Subject: Re: [PATCH v1 2/2] net: j1939: extend UAPI to notify about RX status

From: David Jander <[email-masked]>
Date: Tue, 6 Jul 2021 15:28:34 +0200

On Tue,  6 Jul 2021 13:57:58 +0200
Oleksij Rempel <[email-masked]> wrote:

> To be able to create applications with user friendly feedback, we need be
> able to provide receive status information.
> 
> Typical ETP transfer may take seconds or even hours. To give user some
> clue or show a progress bar, the stack should push status updates.
> Same as for the TX information, the socket error queue will be used with
> following new signals:
> - J1939_EE_INFO_RX_RTS   - received and accepted request to send signal.
> - J1939_EE_INFO_RX_DPO   - received data package offset signal
> - J1939_EE_INFO_RX_ABORT - RX session was aborted
> 
> Instead of completion signal, user will get data package.
> To activate this signals, application should set
> SOF_TIMESTAMPING_RX_SOFTWARE to the SO_TIMESTAMPING socket option. This
> will avoid unpredictable application behavior for the old software.
> 
> Signed-off-by: Oleksij Rempel <[email-masked]>
> ---
>  include/uapi/linux/can/j1939.h |   9 +++
>  net/can/j1939/j1939-priv.h     |   4 +
>  net/can/j1939/socket.c         | 135 +++++++++++++++++++++++++--------
>  net/can/j1939/transport.c      |  22 +++++-
>  4 files changed, 136 insertions(+), 34 deletions(-)
> 
> diff --git a/include/uapi/linux/can/j1939.h b/include/uapi/linux/can/j1939.h
> index df6e821075c1..dc2a8e15c0b7 100644
> --- a/include/uapi/linux/can/j1939.h
> +++ b/include/uapi/linux/can/j1939.h
> @@ -78,11 +78,20 @@ enum {
>  enum {
>  	J1939_NLA_PAD,
>  	J1939_NLA_BYTES_ACKED,
> +	J1939_NLA_TOTAL_SIZE,
> +	J1939_NLA_DEST_ADDR,
> +	J1939_NLA_DEST_NAME,
> +	J1939_NLA_SRC_ADDR,
> +	J1939_NLA_SRC_NAME,
> +	J1939_NLA_PGN,
>  };
>  
>  enum {
>  	J1939_EE_INFO_NONE,
>  	J1939_EE_INFO_TX_ABORT,
> +	J1939_EE_INFO_RX_RTS,
> +	J1939_EE_INFO_RX_DPO,
> +	J1939_EE_INFO_RX_ABORT,
>  };
>  
>  struct j1939_filter {
> diff --git a/net/can/j1939/j1939-priv.h b/net/can/j1939/j1939-priv.h
> index 93b8ad7f7d04..f6df20808f5e 100644
> --- a/net/can/j1939/j1939-priv.h
> +++ b/net/can/j1939/j1939-priv.h
> @@ -23,6 +23,9 @@ enum j1939_sk_errqueue_type {
>  	J1939_ERRQUEUE_TX_ACK,
>  	J1939_ERRQUEUE_TX_SCHED,
>  	J1939_ERRQUEUE_TX_ABORT,
> +	J1939_ERRQUEUE_RX_RTS,
> +	J1939_ERRQUEUE_RX_DPO,
> +	J1939_ERRQUEUE_RX_ABORT,
>  };
>  
>  /* j1939 devices */
> @@ -87,6 +90,7 @@ struct j1939_priv {
>  	struct list_head j1939_socks;
>  
>  	struct kref rx_kref;
> +	u32 rx_tskey;
>  };
>  
>  void j1939_ecu_put(struct j1939_ecu *ecu);
> diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c
> index c2bf1c02597e..30b99897c473 100644
> --- a/net/can/j1939/socket.c
> +++ b/net/can/j1939/socket.c
> @@ -902,20 +902,33 @@ static struct sk_buff *j1939_sk_alloc_skb(struct net_device *ndev,
>  	return NULL;
>  }
>  
> -static size_t j1939_sk_opt_stats_get_size(void)
> +static size_t j1939_sk_opt_stats_get_size(enum j1939_sk_errqueue_type type)
>  {
> -	return
> -		nla_total_size(sizeof(u32)) + /* J1939_NLA_BYTES_ACKED */
> -		0;
> +	switch (type) {
> +	case J1939_ERRQUEUE_RX_RTS:
> +		return
> +			nla_total_size(sizeof(u32)) + /* J1939_NLA_BYTES_ALL */
> +			nla_total_size(sizeof(u64)) + /* J1939_NLA_DEST_ADDR */
> +			nla_total_size(sizeof(u64)) + /* J1939_NLA_SRC_ADDR */

