diff options
| -rw-r--r-- | net/mptcp/protocol.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 8cc9dd2cc828..939a5045181a 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -158,6 +158,27 @@ static void __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk, MPTCP_SKB_CB(skb)->offset = offset; } +/* both sockets must be locked */ +static bool mptcp_subflow_dsn_valid(const struct mptcp_sock *msk, + struct sock *ssk) +{ + struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); + u64 dsn = mptcp_subflow_get_mapped_dsn(subflow); + + /* revalidate data sequence number. + * + * mptcp_subflow_data_available() is usually called + * without msk lock. Its unlikely (but possible) + * that msk->ack_seq has been advanced since the last + * call found in-sequence data. + */ + if (likely(dsn == msk->ack_seq)) + return true; + + subflow->data_avail = 0; + return mptcp_subflow_data_available(ssk); +} + static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk, struct sock *ssk, unsigned int *bytes) @@ -169,6 +190,11 @@ static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk, struct tcp_sock *tp; bool done = false; + if (!mptcp_subflow_dsn_valid(msk, ssk)) { + *bytes = 0; + return false; + } + if (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) { int rcvbuf = max(ssk->sk_rcvbuf, sk->sk_rcvbuf); |