initial UBAN implementation

irc/chanserv.go

@@ -175,6 +175,17 @@ SET modifies a channel's settings. The following settings are available:`,
 			enabled:   chanregEnabled,
 			minParams: 3,
 		},
+		"howtoban": {
+			handler:   csHowToBanHandler,
+			helpShort: `$bHOWTOBAN$b suggests the best available way of banning a user`,
+			help: `Syntax: $bHOWTOBAN #channel <nick>
+
+The best way to ban a user from a channel will depend on how they are
+connected to the server. $bHOWTOBAN$b suggests a ban command that will
+(ideally) prevent the user from returning to the channel.`,
+			enabled:   chanregEnabled,
+			minParams: 2,
+		},
 	}
 )
 
@@ -809,3 +820,83 @@ func csSetHandler(service *ircService, server *Server, client *Client, command s
 		service.Notice(rb, client.t("An error occurred"))
 	}
 }
+
+func csHowToBanHandler(service *ircService, server *Server, client *Client, command string, params []string, rb *ResponseBuffer) {
+	success := false
+	defer func() {
+		if success {
+			service.Notice(rb, client.t("Note that if the user is currently in the channel, you must /KICK them after you ban them"))
+		}
+	}()
+
+	chname, nick := params[0], params[1]
+	channel := server.channels.Get(chname)
+	if channel == nil {
+		service.Notice(rb, client.t("No such channel"))
+		return
+	}
+
+	if !channel.ClientIsAtLeast(client, modes.Operator) || client.HasRoleCapabs("samode") {
+		service.Notice(rb, client.t("Insufficient privileges"))
+		return
+	}
+
+	var details WhoWas
+	target := server.clients.Get(nick)
+	if target == nil {
+		whowasList := server.whoWas.Find(nick, 1)
+		if len(whowasList) == 0 {
+			service.Notice(rb, client.t("No such nick"))
+			return
+		}
+		service.Notice(rb, fmt.Sprintf(client.t("Warning: %s is not currently connected to the server. Using WHOWAS data, which may be inaccurate:"), nick))
+		details = whowasList[0]
+	} else {
+		details = target.Details().WhoWas
+	}
+
+	if details.account != "" {
+		if channel.getAmode(details.account) != modes.Mode(0) {
+			service.Notice(rb, fmt.Sprintf(client.t("Warning: account %s currently has a persistent channel privilege granted with CS AMODE. If this mode is not removed, bans will not be respected"), details.accountName))
+			return
+		} else if details.account == channel.Founder() {
+			service.Notice(rb, fmt.Sprintf(client.t("Warning: account %s is the channel founder and cannot be banned"), details.accountName))
+			return
+		}
+	}
+
+	config := server.Config()
+	if !config.Server.Cloaks.EnabledForAlwaysOn {
+		service.Notice(rb, client.t("Warning: server.ip-cloaking.enabled-for-always-on is disabled. This reduces the precision of channel bans."))
+	}
+
+	if details.account != "" {
+		if config.Accounts.NickReservation.ForceNickEqualsAccount || target.AlwaysOn() {
+			service.Notice(rb, fmt.Sprintf(client.t("User %[1]s is authenticated and can be banned by nickname: /MODE %[2]s +b %[3]s!*@*"), details.nick, channel.Name(), details.nick))
+			success = true
+			return
+		}
+	}
+
+	ban := fmt.Sprintf("*!*@%s", strings.ToLower(details.hostname))
+	banRe, err := utils.CompileGlob(ban, false)
+	if err != nil {
+		server.logger.Error("internal", "couldn't compile ban regex", ban, err.Error())
+		service.Notice(rb, "An error occurred")
+		return
+	}
+	var collateralDamage []string
+	for _, mcl := range channel.Members() {
+		if mcl != target && banRe.MatchString(mcl.NickMaskCasefolded()) {
+			collateralDamage = append(collateralDamage, mcl.Nick())
+		}
+	}
+	service.Notice(rb, fmt.Sprintf(client.t("User %[1]s can be banned by hostname: /MODE %[2]s +b %[3]s"), details.nick, channel.Name(), ban))
+	success = true
+	if len(collateralDamage) != 0 {
+		service.Notice(rb, fmt.Sprintf(client.t("Warning: this ban will affect %d other users:"), len(collateralDamage)))
+		for _, line := range utils.BuildTokenLines(400, collateralDamage, " ") {
+			service.Notice(rb, line)
+		}
+	}
+}

irc/client.go

@@ -292,6 +292,9 @@ type WhoWas struct {
 	username       string
 	hostname       string
 	realname       string
+	// technically not required for WHOWAS:
+	account     string
+	accountName string
 }
 
