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README
¶
vnet
A virtual network layer for pion.
Overview
Goals
- To make NAT traversal tests easy.
- To emulate packet impairment at application level for testing.
- To monitor packets at specified arbitrary interfaces.
Features
- Configurable virtual LAN and WAN
- Virtually hosted ICE servers
Virtual network components
Top View
......................................
: Virtual Network (vnet) :
: :
+-------+ * 1 +----+ +--------+ :
| :App |------------>|:Net|--o<-----|:Router | :
+-------+ +----+ | | :
+-----------+ * 1 +----+ | | :
|:STUNServer|-------->|:Net|--o<-----| | :
+-----------+ +----+ | | :
+-----------+ * 1 +----+ | | :
|:TURNServer|-------->|:Net|--o<-----| | :
+-----------+ +----+ [1] | | :
: 1 | | 1 <<has>> :
: +---<>| |<>----+ [2] :
: | +--------+ | :
To form | *| v 0..1 :
a subnet tree | o [3] +-----+ :
: | ^ |:NAT | :
: | | +-----+ :
: +-------+ :
......................................
Note:
o: NIC (Network Interface Controller)
[1]: Net implements NIC interface.
[2]: Root router has no NAT. All child routers have a NAT always.
[3]: Router implements NIC interface for accesses from the
parent router.
Net
Net provides 3 interfaces:
- Configuration API (direct)
- Network API via Net (equivalent to net.Xxx())
- Router access via NIC interface
(Pion module/app, ICE servers, etc.)
+-----------+
| :App |
+-----------+
* |
| <<uses>>
1 v
+---------+ 1 * +-----------+ 1 * +-----------+ 1 * +------+
..| :Router |----+------>o--| :Net |<>------|:Interface |<>------|:Addr |
+---------+ | NIC +-----------+ +-----------+ +------+
| <<interface>> (transport.Interface) (net.Addr)
|
| * +-----------+ 1 * +-----------+ 1 * +------+
+------>o--| :Router |<>------|:Interface |<>------|:Addr |
NIC +-----------+ +-----------+ +------+
<<interface>> (transport.Interface) (net.Addr)
The instance of
Netwill be the one passed around the project. Net class has public methods for configuration and for application use.
Implementation
Design Policy
- Each pion package should have config object which has
Net(of typetransport.Net) property.- Just like how we distribute
LoggerFactorythroughout the pion project.
- Just like how we distribute
- DNS => a simple dictionary (global)?
- Each Net has routing capability (a goroutine)
- Use interface provided net package as much as possible
- Routers are connected in a tree structure (no loop is allowed)
- To simplify routing
- Easy to control / monitor (stats, etc)
- Root router has no NAT (== Internet / WAN)
- Non-root router has a NAT always
- When a Net is instantiated, it will automatically add
lo0andeth0interface, andlo0will have one IP address, 127.0.0.1. (this is not used in pion/ice, however) - When a Net is added to a router, the router automatically assign an IP address for
eth0interface.- For simplicity
- User data won't fragment, but optionally drop chunk larger than MTU
- IPv6 is not supported
Basic steps for setting up virtual network
- Create a root router (WAN)
- Create child routers and add to its parent (forms a tree, don't create a loop!)
- Add instances of Net to each routers
- Call Stop(), or Stop(), on the top router, which propagates all other routers
Example: WAN with one endpoint (vnet)
import (
"net"
"github.com/pion/transport"
"github.com/pion/transport/vnet"
"github.com/pion/logging"
)
// Create WAN (a root router).
wan, err := vnet.NewRouter(&RouterConfig{
CIDR: "0.0.0.0/0",
LoggerFactory: logging.NewDefaultLoggerFactory(),
})
// Create a network.
// You can specify a static IP for the instance of Net to use. If not specified,
// router will assign an IP address that is contained in the router's CIDR.
nw := vnet.NewNet(&vnet.NetConfig{
StaticIP: "27.1.2.3",
})
// Add the network to the router.
// The router will assign an IP address to `nw`.
if err = wan.AddNet(nw); err != nil {
// handle error
}
// Start router.
// This will start internal goroutine to route packets.
// If you set child routers (using AddRouter), the call on the root router
// will start the rest of routers for you.
if err = wan.Start(); err != nil {
// handle error
}
//
// Your application runs here using `nw`.
//
// Stop the router.
// This will stop all internal Go routines in the router tree.
