src/modules/m_repeat.cpp

   1 /*
   2  * InspIRCd -- Internet Relay Chat Daemon
   3  *
   4  *   Copyright (C) 2013 Daniel Vassdal <shutter@canternet.org>
   5  *
   6  * This file is part of InspIRCd.  InspIRCd is free software: you can
   7  * redistribute it and/or modify it under the terms of the GNU General Public
   8  * License as published by the Free Software Foundation, version 2.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  12  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  13  * details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19
  20 #include "inspircd.h"
  21
  22 #ifdef _WIN32
  23 // windows.h defines this
  24 #undef min
  25 #endif
  26
  27 class RepeatMode : public ModeHandler
  28 {
  29  private:
  30         struct RepeatItem
  31         {
  32                 time_t ts;
  33                 std::string line;
  34                 RepeatItem(time_t TS, const std::string& Line) : ts(TS), line(Line) { }
  35         };
  36
  37         typedef std::deque<RepeatItem> RepeatItemList;
  38
  39         struct MemberInfo
  40         {
  41                 RepeatItemList ItemList;
  42                 unsigned int Counter;
  43                 MemberInfo() : Counter(0) {}
  44         };
  45
  46         struct ModuleSettings
  47         {
  48                 unsigned int MaxLines;
  49                 unsigned int MaxSecs;
  50                 unsigned int MaxBacklog;
  51                 unsigned int MaxDiff;
  52                 ModuleSettings() : MaxLines(0), MaxSecs(0), MaxBacklog(0), MaxDiff() { }
  53         };
  54
  55         std::vector<std::vector<unsigned int> > mx;
  56         ModuleSettings ms;
  57
  58         bool CompareLines(const std::string& message, const std::string& historyline, unsigned int trigger)
  59         {
  60                 if (trigger)
  61                         return (Levenshtein(message, historyline) <= trigger);
  62                 else
  63                         return (message == historyline);
  64         }
  65
  66         unsigned int Levenshtein(const std::string& s1, const std::string& s2)
  67         {
  68                 unsigned int l1 = s1.size();
  69                 unsigned int l2 = s2.size();
  70
  71                 for (unsigned int i = 0; i <= l1; i++)
  72                         mx[i][0] = i;
  73                 for (unsigned int i = 0; i <= l2; i++)
  74                         mx[0][i] = i;
  75                 for (unsigned int i = 1; i <= l1; i++)
  76                         for (unsigned int j = 1; j <= l2; j++)
  77                                 mx[i][j] = std::min(std::min(mx[i - 1][j] + 1, mx[i][j - 1] + 1), mx[i - 1][j - 1] + (s1[i - 1] == s2[j - 1] ? 0 : 1));
  78                 return (mx[l1][l2]);
  79         }
  80
  81  public:
  82         enum RepeatAction
  83         {
  84                 ACT_KICK,
  85                 ACT_BLOCK,
  86                 ACT_BAN
  87         };
  88
  89         class ChannelSettings
  90         {
  91          public:
  92                 RepeatAction Action;
  93                 unsigned int Backlog;
  94                 unsigned int Lines;
  95                 unsigned int Diff;
  96                 unsigned int Seconds;
  97
  98                 std::string serialize()
  99                 {
 100                         std::string ret = ((Action == ACT_BAN) ? "*" : (Action == ACT_BLOCK ? "~" : "")) + ConvToStr(Lines) + ":" + ConvToStr(Seconds);
 101                         if (Diff)
 102                         {
 103                                 ret += ":" + ConvToStr(Diff);
 104                                 if (Backlog)
 105                                         ret += ":" + ConvToStr(Backlog);
 106                         }
 107                         return ret;
 108                 }
 109         };
 110
 111         SimpleExtItem<MemberInfo> MemberInfoExt;
 112         SimpleExtItem<ChannelSettings> ChanSet;
 113
 114         RepeatMode(Module* Creator)
 115                 : ModeHandler(Creator, "repeat", 'E', PARAM_SETONLY, MODETYPE_CHANNEL)
 116                 , MemberInfoExt("repeat_memb", Creator)
 117                 , ChanSet("repeat", Creator)
 118         {
 119         }
 120
 121         ModeAction OnModeChange(User* source, User* dest, Channel* channel, std::string& parameter, bool adding)
 122         {
 123                 if (!adding)
 124                 {
 125                         if (!channel->IsModeSet(this))
