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From: Geliang Tang <geliangtang@gmail.com>
To: mptcp@lists.linux.dev
Cc: Geliang Tang <geliangtang@gmail.com>
Subject: [MPTCP][PATCH v4 mptcp-next 3/5] mptcp: send out MP_FAIL when data checksum fail
Date: Wed, 14 Jul 2021 18:41:55 +0800	[thread overview]
Message-ID: <779edc1afc2f4622d9cffbdf3f8ccccfcdfd33cb.1626258797.git.geliangtang@gmail.com> (raw)
In-Reply-To: <c9b00f7ce8d17ea4fb6e60c09433f36cc144a2f7.1626258797.git.geliangtang@gmail.com>

When a bad checksum is detected, set the send_mp_fail flag to send out
the MP_FAIL option.

Add a new function mptcp_has_another_subflow() to check whether there's
only a single subflow.

When multiple subflows are in use, close the affected subflow with a RST
that includes an MP_FAIL option and discard the data with the bad
checksum.

Set the sk_state of the subsocket to TCP_CLOSE, then the flag
MPTCP_WORK_CLOSE_SUBFLOW will be set in subflow_sched_work_if_closed,
and the subflow will be closed.

Signed-off-by: Geliang Tang <geliangtang@gmail.com>
---
 net/mptcp/protocol.h | 13 +++++++++++++
 net/mptcp/subflow.c  | 15 +++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 20f8faf0543b..260920d26935 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -601,6 +601,19 @@ static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
 	inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
 }
 
+static inline bool mptcp_has_another_subflow(struct sock *ssk)
+{
+	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk), *tmp;
+	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
+
+	mptcp_for_each_subflow(msk, tmp) {
+		if (tmp != subflow)
+			return true;
+	}
+
+	return false;
+}
+
 void __init mptcp_proto_init(void);
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 int __init mptcp_proto_v6_init(void);
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 966f777d35ce..11a719fad718 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -908,6 +908,7 @@ static enum mapping_status validate_data_csum(struct sock *ssk, struct sk_buff *
 	csum = csum_partial(&header, sizeof(header), subflow->map_data_csum);
 	if (unlikely(csum_fold(csum))) {
 		MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DATACSUMERR);
+		subflow->send_mp_fail = 1;
 		return subflow->mp_join ? MAPPING_INVALID : MAPPING_DUMMY;
 	}
 
@@ -1155,6 +1156,20 @@ static bool subflow_check_data_avail(struct sock *ssk)
 
 fallback:
 	/* RFC 8684 section 3.7. */
+	if (subflow->send_mp_fail) {
+		if (mptcp_has_another_subflow(ssk)) {
+			ssk->sk_err = EBADMSG;
+			tcp_set_state(ssk, TCP_CLOSE);
+			subflow->reset_transient = 0;
+			subflow->reset_reason = MPTCP_RST_EMIDDLEBOX;
+			tcp_send_active_reset(ssk, GFP_ATOMIC);
+			while ((skb = skb_peek(&ssk->sk_receive_queue)))
+				sk_eat_skb(ssk, skb);
+			WRITE_ONCE(subflow->data_avail, 0);
+			return true;
+		}
+	}
+
 	if (subflow->mp_join || subflow->fully_established) {
 		/* fatal protocol error, close the socket.
 		 * subflow_error_report() will introduce the appropriate barriers
-- 
2.31.1


  reply	other threads:[~2021-07-14 10:42 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-14 10:41 [MPTCP][PATCH v4 mptcp-next 0/5] MP_FAIL support Geliang Tang
2021-07-14 10:41 ` [MPTCP][PATCH v4 mptcp-next 1/5] mptcp: MP_FAIL suboption sending Geliang Tang
2021-07-14 10:41   ` [MPTCP][PATCH v4 mptcp-next 2/5] mptcp: MP_FAIL suboption receiving Geliang Tang
2021-07-14 10:41     ` Geliang Tang [this message]
2021-07-14 10:41       ` [MPTCP][PATCH v4 mptcp-next 4/5] mptcp: add the mibs for MP_FAIL Geliang Tang
2021-07-14 10:41         ` [MPTCP][PATCH v4 mptcp-next 5/5] selftests: mptcp: add MP_FAIL mibs check Geliang Tang
2021-07-15  1:46       ` [MPTCP][PATCH v4 mptcp-next 3/5] mptcp: send out MP_FAIL when data checksum fail Mat Martineau

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