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-rw-r--r--include/uapi/linux/can/isotp.h28
-rw-r--r--net/can/isotp.c12
2 files changed, 33 insertions, 7 deletions
diff --git a/include/uapi/linux/can/isotp.h b/include/uapi/linux/can/isotp.h
index c55935b64ccc..590f8aea2b6d 100644
--- a/include/uapi/linux/can/isotp.h
+++ b/include/uapi/linux/can/isotp.h
@@ -137,20 +137,16 @@ struct can_isotp_ll_options {
#define CAN_ISOTP_WAIT_TX_DONE 0x400 /* wait for tx completion */
#define CAN_ISOTP_SF_BROADCAST 0x800 /* 1-to-N functional addressing */
-/* default values */
+/* protocol machine default values */
#define CAN_ISOTP_DEFAULT_FLAGS 0
#define CAN_ISOTP_DEFAULT_EXT_ADDRESS 0x00
#define CAN_ISOTP_DEFAULT_PAD_CONTENT 0xCC /* prevent bit-stuffing */
-#define CAN_ISOTP_DEFAULT_FRAME_TXTIME 0
+#define CAN_ISOTP_DEFAULT_FRAME_TXTIME 50000 /* 50 micro seconds */
#define CAN_ISOTP_DEFAULT_RECV_BS 0
#define CAN_ISOTP_DEFAULT_RECV_STMIN 0x00
#define CAN_ISOTP_DEFAULT_RECV_WFTMAX 0
-#define CAN_ISOTP_DEFAULT_LL_MTU CAN_MTU
-#define CAN_ISOTP_DEFAULT_LL_TX_DL CAN_MAX_DLEN
-#define CAN_ISOTP_DEFAULT_LL_TX_FLAGS 0
-
/*
* Remark on CAN_ISOTP_DEFAULT_RECV_* values:
*
@@ -162,4 +158,24 @@ struct can_isotp_ll_options {
* consistency and copied directly into the flow control (FC) frame.
*/
+/* link layer default values => make use of Classical CAN frames */
+
+#define CAN_ISOTP_DEFAULT_LL_MTU CAN_MTU
+#define CAN_ISOTP_DEFAULT_LL_TX_DL CAN_MAX_DLEN
+#define CAN_ISOTP_DEFAULT_LL_TX_FLAGS 0
+
+/*
+ * The CAN_ISOTP_DEFAULT_FRAME_TXTIME has become a non-zero value as
+ * it only makes sense for isotp implementation tests to run without
+ * a N_As value. As user space applications usually do not set the
+ * frame_txtime element of struct can_isotp_options the new in-kernel
+ * default is very likely overwritten with zero when the sockopt()
+ * CAN_ISOTP_OPTS is invoked.
+ * To make sure that a N_As value of zero is only set intentional the
+ * value '0' is now interpreted as 'do not change the current value'.
+ * When a frame_txtime of zero is required for testing purposes this
+ * CAN_ISOTP_FRAME_TXTIME_ZERO u32 value has to be set in frame_txtime.
+ */
+#define CAN_ISOTP_FRAME_TXTIME_ZERO 0xFFFFFFFF
+
#endif /* !_UAPI_CAN_ISOTP_H */
diff --git a/net/can/isotp.c b/net/can/isotp.c
index d59f1758ac9c..47404ba59981 100644
--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -140,6 +140,7 @@ struct isotp_sock {
struct can_isotp_options opt;
struct can_isotp_fc_options rxfc, txfc;
struct can_isotp_ll_options ll;
+ u32 frame_txtime;
u32 force_tx_stmin;
u32 force_rx_stmin;
u32 cfecho; /* consecutive frame echo tag */
@@ -360,7 +361,7 @@ static int isotp_rcv_fc(struct isotp_sock *so, struct canfd_frame *cf, int ae)
so->tx_gap = ktime_set(0, 0);
/* add transmission time for CAN frame N_As */
- so->tx_gap = ktime_add_ns(so->tx_gap, so->opt.frame_txtime);
+ so->tx_gap = ktime_add_ns(so->tx_gap, so->frame_txtime);
/* add waiting time for consecutive frames N_Cs */
if (so->opt.flags & CAN_ISOTP_FORCE_TXSTMIN)
so->tx_gap = ktime_add_ns(so->tx_gap,
@@ -1293,6 +1294,14 @@ static int isotp_setsockopt_locked(struct socket *sock, int level, int optname,
/* no separate rx_ext_address is given => use ext_address */
if (!(so->opt.flags & CAN_ISOTP_RX_EXT_ADDR))
so->opt.rx_ext_address = so->opt.ext_address;
+
+ /* check for frame_txtime changes (0 => no changes) */
+ if (so->opt.frame_txtime) {
+ if (so->opt.frame_txtime == CAN_ISOTP_FRAME_TXTIME_ZERO)
+ so->frame_txtime = 0;
+ else
+ so->frame_txtime = so->opt.frame_txtime;
+ }
break;
case CAN_ISOTP_RECV_FC:
@@ -1498,6 +1507,7 @@ static int isotp_init(struct sock *sk)
so->opt.rxpad_content = CAN_ISOTP_DEFAULT_PAD_CONTENT;
so->opt.txpad_content = CAN_ISOTP_DEFAULT_PAD_CONTENT;
so->opt.frame_txtime = CAN_ISOTP_DEFAULT_FRAME_TXTIME;
+ so->frame_txtime = CAN_ISOTP_DEFAULT_FRAME_TXTIME;
so->rxfc.bs = CAN_ISOTP_DEFAULT_RECV_BS;
so->rxfc.stmin = CAN_ISOTP_DEFAULT_RECV_STMIN;
so->rxfc.wftmax = CAN_ISOTP_DEFAULT_RECV_WFTMAX;