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authorGravatar Nicolas Maier <nicolas.maier.dev@gmail.com> 2024-01-20 09:10:18 +0100
committerGravatar Marc Kleine-Budde <mkl@pengutronix.de> 2024-02-12 16:55:17 +0100
commitfec846fa7eddf7bb651bf88bd78c7db1410ae3b1 (patch)
tree4e8d090eb94914f01777cd65420040a14f69d6ae /net/can
parentMerge branch 'phy-package' (diff)
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can: bcm: add recvmsg flags for own, local and remote traffic
CAN RAW sockets allow userspace to tell if a received CAN frame comes from the same socket, another socket on the same host, or another host. See commit 1e55659ce6dd ("can-raw: add msg_flags to distinguish local traffic"). However, this feature is missing in CAN BCM sockets. Add the same feature to CAN BCM sockets. When reading a received frame (opcode RX_CHANGED) using recvmsg, two flags in msg->msg_flags may be set following the previous convention (from CAN RAW), to distinguish between 'own', 'local' and 'remote' CAN traffic. Update the documentation to reflect this change. Signed-off-by: Nicolas Maier <nicolas.maier.dev@gmail.com> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Link: https://lore.kernel.org/all/20240120081018.2319-1-socketcan@hartkopp.net Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Diffstat (limited to 'net/can')
-rw-r--r--net/can/bcm.c69
1 files changed, 57 insertions, 12 deletions
diff --git a/net/can/bcm.c b/net/can/bcm.c
index 9168114fc87f..27d5fcf0eac9 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -72,9 +72,11 @@
#define BCM_TIMER_SEC_MAX (400 * 24 * 60 * 60)
/* use of last_frames[index].flags */
+#define RX_LOCAL 0x10 /* frame was created on the local host */
+#define RX_OWN 0x20 /* frame was sent via the socket it was received on */
#define RX_RECV 0x40 /* received data for this element */
#define RX_THR 0x80 /* element not been sent due to throttle feature */
-#define BCM_CAN_FLAGS_MASK 0x3F /* to clean private flags after usage */
+#define BCM_CAN_FLAGS_MASK 0x0F /* to clean private flags after usage */
/* get best masking value for can_rx_register() for a given single can_id */
#define REGMASK(id) ((id & CAN_EFF_FLAG) ? \
@@ -138,6 +140,16 @@ static LIST_HEAD(bcm_notifier_list);
static DEFINE_SPINLOCK(bcm_notifier_lock);
static struct bcm_sock *bcm_busy_notifier;
+/* Return pointer to store the extra msg flags for bcm_recvmsg().
+ * We use the space of one unsigned int beyond the 'struct sockaddr_can'
+ * in skb->cb.
+ */
+static inline unsigned int *bcm_flags(struct sk_buff *skb)
+{
+ /* return pointer after struct sockaddr_can */
+ return (unsigned int *)(&((struct sockaddr_can *)skb->cb)[1]);
+}
+
static inline struct bcm_sock *bcm_sk(const struct sock *sk)
{
return (struct bcm_sock *)sk;
@@ -325,6 +337,7 @@ static void bcm_send_to_user(struct bcm_op *op, struct bcm_msg_head *head,
struct sock *sk = op->sk;
unsigned int datalen = head->nframes * op->cfsiz;
int err;
+ unsigned int *pflags;
skb = alloc_skb(sizeof(*head) + datalen, gfp_any());
if (!skb)
@@ -332,6 +345,14 @@ static void bcm_send_to_user(struct bcm_op *op, struct bcm_msg_head *head,
skb_put_data(skb, head, sizeof(*head));
+ /* ensure space for sockaddr_can and msg flags */
+ sock_skb_cb_check_size(sizeof(struct sockaddr_can) +
+ sizeof(unsigned int));
+
+ /* initialize msg flags */
+ pflags = bcm_flags(skb);
+ *pflags = 0;
+
if (head->nframes) {
/* CAN frames starting here */
firstframe = (struct canfd_frame *)skb_tail_pointer(skb);
@@ -344,8 +365,14 @@ static void bcm_send_to_user(struct bcm_op *op, struct bcm_msg_head *head,
* relevant for updates that are generated by the
* BCM, where nframes is 1
*/
- if (head->nframes == 1)
+ if (head->nframes == 1) {
+ if (firstframe->flags & RX_LOCAL)
+ *pflags |= MSG_DONTROUTE;
+ if (firstframe->flags & RX_OWN)
+ *pflags |= MSG_CONFIRM;
+
firstframe->flags &= BCM_CAN_FLAGS_MASK;
+ }
}
if (has_timestamp) {
@@ -360,7 +387,6 @@ static void bcm_send_to_user(struct bcm_op *op, struct bcm_msg_head *head,
* containing the interface index.
