source: roaraudio/plugins/roard/protocol-irc.c @ 5424:535acd76cf85

//irc.c:

/*
 *      Copyright (C) Philipp 'ph3-der-loewe' Schafft - 2011-2012
 *
 *  This file is part of roard a part of RoarAudio,
 *  a cross-platform sound system for both, home and professional use.
 *  See README for details.
 *
 *  This file is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 3
 *  as published by the Free Software Foundation.
 *
 *  RoarAudio is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this software; see the file COPYING.  If not, write to
 *  the Free Software Foundation, 51 Franklin Street, Fifth Floor,
 *  Boston, MA 02110-1301, USA.
 *
 */

#include <roard/include/roard.h>
#include <ctype.h>

#define MAX_CHANNELS 8

static int on_nick(int client, const char * cmd, char * args, char * text);
static int on_user(int client, const char * cmd, char * args, char * text);
static int on_quit(int client, const char * cmd, char * args, char * text);
static int on_ping(int client, const char * cmd, char * args, char * text);
static int on_lusers(int client, const char * cmd, char * args, char * text);
static int on_whois(int client, const char * cmd, char * args, char * text);
static int on_privmsg(int client, const char * cmd, char * args, char * text);

static int on_list(int client, const char * cmd, char * args, char * text);
static int on_join(int client, const char * cmd, char * args, char * text);
static int on_part(int client, const char * cmd, char * args, char * text);
static int on_names(int client, const char * cmd, char * args, char * text);

static int on_topic(int client, const char * cmd, char * args, char * text);

static int do_join(int client, const char * channel);
static int do_part(int client, const char * channel);
static int do_names(int client, const char * channel);

static void cb_client_delete(struct roar_notify_core * core, struct roar_event * event, void * userdata);

static struct roar_subscriber * subscription_client_delete = NULL;

static char * server_name     = "irc.roard";
static char * server_fullname = "RoarAudio roard IRC Server plugin";

static char * quit_msg = NULL;

static struct channel {
 char * name;
 struct {
  char * text;
  char * user;
  time_t ts;
 } topic;
 size_t client_count;
 int clients[ROAR_CLIENTS_MAX];
} g_channels[MAX_CHANNELS];

static struct command {
 const char * name;
 int (*func)(int client, const char * cmd, char * args, char * text);
} g_commands[] = {
 {"NICK", on_nick},
 {"USER", on_user},
 {"QUIT", on_quit},
 {"PING", on_ping},
 {"LUSERS", on_lusers},
 {"WHOIS", on_whois},
 {"PRIVMSG", on_privmsg},
 {"NOTICE", on_privmsg},
 {"LIST", on_list},
 {"JOIN", on_join},
 {"PART", on_part},
 {"NAMES", on_names},
 {"TOPIC", on_topic},
 {NULL, NULL}
};

static void init(void) {
 struct roar_event event;

 memset(&event, 0, sizeof(event));

 event.event = ROAR_OE_BASICS_DELETE;

 event.emitter = -1;
 event.target = -1;
 event.target_type = ROAR_OT_CLIENT;

 memset(g_channels, 0, sizeof(g_channels));

 subscription_client_delete = roar_notify_core_subscribe(NULL, &event, cb_client_delete, NULL);
}

static int is_valid_name (const char * name) {
 register char c;

 for (; (c = *name) != 0; name++) {
  if ( !(isalnum(c) || c == '-' || c == '_') )
   return 0;
 }

 return 1;
}

static void strip_nl(char * str) {
 register char c;

 for (; (c = *str) != 0; str++) {
  if ( c == '\r' || c == '\n' ) {
   *str = 0;
   return;
  }
 }
}

static char * get_nick(int client) {
 struct roar_client * c;
 clients_get(client, &c);
 return c->name;
}

static const char * get_ident(int client) {
 static char buf[80];
 struct roar_client * c;
 clients_get(client, &c);

 if ( c->uid == -1 ) {
  buf[0] = '~';
  buf[1] = 0;
 } else {
  snprintf(buf, sizeof(buf)-1, "uid%i~", c->uid);
  buf[sizeof(buf)-1] = 0;
 }

