Commit 25010bfd authored by Paolo Abeni's avatar Paolo Abeni
Browse files

Merge branch 'mptcp-fix-duplicate-data-handling' 



Matthieu Baerts says:

====================
mptcp: fix duplicate data handling

In some cases, the subflow-level's copied_seq counter was incorrectly
increased, leading to an unexpected subflow reset.

Patch 1/2 fixes the RCVPRUNED MIB counter that was attached to the wrong
event since its introduction in v5.14, backported to v5.11.

Patch 2/2 fixes the copied_seq counter issues, is present since v5.10.

Signed-off-by: default avatarMatthieu Baerts (NGI0) <matttbe@kernel.org>
====================

Link: https://patch.msgid.link/20240731-upstream-net-20240731-mptcp-dup-data-v1-0-bde833fa628a@kernel.org


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parents 2b4a32da 68cc9247

net/mptcp/protocol.c

+4 −4
Original line number Diff line number Diff line
@@ -350,8 +350,10 @@ static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk, 
	skb_orphan(skb);



	/* try to fetch required memory from subflow */

	if (!mptcp_rmem_schedule(sk, ssk, skb->truesize))

	if (!mptcp_rmem_schedule(sk, ssk, skb->truesize)) {

		MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED);

		goto drop;

	}



	has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp;
@@ -844,10 +846,8 @@ void mptcp_data_ready(struct sock *sk, struct sock *ssk) 
		sk_rbuf = ssk_rbuf;



	/* over limit? can't append more skbs to msk, Also, no need to wake-up*/

	if (__mptcp_rmem(sk) > sk_rbuf) {

		MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED);

	if (__mptcp_rmem(sk) > sk_rbuf)

		return;

	}



	/* Wake-up the reader only for in-sequence data */

	mptcp_data_lock(sk);

net/mptcp/subflow.c

+12 −4
Original line number Diff line number Diff line
@@ -1230,14 +1230,22 @@ static void mptcp_subflow_discard_data(struct sock *ssk, struct sk_buff *skb, 
{

	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);

	bool fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;

	u32 incr;

	struct tcp_sock *tp = tcp_sk(ssk);

	u32 offset, incr, avail_len;



	incr = limit >= skb->len ? skb->len + fin : limit;

	offset = tp->copied_seq - TCP_SKB_CB(skb)->seq;

	if (WARN_ON_ONCE(offset > skb->len))

		goto out;



	avail_len = skb->len - offset;

	incr = limit >= avail_len ? avail_len + fin : limit;



	pr_debug("discarding=%d len=%d seq=%d", incr, skb->len,

		 subflow->map_subflow_seq);

	pr_debug("discarding=%d len=%d offset=%d seq=%d", incr, skb->len,

		 offset, subflow->map_subflow_seq);

	MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DUPDATA);

	tcp_sk(ssk)->copied_seq += incr;



out:

	if (!before(tcp_sk(ssk)->copied_seq, TCP_SKB_CB(skb)->end_seq))

		sk_eat_skb(ssk, skb);

	if (mptcp_subflow_get_map_offset(subflow) >= subflow->map_data_len)