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Date: Fri, 20 Nov 2020 14:33:04 +0100
From: Marc Kleine-Budde <mkl@...gutronix.de>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net, kuba@...nel.org, linux-can@...r.kernel.org,
kernel@...gutronix.de, Oliver Hartkopp <socketcan@...tkopp.net>,
Marc Kleine-Budde <mkl@...gutronix.de>
Subject: [net-next 11/25] can: gw: support modification of Classical CAN DLCs
From: Oliver Hartkopp <socketcan@...tkopp.net>
Add support for data length code modifications for Classical CAN.
The netlink configuration interface always allowed to pass any value
that fits into a byte, therefore only the modification process had to be
extended to handle the raw DLC represenation of Classical CAN frames.
When a DLC value from 0 .. F is provided for Classical CAN frame
modifications the 'len' value is modified as-is with the exception that
potentially existing 9 .. F DLC values in the len8_dlc element are moved
to the 'len' element for the modification operation by mod_retrieve_ccdlc().
After the modification the Classical CAN frame DLC information is brought
back into the correct format by mod_store_ccdlc() which is filling 'len'
and 'len8_dlc' accordingly.
Signed-off-by: Oliver Hartkopp <socketcan@...tkopp.net>
Link: https://lore.kernel.org/r/20201119084921.2621-1-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
---
include/uapi/linux/can/gw.h | 4 +-
net/can/gw.c | 78 +++++++++++++++++++++++++++++++++----
2 files changed, 72 insertions(+), 10 deletions(-)
diff --git a/include/uapi/linux/can/gw.h b/include/uapi/linux/can/gw.h
index c2190bbe21d8..e4f0957554f3 100644
--- a/include/uapi/linux/can/gw.h
+++ b/include/uapi/linux/can/gw.h
@@ -98,8 +98,8 @@ enum {
/* CAN frame elements that are affected by curr. 3 CAN frame modifications */
#define CGW_MOD_ID 0x01
-#define CGW_MOD_DLC 0x02 /* contains the data length in bytes */
-#define CGW_MOD_LEN CGW_MOD_DLC /* CAN FD length representation */
+#define CGW_MOD_DLC 0x02 /* Classical CAN data length code */
+#define CGW_MOD_LEN CGW_MOD_DLC /* CAN FD (plain) data length */
#define CGW_MOD_DATA 0x04
#define CGW_MOD_FLAGS 0x08 /* CAN FD flags */
diff --git a/net/can/gw.c b/net/can/gw.c
index de5e8859ec9b..8598d9da0e5f 100644
--- a/net/can/gw.c
+++ b/net/can/gw.c
@@ -199,6 +199,68 @@ static void mod_set_fddata(struct canfd_frame *cf, struct cf_mod *mod)
memcpy(cf->data, mod->modframe.set.data, CANFD_MAX_DLEN);
}
+/* retrieve valid CC DLC value and store it into 'len' */
+static void mod_retrieve_ccdlc(struct canfd_frame *cf)
+{
+ struct can_frame *ccf = (struct can_frame *)cf;
+
+ /* len8_dlc is only valid if len == CAN_MAX_DLEN */
+ if (ccf->len != CAN_MAX_DLEN)
+ return;
+
+ /* do we have a valid len8_dlc value from 9 .. 15 ? */
+ if (ccf->len8_dlc > CAN_MAX_DLEN && ccf->len8_dlc <= CAN_MAX_RAW_DLC)
+ ccf->len = ccf->len8_dlc;
+}
+
+/* convert valid CC DLC value in 'len' into struct can_frame elements */
+static void mod_store_ccdlc(struct canfd_frame *cf)
+{
+ struct can_frame *ccf = (struct can_frame *)cf;
+
+ /* clear potential leftovers */
+ ccf->len8_dlc = 0;
+
+ /* plain data length 0 .. 8 - that was easy */
+ if (ccf->len <= CAN_MAX_DLEN)
+ return;
+
+ /* potentially broken values are catched in can_can_gw_rcv() */
+ if (ccf->len > CAN_MAX_RAW_DLC)
+ return;
+
+ /* we have a valid dlc value from 9 .. 15 in ccf->len */
+ ccf->len8_dlc = ccf->len;
+ ccf->len = CAN_MAX_DLEN;
+}
+
+static void mod_and_ccdlc(struct canfd_frame *cf, struct cf_mod *mod)
+{
+ mod_retrieve_ccdlc(cf);
+ mod_and_len(cf, mod);
+ mod_store_ccdlc(cf);
+}
+
+static void mod_or_ccdlc(struct canfd_frame *cf, struct cf_mod *mod)
+{
+ mod_retrieve_ccdlc(cf);
+ mod_or_len(cf, mod);
+ mod_store_ccdlc(cf);
+}
+
+static void mod_xor_ccdlc(struct canfd_frame *cf, struct cf_mod *mod)
+{
+ mod_retrieve_ccdlc(cf);
+ mod_xor_len(cf, mod);
+ mod_store_ccdlc(cf);
+}
+
+static void mod_set_ccdlc(struct canfd_frame *cf, struct cf_mod *mod)
+{
+ mod_set_len(cf, mod);
+ mod_store_ccdlc(cf);
+}
+
static void canframecpy(struct canfd_frame *dst, struct can_frame *src)
{
/* Copy the struct members separately to ensure that no uninitialized
@@ -842,8 +904,8 @@ static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
if (mb.modtype & CGW_MOD_ID)
mod->modfunc[modidx++] = mod_and_id;
- if (mb.modtype & CGW_MOD_LEN)
- mod->modfunc[modidx++] = mod_and_len;
+ if (mb.modtype & CGW_MOD_DLC)
+ mod->modfunc[modidx++] = mod_and_ccdlc;
if (mb.modtype & CGW_MOD_DATA)
mod->modfunc[modidx++] = mod_and_data;
@@ -858,8 +920,8 @@ static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
if (mb.modtype & CGW_MOD_ID)
mod->modfunc[modidx++] = mod_or_id;
- if (mb.modtype & CGW_MOD_LEN)
- mod->modfunc[modidx++] = mod_or_len;
+ if (mb.modtype & CGW_MOD_DLC)
+ mod->modfunc[modidx++] = mod_or_ccdlc;
if (mb.modtype & CGW_MOD_DATA)
mod->modfunc[modidx++] = mod_or_data;
@@ -874,8 +936,8 @@ static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
if (mb.modtype & CGW_MOD_ID)
mod->modfunc[modidx++] = mod_xor_id;
- if (mb.modtype & CGW_MOD_LEN)
- mod->modfunc[modidx++] = mod_xor_len;
+ if (mb.modtype & CGW_MOD_DLC)
+ mod->modfunc[modidx++] = mod_xor_ccdlc;
if (mb.modtype & CGW_MOD_DATA)
mod->modfunc[modidx++] = mod_xor_data;
@@ -890,8 +952,8 @@ static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
if (mb.modtype & CGW_MOD_ID)
mod->modfunc[modidx++] = mod_set_id;
- if (mb.modtype & CGW_MOD_LEN)
- mod->modfunc[modidx++] = mod_set_len;
+ if (mb.modtype & CGW_MOD_DLC)
+ mod->modfunc[modidx++] = mod_set_ccdlc;
if (mb.modtype & CGW_MOD_DATA)
mod->modfunc[modidx++] = mod_set_data;
--
2.29.2
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