When CAN_ISOTP_SF_BROADCAST is set in the CAN_ISOTP_OPTS flags the
CAN_ISOTP socket is switched into functional addressing mode, where
only single frame (SF) protocol data units can be send on the specified
CAN interface and the given tp.tx_id after bind().
In opposite to normal and extended addressing this socket does not
register a CAN-ID for reception which would be needed for a 1-to-1
ISOTP connection with a segmented bi-directional data transfer.
Sending SFs on this socket is therefore a TX-only 'broadcast' operation.
Suggested-by: Thomas Wagner <th...@web.de>
Tested-by: Thomas Wagner <th...@web.de>
Signed-off-by: Oliver Hartkopp <socket...@hartkopp.net>
---
include/uapi/linux/can/isotp.h | 2 +-
net/can/isotp.c | 29 ++++++++++++++++++++---------
2 files changed, 21 insertions(+), 10 deletions(-)
diff --git a/include/uapi/linux/can/isotp.h b/include/uapi/linux/can/isotp.h
index 7793b26aa154..c55935b64ccc 100644
--- a/include/uapi/linux/can/isotp.h
+++ b/include/uapi/linux/can/isotp.h
@@ -133,11 +133,11 @@ struct can_isotp_ll_options {
#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 */
/* default values */
#define CAN_ISOTP_DEFAULT_FLAGS 0
#define CAN_ISOTP_DEFAULT_EXT_ADDRESS 0x00
diff --git a/net/can/isotp.c b/net/can/isotp.c
index 26bdc3c20b7e..5ce26e568f16 100644
--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -863,10 +863,18 @@ static int isotp_sendmsg(struct socket *sock, struct
msghdr *msg, size_t size)
}
if (!size || size > MAX_MSG_LENGTH)
return -EINVAL;
+ /* take care of a potential SF_DL ESC offset for TX_DL > 8 */
+ 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) &&
+ (size > so->tx.ll_dl - SF_PCI_SZ4 - ae - off))
+ return -EINVAL;
+
err = memcpy_from_msg(so->tx.buf, msg, size);
if (err < 0)
return err;
dev = dev_get_by_index(sock_net(sk), so->ifindex);
@@ -889,13 +897,10 @@ static int isotp_sendmsg(struct socket *sock, struct
msghdr *msg, size_t size)
so->tx.idx = 0;
cf = (struct canfd_frame *)skb->data;
skb_put(skb, so->ll.mtu);
- /* take care of a potential SF_DL ESC offset for TX_DL > 8 */
- off = (so->tx.ll_dl > CAN_MAX_DLEN) ? 1 : 0;
-
/* check for single frame transmission depending on TX_DL */
if (size <= so->tx.ll_dl - SF_PCI_SZ4 - ae - off) {
/* The message size generally fits into a SingleFrame - good.
*
* SF_DL ESC offset optimization:
@@ -1014,11 +1019,11 @@ static int isotp_release(struct socket *sock)
hrtimer_cancel(&so->txtimer);
hrtimer_cancel(&so->rxtimer);
/* remove current filters & unregister */
- if (so->bound) {
+ if (so->bound && (!(so->opt.flags & CAN_ISOTP_SF_BROADCAST))) {
if (so->ifindex) {
struct net_device *dev;
dev = dev_get_by_index(net, so->ifindex);
if (dev) {
@@ -1050,10 +1055,11 @@ static int isotp_bind(struct socket *sock, struct
sockaddr *uaddr, int len)
struct net *net = sock_net(sk);
int ifindex;
struct net_device *dev;
int err = 0;
int notify_enetdown = 0;
+ int do_rx_reg = 1;
if (len < CAN_REQUIRED_SIZE(struct sockaddr_can, can_addr.tp))
return -EINVAL;
if (addr->can_addr.tp.rx_id == addr->can_addr.tp.tx_id)
@@ -1064,10 +1070,14 @@ static int isotp_bind(struct socket *sock, struct
sockaddr *uaddr, int len)
return -EADDRNOTAVAIL;
if (!addr->can_ifindex)
return -ENODEV;
+ /* do not register frame reception for functional addressing */
+ if (so->opt.flags & CAN_ISOTP_SF_BROADCAST)
+ do_rx_reg = 0;
+
lock_sock(sk);
if (so->bound && addr->can_ifindex == so->ifindex &&
addr->can_addr.tp.rx_id == so->rxid &&
addr->can_addr.tp.tx_id == so->txid)
@@ -1091,17 +1101,18 @@ static int isotp_bind(struct socket *sock, struct
sockaddr *uaddr, int len)
if (!(dev->flags & IFF_UP))
notify_enetdown = 1;
ifindex = dev->ifindex;
- can_rx_register(net, dev, addr->can_addr.tp.rx_id,
- SINGLE_MASK(addr->can_addr.tp.rx_id), isotp_rcv, sk,
- "isotp", sk);
+ if (do_rx_reg)
+ can_rx_register(net, dev, addr->can_addr.tp.rx_id,
+ SINGLE_MASK(addr->can_addr.tp.rx_id),
+ isotp_rcv, sk, "isotp", sk);
dev_put(dev);
- if (so->bound) {
+ if (so->bound && do_rx_reg) {
/* unregister old filter */
if (so->ifindex) {
dev = dev_get_by_index(net, so->ifindex);
if (dev) {
can_rx_unregister(net, dev, so->rxid,
@@ -1300,11 +1311,11 @@ static int isotp_notifier(struct notifier_block *nb,
unsigned long msg,
switch (msg) {
case NETDEV_UNREGISTER:
lock_sock(sk);
/* remove current filters & unregister */
- if (so->bound)
+ 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);
so->ifindex = 0;
--
2.29.2