 // ClientDetails is a standard set of details about a client
@@ -300,8 +303,6 @@ type ClientDetails struct {
 
 	nickMask           string
 	nickMaskCasefolded string
-	account            string
-	accountName        string
 }
 
 // RunClient sets up a new client and runs its goroutine.

irc/commands.go

@@ -319,6 +319,11 @@ func init() {
 			handler:   topicHandler,
 			minParams: 1,
 		},
+		"UBAN": {
+			handler:   ubanHandler,
+			minParams: 1,
+			capabs:    []string{"ban"},
+		},
 		"UNDLINE": {
 			handler:   unDLineHandler,
 			minParams: 1,

irc/connection_limits/limiter.go

@@ -209,6 +209,38 @@ func (cl *Limiter) RemoveClient(addr flatip.IP) {
 	cl.limiter[addrString] = count
 }
 
+type LimiterStatus struct {
+	Exempt bool
+
+	Count    int
+	MaxCount int
+
+	Throttle         int
+	MaxPerWindow     int
+	ThrottleDuration time.Duration
+}
+
+func (cl *Limiter) Status(addr flatip.IP) (status LimiterStatus) {
+	cl.Lock()
+	defer cl.Unlock()
+
+	if flatip.IPInNets(addr, cl.config.exemptedNets) {
+		status.Exempt = true
+		return
+	}
+
+	status.ThrottleDuration = cl.config.Window
+
+	addrString, maxConcurrent, maxPerWindow := cl.addrToKey(addr)
+	status.MaxCount = maxConcurrent
+	status.MaxPerWindow = maxPerWindow
+
+	status.Count = cl.limiter[addrString]
+	status.Throttle = cl.throttler[addrString].Count
+
+	return
+}
+
 // ResetThrottle resets the throttle count for an IP
 func (cl *Limiter) ResetThrottle(addr flatip.IP) {
 	cl.Lock()

irc/dline.go

@@ -6,13 +6,11 @@ package irc
 import (
 	"encoding/json"
 	"fmt"
-	"net"
 	"strings"
 	"sync"
 	"time"
 
 	"github.com/oragono/oragono/irc/flatip"
-	"github.com/oragono/oragono/irc/utils"
 	"github.com/tidwall/buntdb"
 )
 
@@ -48,7 +46,11 @@ func (info IPBanInfo) TimeLeft() string {
 
 // BanMessage returns the ban message.
 func (info IPBanInfo) BanMessage(message string) string {
-	message = fmt.Sprintf(message, info.Reason)
+	reason := info.Reason
+	if reason == "" {
+		reason = "No reason given"
+	}
+	message = fmt.Sprintf(message, reason)
 	if info.Duration != 0 {
 		message += fmt.Sprintf(" [%s]", info.TimeLeft())
 	}
@@ -86,14 +88,14 @@ func (dm *DLineManager) AllBans() map[string]IPBanInfo {
 	defer dm.RUnlock()
 
 	for key, info := range dm.networks {
-		allb[key.String()] = info
+		allb[key.HumanReadableString()] = info
 	}
 
 	return allb
 }
 
 // AddNetwork adds a network to the blocked list.
-func (dm *DLineManager) AddNetwork(network net.IPNet, duration time.Duration, reason, operReason, operName string) error {
+func (dm *DLineManager) AddNetwork(network flatip.IPNet, duration time.Duration, reason, operReason, operName string) error {
 	dm.persistenceMutex.Lock()
 	defer dm.persistenceMutex.Unlock()
 
@@ -110,8 +112,7 @@ func (dm *DLineManager) AddNetwork(network net.IPNet, duration time.Duration, re
 	return dm.persistDline(id, info)
 }
 
-func (dm *DLineManager) addNetworkInternal(network net.IPNet, info IPBanInfo) (id flatip.IPNet) {
-	flatnet := flatip.FromNetIPNet(network)
+func (dm *DLineManager) addNetworkInternal(flatnet flatip.IPNet, info IPBanInfo) (id flatip.IPNet) {
 	id = flatnet
 
 	var timeLeft time.Duration
@@ -193,11 +194,11 @@ func (dm *DLineManager) unpersistDline(id flatip.IPNet) error {
 }
 
