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xK/xS/xS.go

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//
// Copyright (c) 2014 - 2022, Přemysl Eric Janouch <p@janouch.name>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
//
// xS is a straight-forward port of xD IRCd from C.
package main
import (
"bufio"
"bytes"
"crypto/sha256"
"crypto/tls"
"encoding/hex"
"errors"
"flag"
"fmt"
"io"
"io/ioutil"
"log/syslog"
"net"
"os"
"os/signal"
"os/user"
"path/filepath"
"regexp"
"strconv"
"strings"
"syscall"
"time"
)
const projectName = "xS"
var projectVersion = "?"
var debugMode = false
// --- Logging -----------------------------------------------------------------
type logPrio int
const (
prioFatal logPrio = iota
prioError
prioWarning
prioStatus
prioDebug
)
func (lp logPrio) prefix() string {
switch lp {
case prioFatal:
return "fatal: "
case prioError:
return "error: "
case prioWarning:
return "warning: "
case prioStatus:
return ""
case prioDebug:
return "debug: "
default:
panic("unhandled log priority")
}
}
func (lp logPrio) syslogPrio() syslog.Priority {
switch lp {
case prioFatal:
return syslog.LOG_ERR
case prioError:
return syslog.LOG_ERR
case prioWarning:
return syslog.LOG_WARNING
case prioStatus:
return syslog.LOG_INFO
case prioDebug:
return syslog.LOG_DEBUG
default:
panic("unhandled log priority")
}
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
func logMessageStdio(prio logPrio, format string, args ...interface{}) {
// TODO: isatty-enabled colors based on prio.
os.Stderr.WriteString(time.Now().Format("2006-01-02 15:04:05 ") +
prio.prefix() + fmt.Sprintf(format, args...) + "\n")
}
func logMessageSystemd(prio logPrio, format string, args ...interface{}) {
if prio == prioFatal {
// There is no corresponding syslog severity.
format = "fatal: " + format
}
fmt.Fprintf(os.Stderr, "<%d>%s\n",
prio.syslogPrio(), fmt.Sprintf(format, args...))
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
var logMessage = logMessageStdio
func printDebug(format string, args ...interface{}) {
if debugMode {
logMessage(prioDebug, format, args...)
}
}
func printStatus(format string, args ...interface{}) {
logMessage(prioStatus, format, args...)
}
func printWarning(format string, args ...interface{}) {
logMessage(prioWarning, format, args...)
}
func printError(format string, args ...interface{}) {
logMessage(prioError, format, args...)
}
// "fatal" is reserved for failures that would harm further operation.
func printFatal(format string, args ...interface{}) {
logMessage(prioFatal, format, args...)
}
func exitFatal(format string, args ...interface{}) {
printFatal(format, args...)
os.Exit(1)
}
// --- Utilities ---------------------------------------------------------------
// Split a string by a set of UTF-8 delimiters, optionally ignoring empty items.
func splitString(s, delims string, ignoreEmpty bool) (result []string) {
for {
end := strings.IndexAny(s, delims)
if end < 0 {
break
}
if !ignoreEmpty || end != 0 {
result = append(result, s[:end])
}
s = s[end+1:]
}
if !ignoreEmpty || s != "" {
result = append(result, s)
}
return
}
// Trivial SSL/TLS autodetection. The first block of data returned by Recvfrom
// must be at least three octets long for this to work reliably, but that should
// not pose a problem in practice. We might try waiting for them.
//
// SSL2: 1xxx xxxx | xxxx xxxx | <1>
// (message length) (client hello)
// SSL3/TLS: <22> | <3> | xxxx xxxx
// (handshake)| (protocol version)
//
// Note that Go 1.12's crypto/tls offers a slightly more straight-forward
// solution: "If a client sends an initial message that does not look like TLS,
// the server will no longer reply with an alert, and it will expose the
// underlying net.Conn in the new field Conn of RecordHeaderError."
func detectTLS(sysconn syscall.RawConn) (isTLS bool) {
sysconn.Read(func(fd uintptr) (done bool) {
var buf [3]byte
n, _, err := syscall.Recvfrom(int(fd), buf[:], syscall.MSG_PEEK)
switch {
case n == 3:
isTLS = buf[0]&0x80 != 0 && buf[2] == 1
fallthrough
case n == 2:
isTLS = isTLS || buf[0] == 22 && buf[1] == 3
case n == 1:
isTLS = buf[0] == 22
case err == syscall.EAGAIN:
return false
}
return true
})
return isTLS
}
// --- File system -------------------------------------------------------------
// Look up the value of an XDG path from environment, or fall back to a default.
func getXDGHomeDir(name, def string) string {
env := os.Getenv(name)
if env != "" && env[0] == filepath.Separator {
return env
}
home := ""
if v, ok := os.LookupEnv("HOME"); ok {
home = v
} else if u, _ := user.Current(); u != nil {
home = u.HomeDir
}
return filepath.Join(home, def)
}
func resolveRelativeFilenameGeneric(paths []string, filename string) string {
for _, path := range paths {
// As per XDG spec, relative paths are ignored.
if path == "" || path[0] != filepath.Separator {
continue
}
file := filepath.Join(path, filename)
if _, err := os.Stat(file); err == nil {
return file
}
}
return ""
}
// Retrieve all XDG base directories for configuration files.
func getXDGConfigDirs() (result []string) {
home := getXDGHomeDir("XDG_CONFIG_HOME", ".config")
if home != "" {
result = append(result, home)
}
dirs := os.Getenv("XDG_CONFIG_DIRS")
if dirs == "" {
dirs = "/etc/xdg"
}
for _, path := range strings.Split(dirs, ":") {
if path != "" {
result = append(result, path)
}
}
return
}
func resolveRelativeConfigFilename(filename string) string {
return resolveRelativeFilenameGeneric(getXDGConfigDirs(),
filepath.Join(projectName, filename))
}
func findTildeHome(username string) string {
if username != "" {
if u, _ := user.Lookup(username); u != nil {
return u.HomeDir
}
} else if u, _ := user.Current(); u != nil {
return u.HomeDir
} else if v, ok := os.LookupEnv("HOME"); ok {
return v
}
printDebug("failed to expand the home directory for %s", username)
return "~" + username
}
func resolveFilename(filename string, relativeCB func(string) string) string {
// Absolute path is absolute.
if filename == "" || filename[0] == filepath.Separator {
return filename
}
if filename[0] != '~' {
return relativeCB(filename)
}
// Paths to home directories ought to be absolute.
var n int
for n = 0; n < len(filename); n++ {
if filename[n] == filepath.Separator {
break
}
}
return findTildeHome(filename[1:n]) + filename[n:]
}
// --- Simple file I/O ---------------------------------------------------------
// Overwrites filename contents with data; creates directories as needed.
func writeFile(path string, data []byte) error {
if dir := filepath.Dir(path); dir != "." {
if err := os.MkdirAll(dir, 0755); err != nil {
return err
}
}
return ioutil.WriteFile(path, data, 0644)
}
// Wrapper for writeFile that makes sure that the new data has been written
// to disk in its entirety before overriding the old file.
func writeFileSafe(path string, data []byte) error {
temp := path + ".new"
if err := writeFile(temp, data); err != nil {
return err
}
return os.Rename(temp, path)
}
// --- Simple configuration ----------------------------------------------------
// This is the bare minimum to make an application configurable.
// Keys are stripped of surrounding whitespace, values are not.
type simpleConfigItem struct {
key string // INI key
def string // default value
description string // documentation
}
type simpleConfig map[string]string
func (sc simpleConfig) loadDefaults(table []simpleConfigItem) {
for _, item := range table {
sc[item.key] = item.def
}
}
func (sc simpleConfig) updateFromFile() error {
basename := projectName + ".conf"
path := resolveFilename(basename, resolveRelativeConfigFilename)
if path == "" {
return &os.PathError{
Op: "cannot find",
Path: basename,
Err: os.ErrNotExist,
}
}
f, err := os.Open(path)
if err != nil {
return err
}
defer f.Close()
scanner := bufio.NewScanner(f)
for lineNo := 1; scanner.Scan(); lineNo++ {
line := strings.TrimLeft(scanner.Text(), " \t")
if line == "" || strings.HasPrefix(line, "#") {
continue
}
equals := strings.IndexByte(line, '=')
if equals <= 0 {
return fmt.Errorf("%s:%d: malformed line", path, lineNo)
}
sc[strings.TrimRight(line[:equals], " \t")] = line[equals+1:]
}
return scanner.Err()
}
func writeConfigurationFile(pathHint string, data []byte) (string, error) {
path := pathHint
if path == "" {
path = filepath.Join(getXDGHomeDir("XDG_CONFIG_HOME", ".config"),
projectName, projectName+".conf")
}
if err := writeFileSafe(path, data); err != nil {
return "", err
}
return path, nil
}
func simpleConfigWriteDefault(pathHint string, prolog string,
table []simpleConfigItem) (string, error) {
data := []byte(prolog)
for _, item := range table {
data = append(data, fmt.Sprintf("# %s\n%s=%s\n",
item.description, item.key, item.def)...)
}
return writeConfigurationFile(pathHint, data)
}
// Convenience wrapper suitable for most simple applications.
func callSimpleConfigWriteDefault(pathHint string, table []simpleConfigItem) {
prologLines := []string{
`# ` + projectName + ` ` + projectVersion + ` configuration file`,
"#",
`# Relative paths are searched for in ${XDG_CONFIG_HOME:-~/.config}`,
`# /` + projectName + ` as well as in $XDG_CONFIG_DIRS/` + projectName,
``,
``,
}
path, err := simpleConfigWriteDefault(
pathHint, strings.Join(prologLines, "\n"), table)
if err != nil {
exitFatal("%s", err)
}
printStatus("configuration written to `%s'", path)
}
// --- Configuration -----------------------------------------------------------
var configTable = []simpleConfigItem{
{"server_name", "", "Server name"},
{"server_info", "My server", "Brief server description"},
{"motd", "", "MOTD filename"},
{"catalog", "", "Localisation catalog"},
{"bind", ":6667", "Bind addresses of the IRC server"},
{"tls_cert", "", "Server TLS certificate (PEM)"},
{"tls_key", "", "Server TLS private key (PEM)"},
{"webirc_password", "", "Password for WebIRC"},
{"operators", "", "IRCop TLS certificate SHA-256 fingerprints"},
{"max_connections", "0", "Global connection limit"},
{"ping_interval", "180", "Interval between PINGs (sec)"},
}
// --- Rate limiter ------------------------------------------------------------
type floodDetector struct {
interval time.Duration // interval for the limit in seconds
limit uint // maximum number of events allowed
timestamps []time.Time // timestamps of last events
pos uint // index of the oldest event
}
func newFloodDetector(interval time.Duration, limit uint) *floodDetector {
return &floodDetector{
interval: interval,
limit: limit,
timestamps: make([]time.Time, limit+1),
pos: 0,
}
}
func (fd *floodDetector) check() bool {
now := time.Now()
fd.timestamps[fd.pos] = now
fd.pos++
if fd.pos > fd.limit {
fd.pos = 0
}
var count uint
begin := now.Add(-fd.interval)
for _, ts := range fd.timestamps {
if ts.After(begin) {
count++
}
}
return count <= fd.limit
}
// --- IRC token validation ----------------------------------------------------
// Everything as per RFC 2812
const (
ircMaxNickname = 9
ircMaxHostname = 63
ircMaxChannelName = 50
ircMaxMessageLength = 510
)
const (
reClassSpecial = "\\[\\]\\\\`_^{|}"
// "shortname" from RFC 2812 doesn't work how its author thought it would.
