From: Oliver Hartkopp <socketcan@xxxxxxxxxxxx> 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. changes since v2: https://lore.kernel.org/all/20230313172510.3851-1-socketcan@xxxxxxxxxxxx - use ARRAY_SIZE() to reference DEFAULT_MAX_PDU_SIZE only at one place changes since v1: https://lore.kernel.org/all/20230311143446.3183-1-socketcan@xxxxxxxxxxxx - limit the minimum 'max_pdu_size' to 4095 to maintain the classic behavior before ISO 15765-2:2016 Link: https://github.com/raspberrypi/linux/issues/5371 Signed-off-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx> Link: https://lore.kernel.org/all/20230326115911.15094-1-socketcan@xxxxxxxxxxxx Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> --- net/can/isotp.c | 65 ++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 56 insertions(+), 9 deletions(-) diff --git a/net/can/isotp.c b/net/can/isotp.c index 9bc344851704..f1ea91772ae7 100644 --- a/net/can/isotp.c +++ b/net/can/isotp.c @@ -85,10 +85,21 @@ MODULE_ALIAS("can-proto-6"); /* 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 + +/* maximum PDU size before ISO 15765-2:2016 extension was 4095 */ +#define MAX_12BIT_PDU_SIZE 4095 + +/* 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 */ @@ -123,13 +134,15 @@ enum { }; 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 { @@ -503,7 +516,17 @@ static int isotp_rcv_ff(struct sock *sk, struct canfd_frame *cf, int ae) 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; @@ -807,7 +830,7 @@ static void isotp_create_fframe(struct canfd_frame *cf, struct isotp_sock *so, cf->data[0] = so->opt.ext_address; /* create N_PCI bytes with 12/32 bit FF_DL data length */ - if (so->tx.len > 4095) { + if (so->tx.len > MAX_12BIT_PDU_SIZE) { /* use 32 bit FF_DL notation */ cf->data[ae] = N_PCI_FF; cf->data[ae + 1] = 0; @@ -947,7 +970,17 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) 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; } @@ -1195,6 +1228,12 @@ static int isotp_release(struct socket *sock) 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; @@ -1591,6 +1630,11 @@ static int isotp_init(struct sock *sk) 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 = ARRAY_SIZE(so->rx.sbuf); + so->tx.buflen = ARRAY_SIZE(so->tx.sbuf); + 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); @@ -1658,7 +1702,10 @@ static __init int isotp_module_init(void) { int err; - pr_info("can: isotp protocol\n"); + max_pdu_size = max_t(unsigned int, max_pdu_size, MAX_12BIT_PDU_SIZE); + max_pdu_size = min_t(unsigned int, max_pdu_size, 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) base-commit: 4cee0fb9cc4b5477637fdeb2e965f5fc7d624622 -- 2.39.2
