Add NickServ "CLIENTS LIST" and "CLIENTS LOGOUT".

CLIENTS LIST shows information about clients attached to a nick.
CLIENTS LOGOUT allows individual (or all) sessions to be logged out.

SESSIONS is now an alias for CLIENTS LIST.

Fixes #1072.

irc/client.go

@@ -90,6 +90,7 @@ type Client struct {
 	lastSeen           map[string]time.Time // maps device ID (including "") to time of last received command
 	lastSeenLastWrite  time.Time            // last time `lastSeen` was written to the datastore
 	loginThrottle      connection_limits.GenericThrottle
+	nextSessionID      int64 // Incremented when a new session is established
 	nick               string
 	nickCasefolded     string
 	nickMaskCasefolded string
@@ -150,6 +151,7 @@ type Session struct {
 	idleTimer  *time.Timer
 	pingSent   bool // we sent PING to a putatively idle connection and we're waiting for PONG
 
+	sessionID   int64
 	socket      *Socket
 	realIP      net.IP
 	proxiedIP   net.IP
@@ -353,6 +355,7 @@ func (server *Server) RunClient(conn IRCConn) {
 		realIP:         realIP,
 		proxiedIP:      proxiedIP,
 		requireSASL:    requireSASL,
+		nextSessionID:  1,
 	}
 	if requireSASL {
 		client.requireSASLMessage = banMsg
@@ -420,6 +423,8 @@ func (server *Server) AddAlwaysOnClient(account ClientAccount, chnames []string,
 
 		alwaysOn: true,
 		realname: realname,
+
+		nextSessionID: 1,
 	}
 
 	client.SetMode(modes.TLS, true)

irc/getters.go

@@ -65,12 +65,13 @@ func (client *Client) GetSessionByResumeID(resumeID string) (result *Session) {
 }
 
 type SessionData struct {
-	ctime    time.Time
-	atime    time.Time
-	ip       net.IP
-	hostname string
-	certfp   string
-	deviceID string
+	ctime     time.Time
+	atime     time.Time
+	ip        net.IP
+	hostname  string
+	certfp    string
+	deviceID  string
+	sessionID int64
 }
 
 func (client *Client) AllSessionData(currentSession *Session) (data []SessionData, currentIndex int) {
@@ -84,11 +85,12 @@ func (client *Client) AllSessionData(currentSession *Session) (data []SessionDat
 			currentIndex = i
 		}
 		data[i] = SessionData{
-			atime:    session.lastActive,
-			ctime:    session.ctime,
-			hostname: session.rawHostname,
-			certfp:   session.certfp,
-			deviceID: session.deviceID,
+			atime:     session.lastActive,
+			ctime:     session.ctime,
+			hostname:  session.rawHostname,
+			certfp:    session.certfp,
+			deviceID:  session.deviceID,
+			sessionID: session.sessionID,
 		}
 		if session.proxiedIP != nil {
 			data[i].ip = session.proxiedIP
@@ -109,6 +111,8 @@ func (client *Client) AddSession(session *Session) (success bool, numSessions in
 	}
 	// success, attach the new session to the client
 	session.client = client
+	session.sessionID = client.nextSessionID
+	client.nextSessionID++
 	newSessions := make([]*Session, len(client.sessions)+1)
 	copy(newSessions, client.sessions)
 	newSessions[len(newSessions)-1] = session

irc/nickserv.go

@@ -43,6 +43,23 @@ const nickservHelp = `NickServ lets you register, log in to, and manage an accou
 
 var (
 	nickservCommands = map[string]*serviceCommand{
+		"clients": {
+			handler: nsClientsHandler,
+			help: `Syntax: $bCLIENTS LIST [nickname]$b
+
+CLIENTS LIST shows information about the clients currently attached, via
+the server's multiclient functionality, to your nickname. An administrator
+can use this command to list another user's clients.
+
+Syntax: $bCLIENTS LOGOUT [nickname] [client_id/all]$b
+
+CLIENTS LOGOUT detaches a single client, or all other clients currently
+attached, via the server's multiclient functionality, to your nickname. An
+administrator can use this command to logout another user's clients.`,
+			helpShort: `$bCLIENTS$b can list and logout the sessions attached to a nickname.`,
+			enabled:   servCmdRequiresBouncerEnabled,
+			minParams: 1,
+		},
 		"drop": {
 			handler: nsDropHandler,
 			help: `Syntax: $bDROP [nickname]$b
@@ -150,14 +167,13 @@ an administrator can set use this command to set up user accounts.`,
 			minParams: 1,
 		},
 		"sessions": {
-			handler: nsSessionsHandler,
+			hidden:  true,
+			handler: nsClientsHandler,
 			help: `Syntax: $bSESSIONS [nickname]$b
 