reShortname = "[0-9A-Za-z](-*[0-9A-Za-z])*"
)
var (
reHostname = regexp.MustCompile(
`^` + reShortname + `(\.` + reShortname + `)*$`)
// Extending ASCII to the whole range of Unicode letters.
reNickname = regexp.MustCompile(
`^[\pL` + reClassSpecial + `][\pL` + reClassSpecial + `0-9-]*$`)
// Notably, this won't match invalid UTF-8 characters, although the
// behaviour seems to be unstated in the documentation.
reUsername = regexp.MustCompile(`^[^\0\r\n @]+$`)
reChannelName = regexp.MustCompile(`^[^\0\007\r\n ,:]+$`)
reKey = regexp.MustCompile(`^[^\r\n\f\t\v ]{1,23}$`)
reUserMask = regexp.MustCompile(`^[^!@]+![^!@]+@[^@!]+$`)
reFingerprint = regexp.MustCompile(`^[a-fA-F0-9]{64}$`)
)
func ircValidateHostname(hostname string) error {
if hostname == "" {
return errors.New("the value is empty")
}
if !reHostname.MatchString(hostname) {
return errors.New("invalid format")
}
if len(hostname) > ircMaxHostname {
return errors.New("the value is too long")
}
return nil
}
func ircIsValidNickname(nickname string) bool {
return len(nickname) <= ircMaxNickname && reNickname.MatchString(nickname)
}
func ircIsValidUsername(username string) bool {
// XXX: We really should put a limit on this
// despite the RFC not mentioning one.
return reUsername.MatchString(username)
}
func ircIsValidChannelName(name string) bool {
return len(name) <= ircMaxChannelName && reChannelName.MatchString(name)
}
func ircIsValidKey(key string) bool {
// XXX: Should be 7-bit as well but whatever.
return reKey.MatchString(key)
}
func ircIsValidUserMask(mask string) bool {
return reUserMask.MatchString(mask)
}
func ircIsValidFingerprint(fp string) bool {
return reFingerprint.MatchString(fp)
}
// --- Clients (equals users) --------------------------------------------------
type connCloseWriter interface {
net.Conn
CloseWrite() error
}
const ircSupportedUserModes = "aiwros"
const (
ircUserModeInvisible uint = 1 << iota
ircUserModeRxWallops
ircUserModeRestricted
ircUserModeOperator
ircUserModeRxServerNotices
)
const (
ircCapMultiPrefix uint = 1 << iota
ircCapInviteNotify
ircCapEchoMessage
ircCapUserhostInNames
ircCapServerTime
)
type client struct {
transport net.Conn // underlying connection
tls *tls.Conn // TLS, if detected
conn connCloseWriter // high-level connection
recvQ []byte // unprocessed input
sendQ []byte // unprocessed output
reading bool // whether a reading goroutine is running
writing bool // whether a writing goroutine is running
closing bool // whether we're closing the connection
killTimer *time.Timer // hard kill timeout
opened time.Time // when the connection was opened
nSentMessages uint // number of sent messages total
sentBytes int // number of sent bytes total
nReceivedMessages uint // number of received messages total
receivedBytes int // number of received bytes total
hostname string // hostname or IP shown to the network
port string // port of the peer as a string
address string // full network address
pingTimer *time.Timer // we should send a PING
timeoutTimer *time.Timer // connection seems to be dead
registered bool // the user has registered
capNegotiating bool // negotiating capabilities
capsEnabled uint // enabled capabilities
capVersion uint // CAP protocol version
tlsCertFingerprint string // client certificate fingerprint
nickname string // IRC nickname (main identifier)
username string // IRC username
realname string // IRC realname (or e-mail)
mode uint // user's mode
awayMessage string // away message
lastActive time.Time // last PRIVMSG, to get idle time
invites map[string]bool // channel invitations by operators
antiflood *floodDetector // flood detector
}
// --- Channels ----------------------------------------------------------------
const ircSupportedChanModes = "ov" + "beI" + "imnqpst" + "kl"
const (
ircChanModeInviteOnly uint = 1 << iota
ircChanModeModerated
ircChanModeNoOutsideMsgs
ircChanModeQuiet
ircChanModePrivate
ircChanModeSecret
ircChanModeProtectedTopic
ircChanModeOperator
ircChanModeVoice
)
type channel struct {
name string // channel name
modes uint // channel modes
key string // channel key
userLimit int // user limit or -1
created time.Time // creation time
topic string // channel topic
topicWho string // who set the topic
topicTime time.Time // when the topic was set
userModes map[*client]uint // modes for all channel users
banList []string // ban list
exceptionList []string // exceptions from bans
inviteList []string // exceptions from +I
}
func (ch *channel) getMode(discloseSecrets bool) string {
var buf []byte
if 0 != ch.modes&ircChanModeInviteOnly {
buf = append(buf, 'i')
}
if 0 != ch.modes&ircChanModeModerated {
buf = append(buf, 'm')
}
if 0 != ch.modes&ircChanModeNoOutsideMsgs {
buf = append(buf, 'n')
}
if 0 != ch.modes&ircChanModeQuiet {
buf = append(buf, 'q')
}
if 0 != ch.modes&ircChanModePrivate {
buf = append(buf, 'p')
}
if 0 != ch.modes&ircChanModeSecret {
buf = append(buf, 's')
}
if 0 != ch.modes&ircChanModeProtectedTopic {
buf = append(buf, 'r')
}
if ch.userLimit != -1 {
buf = append(buf, 'l')
}
if ch.key != "" {
buf = append(buf, 'k')
}
// XXX: Is it correct to split it? Try it on an existing implementation.
if discloseSecrets {
if ch.userLimit != -1 {
buf = append(buf, fmt.Sprintf(" %d", ch.userLimit)...)
}
if ch.key != "" {
buf = append(buf, fmt.Sprintf(" %s", ch.key)...)
}
}
return string(buf)
}
// --- IRC server context ------------------------------------------------------
type whowasInfo struct {
nickname, username, realname, hostname string
}
func newWhowasInfo(c *client) *whowasInfo {
return &whowasInfo{
nickname: c.nickname,
username: c.username,
realname: c.realname,
hostname: c.hostname,
}
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
type ircCommand struct {
requiresRegistration bool
handler func(*message, *client)
nReceived uint // number of commands received
bytesReceived int // number of bytes received total
}
type preparedEvent struct {
client *client
host string // client's hostname or literal IP address
isTLS bool // the client seems to use TLS
}
type readEvent struct {
client *client
data []byte // new data from the client
err error // read error
}
type writeEvent struct {
client *client
written int // amount of bytes written
err error // write error
}
// TODO: Maybe we want to keep it in a struct?
// A better question might be: can we run multiple instances of it?
var (
// network
listeners []net.Listener
clients = make(map[*client]bool)
// IRC state
// XXX: Beware that maps with identifier keys need to be indexed correctly.
// We might want to enforce accessor functions for users and channels.
started time.Time // when the server has been started
users = make(map[string]*client) // maps nicknames to clients
channels = make(map[string]*channel) // maps channel names to data
whowas = make(map[string]*whowasInfo) // WHOWAS registry
// event loop
quitting bool
quitTimer <-chan time.Time
sigs = make(chan os.Signal, 1)
conns = make(chan net.Conn)
prepared = make(chan preparedEvent)
reads = make(chan readEvent)
writes = make(chan writeEvent)
timers = make(chan func())
// configuration
config simpleConfig // server configuration
tlsConf *tls.Config // TLS connection configuration
serverName string // our server name
pingInterval time.Duration // ping interval
maxConnections int // max connections allowed or 0
motd []string // MOTD (none if empty)
catalog map[int]string // message catalog for server msgs
operators map[string]bool // TLS certificate fingerprints for IRCops
)
// Forcefully tear down all connections.
func forceQuit(reason string) {
if !quitting {
exitFatal("forceQuit called without initiateQuit")
}
printStatus("forced shutdown (%s)", reason)
for c := range clients {
// initiateQuit has already unregistered the client.
c.kill("Shutting down")
}
}
// Initiate a clean shutdown of the whole daemon.
func initiateQuit() {
printStatus("shutting down")
for _, ln := range listeners {
if err := ln.Close(); err != nil {
printError("%s", err)
}
}
for c := range clients {
c.closeLink("Shutting down")
}
quitTimer = time.After(5 * time.Second)
quitting = true
}
func ircChannelCreate(name string) *channel {
ch := &channel{
name: name,
userLimit: -1,
created: time.Now(),
userModes: make(map[*client]uint),
}
channels[ircToCanon(name)] = ch
return ch
}
func ircChannelDestroyIfEmpty(ch *channel) {
if len(ch.userModes) == 0 {
delete(channels, ircToCanon(ch.name))
}
}
func ircNotifyRoommates(c *client, message string) {
targets := make(map[*client]bool)
for _, ch := range channels {
_, present := ch.userModes[c]
if !present || 0 != ch.modes&ircChanModeQuiet {
continue
}
for client := range ch.userModes {
targets[client] = true
}
}
for roommate := range targets {
if roommate != c {
roommate.send(message)
}
}
}
// --- Clients (continued) -----------------------------------------------------
func (c *client) printDebug(format string, args ...interface{}) {
if debugMode {
printDebug("(%s) %s", c.address, fmt.Sprintf(format, args...))
}
}
func ircAppendClientModes(m uint, mode []byte) []byte {
if 0 != m&ircUserModeInvisible {
mode = append(mode, 'i')
}
if 0 != m&ircUserModeRxWallops {
mode = append(mode, 'w')
}
if 0 != m&ircUserModeRestricted {
mode = append(mode, 'r')
}
if 0 != m&ircUserModeOperator {
mode = append(mode, 'o')
}
if 0 != m&ircUserModeRxServerNotices {
mode = append(mode, 's')
}
return mode
}
func (c *client) getMode() string {
var mode []byte
if c.awayMessage != "" {
mode = append(mode, 'a')
}
return string(ircAppendClientModes(c.mode, mode))
}
func (c *client) send(line string) {
if c.conn == nil || c.closing {
return
}
oldSendQLen := len(c.sendQ)
// So far there's only one message tag we use, so we can do it simple;
// note that a 1024-character limit applies to messages with tags on.
if 0 != c.capsEnabled&ircCapServerTime {
c.sendQ = time.Now().UTC().
AppendFormat(c.sendQ, "@time=2006-01-02T15:04:05.000Z ")
}
bytes := []byte(line)
if len(bytes) > ircMaxMessageLength {
bytes = bytes[:ircMaxMessageLength]
}
c.printDebug("<- %s", bytes)
// TODO: Kill the connection above some "SendQ" threshold (careful!)
c.sendQ = append(c.sendQ, bytes...)
c.sendQ = append(c.sendQ, "\r\n"...)
c.flushSendQ()
// Technically we haven't sent it yet but that's a minor detail
c.nSentMessages++
c.sentBytes += len(c.sendQ) - oldSendQLen
}
func (c *client) sendf(format string, a ...interface{}) {
c.send(fmt.Sprintf(format, a...))
}
func (c *client) addToWhowas() {
// Only keeping one entry for each nickname.
