| 1 | package relay |
| 2 | |
| 3 | import ( |
| 4 | "encoding/binary" |
| 5 | "errors" |
| 6 | "fmt" |
| 7 | "math/rand/v2" |
| 8 | "net" |
| 9 | "sort" |
| 10 | "strconv" |
| 11 | "sync" |
| 12 | "time" |
| 13 | |
| 14 | "github.com/pion/logging" |
| 15 | "github.com/pion/stun/v3" |
| 16 | "github.com/pion/turn/v4" |
| 17 | ) |
| 18 | |
| 19 | // Realm is the TURN realm every credential is minted and verified under. |
| 20 | const Realm = "carlos" |
| 21 | |
| 22 | // pendingLife is how long a socket or an admission may sit unclaimed |
| 23 | // before tick reclaims it. Both are consumed within one request in the |
| 24 | // normal path; this only catches an allocation that failed after pion had |
| 25 | // already asked us for a socket. |
| 26 | const pendingLife = 30 * time.Second |
| 27 | |
| 28 | // authMemory is how long the last parsed username for a typed source is |
| 29 | // kept once that source has no allocation, so a client that authenticates |
| 30 | // and never allocates cannot grow the map without bound. |
| 31 | const authMemory = 10 * time.Minute |
| 32 | |
| 33 | const ( |
| 34 | // maxRefusalIdentities and maxLoggedRefusals bound the two maps an |
| 35 | // unauthenticated client can otherwise grow: pion calls AuthHandler |
| 36 | // with the raw username before it checks MESSAGE-INTEGRITY, so every |
| 37 | // counter keyed on something the caller chose is remote memory. Only |
| 38 | // identities in the authority record get their own row; everything |
| 39 | // else shares the zero identity, and these caps are the backstop. |
| 40 | maxRefusalIdentities = 4096 |
| 41 | maxLoggedRefusals = 4096 |
| 42 | |
| 43 | // refusalLogEvery is how often one identity's one refusal reason may |
| 44 | // put a line in the log. |
| 45 | refusalLogEvery = time.Minute |
| 46 | |
| 47 | // minLastAuthEntries is the floor under Limits.BoxLive*2 for how many |
| 48 | // typed sources may hold a remembered username at once. |
| 49 | minLastAuthEntries = 256 |
| 50 | ) |
| 51 | |
| 52 | var errTCPAllocUnsupported = errors.New("relay: TCP relay allocations are not supported") |
| 53 | |
| 54 | // ServerConfig is everything the relay needs from its process: where to |
| 55 | // listen, what to advertise, and the four live views (masters, authority, |
| 56 | // lease, limits) it reads on every request. |
| 57 | type ServerConfig struct { |
| 58 | Region string |
| 59 | RelayIP net.IP // the EIP advertised to clients |
| 60 | UDP, TCP string // listen addresses, e.g. ":3478"; empty disables |
| 61 | MinPort, MaxPort uint16 // 49152, 65535 |
| 62 | DenyCIDRs []*net.IPNet // from CARLOS_RELAY_DENY_CIDRS, on top of the built-in private ranges |
| 63 | ExtraAllow []*net.IPNet // peer ranges allowed despite the built-in list; empty in production |
| 64 | Masters func() *Masters |
| 65 | Authority func() *Authority |
| 66 | Lease func(now time.Time) bool |
| 67 | Limits Limits |
| 68 | Now func() time.Time |
| 69 | Log func(string, ...any) |
| 70 | |
| 71 | // Meter is the byte meter (Task 7); nil disables metering. It is an |
| 72 | // interface so this file does not depend on the meter's shape. |
| 73 | Meter interface { |
| 74 | Add(id Identity, in, out, rejected int64) |
| 75 | } |
| 76 | } |
| 77 | |
| 78 | // Server is the relay: a pion TURN server whose every socket we own, so |
| 79 | // that an allocation can be ended, attributed and bounded from outside |
| 80 | // pion, which exposes no way to do any of it. |
| 81 | type Server struct { |
| 82 | cfg ServerConfig |
| 83 | now func() time.Time |
| 84 | log func(string, ...any) |
| 85 | |
| 86 | adm *Admission |
| 87 | box *Bucket |
| 88 | ports *portSet |
| 89 | deny []*net.IPNet |
| 90 | allow []*net.IPNet |
| 91 | local []net.IP // our listeners' own addresses, when not wildcard |
| 92 | maxLastAuth int |
| 93 | |
| 94 | turn *turn.Server |
| 95 | udp net.PacketConn |
| 96 | tcp net.Listener |
| 97 | listeners []string |
| 98 | |
| 99 | mu sync.Mutex |
| 100 | seq int64 |
| 101 | pending map[int]pendingConn // relay port -> socket awaiting OnAllocationCreated |
| 102 | lastAuth map[string]authRec // typed source -> the username it last authenticated with |
| 103 | admits map[string]admitRec // typed source -> an admission not yet owned by an allocation |
| 104 | bound map[string]*Binding // typed source -> the identity it is bound to |
| 105 | allocs map[string]*allocEntry // typed source -> its live allocation |
| 106 | owners map[*relayConn]*allocEntry // socket -> what closing it must undo |
| 107 | byPort map[int]*relayConn // relay port -> its socket, however far the allocation got |
| 108 | refusals map[Identity]map[string]int |
| 109 | logged map[logKey]time.Time |
| 110 | shedding map[Identity]bool |
| 111 | } |
| 112 | |
| 113 | type logKey struct { |
| 114 | id Identity |
| 115 | reason string |
| 116 | } |
| 117 | |
| 118 | type allocEntry struct { |
| 119 | conn *relayConn |
| 120 | id Identity |
| 121 | key string // the typed source this allocation was created for |
| 122 | seq int64 |
| 123 | timer *time.Timer |
| 124 | flow *flow |
| 125 | } |
| 126 | |
| 127 | type pendingConn struct { |
| 128 | conn *relayConn |
| 129 | flow *flow |
| 130 | at time.Time |
| 131 | } |
| 132 | |
| 133 | // flow is one allocation's peer-to-client accounting. pion's allocation |
| 134 | // reads a peer packet and then either forwards it to the client or drops |
| 135 | // it for want of a permission, both on the allocation's own goroutine, so |
| 136 | // a packet that is still unforwarded when the next one arrives (or when |
| 137 | // the socket closes) is a packet that was dropped. That is what spec §3 |
| 138 | // counts as `rejected`, and it is never charged to a budget. |
