Initial commit of utilities

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

cmd/ircmirror/ircwriters.go

@@ -0,0 +1,177 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright (C) 2021 Jason A. Donenfeld. All Rights Reserved.
+ */
+
+package main
+
+import (
+	"bufio"
+	"container/list"
+	"log"
+	"math/rand"
+	"net"
+	"os"
+	"regexp"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"golang.zx2c4.com/irc/hbot"
+)
+
+var words []string
+
+func init() {
+	f, err := os.Open("/usr/share/dict/words")
+	if err != nil {
+		log.Fatalf("Unable to open dictionary: %v", err)
+	}
+	defer f.Close()
+	scanner := bufio.NewScanner(f)
+	matcher := regexp.MustCompile(`^[a-zA-Z0-9_-]{3,}$`)
+	for scanner.Scan() {
+		word := scanner.Text()
+		if !matcher.MatchString(word) {
+			continue
+		}
+		words = append(words, word)
+	}
+	if len(words) == 0 {
+		log.Fatalln("Did not find any words in dictionary")
+	}
+}
+
+func randomNick() string {
+	return words[rand.Intn(len(words))] + words[rand.Intn(len(words))] + strconv.Itoa(rand.Intn(10000))
+}
+
+type ircWriter struct {
+	mu         sync.Mutex
+	bot        *hbot.Bot
+	nick       string
+	mungedNick string
+	usageElem  *list.Element
+	name       string
+}
+
+type ircWriters struct {
+	mu      sync.Mutex
+	byNick  map[string]*ircWriter
+	byUsage list.List
+	server  string
+	channel string
+}
+
+func (writers *ircWriters) runWriter(name string, dialer func(network, address string) (net.Conn, error)) {
+	writer := &ircWriter{name: name}
+	startNick := randomNick()
+	logf := func(format string, args ...interface{}) {
+		log.Printf("[DST %s] "+format, append([]interface{}{name}, args...)...)
+	}
+	writer.bot = hbot.NewBot(&hbot.Config{
+		Host:     writers.server,
+		Nick:     startNick,
+		User:     hbot.CommonBotUserPrefix + startNick,
+		Channels: []string{writers.channel},
+		Dial:     dialer,
+		Logger:   hbot.Logger{Verbosef: logf, Errorf: logf},
+	})
+	go func() {
+		<-writer.bot.Joined()
+		writers.mu.Lock()
+		defer writers.mu.Unlock()
+		writer.mu.Lock()
+		defer writer.mu.Unlock()
+		writer.usageElem = writers.byUsage.PushBack(writer)
+	}()
+	writer.bot.AddTrigger(hbot.Trigger{
+		Condition: func(bot *hbot.Bot, m *hbot.Message) bool {
+			return (m.Command == "436" || m.Command == "433") && len(writer.nick) > 0
+		},
+		Action: func(bot *hbot.Bot, m *hbot.Message) {
+			logf("Failed with nick %q, trying %q\n", writer.mungedNick, writer.mungedNick+"_")
+			writer.mungedNick += "_"
+			if len(writer.mungedNick) > 16 {
+				usidx := strings.IndexByte(writer.mungedNick, '_')
+				uslen := len(writer.mungedNick[usidx:])
+				if uslen >= 16 {
+					writer.mungedNick = writer.nick + "-"
+					if len(writer.mungedNick) > 16 {
+						writer.mungedNick = writer.nick[:15] + "-"
+					}
+				} else {
+					writer.mungedNick = writer.mungedNick[:16-uslen] + writer.mungedNick[usidx:]
+				}
+			}
+			bot.SetNick(writer.mungedNick)
+		},
+	})
+	writer.bot.Run()
+	writers.mu.Lock()
+	writer.mu.Lock()
+	if writer.usageElem != nil {
+		writers.byUsage.Remove(writer.usageElem)
+		delete(writers.byNick, writer.nick)
+	}
+	writer.mu.Unlock()
+	writers.mu.Unlock()
+}
+
+func (writers *ircWriters) getWriter(nick string) *ircWriter {
+	writers.mu.Lock()
+	if writer, ok := writers.byNick[nick]; ok {
+		writer.mu.Lock()
+		if writer.nick == nick {
+			writers.byUsage.MoveToFront(writer.usageElem)
+			writers.mu.Unlock()
+			if writer.bot.Nick() != writer.mungedNick {
+				log.Printf("[DST %s] Changing nick to %q\n", writer.name, nick)
+				writer.bot.SetNick(writer.mungedNick)
+			}
+			return writer
+		}
+		writer.mu.Unlock()
+	}
+	if writers.byUsage.Len() == 0 {
+		writers.mu.Unlock()
+		return nil
+	}
+	writer := writers.byUsage.Back().Value.(*ircWriter)
+	writer.mu.Lock()
+	delete(writers.byNick, writer.nick)
+	writer.nick = nick
+	writer.mungedNick = nick + "-"
+	if len(writer.mungedNick) > 16 {
+		writer.mungedNick = nick[:15] + "-"
+	}
+	writers.byNick[nick] = writer
+	writers.byUsage.MoveToFront(writer.usageElem)
+	writers.mu.Unlock()
+	log.Printf("[DST %s] Changing nick to %q\n", writer.name, nick)
+	writer.bot.SetNick(writer.mungedNick)
+	return writer
+}
+
+func (writers *ircWriters) queueMessage(from, message string) {
+	writer := writers.getWriter(from)
+	if writer == nil {
+		time.AfterFunc(time.Second*3, func() {
+			writers.queueMessage(from, message)
+		})
+		return
+	}
+	log.Printf("[DST %s] Queueing message from %q\n", writer.name, from)
+	writer.bot.Msg(writers.channel, message)
+	writer.mu.Unlock()
+}
+
+func newIrcWriterGroup(server, channel string) *ircWriters {
+	return &ircWriters{
+		mu:      sync.Mutex{},
+		byNick:  make(map[string]*ircWriter, 400),
+		server:  server,
+		channel: channel,
+	}
+}