package router import ( "errors" "sync" "time" "github.com/google/uuid" ) var ( // ErrRouteNotFound is returned when no route was found in the routing table ErrRouteNotFound = errors.New("route not found") // ErrDuplicateRoute is returned when the route already exists ErrDuplicateRoute = errors.New("duplicate route") ) // Table is an in memory routing table type Table struct { // routes stores service routes routes map[string]map[uint64]Route // watchers stores table watchers watchers map[string]*tableWatcher sync.RWMutex } // NewTable creates a new routing table and returns it func NewTable(opts ...Option) *Table { return &Table{ routes: make(map[string]map[uint64]Route), watchers: make(map[string]*tableWatcher), } } // Create creates new route in the routing table func (t *Table) Create(r Route) error { service := r.Service sum := r.Hash() t.Lock() defer t.Unlock() // check if there are any routes in the table for the route destination if _, ok := t.routes[service]; !ok { t.routes[service] = make(map[uint64]Route) t.routes[service][sum] = r go t.sendEvent(&Event{Type: Create, Timestamp: time.Now(), Route: r}) return nil } // add new route to the table for the route destination if _, ok := t.routes[service][sum]; !ok { t.routes[service][sum] = r go t.sendEvent(&Event{Type: Create, Timestamp: time.Now(), Route: r}) return nil } return ErrDuplicateRoute } // Delete deletes the route from the routing table func (t *Table) Delete(r Route) error { service := r.Service sum := r.Hash() t.Lock() defer t.Unlock() if _, ok := t.routes[service]; !ok { return ErrRouteNotFound } delete(t.routes[service], sum) go t.sendEvent(&Event{Type: Delete, Timestamp: time.Now(), Route: r}) return nil } // Update updates routing table with the new route func (t *Table) Update(r Route) error { service := r.Service sum := r.Hash() t.Lock() defer t.Unlock() // check if the route destination has any routes in the table if _, ok := t.routes[service]; !ok { t.routes[service] = make(map[uint64]Route) t.routes[service][sum] = r go t.sendEvent(&Event{Type: Create, Timestamp: time.Now(), Route: r}) return nil } t.routes[service][sum] = r go t.sendEvent(&Event{Type: Update, Timestamp: time.Now(), Route: r}) return nil } // List returns a list of all routes in the table func (t *Table) List() ([]Route, error) { t.RLock() defer t.RUnlock() var routes []Route for _, rmap := range t.routes { for _, route := range rmap { routes = append(routes, route) } } return routes, nil } // isMatch checks if the route matches given network and router func isMatch(route Route, network, router string) bool { if network == "*" || network == route.Network { if router == "*" || router == route.Gateway { return true } } return false } // findRoutes finds all the routes for given network and router and returns them func findRoutes(routes map[uint64]Route, network, router string) []Route { var results []Route for _, route := range routes { if isMatch(route, network, router) { results = append(results, route) } } return results } // Lookup queries routing table and returns all routes that match the lookup query func (t *Table) Lookup(q Query) ([]Route, error) { t.RLock() defer t.RUnlock() if q.Options().Service != "*" { if _, ok := t.routes[q.Options().Service]; !ok { return nil, ErrRouteNotFound } return findRoutes(t.routes[q.Options().Service], q.Options().Network, q.Options().Gateway), nil } var results []Route // search through all destinations for _, routes := range t.routes { results = append(results, findRoutes(routes, q.Options().Network, q.Options().Gateway)...) } return results, nil } // Watch returns routing table entry watcher func (t *Table) Watch(opts ...WatchOption) (Watcher, error) { // by default watch everything wopts := WatchOptions{ Service: "*", } for _, o := range opts { o(&wopts) } w := &tableWatcher{ opts: wopts, resChan: make(chan *Event, 10), done: make(chan struct{}), } t.Lock() t.watchers[uuid.New().String()] = w t.Unlock() return w, nil } // sendEvent sends events to all subscribed watchers func (t *Table) sendEvent(e *Event) { t.RLock() defer t.RUnlock() for _, w := range t.watchers { select { case w.resChan <- e: case <-w.done: } } } // String returns debug information func (t *Table) String() string { return "table" }