Commit eb88531b authored Sep 27, 2020 by Vincent Mailhol Committed by Marc Kleine-Budde Oct 06, 2020

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>

parent d61469dc

include/uapi/linux/can/raw.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -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) */

net/can/raw.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -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;

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