socket

Documentation

Overview

Package socket implements AF_PACKET sockets / file descriptors (both for `afring` and plain `afpacket` modes). In addition, allocated sockets provide access to packet capture statistics for the underlying network interface during capture.

Index

• Constants
• type FileDescriptor
  • func New(iface *link.Link) (FileDescriptor, error)
  • func (sd FileDescriptor) Close() error
  • func (sd FileDescriptor) GetSocketStats() (ss TPacketStats, err error)
  • func (sd FileDescriptor) IsOpen() bool
  • func (sd FileDescriptor) SetSocketOptions(iface *link.Link, snapLen int, promisc bool) error
  • func (sd FileDescriptor) SetupRingBuffer(val unsafe.Pointer, vallen uintptr) error
• type MockFileDescriptor
  • func NewMock() (MockFileDescriptor, error)
  • func (m *MockFileDescriptor) Get() capture.Packet
  • func (m *MockFileDescriptor) GetSocketStats() (ss TPacketStats, err error)
  • func (m *MockFileDescriptor) GetSocketStatsNoReset() (ss TPacketStats, err error)
  • func (m *MockFileDescriptor) HasPackets() bool
  • func (m *MockFileDescriptor) IncrementPacketCount(delta uint64)
  • func (m *MockFileDescriptor) LastPoll() int64
  • func (m *MockFileDescriptor) Put(pkt capture.Packet)
  • func (m *MockFileDescriptor) ReleaseSemaphore() (errno unix.Errno)
  • func (m *MockFileDescriptor) SetNoRelease(enable bool) *MockFileDescriptor
• type TPacketStats

Constants

const (
	TPacketVersion = unix.TPACKET_V3 // TPacketVersion : The TPacket header version to use
)

Types

type FileDescriptor

type FileDescriptor int

FileDescriptor denotes a generic system level file descriptor (an int)

func New

func New(iface *link.Link) (FileDescriptor, error)

New instantiates a new file decriptor

func (FileDescriptor) Close

func (sd FileDescriptor) Close() error

Close closes the file descriptor

func (FileDescriptor) GetSocketStats

func (sd FileDescriptor) GetSocketStats() (ss TPacketStats, err error)

GetSocketStats returns (and resets) socket / traffic statistics

func (FileDescriptor) IsOpen

func (sd FileDescriptor) IsOpen() bool

IsOpen determines if the file descriptor is open / valid

func (FileDescriptor) SetSocketOptions

func (sd FileDescriptor) SetSocketOptions(iface *link.Link, snapLen int, promisc bool) error

SetSocketOptions sets several socket options on the underlying file descriptor required to perform AF_PACKET capture and retrieval of socket / traffic statistics

func (FileDescriptor) SetupRingBuffer

func (sd FileDescriptor) SetupRingBuffer(val unsafe.Pointer, vallen uintptr) error

SetupRingBuffer peforms a call via setsockopt() to prepare a mmmap'ed ring buffer

type MockFileDescriptor

type MockFileDescriptor struct {
	FileDescriptor
	// contains filtered or unexported fields
}

MockFileDescriptor denotes a mock file descriptor mimicking the behavior of an AF_PACKET socket by means of using a simple event file descriptor instead

func NewMock

func NewMock() (MockFileDescriptor, error)

NewMock instantiates a new mock file descriptor

func (*MockFileDescriptor) Get

func (m *MockFileDescriptor) Get() capture.Packet

Get fetches a single packets from the (buffered) mock file descriptor

func (*MockFileDescriptor) GetSocketStats

func (m *MockFileDescriptor) GetSocketStats() (ss TPacketStats, err error)

GetSocketStats returns (and resets) socket / traffic statistics

func (*MockFileDescriptor) GetSocketStatsNoReset

func (m *MockFileDescriptor) GetSocketStatsNoReset() (ss TPacketStats, err error)

GetSocketStatsNoReset returns socket / traffic statistics (without resetting the counters)

func (*MockFileDescriptor) HasPackets

func (m *MockFileDescriptor) HasPackets() bool

HasPackets returns if there are currently any packets in the mock buffer

func (*MockFileDescriptor) IncrementPacketCount

func (m *MockFileDescriptor) IncrementPacketCount(delta uint64)

IncrementPacketCount allows for simulation of packet / traffic statistics by means of manual counting (to be used during population of a mock data source)

func (*MockFileDescriptor) LastPoll

func (m *MockFileDescriptor) LastPoll() int64

LastPoll return the timestamp of the last poll on the FileDescriptor

func (*MockFileDescriptor) Put

func (m *MockFileDescriptor) Put(pkt capture.Packet)

Put sends a single packets via the (buffered) mock file descriptor

func (*MockFileDescriptor) ReleaseSemaphore

func (m *MockFileDescriptor) ReleaseSemaphore() (errno unix.Errno)

ReleaseSemaphore consumes from the event fd, releasing the semaphore and indicating that the next event can be sent

func (*MockFileDescriptor) SetNoRelease

func (m *MockFileDescriptor) SetNoRelease(enable bool) *MockFileDescriptor

SetNoRelease disables reading from the eventFD after data has been consumed (thereby not releasing the block which has to be handled elsewhere instead)

type TPacketStats

type TPacketStats struct {
	Packets      uint32
	Drops        uint32
	QueueFreezes uint32
}

TPacketStats denotes the V3 tpacket_stats structure, c.f. https://github.com/torvalds/linux/blob/master/include/uapi/linux/if_packet.h