kubernetes/pkg/proxy/util/nfacct/nfacct_linux.go

const MaxLength …

const cmdNew …

const cmdGet …

const attrName …

const attrPackets …

const attrBytes …

type runner …

// New returns a new Interface. If the netfilter_nfacct subsystem is
// not available in the kernel it will return error.
func New() (Interface, error) { … }

// newInternal returns a new Interface with the given handler.
func newInternal(hndlr handler) (Interface, error) { … }

// Ensure is part of the interface.
func (r *runner) Ensure(name string) error { … }

// Add is part of the interface.
func (r *runner) Add(name string) error { … }

// Get is part of the interface.
func (r *runner) Get(name string) (*Counter, error) { … }

// List is part of the interface.
func (r *runner) List() ([]*Counter, error) { … }

var ErrObjectNotFound …

var ErrObjectAlreadyExists …

var ErrNameExceedsMaxLength …

var ErrEmptyName …

var ErrUnexpected …

var ErrNotSupported …

func handleError(err error) error { … }

// decode function processes a byte stream, requiring the 'strict' parameter to be true in production and
// false only for testing purposes. If in strict mode and any of the relevant attributes (name, packets, or bytes)
// have not been processed, an error is returned indicating a failure to decode the byte stream.
//
// Parse the netlink message as per the documentation outlined in:
// https://docs.kernel.org/userspace-api/netlink/intro.html
//
// Message Components:
//   - netfilter generic message [4 bytes]
//     struct nfgenmsg (definition: https://github.com/torvalds/linux/blob/v6.7/include/uapi/linux/netfilter/nfnetlink.h#L32-L38)
//   - attributes [variable-sized, must align to 4 bytes from the start of attribute]
//     struct nlattr (definition: https://github.com/torvalds/linux/blob/v6.7/include/uapi/linux/netlink.h#L220-L232)
//
// Attribute Components:
//   - length [2 bytes]
//     length includes bytes for defining the length itself, bytes for defining the type,
//     and the actual bytes of data without any padding.
//   - type [2 bytes]
//   - data [variable-sized]
//   - padding [optional]
//
// Example. Counter{Name: "dummy-metric", Packets: 123, Bytes: 54321} in netlink message:
//
//	struct nfgenmsg{
//	    __u8  nfgen_family: AF_NETLINK
//	    __u8    version:    nl.NFNETLINK_V0
//	    __be16  res_id:     nl.NFNETLINK_V0
//	}
//
//	struct nlattr{
//	    __u16 nla_len:      13
//	    __u16 nla_type:     NFACCT_NAME
//	    char data:          dummy-metric\0
//	}
//
//	(padding:)
//	    data:               \0\0\0
//
//	struct nlattr{
//	    __u16 nla_len:      12
//	    __u16 nla_type:     NFACCT_PKTS
//	    __u64: data:        123
//	}
//
//	struct nlattr{
//	    __u16 nla_len:      12
//	    __u16 nla_type:     NFACCT_BYTES
//	    __u64: data:        54321
//	}
func decode(msg []byte, strict bool) (*Counter, error) { … }