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. Signed-off-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx> Signed-off-by: Thomas Wagner <thwa1@xxxxxx> Link: https://lore.kernel.org/r/20201203140604.25488-3-socketcan@xxxxxxxxxxxx Link: https://lore.kernel.org/r/20201204135557.55599-1-thwa1@xxxxxx --- include/uapi/linux/can/isotp.h | 2 +- net/can/isotp.c | 42 +++++++++++++++++++++++----------- 2 files changed, 30 insertions(+), 14 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..7839c3b9e5be 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) { @@ -1050,19 +1055,29 @@ 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) - return -EADDRNOTAVAIL; + /* 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) { + if (addr->can_addr.tp.rx_id == addr->can_addr.tp.tx_id) + return -EADDRNOTAVAIL; + + if (addr->can_addr.tp.rx_id & (CAN_ERR_FLAG | CAN_RTR_FLAG)) + return -EADDRNOTAVAIL; + } - if ((addr->can_addr.tp.rx_id | addr->can_addr.tp.tx_id) & - (CAN_ERR_FLAG | CAN_RTR_FLAG)) + if (addr->can_addr.tp.tx_id & (CAN_ERR_FLAG | CAN_RTR_FLAG)) return -EADDRNOTAVAIL; if (!addr->can_ifindex) return -ENODEV; @@ -1091,17 +1106,18 @@ 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 +1316,11 @@ 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