DST and SRC address are u8...?

> +			nla_total_size(sizeof(u64)) + /* J1939_NLA_DEST_NAME */
> +			nla_total_size(sizeof(u64)) + /* J1939_NLA_SRC_NAME */
> +			nla_total_size(sizeof(u32)) + /* J1939_NLA_PGN */
> +			0;
> +	default:
> +		return
> +			nla_total_size(sizeof(u32)) + /* J1939_NLA_BYTES_ACKED */
> +			0;
> +	}
>  }
>  
>  static struct sk_buff *
> -j1939_sk_get_timestamping_opt_stats(struct j1939_session *session)
> +j1939_sk_get_timestamping_opt_stats(struct j1939_session *session,
> +				    enum j1939_sk_errqueue_type type)
>  {
>  	struct sk_buff *stats;
>  	u32 size;
>  
> -	stats = alloc_skb(j1939_sk_opt_stats_get_size(), GFP_ATOMIC);
> +	stats = alloc_skb(j1939_sk_opt_stats_get_size(type), GFP_ATOMIC);
>  	if (!stats)
>  		return NULL;
>  
> @@ -925,32 +938,67 @@ j1939_sk_get_timestamping_opt_stats(struct j1939_session *session)
>  		size = min(session->pkt.tx_acked * 7,
>  			   session->total_message_size);
>  
> -	nla_put_u32(stats, J1939_NLA_BYTES_ACKED, size);
> +	switch (type) {
> +	case J1939_ERRQUEUE_RX_RTS:
> +		nla_put_u32(stats, J1939_NLA_TOTAL_SIZE,
> +			    session->total_message_size);
> +		nla_put_u32(stats, J1939_NLA_PGN,
> +			    session->skcb.addr.pgn);
> +		nla_put_u64_64bit(stats, J1939_NLA_SRC_NAME,
> +				  session->skcb.addr.src_name, J1939_NLA_PAD);
> +		nla_put_u64_64bit(stats, J1939_NLA_DEST_NAME,
> +				  session->skcb.addr.dst_name, J1939_NLA_PAD);
> +		nla_put_u8(stats, J1939_NLA_SRC_ADDR,
> +			   session->skcb.addr.sa);
> +		nla_put_u8(stats, J1939_NLA_DEST_ADDR,
> +			   session->skcb.addr.da);

See above.
Also, shouldn't the order of these be the same as in
j1939_sk_opt_stats_get_size()... for readability?

