Rift VM

Motivations

"Internet of Things"

Mesh protocols

P2P Applications

Goals

• Generalize IoT around P2P principles
• Provide a programming model which enables truly location-transparent applications
• Democratize access to networked services

Network design

The Internet we wanted

• Completely decentralized information network
• Communication is transparent to sender/receiver, but opaque to handler
• Bandwidth is limited by physical connectivity
• Isolated networks are possible and common
• Peer-to-peer sharing is the norm

The Internet we got

• Hierarchical information network
• Communication hops go through gateways
• Bandwidth is limited by private companies
• Isolated networks are possible but uncommon
• Peer-to-peer sharing is done through the cloud

Client-server model

• Clients consume services
• Clients must know where a service exists
  • IP address, hostname, etc
• Clients must acknowledge the limitations of the network
• Clients must accept the authenticity of the service

Client-server model (cont.)

• Servers provide services to clients
• Servers must be accessible to clients
  • DNS, CDN, etc
• Servers must acknowledge the limitations of the network
• Servers must prove their authenticity to clients
  • SSL

Client-server model (cont.)

• Something here about centralized services being horrible for the Internet

"Cloud" architecture

• Typically favors thin clients
• Fault-tolerant storage
• High-availability services
• Convenience in accessibility

"Cloud" architecture (cont.)

• Verbose, overly-connected clients
  • RPC, REST, HATEOAS, etc
• Replication of potentially sensitive data
• Use of DNS and CDNs to distribute services geographically
• Everything accessible everywhere

Rift architecture

• Inherently peer-to-peer
  • No single peer is outwardly distinct from any other
• Each peer may offer services to any other available peer
• Each peer may consume visible services of any other available peer
• Peers choose the visibility of their services
  • This even applies to globally-distributable services

Rift architecture (cont.)

• Services are immutable
  • Addressable by hash
• Services are remotely defined, but typically are locally executable
  • RPC is still used for "invisible" service dependencies such as database access
• Services must be signed and accepted by each consuming peer

Rift architecture (cont.)

• Network connectivity exists over multiple transports
  • 802.11s, Bluetooth, ZigBee, Unix sockets, etc
• Location transparency
  • Multiple peers may exist on the same physical device
• Service availability is physically and temporally defined

VM design

VM architecture

Exchange

Imports

Exports

Interpreter

Decoder

Encoder

Environment

Exchange subsystem

• Manages all code imports and exports
• Responsible for service visibility
• Verifies imports
• Signs exports
• Interfaces with other exchanges
  • Network, IPC, filesystem, native, etc

Serialization subsystem

• Encodes imported bytecodes
• Decodes exported bytecodes
• Computes service content hashes

Environment subsystem

• Manages VM state and memory
• Responsible for intraprocess subroutine visibility
• Routes subroutine dispatch requests
• Uses immutable, stack-based temporal bindings
• Interfaces directly with the interpreter to provide subroutine dispatch and variable dereference

Interpreter

• Register-based interpreter (stackless)
  • Heavily influenced by the Lua 5 VM
• Single-threaded with an I/O event loop
• Supports first-class continuations
• Uses a small amount of wide instructions
  • 13 core instructions, with up to 5 operands

Implementation constraints

• Implemented in Go
  • Platform independence, small memory footprint, C compatibility
• Indirect memory management
  • Uses the host runtime for allocation and collection
• First-class continuation support is limited to intraprocess
• Network exchange implement using WiFi
  • Multicast for service visibility and unicast for service consumption

Future

What's next?

• Bootstrap VM
• OpenPDS implementation
• Bluetooth LE exchange
• ZigBee exchange
• Native library exchange
• Better-integrated Android target
• iOS target
• Rift compiler?

Questions?