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-rw-r--r--Documentation/networking/can.txt20
-rw-r--r--include/uapi/linux/can/raw.h1
-rw-r--r--net/can/raw.c31
3 files changed, 49 insertions, 3 deletions
diff --git a/Documentation/networking/can.txt b/Documentation/networking/can.txt
index 0a2859a8ee7e..5abad1e921ca 100644
--- a/Documentation/networking/can.txt
+++ b/Documentation/networking/can.txt
@@ -22,7 +22,8 @@ This file contains
4.1.3 RAW socket option CAN_RAW_LOOPBACK
4.1.4 RAW socket option CAN_RAW_RECV_OWN_MSGS
4.1.5 RAW socket option CAN_RAW_FD_FRAMES
- 4.1.6 RAW socket returned message flags
+ 4.1.6 RAW socket option CAN_RAW_JOIN_FILTERS
+ 4.1.7 RAW socket returned message flags
4.2 Broadcast Manager protocol sockets (SOCK_DGRAM)
4.2.1 Broadcast Manager operations
4.2.2 Broadcast Manager message flags
@@ -601,7 +602,22 @@ solution for a couple of reasons:
CAN FD frames by checking if the device maximum transfer unit is CANFD_MTU.
The CAN device MTU can be retrieved e.g. with a SIOCGIFMTU ioctl() syscall.
- 4.1.6 RAW socket returned message flags
+ 4.1.6 RAW socket option CAN_RAW_JOIN_FILTERS
+
+ The CAN_RAW socket can set multiple CAN identifier specific filters that
+ lead to multiple filters in the af_can.c filter processing. These filters
+ are indenpendent from each other which leads to logical OR'ed filters when
+ applied (see 4.1.1).
+
+ This socket option joines the given CAN filters in the way that only CAN
+ frames are passed to user space that matched *all* given CAN filters. The
+ semantic for the applied filters is therefore changed to a logical AND.
+
+ This is useful especially when the filterset is a combination of filters
+ where the CAN_INV_FILTER flag is set in order to notch single CAN IDs or
+ CAN ID ranges from the incoming traffic.
+
+ 4.1.7 RAW socket returned message flags
When using recvmsg() call, the msg->msg_flags may contain following flags:
diff --git a/include/uapi/linux/can/raw.h b/include/uapi/linux/can/raw.h
index 78ec76fd89a6..8735f1080385 100644
--- a/include/uapi/linux/can/raw.h
+++ b/include/uapi/linux/can/raw.h
@@ -57,6 +57,7 @@ enum {
CAN_RAW_LOOPBACK, /* local loopback (default:on) */
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 */
};
#endif /* !_UAPI_CAN_RAW_H */
diff --git a/net/can/raw.c b/net/can/raw.c
index 0c8d537b59b8..31b9748cbb4e 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -77,6 +77,7 @@ MODULE_ALIAS("can-proto-1");
struct uniqframe {
ktime_t tstamp;
const struct sk_buff *skb;
+ unsigned int join_rx_count;
};
struct raw_sock {
@@ -87,6 +88,7 @@ struct raw_sock {
int loopback;
int recv_own_msgs;
int fd_frames;
+ int join_filters;
int count; /* number of active filters */
struct can_filter dfilter; /* default/single filter */
struct can_filter *filter; /* pointer to filter(s) */
@@ -132,10 +134,21 @@ static void raw_rcv(struct sk_buff *oskb, void *data)
/* eliminate multiple filter matches for the same skb */
if (this_cpu_ptr(ro->uniq)->skb == oskb &&
ktime_equal(this_cpu_ptr(ro->uniq)->tstamp, oskb->tstamp)) {
- return;
+ if (ro->join_filters) {
+ this_cpu_inc(ro->uniq->join_rx_count);
+ /* drop frame until all enabled filters matched */
+ if (this_cpu_ptr(ro->uniq)->join_rx_count < ro->count)
+ return;
+ } else {
+ return;
+ }
} else {
this_cpu_ptr(ro->uniq)->skb = oskb;
this_cpu_ptr(ro->uniq)->tstamp = oskb->tstamp;
+ this_cpu_ptr(ro->uniq)->join_rx_count = 1;
+ /* drop first frame to check all enabled filters? */
+ if (ro->join_filters && ro->count > 1)
+ return;
}
/* clone the given skb to be able to enqueue it into the rcv queue */
@@ -311,6 +324,7 @@ static int raw_init(struct sock *sk)
ro->loopback = 1;
ro->recv_own_msgs = 0;
ro->fd_frames = 0;
+ ro->join_filters = 0;
/* alloc_percpu provides zero'ed memory */
ro->uniq = alloc_percpu(struct uniqframe);
@@ -604,6 +618,15 @@ static int raw_setsockopt(struct socket *sock, int level, int optname,
break;
+ case CAN_RAW_JOIN_FILTERS:
+ if (optlen != sizeof(ro->join_filters))
+ return -EINVAL;
+
+ if (copy_from_user(&ro->join_filters, optval, optlen))
+ return -EFAULT;
+
+ break;
+
default:
return -ENOPROTOOPT;
}
@@ -668,6 +691,12 @@ static int raw_getsockopt(struct socket *sock, int level, int optname,
val = &ro->fd_frames;
break;
+ case CAN_RAW_JOIN_FILTERS:
+ if (len > sizeof(int))
+ len = sizeof(int);
+ val = &ro->join_filters;
+ break;
+
default:
return -ENOPROTOOPT;
}