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authorMiroslav Lichvar <mlichvar@redhat.com>2017-05-19 17:52:38 +0200
committerDavid S. Miller <davem@davemloft.net>2017-05-21 13:37:32 -0400
commitaad9c8c470f2a8321a99eb053630ce0e199558d6 (patch)
tree8b98ee6312da615961395f30ed0d650528d54fc7 /include/uapi/asm-generic
parent90b602f80397657429373ca009f98aec4dd3c553 (diff)
net: add new control message for incoming HW-timestamped packets
Add SOF_TIMESTAMPING_OPT_PKTINFO option to request a new control message for incoming packets with hardware timestamps. It contains the index of the real interface which received the packet and the length of the packet at layer 2. The index is useful with bonding, bridges and other interfaces, where IP_PKTINFO doesn't allow applications to determine which PHC made the timestamp. With the L2 length (and link speed) it is possible to transpose preamble timestamps to trailer timestamps, which are used in the NTP protocol. While this information could be provided by two new socket options independently from timestamping, it doesn't look like they would be very useful. With this option any performance impact is limited to hardware timestamping. Use dev_get_by_napi_id() to get the device and its index. On kernels with disabled CONFIG_NET_RX_BUSY_POLL or drivers not using NAPI, a zero index will be returned in the control message. CC: Richard Cochran <richardcochran@gmail.com> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/uapi/asm-generic')
-rw-r--r--include/uapi/asm-generic/socket.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
index 2b488565599d..a5f6e819fafd 100644
--- a/include/uapi/asm-generic/socket.h
+++ b/include/uapi/asm-generic/socket.h
@@ -100,4 +100,6 @@
#define SO_COOKIE 57
+#define SCM_TIMESTAMPING_PKTINFO 58
+
#endif /* __ASM_GENERIC_SOCKET_H */

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