subflow: introduce and use mptcp_can_accept_new_subflow()

So that we can easily perform some basic PM-related
adimission checks before creating the child socket.

Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Tested-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Paolo Abeni 2020-07-23 13:02:36 +02:00 committed by David S. Miller
parent 97e617518c
commit 4cf8b7e48a

View File

@ -53,6 +53,12 @@ static void subflow_generate_hmac(u64 key1, u64 key2, u32 nonce1, u32 nonce2,
mptcp_crypto_hmac_sha(key1, key2, msg, 8, hmac);
}
static bool mptcp_can_accept_new_subflow(const struct mptcp_sock *msk)
{
return mptcp_is_fully_established((void *)msk) &&
READ_ONCE(msk->pm.accept_subflow);
}
/* validate received token and create truncated hmac and nonce for SYN-ACK */
static struct mptcp_sock *subflow_token_join_request(struct request_sock *req,
const struct sk_buff *skb)
@ -443,6 +449,7 @@ create_msk:
} else if (subflow_req->mp_join) {
mptcp_get_options(skb, &mp_opt);
if (!mp_opt.mp_join ||
!mptcp_can_accept_new_subflow(subflow_req->msk) ||
!subflow_hmac_valid(req, &mp_opt)) {
SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKMAC);
fallback = true;