source: code/trunk/downstream.go@ 41

package jounce

import (
        "fmt"
        "io"
        "net"
        "strings"

        "gopkg.in/irc.v3"
)

type ircError struct {
        Message *irc.Message
}

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",
                },
        }}
}

func (err ircError) Error() string {
        return err.Message.String()
}

type downstreamConn struct {
        net      net.Conn
        irc      *irc.Conn
        srv      *Server
        logger   Logger
        messages chan<- *irc.Message

        registered bool
        user       *user
        closed     bool
        nick       string
        username   string
        realname   string
}

func newDownstreamConn(srv *Server, netConn net.Conn) *downstreamConn {
        msgs := make(chan *irc.Message, 64)
        conn := &downstreamConn{
                net:      netConn,
                irc:      irc.NewConn(netConn),
                srv:      srv,
                logger:   &prefixLogger{srv.Logger, fmt.Sprintf("downstream %q: ", netConn.RemoteAddr())},
                messages: msgs,
        }

        go func() {
                for msg := range msgs {
                        if err := conn.irc.WriteMessage(msg); err != nil {
                                conn.logger.Printf("failed to write message: %v", err)
                        }
                }
        }()

        return conn
}

func (c *downstreamConn) prefix() *irc.Prefix {
        return &irc.Prefix{
                Name: c.nick,
                User: c.username,
                // TODO: fill the host?
        }
}

func (c *downstreamConn) readMessages() error {
        c.logger.Printf("new connection")
        defer c.Close()

        for {
                msg, err := c.irc.ReadMessage()
                if err == io.EOF {
                        break
                } else if err != nil {
                        return fmt.Errorf("failed to read IRC command: %v", err)
                }

                err = c.handleMessage(msg)
                if ircErr, ok := err.(ircError); ok {
                        ircErr.Message.Prefix = c.srv.prefix()
                        c.messages <- ircErr.Message
                } else if err != nil {
                        return fmt.Errorf("failed to handle IRC command %q: %v", msg.Command, err)
                }

                if c.closed {
                        return nil
                }
        }

        return c.Close()
}

func (c *downstreamConn) Close() error {
        if c.closed {
                return fmt.Errorf("downstream connection already closed")
        }

        if u := c.user; u != nil {
                u.lock.Lock()
                for i := range u.downstreamConns {
                        if u.downstreamConns[i] == c {
                                u.downstreamConns = append(u.downstreamConns[:i], u.downstreamConns[i+1:]...)
                        }
                }
                u.lock.Unlock()
        }

        close(c.messages)
        c.closed = true

        return c.net.Close()
}

func (c *downstreamConn) handleMessage(msg *irc.Message) error {
        switch msg.Command {
        case "QUIT":
                return c.Close()
        case "PING":
                // TODO: handle params
                c.messages <- &irc.Message{
                        Prefix:  c.srv.prefix(),
                        Command: "PONG",
                        Params:  []string{c.srv.Hostname},
                }
                return nil
        default:
                if c.registered {
                        return c.handleMessageRegistered(msg)
                } else {
                        return c.handleMessageUnregistered(msg)
                }
        }
}

func (c *downstreamConn) handleMessageUnregistered(msg *irc.Message) error {
        switch msg.Command {
        case "NICK":
                if len(msg.Params) != 1 {
                        return newNeedMoreParamsError(msg.Command)
                }
                c.nick = msg.Params[0]
        case "USER":
                if len(msg.Params) != 4 {
                        return newNeedMoreParamsError(msg.Command)
                }
                c.username = "~" + msg.Params[0]
                c.realname = msg.Params[3]
        default:
                c.logger.Printf("unhandled message: %v", msg)
                return newUnknownCommandError(msg.Command)
        }
        if c.username != "" && c.nick != "" {
                return c.register()
        }
        return nil
}

func (c *downstreamConn) register() error {
        u := c.srv.getUser(strings.TrimPrefix(c.username, "~"))
        if u == nil {
                c.logger.Printf("failed authentication: unknown username %q", c.username)
                c.messages <- &irc.Message{
                        Prefix:  c.srv.prefix(),
                        Command: irc.ERR_PASSWDMISMATCH,
                        Params:  []string{"*", "Invalid username or password"},
                }
                return nil
        }

        c.registered = true
        c.user = u

        u.lock.Lock()
        u.downstreamConns = append(u.downstreamConns, c)
        u.lock.Unlock()

        c.messages <- &irc.Message{
                Prefix:  c.srv.prefix(),
                Command: irc.RPL_WELCOME,
                Params:  []string{c.nick, "Welcome to jounce, " + c.nick},
        }
        c.messages <- &irc.Message{
                Prefix:  c.srv.prefix(),
                Command: irc.RPL_YOURHOST,
                Params:  []string{c.nick, "Your host is " + c.srv.Hostname},
        }
        c.messages <- &irc.Message{
                Prefix:  c.srv.prefix(),
                Command: irc.RPL_CREATED,
                Params:  []string{c.nick, "This server was created <datetime>"}, // TODO
        }
        c.messages <- &irc.Message{
                Prefix:  c.srv.prefix(),
                Command: irc.RPL_MYINFO,
                Params:  []string{c.nick, c.srv.Hostname, "jounce", "aiwroO", "OovaimnqpsrtklbeI"},
        }
        c.messages <- &irc.Message{
                Prefix:  c.srv.prefix(),
                Command: irc.ERR_NOMOTD,
                Params:  []string{c.nick, "No MOTD"},
        }

        u.forEachUpstream(func(uc *upstreamConn) {
                // TODO: fix races accessing upstream connection data
                for _, ch := range uc.channels {
                        if ch.complete {
                                forwardChannel(c, ch)
                        }
                }
        })
        return nil
}

func (c *downstreamConn) handleMessageRegistered(msg *irc.Message) error {
        switch msg.Command {
        case "NICK", "USER":
                return ircError{&irc.Message{
                        Command: irc.ERR_ALREADYREGISTERED,
                        Params: []string{
                                c.nick,
                                "You may not reregister",
                        },
                }}
        default:
                c.logger.Printf("unhandled message: %v", msg)
                return newUnknownCommandError(msg.Command)
        }
}