nl-pktloc-lookup - Lookup packet location definitions
nl-pktloc-lookup searches the packet location database for a matching entry. It
is used to resolve packet location aliases to their definition, i.e.
alignment, layer, offset, and mask.
- -h or --help
- Print help text to console and exit.
- -v or --version
- Print versioning information to console and exit.
- -l or --list
- List all packet location definitions.
- Prints the packet location definition in a special format
that is understood by iproute2's u32 selector parser. It will output a u32
selector which will compare the provided value with the value specified by
the packet location.
Please note that due to the limitation of u32, it is not possible to use
packet locations based on the link layer. nl-pktloc-lookup will print an
error message in this case.
selector=$(nl-pktloc-lookup --u32 22 tcp.sport)
tc filter add [...] u32 match $(selector) flowid 1:2
Thomas Graf is the original author and current maintainer of libnl and libnl
tools. Many people have contributed to it since.