| 139 | type flow struct { |
| 140 | mu sync.Mutex |
| 141 | awaiting int64 // size of the peer packet read and not yet forwarded |
| 142 | } |
| 143 | |
| 144 | // read records a peer packet and returns the bytes of the previous one if |
| 145 | // it was never forwarded. |
| 146 | func (f *flow) read(n int) int64 { |
| 147 | f.mu.Lock() |
| 148 | defer f.mu.Unlock() |
| 149 | dropped := f.awaiting |
| 150 | f.awaiting = int64(n) |
| 151 | return dropped |
| 152 | } |
| 153 | |
| 154 | // forwarded clears the packet the listener has just written to the client. |
| 155 | func (f *flow) forwarded() { |
| 156 | f.mu.Lock() |
| 157 | f.awaiting = 0 |
| 158 | f.mu.Unlock() |
| 159 | } |
| 160 | |
| 161 | // flush is the last packet's verdict when the socket closes. |
| 162 | func (f *flow) flush() int64 { |
| 163 | f.mu.Lock() |
| 164 | defer f.mu.Unlock() |
| 165 | dropped := f.awaiting |
| 166 | f.awaiting = 0 |
| 167 | return dropped |
| 168 | } |
| 169 | |
| 170 | // readCounter is the relay socket's peer-ingress leg. It sits under |
| 171 | // relayConn so that relayConn keeps counting only what it forwards. |
| 172 | type readCounter struct { |
| 173 | net.PacketConn |
| 174 | f *flow |
| 175 | onDrop func(int64) |
| 176 | } |
| 177 | |
| 178 | func (r *readCounter) ReadFrom(p []byte) (int, net.Addr, error) { |
| 179 | n, addr, err := r.PacketConn.ReadFrom(p) |
| 180 | if n > 0 { |
| 181 | if dropped := r.f.read(n); dropped > 0 && r.onDrop != nil { |
| 182 | r.onDrop(dropped) |
| 183 | } |
| 184 | } |
| 185 | return n, addr, err |
| 186 | } |
| 187 | |
| 188 | type authRec struct { |
| 189 | u Username |
| 190 | at time.Time |
| 191 | } |
| 192 | |
| 193 | type admitRec struct { |
| 194 | id Identity |
| 195 | at time.Time |
| 196 | } |
| 197 | |
| 198 | // builtinDeny is the peer policy every relay carries whatever the operator |
| 199 | // configures: loopback, link-local (the IMDS address included), RFC 1918, |
| 200 | // unique-local and carrier-grade NAT space; "this network" (0.0.0.0/8, which |
| 201 | // Linux delivers to the local host, not only the unspecified address), the |
| 202 | // IETF protocol-assignment block (192.0.0.0/24) and the benchmarking range |
| 203 | // (198.18.0.0/15), none of which is a public peer (discussion #220). |
| 204 | // |
| 205 | // IPv6 forms that carry an IPv4 address — NAT64 (64:ff9b::/96) and 6to4 |
| 206 | // (2002::/16) — are not listed: they are judged by the address they embed |
| 207 | // (see embeddedV4), so a NAT64 gateway cannot be used to reach 10.0.0.1 and |
| 208 | // a public address behind either one still works. |
| 209 | var builtinDeny = mustCIDRs( |
| 210 | "127.0.0.0/8", "::1/128", |
| 211 | "169.254.0.0/16", "fe80::/10", |
| 212 | "10.0.0.0/8", "172.16.0.0/12", "192.168.0.0/16", |
| 213 | "fc00::/7", "100.64.0.0/10", |
| 214 | "0.0.0.0/8", "192.0.0.0/24", "198.18.0.0/15", |
| 215 | ) |
| 216 | |
| 217 | // Prefixes whose addresses embed an IPv4 address: the NAT64 well-known |
| 218 | // prefix carries it in the last 32 bits (RFC 6052), 6to4 in bits 16-47 |
| 219 | // (RFC 3056). |
| 220 | var ( |
| 221 | nat64Prefix = mustCIDRs("64:ff9b::/96")[0] |
| 222 | sixToFour = mustCIDRs("2002::/16")[0] |
| 223 | ) |
| 224 | |
| 225 | // embeddedV4 returns the IPv4 address a NAT64 or 6to4 peer stands for, or |
| 226 | // nil for any other address. An IPv4-mapped address (::ffff:a.b.c.d) needs |
| 227 | // no help: net.IPNet.Contains already matches it against the IPv4 ranges. |
| 228 | func embeddedV4(ip net.IP) net.IP { |
| 229 | ip16 := ip.To16() |
| 230 | if ip16 == nil || ip.To4() != nil { |
| 231 | return nil |
| 232 | } |
| 233 | switch { |
| 234 | case nat64Prefix.Contains(ip16): |
| 235 | return net.IPv4(ip16[12], ip16[13], ip16[14], ip16[15]) |
| 236 | case sixToFour.Contains(ip16): |
| 237 | return net.IPv4(ip16[2], ip16[3], ip16[4], ip16[5]) |
| 238 | } |
| 239 | return nil |
| 240 | } |
| 241 | |
| 242 | func mustCIDRs(ss ...string) []*net.IPNet { |
| 243 | out := make([]*net.IPNet, 0, len(ss)) |
| 244 | for _, s := range ss { |
| 245 | _, n, err := net.ParseCIDR(s) |
| 246 | if err != nil { |
| 247 | panic("relay: bad built-in CIDR " + s + ": " + err.Error()) |
| 248 | } |
| 249 | out = append(out, n) |
| 250 | } |
| 251 | return out |
| 252 | } |
| 253 | |
| 254 | func NewServer(cfg ServerConfig) (*Server, error) { |
| 255 | if cfg.Now == nil { |
| 256 | cfg.Now = time.Now |
| 257 | } |
| 258 | if cfg.Log == nil { |
| 259 | cfg.Log = func(string, ...any) {} |
| 260 | } |
| 261 | if cfg.MinPort == 0 { |
| 262 | cfg.MinPort = 49152 |
| 263 | } |
| 264 | if cfg.MaxPort == 0 { |
| 265 | cfg.MaxPort = 65535 |
| 266 | } |
| 267 | switch { |
| 268 | case cfg.RelayIP == nil: |
| 269 | return nil, errors.New("relay: RelayIP is required") |
| 270 | case cfg.MinPort > cfg.MaxPort: |
| 271 | return nil, fmt.Errorf("relay: port range %d-%d is empty", cfg.MinPort, cfg.MaxPort) |
| 272 | case cfg.Masters == nil || cfg.Authority == nil || cfg.Lease == nil: |
| 273 | return nil, errors.New("relay: Masters, Authority and Lease are required") |
| 274 | case cfg.UDP == "" && cfg.TCP == "": |
| 275 | return nil, errors.New("relay: no listener configured") |
| 276 | } |
| 277 | |
| 278 | maxLastAuth := cfg.Limits.BoxLive * 2 |
| 279 | if maxLastAuth < minLastAuthEntries { |
| 280 | maxLastAuth = minLastAuthEntries |
| 281 | } |
| 282 | s := &Server{ |
| 283 | cfg: cfg, |
| 284 | now: cfg.Now, |
| 285 | log: cfg.Log, |
| 286 | adm: NewAdmission(cfg.Limits, cfg.Now), |
| 287 | box: NewBucket(cfg.Limits.BoxBitsPerSec, cfg.Now), |
| 288 | ports: &portSet{m: map[int]bool{}}, |
| 289 | deny: append(append([]*net.IPNet{}, builtinDeny...), cfg.DenyCIDRs...), |