 126                                 return MODEACTION_DENY;
 127
 128                         // Unset the per-membership extension when the mode is removed
 129                         const UserMembList* users = channel->GetUsers();
 130                         for (UserMembCIter i = users->begin(); i != users->end(); ++i)
 131                                 MemberInfoExt.unset(i->second);
 132
 133                         ChanSet.unset(channel);
 134                         return MODEACTION_ALLOW;
 135                 }
 136
 137                 if (channel->GetModeParameter(this) == parameter)
 138                         return MODEACTION_DENY;
 139
 140                 ChannelSettings settings;
 141                 if (!ParseSettings(source, parameter, settings))
 142                 {
 143                         source->WriteNotice("*** Invalid syntax. Syntax is {[~*]}[lines]:[time]{:[difference]}{:[backlog]}");
 144                         return MODEACTION_DENY;
 145                 }
 146
 147                 if ((settings.Backlog > 0) && (settings.Lines > settings.Backlog))
 148                 {
 149                         source->WriteNotice("*** You can't set needed lines higher than backlog");
 150                         return MODEACTION_DENY;
 151                 }
 152
 153                 LocalUser* localsource = IS_LOCAL(source);
 154                 if ((localsource) && (!ValidateSettings(localsource, settings)))
 155                         return MODEACTION_DENY;
 156
 157                 ChanSet.set(channel, settings);
 158
 159                 return MODEACTION_ALLOW;
 160         }
 161
 162         bool MatchLine(Membership* memb, ChannelSettings* rs, std::string message)
 163         {
 164                 // If the message is larger than whatever size it's set to,
 165                 // let's pretend it isn't. If the first 512 (def. setting) match, it's probably spam.
 166                 if (message.size() > mx.size())
 167                         message.erase(mx.size());
 168
 169                 MemberInfo* rp = MemberInfoExt.get(memb);
 170                 if (!rp)
 171                 {
 172                         rp = new MemberInfo;
 173                         MemberInfoExt.set(memb, rp);
 174                 }
 175
 176                 unsigned int matches = 0;
 177                 if (!rs->Backlog)
 178                         matches = rp->Counter;
 179
 180                 RepeatItemList& items = rp->ItemList;
 181                 const unsigned int trigger = (message.size() * rs->Diff / 100);
 182                 const time_t now = ServerInstance->Time();
 183
 184                 std::transform(message.begin(), message.end(), message.begin(), ::tolower);
 185
 186                 for (std::deque<RepeatItem>::iterator it = items.begin(); it != items.end(); ++it)
 187                 {
 188                         if (it->ts < now)
 189                         {
 190                                 items.erase(it, items.end());
 191                                 matches = 0;
 192                                 break;
 193                         }
 194
 195                         if (CompareLines(message, it->line, trigger))
 196                         {
 197                                 if (++matches >= rs->Lines)
 198                                 {
 199                                         if (rs->Action != ACT_BLOCK)
 200                                                 rp->Counter = 0;
 201                                         return true;
 202                                 }
 203                         }
 204                         else if ((ms.MaxBacklog == 0) || (rs->Backlog == 0))
 205                         {
 206                                 matches = 0;
 207                                 items.clear();
 208                                 break;
 209                         }
 210                 }
 211
 212                 unsigned int max_items = (rs->Backlog ? rs->Backlog : 1);
 213                 if (items.size() >= max_items)
 214                         items.pop_back();
 215
 216                 items.push_front(RepeatItem(now + rs->Seconds, message));
 217                 rp->Counter = matches;
 218                 return false;
 219         }
 220
 221         void Resize(size_t size)
 222         {
 223                 if (size == mx.size())
 224                         return;
 225                 mx.resize(size);
