can: raw: add CAN XL support

Enable CAN_RAW sockets to read and write CAN XL frames analogue to the
CAN FD extension (new CAN_RAW_XL_FRAMES sockopt).

A CAN XL network interface is capable to handle Classical CAN, CAN FD and
CAN XL frames. When CAN_RAW_XL_FRAMES is enabled, the CAN_RAW socket checks
whether the addressed CAN network interface is capable to handle the
provided CAN frame.

In opposite to the fixed number of bytes for
- CAN frames (CAN_MTU = sizeof(struct can_frame))
- CAN FD frames (CANFD_MTU = sizeof(struct can_frame))
the number of bytes when reading/writing CAN XL frames depends on the
number of data bytes. For efficiency reasons the length of the struct
canxl_frame is truncated to the needed size for read/write operations.
This leads to a calculated size of CANXL_HDR_SIZE + canxl_frame::len which
is enforced on write() operations and guaranteed on read() operations.

NB: Valid length values are 1 .. 2048 (CANXL_MIN_DLEN .. CANXL_MAX_DLEN).

Acked-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/all/20220912170725.120748-8-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/include/uapi/linux/can/raw.h b/include/uapi/linux/can/raw.h
index 3386aa81fdf2f1f76dbc2789bd9ed2bc43c32fb1..ff12f525c37cebcf6442344b78af91e78b4cf955 100644 (file)
--- a/include/uapi/linux/can/raw.h
+++ b/include/uapi/linux/can/raw.h
@@ -62,6 +62,7 @@ enum {
        CAN_RAW_RECV_OWN_MSGS,  /* receive my own msgs (default:off) */
        CAN_RAW_FD_FRAMES,      /* allow CAN FD frames (default:off) */
        CAN_RAW_JOIN_FILTERS,   /* all filters must match to trigger */
+       CAN_RAW_XL_FRAMES,      /* allow CAN XL frames (default:off) */
 };
 
 #endif /* !_UAPI_CAN_RAW_H */

diff --git a/net/can/raw.c b/net/can/raw.c
index e7dfa3584e29cc1e4a63727b071729c7245d9e25..3eb7d3e2b541f2ba40deaecde15bb58bdf6fbfc1 100644 (file)
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -50,6 +50,7 @@
 #include <linux/skbuff.h>
 #include <linux/can.h>
 #include <linux/can/core.h>
+#include <linux/can/dev.h> /* for can_is_canxl_dev_mtu() */
 #include <linux/can/skb.h>
 #include <linux/can/raw.h>
 #include <net/sock.h>
@@ -87,6 +88,7 @@ struct raw_sock {
        int loopback;
        int recv_own_msgs;
        int fd_frames;
+       int xl_frames;
        int join_filters;
        int count;                 /* number of active filters */
        struct can_filter dfilter; /* default/single filter */
@@ -129,8 +131,9 @@ static void raw_rcv(struct sk_buff *oskb, void *data)
        if (!ro->recv_own_msgs && oskb->sk == sk)
                return;
 
-       /* do not pass non-CAN2.0 frames to a legacy socket */
-       if (!ro->fd_frames && oskb->len != CAN_MTU)
+       /* make sure to not pass oversized frames to the socket */
+       if ((can_is_canfd_skb(oskb) && !ro->fd_frames && !ro->xl_frames) ||
+           (can_is_canxl_skb(oskb) && !ro->xl_frames))
                return;
 
        /* eliminate multiple filter matches for the same skb */
@@ -345,6 +348,7 @@ static int raw_init(struct sock *sk)
        ro->loopback         = 1;
        ro->recv_own_msgs    = 0;
        ro->fd_frames        = 0;
+       ro->xl_frames        = 0;
        ro->join_filters     = 0;
 
        /* alloc_percpu provides zero'ed memory */
@@ -668,6 +672,15 @@ static int raw_setsockopt(struct socket *sock, int level, int optname,
 
                break;
 
+       case CAN_RAW_XL_FRAMES:
+               if (optlen != sizeof(ro->xl_frames))
+                       return -EINVAL;
+
+               if (copy_from_sockptr(&ro->xl_frames, optval, optlen))
+                       return -EFAULT;
+
+               break;
+
        case CAN_RAW_JOIN_FILTERS:
                if (optlen != sizeof(ro->join_filters))
                        return -EINVAL;
@@ -750,6 +763,12 @@ static int raw_getsockopt(struct socket *sock, int level, int optname,
                val = &ro->fd_frames;
                break;
 
+       case CAN_RAW_XL_FRAMES:
+               if (len > sizeof(int))
+                       len = sizeof(int);
+               val = &ro->xl_frames;
+               break;
+
        case CAN_RAW_JOIN_FILTERS:
                if (len > sizeof(int))
                        len = sizeof(int);
@@ -775,7 +794,11 @@ static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
        struct sk_buff *skb;
        struct net_device *dev;
        int ifindex;
-       int err;
+       int err = -EINVAL;
+
+       /* check for valid CAN frame sizes */
+       if (size < CANXL_HDR_SIZE + CANXL_MIN_DLEN || size > CANXL_MTU)
+               return -EINVAL;
 
        if (msg->msg_name) {
                DECLARE_SOCKADDR(struct sockaddr_can *, addr, msg->msg_name);
@@ -795,15 +818,6 @@ static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
        if (!dev)
                return -ENXIO;
 
-       err = -EINVAL;
-       if (ro->fd_frames && dev->mtu == CANFD_MTU) {
-               if (unlikely(size != CANFD_MTU && size != CAN_MTU))
-                       goto put_dev;
-       } else {
-               if (unlikely(size != CAN_MTU))
-                       goto put_dev;
-       }
-
        skb = sock_alloc_send_skb(sk, size + sizeof(struct can_skb_priv),
                                  msg->msg_flags & MSG_DONTWAIT, &err);
        if (!skb)
@@ -813,10 +827,27 @@ static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
        can_skb_prv(skb)->ifindex = dev->ifindex;
        can_skb_prv(skb)->skbcnt = 0;
 
+       /* fill the skb before testing for valid CAN frames */
        err = memcpy_from_msg(skb_put(skb, size), msg, size);
        if (err < 0)
                goto free_skb;
 
+       err = -EINVAL;
+       if (ro->xl_frames && can_is_canxl_dev_mtu(dev->mtu)) {
+               /* CAN XL, CAN FD and Classical CAN */
+               if (!can_is_canxl_skb(skb) && !can_is_canfd_skb(skb) &&
+                   !can_is_can_skb(skb))
+                       goto free_skb;
+       } else if (ro->fd_frames && dev->mtu == CANFD_MTU) {
+               /* CAN FD and Classical CAN */
+               if (!can_is_canfd_skb(skb) && !can_is_can_skb(skb))
+                       goto free_skb;
+       } else {
+               /* Classical CAN */
+               if (!can_is_can_skb(skb))
+                       goto free_skb;
+       }
+
        sockcm_init(&sockc, sk);
        if (msg->msg_controllen) {
                err = sock_cmsg_send(sk, msg, &sockc);