 return buf;
}

static const char * get_node(int client) {
 struct roar_client * c;
 static char buf_nnode[80];
 char * nnode;

 clients_get(client, &c);

 roar_nnode_to_str(&(c->nnode), buf_nnode, sizeof(buf_nnode));

 nnode  = strstr(buf_nnode, ": ");
 if ( nnode == NULL ) {
  nnode  = "unknown~";
 } else {
  nnode += 2;
 }

 return nnode;
}

static const char * get_ufull(int client) {
 struct roar_client * c;
 static char buf[80];
 const char * ident = get_ident(client);
 const char * nnode = get_node(client);

 clients_get(client, &c);

 snprintf(buf, sizeof(buf)-1, "%s!%s@%s", c->name, ident, nnode);

 buf[sizeof(buf)-1] = 0;

 return buf;
}

static const char * get_realname(int client) {
 (void)client;
 return "(no realname)";
}

static int get_client_by_nick(const char * nick) {
 struct roar_client * c;
 int i;

 for (i = 0; i < ROAR_CLIENTS_MAX; i++) {
  if ( clients_get(i, &c) != 0 )
   continue;

  if ( !!strcasecmp(c->name, nick) )
   continue;

  return i;
 }

 return -1;
}

static struct channel * get_channel(const char * name) {
 struct channel * c;
 size_t i;

 for (i = 0; i < MAX_CHANNELS; i++) {
  c = &(g_channels[i]);

  if ( !c->client_count )
   continue;

  if ( !!strcasecmp(c->name, name) )
   continue;

  return c;
 }

 return NULL;
}

static size_t get_listener_list(int client, const char * channel, int ** listener) {
 struct channel * c;
 static int clients[ROAR_CLIENTS_MAX];
 size_t ret = 0;
 size_t i, k;
 int j;
 int found;

 for (i = 0; i < MAX_CHANNELS; i++) {
  c = &(g_channels[i]);

  if ( !c->client_count )
   continue;

  if ( c->clients[client] < 1 )
   continue;

  if ( channel != NULL && !!strcasecmp(c->name, channel) )
   continue;

  for (j = 0; j < ROAR_CLIENTS_MAX; j++) {
   if ( c->clients[j] > 0 ) {
    found = 0;
    for (k = 0; k < ret; k++) {
     if ( clients[k] == j ) {
      found = 1;
     }
    }
    if ( !found ) {
     clients[ret] = j;
     ret++;
    }
   }
  }
 }

 *listener = clients;

 return ret;
}

static void put_printf(int client, const char *format, ...) {
 va_list ap;
 struct roar_buffer * buf;
 size_t len = 2048;
 void * data;
 int ret;

 if ( roar_buffer_new_data(&buf, len, &data) == -1 )
  return;

 va_start(ap, format);
 ret = vsnprintf(data, len-1, format, ap);
 va_end(ap);

 if ( roar_buffer_set_len(buf, strlen(data)) == -1 ) {
  roar_buffer_free(buf);
  return;
 }

 clients_add_output(client, &buf);
}

static int do_join(int client, const char * channel) {
 struct channel * c = NULL;
 size_t i;

 if ( channel[0] != '#' )
  return -1;

 if ( !is_valid_name(channel+1) )
  return -1;

 for (i = 0; i < MAX_CHANNELS; i++) {
  if ( !g_channels[i].client_count )
   continue;

  if ( !!strcasecmp(g_channels[i].name, channel) )
   continue;

  c = &(g_channels[i]);
  break;
 }

 if ( c == NULL ) {
  for (i = 0; i < MAX_CHANNELS; i++) {
   if ( g_channels[i].client_count )
    continue;

   c = &(g_channels[i]);
   break;
  }

  if ( c == NULL )
   return -1;

  memset(c, 0, sizeof(*c));

  c->name = roar_mm_strdup(channel);
 }

 if ( c->clients[client] )
  return -1;

 c->clients[client] = 1;
 c->client_count++;

 return 0;
}

static int do_part(int client, const char * channel) {
 struct channel * c = NULL;
 size_t i;

 for (i = 0; i < MAX_CHANNELS; i++) {
  if ( !g_channels[i].client_count )
   continue;

