soju/downstream.go

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package soju
import (
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"crypto/tls"
"fmt"
"io"
"net"
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"strings"
"sync"
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"time"
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"golang.org/x/crypto/bcrypt"
"gopkg.in/irc.v3"
)
type ircError struct {
Message *irc.Message
}
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func (err ircError) Error() string {
return err.Message.String()
}
func newUnknownCommandError(cmd string) ircError {
return ircError{&irc.Message{
Command: irc.ERR_UNKNOWNCOMMAND,
Params: []string{
"*",
cmd,
"Unknown command",
},
}}
}
func newNeedMoreParamsError(cmd string) ircError {
return ircError{&irc.Message{
Command: irc.ERR_NEEDMOREPARAMS,
Params: []string{
"*",
cmd,
"Not enough parameters",
},
}}
}
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var errAuthFailed = ircError{&irc.Message{
Command: irc.ERR_PASSWDMISMATCH,
Params: []string{"*", "Invalid username or password"},
}}
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type ringMessage struct {
consumer *RingConsumer
upstreamConn *upstreamConn
}
type downstreamConn struct {
net net.Conn
irc *irc.Conn
srv *Server
logger Logger
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outgoing chan *irc.Message
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ringMessages chan ringMessage
closed chan struct{}
registered bool
user *user
nick string
username string
rawUsername string
realname string
password string // empty after authentication
network *network // can be nil
lock sync.Mutex
ourMessages map[*irc.Message]struct{}
}
func newDownstreamConn(srv *Server, netConn net.Conn) *downstreamConn {
dc := &downstreamConn{
net: netConn,
irc: irc.NewConn(netConn),
srv: srv,
logger: &prefixLogger{srv.Logger, fmt.Sprintf("downstream %q: ", netConn.RemoteAddr())},
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outgoing: make(chan *irc.Message, 64),
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ringMessages: make(chan ringMessage),
closed: make(chan struct{}),
ourMessages: make(map[*irc.Message]struct{}),
}
go func() {
if err := dc.writeMessages(); err != nil {
dc.logger.Printf("failed to write message: %v", err)
}
if err := dc.net.Close(); err != nil {
dc.logger.Printf("failed to close connection: %v", err)
} else {
dc.logger.Printf("connection closed")
}
}()
return dc
}
func (dc *downstreamConn) prefix() *irc.Prefix {
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return &irc.Prefix{
Name: dc.nick,
User: dc.username,
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// TODO: fill the host?
}
}
func (dc *downstreamConn) marshalChannel(uc *upstreamConn, name string) string {
return name
}
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func (dc *downstreamConn) forEachNetwork(f func(*network)) {
if dc.network != nil {
f(dc.network)
} else {
dc.user.forEachNetwork(f)
}
}
func (dc *downstreamConn) forEachUpstream(f func(*upstreamConn)) {
dc.user.forEachUpstream(func(uc *upstreamConn) {
if dc.network != nil && uc.network != dc.network {
return
}
f(uc)
})
}
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// upstream returns the upstream connection, if any. If there are zero or if
// there are multiple upstream connections, it returns nil.