*/
- sock_skb_cb_check_size(sizeof(struct sockaddr_can));
addr = (struct sockaddr_can *)skb->cb;
memset(addr, 0, sizeof(*addr));
addr->can_family = AF_CAN;
@@ -444,7 +470,7 @@ static void bcm_rx_changed(struct bcm_op *op, struct canfd_frame *data)
op->frames_filtered = op->frames_abs = 0;
/* this element is not throttled anymore */
- data->flags &= (BCM_CAN_FLAGS_MASK|RX_RECV);
+ data->flags &= ~RX_THR;
memset(&head, 0, sizeof(head));
head.opcode = RX_CHANGED;
@@ -465,13 +491,17 @@ static void bcm_rx_changed(struct bcm_op *op, struct canfd_frame *data)
*/
static void bcm_rx_update_and_send(struct bcm_op *op,
struct canfd_frame *lastdata,
- const struct canfd_frame *rxdata)
+ const struct canfd_frame *rxdata,
+ unsigned char traffic_flags)
{
memcpy(lastdata, rxdata, op->cfsiz);
/* mark as used and throttled by default */
lastdata->flags |= (RX_RECV|RX_THR);
+ /* add own/local/remote traffic flags */
+ lastdata->flags |= traffic_flags;
+
/* throttling mode inactive ? */
if (!op->kt_ival2) {
/* send RX_CHANGED to the user immediately */
@@ -508,7 +538,8 @@ rx_changed_settime:
* received data stored in op->last_frames[]
*/
static void bcm_rx_cmp_to_index(struct bcm_op *op, unsigned int index,
- const struct canfd_frame *rxdata)
+ const struct canfd_frame *rxdata,
+ unsigned char traffic_flags)
{
struct canfd_frame *cf = op->frames + op->cfsiz * index;
struct canfd_frame *lcf = op->last_frames + op->cfsiz * index;
@@ -521,7 +552,7 @@ static void bcm_rx_cmp_to_index(struct bcm_op *op, unsigned int index,
if (!(lcf->flags & RX_RECV)) {
/* received data for the first time => send update to user */
- bcm_rx_update_and_send(op, lcf, rxdata);
+ bcm_rx_update_and_send(op, lcf, rxdata, traffic_flags);
return;
}
@@ -529,7 +560,7 @@ static void bcm_rx_cmp_to_index(struct bcm_op *op, unsigned int index,
for (i = 0; i < rxdata->len; i += 8) {
if ((get_u64(cf, i) & get_u64(rxdata, i)) !=
(get_u64(cf, i) & get_u64(lcf, i))) {
- bcm_rx_update_and_send(op, lcf, rxdata);
+ bcm_rx_update_and_send(op, lcf, rxdata, traffic_flags);
return;
}
}
@@ -537,7 +568,7 @@ static void bcm_rx_cmp_to_index(struct bcm_op *op, unsigned int index,
if (op->flags & RX_CHECK_DLC) {
/* do a real check in CAN frame length */
if (rxdata->len != lcf->len) {
- bcm_rx_update_and_send(op, lcf, rxdata);
+ bcm_rx_update_and_send(op, lcf, rxdata, traffic_flags);
return;
}
}
@@ -644,6 +675,7 @@ static void bcm_rx_handler(struct sk_buff *skb, void *data)
struct bcm_op *op = (struct bcm_op *)data;
const struct canfd_frame *rxframe = (struct canfd_frame *)skb->data;
unsigned int i;
+ unsigned char traffic_flags;
if (op->can_id != rxframe->can_id)
return;
@@ -673,15 +705,24 @@ static void bcm_rx_handler(struct sk_buff *skb, void *data)
return;
}
+ /* compute flags to distinguish between own/local/remote CAN traffic */
+ traffic_flags = 0;
+ if (skb->sk) {
+ traffic_flags |= RX_LOCAL;
+ if (skb->sk == op->sk)
+ traffic_flags |= RX_OWN;
+ }
+
if (op->flags & RX_FILTER_ID) {
/* the easiest case */
- bcm_rx_update_and_send(op, op->last_frames, rxframe);
+ bcm_rx_update_and_send(op, op->last_frames, rxframe,
+ traffic_flags);
goto rx_starttimer;
}
if (op->nframes == 1) {
/* simple compare with index 0 */
- bcm_rx_cmp_to_index(op, 0, rxframe);
+ bcm_rx_cmp_to_index(op, 0, rxframe, traffic_flags);
goto rx_starttimer;
}
@@ -698,7 +739,8 @@ static void bcm_rx_handler(struct sk_buff *skb, void *data)
if ((get_u64(op->frames, 0) & get_u64(rxframe, 0)) ==
(get_u64(op->frames, 0) &
get_u64(op->frames + op->cfsiz * i, 0))) {
- bcm_rx_cmp_to_index(op, i, rxframe);
+ bcm_rx_cmp_to_index(op, i, rxframe,
+ traffic_flags);
break;
}
}
@@ -1675,6 +1717,9 @@ static int bcm_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
}
+ /* assign the flags that have been recorded in bcm_send_to_user() */
+ msg->msg_flags |= *(bcm_flags(skb));
+
skb_free_datagram(sk, skb);
return size;