The ISO15765-2 standard supports to take the PDUs communication parameters
blocksize (BS) and Separation Time minimum (STmin) either from the first
received flow control (FC) "static" or from every received FC "dynamic".
Add a new CAN_ISOTP_DYN_FC_PARMS flag to support dynamic FC parameters.
Signed-off-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>
---
include/uapi/linux/can/isotp.h | 1 +
net/can/isotp.c | 5 +++--
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/include/uapi/linux/can/isotp.h b/include/uapi/linux/can/isotp.h
index 439c982f7e81..6cde62371b6f 100644
--- a/include/uapi/linux/can/isotp.h
+++ b/include/uapi/linux/can/isotp.h
@@ -135,10 +135,11 @@ struct can_isotp_ll_options {
#define CAN_ISOTP_FORCE_RXSTMIN 0x0100 /* ignore CFs depending on rx stmin */
#define CAN_ISOTP_RX_EXT_ADDR 0x0200 /* different rx extended addressing */
#define CAN_ISOTP_WAIT_TX_DONE 0x0400 /* wait for tx completion */
#define CAN_ISOTP_SF_BROADCAST 0x0800 /* 1-to-N functional addressing */
#define CAN_ISOTP_CF_BROADCAST 0x1000 /* 1-to-N transmission w/o FC */
+#define CAN_ISOTP_DYN_FC_PARMS 0x2000 /* dynamic FC parameters BS/STmin */
/* protocol machine 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 d1c6f206f429..25bac0fafc83 100644
--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -379,12 +379,13 @@ static int isotp_rcv_fc(struct isotp_sock *so, struct canfd_frame *cf, int ae)
so->tx.state = ISOTP_IDLE;
wake_up_interruptible(&so->wait);
return 1;
}
- /* get communication parameters only from the first FC frame */
- if (so->tx.state == ISOTP_WAIT_FIRST_FC) {
+ /* get static/dynamic communication params from first/every FC frame */
+ if (so->tx.state == ISOTP_WAIT_FIRST_FC ||
+ so->opt.flags & CAN_ISOTP_DYN_FC_PARMS) {
so->txfc.bs = cf->data[ae + 1];
so->txfc.stmin = cf->data[ae + 2];
/* fix wrong STmin values according spec */
if (so->txfc.stmin > 0x7F &&
--
2.39.2
