can: fix multiple delivery of a single CAN frame for overlapping CAN filters

[cascardo/linux.git] / net / can / raw.c

diff --git a/net/can/raw.c b/net/can/raw.c
index 00c13ef..0c8d537 100644 (file)
--- 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;
 };
 
 /*
@@ -95,8 +101,8 @@ struct raw_sock {
  */
 static inline unsigned int *raw_flags(struct sk_buff *skb)
 {
-       BUILD_BUG_ON(sizeof(skb->cb) <= (sizeof(struct sockaddr_can) +
-                                        sizeof(unsigned int)));
+       sock_skb_cb_check_size(sizeof(struct sockaddr_can) +
+                              sizeof(unsigned int));
 
        /* return pointer after struct sockaddr_can */
        return (unsigned int *)(&((struct sockaddr_can *)skb->cb)[1]);
@@ -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)
@@ -135,7 +150,7 @@ static void raw_rcv(struct sk_buff *oskb, void *data)
         *  containing the interface index.
         */
 
-       BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct sockaddr_can));
+       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;
@@ -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;
@@ -658,8 +679,7 @@ static int raw_getsockopt(struct socket *sock, int level, int optname,
        return 0;
 }
 
-static int raw_sendmsg(struct kiocb *iocb, struct socket *sock,
-                      struct msghdr *msg, size_t size)
+static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
 {
        struct sock *sk = sock->sk;
        struct raw_sock *ro = raw_sk(sk);
@@ -728,8 +748,8 @@ send_failed:
        return err;
 }
 
-static int raw_recvmsg(struct kiocb *iocb, struct socket *sock,
-                      struct msghdr *msg, size_t size, int flags)
+static int raw_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
+                      int flags)
 {
        struct sock *sk = sock->sk;
        struct sk_buff *skb;