package group import ( "encoding/json" "errors" "log" "os" "path" "path/filepath" "sort" "strings" "sync" "time" "github.com/pion/ice/v2" "github.com/pion/sdp/v3" "github.com/pion/webrtc/v3" ) var Directory string var UseMDNS bool var UDPMin, UDPMax uint16 var ErrNotAuthorised = errors.New("not authorised") type UserError string func (err UserError) Error() string { return string(err) } type KickError struct { Id string Username string Message string } func (err KickError) Error() string { m := "kicked out" if err.Message != "" { m += "(" + err.Message + ")" } if err.Username != "" { m += " by " + err.Username } return m } type ProtocolError string func (err ProtocolError) Error() string { return string(err) } type ChatHistoryEntry struct { Id string User string Time int64 Kind string Value interface{} } const ( LowBitrate = 100000 MinBitrate = 2 * LowBitrate ) type Group struct { name string mu sync.Mutex description *Description locked *string clients map[string]Client history []ChatHistoryEntry timestamp time.Time } func (g *Group) Name() string { return g.name } func (g *Group) Locked() (bool, string) { g.mu.Lock() defer g.mu.Unlock() if g.locked != nil { return true, *g.locked } else { return false, "" } } func (g *Group) SetLocked(locked bool, message string) { g.mu.Lock() defer g.mu.Unlock() if locked { g.locked = &message } else { g.locked = nil } } func (g *Group) Public() bool { g.mu.Lock() defer g.mu.Unlock() return g.description.Public } func (g *Group) Redirect() string { g.mu.Lock() defer g.mu.Unlock() return g.description.Redirect } func (g *Group) AllowRecording() bool { g.mu.Lock() defer g.mu.Unlock() return g.description.AllowRecording } var groups struct { mu sync.Mutex groups map[string]*Group } func (g *Group) API() (*webrtc.API, error) { g.mu.Lock() codecs := g.description.Codecs g.mu.Unlock() return APIFromNames(codecs) } func codecFromName(name string) (webrtc.RTPCodecCapability, error) { switch name { case "vp8": return webrtc.RTPCodecCapability{ "video/VP8", 90000, 0, "", nil, }, nil case "vp9": return webrtc.RTPCodecCapability{ "video/VP9", 90000, 0, "profile-id=0", nil, }, nil case "h264": return webrtc.RTPCodecCapability{ "video/H264", 90000, 0, "level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=42001f", nil, }, nil case "opus": return webrtc.RTPCodecCapability{ "audio/opus", 48000, 2, "minptime=10;useinbandfec=1;stereo=1;sprop-stereo=1", nil, }, nil case "g722": return webrtc.RTPCodecCapability{ "audio/G722", 8000, 1, "", nil, }, nil case "pcmu": return webrtc.RTPCodecCapability{ "audio/PCMU", 8000, 1, "", nil, }, nil case "pcma": return webrtc.RTPCodecCapability{ "audio/PCMA", 8000, 1, "", nil, }, nil default: return webrtc.RTPCodecCapability{}, errors.New("unknown codec") } } func payloadType(codec webrtc.RTPCodecCapability) (webrtc.PayloadType, error) { switch strings.ToLower(codec.MimeType) { case "video/vp8": return 96, nil case "video/vp9": return 98, nil case "video/h264": return 102, nil case "audio/opus": return 111, nil case "audio/g722": return 9, nil case "audio/pcmu": return 0, nil case "audio/pcma": return 8, nil default: return 0, errors.New("unknown codec") } } func APIFromCodecs(codecs []webrtc.RTPCodecCapability) (*webrtc.API, error) { s := webrtc.SettingEngine{} s.SetSRTPReplayProtectionWindow(512) if !UseMDNS { s.SetICEMulticastDNSMode(ice.MulticastDNSModeDisabled) } m := webrtc.MediaEngine{} for _, codec := range codecs { var tpe webrtc.RTPCodecType var fb []webrtc.RTCPFeedback if strings.HasPrefix(strings.ToLower(codec.MimeType), "video/") { tpe = webrtc.RTPCodecTypeVideo fb = []webrtc.RTCPFeedback{ {"goog-remb", ""}, {"nack", ""}, {"nack", "pli"}, {"ccm", "fir"}, } } else if strings.HasPrefix(strings.ToLower(codec.MimeType), "audio/") { tpe = webrtc.RTPCodecTypeAudio fb = []webrtc.RTCPFeedback{} } else { continue } ptpe, err := payloadType(codec) if err != nil { log.Printf("%v", err) continue } err = m.RegisterCodec( webrtc.RTPCodecParameters{ RTPCodecCapability: webrtc.RTPCodecCapability{ MimeType: codec.MimeType, ClockRate: codec.ClockRate, Channels: codec.Channels, SDPFmtpLine: codec.SDPFmtpLine, RTCPFeedback: fb, }, PayloadType: ptpe, }, tpe, ) if err != nil { log.Printf("%v", err) continue } } if UDPMin > 0 && UDPMax > 0 { s.SetEphemeralUDPPortRange(UDPMin, UDPMax) } m.RegisterHeaderExtension( webrtc.RTPHeaderExtensionCapability{sdp.SDESMidURI}, webrtc.RTPCodecTypeVideo) m.RegisterHeaderExtension( webrtc.RTPHeaderExtensionCapability{sdp.SDESRTPStreamIDURI}, webrtc.RTPCodecTypeVideo) return webrtc.NewAPI( webrtc.WithSettingEngine(s), webrtc.WithMediaEngine(&m), ), nil } func APIFromNames(names []string) (*webrtc.API, error) { if len(names) == 0 { names = []string{"vp8", "opus"} } codecs := make([]webrtc.RTPCodecCapability, 0, len(names)) for _, n := range names { codec, err := codecFromName(n) if err != nil { log.Printf("Codec %v: %v", n, err) continue } codecs = append(codecs, codec) } return APIFromCodecs(codecs) } func Add(name string, desc *Description) (*Group, error) { if name == "" || strings.HasSuffix(name, "/") { return nil, UserError("illegal group name") } groups.mu.Lock() defer groups.mu.Unlock() if groups.groups == nil { groups.groups = make(map[string]*Group) } var err error g := groups.groups[name] if g == nil { if desc == nil { desc, err = GetDescription(name) if err != nil { return nil, err } } g = &Group{ name: name, description: desc, clients: make(map[string]Client), timestamp: time.Now(), } autoLockKick(g, g.getClientsUnlocked(nil)) groups.groups[name] = g return g, nil } g.mu.Lock() defer g.mu.Unlock() if desc != nil { g.description = desc } else if !descriptionChanged(name, g.description) { return g, nil } desc, err = GetDescription(name) if err != nil { if !os.IsNotExist(err) { log.Printf("Reading group %v: %v", name, err) } deleteUnlocked(g) return nil, err } g.description = desc autoLockKick(g, g.getClientsUnlocked(nil)) return g, nil } func Range(f func(g *Group) bool) { groups.mu.Lock() defer groups.mu.Unlock() for _, g := range groups.groups { ok := f(g) if !ok { break } } } func GetNames() []string { names := make([]string, 0) Range(func(g *Group) bool { names = append(names, g.name) return true }) return names } type SubGroup struct { Name string Clients int } func GetSubGroups(parent string) []SubGroup { prefix := parent + "/" subgroups := make([]SubGroup, 0) Range(func(g *Group) bool { if strings.HasPrefix(g.name, prefix) { g.mu.Lock() count := len(g.clients) g.mu.Unlock() if count > 0 { subgroups = append(subgroups, SubGroup{g.name, count}) } } return true }) return subgroups } func Get(name string) *Group { groups.mu.Lock() defer groups.mu.Unlock() return groups.groups[name] } func Delete(name string) bool { groups.mu.Lock() defer groups.mu.Unlock() g := groups.groups[name] if g == nil { return false } g.mu.Lock() defer g.mu.Unlock() return deleteUnlocked(g) } // Called with both groups.mu and g.mu taken. func deleteUnlocked(g *Group) bool { if len(g.clients) != 0 { return false } delete(groups.groups, g.name) return true } func Expire() { names := GetNames() now := time.Now() for _, name := range names { g := Get(name) if g == nil { continue } old := false g.mu.Lock() empty := len(g.clients) == 0 if empty && !g.description.Public { age := now.Sub(g.timestamp) old = age > maxHistoryAge(g.description) } // We cannot take groups.mu at this point without a deadlock. g.mu.Unlock() if empty && old { // Delete will check if the group is still empty Delete(name) } } } func AddClient(group string, c Client) (*Group, error) { g, err := Add(group, nil) if err != nil { return nil, err } g.mu.Lock() defer g.mu.Unlock() clients := g.getClientsUnlocked(nil) if !c.OverridePermissions(g) { perms, err := g.description.GetPermission(group, c) if err != nil { return nil, err } c.SetPermissions(perms) if !perms.Op { if g.locked != nil { m := *g.locked if m == "" { m = "this group is locked" } return nil, UserError(m) } if g.description.Autokick { ops := false for _, c := range clients { if c.Permissions().Op { ops = true break } } if !ops { return nil, UserError( "there are no operators " + "in this group", ) } } } if !perms.Op && g.description.MaxClients > 0 { if len(g.clients) >= g.description.MaxClients { return nil, UserError("too many users") } } } if g.clients[c.Id()] != nil { return nil, ProtocolError("duplicate client id") } g.clients[c.Id()] = c g.timestamp = time.Now() id := c.Id() u := c.Username() p := c.Permissions() s := c.Status() c.PushClient(c.Id(), u, &p, s, "add") for _, cc := range clients { pp := cc.Permissions() c.PushClient(cc.Id(), cc.Username(), &pp, cc.Status(), "add") cc.PushClient(id, u, &p, s, "add") } return g, nil } // called locked func autoLockKick(g *Group, clients []Client) { if !(g.description.Autolock && g.locked == nil) && !g.description.Autokick { return } for _, c := range clients { if c.Permissions().Op { return } } if g.description.Autolock && g.locked == nil { m := "this group is locked" g.locked = &m } if g.description.Autokick { go kickall(g, "there are no operators in this group") } } func DelClient(c Client) { g := c.Group() if g == nil { return } g.mu.Lock() defer g.mu.Unlock() if g.clients[c.Id()] != c { log.Printf("Deleting unknown client") return } delete(g.clients, c.Id()) g.timestamp = time.Now() clients := g.getClientsUnlocked(nil) go func(clients []Client) { for _, cc := range clients { cc.PushClient(c.Id(), "", nil, nil, "delete") } }(clients) autoLockKick(g, clients) } func (g *Group) GetClients(except Client) []Client { g.mu.Lock() defer g.mu.Unlock() return g.getClientsUnlocked(except) } func (g *Group) getClientsUnlocked(except Client) []Client { clients := make([]Client, 0, len(g.clients)) for _, c := range g.clients { if c != except { clients = append(clients, c) } } return clients } func (g *Group) GetClient(id string) Client { g.mu.Lock() defer g.mu.Unlock() return g.getClientUnlocked(id) } func (g *Group) getClientUnlocked(id string) Client { for idd, c := range g.clients { if idd == id { return c } } return nil } func (g *Group) Range(f func(c Client) bool) { g.mu.Lock() defer g.mu.Unlock() for _, c := range g.clients { ok := f(c) if !ok { break } } } func kickall(g *Group, message string) { g.Range(func(c Client) bool { c.Kick("", "", message) return true }) } func (g *Group) Shutdown(message string) { kickall(g, message) } type warner interface { Warn(oponly bool, message string) error } func (g *Group) WallOps(message string) { clients := g.GetClients(nil) for _, c := range clients { w, ok := c.