Commit 9f39d365 authored by Oliver Hartkopp's avatar Oliver Hartkopp Committed by Marc Kleine-Budde
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can: isotp: add support for transmission without flow control 

Usually the ISO 15765-2 protocol is a point-to-point protocol to transfer
segmented PDUs to a dedicated receiver. This receiver sends a flow control
message to specify protocol options and timings (e.g. block size / STmin).

The so called functional addressing communication allows a 1:N
communication but is limited to a single frame length.

This new CAN_ISOTP_CF_BROADCAST allows an unconfirmed 1:N communication
with PDU length that would not fit into a single frame. This feature is
not covered by the ISO 15765-2 standard.

Link: https://lore.kernel.org/all/20220507115558.19065-1-socketcan@hartkopp.net


Signed-off-by: default avatarOliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 51a0d5e5

include/uapi/linux/can/isotp.h

+13 −12
Original line number Diff line number Diff line
@@ -124,18 +124,19 @@ struct can_isotp_ll_options { 


/* flags for isotp behaviour */



#define CAN_ISOTP_LISTEN_MODE	0x001	/* listen only (do not send FC) */

#define CAN_ISOTP_EXTEND_ADDR	0x002	/* enable extended addressing */

#define CAN_ISOTP_TX_PADDING	0x004	/* enable CAN frame padding tx path */

#define CAN_ISOTP_RX_PADDING	0x008	/* enable CAN frame padding rx path */

#define CAN_ISOTP_CHK_PAD_LEN	0x010	/* check received CAN frame padding */

#define CAN_ISOTP_CHK_PAD_DATA	0x020	/* check received CAN frame padding */

#define CAN_ISOTP_HALF_DUPLEX	0x040	/* half duplex error state handling */

#define CAN_ISOTP_FORCE_TXSTMIN	0x080	/* ignore stmin from received FC */

#define CAN_ISOTP_FORCE_RXSTMIN	0x100	/* ignore CFs depending on rx stmin */

#define CAN_ISOTP_RX_EXT_ADDR	0x200	/* different rx extended addressing */

#define CAN_ISOTP_WAIT_TX_DONE	0x400	/* wait for tx completion */

#define CAN_ISOTP_SF_BROADCAST	0x800	/* 1-to-N functional addressing */

#define CAN_ISOTP_LISTEN_MODE	0x0001	/* listen only (do not send FC) */

#define CAN_ISOTP_EXTEND_ADDR	0x0002	/* enable extended addressing */

#define CAN_ISOTP_TX_PADDING	0x0004	/* enable CAN frame padding tx path */

#define CAN_ISOTP_RX_PADDING	0x0008	/* enable CAN frame padding rx path */

#define CAN_ISOTP_CHK_PAD_LEN	0x0010	/* check received CAN frame padding */

#define CAN_ISOTP_CHK_PAD_DATA	0x0020	/* check received CAN frame padding */

#define CAN_ISOTP_HALF_DUPLEX	0x0040	/* half duplex error state handling */

#define CAN_ISOTP_FORCE_TXSTMIN	0x0080	/* ignore stmin from received FC */

#define CAN_ISOTP_FORCE_RXSTMIN	0x0100	/* ignore CFs depending on rx stmin */

#define CAN_ISOTP_RX_EXT_ADDR	0x0200	/* different rx extended addressing */

#define CAN_ISOTP_WAIT_TX_DONE	0x0400	/* wait for tx completion */

#define CAN_ISOTP_SF_BROADCAST	0x0800	/* 1-to-N functional addressing */

#define CAN_ISOTP_CF_BROADCAST	0x1000	/* 1-to-N transmission w/o FC */



/* protocol machine default values */

net/can/isotp.c

+79 −21
Original line number Diff line number Diff line
@@ -104,6 +104,7 @@ MODULE_ALIAS("can-proto-6"); 
#define FC_CONTENT_SZ 3	/* flow control content size in byte (FS/BS/STmin) */



#define ISOTP_CHECK_PADDING (CAN_ISOTP_CHK_PAD_LEN | CAN_ISOTP_CHK_PAD_DATA)

#define ISOTP_ALL_BC_FLAGS (CAN_ISOTP_SF_BROADCAST | CAN_ISOTP_CF_BROADCAST)



/* Flow Status given in FC frame */

#define ISOTP_FC_CTS 0		/* clear to send */
@@ -159,6 +160,23 @@ static inline struct isotp_sock *isotp_sk(const struct sock *sk) 
	return (struct isotp_sock *)sk;

}



static u32 isotp_bc_flags(struct isotp_sock *so)

{

	return so->opt.flags & ISOTP_ALL_BC_FLAGS;

}



static bool isotp_register_rxid(struct isotp_sock *so)

{

	/* no broadcast modes => register rx_id for FC frame reception */

	return (isotp_bc_flags(so) == 0);

}



static bool isotp_register_txecho(struct isotp_sock *so)

{

	/* all modes but SF_BROADCAST register for tx echo skbs */

	return (isotp_bc_flags(so) != CAN_ISOTP_SF_BROADCAST);

}



static enum hrtimer_restart isotp_rx_timer_handler(struct hrtimer *hrtimer)

{

	struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
@@ -803,7 +821,6 @@ static void isotp_create_fframe(struct canfd_frame *cf, struct isotp_sock *so, 
		cf->data[i] = so->tx.buf[so->tx.idx++];



	so->tx.sn = 1;

	so->tx.state = ISOTP_WAIT_FIRST_FC;

}



static void isotp_rcv_echo(struct sk_buff *skb, void *data)
@@ -936,7 +953,7 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) 
	off = (so->tx.ll_dl > CAN_MAX_DLEN) ? 1 : 0;