// TODO: Make sure this list doesn't get too long, for example by
// putting them in a linked list ordered by time.
whowas[ircToCanon(c.nickname)] = newWhowasInfo(c)
}
func (c *client) nicknameOrStar() string {
if c.nickname == "" {
return "*"
}
return c.nickname
}
func (c *client) unregister(reason string) {
if !c.registered {
return
}
ircNotifyRoommates(c, fmt.Sprintf(":%s!%s@%s QUIT :%s",
c.nickname, c.username, c.hostname, reason))
// The QUIT message will take care of state on clients.
for _, ch := range channels {
delete(ch.userModes, c)
ircChannelDestroyIfEmpty(ch)
}
c.addToWhowas()
delete(users, ircToCanon(c.nickname))
c.nickname = ""
c.registered = false
}
// Close the connection and forget about the client.
func (c *client) kill(reason string) {
if reason == "" {
c.unregister("Client exited")
} else {
c.unregister(reason)
}
c.printDebug("client destroyed (%s)", reason)
// Try to send a "close notify" alert if the TLS object is ready,
// otherwise just tear down the transport.
if c.conn != nil {
_ = c.conn.Close()
} else {
_ = c.transport.Close()
}
c.cancelTimers()
delete(clients, c)
}
// Tear down the client connection, trying to do so in a graceful manner.
func (c *client) closeLink(reason string) {
// Let's just cut the connection, the client can try again later.
// We also want to avoid accidentally writing to the socket before
// address resolution has finished.
if c.conn == nil {
c.kill(reason)
return
}
if c.closing {
return
}
// We push an "ERROR" message to the write buffer and let the writer send
// it, with some arbitrary timeout. The "closing" state makes sure
// that a/ we ignore any successive messages, and b/ that the connection
// is killed after the write buffer is transferred and emptied.
// (Since we send this message, we don't need to call CloseWrite here.)
c.sendf("ERROR :Closing link: %s[%s] (%s)",
c.nicknameOrStar(), c.hostname /* TODO host IP? */, reason)
c.closing = true
c.unregister(reason)
c.setKillTimer()
}
func (c *client) inMaskList(masks []string) bool {
client := fmt.Sprintf("%s!%s@%s", c.nickname, c.username, c.hostname)
for _, mask := range masks {
if ircFnmatch(mask, client) {
return true
}
}
return false
}
func (c *client) getTLSCertFingerprint() string {
if c.tls == nil {
return ""
}
peerCerts := c.tls.ConnectionState().PeerCertificates
if len(peerCerts) == 0 {
return ""
}
hash := sha256.Sum256(peerCerts[0].Raw)
return hex.EncodeToString(hash[:])
}
// --- Timers ------------------------------------------------------------------
// Free the resources of timers that haven't fired yet and for timers that are
// in between firing and being collected by the event loop, mark that the event
// should not be acted upon.
func (c *client) cancelTimers() {
for _, timer := range []**time.Timer{
&c.killTimer, &c.timeoutTimer, &c.pingTimer,
} {
if *timer != nil {
(*timer).Stop()
*timer = nil
}
}
}
// Arrange for a function to be called later from the main goroutine.
func (c *client) setTimer(timer **time.Timer, delay time.Duration, cb func()) {
c.cancelTimers()
var identityCapture *time.Timer
identityCapture = time.AfterFunc(delay, func() {
timers <- func() {
// The timer might have been cancelled or even replaced.
// When the client is killed, this will be nil.
if *timer == identityCapture {
cb()
}
}
})
*timer = identityCapture
}
func (c *client) setKillTimer() {
c.setTimer(&c.killTimer, pingInterval, func() {
c.kill("Timeout")
})
}
func (c *client) setTimeoutTimer() {
c.setTimer(&c.timeoutTimer, pingInterval, func() {
c.closeLink(fmt.Sprintf("Ping timeout: >%d seconds",
pingInterval/time.Second))
})
}
func (c *client) setPingTimer() {
c.setTimer(&c.pingTimer, pingInterval, func() {
c.sendf("PING :%s", serverName)
c.setTimeoutTimer()
})
}
// --- IRC command handling ----------------------------------------------------
func (c *client) makeReply(id int, ap ...interface{}) string {
s := fmt.Sprintf(":%s %03d %s ", serverName, id, c.nicknameOrStar())
if reply, ok := catalog[id]; ok {
return s + fmt.Sprintf(reply, ap...)
}
return s + fmt.Sprintf(defaultReplies[id], ap...)
}
// XXX: This way simple static analysis cannot typecheck the arguments, so we
// need to be careful.
func (c *client) sendReply(id int, args ...interface{}) {
c.send(c.makeReply(id, args...))
}
// Send a space-separated list of words across as many replies as needed.
func (c *client) sendReplyVector(id int, items []string, args ...interface{}) {
common := c.makeReply(id, args...)
// We always send at least one message (there might be a client that
// expects us to send this message at least once).
if len(items) == 0 {
items = append(items, "")
}
for len(items) > 0 {
// If not even a single item fits in the limit (which may happen,
// in theory) it just gets cropped. We could also skip it.
reply := append([]byte(common), items[0]...)
items = items[1:]
// Append as many items as fits in a single message.
for len(items) > 0 &&
len(reply)+1+len(items[0]) <= ircMaxMessageLength {
reply = append(reply, ' ')
reply = append(reply, items[0]...)
items = items[1:]
}
c.send(string(reply))
}
}
func (c *client) sendMOTD() {
if len(motd) == 0 {
c.sendReply(ERR_NOMOTD)
return
}
c.sendReply(RPL_MOTDSTART, serverName)
for _, line := range motd {
c.sendReply(RPL_MOTD, line)
}
c.sendReply(RPL_ENDOFMOTD)
}
func (c *client) sendLUSERS() {
nUsers, nServices, nOpers, nUnknown := 0, 0, 0, 0
for c := range clients {
if c.registered {
nUsers++
} else {
nUnknown++
}
if 0 != c.mode&ircUserModeOperator {
nOpers++
}
}
nChannels := 0
for _, ch := range channels {
if 0 != ch.modes&ircChanModeSecret {
nChannels++
}
}
c.sendReply(RPL_LUSERCLIENT, nUsers, nServices, 1 /* servers total */)
if nOpers != 0 {
c.sendReply(RPL_LUSEROP, nOpers)
}
if nUnknown != 0 {
c.sendReply(RPL_LUSERUNKNOWN, nUnknown)
}
if nChannels != 0 {
c.sendReply(RPL_LUSERCHANNELS, nChannels)
}
c.sendReply(RPL_LUSERME, nUsers+nServices+nUnknown, 0 /* peer servers */)
}
func ircIsThisMe(target string) bool {
// Target servers can also be matched by their users
if ircFnmatch(target, serverName) {
return true
}
_, ok := users[ircToCanon(target)]
return ok
}
func (c *client) sendISUPPORT() {
// Only # channels, +e supported, +I supported, unlimited arguments to MODE.
c.sendReply(RPL_ISUPPORT, fmt.Sprintf("CHANTYPES=# EXCEPTS INVEX MODES"+
" TARGMAX=WHOIS:,LIST:,NAMES:,PRIVMSG:1,NOTICE:1,KICK:"+
" NICKLEN=%d CHANNELLEN=%d", ircMaxNickname, ircMaxChannelName))
}
func (c *client) tryFinishRegistration() {
if c.registered || c.capNegotiating {
return
}
if c.nickname == "" || c.username == "" {
return
}
c.registered = true
c.sendReply(RPL_WELCOME, c.nickname, c.username, c.hostname)
c.sendReply(RPL_YOURHOST, serverName, projectVersion)
// The purpose of this message eludes me.
c.sendReply(RPL_CREATED, started.Format("Mon, 02 Jan 2006"))
c.sendReply(RPL_MYINFO, serverName, projectVersion,
ircSupportedUserModes, ircSupportedChanModes)
c.sendISUPPORT()
c.sendLUSERS()
c.sendMOTD()
if mode := c.getMode(); mode != "" {
c.sendf(":%s MODE %s :+%s", c.nickname, c.nickname, mode)
}
c.tlsCertFingerprint = c.getTLSCertFingerprint()
if c.tlsCertFingerprint != "" {
c.sendf(":%s NOTICE %s :Your TLS client certificate fingerprint is %s",
serverName, c.nickname, c.tlsCertFingerprint)
}
delete(whowas, ircToCanon(c.nickname))
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// IRCv3 capability negotiation. See http://ircv3.org for details.
type ircCapArgs struct {
subcommand string // the subcommand being processed
fullParams string // whole parameter string
params []string // split parameters
target string // target parameter for replies
}
var ircCapTable = []struct {
flag uint // flag
name string // name of the capability
}{
{ircCapMultiPrefix, "multi-prefix"},
{ircCapInviteNotify, "invite-notify"},
{ircCapEchoMessage, "echo-message"},
{ircCapUserhostInNames, "userhost-in-names"},
{ircCapServerTime, "server-time"},
}
func (c *client) handleCAPLS(a *ircCapArgs) {
if len(a.params) == 1 {
if ver, err := strconv.ParseUint(a.params[0], 10, 32); err != nil {
c.sendReply(ERR_INVALIDCAPCMD, a.subcommand,
"Ignoring invalid protocol version number")
} else {
c.capVersion = uint(ver)
}
}
c.capNegotiating = true
c.sendf(":%s CAP %s LS :multi-prefix invite-notify echo-message"+
" userhost-in-names server-time", serverName, a.target)
}
func (c *client) handleCAPLIST(a *ircCapArgs) {
caps := []string{}
for _, cap := range ircCapTable {
if 0 != c.capsEnabled&cap.flag {
caps = append(caps, cap.name)
}
}
c.sendf(":%s CAP %s LIST :%s", serverName, a.target,
strings.Join(caps, " "))
}
func ircDecodeCapability(name string) uint {
for _, cap := range ircCapTable {
if cap.name == name {
return cap.flag
}
}
return 0
}
func (c *client) handleCAPREQ(a *ircCapArgs) {
c.capNegotiating = true
newCaps := c.capsEnabled
ok := true
for _, param := range a.params {
removing := false
name := param
if name[:1] == "-" {
removing = true
name = name[1:]
}
if cap := ircDecodeCapability(name); cap == 0 {
ok = false
} else if removing {
newCaps &= ^cap
} else {
newCaps |= cap
}
}
if ok {
c.capsEnabled = newCaps
c.sendf(":%s CAP %s ACK :%s", serverName, a.target, a.fullParams)
} else {
c.sendf(":%s CAP %s NAK :%s", serverName, a.target, a.fullParams)
}
}
func (c *client) handleCAPACK(a *ircCapArgs) {
if len(a.params) > 0 {
c.sendReply(ERR_INVALIDCAPCMD, a.subcommand,
"No acknowledgable capabilities supported")
}
}
func (c *client) handleCAPEND(a *ircCapArgs) {
c.capNegotiating = false
c.tryFinishRegistration()
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
var ircCapHandlers = map[string]func(*client, *ircCapArgs){
"LS": (*client).handleCAPLS,
"LIST": (*client).handleCAPLIST,
"REQ": (*client).handleCAPREQ,
"ACK": (*client).handleCAPACK,
"END": (*client).handleCAPEND,
}
// XXX: Maybe these also deserve to be methods for client? They operate on
// global state, though.
func ircParseWEBIRCOptions(options string, out map[string]string) {
for _, option := range strings.Split(options, " ") {
if equal := strings.IndexByte(option, '='); equal < 0 {
out[option] = ""
} else {
out[option[:equal]] = ircUnescapeMessageTag(option[equal+1:])
}
}
}
func ircHandleWEBIRC(msg *message, c *client) {
if len(msg.params) < 4 {
c.sendReply(ERR_NEEDMOREPARAMS, msg.command)
return
}
password, gateway, hostname := msg.params[0], msg.params[1], msg.params[2]
if config["webirc_password"] != password {
c.closeLink("Invalid WebIRC password")
return
}
options := make(map[string]string)
if len(msg.params) >= 5 {
ircParseWEBIRCOptions(msg.params[4], options)
}
c.hostname = hostname
c.port = "WebIRC-" + gateway
c.address = net.JoinHostPort(hostname, c.port)
// Note that this overrides the gateway's certificate, conditionally.
fp, _ := options["certfp-sha-256"]
if _, secure := options["secure"]; secure && ircIsValidFingerprint(fp) {
c.tlsCertFingerprint = strings.ToLower(fp)
}
}
func ircHandleCAP(msg *message, c *client) {
if len(msg.params) < 1 {
c.sendReply(ERR_NEEDMOREPARAMS, msg.command)
return
}
args := &ircCapArgs{
target: c.nicknameOrStar(),
subcommand: msg.params[0],
fullParams: "",
params: []string{},
}
if len(msg.params) > 1 {
args.fullParams = msg.params[1]
args.params = splitString(args.fullParams, " ", true)
}
if fn, ok := ircCapHandlers[ircToCanon(args.subcommand)]; !ok {
c.sendReply(ERR_INVALIDCAPCMD, args.subcommand,
"Invalid CAP subcommand")
} else {
fn(c, args)
}
}
func ircHandlePASS(msg *message, c *client) {
if c.registered {
c.sendReply(ERR_ALREADYREGISTERED)
} else if len(msg.params) < 1 {
c.sendReply(ERR_NEEDMOREPARAMS, msg.command)
}
// We have TLS client certificates for this purpose; ignoring.