 // RemoveNetwork removes a network from the blocked list.
-func (dm *DLineManager) RemoveNetwork(network net.IPNet) error {
+func (dm *DLineManager) RemoveNetwork(network flatip.IPNet) error {
 	dm.persistenceMutex.Lock()
 	defer dm.persistenceMutex.Unlock()
 
-	id := flatip.FromNetIPNet(network)
+	id := network
 
 	present := func() bool {
 		dm.Lock()
@@ -215,22 +216,8 @@ func (dm *DLineManager) RemoveNetwork(network net.IPNet) error {
 	return dm.unpersistDline(id)
 }
 
-// AddIP adds an IP address to the blocked list.
-func (dm *DLineManager) AddIP(addr net.IP, duration time.Duration, reason, operReason, operName string) error {
-	return dm.AddNetwork(utils.NormalizeIPToNet(addr), duration, reason, operReason, operName)
-}
-
-// RemoveIP removes an IP address from the blocked list.
-func (dm *DLineManager) RemoveIP(addr net.IP) error {
-	return dm.RemoveNetwork(utils.NormalizeIPToNet(addr))
-}
-
 // CheckIP returns whether or not an IP address was banned, and how long it is banned for.
 func (dm *DLineManager) CheckIP(addr flatip.IP) (isBanned bool, info IPBanInfo) {
-	if addr.IsLoopback() {
-		return // #671
-	}
-
 	dm.RLock()
 	defer dm.RUnlock()
 
@@ -257,7 +244,7 @@ func (dm *DLineManager) loadFromDatastore() {
 			key = strings.TrimPrefix(key, dlinePrefix)
 
 			// load addr/net
-			hostNet, err := utils.NormalizedNetFromString(key)
+			hostNet, err := flatip.ParseToNormalizedNet(key)
 			if err != nil {
 				dm.server.logger.Error("internal", "bad dline cidr", err.Error())
 				return true

irc/flatip/flatip.go

@@ -183,6 +183,16 @@ func (cidr IPNet) String() string {
 	return ipnet.String()
 }
 
+// HumanReadableString returns a string representation of an IPNet;
+// if the network contains only a single IP address, it returns
+// a representation of that address.
+func (cidr IPNet) HumanReadableString() string {
+	if cidr.PrefixLen == 128 {
+		return cidr.IP.String()
+	}
+	return cidr.String()
+}
+
 // IsZero tests whether ipnet is the zero value of an IPNet, 0::0/0.
 // Although this is a valid subnet, it can still be used as a sentinel
 // value in some contexts.

irc/getters.go

@@ -314,6 +314,12 @@ func (client *Client) setCloakedHostname(cloak string) {
 	client.updateNickMaskNoMutex()
 }
 
+func (client *Client) CloakedHostname() string {
+	client.stateMutex.Lock()
+	defer client.stateMutex.Unlock()
+	return client.cloakedHostname
+}
+
 func (client *Client) historyCutoff() (cutoff time.Time) {
 	client.stateMutex.Lock()
 	if client.account != "" {
@@ -553,3 +559,9 @@ func (channel *Channel) Ctime() (ctime time.Time) {
 	channel.stateMutex.RUnlock()
 	return
 }
+
+func (channel *Channel) getAmode(cfaccount string) (result modes.Mode) {
+	channel.stateMutex.RLock()
+	defer channel.stateMutex.RUnlock()
+	return channel.accountToUMode[cfaccount]
+}

irc/handlers.go

@@ -906,7 +906,7 @@ func dlineHandler(server *Server, client *Client, msg ircmsg.IrcMessage, rb *Res
 		operName = server.name
 	}
 
-	err = server.dlines.AddNetwork(hostNet, duration, reason, operReason, operName)
+	err = server.dlines.AddNetwork(flatip.FromNetIPNet(hostNet), duration, reason, operReason, operName)
 
 	if err != nil {
 		rb.Notice(fmt.Sprintf(client.t("Could not successfully save new D-LINE: %s"), err.Error()))
@@ -2833,13 +2833,8 @@ func unDLineHandler(server *Server, client *Client, msg ircmsg.IrcMessage, rb *R
 	// get host
 	hostString := msg.Params[0]
 
