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Diffstat (limited to 'Documentation/networking/segmentation-offloads.rst')
| -rw-r--r-- | Documentation/networking/segmentation-offloads.rst | 22 |
1 files changed, 14 insertions, 8 deletions
diff --git a/Documentation/networking/segmentation-offloads.rst b/Documentation/networking/segmentation-offloads.rst index 085e8fab03fd..72f69b22b28c 100644 --- a/Documentation/networking/segmentation-offloads.rst +++ b/Documentation/networking/segmentation-offloads.rst @@ -43,10 +43,19 @@ also point to the TCP header of the packet. For IPv4 segmentation we support one of two types in terms of the IP ID. The default behavior is to increment the IP ID with every segment. If the GSO type SKB_GSO_TCP_FIXEDID is specified then we will not increment the IP -ID and all segments will use the same IP ID. If a device has -NETIF_F_TSO_MANGLEID set then the IP ID can be ignored when performing TSO -and we will either increment the IP ID for all frames, or leave it at a -static value based on driver preference. +ID and all segments will use the same IP ID. + +For encapsulated packets, SKB_GSO_TCP_FIXEDID refers only to the outer header. +SKB_GSO_TCP_FIXEDID_INNER can be used to specify the same for the inner header. +Any combination of these two GSO types is allowed. + +If a device has NETIF_F_TSO_MANGLEID set then the IP ID can be ignored when +performing TSO and we will either increment the IP ID for all frames, or leave +it at a static value based on driver preference. For encapsulated packets, +NETIF_F_TSO_MANGLEID is relevant for both outer and inner headers, unless the +DF bit is not set on the outer header, in which case the device driver must +guarantee that the IP ID field is incremented in the outer header with every +segment. UDP Fragmentation Offload @@ -124,10 +133,7 @@ Generic Receive Offload Generic receive offload is the complement to GSO. Ideally any frame assembled by GRO should be segmented to create an identical sequence of frames using GSO, and any sequence of frames segmented by GSO should be -able to be reassembled back to the original by GRO. The only exception to -this is IPv4 ID in the case that the DF bit is set for a given IP header. -If the value of the IPv4 ID is not sequentially incrementing it will be -altered so that it is when a frame assembled via GRO is segmented via GSO. +able to be reassembled back to the original by GRO. Partial Generic Segmentation Offload |