  if ( !!strcasecmp(g_channels[i].name, channel) )
   continue;

  if ( !g_channels[i].clients[client] )
   return -1;

  c = &(g_channels[i]);
  break;
 }

 c->clients[client] = 0;
 c->client_count--;

 if ( !c->client_count ) {
  roar_mm_free(c->name);

  if ( c->topic.text != NULL )
   roar_mm_free(c->topic.text);
  if ( c->topic.user != NULL )
   roar_mm_free(c->topic.user);
 }

 return 0;
}

static int do_names(int client, const char * channel) {
 const char * nick = get_nick(client);
 size_t i;
 char buf[256];
 size_t len, offset;
 char * c_nick;
 int j;

 for (i = 0; i < MAX_CHANNELS; i++) {
  if ( !g_channels[i].client_count )
   continue;

  if ( !!strcasecmp(g_channels[i].name, channel) )
   continue;

  offset = 0;

  for (j = 0; j < ROAR_CLIENTS_MAX; j++) {
   if ( g_channels[i].clients[j] == 0 )
    continue;

   c_nick = get_nick(j);
   len = strlen(c_nick);
   if ( (offset + len + 3) > sizeof(buf) ) {
    buf[offset] = 0;
    put_printf(client, ":%s 353 %s = %s :%s\n", server_name, nick, channel, buf);
    offset = 0;
   }

   memcpy(buf + offset, c_nick, len);
   offset += len;
   buf[offset] = ' ';
   offset++;
   buf[offset] = 0;
  }

  if ( offset ) {
   buf[offset] = 0;
   put_printf(client, ":%s 353 %s = %s :%s\n", server_name, nick, channel, buf);
  }
  put_printf(client, ":%s 366 %s %s :End of /NAMES list.\n", server_name, nick, channel);

  return 0;
 }

 return -1;
}

static void cb_client_delete(struct roar_notify_core * core, struct roar_event * event, void * userdata) {
 int * listener;
 size_t count;
 struct channel * c;
 char * text = quit_msg;
 int client = event->target;
 const char * ufull = get_ufull(client);
 size_t i;

 (void)core, (void)userdata;

 if ( text == NULL ) {
  text = "Client deleted. Died, kicked or internal error.";
 }

 put_printf(client, "ERROR :Closing Link: %s (Quit: %s)\n", ufull, text);

  count = get_listener_list(client, NULL, &listener);
  for (; count; count--, listener++)
   put_printf(*listener, ":%s QUIT :Quit: %s\n", ufull, text);

 for (i = 0; i < MAX_CHANNELS; i++) {
  c = &(g_channels[i]);

  if ( !c->client_count )
   continue;

  if ( !c->clients[client] )
   continue;

  c->clients[client] = 0;
  c->client_count--;

  if ( !c->client_count ) {
   roar_mm_free(c->name);

   if ( c->topic.text != NULL )
    roar_mm_free(c->topic.text);
   if ( c->topic.user != NULL )
    roar_mm_free(c->topic.user);
  }
 }

 clients_flush(client);
}

static int new_client(int client, struct roar_vio_calls * vio, struct roard_listen * lsock) {
 struct roar_client_server * cs;
 char * name;

 (void)client, (void)vio, (void)lsock;

 clients_get_server(client, &cs);

 name = ROAR_CLIENT(cs)->name;
 snprintf(name, sizeof(ROAR_CLIENT(cs)->name), "Client%i~", client);

