From: Maor Gottlieb <ma...@mellanox.com>

Add new packet type to skip kernel specific protocol handlers.

This is needed so device drivers can pass packets up to user space
(af_packet/tcpdump, etc..) without the need for them to go through
the whole kernel data path.

Signed-off-by: Maor Gottlieb <ma...@mellanox.com>
CC: David S. Miller <da...@davemloft.net>
CC: Patrick McHardy <ka...@trash.net>
CC: Eric Dumazet <eduma...@google.com>
Signed-off-by: Saeed Mahameed <sae...@mellanox.com>
---
 include/linux/skbuff.h         | 6 +++---
 include/uapi/linux/if_packet.h | 1 +
 net/core/dev.c                 | 4 ++++
 3 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index dc0fca7..359724e 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -694,14 +694,14 @@ struct sk_buff {
 
 /* if you move pkt_type around you also must adapt those constants */
 #ifdef __BIG_ENDIAN_BITFIELD
-#define PKT_TYPE_MAX   (7 << 5)
+#define PKT_TYPE_MAX   (8 << 5)
 #else
-#define PKT_TYPE_MAX   7
+#define PKT_TYPE_MAX   8
 #endif
 #define PKT_TYPE_OFFSET()      offsetof(struct sk_buff, __pkt_type_offset)
 
        __u8                    __pkt_type_offset[0];
-       __u8                    pkt_type:3;
+       __u8                    pkt_type:4;
        __u8                    pfmemalloc:1;
        __u8                    ignore_df:1;
        __u8                    nfctinfo:3;
diff --git a/include/uapi/linux/if_packet.h b/include/uapi/linux/if_packet.h
index 9e7edfd..93a9f13 100644
--- a/include/uapi/linux/if_packet.h
+++ b/include/uapi/linux/if_packet.h
@@ -29,6 +29,7 @@ struct sockaddr_ll {
 #define PACKET_LOOPBACK                5               /* MC/BRD frame looped 
back */
 #define PACKET_USER            6               /* To user space        */
 #define PACKET_KERNEL          7               /* To kernel space      */
+#define PACKET_OFFLOAD_KERNEL  8               /* Offload NET stack    */
 /* Unused, PACKET_FASTROUTE and PACKET_LOOPBACK are invisible to user space */
 #define PACKET_FASTROUTE       6               /* Fastrouted frame     */
 
diff --git a/net/core/dev.c b/net/core/dev.c
index d40593b..f300f1a 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4113,6 +4113,9 @@ another_round:
                pt_prev = ptype;
        }
 
+       if (unlikely(skb->pkt_type == PACKET_OFFLOAD_KERNEL))
+               goto done;
+
 skip_taps:
 #ifdef CONFIG_NET_INGRESS
        if (static_key_false(&ingress_needed)) {
@@ -4190,6 +4193,7 @@ ncls:
                                       &skb->dev->ptype_specific);
        }
 
+done:
        if (pt_prev) {
                if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
                        goto drop;
-- 
2.8.0

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