}
func ircHandleNICK(msg *message, c *client) {
if len(msg.params) < 1 {
c.sendReply(ERR_NONICKNAMEGIVEN)
return
}
nickname := msg.params[0]
if !ircIsValidNickname(nickname) {
c.sendReply(ERR_ERRONEOUSNICKNAME, nickname)
return
}
nicknameCanon := ircToCanon(nickname)
if client, ok := users[nicknameCanon]; ok && client != c {
c.sendReply(ERR_NICKNAMEINUSE, nickname)
return
}
if c.registered {
c.addToWhowas()
message := fmt.Sprintf(":%s!%s@%s NICK :%s",
c.nickname, c.username, c.hostname, nickname)
ircNotifyRoommates(c, message)
c.send(message)
}
// Release the old nickname and allocate a new one.
if c.nickname != "" {
delete(users, ircToCanon(c.nickname))
}
c.nickname = nickname
users[nicknameCanon] = c
c.tryFinishRegistration()
}
func ircHandleUSER(msg *message, c *client) {
if c.registered {
c.sendReply(ERR_ALREADYREGISTERED)
return
}
if len(msg.params) < 4 {
c.sendReply(ERR_NEEDMOREPARAMS, msg.command)
return
}
username, mode, realname := msg.params[0], msg.params[1], msg.params[3]
// Unfortunately, the protocol doesn't give us any means of rejecting it.
if !ircIsValidUsername(username) {
username = "*"
}
c.username = username
c.realname = realname
c.mode = 0
if m, err := strconv.ParseUint(mode, 10, 32); err != nil {
if 0 != m&4 {
c.mode |= ircUserModeRxWallops
}
if 0 != m&8 {
c.mode |= ircUserModeInvisible
}
}
c.tryFinishRegistration()
}
func ircHandleUSERHOST(msg *message, c *client) {
if len(msg.params) < 1 {
c.sendReply(ERR_NEEDMOREPARAMS, msg.command)
return
}
var reply []byte
for i := 0; i < 5 && i < len(msg.params); i++ {
nick := msg.params[i]
target := users[ircToCanon(nick)]
if target == nil {
continue
}
if i != 0 {
reply = append(reply, ' ')
}
reply = append(reply, nick...)
if 0 != target.mode&ircUserModeOperator {
reply = append(reply, '*')
}
if target.awayMessage != "" {
reply = append(reply, "=-"...)
} else {
reply = append(reply, "=+"...)
}
reply = append(reply, (target.username + "@" + target.hostname)...)
}
c.sendReply(RPL_USERHOST, string(reply))
}
func ircHandleLUSERS(msg *message, c *client) {
if len(msg.params) > 1 && !ircIsThisMe(msg.params[1]) {
c.sendReply(ERR_NOSUCHSERVER, msg.params[1])
return
}
c.sendLUSERS()
}
func ircHandleMOTD(msg *message, c *client) {
if len(msg.params) > 0 && !ircIsThisMe(msg.params[0]) {
c.sendReply(ERR_NOSUCHSERVER, msg.params[1])
return
}
c.sendMOTD()
}
func ircHandlePING(msg *message, c *client) {
// XXX: The RFC is pretty incomprehensible about the exact usage.
if len(msg.params) > 1 && !ircIsThisMe(msg.params[1]) {
c.sendReply(ERR_NOSUCHSERVER, msg.params[1])
} else if len(msg.params) < 1 {
c.sendReply(ERR_NOORIGIN)
} else {
c.sendf(":%s PONG :%s", serverName, msg.params[0])
}
}
func ircHandlePONG(msg *message, c *client) {
// We are the only server, so we don't have to care too much.
if len(msg.params) < 1 {
c.sendReply(ERR_NOORIGIN)
return
}
// Set a new timer to send another PING
c.setPingTimer()
}
func ircHandleQUIT(msg *message, c *client) {
reason := c.nickname
if len(msg.params) > 0 {
reason = msg.params[0]
}
c.closeLink("Quit: " + reason)
}
func ircHandleTIME(msg *message, c *client) {
if len(msg.params) > 0 && !ircIsThisMe(msg.params[0]) {
c.sendReply(ERR_NOSUCHSERVER, msg.params[0])
return
}
c.sendReply(RPL_TIME, serverName,
time.Now().Format("Mon Jan _2 2006 15:04:05"))
}
func ircHandleVERSION(msg *message, c *client) {
if len(msg.params) > 0 && !ircIsThisMe(msg.params[0]) {
c.sendReply(ERR_NOSUCHSERVER, msg.params[0])
return
}
postVersion := 0
if debugMode {
postVersion = 1
}
c.sendReply(RPL_VERSION, projectVersion, postVersion, serverName,
projectName+" "+projectVersion)
c.sendISUPPORT()
}
func ircChannelMulticast(ch *channel, msg string, except *client) {
for c := range ch.userModes {
if c != except {
c.send(msg)
}
}
}
func ircModifyMode(mask *uint, mode uint, add bool) bool {
orig := *mask
if add {
*mask |= mode
} else {
*mask &= ^mode
}
return *mask != orig
}
func ircUpdateUserMode(c *client, newMode uint) {
oldMode := c.mode
c.mode = newMode
added, removed := newMode & ^oldMode, oldMode & ^newMode
var diff []byte
if added != 0 {
diff = append(diff, '+')
diff = ircAppendClientModes(added, diff)
}
if removed != 0 {
diff = append(diff, '-')
diff = ircAppendClientModes(removed, diff)
}
if len(diff) > 0 {
c.sendf(":%s MODE %s :%s", c.nickname, c.nickname, string(diff))
}
}
func ircHandleUserModeChange(c *client, modeString string) {
newMode := c.mode
adding := true
for _, flag := range modeString {
switch flag {
case '+':
adding = true
case '-':
adding = false
case 'a':
// Ignore, the client should use AWAY.
case 'i':
ircModifyMode(&newMode, ircUserModeInvisible, adding)
case 'w':
ircModifyMode(&newMode, ircUserModeRxWallops, adding)
case 'r':
// It's not possible ot un-restrict yourself.
if adding {
newMode |= ircUserModeRestricted
}
case 'o':
if !adding {
newMode &= ^ircUserModeOperator
} else if operators[c.tlsCertFingerprint] {
newMode |= ircUserModeOperator
} else {
c.sendf(":%s NOTICE %s :Either you're not using an TLS"+
" client certificate, or the fingerprint doesn't match",
serverName, c.nickname)
}
case 's':
ircModifyMode(&newMode, ircUserModeRxServerNotices, adding)
default:
c.sendReply(ERR_UMODEUNKNOWNFLAG)
return
}
}
ircUpdateUserMode(c, newMode)
}
func ircSendChannelList(c *client, channelName string, list []string,
reply, endReply int) {
for _, line := range list {
c.sendReply(reply, channelName, line)
}
c.sendReply(endReply, channelName)
}
func ircCheckExpandUserMask(mask string) string {
var result []byte
result = append(result, mask...)
// Make sure it is a complete mask.
if bytes.IndexByte(result, '!') < 0 {
result = append(result, "!*"...)
}
if bytes.IndexByte(result, '@') < 0 {
result = append(result, "@*"...)
}
// And validate whatever the result is.
s := string(result)
if !ircIsValidUserMask(s) {
return ""
}
return s
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// Channel MODE command handling. This is by far the worst command to implement
// from the whole RFC; don't blame me if it doesn't work exactly as expected.
type modeProcessor struct {
params []string // mode string parameters
c *client // who does the changes
ch *channel // the channel we're modifying
present bool // c present on ch
modes uint // channel user modes
adding bool // currently adding modes
modeChar byte // currently processed mode char
added []byte // added modes
removed []byte // removed modes
output *[]byte // "added" or "removed"
addedParams []string // params for added modes
removedParams []string // params for removed modes
outputParams *[]string // "addedParams" or "removedParams"
}
func (mp *modeProcessor) nextParam() string {
if len(mp.params) == 0 {
return ""
}
param := mp.params[0]
mp.params = mp.params[1:]
return param
}
func (mp *modeProcessor) checkOperator() bool {
if (mp.present && 0 != mp.modes&ircChanModeOperator) ||
0 != mp.c.mode&ircUserModeOperator {
return true
}
mp.c.sendReply(ERR_CHANOPRIVSNEEDED, mp.ch.name)
return false
}
func (mp *modeProcessor) doUser(mode uint) {
target := mp.nextParam()
if !mp.checkOperator() || target == "" {
return
}
if client := users[ircToCanon(target)]; client == nil {
mp.c.sendReply(ERR_NOSUCHNICK, target)
} else if modes, present := mp.ch.userModes[client]; !present {
mp.c.sendReply(ERR_USERNOTINCHANNEL, target, mp.ch.name)
} else if ircModifyMode(&modes, mode, mp.adding) {
mp.ch.userModes[client] = modes
*mp.output = append(*mp.output, mp.modeChar)
*mp.outputParams = append(*mp.outputParams, client.nickname)
}
}
func (mp *modeProcessor) doChan(mode uint) bool {
if !mp.checkOperator() || !ircModifyMode(&mp.ch.modes, mode, mp.adding) {
return false
}
*mp.output = append(*mp.output, mp.modeChar)
return true
}
func (mp *modeProcessor) doChanRemove(modeChar byte, mode uint) {
if mp.adding && ircModifyMode(&mp.ch.modes, mode, false) {
mp.removed = append(mp.removed, modeChar)
}
}
func (mp *modeProcessor) doList(list *[]string, listMsg, endMsg int) {
target := mp.nextParam()
if target == "" {
if mp.adding {
ircSendChannelList(mp.c, mp.ch.name, *list, listMsg, endMsg)
}
return
}
if !mp.checkOperator() {
return
}
mask := ircCheckExpandUserMask(target)
if mask == "" {
return
}
var i int
for i = 0; i < len(*list); i++ {
if ircEqual((*list)[i], mask) {
break
}
}
found := i < len(*list)
if found != mp.adding {
if mp.adding {
*list = append(*list, mask)
} else {
*list = append((*list)[:i], (*list)[i+1:]...)