| 290 | allow: append([]*net.IPNet{}, cfg.ExtraAllow...), |
| 291 | maxLastAuth: maxLastAuth, |
| 292 | pending: map[int]pendingConn{}, |
| 293 | lastAuth: map[string]authRec{}, |
| 294 | admits: map[string]admitRec{}, |
| 295 | bound: map[string]*Binding{}, |
| 296 | allocs: map[string]*allocEntry{}, |
| 297 | owners: map[*relayConn]*allocEntry{}, |
| 298 | byPort: map[int]*relayConn{}, |
| 299 | refusals: map[Identity]map[string]int{}, |
| 300 | logged: map[logKey]time.Time{}, |
| 301 | shedding: map[Identity]bool{}, |
| 302 | } |
| 303 | |
| 304 | var packets []turn.PacketConnConfig |
| 305 | var listeners []turn.ListenerConfig |
| 306 | if cfg.UDP != "" { |
| 307 | pc, err := net.ListenPacket("udp", cfg.UDP) |
| 308 | if err != nil { |
| 309 | return nil, fmt.Errorf("relay: listen udp %s: %w", cfg.UDP, err) |
| 310 | } |
| 311 | s.udp = pc |
| 312 | s.noteLocal(pc.LocalAddr()) |
| 313 | s.listeners = append(s.listeners, "udp:"+portOf(pc.LocalAddr())) |
| 314 | packets = append(packets, turn.PacketConnConfig{ |
| 315 | PacketConn: &listenerConn{PacketConn: pc, s: s}, |
| 316 | RelayAddressGenerator: s, |
| 317 | PermissionHandler: s.permit, |
| 318 | }) |
| 319 | } |
| 320 | if cfg.TCP != "" { |
| 321 | l, err := net.Listen("tcp", cfg.TCP) |
| 322 | if err != nil { |
| 323 | if s.udp != nil { |
| 324 | s.udp.Close() |
| 325 | } |
| 326 | return nil, fmt.Errorf("relay: listen tcp %s: %w", cfg.TCP, err) |
| 327 | } |
| 328 | s.tcp = l |
| 329 | s.noteLocal(l.Addr()) |
| 330 | s.listeners = append(s.listeners, "tcp:"+portOf(l.Addr())) |
| 331 | listeners = append(listeners, turn.ListenerConfig{ |
| 332 | Listener: &countingListener{Listener: l, s: s}, |
| 333 | RelayAddressGenerator: s, |
| 334 | PermissionHandler: s.permit, |
| 335 | }) |
| 336 | } |
| 337 | |
| 338 | ts, err := turn.NewServer(turn.ServerConfig{ |
| 339 | Realm: Realm, |
| 340 | AuthHandler: s.auth, |
| 341 | QuotaHandler: s.quota, |
| 342 | EventHandler: turn.EventHandler{OnAllocationCreated: s.created}, |
| 343 | PacketConnConfigs: packets, |
| 344 | ListenerConfigs: listeners, |
| 345 | LoggerFactory: logging.NewDefaultLoggerFactory(), |
| 346 | }) |
| 347 | if err != nil { |
| 348 | if s.udp != nil { |
| 349 | s.udp.Close() |
| 350 | } |
| 351 | if s.tcp != nil { |
| 352 | s.tcp.Close() |
| 353 | } |
| 354 | return nil, fmt.Errorf("relay: pion server: %w", err) |
| 355 | } |
| 356 | s.turn = ts |
| 357 | return s, nil |
| 358 | } |
| 359 | |
| 360 | func (s *Server) noteLocal(a net.Addr) { |
| 361 | var ip net.IP |
| 362 | switch v := a.(type) { |
| 363 | case *net.UDPAddr: |
| 364 | ip = v.IP |
| 365 | case *net.TCPAddr: |
| 366 | ip = v.IP |
| 367 | } |
| 368 | if ip != nil && !ip.IsUnspecified() { |
| 369 | s.local = append(s.local, ip) |
| 370 | } |
| 371 | } |
| 372 | |
| 373 | func portOf(a net.Addr) string { |
| 374 | switch v := a.(type) { |
| 375 | case *net.UDPAddr: |
| 376 | return strconv.Itoa(v.Port) |
| 377 | case *net.TCPAddr: |
| 378 | return strconv.Itoa(v.Port) |
| 379 | } |
| 380 | _, p, err := net.SplitHostPort(a.String()) |
| 381 | if err != nil { |
| 382 | return a.String() |
| 383 | } |
| 384 | return p |
| 385 | } |
| 386 | |
| 387 | // Listeners names the transports that are up, e.g. ["udp:3478","tcp:3478"], |
| 388 | // for the heartbeat. |
| 389 | func (s *Server) Listeners() []string { return append([]string{}, s.listeners...) } |
| 390 | |
| 391 | // UDPAddr is the UDP listener's bound address, or nil if UDP is disabled. |
| 392 | func (s *Server) UDPAddr() net.Addr { |
| 393 | if s.udp == nil { |
| 394 | return nil |
| 395 | } |
| 396 | return s.udp.LocalAddr() |
| 397 | } |
| 398 | |
| 399 | // Live is the number of allocations the relay is carrying. |
| 400 | func (s *Server) Live() int { |
| 401 | s.mu.Lock() |
| 402 | defer s.mu.Unlock() |
| 403 | return len(s.allocs) |
| 404 | } |
| 405 | |
| 406 | // LiveByIdentity is Live broken down per app, for the meter's `allocs` |
| 407 | // gauge (spec §3, "Metering"). The Meter the server holds is narrowed to |
| 408 | // Add, deliberately — the server counts bytes as it forwards them and knows |
| 409 | // nothing about sample boundaries — so the gauge is the serve loop's job to |
| 410 | // set, and this is where it reads it from. |
| 411 | func (s *Server) LiveByIdentity() map[Identity]int { |
| 412 | s.mu.Lock() |
| 413 | defer s.mu.Unlock() |
| 414 | out := make(map[Identity]int, len(s.allocs)) |
| 415 | for _, e := range s.allocs { |
| 416 | out[e.id]++ |
| 417 | } |
| 418 | return out |
| 419 | } |
| 420 | |
| 421 | // Seed replays metered bytes into the rolling-hour windows, so a restart |
| 422 | // resumes its budgets from the metrics objects it wrote. |
| 423 | func (s *Server) Seed(id Identity, at time.Time, n int64) { s.adm.Seed(id, at, n) } |
| 424 | |
| 425 | // Close ends every allocation and stops listening. |
| 426 | func (s *Server) Close() error { |
| 427 | s.EndAll("server closing") |
| 428 | s.mu.Lock() |
| 429 | pending := make([]*relayConn, 0, len(s.pending)) |
| 430 | for _, p := range s.pending { |
| 431 | pending = append(pending, p.conn) |
| 432 | } |
| 433 | s.mu.Unlock() |
| 434 | for _, c := range pending { |
| 435 | c.Close() |
| 436 | } |
| 437 | if s.turn == nil { |
| 438 | return nil |
| 439 | } |
| 440 | return s.turn.Close() |
| 441 | } |
| 442 | |
| 443 | // EndAll ends every allocation: a lease lapse, or shutdown. |
| 444 | func (s *Server) EndAll(reason string) { |
| 445 | s.EndWhere(func(*Binding) bool { return true }, reason) |
| 446 | } |
| 447 | |
| 448 | // EndWhere ends every allocation whose binding matches: a disable, an |
| 449 | // incarnation change, this region leaving an app's list, a byte budget, a |
