From c7b74967799b1af52b3045d69d4c26836b2d41de Mon Sep 17 00:00:00 2001 From: Oliver Hartkopp Date: Fri, 20 Nov 2020 11:04:44 +0100 Subject: can: replace can_dlc as variable/element for payload length The naming of can_dlc as element of struct can_frame and also as variable name is misleading as it claims to be a 'data length CODE' but in reality it always was a plain data length. With the indroduction of a new 'len' element in struct can_frame we can now remove can_dlc as name and make clear which of the former uses was a plain length (-> 'len') or a data length code (-> 'dlc') value. Signed-off-by: Oliver Hartkopp Link: https://lore.kernel.org/r/20201120100444.3199-1-socketcan@hartkopp.net [mkl: gs_usb: keep struct gs_host_frame::can_dlc as is] Signed-off-by: Marc Kleine-Budde --- net/can/af_can.c | 2 +- net/can/gw.c | 2 +- net/can/j1939/main.c | 4 ++-- 3 files changed, 4 insertions(+), 4 deletions(-) (limited to 'net') diff --git a/net/can/af_can.c b/net/can/af_can.c index 5d124c155904..963bd7145517 100644 --- a/net/can/af_can.c +++ b/net/can/af_can.c @@ -888,7 +888,7 @@ static __init int can_init(void) int err; /* check for correct padding to be able to use the structs similarly */ - BUILD_BUG_ON(offsetof(struct can_frame, can_dlc) != + BUILD_BUG_ON(offsetof(struct can_frame, len) != offsetof(struct canfd_frame, len) || offsetof(struct can_frame, data) != offsetof(struct canfd_frame, data)); diff --git a/net/can/gw.c b/net/can/gw.c index 6b790b6ff8d2..de5e8859ec9b 100644 --- a/net/can/gw.c +++ b/net/can/gw.c @@ -207,7 +207,7 @@ static void canframecpy(struct canfd_frame *dst, struct can_frame *src) */ dst->can_id = src->can_id; - dst->len = src->can_dlc; + dst->len = src->len; *(u64 *)dst->data = *(u64 *)src->data; } diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c index 137054bff9ec..bb914d8b4216 100644 --- a/net/can/j1939/main.c +++ b/net/can/j1939/main.c @@ -62,7 +62,7 @@ static void j1939_can_recv(struct sk_buff *iskb, void *data) skb_pull(skb, J1939_CAN_HDR); /* fix length, set to dlc, with 8 maximum */ - skb_trim(skb, min_t(uint8_t, cf->can_dlc, 8)); + skb_trim(skb, min_t(uint8_t, cf->len, 8)); /* set addr */ skcb = j1939_skb_to_cb(skb); @@ -335,7 +335,7 @@ int j1939_send_one(struct j1939_priv *priv, struct sk_buff *skb) canid |= skcb->addr.da << 8; cf->can_id = canid; - cf->can_dlc = dlc; + cf->len = dlc; return can_send(skb, 1); -- cgit v1.2.3 From 94c23097f991cd4568388564b3d2816b0b83f924 Mon Sep 17 00:00:00 2001 From: Oliver Hartkopp Date: Thu, 19 Nov 2020 09:49:21 +0100 Subject: can: gw: support modification of Classical CAN DLCs 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 Link: https://lore.kernel.org/r/20201119084921.2621-1-socketcan@hartkopp.net Signed-off-by: Marc Kleine-Budde --- include/uapi/linux/can/gw.h | 4 +-- net/can/gw.c | 78 ++++++++++++++++++++++++++++++++++++++++----- 2 files changed, 72 insertions(+), 10 deletions(-) (limited to 'net') 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; -- cgit v1.2.3