Commit 017512a0 authored by Paolo Abeni's avatar Paolo Abeni Committed by David S. Miller
Browse files

mptcp: more DATA FIN fixes 



Currently data fin on data packet are not handled properly:
the 'rcv_data_fin_seq' field is interpreted as the last
sequence number carrying a valid data, but for data fin
packet with valid maps we currently store map_seq + map_len,
that is, the next value.

The 'write_seq' fields carries instead the value subseguent
to the last valid byte, so in mptcp_write_data_fin() we
never detect correctly the last DSS map.

Fixes: 7279da61 ("mptcp: Use MPTCP-level flag for sending DATA_FIN")
Fixes: 1a49b2c2 ("mptcp: Handle incoming 32-bit DATA_FIN values")
Reviewed-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c88c5ed7

net/mptcp/options.c

+5 −5
Original line number Diff line number Diff line
@@ -451,7 +451,10 @@ static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb, 
static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow,

				 struct sk_buff *skb, struct mptcp_ext *ext)

{

	u64 data_fin_tx_seq = READ_ONCE(mptcp_sk(subflow->conn)->write_seq);

	/* The write_seq value has already been incremented, so the actual

	 * sequence number for the DATA_FIN is one less.

	 */

	u64 data_fin_tx_seq = READ_ONCE(mptcp_sk(subflow->conn)->write_seq) - 1;



	if (!ext->use_map || !skb->len) {

		/* RFC6824 requires a DSS mapping with specific values
@@ -460,10 +463,7 @@ static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow, 
		ext->data_fin = 1;

		ext->use_map = 1;

		ext->dsn64 = 1;

		/* The write_seq value has already been incremented, so

		 * the actual sequence number for the DATA_FIN is one less.

		 */

		ext->data_seq = data_fin_tx_seq - 1;

		ext->data_seq = data_fin_tx_seq;

		ext->subflow_seq = 0;

		ext->data_len = 1;

	} else if (ext->data_seq + ext->data_len == data_fin_tx_seq) {

net/mptcp/subflow.c

+1 −1
Original line number Diff line number Diff line
@@ -749,7 +749,7 @@ static enum mapping_status get_mapping_status(struct sock *ssk, 
				return MAPPING_DATA_FIN;

			}

		} else {

			u64 data_fin_seq = mpext->data_seq + data_len;

			u64 data_fin_seq = mpext->data_seq + data_len - 1;



			/* If mpext->data_seq is a 32-bit value, data_fin_seq

			 * must also be limited to 32 bits.

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