by
+ * subflow_finish_connect()
+ */
+ if (!err || err == EINPROGRESS)
+ mptcp_copy_inaddrs(sock->sk, ssock->sk);
+ else
+ inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk));
unlock:
release_sock(sock->sk);