README
¶
ethernet 
@startuml
title ethernet
class Frame {
+Destination net.HardwareAddr
+Source net.HardwareAddr
+VLAN []*VLAN
+EtherType EtherType
+Payload []byte
+MarshalBinary() []byte
+UnmarshalBinary([]byte)
+MarshalFCS() []byte
+UnmarshalFCS([]byte)
-read([]byte)
-length()
}
enum EtherType {
IPv4
ARP
IPv6
VLAN
}
enum Priority {
Background
BestEffort
ExcellentEffort
CriticalApplications
Video
Voice
InternetworkControl
NetworkControl
}
interface net.HardwareAddr {}
class VLAN {
+Priority
+DropEligible
+ID
+MarshalBinary() []byte
-read([]byte)
+UnmarshalBinary([]byte)
}
Frame *-- VLAN
@enduml
Documentation
¶
Overview ¶
Package ethernet implements marshaling and unmarshaling of IEEE 802.3 Ethernet II frames and IEEE 802.10 VLAN tags.
Index ¶
Constants ¶
const ( // VLANNone is a special VLAN ID which indicates that no VLAN is being // used in a Frame. In this case, the VLAN's other fields may be used // to indicate a Frame's priority VLANNone = 0x000 // VLANMax is a reserved VLAN ID which may indicate a wildcard in some // management system, but may not configured or transmitted in a // VLAN tag. VLANMax = 0xfff )
Variables ¶
var ( // Broadcast is a special hardware address which indicates a Frame should be // sent to every device on a given LAN segment. Broadcast = net.HardwareAddr{0xff, 0xff, 0xff, 0xff, 0xff, 0xff} // ErrInvalidFCS is returned when Frame.UnmarshalFCS detects an incorrect // Ethernet frame check sequence in a byte slice for a Frame. ErrInvalidFCS = errors.New("invalid frame check sequence") )
var ( // ErrInvalidVLAN is returned when a VLAN tag is invalid due to one of the // following reasons: // - Priority of greater than 7 is detected // - ID of greater than 4094 (0xffe) is detected ErrInvalidVLAN = errors.New("invalid VLAN") )
Functions ¶
This section is empty.
Types ¶
type EtherType ¶
type EtherType uint16
An EtherType is a value used to identify an upper layer protocol encapsulated in a Frame
type Frame ¶
type Frame struct {
// Destination specifies the destination hardware address for this Frame.
// If this address is set to Broadcast, the Frame will be sent to every
// device on a given LAN segment.
Destination net.HardwareAddr
// Source specifies the source hardware address for this Frame. Typically,
// this hardware address is the address of the network interface used to send
// this Frame.
Source net.HardwareAddr
// Vlan specifies one or more optional 802.1Q VLAN tags, which many or may
// not be present in a Frame. If no VLAN tags are present, this length of
// the slice will be 0.
VLAN []*VLAN
// EtherType is a value used to identify an upper layer protocol
// encapsulated in this Frame.
EtherType EtherType
// Payload is a variable length data payload encapsulated by this Frame
Payload []byte
}
A Frame is an IEEE 802.3 Ethernet II frame. A Frame contains information such as source and destination hardware addresses, zero or more optional 802.1Q VLAN tags, an EtherType, and payload data.
func (*Frame) MarshalBinary ¶
MarshalBinary allocates a byte slice and marshals a Frame into binary form.
If one or more VLANs are set and their IDs are too large (greater than 4094), or one or more VLANs' priority are too large (greater than 7), ErrInvalidVLAN is returned
func (*Frame) MarshalFCS ¶
MarshalFCS allocates a byte slice, marshals a Frame into binary form, and finally calculates and places a 4-byte IEEE CRC32 frame check sequence at the end of the slice
func (*Frame) UnmarshalBinary ¶
UnmarshalBinary unmarshals a byte slice into a Frame
If the byte slice does not contain enough data to unmarshal a valid Frame, io.ErrUnexpectedEOF is returned.
If one or more VLANs are detected and their IDs are too large (greater than 4094), ErrInvalidVLAN is returned
func (*Frame) UnmarshalFCS ¶
UnmarshalFCS computes the IEEE CRC32 frame check sequence of a Frame, verifies it against the checksum present in the byte slice, and finally, unmarshals a byte slice into a Frame
type Priority ¶
type Priority uint8
Priority is an IEEE P802.1p priority level. Priority can be any value from 0 to 7
It is important to note that priority 1 (PriorityBackground) actually has a lower priority than 0 (PriorityBestEffor). All other Priority constants indicate higher priority as the integer values increase
const ( PriorityBackground Priority = 1 PriorityBestEffort Priority = 0 PriorityExcellentEffort Priority = 2 PriorityCriticalApplications Priority = 3 PriorityVideo Priority = 4 PriorityVoice Priority = 5 PriorityInternetworkControl Priority = 6 PriorityNetworkControl Priority = 7 )
IEEE P802.1p recommended priority levels. Note that PriorityBackground has a lower prirority than PriorityBestEffor
type VLAN ¶
type VLAN struct {
// Priority specifies an IEEE 802.1p priority level.
Priority Priority
// DropEligible indicates if a Frame is eligible to be dropped in the
// presence of network congestion
DropEligible bool
// ID specifies the VLAN ID for a Frame. ID can be any value from 0 to
// 4094 (0x000 to 0xffe), allowing up to 4094 VLANs.
//
// If ID is 0 (0x000, VLANNone), no VLAN is specified, and the other fields
// simply indicate a Frame's priority
ID uint16
}
A VLAN is an IEEE 802.1Q Virtual LAN (VLAN) tag. A VLAN contains information regarding traffic priority and a VLAN identifier for a given Frame.
func (*VLAN) MarshalBinary ¶
MarshalBinary allocates a byte slice and marshals a VLAN into binary form.
If a VLAN ID is too large (greater than 4094), ErrInvalidVLAN is returned. If a VLAN priority is too large (greater than 7), ErrInvalidVLAN is returned.
func (*VLAN) UnmarshalBinary ¶
UnmarshalBinary unmarshals a byte slice into a VLAN
If the byte slice does not contain exactly 2 bytes of data, io.ErrUnexpectedEOF is returned
If a VLAN ID is too large (greater than 4094), ErrInvalidVLAN is returned.
Source Files
Directories
¶
| Path | Synopsis |
|---|---|
|
cmd
|
|
|
etherecho
Command etherecho broadcasts a message to all machines in the same network segment, and listens for other messages from other etherecho servers.
|
Command etherecho broadcasts a message to all machines in the same network segment, and listens for other messages from other etherecho servers. |