[PATCH net-next v2 4/5] tcp: rstreason: handle timewait cases in the receive path

[Jason Xing <kerneljasonxing@gmail.com>]

From: Jason Xing <kernelxing@tencent.com>

There are two possible cases where TCP layer can send an RST. Since they
happen in the same place, I think using one independent reason is enough
to identify this special situation.

Signed-off-by: Jason Xing <kernelxing@tencent.com>
---
 include/net/rstreason.h | 5 +++++
 net/ipv4/tcp_ipv4.c     | 2 +-
 net/ipv6/tcp_ipv6.c     | 2 +-
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/include/net/rstreason.h b/include/net/rstreason.h
index fc1b99702771..7ae5bb55559b 100644
--- a/include/net/rstreason.h
+++ b/include/net/rstreason.h
@@ -15,6 +15,7 @@
 	FN(TCP_FLAGS)			\
 	FN(TCP_OLD_ACK)			\
 	FN(TCP_ABORT_ON_DATA)		\
+	FN(TCP_TIMEWAIT_SOCKET)		\
 	FN(MPTCP_RST_EUNSPEC)		\
 	FN(MPTCP_RST_EMPTCP)		\
 	FN(MPTCP_RST_ERESOURCE)		\
@@ -72,6 +73,10 @@ enum sk_rst_reason {
 	 */
 	SK_RST_REASON_TCP_ABORT_ON_DATA,
 
+	/* Here start with the independent reasons */
+	/** @SK_RST_REASON_TCP_TIMEWAIT_SOCKET: happen on the timewait socket */
+	SK_RST_REASON_TCP_TIMEWAIT_SOCKET,
+
 	/* Copy from include/uapi/linux/mptcp.h.
 	 * These reset fields will not be changed since they adhere to
 	 * RFC 8684. So do not touch them. I'm going to list each definition
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 108a438dc247..30ef0c8f5e92 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2427,7 +2427,7 @@ int tcp_v4_rcv(struct sk_buff *skb)
 		tcp_v4_timewait_ack(sk, skb);
 		break;
 	case TCP_TW_RST:
-		tcp_v4_send_reset(sk, skb, sk_rst_convert_drop_reason(drop_reason));
+		tcp_v4_send_reset(sk, skb, SK_RST_REASON_TCP_TIMEWAIT_SOCKET);
 		inet_twsk_deschedule_put(inet_twsk(sk));
 		goto discard_it;
 	case TCP_TW_SUCCESS:;
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 7f6693e794bd..4c3605485b68 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1999,7 +1999,7 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
 		tcp_v6_timewait_ack(sk, skb);
 		break;
 	case TCP_TW_RST:
-		tcp_v6_send_reset(sk, skb, sk_rst_convert_drop_reason(drop_reason));
+		tcp_v6_send_reset(sk, skb, SK_RST_REASON_TCP_TIMEWAIT_SOCKET);
 		inet_twsk_deschedule_put(inet_twsk(sk));
 		goto discard_it;
 	case TCP_TW_SUCCESS:
-- 
2.37.3