}
*mp.output = append(*mp.output, mp.modeChar)
*mp.outputParams = append(*mp.outputParams, mask)
}
}
func (mp *modeProcessor) doKey() {
target := mp.nextParam()
if !mp.checkOperator() || target == "" {
return
}
if !mp.adding {
if mp.ch.key == "" || !ircEqual(target, mp.ch.key) {
return
}
mp.removed = append(mp.removed, mp.modeChar)
mp.removedParams = append(mp.removedParams, mp.ch.key)
mp.ch.key = ""
} else if !ircIsValidKey(target) {
// TODO: We should notify the user somehow.
return
} else if mp.ch.key != "" {
mp.c.sendReply(ERR_KEYSET, mp.ch.name)
} else {
mp.ch.key = target
mp.added = append(mp.added, mp.modeChar)
mp.addedParams = append(mp.addedParams, mp.ch.key)
}
}
func (mp *modeProcessor) doLimit() {
if !mp.checkOperator() {
return
}
if !mp.adding {
if mp.ch.userLimit == -1 {
return
}
mp.ch.userLimit = -1
mp.removed = append(mp.removed, mp.modeChar)
} else if target := mp.nextParam(); target != "" {
if x, err := strconv.ParseInt(target, 10, 32); err == nil && x > 0 {
mp.ch.userLimit = int(x)
mp.added = append(mp.added, mp.modeChar)
mp.addedParams = append(mp.addedParams, target)
}
}
}
func (mp *modeProcessor) step(modeChar byte) bool {
mp.modeChar = modeChar
switch mp.modeChar {
case '+':
mp.adding = true
mp.output = &mp.added
mp.outputParams = &mp.addedParams
case '-':
mp.adding = false
mp.output = &mp.removed
mp.outputParams = &mp.removedParams
case 'o':
mp.doUser(ircChanModeOperator)
case 'v':
mp.doUser(ircChanModeVoice)
case 'i':
mp.doChan(ircChanModeInviteOnly)
case 'm':
mp.doChan(ircChanModeModerated)
case 'n':
mp.doChan(ircChanModeNoOutsideMsgs)
case 'q':
mp.doChan(ircChanModeQuiet)
case 't':
mp.doChan(ircChanModeProtectedTopic)
case 'p':
if mp.doChan(ircChanModePrivate) {
mp.doChanRemove('s', ircChanModeSecret)
}
case 's':
if mp.doChan(ircChanModeSecret) {
mp.doChanRemove('p', ircChanModePrivate)
}
case 'b':
mp.doList(&mp.ch.banList, RPL_BANLIST, RPL_ENDOFBANLIST)
case 'e':
mp.doList(&mp.ch.banList, RPL_EXCEPTLIST, RPL_ENDOFEXCEPTLIST)
case 'I':
mp.doList(&mp.ch.banList, RPL_INVITELIST, RPL_ENDOFINVITELIST)
case 'k':
mp.doKey()
case 'l':
mp.doLimit()
default:
// It's not safe to continue, results could be undesired.
mp.c.sendReply(ERR_UNKNOWNMODE, modeChar, mp.ch.name)
return false
}
return true
}
func ircHandleChanModeChange(c *client, ch *channel, params []string) {
modes, present := ch.userModes[c]
mp := &modeProcessor{
c: c,
ch: ch,
present: present,
modes: modes,
params: params,
}
Outer:
for {
modeString := mp.nextParam()
if modeString == "" {
break
}
mp.step('+')
for _, modeChar := range []byte(modeString) {
if !mp.step(modeChar) {
break Outer
}
}
}
// TODO: Limit to three changes with parameter per command.
if len(mp.added) > 0 || len(mp.removed) > 0 {
buf := []byte(fmt.Sprintf(":%s!%s@%s MODE %s ",
mp.c.nickname, mp.c.username, mp.c.hostname, mp.ch.name))
if len(mp.added) > 0 {
buf = append(buf, '+')
buf = append(buf, mp.added...)
}
if len(mp.removed) > 0 {
buf = append(buf, '-')
buf = append(buf, mp.removed...)
}
for _, param := range mp.addedParams {
buf = append(buf, ' ')
buf = append(buf, param...)
}
for _, param := range mp.removedParams {
buf = append(buf, ' ')
buf = append(buf, param...)
}
ircChannelMulticast(mp.ch, string(buf), nil)
}
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
func ircHandleMODE(msg *message, c *client) {
if len(msg.params) < 1 {
c.sendReply(ERR_NEEDMOREPARAMS, msg.command)
return
}
target := msg.params[0]
client := users[ircToCanon(target)]
ch := channels[ircToCanon(target)]
if client != nil {
if !ircEqual(target, c.nickname) {
c.sendReply(ERR_USERSDONTMATCH)
return
}
if len(msg.params) < 2 {
c.sendReply(RPL_UMODEIS, c.getMode())
} else {
ircHandleUserModeChange(c, msg.params[1])
}
} else if ch != nil {
if len(msg.params) < 2 {
_, present := ch.userModes[c]
c.sendReply(RPL_CHANNELMODEIS, target, ch.getMode(present))
c.sendReply(RPL_CREATIONTIME, target, ch.created.Unix())
} else {
ircHandleChanModeChange(c, ch, msg.params[1:])
}
} else {
c.sendReply(ERR_NOSUCHNICK, target)
}
}
func ircHandleUserMessage(msg *message, c *client,
command string, allowAwayReply bool) {
if len(msg.params) < 1 {
c.sendReply(ERR_NORECIPIENT, msg.command)
return
}
if len(msg.params) < 2 || msg.params[1] == "" {
c.sendReply(ERR_NOTEXTTOSEND)
return
}
target, text := msg.params[0], msg.params[1]
message := fmt.Sprintf(":%s!%s@%s %s %s :%s",
c.nickname, c.username, c.hostname, command, target, text)
if client := users[ircToCanon(target)]; client != nil {
client.send(message)
if allowAwayReply && client.awayMessage != "" {
c.sendReply(RPL_AWAY, target, client.awayMessage)
}
// Acknowledging a message from the client to itself would be silly.
if client != c && (0 != c.capsEnabled&ircCapEchoMessage) {
c.send(message)
}
} else if ch := channels[ircToCanon(target)]; ch != nil {
modes, present := ch.userModes[c]
outsider := !present && 0 != ch.modes&ircChanModeNoOutsideMsgs
moderated := 0 != ch.modes&ircChanModeModerated &&
0 == modes&(ircChanModeVoice|ircChanModeOperator)
banned := c.inMaskList(ch.banList) && !c.inMaskList(ch.exceptionList)
if outsider || moderated || banned {
c.sendReply(ERR_CANNOTSENDTOCHAN, target)
return
}
except := c
if 0 != c.capsEnabled&ircCapEchoMessage {
except = nil
}
ircChannelMulticast(ch, message, except)
} else {
c.sendReply(ERR_NOSUCHNICK, target)
}
}
func ircHandlePRIVMSG(msg *message, c *client) {
ircHandleUserMessage(msg, c, "PRIVMSG", true /* allowAwayReply */)
c.lastActive = time.Now()
}
func ircHandleNOTICE(msg *message, c *client) {
ircHandleUserMessage(msg, c, "NOTICE", false /* allowAwayReply */)
}
func ircHandleLIST(msg *message, c *client) {
if len(msg.params) > 1 && !ircIsThisMe(msg.params[1]) {
c.sendReply(ERR_NOSUCHSERVER, msg.params[1])
return
}
// XXX: Maybe we should skip ircUserModeInvisible from user counts.
if len(msg.params) == 0 {
for _, ch := range channels {
if _, present := ch.userModes[c]; present ||
0 == ch.modes&(ircChanModePrivate|ircChanModeSecret) {
c.sendReply(RPL_LIST, ch.name, len(ch.userModes), ch.topic)
}
}
} else {
for _, target := range splitString(msg.params[0], ",", true) {
if ch := channels[ircToCanon(target)]; ch != nil &&
0 == ch.modes&ircChanModeSecret {
c.sendReply(RPL_LIST, ch.name, len(ch.userModes), ch.topic)
}
}
}
c.sendReply(RPL_LISTEND)
}
func ircAppendPrefixes(c *client, modes uint, buf []byte) []byte {
var all []byte
if 0 != modes&ircChanModeOperator {
all = append(all, '@')
}
if 0 != modes&ircChanModeVoice {
all = append(all, '+')
}
if len(all) > 0 {
if 0 != c.capsEnabled&ircCapMultiPrefix {
buf = append(buf, all...)
} else {
buf = append(buf, all[0])
}
}
return buf
}
func ircMakeRPLNAMREPLYItem(c, target *client, modes uint) string {
result := string(ircAppendPrefixes(c, modes, nil)) + target.nickname
if 0 != c.capsEnabled&ircCapUserhostInNames {
result += fmt.Sprintf("!%s@%s", target.username, target.hostname)
}
return result
}
func ircSendRPLNAMREPLY(c *client, ch *channel, usedNicks map[*client]bool) {
kind := '='
if 0 != ch.modes&ircChanModeSecret {
kind = '@'
} else if 0 != ch.modes&ircChanModePrivate {
kind = '*'
}
_, present := ch.userModes[c]
var nicks []string
for client, modes := range ch.userModes {
if !present && 0 != client.mode&ircUserModeInvisible {
continue
}
if usedNicks != nil {
usedNicks[client] = true
}
nicks = append(nicks, ircMakeRPLNAMREPLYItem(c, client, modes))
}
c.sendReplyVector(RPL_NAMREPLY, nicks, kind, ch.name, "")
}
func ircSendDisassociatedNames(c *client, usedNicks map[*client]bool) {
var nicks []string
for _, client := range users {
if 0 == client.mode&ircUserModeInvisible && !usedNicks[client] {
nicks = append(nicks, ircMakeRPLNAMREPLYItem(c, client, 0))
}
}
if len(nicks) > 0 {
c.sendReplyVector(RPL_NAMREPLY, nicks, '*', "*", "")
}
}
func ircHandleNAMES(msg *message, c *client) {
if len(msg.params) > 1 && !ircIsThisMe(msg.params[1]) {
c.sendReply(ERR_NOSUCHSERVER, msg.params[1])
return
}
if len(msg.params) == 0 {
usedNicks := make(map[*client]bool)
for _, ch := range channels {
if _, present := ch.userModes[c]; present ||
0 == ch.modes&(ircChanModePrivate|ircChanModeSecret) {
ircSendRPLNAMREPLY(c, ch, usedNicks)
}
}
// Also send all visible users we haven't listed yet.
ircSendDisassociatedNames(c, usedNicks)
c.sendReply(RPL_ENDOFNAMES, "*")
} else {
for _, target := range splitString(msg.params[0], ",", true) {
if ch := channels[ircToCanon(target)]; ch == nil {
} else if _, present := ch.userModes[c]; present ||
0 == ch.modes&ircChanModeSecret {
ircSendRPLNAMREPLY(c, ch, nil)
c.sendReply(RPL_ENDOFNAMES, target)
}
}
}
}
func ircSendRPLWHOREPLY(c *client, ch *channel, target *client) {
var chars []byte
if target.awayMessage != "" {
chars = append(chars, 'G')
} else {
chars = append(chars, 'H')
}
if 0 != target.mode&ircUserModeOperator {
chars = append(chars, '*')
}
channelName := "*"
if ch != nil {
channelName = ch.name
if modes, present := ch.userModes[target]; present {
chars = ircAppendPrefixes(c, modes, chars)
}
}
c.sendReply(RPL_WHOREPLY, channelName,
target.username, target.hostname, serverName,
target.nickname, string(chars), 0 /* hop count */, target.realname)
}
func ircMatchSendRPLWHOREPLY(c, target *client, mask string) {
isRoommate := false
for _, ch := range channels {
_, presentClient := ch.userModes[c]
_, presentTarget := ch.userModes[target]
if presentClient && presentTarget {
isRoommate = true
break
}
}
if !isRoommate && 0 != target.mode&ircUserModeInvisible {
return
}
if !ircFnmatch(mask, target.hostname) &&
!ircFnmatch(mask, target.nickname) &&
!ircFnmatch(mask, target.realname) &&
!ircFnmatch(mask, serverName) {
return
}
// Try to find a channel they're on that's visible to us.
