mptcp: introducing a helper into active reset logic

JIRA: https://issues.redhat.com/browse/RHEL-48648
Upstream Status: linux.git
Conflicts:\
- Context difference due to missing upstream commit d5dfbfa
  ("mptcp: drop duplicate header inclusions") in c9s.

commit 215d402
Author: Jason Xing <kernelxing@tencent.com>
Date:   Thu Apr 25 11:13:39 2024 +0800

    mptcp: introducing a helper into active reset logic

    Since we have mapped every mptcp reset reason definition in enum
    sk_rst_reason, introducing a new helper can cover some missing places
    where we have already set the subflow->reset_reason.

    Note: using SK_RST_REASON_NOT_SPECIFIED is the same as
    SK_RST_REASON_MPTCP_RST_EUNSPEC. They are both unknown. So we can convert
    it directly.

    Suggested-by: Paolo Abeni <pabeni@redhat.com>
    Signed-off-by: Jason Xing <kernelxing@tencent.com>
    Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
    Reviewed-by: Eric Dumazet <edumazet@google.com>
    Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Signed-off-by: Antoine Tenart <atenart@redhat.com>

Author: atenart

net/mptcp/protocol.c

@@ -22,7 +22,6 @@
 #endif
 #include <net/mptcp.h>
 #include <net/xfrm.h>
-#include <net/rstreason.h>
 #include <asm/ioctls.h>
 #include "protocol.h"
 #include "mib.h"
@@ -2567,8 +2566,7 @@ static void mptcp_check_fastclose(struct mptcp_sock *msk)
 
 		slow = lock_sock_fast(tcp_sk);
 		if (tcp_sk->sk_state != TCP_CLOSE) {
-			tcp_send_active_reset(tcp_sk, GFP_ATOMIC,
-					      SK_RST_REASON_NOT_SPECIFIED);
+			mptcp_send_active_reset_reason(tcp_sk);
 			tcp_set_state(tcp_sk, TCP_CLOSE);
 		}
 		unlock_sock_fast(tcp_sk, slow);

net/mptcp/protocol.h

@@ -12,6 +12,7 @@
 #include <net/inet_connection_sock.h>
 #include <uapi/linux/mptcp.h>
 #include <net/genetlink.h>
+#include <net/rstreason.h>
 
 #include "mptcp_pm_gen.h"
 
@@ -603,6 +604,16 @@ sk_rst_convert_mptcp_reason(u32 reason)
 	}
 }
 
+static inline void
+mptcp_send_active_reset_reason(struct sock *sk)
+{
+	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+	enum sk_rst_reason reason;
+
+	reason = sk_rst_convert_mptcp_reason(subflow->reset_reason);
+	tcp_send_active_reset(sk, GFP_ATOMIC, reason);
+}
+
 static inline u64
 mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow)
 {

net/mptcp/subflow.c

@@ -22,7 +22,6 @@
 #endif
 #include <net/mptcp.h>
 #include <uapi/linux/mptcp.h>
-#include <net/rstreason.h>
 
 #include "protocol.h"
 #include "mib.h"
@@ -419,7 +418,7 @@ void mptcp_subflow_reset(struct sock *ssk)
 	/* must hold: tcp_done() could drop last reference on parent */
 	sock_hold(sk);
 
-	tcp_send_active_reset(ssk, GFP_ATOMIC, SK_RST_REASON_NOT_SPECIFIED);
+	mptcp_send_active_reset_reason(ssk);
 	tcp_done(ssk);
 	if (!test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &mptcp_sk(sk)->flags))
 		mptcp_schedule_work(sk);
@@ -1352,8 +1351,7 @@ static bool subflow_check_data_avail(struct sock *ssk)
 			tcp_set_state(ssk, TCP_CLOSE);
 			while ((skb = skb_peek(&ssk->sk_receive_queue)))
 				sk_eat_skb(ssk, skb);
-			tcp_send_active_reset(ssk, GFP_ATOMIC,
-					      SK_RST_REASON_NOT_SPECIFIED);
+			mptcp_send_active_reset_reason(ssk);
 			WRITE_ONCE(subflow->data_avail, false);
 			return false;
 		}