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-rw-r--r--Documentation/networking/packet_mmap.txt9
1 files changed, 7 insertions, 2 deletions
diff --git a/Documentation/networking/packet_mmap.txt b/Documentation/networking/packet_mmap.txt
index 4288ffafba9f..723bf3d33a6e 100644
--- a/Documentation/networking/packet_mmap.txt
+++ b/Documentation/networking/packet_mmap.txt
@@ -517,8 +517,6 @@ where 'tpacket_version' can be TPACKET_V1 (default), TPACKET_V2, TPACKET_V3.
TPACKET_V1:
- Default if not otherwise specified by setsockopt(2)
- RX_RING, TX_RING available
- - VLAN metadata information available for packets
- (TP_STATUS_VLAN_VALID)
TPACKET_V1 --> TPACKET_V2:
- Made 64 bit clean due to unsigned long usage in TPACKET_V1
@@ -526,6 +524,13 @@ TPACKET_V1 --> TPACKET_V2:
userspace and the like
- Timestamp resolution in nanoseconds instead of microseconds
- RX_RING, TX_RING available
+ - VLAN metadata information available for packets
+ (TP_STATUS_VLAN_VALID, TP_STATUS_VLAN_TPID_VALID),
+ in the tpacket2_hdr structure:
+ - TP_STATUS_VLAN_VALID bit being set into the tp_status field indicates
+ that the tp_vlan_tci field has valid VLAN TCI value
+ - TP_STATUS_VLAN_TPID_VALID bit being set into the tp_status field
+ indicates that the tp_vlan_tpid field has valid VLAN TPID value
- How to switch to TPACKET_V2:
1. Replace struct tpacket_hdr by struct tpacket2_hdr
2. Query header len and save