	/* does the given data fit into a single frame for SF_BROADCAST? */

	if ((so->opt.flags & CAN_ISOTP_SF_BROADCAST) &&

	if ((isotp_bc_flags(so) == CAN_ISOTP_SF_BROADCAST) &&

	    (size > so->tx.ll_dl - SF_PCI_SZ4 - ae - off)) {

		err = -EINVAL;

		goto err_out_drop;
@@ -1000,12 +1017,41 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) 
		/* don't enable wait queue for a single frame transmission */

		wait_tx_done = 0;

	} else {

		/* send first frame and wait for FC */

		/* send first frame */



		isotp_create_fframe(cf, so, ae);



		if (isotp_bc_flags(so) == CAN_ISOTP_CF_BROADCAST) {

			/* set timer for FC-less operation (STmin = 0) */

			if (so->opt.flags & CAN_ISOTP_FORCE_TXSTMIN)

				so->tx_gap = ktime_set(0, so->force_tx_stmin);

			else

				so->tx_gap = ktime_set(0, so->frame_txtime);



			/* disable wait for FCs due to activated block size */

			so->txfc.bs = 0;



			/* cfecho should have been zero'ed by init */

			if (so->cfecho)

				pr_notice_once("can-isotp: no fc cfecho %08X\n",

					       so->cfecho);



			/* set consecutive frame echo tag */

			so->cfecho = *(u32 *)cf->data;



			/* switch directly to ISOTP_SENDING state */

			so->tx.state = ISOTP_SENDING;



			/* start timeout for unlikely lost echo skb */

			hrtimer_sec = 2;

		} else {

			/* standard flow control check */

			so->tx.state = ISOTP_WAIT_FIRST_FC;



			/* start timeout for FC */

			hrtimer_sec = 1;

		}



		hrtimer_start(&so->txtimer, ktime_set(hrtimer_sec, 0),

			      HRTIMER_MODE_REL_SOFT);

	}
@@ -1025,6 +1071,9 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) 
		if (hrtimer_sec)

			hrtimer_cancel(&so->txtimer);



		/* reset consecutive frame echo tag */

		so->cfecho = 0;



		goto err_out_drop;

	}
@@ -1120,15 +1169,17 @@ static int isotp_release(struct socket *sock) 
	lock_sock(sk);



	/* remove current filters & unregister */

	if (so->bound && (!(so->opt.flags & CAN_ISOTP_SF_BROADCAST))) {

	if (so->bound && isotp_register_txecho(so)) {

		if (so->ifindex) {

			struct net_device *dev;



			dev = dev_get_by_index(net, so->ifindex);

			if (dev) {

				if (isotp_register_rxid(so))

					can_rx_unregister(net, dev, so->rxid,

							  SINGLE_MASK(so->rxid),

							  isotp_rcv, sk);



				can_rx_unregister(net, dev, so->txid,

						  SINGLE_MASK(so->txid),

						  isotp_rcv_echo, sk);
@@ -1164,7 +1215,6 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len) 
	canid_t tx_id, rx_id;

	int err = 0;

	int notify_enetdown = 0;

	int do_rx_reg = 1;



	if (len < ISOTP_MIN_NAMELEN)

		return -EINVAL;
@@ -1192,12 +1242,8 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len) 
		goto out;

	}



	/* do not register frame reception for functional addressing */

	if (so->opt.flags & CAN_ISOTP_SF_BROADCAST)

		do_rx_reg = 0;



	/* do not validate rx address for functional addressing */

	if (do_rx_reg && rx_id == tx_id) {

	/* ensure different CAN IDs when the rx_id is to be registered */

	if (isotp_register_rxid(so) && rx_id == tx_id) {

		err = -EADDRNOTAVAIL;

		goto out;

	}
@@ -1222,10 +1268,11 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len) 


	ifindex = dev->ifindex;



	if (do_rx_reg) {

	if (isotp_register_rxid(so))

		can_rx_register(net, dev, rx_id, SINGLE_MASK(rx_id),

				isotp_rcv, sk, "isotp", sk);



	if (isotp_register_txecho(so)) {

		/* no consecutive frame echo skb in flight */

		so->cfecho = 0;
@@ -1294,6 +1341,15 @@ static int isotp_setsockopt_locked(struct socket *sock, int level, int optname, 
		if (!(so->opt.flags & CAN_ISOTP_RX_EXT_ADDR))

			so->opt.rx_ext_address = so->opt.ext_address;



		/* these broadcast flags are not allowed together */

		if (isotp_bc_flags(so) == ISOTP_ALL_BC_FLAGS) {

			/* CAN_ISOTP_SF_BROADCAST is prioritized */

			so->opt.flags &= ~CAN_ISOTP_CF_BROADCAST;



			/* give user feedback on wrong config attempt */

			ret = -EINVAL;

		}



		/* check for frame_txtime changes (0 => no changes) */

		if (so->opt.frame_txtime) {

			if (so->opt.frame_txtime == CAN_ISOTP_FRAME_TXTIME_ZERO)
@@ -1444,10 +1500,12 @@ static void isotp_notify(struct isotp_sock *so, unsigned long msg, 
	case NETDEV_UNREGISTER:

		lock_sock(sk);

		/* remove current filters & unregister */

		if (so->bound && (!(so->opt.flags & CAN_ISOTP_SF_BROADCAST))) {

		if (so->bound && isotp_register_txecho(so)) {

			if (isotp_register_rxid(so))

				can_rx_unregister(dev_net(dev), dev, so->rxid,

						  SINGLE_MASK(so->rxid),

						  isotp_rcv, sk);



			can_rx_unregister(dev_net(dev), dev, so->txid,

					  SINGLE_MASK(so->txid),

					  isotp_rcv_echo, sk);