With ISO 15765-2:2016 the PDU size is not limited to 2^12 - 1 (4095) bytes but can be represented as a 32 bit unsigned integer value which allows 2^32 - 1 bytes (~4GB). The use-cases like automotive unified diagnostic services (UDS) and flashing of ECUs still use the small static buffers which are provided at socket creation time. When a use-case requires to transfer PDUs up to 1025 kByte the maximum PDU size can now be extended by setting the module parameter max_pdu_size. The extended size buffers are only allocated on a per-socket/connection base when needed at run-time. Link: https://github.com/raspberrypi/linux/issues/5371 Signed-off-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx> --- net/can/isotp.c | 59 ++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 51 insertions(+), 8 deletions(-) diff --git a/net/can/isotp.c b/net/can/isotp.c index 9bc344851704..3f052deeaaa0 100644 --- a/net/can/isotp.c +++ b/net/can/isotp.c @@ -83,14 +83,22 @@ MODULE_ALIAS("can-proto-6"); (CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG) : \ (CAN_SFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG)) /* ISO 15765-2:2016 supports more than 4095 byte per ISO PDU as the FF_DL can * take full 32 bit values (4 Gbyte). We would need some good concept to handle - * this between user space and kernel space. For now increase the static buffer - * to something about 64 kbyte to be able to test this new functionality. + * this between user space and kernel space. For now set the static buffer to + * something about 8 kbyte to be able to test this new functionality. */ -#define MAX_MSG_LENGTH 66000 +#define DEFAULT_MAX_PDU_SIZE 8300 + +/* limit the isotp pdu size from the optional module parameter to 1MByte */ +#define MAX_PDU_SIZE (1025 * 1024U) + +static unsigned int max_pdu_size __read_mostly = DEFAULT_MAX_PDU_SIZE; +module_param(max_pdu_size, uint, 0444); +MODULE_PARM_DESC(max_pdu_size, "maximum isotp pdu size (default " + __stringify(DEFAULT_MAX_PDU_SIZE) ")"); /* N_PCI type values in bits 7-4 of N_PCI bytes */ #define N_PCI_SF 0x00 /* single frame */ #define N_PCI_FF 0x10 /* first frame */ #define N_PCI_CF 0x20 /* consecutive frame */ @@ -121,17 +129,19 @@ enum { ISOTP_WAIT_DATA, ISOTP_SENDING }; struct tpcon { - unsigned int idx; + u8 *buf; + unsigned int buflen; unsigned int len; + unsigned int idx; u32 state; u8 bs; u8 sn; u8 ll_dl; - u8 buf[MAX_MSG_LENGTH + 1]; + u8 sbuf[DEFAULT_MAX_PDU_SIZE]; }; struct isotp_sock { struct sock sk; int bound; @@ -501,11 +511,21 @@ static int isotp_rcv_ff(struct sock *sk, struct canfd_frame *cf, int ae) off = (so->rx.ll_dl > CAN_MAX_DLEN) ? 1 : 0; if (so->rx.len + ae + off + ff_pci_sz < so->rx.ll_dl) return 1; - if (so->rx.len > MAX_MSG_LENGTH) { + /* PDU size > default => try max_pdu_size */ + if (so->rx.len > so->rx.buflen && so->rx.buflen < max_pdu_size) { + u8 *newbuf = kmalloc(max_pdu_size, GFP_ATOMIC); + + if (newbuf) { + so->rx.buf = newbuf; + so->rx.buflen = max_pdu_size; + } + } + + if (so->rx.len > so->rx.buflen) { /* send FC frame with overflow status */ isotp_send_fc(sk, ae, ISOTP_FC_OVFLW); return 1; } @@ -945,11 +965,21 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) goto err_out; so->tx.state = ISOTP_SENDING; } - if (!size || size > MAX_MSG_LENGTH) { + /* PDU size > default => try max_pdu_size */ + if (size > so->tx.buflen && so->tx.buflen < max_pdu_size) { + u8 *newbuf = kmalloc(max_pdu_size, GFP_KERNEL); + + if (newbuf) { + so->tx.buf = newbuf; + so->tx.buflen = max_pdu_size; + } + } + + if (!size || size > so->tx.buflen) { err = -EINVAL; goto err_out_drop; } /* take care of a potential SF_DL ESC offset for TX_DL > 8 */ @@ -1193,10 +1223,16 @@ static int isotp_release(struct socket *sock) hrtimer_cancel(&so->rxtimer); so->ifindex = 0; so->bound = 0; + if (so->rx.buf != so->rx.sbuf) + kfree(so->rx.buf); + + if (so->tx.buf != so->tx.sbuf) + kfree(so->tx.buf); + sock_orphan(sk); sock->sk = NULL; release_sock(sk); sock_put(sk); @@ -1589,10 +1625,15 @@ static int isotp_init(struct sock *sk) so->tx.ll_dl = so->ll.tx_dl; so->rx.state = ISOTP_IDLE; so->tx.state = ISOTP_IDLE; + so->rx.buf = so->rx.sbuf; + so->tx.buf = so->tx.sbuf; + so->rx.buflen = DEFAULT_MAX_PDU_SIZE; + so->tx.buflen = DEFAULT_MAX_PDU_SIZE; + hrtimer_init(&so->rxtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT); so->rxtimer.function = isotp_rx_timer_handler; hrtimer_init(&so->txtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT); so->txtimer.function = isotp_tx_timer_handler; hrtimer_init(&so->txfrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT); @@ -1656,11 +1697,13 @@ static struct notifier_block canisotp_notifier = { static __init int isotp_module_init(void) { int err; - pr_info("can: isotp protocol\n"); + max_pdu_size = min(max_pdu_size, (unsigned int)MAX_PDU_SIZE); + + pr_info("can: isotp protocol (max_pdu_size %d)\n", max_pdu_size); err = can_proto_register(&isotp_can_proto); if (err < 0) pr_err("can: registration of isotp protocol failed %pe\n", ERR_PTR(err)); else -- 2.30.2