| 450 | // retired master. The predicate is called on a copy of the binding, off |
| 451 | // the server's lock. |
| 452 | func (s *Server) EndWhere(match func(*Binding) bool, reason string) { |
| 453 | type candidate struct { |
| 454 | conn *relayConn |
| 455 | b Binding |
| 456 | } |
| 457 | s.mu.Lock() |
| 458 | cands := make([]candidate, 0, len(s.allocs)) |
| 459 | for _, e := range s.allocs { |
| 460 | cands = append(cands, candidate{conn: e.conn, b: *e.conn.b}) |
| 461 | } |
| 462 | s.mu.Unlock() |
| 463 | |
| 464 | n := 0 |
| 465 | for _, c := range cands { |
| 466 | b := c.b |
| 467 | if match(&b) { |
| 468 | c.conn.Close() |
| 469 | n++ |
| 470 | } |
| 471 | } |
| 472 | if n > 0 { |
| 473 | s.log("relay: ended %d allocation(s): %s", n, reason) |
| 474 | } |
| 475 | } |
| 476 | |
| 477 | // ShedOldest ends the n oldest allocations, for memory pressure. |
| 478 | func (s *Server) ShedOldest(n int) { |
| 479 | if n <= 0 { |
| 480 | return |
| 481 | } |
| 482 | s.mu.Lock() |
| 483 | entries := make([]*allocEntry, 0, len(s.allocs)) |
| 484 | for _, e := range s.allocs { |
| 485 | entries = append(entries, e) |
| 486 | } |
| 487 | s.mu.Unlock() |
| 488 | sort.Slice(entries, func(i, j int) bool { return entries[i].seq < entries[j].seq }) |
| 489 | if n > len(entries) { |
| 490 | n = len(entries) |
| 491 | } |
| 492 | for _, e := range entries[:n] { |
| 493 | e.conn.Close() |
| 494 | } |
| 495 | if n > 0 { |
| 496 | s.log("relay: shed %d oldest allocation(s)", n) |
| 497 | } |
| 498 | } |
| 499 | |
| 500 | // tick is the sweep: it ends allocations whose credential has expired |
| 501 | // (belt for the per-allocation timers), whose master has retired, whose app |
| 502 | // or account is over budget, and every allocation at all if the serving |
| 503 | // lease has lapsed. It also reclaims sockets and admissions that a failed |
| 504 | // allocation left behind. |
| 505 | func (s *Server) tick() { |
| 506 | now := s.now() |
| 507 | masters := s.cfg.Masters() |
| 508 | leaseDead := !s.cfg.Lease(now) |
| 509 | |
| 510 | type victim struct { |
| 511 | conn *relayConn |
| 512 | reason string |
| 513 | } |
| 514 | var victims []victim |
| 515 | var stale []*relayConn |
| 516 | |
| 517 | // A masters file that failed to reload leaves masters nil; that is a |
| 518 | // reason to keep serving on the keys we have, not to end anything. |
| 519 | retired := func(kid string) bool { |
| 520 | if masters == nil || kid == "" { |
| 521 | return false |
| 522 | } |
| 523 | _, ok := masters.Lookup(kid, now) |
| 524 | return !ok |
| 525 | } |
| 526 | |
| 527 | s.mu.Lock() |
| 528 | for _, e := range s.allocs { |
| 529 | b := e.conn.b |
| 530 | switch { |
| 531 | case leaseDead: |
| 532 | victims = append(victims, victim{e.conn, "serving lease lapsed"}) |
| 533 | case !b.Expiry.IsZero() && !b.Expiry.After(now): |
| 534 | victims = append(victims, victim{e.conn, "credential expired"}) |
| 535 | case retired(b.Kid): |
| 536 | victims = append(victims, victim{e.conn, "master " + b.Kid + " retired"}) |
| 537 | case s.adm.OverBudget(e.id, now): |
| 538 | victims = append(victims, victim{e.conn, "byte budget"}) |
| 539 | } |
| 540 | } |
| 541 | for port, p := range s.pending { |
| 542 | if now.Sub(p.at) > pendingLife { |
| 543 | delete(s.pending, port) |
| 544 | stale = append(stale, p.conn) |
| 545 | } |
| 546 | } |
| 547 | var lapsed []Identity |
| 548 | for key, a := range s.admits { |
| 549 | if now.Sub(a.at) > pendingLife { |
| 550 | delete(s.admits, key) |
| 551 | lapsed = append(lapsed, a.id) |
| 552 | } |
| 553 | } |
| 554 | for key, a := range s.lastAuth { |
| 555 | if _, live := s.allocs[key]; !live && now.Sub(a.at) > authMemory { |
| 556 | delete(s.lastAuth, key) |
| 557 | } |
| 558 | } |
| 559 | // Refusal counters live only for apps the authority still names; the |
| 560 | // zero identity is the shared bucket for everything else and stays. |
| 561 | for id := range s.refusals { |
| 562 | if id == (Identity{}) { |
| 563 | continue |
| 564 | } |
| 565 | if _, ok := s.cfg.Authority().Lookup(id.Account, id.App); !ok { |
| 566 | delete(s.refusals, id) |
| 567 | } |
| 568 | } |
| 569 | for k, at := range s.logged { |
| 570 | if now.Sub(at) >= refusalLogEvery { |
| 571 | delete(s.logged, k) |
| 572 | } |
| 573 | } |
| 574 | s.mu.Unlock() |
| 575 | |
| 576 | for _, id := range lapsed { |
| 577 | s.adm.Release(id) |
| 578 | } |
| 579 | for _, c := range stale { |
| 580 | c.Close() |
| 581 | } |
| 582 | for _, v := range victims { |
| 583 | s.log("relay: ending allocation for %s/%s: %s", v.conn.b.ID.Account, v.conn.b.ID.App, v.reason) |
| 584 | v.conn.Close() |
| 585 | } |
| 586 | } |
| 587 | |
| 588 | // --- turn.RelayAddressGenerator ------------------------------------------ |
| 589 | |
| 590 | func (s *Server) Validate() error { |
| 591 | if s.cfg.RelayIP == nil { |
| 592 | return errors.New("relay: RelayIP is required") |
| 593 | } |
| 594 | if s.cfg.MinPort > s.cfg.MaxPort { |
| 595 | return fmt.Errorf("relay: port range %d-%d is empty", s.cfg.MinPort, s.cfg.MaxPort) |
| 596 | } |
| 597 | return nil |
| 598 | } |
| 599 | |
| 600 | // AllocatePacketConn binds one allocation's relay socket in the configured |
| 601 | // port range and hands pion our wrapper for it: the wrapper is how the |
| 602 | // allocation is ended, metered and bounded. The advertised address is the |
| 603 | // EIP, which is not an address on the box, so the socket itself binds the |
| 604 | // wildcard. |
| 605 | func (s *Server) AllocatePacketConn(network string, requestedPort int) (net.PacketConn, net.Addr, error) { |
| 606 | if network == "" { |
| 607 | network = "udp4" |
| 608 | } |
| 609 | lo, hi := int(s.cfg.MinPort), int(s.cfg.MaxPort) |