-	// TODO(#1447) consolidate this into the "unban" command
-	if flatip, ipErr := flatip.ParseIP(hostString); ipErr == nil {
-		server.connectionLimiter.ResetThrottle(flatip)
-	}
-
 	// check host
-	hostNet, err := utils.NormalizedNetFromString(hostString)
+	hostNet, err := flatip.ParseToNormalizedNet(hostString)
 
 	if err != nil {
 		rb.Add(nil, server.name, ERR_UNKNOWNERROR, client.nick, msg.Command, client.t("Could not parse IP address or CIDR network"))
@@ -2853,7 +2848,7 @@ func unDLineHandler(server *Server, client *Client, msg ircmsg.IrcMessage, rb *R
 		return false
 	}
 
-	hostString = utils.NetToNormalizedString(hostNet)
+	hostString = hostNet.String()
 	rb.Notice(fmt.Sprintf(client.t("Removed D-Line for %s"), hostString))
 	server.snomasks.Send(sno.LocalXline, fmt.Sprintf(ircfmt.Unescape("%s$r removed D-Line for %s"), client.nick, hostString))
 	return false

irc/help.go

@@ -520,6 +520,19 @@ Shows the time of the current, or the given, server.`,
 
 If [topic] is given, sets the topic in the channel to that. If [topic] is not
 given, views the current topic on the channel.`,
+	},
+	"uban": {
+		text: `UBAN <subcommand> [arguments]
+
+Oragono's "unified ban" system. Accepts the following subcommands:
+
+1. UBAN ADD <target> [DURATION <duration>] [REASON...]
+2. UBAN DEL <target>
+3. UBAN LIST
+4. UBAN INFO <target>
+
+<target> may be an IP, a CIDR, a nickmask with wildcards, or the name of an
+account to suspend.`,
 	},
 	"undline": {
 		oper: true,

irc/ircconn.go

@@ -1,3 +1,6 @@
+// Copyright (c) 2020 Shivaram Lingamneni
+// released under the MIT license
+
 package irc
 
 import (

irc/kline.go

@@ -189,6 +189,17 @@ func (km *KLineManager) RemoveMask(mask string) error {
 	return km.unpersistKLine(mask)
 }
 
+func (km *KLineManager) ContainsMask(mask string) (isBanned bool, info IPBanInfo) {
+	km.RLock()
+	defer km.RUnlock()
+
+	klineInfo, isBanned := km.entries[mask]
+	if isBanned {
+		info = klineInfo.Info
+	}
+	return
+}
+
 // CheckMasks returns whether or not the hostmask(s) are banned, and how long they are banned for.
 func (km *KLineManager) CheckMasks(masks ...string) (isBanned bool, info IPBanInfo) {
 	km.RLock()

irc/nickserv.go

@@ -1361,11 +1361,16 @@ func (a ByCreationTime) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
 func (a ByCreationTime) Less(i, j int) bool { return a[i].TimeCreated.After(a[j].TimeCreated) }
 
 func nsSuspendListHandler(service *ircService, server *Server, client *Client, command string, params []string, rb *ResponseBuffer) {
-	suspensions := server.accounts.ListSuspended()
+	listAccountSuspensions(client, rb, service.prefix)
+}
+
+func listAccountSuspensions(client *Client, rb *ResponseBuffer, source string) {
+	suspensions := client.server.accounts.ListSuspended()
 	sort.Sort(ByCreationTime(suspensions))
-	service.Notice(rb, fmt.Sprintf(client.t("There are %d active suspensions."), len(suspensions)))
+	nick := client.Nick()
+	rb.Add(nil, source, "NOTICE", nick, fmt.Sprintf(client.t("There are %d active account suspensions."), len(suspensions)))
 	for _, suspension := range suspensions {
-		service.Notice(rb, suspensionToString(client, suspension))
+		rb.Add(nil, source, "NOTICE", nick, suspensionToString(client, suspension))
 	}
 }
 