// (No need to call Stop() on child routers)
if err = wan.Stop(); err != nil {
// handle error
}
Example of how to pass around the instance of vnet.Net
The instance of vnet.Net wraps a subset of net package to enable operations
on the virtual network. Your project must be able to pass the instance to
all your routines that do network operation with net package. A typical way
is to use a config param to create your instances with the virtual network
instance (nw in the above example) like this:
type AgentConfig struct {
:
Net: transport.Net,
}
type Agent struct {
:
net: transport.Net,
}
func NetAgent(config *AgentConfig) *Agent {
if config.Net == nil {
config.Net = vnet.NewNet()
}
return &Agent {
:
net: config.Net,
}
}
// a.net is the instance of vnet.Net class
func (a *Agent) listenUDP(...) error {
conn, err := a.net.ListenPacket(udpString, ...)
if err != nil {
return nil, err
}
:
}
Compatibility and Support Status
net(built-in) |
vnet |
Note |
|---|---|---|
| net.Interfaces() | a.net.Interfaces() | |
| net.InterfaceByName() | a.net.InterfaceByName() | |
| net.ResolveUDPAddr() | a.net.ResolveUDPAddr() | |
| net.ListenPacket() | a.net.ListenPacket() | |
| net.ListenUDP() | a.net.ListenUDP() | ListenPacket() is recommended |
| net.Listen() | a.net.Listen() | TODO) |
| net.ListenTCP() | (not supported) | Listen() would be recommended |
| net.Dial() | a.net.Dial() | |
| net.DialUDP() | a.net.DialUDP() | |
| net.DialTCP() | (not supported) | |
| net.Interface | transport.Interface | |
| net.PacketConn | (use it as-is) | |
| net.UDPConn | transport.UDPConn | |
| net.TCPConn | transport.TCPConn | TODO: Use net.Conn in your code |
| net.Dialer | transport.Dialer | Use a.net.CreateDialer() to create it. The use of vnet.Dialer is currently experimental. |
a.netis an instance of Net class, and types are defined under the package namevnet
Most of other
interfacetypes in net package can be used as is.
Please post a github issue when other types/methods need to be added to vnet/vnet.Net.
TODO / Next Step
- Implement TCP (TCPConn, Listen)
- Support of IPv6
- Write a bunch of examples for building virtual networks.
- Add network impairment features (on Router)
- Introduce latency / jitter
- Packet filtering handler (allow selectively drop packets, etc.)
- Add statistics data retrieval
- Total number of packets forward by each router
- Total number of packet loss
- Total number of connection failure (TCP)
References
Documentation
¶
Overview ¶
Package vnet provides a virtual network layer for pion
Index ¶
- Constants
- type Chunk
- type ChunkFilter
- type DelayFilter
- type EndpointDependencyType
- type LossFilter
- type NATMode
- type NATType
- type NIC
- type Net
- func (v *Net) CreateDialer(d *net.Dialer) transport.Dialer
- func (v *Net) Dial(network string, address string) (net.Conn, error)
- func (v *Net) DialTCP(string, *net.TCPAddr, *net.TCPAddr) (transport.TCPConn, error)
- func (v *Net) DialUDP(network string, locAddr, remAddr *net.UDPAddr) (transport.UDPConn, error)
- func (v *Net) InterfaceByIndex(index int) (*transport.Interface, error)
- func (v *Net) InterfaceByName(ifName string) (*transport.Interface, error)
- func (v *Net) Interfaces() ([]*transport.Interface, error)
- func (v *Net) ListenPacket(network string, address string) (net.PacketConn, error)
- func (v *Net) ListenTCP(string, *net.TCPAddr) (transport.TCPListener, error)
- func (v *Net) ListenUDP(network string, locAddr *net.UDPAddr) (transport.UDPConn, error)
- func (v *Net) ResolveIPAddr(_, address string) (*net.IPAddr, error)
- func (v *Net) ResolveTCPAddr(network, address string) (*net.TCPAddr, error)
- func (v *Net) ResolveUDPAddr(network, address string) (*net.UDPAddr, error)
- type NetConfig
- type Router
- func (r *Router) AddChildRouter(router *Router) error
- func (r *Router) AddChunkFilter(filter ChunkFilter)
- func (r *Router) AddHost(hostName string, ipAddr string) error
- func (r *Router) AddNet(nic NIC) error
- func (r *Router) AddRouter(router *Router) error
- func (r *Router) Start() error
- func (r *Router) Stop() error
- type RouterConfig
- type TBFOption
- type TokenBucketFilter
- type UDPConn
- func (c *UDPConn) Close() error
- func (c *UDPConn) LocalAddr() net.Addr
- func (c *UDPConn) Read(b []byte) (int, error)
- func (c *UDPConn) ReadFrom(p []byte) (n int, addr net.Addr, err error)