| 610 | span := hi - lo + 1 |
| 611 | tries := span |
| 612 | if tries > 64 { |
| 613 | tries = 64 |
| 614 | } |
| 615 | ports := make([]int, 0, tries+1) |
| 616 | if requestedPort >= lo && requestedPort <= hi { |
| 617 | ports = append(ports, requestedPort) |
| 618 | } |
| 619 | start := rand.IntN(span) |
| 620 | for i := 0; i < tries; i++ { |
| 621 | ports = append(ports, lo+(start+i)%span) |
| 622 | } |
| 623 | |
| 624 | for _, port := range ports { |
| 625 | if s.ports.has(port) { |
| 626 | continue |
| 627 | } |
| 628 | pc, err := net.ListenPacket(network, net.JoinHostPort("", strconv.Itoa(port))) |
| 629 | if err != nil { |
| 630 | continue |
| 631 | } |
| 632 | bucket := NewBucket(s.cfg.Limits.AllocBitsPerSec, s.now) |
| 633 | f := &flow{} |
| 634 | var c *relayConn |
| 635 | // The socket counts peer ingress under the wrapper, so a peer |
| 636 | // packet pion drops for want of a permission is still seen. |
| 637 | counted := &readCounter{PacketConn: pc, f: f, onDrop: func(n int64) { s.countRejected(c.b.ID, n) }} |
| 638 | c = newRelayConn(counted, &Binding{}, s.cfg.RelayIP, s.ports, bucket, s.box, |
| 639 | s.countIn, s.countGated, func(rc *relayConn) { s.release(port, rc) }) |
| 640 | s.ports.add(port) |
| 641 | s.mu.Lock() |
| 642 | s.pending[port] = pendingConn{conn: c, flow: f, at: s.now()} |
| 643 | s.byPort[port] = c |
| 644 | s.mu.Unlock() |
| 645 | return c, &net.UDPAddr{IP: s.cfg.RelayIP, Port: port}, nil |
| 646 | } |
| 647 | return nil, nil, fmt.Errorf("relay: no free port in %d-%d", lo, hi) |
| 648 | } |
| 649 | |
| 650 | // AllocateConn would be a TCP relay allocation (RFC 6062), which we do not |
| 651 | // offer: a TURN client may reach us over TCP, but every relayed leg is UDP. |
| 652 | func (s *Server) AllocateConn(string, int) (net.Conn, net.Addr, error) { |
| 653 | return nil, nil, errTCPAllocUnsupported |
| 654 | } |
| 655 | |
| 656 | // --- pion handlers ------------------------------------------------------- |
| 657 | |
| 658 | // auth is pion's AuthHandler: called on every authenticated request, and |
| 659 | // the whole of spec §4's verification. It returns the key pion checks |
| 660 | // MESSAGE-INTEGRITY against, so a wrong credential fails inside pion and |
| 661 | // never reaches here. |
| 662 | func (s *Server) auth(username, realm string, src net.Addr) ([]byte, bool) { |
| 663 | now := s.now() |
| 664 | u, err := ParseUsername(username) |
| 665 | if err != nil { |
| 666 | return s.refused(Identity{}, "bad shape", "relay: auth refused from %s: %v", src, err) |
| 667 | } |
| 668 | id := Identity{Account: u.Account, App: u.App} |
| 669 | |
| 670 | if !u.Expiry.After(now) || u.Expiry.After(now.Add(MaxCredentialLife)) { |
| 671 | return s.refused(id, "expired", "relay: auth refused for %s/%s: expiry %s outside (now, now+%s]", |
| 672 | id.Account, id.App, u.Expiry.UTC().Format(time.RFC3339), MaxCredentialLife) |
| 673 | } |
| 674 | |
| 675 | s.mu.Lock() |
| 676 | bound, isBound := s.bound[typedSrc(src)] |
| 677 | s.mu.Unlock() |
| 678 | if isBound && (bound.ID != id || bound.Incarnation != u.Incarnation) { |
| 679 | return s.refused(id, "bound elsewhere", "relay: auth refused for %s/%s: source %s is bound to %s/%s", |
| 680 | id.Account, id.App, typedSrc(src), bound.ID.Account, bound.ID.App) |
| 681 | } |
| 682 | |
| 683 | app, ok := s.cfg.Authority().Lookup(u.Account, u.App) |
| 684 | switch { |
| 685 | case !ok: |
| 686 | return s.refused(id, "unknown app", "relay: auth refused for %s/%s: not in the authority record", id.Account, id.App) |
| 687 | case app.Incarnation != u.Incarnation: |
| 688 | return s.refused(id, "wrong incarnation", "relay: auth refused for %s/%s: incarnation %s, record has %s", |
| 689 | id.Account, id.App, u.Incarnation, app.Incarnation) |
| 690 | case !contains(app.Regions, s.cfg.Region): |
| 691 | return s.refused(id, "wrong region", "relay: auth refused for %s/%s: region %s not in %v", |
| 692 | id.Account, id.App, s.cfg.Region, app.Regions) |
| 693 | } |
| 694 | |
| 695 | masters := s.cfg.Masters() |
| 696 | if masters == nil { |
| 697 | return s.refused(id, "unknown kid", "relay: auth refused for %s/%s: no masters loaded", id.Account, id.App) |
| 698 | } |
| 699 | master, ok := masters.Lookup(u.Kid, now) |
| 700 | if !ok { |
| 701 | return s.refused(id, "unknown kid", "relay: auth refused for %s/%s: kid %s is unknown or retired", |
| 702 | id.Account, id.App, u.Kid) |
| 703 | } |
| 704 | |
| 705 | key := DeriveKey(master.Key, u.Account, u.App, u.Incarnation) |
| 706 | s.rememberAuth(typedSrc(src), u, now) |
| 707 | return turn.GenerateAuthKey(username, realm, Credential(key, username)), true |
| 708 | } |
| 709 | |
| 710 | // rememberAuth stores the username a source last authenticated with, for |
| 711 | // the allocation event that follows. pion verifies MESSAGE-INTEGRITY only |
| 712 | // after the handler returns, so this map is written for sources that have |
| 713 | // not proved anything yet: tick ages entries out, and this caps them at |
| 714 | // twice the box's live-allocation limit, dropping the oldest quarter when |
| 715 | // it fills. |
| 716 | func (s *Server) rememberAuth(key string, u Username, now time.Time) { |
| 717 | s.mu.Lock() |
| 718 | defer s.mu.Unlock() |
| 719 | if _, known := s.lastAuth[key]; !known && len(s.lastAuth) >= s.maxLastAuth { |
| 720 | type aged struct { |
| 721 | key string |
| 722 | at time.Time |
| 723 | } |
| 724 | all := make([]aged, 0, len(s.lastAuth)) |
| 725 | for k, r := range s.lastAuth { |
| 726 | all = append(all, aged{k, r.at}) |
| 727 | } |
| 728 | sort.Slice(all, func(i, j int) bool { return all[i].at.Before(all[j].at) }) |
| 729 | drop := len(all) / 4 |
| 730 | if drop == 0 { |
| 731 | drop = 1 |
