From 9f39d36530e5678d092d53c5c2c60d82b4dcc169 Mon Sep 17 00:00:00 2001 From: Oliver Hartkopp Date: Sat, 7 May 2022 13:55:58 +0200 Subject: 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: Oliver Hartkopp Signed-off-by: Marc Kleine-Budde --- net/can/isotp.c | 100 ++++++++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 79 insertions(+), 21 deletions(-) (limited to 'net/can/isotp.c') 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); -- cgit v1.2.3-59-g8ed1b