package edgediscovery import ( "fmt" "net" "sync" "github.com/cloudflare/cloudflared/edgediscovery/allregions" "github.com/sirupsen/logrus" ) const ( subsystem = "edgediscovery" ) var errNoAddressesLeft = fmt.Errorf("There are no free edge addresses left") // Edge finds addresses on the Cloudflare edge and hands them out to connections. type Edge struct { regions *allregions.Regions sync.Mutex logger *logrus.Entry } // ------------------------------------ // Constructors // ------------------------------------ // ResolveEdge runs the initial discovery of the Cloudflare edge, finding Addrs that can be allocated // to connections. func ResolveEdge(l *logrus.Logger) (*Edge, error) { logger := l.WithField("subsystem", subsystem) regions, err := allregions.ResolveEdge(logger) if err != nil { return new(Edge), err } return &Edge{ logger: logger, regions: regions, }, nil } // StaticEdge creates a list of edge addresses from the list of hostnames. Mainly used for testing connectivity. func StaticEdge(l *logrus.Logger, hostnames []string) (*Edge, error) { logger := l.WithField("subsystem", subsystem) regions, err := allregions.StaticEdge(hostnames) if err != nil { return new(Edge), err } return &Edge{ logger: logger, regions: regions, }, nil } // MockEdge creates a Cloudflare Edge from arbitrary TCP addresses. Used for testing. func MockEdge(l *logrus.Logger, addrs []*net.TCPAddr) *Edge { logger := l.WithField("subsystem", subsystem) regions := allregions.NewNoResolve(addrs) return &Edge{ logger: logger, regions: regions, } } // ------------------------------------ // Methods // ------------------------------------ // GetAddrForRPC gives this connection an edge Addr. func (ed *Edge) GetAddrForRPC() (*net.TCPAddr, error) { ed.Lock() defer ed.Unlock() addr := ed.regions.GetAnyAddress() if addr == nil { return nil, errNoAddressesLeft } return addr, nil } // GetAddr gives this proxy connection an edge Addr. Prefer Addrs this connection has already used. func (ed *Edge) GetAddr(connID int) (*net.TCPAddr, error) { ed.Lock() defer ed.Unlock() logger := ed.logger.WithFields(logrus.Fields{ "connID": connID, "function": "GetAddr", }) // If this connection has already used an edge addr, return it. if addr := ed.regions.AddrUsedBy(connID); addr != nil { logger.Debug("Returning same address back to proxy connection") return addr, nil } // Otherwise, give it an unused one addr := ed.regions.GetUnusedAddr(nil, connID) if addr == nil { logger.Debug("No addresses left to give proxy connection") return nil, errNoAddressesLeft } logger.Debug("Giving connection its new address") return addr, nil } // GetDifferentAddr gives back the proxy connection's edge Addr and uses a new one. func (ed *Edge) GetDifferentAddr(connID int) (*net.TCPAddr, error) { ed.Lock() defer ed.Unlock() logger := ed.logger.WithFields(logrus.Fields{ "connID": connID, "function": "GetDifferentAddr", }) oldAddr := ed.regions.AddrUsedBy(connID) if oldAddr != nil { ed.regions.GiveBack(oldAddr) } addr := ed.regions.GetUnusedAddr(oldAddr, connID) if addr == nil { logger.Debug("No addresses left to give proxy connection") return nil, errNoAddressesLeft } logger.Debug("Giving connection its new address") return addr, nil } // AvailableAddrs returns how many unused addresses there are left. func (ed *Edge) AvailableAddrs() int { ed.Lock() defer ed.Unlock() return ed.regions.AvailableAddrs() } // GiveBack the address so that other connections can use it. // Returns true if the address is in this edge. func (ed *Edge) GiveBack(addr *net.TCPAddr) bool { ed.Lock() defer ed.Unlock() ed.logger.WithField("function", "GiveBack").Debug("Address now unused") return ed.regions.GiveBack(addr) }