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Date: Mon, 16 May 2022 22:26:19 +0200
From: Marc Kleine-Budde <mkl@...gutronix.de>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net, kuba@...nel.org, linux-can@...r.kernel.org,
kernel@...gutronix.de, Oliver Hartkopp <socketcan@...tkopp.net>,
Marc Kleine-Budde <mkl@...gutronix.de>
Subject: [PATCH net-next 3/9] can: isotp: add support for transmission without flow control
From: Oliver Hartkopp <socketcan@...tkopp.net>
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: Oliver Hartkopp <socketcan@...tkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
---
include/uapi/linux/can/isotp.h | 25 +++++----
net/can/isotp.c | 100 ++++++++++++++++++++++++++-------
2 files changed, 92 insertions(+), 33 deletions(-)
diff --git a/include/uapi/linux/can/isotp.h b/include/uapi/linux/can/isotp.h
index 590f8aea2b6d..439c982f7e81 100644
--- a/include/uapi/linux/can/isotp.h
+++ b/include/uapi/linux/can/isotp.h
@@ -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 */
diff --git a/net/can/isotp.c b/net/can/isotp.c
index 35a1ae61744c..2caeeae8ec16 100644
--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -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);
- /* start timeout for FC */
- hrtimer_sec = 1;
+ 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) {
- can_rx_unregister(net, dev, so->rxid,
- SINGLE_MASK(so->rxid),
- isotp_rcv, sk);
+ 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))) {
- can_rx_unregister(dev_net(dev), dev, so->rxid,
- SINGLE_MASK(so->rxid),
- isotp_rcv, sk);
+ 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);
--
2.35.1
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