func (dc *downstreamConn) upstream() *upstreamConn {
if dc.network == nil {
return nil
}
var upstream *upstreamConn
dc.forEachUpstream(func(uc *upstreamConn) {
upstream = uc
})
return upstream
}
func (dc *downstreamConn) unmarshalChannel(name string) (*upstreamConn, string, error) {
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if uc := dc.upstream(); uc != nil {
return uc, name, nil
}
// TODO: extract network name from channel name if dc.upstream == nil
var channel *upstreamChannel
var err error
dc.forEachUpstream(func(uc *upstreamConn) {
if err != nil {
return
}
if ch, ok := uc.channels[name]; ok {
if channel != nil {
err = fmt.Errorf("ambiguous channel name %q", name)
} else {
channel = ch
}
}
})
if channel == nil {
return nil, "", ircError{&irc.Message{
Command: irc.ERR_NOSUCHCHANNEL,
Params: []string{name, "No such channel"},
}}
}
return channel.conn, channel.Name, nil
}
func (dc *downstreamConn) marshalNick(uc *upstreamConn, nick string) string {
if nick == uc.nick {
return dc.nick
}
return nick
}
func (dc *downstreamConn) marshalUserPrefix(uc *upstreamConn, prefix *irc.Prefix) *irc.Prefix {
if prefix.Name == uc.nick {
return dc.prefix()
}
return prefix
}
func (dc *downstreamConn) isClosed() bool {
select {
case <-dc.closed:
return true
default:
return false
}
}
func (dc *downstreamConn) readMessages(ch chan<- downstreamIncomingMessage) error {
dc.logger.Printf("new connection")
for {
msg, err := dc.irc.ReadMessage()
if err == io.EOF {
break
} else if err != nil {
return fmt.Errorf("failed to read IRC command: %v", err)
}
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if dc.srv.Debug {
dc.logger.Printf("received: %v", msg)
}
ch <- downstreamIncomingMessage{msg, dc}
}
return nil
}
func (dc *downstreamConn) writeMessages() error {
for {
var err error
var closed bool
select {
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case msg := <-dc.outgoing:
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if dc.srv.Debug {
dc.logger.Printf("sent: %v", msg)
}
err = dc.irc.WriteMessage(msg)
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case ringMessage := <-dc.ringMessages:
consumer, uc := ringMessage.consumer, ringMessage.upstreamConn
for {
msg := consumer.Peek()
if msg == nil {
break
}
dc.lock.Lock()
_, ours := dc.ourMessages[msg]
delete(dc.ourMessages, msg)
dc.lock.Unlock()
if ours {
// The message comes from our connection, don't echo it
// back
continue
}
msg = msg.Copy()
switch msg.Command {
case "PRIVMSG":
// TODO: detect whether it's a user or a channel
msg.Params[0] = dc.marshalChannel(uc, msg.Params[0])
default:
panic("expected to consume a PRIVMSG message")
}
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if dc.srv.Debug {
dc.logger.Printf("sent: %v", msg)
}
err = dc.irc.WriteMessage(msg)
if err != nil {
break
}
consumer.Consume()
}
case <-dc.closed:
closed = true
}
if err != nil {
return err
}
if closed {
break
}
}
return nil
}
func (dc *downstreamConn) Close() error {
if dc.isClosed() {
return fmt.Errorf("downstream connection already closed")
}
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if u := dc.user; u != nil {
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u.lock.Lock()
for i := range u.downstreamConns {
if u.downstreamConns[i] == dc {
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u.downstreamConns = append(u.downstreamConns[:i], u.downstreamConns[i+1:]...)
break
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}
}
u.lock.Unlock()
}
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close(dc.closed)
return nil
}
func (dc *downstreamConn) SendMessage(msg *irc.Message) {
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dc.outgoing <- msg
}
func (dc *downstreamConn) handleMessage(msg *irc.Message) error {
switch msg.Command {
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case "QUIT":
return dc.Close()
default:
if dc.registered {
return dc.handleMessageRegistered(msg)
} else {
return dc.handleMessageUnregistered(msg)
}
}
}
func (dc *downstreamConn) handleMessageUnregistered(msg *irc.Message) error {
switch msg.Command {
case "NICK":
if err := parseMessageParams(msg, &dc.nick); err != nil {
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return err
}
case "USER":
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var username string
if err := parseMessageParams(msg, &username, nil, nil, &dc.realname); err != nil {
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return err
}
dc.rawUsername = username
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case "PASS":
if err := parseMessageParams(msg, &dc.password); err != nil {
return err
}
default:
dc.logger.Printf("unhandled message: %v", msg)
return newUnknownCommandError(msg.Command)
}
if dc.rawUsername != "" && dc.nick != "" {
return dc.register()
}
return nil
}
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func sanityCheckServer(addr string) error {