irc/server.go

@@ -162,8 +162,14 @@ func (server *Server) Run() {
 }
 
 func (server *Server) checkBans(config *Config, ipaddr net.IP, checkScripts bool) (banned bool, requireSASL bool, message string) {
+	// #671: do not enforce bans against loopback, as a failsafe
+	// note that this function is not used for Tor connections (checkTorLimits is used instead)
+	if ipaddr.IsLoopback() {
+		return
+	}
+
 	if server.Defcon() == 1 {
-		if !(ipaddr.IsLoopback() || utils.IPInNets(ipaddr, server.Config().Server.secureNets)) {
+		if !utils.IPInNets(ipaddr, server.Config().Server.secureNets) {
 			return true, false, "New connections to this server are temporarily restricted"
 		}
 	}
@@ -198,7 +204,7 @@ func (server *Server) checkBans(config *Config, ipaddr net.IP, checkScripts bool
 		}
 		// TODO: currently no way to cache results other than IPBanned
 		if output.Result == IPBanned && output.CacheSeconds != 0 {
-			network, err := utils.NormalizedNetFromString(output.CacheNet)
+			network, err := flatip.ParseToNormalizedNet(output.CacheNet)
 			if err != nil {
 				server.logger.Error("internal", "invalid dline net from IP ban script", ipaddr.String(), output.CacheNet)
 			} else {
@@ -339,12 +345,14 @@ func (server *Server) tryRegister(c *Client, session *Session) (exiting bool) {
 	// count new user in statistics (before checking KLINEs, see #1303)
 	server.stats.Register(c.HasMode(modes.Invisible))
 
-	// check KLINEs
+	// check KLINEs (#671: ignore KLINEs for loopback connections)
+	if !session.IP().IsLoopback() || session.isTor {
 		isBanned, info := server.klines.CheckMasks(c.AllNickmasks()...)
 		if isBanned {
 			c.Quit(info.BanMessage(c.t("You are banned from this server (%s)")), nil)
 			return true
 		}
+	}
 
