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;
         }