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authorOliver Hartkopp <socketcan@hartkopp.net>2015-04-01 08:50:28 +0300
committerMarc Kleine-Budde <mkl@pengutronix.de>2015-04-01 12:27:41 +0300
commit514ac99c64b22d83b52dfee3b8becaa69a92bc4a (patch)
treedc44e61b13c9c7279ad7b5be1195f5cebeb422c2
parenta0bc163a7cf2ceb413a76cfd7149c6591db829ea (diff)
downloadlinux-514ac99c64b22d83b52dfee3b8becaa69a92bc4a.tar.xz
can: fix multiple delivery of a single CAN frame for overlapping CAN 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. This patch makes sure that every CAN frame which is filtered for a specific socket is only delivered once to the user space. This is independent from the number of matching CAN filters of this socket. As the raw_rcv() function is executed from NET_RX softirq the introduced variables are implemented as per-CPU variables to avoid extensive locking at CAN frame reception time. Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
-rw-r--r--net/can/raw.c21
1 files changed, 21 insertions, 0 deletions
diff --git a/net/can/raw.c b/net/can/raw.c
index 63ffdb0f3a23..0c8d537b59b8 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -74,6 +74,11 @@ MODULE_ALIAS("can-proto-1");
* storing the single filter in dfilter, to avoid using dynamic memory.
*/
+struct uniqframe {
+ ktime_t tstamp;
+ const struct sk_buff *skb;
+};
+
struct raw_sock {
struct sock sk;
int bound;
@@ -86,6 +91,7 @@ struct raw_sock {
struct can_filter dfilter; /* default/single filter */
struct can_filter *filter; /* pointer to filter(s) */
can_err_mask_t err_mask;
+ struct uniqframe __percpu *uniq;
};
/*
@@ -123,6 +129,15 @@ static void raw_rcv(struct sk_buff *oskb, void *data)
if (!ro->fd_frames && oskb->len != CAN_MTU)
return;
+ /* 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;
+ } else {
+ this_cpu_ptr(ro->uniq)->skb = oskb;
+ this_cpu_ptr(ro->uniq)->tstamp = oskb->tstamp;
+ }
+
/* clone the given skb to be able to enqueue it into the rcv queue */
skb = skb_clone(oskb, GFP_ATOMIC);
if (!skb)
@@ -297,6 +312,11 @@ static int raw_init(struct sock *sk)
ro->recv_own_msgs = 0;
ro->fd_frames = 0;
+ /* alloc_percpu provides zero'ed memory */
+ ro->uniq = alloc_percpu(struct uniqframe);
+ if (unlikely(!ro->uniq))
+ return -ENOMEM;
+
/* set notifier */
ro->notifier.notifier_call = raw_notifier;
@@ -339,6 +359,7 @@ static int raw_release(struct socket *sock)
ro->ifindex = 0;
ro->bound = 0;
ro->count = 0;
+ free_percpu(ro->uniq);
sock_orphan(sk);
sock->sk = NULL;