 	server.playRegistrationBurst(session)
 	return false

irc/uban.go

@@ -0,0 +1,381 @@
+// Copyright (c) 2021 Shivaram Lingamneni
+// released under the MIT license
+
+package irc
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+	"time"
+
+	"github.com/goshuirc/irc-go/ircmsg"
+
+	"github.com/oragono/oragono/irc/custime"
+	"github.com/oragono/oragono/irc/flatip"
+	"github.com/oragono/oragono/irc/utils"
+)
+
+func consumeDuration(params []string, rb *ResponseBuffer) (duration time.Duration, remainingParams []string, err error) {
+	remainingParams = params
+	if 2 <= len(remainingParams) && strings.ToLower(remainingParams[0]) == "duration" {
+		duration, err = custime.ParseDuration(remainingParams[1])
+		if err != nil {
+			rb.Notice(rb.session.client.t("Invalid time duration for NS SUSPEND"))
+			return
+		}
+		remainingParams = remainingParams[2:]
+	}
+	return
+}
+
+// a UBAN target is one of these syntactically unambiguous entities:
+// an IP, a CIDR, a NUH mask, or an account name
+type ubanType uint
+
+const (
+	ubanCIDR ubanType = iota
+	ubanNickmask
+	ubanNick
+)
+
+// tagged union, i guess
+type ubanTarget struct {
+	banType ubanType
+
+	cidr       flatip.IPNet
+	matcher    *regexp.Regexp
+	nickOrMask string
+}
+
+func parseUbanTarget(param string) (target ubanTarget, err error) {
+	if utils.SafeErrorParam(param) == "*" {
+		err = errInvalidParams
+		return
+	}
+
+	ipnet, ipErr := flatip.ParseToNormalizedNet(param)
+	if ipErr == nil {
+		target.banType = ubanCIDR
+		target.cidr = ipnet
+		return
+	}
+
+	if strings.IndexByte(param, '!') != -1 || strings.IndexByte(param, '@') != -1 {
+		canonicalized, cErr := CanonicalizeMaskWildcard(param)
+		if cErr != nil {
+			err = errInvalidParams
+			return
+		}
+		re, reErr := utils.CompileGlob(canonicalized, false)
+		if reErr != nil {
+			err = errInvalidParams
+			return
+		}
+		target.banType = ubanNickmask
+		target.nickOrMask = canonicalized
+		target.matcher = re
+		return
+	}
+
+	if _, cErr := CasefoldName(param); cErr == nil {
+		target.banType = ubanNick
+		target.nickOrMask = param
+		return
+	}
+
+	err = errInvalidParams
+	return
+}
+
+// UBAN <subcommand> [target] [DURATION <duration>] [reason...]
+func ubanHandler(server *Server, client *Client, msg ircmsg.IrcMessage, rb *ResponseBuffer) bool {
+	subcommand := strings.ToLower(msg.Params[0])
+	params := msg.Params[1:]
+	var target ubanTarget
+	if subcommand != "list" {
+		if len(msg.Params) == 1 {
+			rb.Add(nil, client.server.name, "FAIL", "UBAN", "INVALID_PARAMS", client.t("Not enough parameters"))
+			return false
+		}
+		var parseErr error
+		target, parseErr = parseUbanTarget(params[0])
+		if parseErr != nil {
+			rb.Add(nil, client.server.name, "FAIL", "UBAN", "INVALID_PARAMS", client.t("Couldn't parse ban target"))
+			return false
+		}
+		params = params[1:]
+	}
+
+	switch subcommand {
+	case "add":
+		return ubanAddHandler(client, target, params, rb)
+	case "del", "remove", "rm":
+		return ubanDelHandler(client, target, params, rb)
+	case "list":
+		return ubanListHandler(client, params, rb)
+	case "info":
+		return ubanInfoHandler(client, target, params, rb)
+	default:
+		rb.Add(nil, server.name, "FAIL", "UBAN", "UNKNOWN_COMMAND", client.t("Unknown command"))
+		return false
+	}
+}
+
+func sessionsForCIDR(server *Server, cidr flatip.IPNet, exclude *Session) (sessions []*Session, nicks []string) {
+	for _, client := range server.clients.AllClients() {
+		for _, session := range client.Sessions() {
+			seen := false
+			if session != exclude && cidr.Contains(flatip.FromNetIP(session.IP())) {
+				sessions = append(sessions, session)
+				if !seen {
+					seen = true
+					nicks = append(nicks, session.client.Nick())
+				}
+			}
+		}
+	}
+	return
+}
+
+func ubanAddHandler(client *Client, target ubanTarget, params []string, rb *ResponseBuffer) bool {
+	duration, params, err := consumeDuration(params, rb)
+	if err != nil {
+		return false
+	}
+
+	operReason := strings.Join(params, " ")
+
+	switch target.banType {
+	case ubanCIDR:
+		ubanAddCIDR(client, target, duration, operReason, rb)
+	case ubanNickmask:
+		ubanAddNickmask(client, target, duration, operReason, rb)
+	case ubanNick:
+		account := target.nickOrMask
+		err := client.server.accounts.Suspend(account, duration, client.Oper().Name, "UBAN")
