[PATCH can-next] can: gw: give feedback on missing CGW_FLAGS_CAN_IIF_TX_OK flag

[PATCH can-next] can: gw: give feedback on missing CGW_FLAGS_CAN_IIF_TX_OK flag

[Oliver Hartkopp]

To send CAN traffic back to the incoming interface a special flag has to
be set. When creating a routing job for identical interfaces without this
flag the rule is created but has no effect.

This patch adds an error return value in the case that the CAN interfaces
are identical but the CGW_FLAGS_CAN_IIF_TX_OK flag was not set.

Reported-by: Jannik Hartung <jannik.hartung@tu-bs.de>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
---
 net/can/gw.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/net/can/gw.c b/net/can/gw.c
index 23a3d89cad81..37528826935e 100644
--- a/net/can/gw.c
+++ b/net/can/gw.c
@@ -1137,10 +1137,17 @@ static int cgw_create_job(struct sk_buff *skb,  struct nlmsghdr *nlh,
 		goto out;
 
 	if (gwj->dst.dev->type != ARPHRD_CAN)
 		goto out;
 
+	/* is sending the skb back to the incoming interface intended? */
+	if (gwj->src.dev == gwj->dst.dev &&
+	    !(gwj->flags & CGW_FLAGS_CAN_IIF_TX_OK)) {
+		err = -EINVAL;
+		goto out;
+	}
+
 	ASSERT_RTNL();
 
 	err = cgw_register_filter(net, gwj);
 	if (!err)
 		hlist_add_head_rcu(&gwj->list, &net->can.cgw_list);
-- 
2.30.2

Re: [PATCH can-next] can: gw: give feedback on missing CGW_FLAGS_CAN_IIF_TX_OK flag

[Marc Kleine-Budde]

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On 25.01.2023 06:54:07, Oliver Hartkopp wrote:
> To send CAN traffic back to the incoming interface a special flag has to
> be set. When creating a routing job for identical interfaces without this
> flag the rule is created but has no effect.
> 
> This patch adds an error return value in the case that the CAN interfaces
> are identical but the CGW_FLAGS_CAN_IIF_TX_OK flag was not set.
> 
> Reported-by: Jannik Hartung <jannik.hartung@tu-bs.de>
> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>

Applied to can-next.

Thanks,
Marc

-- 
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