> +		break;
> +	default:
> +		nla_put_u32(stats, J1939_NLA_BYTES_ACKED, size);
> +	}
>  
>  	return stats;
>  }
>  
> -void j1939_sk_errqueue(struct j1939_session *session,
> -		       enum j1939_sk_errqueue_type type)
> +static void __j1939_sk_errqueue(struct j1939_session *session, struct sock *sk,
> +				enum j1939_sk_errqueue_type type)
>  {
>  	struct j1939_priv *priv = session->priv;
> -	struct sock *sk = session->sk;
>  	struct j1939_sock *jsk;
>  	struct sock_exterr_skb *serr;
>  	struct sk_buff *skb;
>  	char *state = "UNK";
>  	int err;
>  
> -	/* currently we have no sk for the RX session */
> -	if (!sk)
> -		return;
> -
>  	jsk = j1939_sk(sk);
>  
>  	if (!(jsk->state & J1939_SOCK_ERRQUEUE))
>  		return;
>  
> -	skb = j1939_sk_get_timestamping_opt_stats(session);
> +	switch (type) {
> +	case J1939_ERRQUEUE_TX_ACK:
> +		if (!(sk->sk_tsflags & SOF_TIMESTAMPING_TX_ACK))
> +			return;
> +		break;
> +	case J1939_ERRQUEUE_TX_SCHED:
> +		if (!(sk->sk_tsflags & SOF_TIMESTAMPING_TX_SCHED))
> +			return;
> +		break;
> +	case J1939_ERRQUEUE_TX_ABORT:
> +		break;
> +	case J1939_ERRQUEUE_RX_RTS:
> +		fallthrough;
> +	case J1939_ERRQUEUE_RX_DPO:
> +		fallthrough;
> +	case J1939_ERRQUEUE_RX_ABORT:
> +		if (!(sk->sk_tsflags & SOF_TIMESTAMPING_RX_SOFTWARE))
> +			return;
> +		break;
> +	default:
> +		netdev_err(priv->ndev, "Unknown errqueue type %i\n", type);
> +	}
> +
> +	skb = j1939_sk_get_timestamping_opt_stats(session, type);
>  	if (!skb)
>  		return;
>  
> @@ -962,35 +1010,41 @@ void j1939_sk_errqueue(struct j1939_session *session,
>  	memset(serr, 0, sizeof(*serr));
>  	switch (type) {
>  	case J1939_ERRQUEUE_TX_ACK:
> -		if (!(sk->sk_tsflags & SOF_TIMESTAMPING_TX_ACK)) {
> -			kfree_skb(skb);
> -			return;
> -		}
> -
>  		serr->ee.ee_errno = ENOMSG;
>  		serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING;
>  		serr->ee.ee_info = SCM_TSTAMP_ACK;
> -		state = "ACK";
> +		state = "TX ACK";
>  		break;
>  	case J1939_ERRQUEUE_TX_SCHED:
> -		if (!(sk->sk_tsflags & SOF_TIMESTAMPING_TX_SCHED)) {
> -			kfree_skb(skb);
> -			return;
> -		}
> -
>  		serr->ee.ee_errno = ENOMSG;
>  		serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING;
>  		serr->ee.ee_info = SCM_TSTAMP_SCHED;
> -		state = "SCH";
> +		state = "TX SCH";
>  		break;
>  	case J1939_ERRQUEUE_TX_ABORT:
>  		serr->ee.ee_errno = session->err;
>  		serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
>  		serr->ee.ee_info = J1939_EE_INFO_TX_ABORT;
> -		state = "ABT";
> +		state = "TX ABT";
> +		break;
> +	case J1939_ERRQUEUE_RX_RTS:
> +		serr->ee.ee_errno = ENOMSG;
> +		serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
> +		serr->ee.ee_info = J1939_EE_INFO_RX_RTS;
> +		state = "RX RTS";
> +		break;
> +	case J1939_ERRQUEUE_RX_DPO:
> +		serr->ee.ee_errno = ENOMSG;
> +		serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
> +		serr->ee.ee_info = J1939_EE_INFO_RX_DPO;
> +		state = "RX DPO";
> +		break;
> +	case J1939_ERRQUEUE_RX_ABORT:
> +		serr->ee.ee_errno = session->err;
> +		serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
> +		serr->ee.ee_info = J1939_EE_INFO_RX_ABORT;
> +		state = "RX ABT";
>  		break;
> -	default:
> -		netdev_err(priv->ndev, "Unknown errqueue type %i\n", type);