+		switch err {
+		case nil:
+			rb.Notice(fmt.Sprintf(client.t("Successfully suspended account %s"), account))
+		case errAccountDoesNotExist:
+			rb.Notice(client.t("No such account"))
+		default:
+			rb.Notice(client.t("An error occurred"))
+		}
+	}
+	return false
+}
+
+func ubanAddCIDR(client *Client, target ubanTarget, duration time.Duration, operReason string, rb *ResponseBuffer) {
+	err := client.server.dlines.AddNetwork(target.cidr, duration, "", operReason, client.Oper().Name)
+	if err == nil {
+		rb.Notice(fmt.Sprintf(client.t("Successfully added UBAN for %s"), target.cidr.HumanReadableString()))
+	} else {
+		client.server.logger.Error("internal", "ubanAddCIDR failed", err.Error())
+		rb.Notice(client.t("An error occurred"))
+		return
+	}
+
+	sessions, nicks := sessionsForCIDR(client.server, target.cidr, rb.session)
+	for _, session := range sessions {
+		session.client.Quit("You have been banned from this server", session)
+		session.client.destroy(session)
+	}
+
+	if len(sessions) != 0 {
+		rb.Notice(fmt.Sprintf(client.t("Killed %[1]d active client(s) from %[2]s, associated with %[3]d nickname(s):"), len(sessions), target.cidr.String(), len(nicks)))
+		for _, line := range utils.BuildTokenLines(400, nicks, " ") {
+			rb.Notice(line)
+		}
+	}
+}
+
+func ubanAddNickmask(client *Client, target ubanTarget, duration time.Duration, operReason string, rb *ResponseBuffer) {
+	err := client.server.klines.AddMask(target.nickOrMask, duration, "", operReason, client.Oper().Name)
+	if err == nil {
+		rb.Notice(fmt.Sprintf(client.t("Successfully added UBAN for %s"), target.nickOrMask))
+	} else {
+		client.server.logger.Error("internal", "ubanAddNickmask failed", err.Error())
+		rb.Notice(client.t("An error occurred"))
+		return
+	}
+
+	var killed []string
+	var alwaysOn []string
+	for _, mcl := range client.server.clients.AllClients() {
+		if mcl != client && target.matcher.MatchString(client.NickMaskCasefolded()) {
+			if !mcl.AlwaysOn() {
+				killed = append(killed, mcl.Nick())
+				mcl.destroy(nil)
+			} else {
+				alwaysOn = append(alwaysOn, mcl.Nick())
+			}
+		}
+	}
+	if len(killed) != 0 {
+		rb.Notice(fmt.Sprintf(client.t("Killed %d clients:"), len(killed)))
+		for _, line := range utils.BuildTokenLines(400, killed, " ") {
+			rb.Notice(line)
+		}
+	}
+	if len(alwaysOn) != 0 {
+		rb.Notice(fmt.Sprintf(client.t("Warning: %d clients matched this rule, but were not killed due to being always-on:"), len(alwaysOn)))
+		for _, line := range utils.BuildTokenLines(400, alwaysOn, " ") {
+			rb.Notice(line)
+		}
+		rb.Notice(client.t("You can suspend their accounts instead; try /UBAN ADD <nickname>"))
+	}
+}
+
+func ubanDelHandler(client *Client, target ubanTarget, params []string, rb *ResponseBuffer) bool {
+	var err error
+	var targetString string
+	switch target.banType {
+	case ubanCIDR:
+		if target.cidr.PrefixLen == 128 {
+			client.server.connectionLimiter.ResetThrottle(target.cidr.IP)
+			rb.Notice(fmt.Sprintf(client.t("Reset throttle for IP: %s"), target.cidr.IP.String()))
+		}
+		targetString = target.cidr.HumanReadableString()
+		err = client.server.dlines.RemoveNetwork(target.cidr)
+	case ubanNickmask:
+		targetString = target.nickOrMask
+		err = client.server.klines.RemoveMask(target.nickOrMask)
+	case ubanNick:
+		targetString = target.nickOrMask
+		err = client.server.accounts.Unsuspend(target.nickOrMask)
+	}
+	if err == nil {
+		rb.Notice(fmt.Sprintf(client.t("Successfully removed ban on %s"), targetString))
+	} else {
+		rb.Notice(fmt.Sprintf(client.t("Could not remove ban: %v"), err))
+	}
+	return false
+}
+
+func ubanListHandler(client *Client, params []string, rb *ResponseBuffer) bool {
+	allDlines := client.server.dlines.AllBans()
+	rb.Notice(fmt.Sprintf(client.t("There are %d active IP/network ban(s) (DLINEs)"), len(allDlines)))
+	for key, info := range allDlines {
+		rb.Notice(formatBanForListing(client, key, info))
+	}
+	rb.Notice(client.t("Some IPs may also be prevented from connecting by the connection limiter and/or throttler"))
+
+	allKlines := client.server.klines.AllBans()
+	rb.Notice(fmt.Sprintf(client.t("There are %d active ban(s) on nick-user-host masks (KLINEs)"), len(allKlines)))
+	for key, info := range allKlines {
+		rb.Notice(formatBanForListing(client, key, info))
+	}
+