dialer := net.Dialer{Timeout: 30 * time.Second}
conn, err := tls.DialWithDialer(&dialer, "tcp", addr, nil)
if err != nil {
return err
}
return conn.Close()
}
func (dc *downstreamConn) register() error {
username := dc.rawUsername
var networkName string
if i := strings.LastIndexAny(username, "/@"); i >= 0 {
networkName = username[i+1:]
}
if i := strings.IndexAny(username, "/@"); i >= 0 {
username = username[:i]
}
dc.username = "~" + username
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password := dc.password
dc.password = ""
u := dc.srv.getUser(username)
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if u == nil {
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dc.logger.Printf("failed authentication for %q: unknown username", username)
return errAuthFailed
}
err := bcrypt.CompareHashAndPassword([]byte(u.Password), []byte(password))
if err != nil {
dc.logger.Printf("failed authentication for %q: %v", username, err)
return errAuthFailed
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}
var network *network
if networkName != "" {
network = u.getNetwork(networkName)
if network == nil {
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addr := networkName
if !strings.ContainsRune(addr, ':') {
addr = addr + ":6697"
}
dc.logger.Printf("trying to connect to new network %q", addr)
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if err := sanityCheckServer(addr); err != nil {
dc.logger.Printf("failed to connect to %q: %v", addr, err)
return ircError{&irc.Message{
Command: irc.ERR_PASSWDMISMATCH,
Params: []string{"*", fmt.Sprintf("Failed to connect to %q", networkName)},
}}
}
dc.logger.Printf("auto-saving network %q", networkName)
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network, err = u.createNetwork(networkName, dc.nick)
if err != nil {
return err
}
}
}
dc.registered = true
dc.user = u
dc.network = network
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u.lock.Lock()
firstDownstream := len(u.downstreamConns) == 0
u.downstreamConns = append(u.downstreamConns, dc)
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u.lock.Unlock()
dc.SendMessage(&irc.Message{
Prefix: dc.srv.prefix(),
Command: irc.RPL_WELCOME,
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Params: []string{dc.nick, "Welcome to soju, " + dc.nick},
})
dc.SendMessage(&irc.Message{
Prefix: dc.srv.prefix(),
Command: irc.RPL_YOURHOST,
Params: []string{dc.nick, "Your host is " + dc.srv.Hostname},
})
dc.SendMessage(&irc.Message{
Prefix: dc.srv.prefix(),
Command: irc.RPL_CREATED,
Params: []string{dc.nick, "Who cares when the server was created?"},
})
dc.SendMessage(&irc.Message{
Prefix: dc.srv.prefix(),
Command: irc.RPL_MYINFO,
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Params: []string{dc.nick, dc.srv.Hostname, "soju", "aiwroO", "OovaimnqpsrtklbeI"},
})
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// TODO: RPL_ISUPPORT
dc.SendMessage(&irc.Message{
Prefix: dc.srv.prefix(),
Command: irc.ERR_NOMOTD,
Params: []string{dc.nick, "No MOTD"},
})
dc.forEachUpstream(func(uc *upstreamConn) {
for _, ch := range uc.channels {
if ch.complete {
forwardChannel(dc, ch)
}
}
historyName := dc.username
var seqPtr *uint64
if firstDownstream {
seq, ok := uc.history[historyName]
if ok {
seqPtr = &seq
}
}
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consumer, ch := uc.ring.NewConsumer(seqPtr)
go func() {
for {
var closed bool
select {
case <-ch:
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dc.ringMessages <- ringMessage{consumer, uc}
case <-dc.closed:
closed = true
}
if closed {
break
}
}
seq := consumer.Close()
dc.user.lock.Lock()
lastDownstream := len(dc.user.downstreamConns) == 0
dc.user.lock.Unlock()
if lastDownstream {
uc.history[historyName] = seq
}
}()
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})
return nil
}
func (dc *downstreamConn) runUntilRegistered() error {
for !dc.registered {
msg, err := dc.irc.ReadMessage()
if err != nil {
return fmt.Errorf("failed to read IRC command: %v", err)
}
err = dc.handleMessage(msg)
if ircErr, ok := err.(ircError); ok {
ircErr.Message.Prefix = dc.srv.prefix()
dc.SendMessage(ircErr.Message)
} else if err != nil {
return fmt.Errorf("failed to handle IRC command %q: %v", msg, err)
}
}
return nil
}
func (dc *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
switch msg.Command {
case "PING":
dc.SendMessage(&irc.Message{
Prefix: dc.srv.prefix(),
Command: "PONG",
Params: msg.Params,
})
return nil
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case "USER":
return ircError{&irc.Message{
Command: irc.ERR_ALREADYREGISTERED,
Params: []string{dc.nick, "You may not reregister"},
}}
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case "NICK":
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var nick string
if err := parseMessageParams(msg, &nick); err != nil {
