mptcp: pass right struct to subflow_hmac_valid

subflow_hmac_valid() needs to access the MPTCP socket and the subflow
request, but not the request sock that is passed in argument.

Instead, the subflow request can be directly passed to avoid getting it
via an additional cast.

Signed-off-by: Matthieu Baerts (NGI0) <[email protected]>

Author: matttbe

net/mptcp/subflow.c

@@ -745,15 +745,11 @@ struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *op
 EXPORT_SYMBOL(mptcp_subflow_reqsk_alloc);
 
 /* validate hmac received in third ACK */
-static bool subflow_hmac_valid(const struct request_sock *req,
+static bool subflow_hmac_valid(const struct mptcp_subflow_request_sock *subflow_req,
 			       const struct mptcp_options_received *mp_opt)
 {
-	const struct mptcp_subflow_request_sock *subflow_req;
+	struct mptcp_sock *msk = subflow_req->msk;
 	u8 hmac[SHA256_DIGEST_SIZE];
-	struct mptcp_sock *msk;
-
-	subflow_req = mptcp_subflow_rsk(req);
-	msk = subflow_req->msk;
 
 	subflow_generate_hmac(READ_ONCE(msk->remote_key),
 			      READ_ONCE(msk->local_key),
@@ -899,7 +895,7 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
 				goto dispose_child;
 			}
 
-			if (!subflow_hmac_valid(req, &mp_opt)) {
+			if (!subflow_hmac_valid(subflow_req, &mp_opt)) {
 				SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKMAC);
 				subflow_add_reset_reason(skb, MPTCP_RST_EPROHIBIT);
 				goto dispose_child;