mptcp: fix fallback for MP_JOIN subflows (d5824847) · Commits · 戴 / test

net/mptcp/options.c

+25 −7

Original line number	Diff line number	Diff line
		@@ -626,6 +626,12 @@ bool mptcp_established_options(struct sock sk, struct sk_buff skb,
		if (unlikely(mptcp_check_fallback(sk)))
		return false;

		/* prevent adding of any MPTCP related options on reset packet
		* until we support MP_TCPRST/MP_FASTCLOSE
		*/
		if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST))
		return false;

		if (mptcp_established_options_mp(sk, skb, &opt_size, remaining, opts))
		ret = true;
		else if (mptcp_established_options_dss(sk, skb, &opt_size, remaining,
		@@ -676,7 +682,7 @@ bool mptcp_synack_options(const struct request_sock req, unsigned int size,
		return false;
		}

		static bool check_fully_established(struct mptcp_sock msk, struct sock sk,
		static bool check_fully_established(struct mptcp_sock msk, struct sock ssk,
		struct mptcp_subflow_context *subflow,
		struct sk_buff *skb,
		struct mptcp_options_received *mp_opt)
		@@ -693,15 +699,20 @@ static bool check_fully_established(struct mptcp_sock msk, struct sock sk,
		TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq &&
		subflow->mp_join && mp_opt->mp_join &&
		READ_ONCE(msk->pm.server_side))
		tcp_send_ack(sk);
		tcp_send_ack(ssk);
		goto fully_established;
		}

		/* we should process OoO packets before the first subflow is fully
		* established, but not expected for MP_JOIN subflows
		/* we must process OoO packets before the first subflow is fully
		* established. OoO packets are instead a protocol violation
		* for MP_JOIN subflows as the peer must not send any data
		* before receiving the forth ack - cfr. RFC 8684 section 3.2.
		*/
		if (TCP_SKB_CB(skb)->seq != subflow->ssn_offset + 1)
		if (TCP_SKB_CB(skb)->seq != subflow->ssn_offset + 1) {
		if (subflow->mp_join)
		goto reset;
		return subflow->mp_capable;
		}

		if (mp_opt->dss && mp_opt->use_ack) {
		/* subflows are fully established as soon as we get any
		@@ -713,9 +724,12 @@ static bool check_fully_established(struct mptcp_sock msk, struct sock sk,
		}

		/* If the first established packet does not contain MP_CAPABLE + data
		* then fallback to TCP
		* then fallback to TCP. Fallback scenarios requires a reset for
		* MP_JOIN subflows.
		*/
		if (!mp_opt->mp_capable) {
		if (subflow->mp_join)
		goto reset;
		subflow->mp_capable = 0;
		pr_fallback(msk);
		__mptcp_do_fallback(msk);
		@@ -732,12 +746,16 @@ fully_established:

		subflow->pm_notified = 1;
		if (subflow->mp_join) {
		clear_3rdack_retransmission(sk);
		clear_3rdack_retransmission(ssk);
		mptcp_pm_subflow_established(msk, subflow);
		} else {
		mptcp_pm_fully_established(msk);
		}
		return true;

		reset:
		mptcp_subflow_reset(ssk);
		return false;
		}

		static u64 expand_ack(u64 old_ack, u64 cur_ack, bool use_64bit)

net/mptcp/protocol.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -348,6 +348,7 @@ void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow,
		struct mptcp_options_received *mp_opt);
		bool mptcp_subflow_data_available(struct sock *sk);
		void __init mptcp_subflow_init(void);
		void mptcp_subflow_reset(struct sock *ssk);

		/* called with sk socket lock held */
		int __mptcp_subflow_connect(struct sock *sk, int ifindex,

net/mptcp/subflow.c

+8 −2

Original line number	Diff line number	Diff line
		@@ -270,6 +270,13 @@ static bool subflow_thmac_valid(struct mptcp_subflow_context *subflow)
		return thmac == subflow->thmac;
		}

		void mptcp_subflow_reset(struct sock *ssk)
		{
		tcp_set_state(ssk, TCP_CLOSE);
		tcp_send_active_reset(ssk, GFP_ATOMIC);
		tcp_done(ssk);
		}

		static void subflow_finish_connect(struct sock sk, const struct sk_buff skb)
		{
		struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
		@@ -342,8 +349,7 @@ fallback:
		return;

		do_reset:
		tcp_send_active_reset(sk, GFP_ATOMIC);
		tcp_done(sk);
		mptcp_subflow_reset(sk);
		}

		struct request_sock_ops mptcp_subflow_request_sock_ops;

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