 226
 227                 if (mx.size() > size)
 228                 {
 229                         mx.resize(size);
 230                         for (unsigned int i = 0; i < mx.size(); i++)
 231                                 mx[i].resize(size);
 232                 }
 233                 else
 234                 {
 235                         for (unsigned int i = 0; i < mx.size(); i++)
 236                         {
 237                                 mx[i].resize(size);
 238                                 std::vector<unsigned int>(mx[i]).swap(mx[i]);
 239                         }
 240                         std::vector<std::vector<unsigned int> >(mx).swap(mx);
 241                 }
 242         }
 243
 244         void ReadConfig()
 245         {
 246                 ConfigTag* conf = ServerInstance->Config->ConfValue("repeat");
 247                 ms.MaxLines = conf->getInt("maxlines", 20);
 248                 ms.MaxBacklog = conf->getInt("maxbacklog", 20);
 249                 ms.MaxSecs = conf->getInt("maxsecs", 0);
 250
 251                 ms.MaxDiff = conf->getInt("maxdistance", 50);
 252                 if (ms.MaxDiff > 100)
 253                         ms.MaxDiff = 100;
 254
 255                 unsigned int newsize = conf->getInt("size", 512);
 256                 if (newsize > ServerInstance->Config->Limits.MaxLine)
 257                         newsize = ServerInstance->Config->Limits.MaxLine;
 258                 Resize(newsize);
 259         }
 260
 261         std::string GetModuleSettings() const
 262         {
 263                 return ConvToStr(ms.MaxLines) + ":" + ConvToStr(ms.MaxSecs) + ":" + ConvToStr(ms.MaxDiff) + ":" + ConvToStr(ms.MaxBacklog);
 264         }
 265
 266  private:
 267         bool ParseSettings(User* source, std::string& parameter, ChannelSettings& settings)
 268         {
 269                 irc::sepstream stream(parameter, ':');
 270                 std::string     item;
 271                 if (!stream.GetToken(item))
 272                         // Required parameter missing
 273                         return false;
 274
 275                 if ((item[0] == '*') || (item[0] == '~'))
 276                 {
 277                         settings.Action = ((item[0] == '*') ? ACT_BAN : ACT_BLOCK);
 278                         item.erase(item.begin());
 279                 }
 280                 else
 281                         settings.Action = ACT_KICK;
 282
 283                 if ((settings.Lines = ConvToInt(item)) == 0)
 284                         return false;
 285
 286                 if ((!stream.GetToken(item)) || ((settings.Seconds = InspIRCd::Duration(item)) == 0))
 287                         // Required parameter missing
 288                         return false;
 289
 290                 // The diff and backlog parameters are optional
 291                 settings.Diff = settings.Backlog = 0;
 292                 if (stream.GetToken(item))
 293                 {
 294                         // There is a diff parameter, see if it's valid (> 0)
 295                         if ((settings.Diff = ConvToInt(item)) == 0)
 296                                 return false;
 297
 298                         if (stream.GetToken(item))
 299                         {
 300                                 // There is a backlog parameter, see if it's valid
 301                                 if ((settings.Backlog = ConvToInt(item)) == 0)
 302                                         return false;
 303
 304                                 // If there are still tokens, then it's invalid because we allow only 4
 305                                 if (stream.GetToken(item))
 306                                         return false;
 307                         }
 308                 }
 309
 310                 parameter = settings.serialize();
 311                 return true;
 312         }
 313
 314         bool ValidateSettings(LocalUser* source, const ChannelSettings& settings)
 315         {
 316                 if (settings.Backlog && !ms.MaxBacklog)
 317                 {
 318                         source->WriteNotice("*** The server administrator has disabled backlog matching");
 319                         return false;
 320                 }
 321
 322                 if (settings.Diff)
 323                 {
 324                         if (settings.Diff > ms.MaxDiff)
 325                         {
 326                                 if (ms.MaxDiff == 0)