(warner) if !ok { continue } err := w.Warn(true, message) if err != nil { log.Printf("WallOps: %v", err) } } } func FromJSTime(tm int64) time.Time { if tm == 0 { return time.Time{} } return time.Unix(int64(tm)/1000, (int64(tm)%1000)*1000000) } func ToJSTime(tm time.Time) int64 { return int64((tm.Sub(time.Unix(0, 0)) + time.Millisecond/2) / time.Millisecond) } const maxChatHistory = 50 func (g *Group) ClearChatHistory() { g.mu.Lock() defer g.mu.Unlock() g.history = nil } func (g *Group) AddToChatHistory(id, user string, time int64, kind string, value interface{}) { g.mu.Lock() defer g.mu.Unlock() if len(g.history) >= maxChatHistory { copy(g.history, g.history[1:]) g.history = g.history[:len(g.history)-1] } g.history = append(g.history, ChatHistoryEntry{Id: id, User: user, Time: time, Kind: kind, Value: value}, ) } func discardObsoleteHistory(h []ChatHistoryEntry, duration time.Duration) []ChatHistoryEntry { i := 0 for i < len(h) { if time.Since(FromJSTime(h[i].Time)) <= duration { break } i++ } if i > 0 { copy(h, h[i:]) h = h[:len(h)-i] } return h } func (g *Group) GetChatHistory() []ChatHistoryEntry { g.mu.Lock() defer g.mu.Unlock() g.history = discardObsoleteHistory( g.history, maxHistoryAge(g.description), ) h := make([]ChatHistoryEntry, len(g.history)) copy(h, g.history) return h } func matchClient(group string, c Challengeable, users []ClientCredentials) (bool, bool) { matched := false for _, u := range users { if u.Username == c.Username() { matched = true if c.Challenge(group, u) { return true, true } } } if matched { return true, false } for _, u := range users { if u.Username == "" { if c.Challenge(group, u) { return true, true } } } return false, false } // Type Description represents a group description together with some // metadata about the JSON file it was deserialised from. type Description struct { // The file this was deserialised from. This is not necessarily // the name of the group, for example in case of a subgroup. FileName string `json:"-"` // The modtime and size of the file. These are used to detect // when a file has changed on disk. modTime time.Time `json:"-"` fileSize int64 `json:"-"` // A user-readable description of the group. Description string `json:"description,omitempty"` // A user-readable contact, typically an e-mail address. Contact string `json:"contact,omitempty"` // A user-readable comment. Ignored by the server. Comment string `json:"comment,omitempty"` // Whether to display the group on the landing page. Public bool `json:"public,omitempty"` // A URL to redirect the group to. If this is not empty, most // other fields are ignored. Redirect string `json:"redirect,omitempty"` // The maximum number of simultaneous clients. Unlimited if 0. MaxClients int `json:"max-clients,omitempty"` // The time for which history entries are kept. MaxHistoryAge int `json:"max-history-age,omitempty"` // Whether users are allowed to log in with an empty username. AllowAnonymous bool `json:"allow-anonymous,omitempty"` // Whether recording is allowed. AllowRecording bool `json:"allow-recording,omitempty"` // Whether subgroups are created on the fly. AllowSubgroups bool `json:"allow-subgroups,omitempty"` // Whether to lock the group when the last op logs out. Autolock bool `json:"autolock,omitempty"` // Whether to kick all users when the last op logs out. Autokick bool `json:"autokick,omitempty"` // A list of logins for ops. Op []ClientCredentials `json:"op,omitempty"` // A list of logins for presenters. Presenter []ClientCredentials `json:"presenter,omitempty"` // A list of logins for non-presenting users. Other []ClientCredentials `json:"other,omitempty"` // Codec preferences. If empty, a suitable default is chosen in // the APIFromNames function. Codecs []string `json:"codecs,omitempty"` } const DefaultMaxHistoryAge = 4 * time.Hour func maxHistoryAge(desc *Description) time.Duration { if desc.MaxHistoryAge != 0 { return time.Duration(desc.MaxHistoryAge) * time.Second } return DefaultMaxHistoryAge } func openDescriptionFile(name string) (*os.File, string, bool, error) { isParent := false for name != "" { fileName := filepath.Join( Directory, path.Clean("/"+name)+".json", ) r, err := os.Open(fileName) if !os.IsNotExist(err) { return r, fileName, isParent, err } isParent = true name, _ = path.Split(name) name = strings.TrimRight(name, "/") } return nil, "", false, os.ErrNotExist } func statDescriptionFile(name string) (os.FileInfo, string, bool, error) { isParent := false for name != "" { fileName := filepath.Join( Directory, path.Clean("/"+name)+".json", ) fi, err := os.Stat(fileName) if !os.IsNotExist(err) { return fi, fileName, isParent, err } isParent = true name, _ = path.Split(name) name = strings.TrimRight(name, "/") } return nil, "", false, os.ErrNotExist } // descriptionChanged returns true if a group's description may have // changed since it was last read. func descriptionChanged(name string, desc *Description) bool { fi, fileName, _, err := statDescriptionFile(name) if err != nil || fileName != desc.FileName { return true } if fi.Size() != desc.fileSize || fi.ModTime() != desc.modTime { return true } return false } func GetDescription(name string) (*Description, error) { r, fileName, isParent, err := openDescriptionFile(name) if err != nil { return nil, err } defer r.Close() var desc Description fi, err := r.Stat() if err != nil { return nil, err } d := json.NewDecoder(r) d.DisallowUnknownFields() err = d.Decode(&desc) if err != nil { return nil, err } if isParent { if !desc.AllowSubgroups { return nil, os.ErrNotExist } desc.Public = false desc.Description = "" } desc.FileName = fileName desc.fileSize = fi.Size() desc.modTime = fi.ModTime() return &desc, nil } func (desc *Description) GetPermission(group string, c Challengeable) (ClientPermissions, error) { var p ClientPermissions if !desc.AllowAnonymous && c.Username() == "" { return p, UserError("anonymous users not allowed in this group, please choose a username") } if found, good := matchClient(group, c, desc.Op); found { if good { p.Op = true p.Present = true if desc.AllowRecording { p.Record = true } return p, nil } return p, ErrNotAuthorised } if found, good := matchClient(group, c, desc.Presenter); found { if good { p.Present = true return p, nil } return p, ErrNotAuthorised } if found, good := matchClient(group, c, desc.Other); found { if good { return p, nil } return p, ErrNotAuthorised } return p, ErrNotAuthorised } type Public struct { Name string `json:"name"` Description string `json:"description,omitempty"` ClientCount int `json:"clientCount"` } func GetPublic() []Public { gs := make([]Public, 0) Range(func(g *Group) bool { if g.Public() { gs = append(gs, Public{ Name: g.name, Description: g.description.Description, ClientCount: len(g.clients), }) } return true }) sort.Slice(gs, func(i, j int) bool { return gs[i].Name < gs[j].Name }) return gs } func ReadPublicGroups() { err := filepath.Walk( Directory, func(path string, fi os.FileInfo, err error) error { if err != nil { log.Printf("Group file %v: %v", path, err) return nil } if fi.IsDir() { return nil } filename, err := filepath.Rel(Directory, path) if err != nil { log.Printf("Group file %v: %v", path, err) return nil } if !strings.HasSuffix(filename, ".json") { log.Printf( "Unexpected extension for group file %v", path, ) return nil } name := filename[:len(filename)-5] desc, err := GetDescription(name) if err != nil { log.Printf("Group file %v: %v", path, err) return nil } if desc.Public { Add(name, desc) } return nil }, ) if err != nil { log.Printf("Couldn't read groups: %v", err) } }