| 732 | } |
| 733 | for _, a := range all[:drop] { |
| 734 | delete(s.lastAuth, a.key) |
| 735 | } |
| 736 | } |
| 737 | s.lastAuth[key] = authRec{u: u, at: now} |
| 738 | } |
| 739 | |
| 740 | // quota is pion's QuotaHandler, called on Allocate only: a refusal answers |
| 741 | // 486. The lease comes first, because a relay whose authority read is |
| 742 | // stale must take nothing new on. |
| 743 | func (s *Server) quota(username, _ string, src net.Addr) bool { |
| 744 | now := s.now() |
| 745 | if !s.cfg.Lease(now) { |
| 746 | s.log("relay: allocation refused: serving lease has lapsed") |
| 747 | return false |
| 748 | } |
| 749 | u, err := ParseUsername(username) |
| 750 | if err != nil { |
| 751 | return false // auth would already have refused this |
| 752 | } |
| 753 | id := Identity{Account: u.Account, App: u.App} |
| 754 | ok, reason := s.adm.Admit(id) |
| 755 | if !ok { |
| 756 | s.countRefusal(id, reason) |
| 757 | s.log("relay: allocation refused for %s/%s: %s", id.Account, id.App, reason) |
| 758 | return false |
| 759 | } |
| 760 | key := typedSrc(src) |
| 761 | s.mu.Lock() |
| 762 | old, had := s.admits[key] |
| 763 | s.admits[key] = admitRec{id: id, at: now} |
| 764 | s.mu.Unlock() |
| 765 | if had { |
| 766 | // A previous attempt from this source was admitted and never |
| 767 | // became an allocation; it owns no socket, so release it here. |
| 768 | s.adm.Release(old.id) |
| 769 | } |
| 770 | return true |
| 771 | } |
| 772 | |
| 773 | // created is pion's OnAllocationCreated, called with the relay address |
| 774 | // before pion starts reading from the socket. It is where the wrapper we |
| 775 | // handed out earlier learns whose allocation it is. |
| 776 | func (s *Server) created(src, _ net.Addr, _, _, _ string, relayAddr net.Addr, _ int) { |
| 777 | ua, ok := relayAddr.(*net.UDPAddr) |
| 778 | if !ok { |
| 779 | s.log("relay: allocation created with a non-UDP relay address %v", relayAddr) |
| 780 | return |
| 781 | } |
| 782 | key := typedSrc(src) |
| 783 | now := s.now() |
| 784 | |
| 785 | s.mu.Lock() |
| 786 | p, havePending := s.pending[ua.Port] |
| 787 | if !havePending { |
| 788 | // The sweep already reclaimed this socket, or it was never ours. |
| 789 | // Either way pion now owns an allocation no deadline of ours can |
| 790 | // end, so end it here by closing the socket it reads from. |
| 791 | orphan := s.byPort[ua.Port] |
| 792 | s.mu.Unlock() |
| 793 | if orphan != nil { |
| 794 | s.log("relay: allocation created on port %d after its socket was reclaimed: ending it", ua.Port) |
| 795 | orphan.Close() |
| 796 | } else { |
| 797 | s.log("relay: allocation created on port %d with no socket of ours", ua.Port) |
| 798 | } |
| 799 | return |
| 800 | } |
| 801 | delete(s.pending, ua.Port) |
| 802 | rec, haveAuth := s.lastAuth[key] |
| 803 | if !haveAuth { |
| 804 | s.mu.Unlock() |
| 805 | s.log("relay: allocation created for %s with no authenticated username", key) |
| 806 | p.conn.Close() |
| 807 | return |
| 808 | } |
| 809 | c := p.conn |
| 810 | c.b.ID = Identity{Account: rec.u.Account, App: rec.u.App} |
| 811 | c.b.Expiry = rec.u.Expiry |
| 812 | c.b.Kid = rec.u.Kid |
| 813 | c.b.Incarnation = rec.u.Incarnation |
| 814 | c.b.Src = key |
| 815 | s.seq++ |
| 816 | e := &allocEntry{conn: c, id: c.b.ID, key: key, seq: s.seq, flow: p.flow} |
| 817 | s.allocs[key] = e |
| 818 | s.owners[c] = e |
| 819 | s.bound[key] = c.b |
| 820 | delete(s.admits, key) |
| 821 | expiry := rec.u.Expiry |
| 822 | s.mu.Unlock() |
| 823 | |
| 824 | // The credential's own deadline. Set outside the lock: a timer whose |
| 825 | // deadline has already passed fires on the spot, and closing takes the |
| 826 | // lock we would still be holding. |
| 827 | t := time.AfterFunc(expiry.Sub(now), func() { c.Close() }) |
| 828 | s.mu.Lock() |
| 829 | if cur, ok := s.allocs[key]; ok && cur == e { |
| 830 | e.timer = t |
| 831 | } else { |
| 832 | t.Stop() |
| 833 | } |
| 834 | s.mu.Unlock() |
| 835 | s.log("relay: allocation for %s/%s on %s from %s until %s", |
| 836 | c.b.ID.Account, c.b.ID.App, relayAddr, key, expiry.UTC().Format(time.RFC3339)) |
| 837 | } |
| 838 | |
| 839 | // release is the wrapped socket's onClose, whoever closed it: pion on a |
| 840 | // read error, a timer, tick, EndWhere. Its state is keyed on this socket, |
| 841 | // not on the typed source, so a replacement allocation bound for the same |
| 842 | // source while this one was closing (pion removes an allocation from its |
| 843 | // manager before closing it) keeps its binding and this one still gives |
| 844 | // its admission back. |
| 845 | func (s *Server) release(port int, c *relayConn) { |
| 846 | s.ports.remove(port) |
| 847 | var id Identity |
| 848 | var release bool |
| 849 | var last int64 |
| 850 | s.mu.Lock() |
| 851 | if p, ok := s.pending[port]; ok && p.conn == c { |
| 852 | delete(s.pending, port) |
| 853 | last = p.flow.flush() |
| 854 | } |
| 855 | if cur, ok := s.byPort[port]; ok && cur == c { |
| 856 | delete(s.byPort, port) |
| 857 | } |
| 858 | if e, ok := s.owners[c]; ok { |
| 859 | last = e.flow.flush() |
| 860 | delete(s.owners, c) |
| 861 | if e.timer != nil { |
| 862 | e.timer.Stop() |
| 863 | } |
| 864 | if cur, ok := s.allocs[e.key]; ok && cur == e { |
| 865 | delete(s.allocs, e.key) |
| 866 | } |
| 867 | if b, ok := s.bound[e.key]; ok && b == c.b { |
| 868 | delete(s.bound, e.key) |
| 869 | } |
| 870 | id, release = e.id, true |
| 871 | } |
| 872 | s.mu.Unlock() |
| 873 | if release { |
| 874 | s.adm.Release(id) |
| 875 | } |
| 876 | if last > 0 { |
| 877 | // The last peer packet was read and never forwarded. |
| 878 | s.countRejected(c.b.ID, last) |
| 879 | } |
| 880 | } |
| 881 | |
