diff options
Diffstat (limited to 'Documentation/networking/segmentation-offloads.txt')
| -rw-r--r-- | Documentation/networking/segmentation-offloads.txt | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/Documentation/networking/segmentation-offloads.txt b/Documentation/networking/segmentation-offloads.txt index d47480b61ac6..aca542ec125c 100644 --- a/Documentation/networking/segmentation-offloads.txt +++ b/Documentation/networking/segmentation-offloads.txt @@ -20,8 +20,8 @@ TCP Segmentation Offload TCP segmentation allows a device to segment a single frame into multiple frames with a data payload size specified in skb_shinfo()->gso_size. -When TCP segmentation requested the bit for either SKB_GSO_TCP or -SKB_GSO_TCP6 should be set in skb_shinfo()->gso_type and +When TCP segmentation requested the bit for either SKB_GSO_TCPV4 or +SKB_GSO_TCPV6 should be set in skb_shinfo()->gso_type and skb_shinfo()->gso_size should be set to a non-zero value. TCP segmentation is dependent on support for the use of partial checksum @@ -153,8 +153,18 @@ To signal this, gso_size is set to the special value GSO_BY_FRAGS. Therefore, any code in the core networking stack must be aware of the possibility that gso_size will be GSO_BY_FRAGS and handle that case -appropriately. (For size checks, the skb_gso_validate_*_len family of -helpers do this automatically.) +appropriately. + +There are some helpers to make this easier: + + - skb_is_gso(skb) && skb_is_gso_sctp(skb) is the best way to see if + an skb is an SCTP GSO skb. + + - For size checks, the skb_gso_validate_*_len family of helpers correctly + considers GSO_BY_FRAGS. + + - For manipulating packets, skb_increase_gso_size and skb_decrease_gso_size + will check for GSO_BY_FRAGS and WARN if asked to manipulate these skbs. This also affects drivers with the NETIF_F_FRAGLIST & NETIF_F_GSO_SCTP bits set. Note also that NETIF_F_GSO_SCTP is included in NETIF_F_GSO_SOFTWARE. |