var userCh *channel
for _, ch := range channels {
_, presentClient := ch.userModes[c]
_, presentTarget := ch.userModes[target]
if presentTarget && (presentClient ||
0 == ch.modes&(ircChanModePrivate|ircChanModeSecret)) {
userCh = ch
break
}
}
ircSendRPLWHOREPLY(c, userCh, target)
}
func ircHandleWHO(msg *message, c *client) {
onlyOps := len(msg.params) > 1 && msg.params[1] == "o"
shownMask, usedMask := "*", "*"
if len(msg.params) > 0 {
shownMask = msg.params[0]
if shownMask != "0" {
usedMask = shownMask
}
}
if ch := channels[ircToCanon(usedMask)]; ch != nil {
_, present := ch.userModes[c]
if present || 0 == ch.modes&ircChanModeSecret {
for client := range ch.userModes {
if (present || 0 == client.mode&ircUserModeInvisible) &&
(!onlyOps || 0 != client.mode&ircUserModeOperator) {
ircSendRPLWHOREPLY(c, ch, client)
}
}
}
} else {
for _, client := range users {
if !onlyOps || 0 != client.mode&ircUserModeOperator {
ircMatchSendRPLWHOREPLY(c, client, usedMask)
}
}
}
c.sendReply(RPL_ENDOFWHO, shownMask)
}
func ircSendWHOISReply(c, target *client) {
nick := target.nickname
c.sendReply(RPL_WHOISUSER, nick,
target.username, target.hostname, target.realname)
c.sendReply(RPL_WHOISSERVER, nick, serverName, config["server_info"])
if 0 != target.mode&ircUserModeOperator {
c.sendReply(RPL_WHOISOPERATOR, nick)
}
c.sendReply(RPL_WHOISIDLE, nick,
time.Now().Sub(target.lastActive)/time.Second)
if target.awayMessage != "" {
c.sendReply(RPL_AWAY, nick, target.awayMessage)
}
var chans []string
for _, ch := range channels {
_, presentClient := ch.userModes[c]
modes, presentTarget := ch.userModes[target]
if presentTarget && (presentClient ||
0 == ch.modes&(ircChanModePrivate|ircChanModeSecret)) {
// TODO: Deduplicate, ircAppendPrefixes just also cuts prefixes.
var all []byte
if 0 != modes&ircChanModeOperator {
all = append(all, '@')
}
if 0 != modes&ircChanModeVoice {
all = append(all, '+')
}
chans = append(chans, string(all)+ch.name)
}
}
c.sendReplyVector(RPL_WHOISCHANNELS, chans, nick, "")
c.sendReply(RPL_ENDOFWHOIS, nick)
}
func ircHandleWHOIS(msg *message, c *client) {
if len(msg.params) < 1 {
c.sendReply(ERR_NEEDMOREPARAMS, msg.command)
return
}
if len(msg.params) > 1 && !ircIsThisMe(msg.params[0]) {
c.sendReply(ERR_NOSUCHSERVER, msg.params[0])
return
}
masksStr := msg.params[0]
if len(msg.params) > 1 {
masksStr = msg.params[1]
}
for _, mask := range splitString(masksStr, ",", true /* ignoreEmpty */) {
if strings.IndexAny(mask, "*?") < 0 {
if target := users[ircToCanon(mask)]; target == nil {
c.sendReply(ERR_NOSUCHNICK, mask)
} else {
ircSendWHOISReply(c, target)
}
} else {
found := false
for _, target := range users {
if ircFnmatch(mask, target.nickname) {
ircSendWHOISReply(c, target)
found = true
}
}
if !found {
c.sendReply(ERR_NOSUCHNICK, mask)
}
}
}
}
func ircHandleWHOWAS(msg *message, c *client) {
if len(msg.params) < 1 {
c.sendReply(ERR_NEEDMOREPARAMS, msg.command)
return
}
if len(msg.params) > 2 && !ircIsThisMe(msg.params[2]) {
c.sendReply(ERR_NOSUCHSERVER, msg.params[2])
return
}
// The "count" parameter is ignored, we only store one entry for a nick.
for _, nick := range splitString(msg.params[0], ",", true) {
if info := whowas[ircToCanon(nick)]; info == nil {
c.sendReply(ERR_WASNOSUCHNICK, nick)
} else {
c.sendReply(RPL_WHOWASUSER, nick,
info.username, info.hostname, info.realname)
c.sendReply(RPL_WHOISSERVER, nick,
serverName, config["server_info"])
}
c.sendReply(RPL_ENDOFWHOWAS, nick)
}
}
func ircSendRPLTOPIC(c *client, ch *channel) {
if ch.topic == "" {
c.sendReply(RPL_NOTOPIC, ch.name)
} else {
c.sendReply(RPL_TOPIC, ch.name, ch.topic)
c.sendReply(RPL_TOPICWHOTIME,
ch.name, ch.topicWho, ch.topicTime.Unix())
}
}
func ircHandleTOPIC(msg *message, c *client) {
if len(msg.params) < 1 {
c.sendReply(ERR_NEEDMOREPARAMS, msg.command)
return
}
channelName := msg.params[0]
ch := channels[ircToCanon(channelName)]
if ch == nil {
c.sendReply(ERR_NOSUCHCHANNEL, channelName)
return
}
if len(msg.params) < 2 {
ircSendRPLTOPIC(c, ch)
return
}
modes, present := ch.userModes[c]
if !present {
c.sendReply(ERR_NOTONCHANNEL, channelName)
return
}
if 0 != ch.modes&ircChanModeProtectedTopic &&
0 == modes&ircChanModeOperator {
c.sendReply(ERR_CHANOPRIVSNEEDED, channelName)
return
}
ch.topic = msg.params[1]
ch.topicWho = fmt.Sprintf("%s@%s@%s", c.nickname, c.username, c.hostname)
ch.topicTime = time.Now()
message := fmt.Sprintf(":%s!%s@%s TOPIC %s :%s",
c.nickname, c.username, c.hostname, channelName, ch.topic)
ircChannelMulticast(ch, message, nil)
}
func ircTryPart(c *client, channelName string, reason string) {
if reason == "" {
reason = c.nickname
}
ch := channels[ircToCanon(channelName)]
if ch == nil {
c.sendReply(ERR_NOSUCHCHANNEL, channelName)
return
}
if _, present := ch.userModes[c]; !present {
c.sendReply(ERR_NOTONCHANNEL, channelName)
return
}
message := fmt.Sprintf(":%s@%s@%s PART %s :%s",
c.nickname, c.username, c.hostname, channelName, reason)
if 0 == ch.modes&ircChanModeQuiet {
ircChannelMulticast(ch, message, nil)
} else {
c.send(message)
}
delete(ch.userModes, c)
ircChannelDestroyIfEmpty(ch)
}
func ircPartAllChannels(c *client) {
for _, ch := range channels {
if _, present := ch.userModes[c]; present {
ircTryPart(c, ch.name, "")
}
}
}
func ircHandlePART(msg *message, c *client) {
if len(msg.params) < 1 {
c.sendReply(ERR_NEEDMOREPARAMS, msg.command)
return
}
reason := ""
if len(msg.params) > 1 {
reason = msg.params[1]
}
for _, channelName := range splitString(msg.params[0], ",", true) {
ircTryPart(c, channelName, reason)
}
}
func ircTryKick(c *client, channelName, nick, reason string) {
ch := channels[ircToCanon(channelName)]
if ch == nil {
c.sendReply(ERR_NOSUCHCHANNEL, channelName)
return
}
if modes, present := ch.userModes[c]; !present {
c.sendReply(ERR_NOTONCHANNEL, channelName)
return
} else if 0 == modes&ircChanModeOperator {
c.sendReply(ERR_CHANOPRIVSNEEDED, channelName)
return
}
client := users[ircToCanon(nick)]
if _, present := ch.userModes[client]; client == nil || !present {
c.sendReply(ERR_USERNOTINCHANNEL, nick, channelName)
return
}
message := fmt.Sprintf(":%s@%s@%s KICK %s %s :%s",
c.nickname, c.username, c.hostname, channelName, nick, reason)
if 0 == ch.modes&ircChanModeQuiet {
ircChannelMulticast(ch, message, nil)
} else {
c.send(message)
}
delete(ch.userModes, client)
ircChannelDestroyIfEmpty(ch)
}
func ircHandleKICK(msg *message, c *client) {
if len(msg.params) < 2 {
c.sendReply(ERR_NEEDMOREPARAMS, msg.command)
return
}
reason := c.nickname
if len(msg.params) > 2 {
reason = msg.params[2]
}
targetChannels := splitString(msg.params[0], ",", true)
targetUsers := splitString(msg.params[1], ",", true)
if len(channels) == 1 {
for i := 0; i < len(targetUsers); i++ {
ircTryKick(c, targetChannels[0], targetUsers[i], reason)
}
} else {
for i := 0; i < len(channels) && i < len(targetUsers); i++ {
ircTryKick(c, targetChannels[i], targetUsers[i], reason)
}
}
}
func ircSendInviteNotifications(ch *channel, c, target *client) {
for client := range ch.userModes {
if client != target && 0 != client.capsEnabled&ircCapInviteNotify {
client.sendf(":%s!%s@%s INVITE %s %s",
c.nickname, c.username, c.hostname, target.nickname, ch.name)
}
}
}
func ircHandleINVITE(msg *message, c *client) {
if len(msg.params) < 2 {
c.sendReply(ERR_NEEDMOREPARAMS, msg.command)
return
}
target, channelName := msg.params[0], msg.params[1]
client := users[ircToCanon(target)]
if client == nil {
c.sendReply(ERR_NOSUCHNICK, target)
return
}
if ch := channels[ircToCanon(channelName)]; ch != nil {
invitingModes, invitingPresent := ch.userModes[c]
if !invitingPresent {
c.sendReply(ERR_NOTONCHANNEL, channelName)
return
}
if _, present := ch.userModes[client]; present {
c.sendReply(ERR_USERONCHANNEL, target, channelName)
return
}
if 0 != invitingModes&ircChanModeOperator {
client.invites[ircToCanon(channelName)] = true
} else if 0 != ch.modes&ircChanModeInviteOnly {
c.sendReply(ERR_CHANOPRIVSNEEDED, channelName)
return
}
// It's not specified when and how we should send out invite-notify.
if 0 != ch.modes&ircChanModeInviteOnly {
ircSendInviteNotifications(ch, c, client)
}
}
client.sendf(":%s!%s@%s INVITE %s %s",
c.nickname, c.username, c.hostname, client.nickname, channelName)
if client.awayMessage != "" {
c.sendReply(RPL_AWAY, client.nickname, client.awayMessage)
}
c.sendReply(RPL_INVITING, client.nickname, channelName)
}
func ircTryJoin(c *client, channelName, key string) {
ch := channels[ircToCanon(channelName)]
var userMode uint
if ch == nil {
if !ircIsValidChannelName(channelName) {
c.sendReply(ERR_BADCHANMASK, channelName)
return
}
ch = ircChannelCreate(channelName)
userMode = ircChanModeOperator
} else if _, present := ch.userModes[c]; present {
return
}
_, invitedByChanop := c.invites[ircToCanon(channelName)]
if 0 != ch.modes&ircChanModeInviteOnly && c.inMaskList(ch.inviteList) &&
!invitedByChanop {
c.sendReply(ERR_INVITEONLYCHAN, channelName)
return
}
if ch.key != "" && (key == "" || key != ch.key) {
c.sendReply(ERR_BADCHANNELKEY, channelName)
return
}
if ch.userLimit != -1 && len(ch.userModes) >= ch.userLimit {
c.sendReply(ERR_CHANNELISFULL, channelName)
return
}
if c.inMaskList(ch.banList) && !c.inMaskList(ch.exceptionList) &&
!invitedByChanop {
c.sendReply(ERR_BANNEDFROMCHAN, channelName)
return
}
// Destroy any invitation as there's no other way to get rid of it.