- func (c *UDPConn) ReadFromUDP(b []byte) (int, *net.UDPAddr, error)
- func (c *UDPConn) ReadMsgUDP([]byte, []byte) (n, oobn, flags int, addr *net.UDPAddr, err error)
- func (c *UDPConn) RemoteAddr() net.Addr
- func (c *UDPConn) SetDeadline(t time.Time) error
- func (c *UDPConn) SetReadBuffer(int) error
- func (c *UDPConn) SetReadDeadline(t time.Time) error
- func (c *UDPConn) SetWriteBuffer(int) error
- func (c *UDPConn) SetWriteDeadline(time.Time) error
- func (c *UDPConn) Write(b []byte) (int, error)
- func (c *UDPConn) WriteMsgUDP([]byte, []byte, *net.UDPAddr) (n, oobn int, err error)
- func (c *UDPConn) WriteTo(p []byte, addr net.Addr) (n int, err error)
- func (c *UDPConn) WriteToUDP(b []byte, addr *net.UDPAddr) (int, error)
- type UDPProxy
Constants ¶
const ( // Bit is a single bit Bit = 1 // KBit is a kilobit KBit = 1000 * Bit // MBit is a Megabit MBit = 1000 * KBit )
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Chunk ¶
type Chunk interface {
SourceAddr() net.Addr
DestinationAddr() net.Addr
UserData() []byte
Tag() string
Clone() Chunk
Network() string // returns "udp" or "tcp"
String() string
// contains filtered or unexported methods
}
Chunk represents a packet passed around in the vnet
type ChunkFilter ¶
ChunkFilter is a handler users can add to filter chunks. If the filter returns false, the packet will be dropped.
type DelayFilter ¶
type DelayFilter struct {
NIC
// contains filtered or unexported fields
}
DelayFilter delays outgoing packets by the given delay. Run must be called before any packets will be forwarded.
func NewDelayFilter ¶
func NewDelayFilter(nic NIC, delay time.Duration) (*DelayFilter, error)
NewDelayFilter creates a new DelayFilter with the given nic and delay.
func (*DelayFilter) Run ¶
func (f *DelayFilter) Run(ctx context.Context)
Run starts forwarding of packets. Packets will be forwarded if they spent >delay time in the internal queue. Must be called before any packet will be forwarded.
type EndpointDependencyType ¶
type EndpointDependencyType uint8
EndpointDependencyType defines a type of behavioral dependendency on the remote endpoint's IP address or port number. This is used for the two kinds of behaviors:
- Port mapping behavior
- Filtering behavior
See: https://tools.ietf.org/html/rfc4787
const ( // EndpointIndependent means the behavior is independent of the endpoint's address or port EndpointIndependent EndpointDependencyType = iota // EndpointAddrDependent means the behavior is dependent on the endpoint's address EndpointAddrDependent // EndpointAddrPortDependent means the behavior is dependent on the endpoint's address and port EndpointAddrPortDependent )
type LossFilter ¶
type LossFilter struct {
NIC
// contains filtered or unexported fields
}
LossFilter is a wrapper around NICs, that drops some of the packets passed to onInboundChunk
func NewLossFilter ¶
func NewLossFilter(nic NIC, chance int) (*LossFilter, error)
NewLossFilter creates a new LossFilter that drops every packet with a probability of chance/100. Every packet that is not dropped is passed on to the given NIC.
type NATMode ¶
type NATMode uint8
NATMode defines basic behavior of the NAT
const ( // NATModeNormal means the NAT behaves as a standard NAPT (RFC 2663). NATModeNormal NATMode = iota // NATModeNAT1To1 exhibits 1:1 DNAT where the external IP address is statically mapped to // a specific local IP address with port number is preserved always between them. // When this mode is selected, MappingBehavior, FilteringBehavior, PortPreservation and // MappingLifeTime of NATType are ignored. NATModeNAT1To1 )
type NATType ¶
type NATType struct {
Mode NATMode
MappingBehavior EndpointDependencyType
FilteringBehavior EndpointDependencyType
Hairpinning bool // Not implemented yet
PortPreservation bool // Not implemented yet
MappingLifeTime time.Duration
}
NATType has a set of parameters that define the behavior of NAT.
type NIC ¶
type NIC interface {
// contains filtered or unexported methods
}
NIC is a network interface controller that interfaces Router
type Net ¶
type Net struct {
// contains filtered or unexported fields
}
Net represents a local network stack equivalent to a set of layers from NIC up to the transport (UDP / TCP) layer.
func NewNet ¶
NewNet creates an instance of a virtual network.
