diff options
| author | Oliver Hartkopp <socketcan@hartkopp.net> | 2026-02-01 15:33:21 +0100 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2026-02-05 11:58:40 +0100 |
| commit | 3ffecc14ec7ee8eb941e50c0076798a042924c62 (patch) | |
| tree | f1d09f5cf5ea5f006619c271065441352af0aac6 /net | |
| parent | 9f10374bb024593a611e6845847f0444841a231b (diff) | |
can: gw: use can_gw_hops instead of sk_buff::csum_start
As CAN skbs don't use IP checksums the skb->csum_start variable was used to
store the can-gw CAN frame time-to-live counter together with
skb->ip_summed set to CHECKSUM_UNNECESSARY.
Remove the 'hack' using the skb->csum_start variable and move the content
to can_skb_ext::can_gw_hops of the CAN skb extensions.
The module parameter 'max_hops' has been reduced to a single byte to fit
can_skb_ext::can_gw_hops as the maximum value to be stored is 6.
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://patch.msgid.link/20260201-can_skb_ext-v8-6-3635d790fe8b@hartkopp.net
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'net')
| -rw-r--r-- | net/can/gw.c | 23 |
1 files changed, 6 insertions, 17 deletions
diff --git a/net/can/gw.c b/net/can/gw.c index 816154a978c1..61a1e6b1b83f 100644 --- a/net/can/gw.c +++ b/net/can/gw.c @@ -71,8 +71,8 @@ MODULE_ALIAS(CAN_GW_NAME); #define CGW_MAX_HOPS 6 #define CGW_DEFAULT_HOPS 1 -static unsigned int max_hops __read_mostly = CGW_DEFAULT_HOPS; -module_param(max_hops, uint, 0444); +static unsigned char max_hops __read_mostly = CGW_DEFAULT_HOPS; +module_param(max_hops, byte, 0444); MODULE_PARM_DESC(max_hops, "maximum " CAN_GW_NAME " routing hops for CAN frames " "(valid values: " __stringify(CGW_MIN_HOPS) "-" @@ -480,19 +480,8 @@ static void can_can_gw_rcv(struct sk_buff *skb, void *data) /* Do not handle CAN frames routed more than 'max_hops' times. * In general we should never catch this delimiter which is intended * to cover a misconfiguration protection (e.g. circular CAN routes). - * - * The Controller Area Network controllers only accept CAN frames with - * correct CRCs - which are not visible in the controller registers. - * According to skbuff.h documentation the csum_start element for IP - * checksums is undefined/unused when ip_summed == CHECKSUM_UNNECESSARY. - * Only CAN skbs can be processed here which already have this property. */ - -#define cgw_hops(skb) ((skb)->csum_start) - - BUG_ON(skb->ip_summed != CHECKSUM_UNNECESSARY); - - if (cgw_hops(skb) >= max_hops) { + if (csx->can_gw_hops >= max_hops) { /* indicate deleted frames due to misconfiguration */ gwj->deleted_frames++; return; @@ -536,11 +525,11 @@ static void can_can_gw_rcv(struct sk_buff *skb, void *data) } /* put the incremented hop counter in the cloned skb */ - cgw_hops(nskb) = cgw_hops(skb) + 1; + ncsx->can_gw_hops = csx->can_gw_hops + 1; /* first processing of this CAN frame -> adjust to private hop limit */ - if (gwj->limit_hops && cgw_hops(nskb) == 1) - cgw_hops(nskb) = max_hops - gwj->limit_hops + 1; + if (gwj->limit_hops && ncsx->can_gw_hops == 1) + ncsx->can_gw_hops = max_hops - gwj->limit_hops + 1; nskb->dev = gwj->dst.dev; |