delete(c.invites, ircToCanon(channelName))
ch.userModes[c] = userMode
message := fmt.Sprintf(":%s!%s@%s JOIN %s",
c.nickname, c.username, c.hostname, channelName)
if 0 == ch.modes&ircChanModeQuiet {
ircChannelMulticast(ch, message, nil)
} else {
c.send(message)
}
ircSendRPLTOPIC(c, ch)
ircSendRPLNAMREPLY(c, ch, nil)
c.sendReply(RPL_ENDOFNAMES, ch.name)
}
func ircHandleJOIN(msg *message, c *client) {
if len(msg.params) < 1 {
c.sendReply(ERR_NEEDMOREPARAMS, msg.command)
return
}
if msg.params[0] == "0" {
ircPartAllChannels(c)
return
}
targetChannels := splitString(msg.params[0], ",", true)
var keys []string
if len(msg.params) > 1 {
keys = splitString(msg.params[1], ",", true)
}
for i, name := range targetChannels {
key := ""
if i < len(keys) {
key = keys[i]
}
ircTryJoin(c, name, key)
}
}
func ircHandleSUMMON(msg *message, c *client) {
c.sendReply(ERR_SUMMONDISABLED)
}
func ircHandleUSERS(msg *message, c *client) {
c.sendReply(ERR_USERSDISABLED)
}
func ircHandleAWAY(msg *message, c *client) {
if len(msg.params) < 1 {
c.awayMessage = ""
c.sendReply(RPL_UNAWAY)
} else {
c.awayMessage = msg.params[0]
c.sendReply(RPL_NOWAWAY)
}
}
func ircHandleISON(msg *message, c *client) {
if len(msg.params) < 1 {
c.sendReply(ERR_NEEDMOREPARAMS, msg.command)
return
}
var on []string
for _, nick := range msg.params {
if client := users[ircToCanon(nick)]; client != nil {
on = append(on, nick)
}
}
c.sendReply(RPL_ISON, strings.Join(on, " "))
}
func ircHandleADMIN(msg *message, c *client) {
if len(msg.params) > 0 && !ircIsThisMe(msg.params[0]) {
c.sendReply(ERR_NOSUCHSERVER, msg.params[0])
return
}
c.sendReply(ERR_NOADMININFO, serverName)
}
func ircHandleStatsLinks(c *client, msg *message) {
// There is only an "l" query in RFC 2812 but we cannot link,
// so instead we provide the "L" query giving information for all users.
filter := ""
if len(msg.params) > 1 {
filter = msg.params[1]
}
for _, client := range users {
if filter != "" && !ircEqual(client.nickname, filter) {
continue
}
c.sendReply(RPL_STATSLINKINFO,
client.address, // linkname
len(client.sendQ), // sendq
client.nSentMessages, client.sentBytes/1024,
client.nReceivedMessages, client.receivedBytes/1024,
time.Now().Sub(client.opened)/time.Second)
}
}
func ircHandleStatsCommands(c *client) {
for name, handler := range ircHandlers {
if handler.nReceived > 0 {
c.sendReply(RPL_STATSCOMMANDS, name,
handler.nReceived, handler.bytesReceived, 0)
}
}
}
// We need to do it this way because of an initialization loop concerning
// ircHandlers. Workaround proposed by rsc in go #1817.
var ircHandleStatsCommandsIndirect func(c *client)
func init() {
ircHandleStatsCommandsIndirect = ircHandleStatsCommands
}
func ircHandleStatsUptime(c *client) {
uptime := time.Now().Sub(started) / time.Second
days := uptime / 60 / 60 / 24
hours := (uptime % (60 * 60 * 24)) / 60 / 60
mins := (uptime % (60 * 60)) / 60
secs := uptime % 60
c.sendReply(RPL_STATSUPTIME, days, hours, mins, secs)
}
func ircHandleSTATS(msg *message, c *client) {
var query byte
if len(msg.params) > 0 && len(msg.params[0]) > 0 {
query = msg.params[0][0]
}
if len(msg.params) > 1 && !ircIsThisMe(msg.params[1]) {
c.sendReply(ERR_NOSUCHSERVER, msg.params[0])
return
}
if 0 == c.mode&ircUserModeOperator {
c.sendReply(ERR_NOPRIVILEGES)
return
}
switch query {
case 'L':
ircHandleStatsLinks(c, msg)
case 'm':
ircHandleStatsCommandsIndirect(c)
case 'u':
ircHandleStatsUptime(c)
}
c.sendReply(RPL_ENDOFSTATS, query)
}
func ircHandleLINKS(msg *message, c *client) {
if len(msg.params) > 1 && !ircIsThisMe(msg.params[0]) {
c.sendReply(ERR_NEEDMOREPARAMS, msg.command)
return
}
mask := "*"
if len(msg.params) > 0 {
if len(msg.params) > 1 {
mask = msg.params[1]
} else {
mask = msg.params[0]
}
}
if ircFnmatch(mask, serverName) {
c.sendReply(RPL_LINKS, mask, serverName,
0 /* hop count */, config["server_info"])
}
c.sendReply(RPL_ENDOFLINKS, mask)
}
func ircHandleWALLOPS(msg *message, c *client) {
if len(msg.params) < 1 {
c.sendReply(ERR_NEEDMOREPARAMS, msg.command)
return
}
if 0 == c.mode&ircUserModeOperator {
c.sendReply(ERR_NOPRIVILEGES)
return
}
// Our interpretation: anonymize the sender,
// and target all users who want to receive these messages.
for _, client := range users {
if client == c || 0 != client.mode&ircUserModeRxWallops {
client.sendf(":%s WALLOPS :%s", serverName, msg.params[0])
}
}
}
func ircHandleKILL(msg *message, c *client) {
if len(msg.params) < 2 {
c.sendReply(ERR_NEEDMOREPARAMS, msg.command)
return
}
if 0 == c.mode&ircUserModeOperator {
c.sendReply(ERR_NOPRIVILEGES)
return
}
target := users[ircToCanon(msg.params[0])]
if target == nil {
c.sendReply(ERR_NOSUCHNICK, msg.params[0])
return
}
c.sendf(":%s!%s@%s KILL %s :%s",
c.nickname, c.username, c.hostname, target.nickname, msg.params[1])
target.closeLink(fmt.Sprintf("Killed by %s: %s", c.nickname, msg.params[1]))
}
func ircHandleDIE(msg *message, c *client) {
if 0 == c.mode&ircUserModeOperator {
c.sendReply(ERR_NOPRIVILEGES)
} else if !quitting {
initiateQuit()
}
}
// -----------------------------------------------------------------------------
// TODO: Add an index for ERR_NOSUCHSERVER validation?
// TODO: Add a minimal parameter count?
// TODO: Add a field for oper-only commands? Use flags?
var ircHandlers = map[string]*ircCommand{
"WEBIRC": {false, ircHandleWEBIRC, 0, 0},
"CAP": {false, ircHandleCAP, 0, 0},
"PASS": {false, ircHandlePASS, 0, 0},
"NICK": {false, ircHandleNICK, 0, 0},
"USER": {false, ircHandleUSER, 0, 0},
"USERHOST": {true, ircHandleUSERHOST, 0, 0},
"LUSERS": {true, ircHandleLUSERS, 0, 0},
"MOTD": {true, ircHandleMOTD, 0, 0},
"PING": {true, ircHandlePING, 0, 0},
"PONG": {false, ircHandlePONG, 0, 0},
"QUIT": {false, ircHandleQUIT, 0, 0},
"TIME": {true, ircHandleTIME, 0, 0},
"VERSION": {true, ircHandleVERSION, 0, 0},
"USERS": {true, ircHandleUSERS, 0, 0},
"SUMMON": {true, ircHandleSUMMON, 0, 0},
"AWAY": {true, ircHandleAWAY, 0, 0},
"ADMIN": {true, ircHandleADMIN, 0, 0},
"STATS": {true, ircHandleSTATS, 0, 0},
"LINKS": {true, ircHandleLINKS, 0, 0},
"WALLOPS": {true, ircHandleWALLOPS, 0, 0},
"MODE": {true, ircHandleMODE, 0, 0},
"PRIVMSG": {true, ircHandlePRIVMSG, 0, 0},
"NOTICE": {true, ircHandleNOTICE, 0, 0},
"JOIN": {true, ircHandleJOIN, 0, 0},
"PART": {true, ircHandlePART, 0, 0},
"KICK": {true, ircHandleKICK, 0, 0},
"INVITE": {true, ircHandleINVITE, 0, 0},
"TOPIC": {true, ircHandleTOPIC, 0, 0},
"LIST": {true, ircHandleLIST, 0, 0},
"NAMES": {true, ircHandleNAMES, 0, 0},
"WHO": {true, ircHandleWHO, 0, 0},
"WHOIS": {true, ircHandleWHOIS, 0, 0},
"WHOWAS": {true, ircHandleWHOWAS, 0, 0},
"ISON": {true, ircHandleISON, 0, 0},
"KILL": {true, ircHandleKILL, 0, 0},
"DIE": {true, ircHandleDIE, 0, 0},
}
func ircProcessMessage(c *client, msg *message, raw string) {
if c.closing {
return
}
c.nReceivedMessages++
c.receivedBytes += len(raw) + 2
if !c.antiflood.check() {
c.closeLink("Excess flood")
return
}
if cmd, ok := ircHandlers[ircToCanon(msg.command)]; !ok {
c.sendReply(ERR_UNKNOWNCOMMAND, msg.command)
} else {
cmd.nReceived++
cmd.bytesReceived += len(raw) + 2
if cmd.requiresRegistration && !c.registered {
c.sendReply(ERR_NOTREGISTERED)
} else {
cmd.handler(msg, c)
}
}
}
// --- Network I/O -------------------------------------------------------------
// Handle the results from initializing the client's connection.
func (c *client) onPrepared(host string, isTLS bool) {
c.printDebug("client resolved to %s, TLS %t", host, isTLS)
if !isTLS {
c.conn = c.transport.(connCloseWriter)
} else if tlsConf != nil {
c.tls = tls.Server(c.transport, tlsConf)
c.conn = c.tls
} else {
c.printDebug("could not initialize TLS: disabled")
c.kill("TLS support disabled")
return
}
c.hostname = host
c.address = net.JoinHostPort(host, c.port)
// If we tried to send any data before now, we would need to flushSendQ.
go read(c)
c.reading = true
c.setPingTimer()
}
// Handle the results from trying to read from the client connection.
func (c *client) onRead(data []byte, readErr error) {
if !c.reading {
// Abusing the flag to emulate CloseRead and skip over data, see below.
return
}
c.recvQ = append(c.recvQ, data...)
for {
// XXX: This accepts even simple LF newlines, even though they're not
// really allowed by the protocol.