>  	}
>  
>  	serr->opt_stats = true;
> @@ -1005,6 +1059,27 @@ void j1939_sk_errqueue(struct j1939_session *session,
>  		kfree_skb(skb);
>  };
>  
> +void j1939_sk_errqueue(struct j1939_session *session,
> +		       enum j1939_sk_errqueue_type type)
> +{
> +	struct j1939_priv *priv = session->priv;
> +	struct j1939_sock *jsk;
> +
> +	if (session->sk) {
> +		/* send TX notifications to the socket of origin  */
> +		__j1939_sk_errqueue(session, session->sk, type);
> +		return;
> +	}
> +
> +	/* spread RX notifications to all sockets subscribed to this session */
> +	spin_lock_bh(&priv->j1939_socks_lock);
> +	list_for_each_entry(jsk, &priv->j1939_socks, list) {
> +		if (j1939_sk_recv_match_one(jsk, &session->skcb))
> +			__j1939_sk_errqueue(session, &jsk->sk, type);
> +	}
> +	spin_unlock_bh(&priv->j1939_socks_lock);
> +};
> +
>  void j1939_sk_send_loop_abort(struct sock *sk, int err)
>  {
>  	sk->sk_err = err;
> diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c
> index 362cf38cacca..cb358646e382 100644
> --- a/net/can/j1939/transport.c
> +++ b/net/can/j1939/transport.c
> @@ -260,10 +260,14 @@ static void __j1939_session_drop(struct j1939_session *session)
>  
>  static void j1939_session_destroy(struct j1939_session *session)
>  {
> -	if (session->err)
> -		j1939_sk_errqueue(session, J1939_ERRQUEUE_TX_ABORT);
> -	else
> -		j1939_sk_errqueue(session, J1939_ERRQUEUE_TX_ACK);
> +	if (session->transmission) {
> +		if (session->err)
> +			j1939_sk_errqueue(session, J1939_ERRQUEUE_TX_ABORT);
> +		else
> +			j1939_sk_errqueue(session, J1939_ERRQUEUE_TX_ACK);
> +	} else if (session->err) {
> +			j1939_sk_errqueue(session, J1939_ERRQUEUE_RX_ABORT);
> +	}
>  
>  	netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);
>  
> @@ -1087,6 +1091,8 @@ static void __j1939_session_cancel(struct j1939_session *session,
>  
>  	if (session->sk)
>  		j1939_sk_send_loop_abort(session->sk, session->err);
> +	else
> +		j1939_sk_errqueue(session, J1939_ERRQUEUE_RX_ABORT);
>  }
>  
>  static void j1939_session_cancel(struct j1939_session *session,
> @@ -1297,6 +1303,8 @@ static void j1939_xtp_rx_abort_one(struct j1939_priv *priv, struct sk_buff *skb,
>  	session->err = j1939_xtp_abort_to_errno(priv, abort);
>  	if (session->sk)
>  		j1939_sk_send_loop_abort(session->sk, session->err);
> +	else
> +		j1939_sk_errqueue(session, J1939_ERRQUEUE_RX_ABORT);
>  	j1939_session_deactivate_activate_next(session);
>  
>  abort_put:
> @@ -1597,6 +1605,9 @@ j1939_session *j1939_xtp_rx_rts_session_new(struct j1939_priv *priv,
>  	session->pkt.rx = 0;
>  	session->pkt.tx = 0;
>  
> +	session->tskey = priv->rx_tskey++;
> +	j1939_sk_errqueue(session, J1939_ERRQUEUE_RX_RTS);
> +
>  	WARN_ON_ONCE(j1939_session_activate(session));
>  
>  	return session;
> @@ -1719,6 +1730,9 @@ static void j1939_xtp_rx_dpo_one(struct j1939_session *session,
>  	session->pkt.dpo = j1939_etp_ctl_to_packet(skb->data);
>  	session->last_cmd = dat[0];
>  	j1939_tp_set_rxtimeout(session, 750);
> +
> +	if (!session->transmission)
> +		j1939_sk_errqueue(session, J1939_ERRQUEUE_RX_DPO);
>  }
>  
>  static void j1939_xtp_rx_dpo(struct j1939_priv *priv, struct sk_buff *skb,

Best regards,

-- 
David Jander
Protonic Holland.