By design, it always have lo0 and eth0 interfaces. The lo0 has the address 127.0.0.1 assigned by default. IP address for eth0 will be assigned when this Net is added to a router.
func (*Net) CreateDialer ¶
CreateDialer creates an instance of vnet.Dialer
func (*Net) InterfaceByIndex ¶
InterfaceByIndex returns the interface specified by index.
On Solaris, it returns one of the logical network interfaces sharing the logical data link; for more precision use InterfaceByName.
func (*Net) InterfaceByName ¶
InterfaceByName returns the interface specified by name.
func (*Net) Interfaces ¶
Interfaces returns a list of the system's network interfaces.
func (*Net) ListenPacket ¶
ListenPacket announces on the local network address.
func (*Net) ResolveIPAddr ¶
ResolveIPAddr returns an address of IP end point.
func (*Net) ResolveTCPAddr ¶
ResolveTCPAddr returns an address of TCP end point.
type NetConfig ¶
type NetConfig struct {
// StaticIPs is an array of static IP addresses to be assigned for this Net.
// If no static IP address is given, the router will automatically assign
// an IP address.
StaticIPs []string
// StaticIP is deprecated. Use StaticIPs.
StaticIP string
}
NetConfig is a bag of configuration parameters passed to NewNet().
type Router ¶
type Router struct {
// contains filtered or unexported fields
}
Router ...
func (*Router) AddChildRouter ¶
AddChildRouter is like AddRouter, but does not add the child routers NIC to the parent. This has to be done manually by calling AddNet, which allows to use a wrapper around the subrouters NIC. AddNet MUST be called before AddChildRouter.
func (*Router) AddChunkFilter ¶
func (r *Router) AddChunkFilter(filter ChunkFilter)
AddChunkFilter adds a filter for chunks traversing this router. You may add more than one filter. The filters are called in the order of this method call. If a chunk is dropped by a filter, subsequent filter will not receive the chunk.
func (*Router) AddHost ¶
AddHost adds a mapping of hostname and an IP address to the local resolver.
type RouterConfig ¶
type RouterConfig struct {
// Name of router. If not specified, a unique name will be assigned.
Name string
// CIDR notation, like "192.0.2.0/24"
CIDR string
// StaticIPs is an array of static IP addresses to be assigned for this router.
// If no static IP address is given, the router will automatically assign
// an IP address.
// This will be ignored if this router is the root.
StaticIPs []string
// StaticIP is deprecated. Use StaticIPs.
StaticIP string
// Internal queue size
QueueSize int
// Effective only when this router has a parent router
NATType *NATType
// Minimum Delay
MinDelay time.Duration
// Max Jitter
MaxJitter time.Duration
// Logger factory
LoggerFactory logging.LoggerFactory
}
RouterConfig ...
type TBFOption ¶
type TBFOption func(*TokenBucketFilter) TBFOption
TBFOption is the option type to configure a TokenBucketFilter
func TBFMaxBurst ¶
TBFMaxBurst sets the bucket size of the token bucket filter. This is the maximum size that can instantly leave the filter, if the bucket is full.
func TBFQueueSizeInBytes ¶
TBFQueueSizeInBytes sets the max number of bytes waiting in the queue. Can only be set in constructor before using the TBF.
type TokenBucketFilter ¶
type TokenBucketFilter struct {
NIC
// contains filtered or unexported fields
}
TokenBucketFilter implements a token bucket rate limit algorithm.
func NewTokenBucketFilter ¶
func NewTokenBucketFilter(n NIC, opts ...TBFOption) (*TokenBucketFilter, error)
NewTokenBucketFilter creates and starts a new TokenBucketFilter
func (*TokenBucketFilter) Close ¶
func (t *TokenBucketFilter) Close() error
Close closes and stops the token bucket filter queue
func (*TokenBucketFilter) Set ¶
func (t *TokenBucketFilter) Set(opts ...TBFOption) (previous TBFOption)
Set updates a setting on the token bucket filter
type UDPConn ¶
type UDPConn struct {
// contains filtered or unexported fields
}
UDPConn is the implementation of the Conn and PacketConn interfaces for UDP network connections. compatible with net.PacketConn and net.Conn
func (*UDPConn) Close ¶
Close closes the connection. Any blocked ReadFrom or WriteTo operations will be unblocked and return errors.