advance, token, _ := bufio.ScanLines(c.recvQ, false /* atEOF */)
if advance == 0 {
break
}
// XXX: And since it accepts LF, we miscalculate receivedBytes within.
c.recvQ = c.recvQ[advance:]
line := string(token)
c.printDebug("-> %s", line)
if msg := ircParseMessage(line); msg == nil {
c.printDebug("error: invalid line")
} else {
ircProcessMessage(c, msg, line)
}
}
if readErr != nil {
c.reading = false
if readErr != io.EOF {
c.printDebug("%s", readErr)
c.kill(readErr.Error())
} else if c.closing {
// Disregarding whether a clean shutdown has happened or not.
c.printDebug("client finished shutdown")
c.kill("")
} else {
c.printDebug("client EOF")
c.closeLink("")
}
} else if len(c.recvQ) > 8192 {
c.closeLink("recvQ overrun")
// tls.Conn doesn't have the CloseRead method (and it needs to be able
// to read from the TCP connection even for writes, so there isn't much
// sense in expecting the implementation to do anything useful),
// otherwise we'd use it to block incoming packet data.
c.reading = false
}
}
// Spawn a goroutine to flush the sendQ if possible and necessary.
func (c *client) flushSendQ() {
if !c.writing && c.conn != nil {
go write(c, c.sendQ)
c.writing = true
}
}
// Handle the results from trying to write to the client connection.
func (c *client) onWrite(written int, writeErr error) {
c.sendQ = c.sendQ[written:]
c.writing = false
if writeErr != nil {
c.printDebug("%s", writeErr)
c.kill(writeErr.Error())
} else if len(c.sendQ) > 0 {
c.flushSendQ()
} else if c.closing {
if c.reading {
c.conn.CloseWrite()
} else {
c.kill("")
}
}
}
// --- Worker goroutines -------------------------------------------------------
func accept(ln net.Listener) {
for {
// Error handling here may be tricky, see go #6163, #24808.
if conn, err := ln.Accept(); err != nil {
// See go #4373, they're being dicks. Another solution would be to
// pass a done channel to this function and close it before closing
// all the listeners, returning from here if it's readable.
if strings.Contains(err.Error(),
"use of closed network connection") {
return
}
// XXX: net.Error.Temporary() has been deprecated in 1.18.
if op, ok := err.(net.Error); !ok || !op.Temporary() {
exitFatal("%s", err)
} else {
printError("%s", err)
}
} else {
// TCP_NODELAY is set by default on TCPConns.
conns <- conn
}
}
}
func prepare(client *client) {
conn, host := client.transport, client.hostname
// The Cgo resolver doesn't pthread_cancel getnameinfo threads, so not
// bothering with pointless contexts.
ch := make(chan string, 1)
go func() {
defer close(ch)
if names, err := net.LookupAddr(host); err != nil {
printError("%s", err)
} else {
ch <- names[0]
}
}()
// While we can't cancel it, we still want to set a timeout on it.
select {
case <-time.After(5 * time.Second):
case resolved, ok := <-ch:
if ok {
host = resolved
}
}
// Note that in this demo application the autodetection prevents non-TLS
// clients from receiving any messages until they send something.
isTLS := false
if sysconn, err := conn.(syscall.Conn).SyscallConn(); err != nil {
// This is just for the TLS detection and doesn't need to be fatal.
printError("%s", err)
} else {
isTLS = detectTLS(sysconn)
}
prepared <- preparedEvent{client, host, isTLS}
}
func read(client *client) {
// A new buffer is allocated each time we receive some bytes, because of
// thread-safety. Therefore the buffer shouldn't be too large, or we'd
// need to copy it each time into a precisely sized new buffer.
var err error
for err == nil {
var (
buf [512]byte
n int
)
n, err = client.conn.Read(buf[:])
reads <- readEvent{client, buf[:n], err}
}
}
// Flush sendQ, which is passed by parameter so that there are no data races.
func write(client *client, data []byte) {
// We just write as much as we can, the main goroutine does the looping.
n, err := client.conn.Write(data)
writes <- writeEvent{client, n, err}
}
// --- Event loop --------------------------------------------------------------
func processOneEvent() {
select {
case <-sigs:
if quitting {
forceQuit("requested by user")
} else {
initiateQuit()
}
case <-quitTimer:
forceQuit("timeout")
case callback := <-timers:
callback()
case conn := <-conns:
if maxConnections > 0 && len(clients) >= maxConnections {
printDebug("connection limit reached, refusing connection")
conn.Close()
break
}
address := conn.RemoteAddr().String()
host, port, err := net.SplitHostPort(address)
if err != nil {
// In effect, we require TCP/UDP, as they have port numbers.
exitFatal("%s", err)
}
c := &client{
transport: conn,
address: address,
hostname: host,
port: port,
capVersion: 301,
opened: time.Now(),
lastActive: time.Now(),
// TODO: Make this configurable and more fine-grained.
antiflood: newFloodDetector(10*time.Second, 20),
}
clients[c] = true
c.printDebug("new client")
go prepare(c)
// The TLS autodetection in prepare needs to have a timeout.
c.setKillTimer()
case ev := <-prepared:
if _, ok := clients[ev.client]; ok {
ev.client.onPrepared(ev.host, ev.isTLS)
}
case ev := <-reads:
if _, ok := clients[ev.client]; ok {
ev.client.onRead(ev.data, ev.err)
}
case ev := <-writes:
if _, ok := clients[ev.client]; ok {
ev.client.onWrite(ev.written, ev.err)
}
}
}
// --- Application setup -------------------------------------------------------
func ircInitializeTLS() error {
configCert, configKey := config["tls_cert"], config["tls_key"]
// Only try to enable SSL support if the user configures it; it is not
// a failure if no one has requested it.
if configCert == "" && configKey == "" {
return nil
} else if configCert == "" {
return errors.New("no TLS certificate set")
} else if configKey == "" {
return errors.New("no TLS private key set")
}
pathCert := resolveFilename(configCert, resolveRelativeConfigFilename)
if pathCert == "" {
return fmt.Errorf("cannot find file: %s", configCert)
}
pathKey := resolveFilename(configKey, resolveRelativeConfigFilename)
if pathKey == "" {
return fmt.Errorf("cannot find file: %s", configKey)
}
cert, err := tls.LoadX509KeyPair(pathCert, pathKey)
if err != nil {
return err
}
tlsConf = &tls.Config{
Certificates: []tls.Certificate{cert},
ClientAuth: tls.RequestClientCert,
SessionTicketsDisabled: true,
}
return nil
}
func ircInitializeCatalog() error {
configCatalog := config["catalog"]
if configCatalog == "" {
return nil
}
path := resolveFilename(configCatalog, resolveRelativeConfigFilename)
if path == "" {
return fmt.Errorf("cannot find file: %s", configCatalog)
}
f, err := os.Open(path)
if err != nil {
return fmt.Errorf("failed reading the MOTD file: %s", err)
}
defer f.Close()
scanner := bufio.NewScanner(f)
catalog = make(map[int]string)
for lineNo := 1; scanner.Scan(); lineNo++ {
line := strings.TrimLeft(scanner.Text(), " \t")
if line == "" || strings.HasPrefix(line, "#") {
continue
}
delim := strings.IndexAny(line, " \t")
if delim < 0 {
return fmt.Errorf("%s:%d: malformed line", path, lineNo)
}
id, err := strconv.ParseUint(line[:delim], 10, 16)
if err != nil {
return fmt.Errorf("%s:%d: %s", path, lineNo, err)
}
catalog[int(id)] = line[delim+1:]
}
return scanner.Err()
}
func ircInitializeMOTD() error {
configMOTD := config["motd"]
if configMOTD == "" {
return nil
}
path := resolveFilename(configMOTD, resolveRelativeConfigFilename)
if path == "" {
return fmt.Errorf("cannot find file: %s", configMOTD)
}
f, err := os.Open(path)
if err != nil {
return fmt.Errorf("failed reading the MOTD file: %s", err)
}
defer f.Close()
scanner := bufio.NewScanner(f)
motd = nil
for scanner.Scan() {
motd = append(motd, scanner.Text())
}
return scanner.Err()
}
type configProcessor struct {
err error // any error that has occurred so far
}
func (cp *configProcessor) read(name string, process func(string) string) {
if cp.err != nil {
return
}
if err := process(config[name]); err != "" {
cp.err = fmt.Errorf("invalid configuration value for `%s': %s",
name, err)
}
}
// This function handles values that require validation before their first use,
// or some kind of a transformation (such as conversion to an integer) needs
// to be done before they can be used directly.
func ircParseConfig() error {
cp := &configProcessor{}
cp.read("ping_interval", func(value string) string {
if u, err := strconv.ParseUint(
config["ping_interval"], 10, 32); err != nil {
return err.Error()
} else if u < 1 {
return "the value is out of range"
} else {
pingInterval = time.Second * time.Duration(u)
}
return ""
})
cp.read("max_connections", func(value string) string {
if i, err := strconv.ParseInt(
value, 10, 32); err != nil {
return err.Error()
} else if i < 0 {
return "the value is out of range"
} else {
maxConnections = int(i)
}
return ""
})
cp.read("operators", func(value string) string {
operators = make(map[string]bool)
for _, fp := range splitString(value, ",", true) {
if !ircIsValidFingerprint(fp) {
return "invalid fingerprint value"
}
operators[strings.ToLower(fp)] = true
}
return ""
})
return cp.err
}
func ircInitializeServerName() error {
if value := config["server_name"]; value != "" {
if err := ircValidateHostname(value); err != nil {
return err
}
serverName = value
return nil
}
if hostname, err := os.Hostname(); err != nil {
return err
} else if err := ircValidateHostname(hostname); err != nil {
return err
} else {
serverName = hostname
}
return nil
}
func ircSetupListenFDs() error {
for _, address := range splitString(config["bind"], ",", true) {
ln, err := net.Listen("tcp", address)
if err != nil {
return err
}
listeners = append(listeners, ln)
printStatus("listening on %s", address)
}
if len(listeners) == 0 {
return errors.New("network setup failed: no ports to listen on")
}
for _, ln := range listeners {
go accept(ln)
}
return nil
}
// --- Main --------------------------------------------------------------------
func main() {
flag.BoolVar(&debugMode, "debug", false, "run in verbose debug mode")
version := flag.Bool("version", false, "show version and exit")
writeDefaultCfg := flag.Bool("writedefaultcfg", false,
"write a default configuration file and exit")
systemd := flag.Bool("systemd", false, "log in systemd format")
flag.Parse()
if *version {
fmt.Printf("%s %s\n", projectName, projectVersion)
return
}
if *writeDefaultCfg {
callSimpleConfigWriteDefault("", configTable)
return
}
if *systemd {
logMessage = logMessageSystemd
}
if flag.NArg() > 0 {
flag.Usage()
os.Exit(2)
}
// Note that this has become unnecessary since Go 1.19.
var limit syscall.Rlimit
if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err == nil &&
limit.Cur != limit.Max {
limit.Cur = limit.Max
syscall.Setrlimit(syscall.RLIMIT_NOFILE, &limit)
}
config = make(simpleConfig)
config.loadDefaults(configTable)
if err := config.updateFromFile(); err != nil && !os.IsNotExist(err) {
printError("error loading configuration: %s", err)
os.Exit(1)
}
started = time.Now()
signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
for _, fn := range []func() error{
ircInitializeTLS,
ircInitializeServerName,
ircInitializeMOTD,
ircInitializeCatalog,
ircParseConfig,
ircSetupListenFDs,
} {
if err := fn(); err != nil {
exitFatal("%s", err)
}
}
for !quitting || len(clients) > 0 {
processOneEvent()
}
}
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