 327                                         source->WriteNotice("*** The server administrator has disabled matching on edit distance");
 328                                 else
 329                                         source->WriteNotice("*** The distance you specified is too great. Maximum allowed is " + ConvToStr(ms.MaxDiff));
 330                                 return false;
 331                         }
 332
 333                         if (ms.MaxLines && settings.Lines > ms.MaxLines)
 334                         {
 335                                 source->WriteNotice("*** The line number you specified is too great. Maximum allowed is " + ConvToStr(ms.MaxLines));
 336                                 return false;
 337                         }
 338
 339                         if (ms.MaxSecs && settings.Seconds > ms.MaxSecs)
 340                         {
 341                                 source->WriteNotice("*** The seconds you specified is too great. Maximum allowed is " + ConvToStr(ms.MaxSecs));
 342                                 return false;
 343                         }
 344                 }
 345
 346                 return true;
 347         }
 348 };
 349
 350 class RepeatModule : public Module
 351 {
 352         RepeatMode rm;
 353
 354  public:
 355         RepeatModule() : rm(this) {}
 356
 357         void init() CXX11_OVERRIDE
 358         {
 359                 ServerInstance->Modules->AddService(rm);
 360                 ServerInstance->Modules->AddService(rm.ChanSet);
 361                 ServerInstance->Modules->AddService(rm.MemberInfoExt);
 362                 Implementation eventlist[] = { I_OnUserPreMessage, I_OnRehash };
 363                 ServerInstance->Modules->Attach(eventlist, this, sizeof(eventlist)/sizeof(Implementation));
 364                 rm.ReadConfig();
 365         }
 366
 367         void OnRehash(User* user) CXX11_OVERRIDE
 368         {
 369                 rm.ReadConfig();
 370         }
 371
 372         ModResult OnUserPreMessage(User* user, void* dest, int target_type, std::string& text, char status, CUList& exempt_list, MessageType msgtype) CXX11_OVERRIDE
 373         {
 374                 if (target_type != TYPE_CHANNEL || !IS_LOCAL(user))
 375                         return MOD_RES_PASSTHRU;
 376
 377                 Membership* memb = ((Channel*)dest)->GetUser(user);
 378                 if (!memb || !memb->chan->IsModeSet(&rm))
 379                         return MOD_RES_PASSTHRU;
 380
 381                 if (ServerInstance->OnCheckExemption(user, memb->chan, "repeat") == MOD_RES_ALLOW)
 382                         return MOD_RES_PASSTHRU;
 383
 384                 RepeatMode::ChannelSettings* settings = rm.ChanSet.get(memb->chan);
 385                 if (!settings)
 386                         return MOD_RES_PASSTHRU;
 387
 388                 if (rm.MatchLine(memb, settings, text))
 389                 {
 390                         if (settings->Action == RepeatMode::ACT_BLOCK)
 391                         {
 392                                 user->WriteNotice("*** This line is too similiar to one of your last lines.");
 393                                 return MOD_RES_DENY;
 394                         }
 395
 396                         if (settings->Action == RepeatMode::ACT_BAN)
 397                         {
 398                                 std::vector<std::string> parameters;
 399                                 parameters.push_back(memb->chan->name);
 400                                 parameters.push_back("+b");
 401                                 parameters.push_back("*!*@" + user->dhost);
 402                                 ServerInstance->Modes->Process(parameters, ServerInstance->FakeClient);
 403                         }
 404
 405                         memb->chan->KickUser(ServerInstance->FakeClient, user, "Repeat flood");
 406                         return MOD_RES_DENY;
 407                 }
 408                 return MOD_RES_PASSTHRU;
 409         }
 410
 411         void Prioritize() CXX11_OVERRIDE
 412         {
 413                 ServerInstance->Modules->SetPriority(this, I_OnUserPreMessage, PRIORITY_LAST);
 414         }
 415
 416         Version GetVersion() CXX11_OVERRIDE
 417         {
 418                 return Version("Provides the +E channel mode - for blocking of similiar messages", VF_COMMON|VF_VENDOR, rm.GetModuleSettings());
 419         }
 420 };
 421
 422 MODULE_INIT(RepeatModule)