design for IPFS and go code

BitSwap.md

This allows nodes to keep track of history and avoid tampering.

type Ledger struct {
owner NodeId
partner NodeId
bytes_sent int
bytes_recv int
timestamp Timestamp
}

BitSwap Specification

// Additional state kept
type BitSwap struct {
ledgers map[NodeId]Ledger
// Ledgers known to this node, inc inactive
active map[NodeId]Peer
// currently open connections to other nodes
need_list []Multihash
// checksums of blocks this node needs
have_list []Multihash
// checksums of blocks this node has
}
type Peer struct {
nodeid NodeId
ledger Ledger
// Ledger between the node and this peer
last_seen Timestamp
// timestamp of last received message
want_list []Multihash
// checksums of all blocks wanted by peer
// includes blocks wanted by peer’s peers
}
// Protocol interface:
interface Peer {
open (nodeid :NodeId, ledger :Ledger);
send_want_list (want_list :WantList);
send_block (block :Block) -> (complete :Bool);
close (final :Bool);
}

Identify.md

type NodeId Multihash
type Multihash []byte
// self-describing cryptographic hash digest
type PublicKey []byte
type PrivateKey []byte
// self-describing keys
type Node struct {
NodeId NodeID
PubKey PublicKey
PriKey PrivateKey
}

S/Kademlia based IPFS identity generation:

difficulty = <integer parameter>
n = Node{}
do {
n.PubKey, n.PrivKey = PKI.genKeyPair()
n.NodeId = hash(n.PubKey)
p = count_preceding_zero_bits(hash(n.NodeId))
} while (p < difficulty)

Upon first connecting, peers exchange public keys, and check: hash(other.PublicKey) equals other.NodeId. If not, the connection is terminated.

so cool that, it uses three paramter just include []byte, it's the best design for me.

Routing.md

type IPFSRouting interface {
FindPeer(node NodeId)
// gets a particular peer’s network address
SetValue(key []bytes, value []bytes)
// stores a small metadata value in DHT
GetValue(key []bytes)
// retrieves small metadata value from DHT
ProvideValue(key Multihash)
// announces this node can serve a large value
FindValuePeers(key Multihash, min int)
// gets a number of peers serving a large value
}