From: Vincent Mailhol <mailhol.vincent@xxxxxxxxxx> 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@xxxxxxxxxx> Link: https://lore.kernel.org/r/20200926162527.270030-1-mailhol.vincent@xxxxxxxxxx Acked-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx> Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> --- include/uapi/linux/can/raw.h | 3 +++ net/can/raw.c | 4 ++++ 2 files changed, 7 insertions(+) diff --git a/include/uapi/linux/can/raw.h b/include/uapi/linux/can/raw.h index 6a11d308eb5c..3386aa81fdf2 100644 --- a/include/uapi/linux/can/raw.h +++ b/include/uapi/linux/can/raw.h @@ -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) */ diff --git a/net/can/raw.c b/net/can/raw.c index 24db4b4afdc7..ea70850f9152 100644 --- a/net/can/raw.c +++ b/net/can/raw.c @@ -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; -- 2.28.0
