From: Oliver Hartkopp <socketcan@xxxxxxxxxxxx> 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 <thwa1@xxxxxx> Signed-off-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx> Tested-by: Thomas Wagner <thwa1@xxxxxx> Link: https://lore.kernel.org/r/20201203140604.25488-3-socketcan@xxxxxxxxxxxx Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> --- 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 @@ -135,7 +135,7 @@ struct can_isotp_ll_options { #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 */ 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 @@ -865,6 +865,14 @@ 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; @@ -891,9 +899,6 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) 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. @@ -1016,7 +1021,7 @@ static int isotp_release(struct socket *sock) 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; @@ -1052,6 +1057,7 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len) 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; @@ -1066,6 +1072,10 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len) 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 && @@ -1093,13 +1103,14 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len) 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); @@ -1302,7 +1313,7 @@ static int isotp_notifier(struct notifier_block *nb, unsigned long 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); -- 2.29.2