| 882 | // permit is pion's PermissionHandler: it sees only a peer IP, so the port |
| 883 | // half of the EIP rule lives in relayConn.WriteTo. |
| 884 | func (s *Server) permit(client net.Addr, peer net.IP) bool { |
| 885 | deny := func(why string) bool { |
| 886 | s.mu.Lock() |
| 887 | b, ok := s.bound[typedSrc(client)] |
| 888 | var id Identity |
| 889 | if ok { |
| 890 | id = b.ID |
| 891 | } |
| 892 | s.mu.Unlock() |
| 893 | s.countRefusal(id, "peer denied") |
| 894 | s.log("relay: permission refused for %s to %s: %s", client, peer, why) |
| 895 | return false |
| 896 | } |
| 897 | if peer == nil { |
| 898 | return deny("unspecified address") |
| 899 | } |
| 900 | // Our own EIP is allowed: two clients that both relay here hold relay |
| 901 | // candidates on it and must reach each other. |
| 902 | if s.cfg.RelayIP != nil && peer.Equal(s.cfg.RelayIP) { |
| 903 | return true |
| 904 | } |
| 905 | if why := s.peerRefusal(peer); why != "" { |
| 906 | return deny(why) |
| 907 | } |
| 908 | // A NAT64 or 6to4 address is a route to the IPv4 address inside it, so |
| 909 | // that address has to pass too. |
| 910 | if v4 := embeddedV4(peer); v4 != nil { |
| 911 | if why := s.peerRefusal(v4); why != "" { |
| 912 | return deny(why + " (embedded in " + peer.String() + ")") |
| 913 | } |
| 914 | } |
| 915 | return true |
| 916 | } |
| 917 | |
| 918 | // peerRefusal is permit's verdict on one address, "" when it may be reached. |
| 919 | func (s *Server) peerRefusal(peer net.IP) string { |
| 920 | switch { |
| 921 | case peer.IsUnspecified(): |
| 922 | return "unspecified address" |
| 923 | case peer.IsMulticast(): |
| 924 | return "multicast address" |
| 925 | } |
| 926 | // ExtraAllow is the operator's (and the test fixture's) way to permit |
| 927 | // a range the built-in list denies. Empty on a real box. |
| 928 | for _, n := range s.allow { |
| 929 | if n.Contains(peer) { |
| 930 | return "" |
| 931 | } |
| 932 | } |
| 933 | for _, n := range s.deny { |
| 934 | if n.Contains(peer) { |
| 935 | return "denied range " + n.String() |
| 936 | } |
| 937 | } |
| 938 | for _, ip := range s.local { |
| 939 | if peer.Equal(ip) { |
| 940 | return "the relay's own address" |
| 941 | } |
| 942 | } |
| 943 | return "" |
| 944 | } |
| 945 | |
| 946 | // --- metering ------------------------------------------------------------ |
| 947 | |
| 948 | // countIn is the client-to-peer leg, counted at the relay socket after |
| 949 | // pion forwarded it. |
| 950 | func (s *Server) countIn(id Identity, n int) { |
| 951 | if s.cfg.Meter != nil { |
| 952 | s.cfg.Meter.Add(id, int64(n), 0, 0) |
| 953 | } |
| 954 | if s.adm.AddBytes(id, int64(n)) { |
| 955 | s.overBudget(id) |
| 956 | } |
| 957 | } |
| 958 | |
| 959 | // countOut is the peer-to-client leg, counted at the listener socket and |
| 960 | // attributed through the owner binding. |
| 961 | func (s *Server) countOut(id Identity, n int) { |
| 962 | if s.cfg.Meter != nil { |
| 963 | s.cfg.Meter.Add(id, 0, int64(n), 0) |
| 964 | } |
| 965 | if s.adm.AddBytes(id, int64(n)) { |
| 966 | s.overBudget(id) |
| 967 | } |
| 968 | } |
| 969 | |
| 970 | // countRejected is spec §3's `rejected`: peer bytes that reached a relay |
| 971 | // socket and were dropped for want of a permission. Metered, never charged |
| 972 | // to a budget. |
| 973 | func (s *Server) countRejected(id Identity, n int64) { |
| 974 | if s.cfg.Meter != nil { |
| 975 | s.cfg.Meter.Add(id, 0, 0, n) |
| 976 | } |
| 977 | } |
| 978 | |
| 979 | // countGated is the other kind of drop: a client packet aimed at our own |
| 980 | // EIP on a port that is not a live allocation. It is a policy refusal, not |
| 981 | // a meter line, so it is counted per app and goes no further. |
| 982 | func (s *Server) countGated(id Identity, _ int) { |
| 983 | s.countRefusal(id, "gated") |
| 984 | } |
| 985 | |
| 986 | // overBudget ends an app's allocations once its rolling-hour budget is |
| 987 | // crossed, because a budget that only stops new allocations bounds nothing. |
| 988 | // It runs off the forwarding path, once per identity at a time. |
| 989 | func (s *Server) overBudget(id Identity) { |
| 990 | s.mu.Lock() |
| 991 | if s.shedding[id] { |
| 992 | s.mu.Unlock() |
| 993 | return |
| 994 | } |
| 995 | s.shedding[id] = true |
| 996 | s.mu.Unlock() |
| 997 | go func() { |
| 998 | s.EndWhere(func(b *Binding) bool { return b.ID == id }, "byte budget") |
| 999 | s.mu.Lock() |
| 1000 | delete(s.shedding, id) |
| 1001 | s.mu.Unlock() |
| 1002 | }() |
| 1003 | } |
| 1004 | |
| 1005 | // attrib is which identity a refusal may be counted against. pion hands |
| 1006 | // the AuthHandler whatever username arrived, before any integrity check, |
| 1007 | // so an unauthenticated sender picks the account and app strings. Only an |
| 1008 | // app the authority record actually names gets a row of its own; every |
| 1009 | // other refusal shares the zero identity. |
| 1010 | func (s *Server) attrib(id Identity) Identity { |
| 1011 | if id.Account == "" || id.App == "" { |
| 1012 | return Identity{} |
| 1013 | } |
| 1014 | if _, ok := s.cfg.Authority().Lookup(id.Account, id.App); !ok { |
| 1015 | return Identity{} |
| 1016 | } |
| 1017 | return id |
| 1018 | } |
| 1019 | |
| 1020 | func (s *Server) countRefusal(id Identity, reason string) { |
| 1021 | id = s.attrib(id) |
| 1022 | s.mu.Lock() |
| 1023 | m := s.refusals[id] |
| 1024 | if m == nil && len(s.refusals) >= maxRefusalIdentities { |
| 1025 | id = Identity{} |
| 1026 | m = s.refusals[id] |
| 1027 | } |
| 1028 | if m == nil { |
| 1029 | m = map[string]int{} |
| 1030 | s.refusals[id] = m |
| 1031 | } |
| 1032 | m[reason]++ |
| 1033 | s.mu.Unlock() |
| 1034 | } |
| 1035 | |
