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128 lines
4.3 KiB
Go
128 lines
4.3 KiB
Go
// Package routing provides interfaces for peer routing and content routing in libp2p.
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package routing
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import (
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"context"
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"errors"
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ci "github.com/libp2p/go-libp2p-core/crypto"
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"github.com/libp2p/go-libp2p-core/peer"
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cid "github.com/ipfs/go-cid"
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)
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// ErrNotFound is returned when the router fails to find the requested record.
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var ErrNotFound = errors.New("routing: not found")
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// ErrNotSupported is returned when the router doesn't support the given record
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// type/operation.
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var ErrNotSupported = errors.New("routing: operation or key not supported")
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// ContentRouting is a value provider layer of indirection. It is used to find
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// information about who has what content.
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//
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// Content is identified by CID (content identifier), which encodes a hash
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// of the identified content in a future-proof manner.
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type ContentRouting interface {
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// Provide adds the given cid to the content routing system. If 'true' is
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// passed, it also announces it, otherwise it is just kept in the local
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// accounting of which objects are being provided.
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Provide(context.Context, cid.Cid, bool) error
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// Search for peers who are able to provide a given key
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//
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// When count is 0, this method will return an unbounded number of
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// results.
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FindProvidersAsync(context.Context, cid.Cid, int) <-chan peer.AddrInfo
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}
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// PeerRouting is a way to find address information about certain peers.
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// This can be implemented by a simple lookup table, a tracking server,
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// or even a DHT.
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type PeerRouting interface {
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// FindPeer searches for a peer with given ID, returns a peer.AddrInfo
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// with relevant addresses.
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FindPeer(context.Context, peer.ID) (peer.AddrInfo, error)
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}
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// ValueStore is a basic Put/Get interface.
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type ValueStore interface {
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// PutValue adds value corresponding to given Key.
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PutValue(context.Context, string, []byte, ...Option) error
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// GetValue searches for the value corresponding to given Key.
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GetValue(context.Context, string, ...Option) ([]byte, error)
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// SearchValue searches for better and better values from this value
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// store corresponding to the given Key. By default implementations must
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// stop the search after a good value is found. A 'good' value is a value
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// that would be returned from GetValue.
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//
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// Useful when you want a result *now* but still want to hear about
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// better/newer results.
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//
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// Implementations of this methods won't return ErrNotFound. When a value
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// couldn't be found, the channel will get closed without passing any results
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SearchValue(context.Context, string, ...Option) (<-chan []byte, error)
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}
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// Routing is the combination of different routing types supported by libp2p.
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// It can be satisfied by a single item (such as a DHT) or multiple different
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// pieces that are more optimized to each task.
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type Routing interface {
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ContentRouting
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PeerRouting
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ValueStore
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// Bootstrap allows callers to hint to the routing system to get into a
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// Boostrapped state and remain there. It is not a synchronous call.
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Bootstrap(context.Context) error
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// TODO expose io.Closer or plain-old Close error
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}
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// PubKeyFetcher is an interfaces that should be implemented by value stores
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// that can optimize retrieval of public keys.
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//
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// TODO(steb): Consider removing, see https://github.com/libp2p/go-libp2p-routing/issues/22.
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type PubKeyFetcher interface {
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// GetPublicKey returns the public key for the given peer.
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GetPublicKey(context.Context, peer.ID) (ci.PubKey, error)
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}
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// KeyForPublicKey returns the key used to retrieve public keys
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// from a value store.
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func KeyForPublicKey(id peer.ID) string {
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return "/pk/" + string(id)
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}
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// GetPublicKey retrieves the public key associated with the given peer ID from
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// the value store.
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//
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// If the ValueStore is also a PubKeyFetcher, this method will call GetPublicKey
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// (which may be better optimized) instead of GetValue.
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func GetPublicKey(r ValueStore, ctx context.Context, p peer.ID) (ci.PubKey, error) {
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switch k, err := p.ExtractPublicKey(); err {
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case peer.ErrNoPublicKey:
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// check the datastore
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case nil:
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return k, nil
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default:
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return nil, err
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}
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if dht, ok := r.(PubKeyFetcher); ok {
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// If we have a DHT as our routing system, use optimized fetcher
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return dht.GetPublicKey(ctx, p)
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}
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key := KeyForPublicKey(p)
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pkval, err := r.GetValue(ctx, key)
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if err != nil {
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return nil, err
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}
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// get PublicKey from node.Data
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return ci.UnmarshalPublicKey(pkval)
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}
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