Skb event

Full skb collector events will be constructed with the following. Non-reported or invalid fields are automatically hidden.

VLAN hardware acceleration

In the Linux kernel the VLAN data can be part of the metadata instead of inside the packet (aka. "VLAN hardware acceleration"). This section displays this.

When not accelerated, the VLAN information is shown as part of the packet.

vlan_accel (ethertype {etype name} ({etype hex}) vlan {id} p {prio} [DEI])

Metadata & dataref

Those two sections report metadata and reference counting from the socket buffer itself.

skb [{csum} hash {skb hash} data_len {skb data lenght} priority {skb priority}
    {flags} fclone {fast clone count} users {user count} dataref {skb refcount}]
  • csum information, the format is slightly different depending on the checksum status (none, unnecessary, partial or complete).
  • flags are a combination of nohdr and cloned.

Generic segmentation offload (GSO)

Generic Segmentation Offload information linked to an skb (see skb_shared_info).

gso [type {GSO type} flags {GSO flags} frags {nr of GSO frags}
    segs {nr of GSO segs} size {GSO size}]
  • GSO type, see SKBFL_* in the Linux kernel include/linux/skbuff.h.
  • GSO flags, see SKB_GSO_* in the Linux kernel include/linux/skbuff.h.