can: raw: add missing error queue support

Error queue are not yet implemented in CAN-raw sockets.

The problem: a userland call to recvmsg(soc, msg, MSG_ERRQUEUE) on a
CAN-raw socket would unqueue messages from the normal queue without
any kind of error or warning. As such, it prevented CAN drivers from
using the functionalities that relies on the error queue such as
skb_tx_timestamp().

SCM_CAN_RAW_ERRQUEUE is defined as the type for the CAN raw error
queue. SCM stands for "Socket control messages". The name is inspired
from SCM_J1939_ERRQUEUE of include/uapi/linux/can/j1939.h.

Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://lore.kernel.org/r/20200926162527.270030-1-mailhol.vincent@wanadoo.fr
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Vincent Mailhol 2020-09-27 01:24:31 +09:00 committed by Marc Kleine-Budde
parent d61469dc87
commit eb88531bdb
2 changed files with 7 additions and 0 deletions

View File

@ -49,6 +49,9 @@
#include <linux/can.h>
#define SOL_CAN_RAW (SOL_CAN_BASE + CAN_RAW)
enum {
SCM_CAN_RAW_ERRQUEUE = 1,
};
/* for socket options affecting the socket (not the global system) */

View File

@ -804,6 +804,10 @@ static int raw_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
noblock = flags & MSG_DONTWAIT;
flags &= ~MSG_DONTWAIT;
if (flags & MSG_ERRQUEUE)
return sock_recv_errqueue(sk, msg, size,
SOL_CAN_RAW, SCM_CAN_RAW_ERRQUEUE);
skb = skb_recv_datagram(sk, flags, noblock, &err);
if (!skb)
return err;