func (*UDPConn) Read ¶
Read reads data from the connection. Read can be made to time out and return an Error with Timeout() == true after a fixed time limit; see SetDeadline and SetReadDeadline.
func (*UDPConn) ReadFrom ¶
ReadFrom reads a packet from the connection, copying the payload into p. It returns the number of bytes copied into p and the return address that was on the packet. It returns the number of bytes read (0 <= n <= len(p)) and any error encountered. Callers should always process the n > 0 bytes returned before considering the error err. ReadFrom can be made to time out and return an Error with Timeout() == true after a fixed time limit; see SetDeadline and SetReadDeadline.
func (*UDPConn) ReadFromUDP ¶
ReadFromUDP acts like ReadFrom but returns a UDPAddr.
func (*UDPConn) ReadMsgUDP ¶
ReadMsgUDP reads a message from c, copying the payload into b and the associated out-of-band data into oob. It returns the number of bytes copied into b, the number of bytes copied into oob, the flags that were set on the message and the source address of the message.
The packages golang.org/x/net/ipv4 and golang.org/x/net/ipv6 can be used to manipulate IP-level socket options in oob.
func (*UDPConn) RemoteAddr ¶
RemoteAddr returns the remote network address.
func (*UDPConn) SetDeadline ¶
SetDeadline sets the read and write deadlines associated with the connection. It is equivalent to calling both SetReadDeadline and SetWriteDeadline.
A deadline is an absolute time after which I/O operations fail with a timeout (see type Error) instead of blocking. The deadline applies to all future and pending I/O, not just the immediately following call to ReadFrom or WriteTo. After a deadline has been exceeded, the connection can be refreshed by setting a deadline in the future.
An idle timeout can be implemented by repeatedly extending the deadline after successful ReadFrom or WriteTo calls.
A zero value for t means I/O operations will not time out.
func (*UDPConn) SetReadBuffer ¶
SetReadBuffer sets the size of the operating system's receive buffer associated with the connection.
func (*UDPConn) SetReadDeadline ¶
SetReadDeadline sets the deadline for future ReadFrom calls and any currently-blocked ReadFrom call. A zero value for t means ReadFrom will not time out.
func (*UDPConn) SetWriteBuffer ¶
SetWriteBuffer sets the size of the operating system's transmit buffer associated with the connection.
func (*UDPConn) SetWriteDeadline ¶
SetWriteDeadline sets the deadline for future WriteTo calls and any currently-blocked WriteTo call. Even if write times out, it may return n > 0, indicating that some of the data was successfully written. A zero value for t means WriteTo will not time out.
func (*UDPConn) Write ¶
Write writes data to the connection. Write can be made to time out and return an Error with Timeout() == true after a fixed time limit; see SetDeadline and SetWriteDeadline.
func (*UDPConn) WriteMsgUDP ¶
WriteMsgUDP writes a message to addr via c if c isn't connected, or to c's remote address if c is connected (in which case addr must be nil). The payload is copied from b and the associated out-of-band data is copied from oob. It returns the number of payload and out-of-band bytes written.
The packages golang.org/x/net/ipv4 and golang.org/x/net/ipv6 can be used to manipulate IP-level socket options in oob.
type UDPProxy ¶
type UDPProxy struct {
// contains filtered or unexported fields
}
UDPProxy is a proxy between real server(net.UDPConn) and vnet.UDPConn.
High level design:
..............................................
: Virtual Network (vnet) :
: :
+-------+ * 1 +----+ +--------+ :
| :App |------------>|:Net|--o<-----|:Router | .............................
+-------+ +----+ | | : UDPProxy :
: | | +----+ +---------+ +---------+ +--------+
: | |--->o--|:Net|-->o-| vnet. |-->o-| net. |--->-| :Real |
: | | +----+ | UDPConn | | UDPConn | | Server |
: | | : +---------+ +---------+ +--------+
: | | ............................:
: +--------+ :
...............................................
func NewProxy ¶
NewProxy create a proxy, the router for this proxy belongs/bind to. If need to proxy for please create a new proxy for each router. For all addresses we proxy, we will create a vnet.Net in this router and proxy all packets.
Source Files