tracker/middleware/clientapproval/clientapproval.go

107 lines
2.8 KiB
Go

// Package clientapproval implements a Hook that fails an Announce based on a
// whitelist or blacklist of BitTorrent client IDs.
package clientapproval
import (
"context"
"errors"
"fmt"
"gopkg.in/yaml.v2"
"github.com/chihaya/chihaya/bittorrent"
"github.com/chihaya/chihaya/middleware"
)
// Name is the name by which this middleware is registered with Chihaya.
const Name = "client approval"
func init() {
middleware.RegisterDriver(Name, driver{})
}
var _ middleware.Driver = driver{}
type driver struct{}
func (d driver) NewHook(optionBytes []byte) (middleware.Hook, error) {
var cfg Config
err := yaml.Unmarshal(optionBytes, &cfg)
if err != nil {
return nil, fmt.Errorf("invalid options for middleware %s: %s", Name, err)
}
return NewHook(cfg)
}
// ErrClientUnapproved is the error returned when a client's PeerID is invalid.
var ErrClientUnapproved = bittorrent.ClientError("unapproved client")
// Config represents all the values required by this middleware to validate
// peers based on their BitTorrent client ID.
type Config struct {
Whitelist []string `yaml:"whitelist"`
Blacklist []string `yaml:"blacklist"`
}
type hook struct {
approved map[bittorrent.ClientID]struct{}
unapproved map[bittorrent.ClientID]struct{}
}
// NewHook returns an instance of the client approval middleware.
func NewHook(cfg Config) (middleware.Hook, error) {
h := &hook{
approved: make(map[bittorrent.ClientID]struct{}),
unapproved: make(map[bittorrent.ClientID]struct{}),
}
if len(cfg.Whitelist) > 0 && len(cfg.Blacklist) > 0 {
return nil, fmt.Errorf("using both whitelist and blacklist is invalid")
}
for _, cidString := range cfg.Whitelist {
cidBytes := []byte(cidString)
if len(cidBytes) != 6 {
return nil, errors.New("client ID " + cidString + " must be 6 bytes")
}
var cid bittorrent.ClientID
copy(cid[:], cidBytes)
h.approved[cid] = struct{}{}
}
for _, cidString := range cfg.Blacklist {
cidBytes := []byte(cidString)
if len(cidBytes) != 6 {
return nil, errors.New("client ID " + cidString + " must be 6 bytes")
}
var cid bittorrent.ClientID
copy(cid[:], cidBytes)
h.unapproved[cid] = struct{}{}
}
return h, nil
}
func (h *hook) HandleAnnounce(ctx context.Context, req *bittorrent.AnnounceRequest, resp *bittorrent.AnnounceResponse) (context.Context, error) {
clientID := bittorrent.NewClientID(req.Peer.ID)
if len(h.approved) > 0 {
if _, found := h.approved[clientID]; !found {
return ctx, ErrClientUnapproved
}
}
if len(h.unapproved) > 0 {
if _, found := h.unapproved[clientID]; found {
return ctx, ErrClientUnapproved
}
}
return ctx, nil
}
func (h *hook) HandleScrape(ctx context.Context, req *bittorrent.ScrapeRequest, resp *bittorrent.ScrapeResponse) (context.Context, error) {
// Scrapes don't require any protection.
return ctx, nil
}