Commit 1a49b2c2 authored by Mat Martineau's avatar Mat Martineau Committed by David S. Miller
Browse files

mptcp: Handle incoming 32-bit DATA_FIN values 

The peer may send a DATA_FIN mapping with either a 32-bit or 64-bit
sequence number. When a 32-bit sequence number is received for the
DATA_FIN, it must be expanded to 64 bits before comparing it to the
last acked sequence number. This expansion was missing.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/93


Fixes: 3721b9b6 ("mptcp: Track received DATA_FIN sequence number and add related helpers")
Signed-off-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 917944da

net/mptcp/options.c

+4 −3
Original line number Diff line number Diff line
@@ -782,7 +782,7 @@ static void update_una(struct mptcp_sock *msk, 
	}

}



bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq)

bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit)

{

	/* Skip if DATA_FIN was already received.

	 * If updating simultaneously with the recvmsg loop, values
@@ -792,7 +792,8 @@ bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq) 
	if (READ_ONCE(msk->rcv_data_fin) || !READ_ONCE(msk->first))

		return false;



	WRITE_ONCE(msk->rcv_data_fin_seq, data_fin_seq);

	WRITE_ONCE(msk->rcv_data_fin_seq,

		   expand_ack(READ_ONCE(msk->ack_seq), data_fin_seq, use_64bit));

	WRITE_ONCE(msk->rcv_data_fin, 1);



	return true;
@@ -875,7 +876,7 @@ void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb, 
	 */

	if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) {

		if (mp_opt.data_fin && mp_opt.data_len == 1 &&

		    mptcp_update_rcv_data_fin(msk, mp_opt.data_seq) &&

		    mptcp_update_rcv_data_fin(msk, mp_opt.data_seq, mp_opt.dsn64) &&

		    schedule_work(&msk->work))

			sock_hold(subflow->conn);

net/mptcp/protocol.h

+1 −1
Original line number Diff line number Diff line
@@ -387,7 +387,7 @@ void mptcp_data_ready(struct sock *sk, struct sock *ssk); 
bool mptcp_finish_join(struct sock *sk);

void mptcp_data_acked(struct sock *sk);

void mptcp_subflow_eof(struct sock *sk);

bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq);

bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit);



void __init mptcp_token_init(void);

static inline void mptcp_token_init_request(struct request_sock *req)

net/mptcp/subflow.c

+13 −3
Original line number Diff line number Diff line
@@ -731,7 +731,8 @@ static enum mapping_status get_mapping_status(struct sock *ssk, 


	if (mpext->data_fin == 1) {

		if (data_len == 1) {

			bool updated = mptcp_update_rcv_data_fin(msk, mpext->data_seq);

			bool updated = mptcp_update_rcv_data_fin(msk, mpext->data_seq,

								 mpext->dsn64);

			pr_debug("DATA_FIN with no payload seq=%llu", mpext->data_seq);

			if (subflow->map_valid) {

				/* A DATA_FIN might arrive in a DSS
@@ -748,8 +749,17 @@ static enum mapping_status get_mapping_status(struct sock *ssk, 
				return MAPPING_DATA_FIN;

			}

		} else {

			mptcp_update_rcv_data_fin(msk, mpext->data_seq + data_len);

			pr_debug("DATA_FIN with mapping seq=%llu", mpext->data_seq + data_len);

			u64 data_fin_seq = mpext->data_seq + data_len;



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

			 * must also be limited to 32 bits.

			 */

			if (!mpext->dsn64)

				data_fin_seq &= GENMASK_ULL(31, 0);



			mptcp_update_rcv_data_fin(msk, data_fin_seq, mpext->dsn64);

			pr_debug("DATA_FIN with mapping seq=%llu dsn64=%d",

				 data_fin_seq, mpext->dsn64);

		}



		/* Adjust for DATA_FIN using 1 byte of sequence space */

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