+	listAccountSuspensions(client, rb, client.server.name)
+
+	return false
+}
+
+func ubanInfoHandler(client *Client, target ubanTarget, params []string, rb *ResponseBuffer) bool {
+	switch target.banType {
+	case ubanCIDR:
+		ubanInfoCIDR(client, target, rb)
+	case ubanNickmask:
+		ubanInfoNickmask(client, target, rb)
+	case ubanNick:
+		ubanInfoNick(client, target, rb)
+	}
+	return false
+}
+
+func ubanInfoCIDR(client *Client, target ubanTarget, rb *ResponseBuffer) {
+	if target.cidr.PrefixLen == 128 {
+		status := client.server.connectionLimiter.Status(target.cidr.IP)
+		str := target.cidr.IP.String()
+		if status.Exempt {
+			rb.Notice(fmt.Sprintf(client.t("IP %s is exempt from connection limits"), str))
+		} else {
+			rb.Notice(fmt.Sprintf(client.t("IP %[1]s has %[2]d active connections out of a maximum of %[3]d"), str, status.Count, status.MaxCount))
+			rb.Notice(fmt.Sprintf(client.t("IP %[1]s has had %[2]d connection attempts in the past %[3]v, out of a maximum of %[4]d"), str, status.Throttle, status.ThrottleDuration, status.MaxPerWindow))
+		}
+	}
+
+	str := target.cidr.HumanReadableString()
+	isBanned, banInfo := client.server.dlines.CheckIP(target.cidr.IP)
+	if isBanned {
+		rb.Notice(formatBanForListing(client, str, banInfo))
+	} else {
+		rb.Notice(fmt.Sprintf(client.t("There is no active IP ban against %s"), str))
+	}
+
+	sessions, nicks := sessionsForCIDR(client.server, target.cidr, nil)
+	if len(sessions) != 0 {
+		rb.Notice(fmt.Sprintf(client.t("There are %[1]d active client(s) from %[2]s, associated with %[3]d nickname(s):"), len(sessions), target.cidr.String(), len(nicks)))
+		for _, line := range utils.BuildTokenLines(400, nicks, " ") {
+			rb.Notice(line)
+		}
+	}
+}
+
+func ubanInfoNickmask(client *Client, target ubanTarget, rb *ResponseBuffer) {
+	isBanned, info := client.server.klines.ContainsMask(target.nickOrMask)
+	if isBanned {
+		rb.Notice(formatBanForListing(client, target.nickOrMask, info))
+	} else {
+		rb.Notice(fmt.Sprintf(client.t("No ban exists for %[1]s"), target.nickOrMask))
+	}
+
+	affectedCount := 0
+	alwaysOnCount := 0
+	for _, mcl := range client.server.clients.AllClients() {
+		matches := false
+		for _, mask := range mcl.AllNickmasks() {
+			if target.matcher.MatchString(mask) {
+				matches = true
+				break
+			}
+		}
+		if matches {
+			if mcl.AlwaysOn() {
+				alwaysOnCount++
+			} else {
+				affectedCount++
+			}
+		}
+	}
+
+	rb.Notice(fmt.Sprintf(client.t("Adding this mask would affect %[1]d clients (an additional %[2]d clients are exempt due to always-on)"), affectedCount, alwaysOnCount))
+}
+
+func ubanInfoNick(client *Client, target ubanTarget, rb *ResponseBuffer) {
+	mcl := client.server.clients.Get(target.nickOrMask)
+	if mcl != nil {
+		details := mcl.Details()
+		if details.account == "" {
+			rb.Notice(fmt.Sprintf(client.t("Client %[1]s is unauthenticated and connected from %[2]s"), details.nick, client.IP().String()))
+		} else {
+			rb.Notice(fmt.Sprintf(client.t("Client %[1]s is logged into account %[2]s and has %[3]d active clients (see /NICKSERV CLIENTS LIST %[4]s for more info"), details.nick, details.accountName, len(mcl.Sessions()), details.nick))
+			ip := client.IP()
+			if !ip.IsLoopback() {
+				rb.Notice(fmt.Sprintf(client.t("Client %[1]s is associated with IP %[2]s; you can ban this IP with /UBAN ADD"), details.nick, ip.String()))
+			}
+		}
+	} else {
+		rb.Notice(fmt.Sprintf(client.t("No client is currently using that nickname")))
+	}
+
+	account, err := client.server.accounts.LoadAccount(target.nickOrMask)
+	if err != nil {
+		if err == errAccountDoesNotExist {
+			rb.Notice(fmt.Sprintf(client.t("There is no account registered for %s"), target.nickOrMask))
+		} else {
+			rb.Notice(fmt.Sprintf(client.t("Couldn't load account: %v"), err.Error()))
+		}
+		return
+	}
+	if account.Verified {
+		if account.Suspended == nil {
+			rb.Notice(fmt.Sprintf(client.t("Account %[1]s is in good standing; see /NICKSERV INFO %[2]s for more details"), target.nickOrMask, target.nickOrMask))
+		} else {
+			rb.Notice(fmt.Sprintf(client.t("Account %[1]s has been suspended: %[2]s"), target.nickOrMask, suspensionToString(client, *account.Suspended)))
+		}
+	} else {
+		rb.Notice(fmt.Sprintf(client.t("Account %[1]s was created, but has not been verified"), target.nickOrMask))
+	}
+}