| 1036 | // mayLog rate-limits one identity's one refusal reason to a line a minute, |
| 1037 | // so a flood of refusals cannot be turned into a flood of log. |
| 1038 | func (s *Server) mayLog(id Identity, reason string) bool { |
| 1039 | k := logKey{id: s.attrib(id), reason: reason} |
| 1040 | now := s.now() |
| 1041 | s.mu.Lock() |
| 1042 | defer s.mu.Unlock() |
| 1043 | if at, ok := s.logged[k]; ok { |
| 1044 | if now.Sub(at) < refusalLogEvery { |
| 1045 | return false |
| 1046 | } |
| 1047 | } else if len(s.logged) >= maxLoggedRefusals { |
| 1048 | return false |
| 1049 | } |
| 1050 | s.logged[k] = now |
| 1051 | return true |
| 1052 | } |
| 1053 | |
| 1054 | // refused counts a refusal against the app and logs why. Its return values |
| 1055 | // are the AuthHandler's, so a refusal is one line at the call site. |
| 1056 | func (s *Server) refused(id Identity, reason, format string, args ...any) ([]byte, bool) { |
| 1057 | s.countRefusal(id, reason) |
| 1058 | if s.mayLog(id, reason) { |
| 1059 | s.log(format, args...) |
| 1060 | } |
| 1061 | return nil, false |
| 1062 | } |
| 1063 | |
| 1064 | func (s *Server) refusalCount(id Identity, reason string) int { |
| 1065 | s.mu.Lock() |
| 1066 | defer s.mu.Unlock() |
| 1067 | return s.refusals[id][reason] |
| 1068 | } |
| 1069 | |
| 1070 | func (s *Server) refusalIdentities() int { |
| 1071 | s.mu.Lock() |
| 1072 | defer s.mu.Unlock() |
| 1073 | return len(s.refusals) |
| 1074 | } |
| 1075 | |
| 1076 | // entryFor is the owner binding lookup the out leg is attributed through. |
| 1077 | func (s *Server) entryFor(key string) *allocEntry { |
| 1078 | s.mu.Lock() |
| 1079 | defer s.mu.Unlock() |
| 1080 | return s.allocs[key] |
| 1081 | } |
| 1082 | |
| 1083 | // --- listener wrappers --------------------------------------------------- |
| 1084 | |
| 1085 | // listenerConn wraps the UDP listener pion answers clients on. It mirrors |
| 1086 | // relayConn without the EIP gate: everything written here goes to a client |
| 1087 | // that asked us for it, so the only questions are whose bytes they are and |
| 1088 | // whether the buckets still have room. |
| 1089 | type listenerConn struct { |
| 1090 | net.PacketConn |
| 1091 | s *Server |
| 1092 | } |
| 1093 | |
| 1094 | func (c *listenerConn) WriteTo(p []byte, addr net.Addr) (int, error) { |
| 1095 | // A TURN response is the client asking us something, not relayed |
| 1096 | // media: bucketing it would drop Refresh responses at the app's rate |
| 1097 | // cap and end calls for a reason spec §3 does not list, and metering |
| 1098 | // it would bill the client for its own signalling. |
| 1099 | if !relayedPayload(p) { |
| 1100 | return c.PacketConn.WriteTo(p, addr) |
| 1101 | } |
| 1102 | e := c.s.entryFor(typedSrc(addr)) |
| 1103 | if e != nil { |
| 1104 | // Peek both, then spend both: a box refusal must not leave the |
| 1105 | // app's bucket debited (see relayConn.WriteTo). |
| 1106 | if e.conn.appBucket != nil && !e.conn.appBucket.Peek(len(p)) { |
| 1107 | return len(p), nil |
| 1108 | } |
| 1109 | if c.s.box != nil && !c.s.box.Peek(len(p)) { |
| 1110 | return len(p), nil |
| 1111 | } |
| 1112 | if e.conn.appBucket != nil { |
| 1113 | e.conn.appBucket.Spend(len(p)) |
| 1114 | } |
| 1115 | if c.s.box != nil { |
| 1116 | c.s.box.Spend(len(p)) |
| 1117 | } |
| 1118 | } |
| 1119 | n, err := c.PacketConn.WriteTo(p, addr) |
| 1120 | if n > 0 && e != nil { |
| 1121 | e.flow.forwarded() |
| 1122 | c.s.countOut(e.id, n) |
| 1123 | } |
| 1124 | return n, err |
| 1125 | } |
| 1126 | |
| 1127 | // relayedPayload reports whether a packet bound for a client carries peer |
| 1128 | // media rather than TURN signalling: a ChannelData message (first two bits |
| 1129 | // 0b01, so 0x40 to 0x7f) or a Data indication. |
| 1130 | func relayedPayload(p []byte) bool { |
| 1131 | if len(p) == 0 { |
| 1132 | return false |
| 1133 | } |
| 1134 | if p[0]&0xc0 == 0x40 { |
| 1135 | return true |
| 1136 | } |
| 1137 | if !stun.IsMessage(p) { |
| 1138 | return false |
| 1139 | } |
| 1140 | var t stun.MessageType |
| 1141 | t.ReadValue(binary.BigEndian.Uint16(p[0:2])) |
| 1142 | return t.Method == stun.MethodData && t.Class == stun.ClassIndication |
| 1143 | } |
| 1144 | |
| 1145 | // countingListener wraps the TCP listener so the out leg is metered for |
| 1146 | // TCP clients too. A TCP stream cannot have bytes dropped out of it the |
| 1147 | // way a datagram can, so the buckets are spent but never enforced here. |
| 1148 | type countingListener struct { |
| 1149 | net.Listener |
| 1150 | s *Server |
| 1151 | } |
| 1152 | |
| 1153 | func (l *countingListener) Accept() (net.Conn, error) { |
| 1154 | c, err := l.Listener.Accept() |
| 1155 | if err != nil { |
| 1156 | return nil, err |
| 1157 | } |
| 1158 | return &countingConn{Conn: c, s: l.s, key: typedSrc(c.RemoteAddr())}, nil |
| 1159 | } |
| 1160 | |
| 1161 | type countingConn struct { |
| 1162 | net.Conn |
| 1163 | s *Server |
| 1164 | key string |
| 1165 | } |
| 1166 | |
| 1167 | func (c *countingConn) Write(p []byte) (int, error) { |
| 1168 | payload := relayedPayload(p) |
| 1169 | n, err := c.Conn.Write(p) |
| 1170 | if n > 0 && payload { |
| 1171 | if e := c.s.entryFor(c.key); e != nil { |
| 1172 | if e.conn.appBucket != nil { |
| 1173 | e.conn.appBucket.Spend(n) |
| 1174 | } |
| 1175 | if c.s.box != nil { |
| 1176 | c.s.box.Spend(n) |
| 1177 | } |
| 1178 | e.flow.forwarded() |
| 1179 | c.s.countOut(e.id, n) |
| 1180 | } |
| 1181 | } |
| 1182 | return n, err |
| 1183 | } |
| 1184 | |
| 1185 | func contains(ss []string, s string) bool { |
| 1186 | for _, x := range ss { |
| 1187 | if x == s { |
| 1188 | return true |
| 1189 | } |
| 1190 | } |
| 1191 | return false |
| 1192 | } |
| 1193 | |
amadan