return err
}
var err error
dc.forEachNetwork(func(n *network) {
if err != nil {
return
}
n.Nick = nick
err = dc.srv.db.StoreNetwork(dc.user.Username, &n.Network)
})
if err != nil {
return err
}
dc.forEachUpstream(func(uc *upstreamConn) {
uc.SendMessage(msg)
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})
case "JOIN", "PART":
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var name string
if err := parseMessageParams(msg, &name); err != nil {
return err
}
uc, upstreamName, err := dc.unmarshalChannel(name)
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if err != nil {
return ircError{&irc.Message{
Command: irc.ERR_NOSUCHCHANNEL,
Params: []string{name, err.Error()},
}}
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}
uc.SendMessage(&irc.Message{
Command: msg.Command,
Params: []string{upstreamName},
})
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switch msg.Command {
case "JOIN":
err := dc.srv.db.StoreChannel(uc.network.ID, &Channel{
Name: upstreamName,
})
if err != nil {
dc.logger.Printf("failed to create channel %q in DB: %v", upstreamName, err)
}
case "PART":
if err := dc.srv.db.DeleteChannel(uc.network.ID, upstreamName); err != nil {
dc.logger.Printf("failed to delete channel %q in DB: %v", upstreamName, err)
}
}
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case "MODE":
if msg.Prefix == nil {
return fmt.Errorf("missing prefix")
}
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var name string
if err := parseMessageParams(msg, &name); err != nil {
return err
}
var modeStr string
if len(msg.Params) > 1 {
modeStr = msg.Params[1]
}
if msg.Prefix.Name != name {
uc, upstreamName, err := dc.unmarshalChannel(name)
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if err != nil {
return err
}
if modeStr != "" {
uc.SendMessage(&irc.Message{
Command: "MODE",
Params: []string{upstreamName, modeStr},
})
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} else {
ch, ok := uc.channels[upstreamName]
if !ok {
return ircError{&irc.Message{
Command: irc.ERR_NOSUCHCHANNEL,
Params: []string{name, "No such channel"},
}}
}
dc.SendMessage(&irc.Message{
Prefix: dc.srv.prefix(),
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Command: irc.RPL_CHANNELMODEIS,
Params: []string{name, string(ch.modes)},
})
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}
} else {
if name != dc.nick {
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return ircError{&irc.Message{
Command: irc.ERR_USERSDONTMATCH,
Params: []string{dc.nick, "Cannot change mode for other users"},
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}}
}
if modeStr != "" {
dc.forEachUpstream(func(uc *upstreamConn) {
uc.SendMessage(&irc.Message{
Command: "MODE",
Params: []string{uc.nick, modeStr},
})
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})
} else {
dc.SendMessage(&irc.Message{
Prefix: dc.srv.prefix(),
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Command: irc.RPL_UMODEIS,
Params: []string{""}, // TODO
})
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}
}
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case "PRIVMSG":
var targetsStr, text string
if err := parseMessageParams(msg, &targetsStr, &text); err != nil {
return err
}
for _, name := range strings.Split(targetsStr, ",") {
uc, upstreamName, err := dc.unmarshalChannel(name)
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if err != nil {
return err
}
if upstreamName == "NickServ" {
dc.handleNickServPRIVMSG(uc, text)
}
uc.SendMessage(&irc.Message{
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Command: "PRIVMSG",
Params: []string{upstreamName, text},
})
dc.lock.Lock()
dc.ourMessages[msg] = struct{}{}
dc.lock.Unlock()
uc.ring.Produce(msg)
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}
default:
dc.logger.Printf("unhandled message: %v", msg)
return newUnknownCommandError(msg.Command)
}
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return nil
}
func (dc *downstreamConn) handleNickServPRIVMSG(uc *upstreamConn, text string) {
username, password, ok := parseNickServCredentials(text, uc.nick)
if !ok {
return
}
dc.logger.Printf("auto-saving NickServ credentials with username %q", username)
n := uc.network
n.SASL.Mechanism = "PLAIN"
n.SASL.Plain.Username = username
n.SASL.Plain.Password = password
if err := dc.srv.db.StoreNetwork(dc.user.Username, &n.Network); err != nil {
dc.logger.Printf("failed to save NickServ credentials: %v", err)
}
}
func parseNickServCredentials(text, nick string) (username, password string, ok bool) {
fields := strings.Fields(text)
if len(fields) < 2 {
return "", "", false
}
cmd := strings.ToUpper(fields[0])
params := fields[1:]
switch cmd {
case "REGISTER":
username = nick
password = params[0]
case "IDENTIFY":
if len(params) == 1 {
username = nick
} else {
username = params[0]
}
password = params[1]
}
return username, password, true
}