-SESSIONS lists information about the sessions currently attached, via
-the server's multiclient functionality, to your nickname. An administrator
-can use this command to list another user's sessions.`,
-			helpShort: `$bSESSIONS$b lists the sessions attached to a nickname.`,
-			enabled:   servCmdRequiresBouncerEnabled,
+SESSIONS is an alias for $bCLIENTS LIST$b. See the help entry for $bCLIENTS$b
+for more information.`,
+			enabled: servCmdRequiresBouncerEnabled,
 		},
 		"unregister": {
 			handler: nsUnregisterHandler,
@@ -1065,9 +1081,30 @@ func nsEnforceHandler(server *Server, client *Client, command string, params []s
 	}
 }
 
-func nsSessionsHandler(server *Server, client *Client, command string, params []string, rb *ResponseBuffer) {
-	target := client
+func nsClientsHandler(server *Server, client *Client, command string, params []string, rb *ResponseBuffer) {
+	var verb string
 
+	if command == "sessions" {
+		// Legacy "SESSIONS" command is an alias for CLIENTS LIST.
+		verb = "list"
+	} else if len(params) > 0 {
+		verb = strings.ToLower(params[0])
+		params = params[1:]
+	}
+
+	switch verb {
+	case "list":
+		nsClientsListHandler(server, client, params, rb)
+	case "logout":
+		nsClientsLogoutHandler(server, client, params, rb)
+	default:
+		nsNotice(rb, client.t("Invalid parameters"))
+		return
+	}
+}
+
+func nsClientsListHandler(server *Server, client *Client, params []string, rb *ResponseBuffer) {
+	target := client
 	if 0 < len(params) {
 		target = server.clients.Get(params[0])
 		if target == nil {
@@ -1082,12 +1119,12 @@ func nsSessionsHandler(server *Server, client *Client, command string, params []
 	}
 
 	sessionData, currentIndex := target.AllSessionData(rb.session)
-	nsNotice(rb, fmt.Sprintf(client.t("Nickname %[1]s has %[2]d attached session(s)"), target.Nick(), len(sessionData)))
+	nsNotice(rb, fmt.Sprintf(client.t("Nickname %[1]s has %[2]d attached clients(s)"), target.Nick(), len(sessionData)))
 	for i, session := range sessionData {
 		if currentIndex == i {
-			nsNotice(rb, fmt.Sprintf(client.t("Session %d (currently attached session):"), i+1))
+			nsNotice(rb, fmt.Sprintf(client.t("Client %d (currently attached client):"), session.sessionID))
 		} else {
-			nsNotice(rb, fmt.Sprintf(client.t("Session %d:"), i+1))
+			nsNotice(rb, fmt.Sprintf(client.t("Client %d:"), session.sessionID))
 		}
 		if session.deviceID != "" {
 			nsNotice(rb, fmt.Sprintf(client.t("Device ID:   %s"), session.deviceID))
@@ -1102,6 +1139,61 @@ func nsSessionsHandler(server *Server, client *Client, command string, params []
 	}
 }
 
+func nsClientsLogoutHandler(server *Server, client *Client, params []string, rb *ResponseBuffer) {
+	if len(params) < 1 {
+		nsNotice(rb, client.t("Missing client ID to logout (or \"all\")"))
+		return
+	}
+
+	target := client
+	if len(params) >= 2 {
+		// CLIENTS LOGOUT [nickname] [client ID]
+		target = server.clients.Get(params[0])
+		if target == nil {
+			nsNotice(rb, client.t("No such nick"))
+			return
+		}
+		// User must have "local_kill" privileges to logout other user sessions.
+		if target != client {
+			oper := client.Oper()
+			if oper == nil || !oper.Class.Capabilities.Has("local_kill") {
+				nsNotice(rb, client.t("Insufficient oper privs"))
+				return
+			}
+		}
+		params = params[1:]
+	}
+
+	var sessionToDestroy *Session // target.destroy(nil) will logout all sessions
+	if strings.ToLower(params[0]) != "all" {
+		sessionID, err := strconv.ParseInt(params[0], 10, 64)
+		if err != nil {
+			nsNotice(rb, client.t("Client ID to logout should be an integer (or \"all\")"))
+			return
+		}
+		// Find the client ID that the user requested to logout.
+		sessions := target.Sessions()
+		for _, session := range sessions {
+			if session.sessionID == sessionID {
+				sessionToDestroy = session
+			}
+		}
+		if sessionToDestroy == nil {
+			nsNotice(rb, client.t("Specified client ID does not exist"))
+			return
+		}
+	}
+
+	target.destroy(sessionToDestroy)
+	if (sessionToDestroy != nil && rb.session != sessionToDestroy) || client != target {
+		if sessionToDestroy != nil {
+			nsNotice(rb, client.t("Successfully logged out session"))
+		} else {
+			nsNotice(rb, client.t("Successfully logged out all sessions"))
+		}
+	}
+}
+
 func nsCertHandler(server *Server, client *Client, command string, params []string, rb *ResponseBuffer) {
 	verb := strings.ToLower(params[0])
 	params = params[1:]