/*
:ph7.ph.sft NOTICE AUTH :*** Looking up your hostname...
:ph7.ph.sft NOTICE AUTH :*** Couldn't resolve your hostname; using your IP address instead
NICK nick
USER A B C D
:ph7.ph.sft NOTICE AUTH :*** Couldn't resolve your hostname; using your IP address instead
:ph7.ph.sft 002 nick :Your host is ph7.ph.sft, running version Unreal3.2.7
:ph7.ph.sft 003 nick :This server was created Tue Aug 28 2007 at 10:02:00 CEST
:ph7.ph.sft 004 nick ph7.ph.sft Unreal3.2.7 iowghraAsORTVSxNCWqBzvdHtGp lvhopsmntikrRcaqOALQbSeIKVfMCuzNTGj
:ph7.ph.sft 005 nick NAMESX SAFELIST HCN MAXCHANNELS=10 CHANLIMIT=#:10 MAXLIST=b:60,e:60,I:60 NICKLEN=30 CHANNELLEN=32 TOPICLEN=307 KICKLEN=307 AWAYLEN=307 MAXTARGETS=20 WALLCHOPS :are supported by this server
:ph7.ph.sft 005 nick WATCH=128 SILENCE=15 MODES=12 CHANTYPES=# PREFIX=(ohv)@%+ CHANMODES=beIqa,kfL,lj,psmntirRcOAQKVCuzNSMTG NETWORK=PH2 CASEMAPPING=ascii EXTBAN=~,cqnr ELIST=MNUCT STATUSMSG=@%+ EXCEPTS INVEX :are supported by this server
:ph7.ph.sft 005 nick CMDS=KNOCK,MAP,DCCALLOW,USERIP :are supported by this server
*/

 put_printf(client,
      ":%s 001 %s :Welcome to the roard based IRC server.\n"
      ":%s 375 %s :- %s Message of the Day -\n"
      ":%s 372 %s :- MotD goes here...\n"
      ":%s 376 %s :End of /MOTD command.\n",
   server_name, name,
   server_name, name, server_name,
   server_name, name,
   server_name, name
 );

 on_lusers(client, NULL, NULL, NULL);

 return 0;
}

static int check_client(int client, struct roar_vio_calls * vio) {
 struct roar_vio_calls     rvio;
 char cmd[1024*2];
 char * args;
 char * text;
 ssize_t len;
 size_t i;
 int found = 0;

 if ( vio == NULL ) {
  vio = &rvio;
  roar_vio_open_fh_socket(vio, clients_get_fh(client));
 }

 len = roar_vio_read(vio, cmd, sizeof(cmd)-1);
 if ( len < 1 ) {
  clients_delete(client);
  return -1;
 }

 cmd[len] = 0;

 strip_nl(cmd);

 ROAR_DBG("check_client(client=%i, vio=?): cmd=\"%s\"", client, cmd);

 if ( cmd[0] == 0 )
  return 0;

 args = strstr(cmd, " ");

 if ( args != NULL ) {
  *args = 0;
  args++;
  if ( *args == ':' ) {
   text = args + 1;
   args = NULL;
  } else {
   text = strstr(args, " :");
   if ( text != NULL ) {
    *text = 0;
    text += 2;
   }
  }
 } else {
  text = NULL;
 }

 for (i = 0; g_commands[i].name != NULL; i++) {
  if ( !strcasecmp(g_commands[i].name, cmd) ) {
   found = 1;
   g_commands[i].func(client, cmd, args, text);
  }
 }

 if ( !found ) {
  put_printf(client, ":%s 421 %s %s :Unknown command\n", server_name, get_nick(client), cmd);
 }

 return 0;
}

// commands:
static int on_nick(int client, const char * cmd, char * args, char * text) {
 char * nick = get_nick(client);
 int * listener;
 size_t count;
 const char * ufull;

 (void)cmd, (void)text;

 if ( args != NULL && args[0] != 0 && is_valid_name(args) && strlen(args) < ROAR_BUFFER_NAME ) {
  if ( get_client_by_nick(args) != -1 ) {
   put_printf(client, ":%s 433 %s %s :Nickname is already in use.\n", server_name, nick, args);
  } else {
   ufull = get_ufull(client);
   put_printf(client, ":%s NICK :%s\n", ufull, args);
   count = get_listener_list(client, NULL, &listener);
   for (; count; count--, listener++)
    if ( *listener != client )
     put_printf(*listener, ":%s NICK :%s\n", ufull, args);

   strcpy(nick, args);
  }
 } else {
  put_printf(client, ":%s 432 %s %s :Erroneous Nickname: Illegal characters\n", server_name, nick, args);
 }

 return 0;
}

static int on_user(int client, const char * cmd, char * args, char * text) {
 (void)client, (void)cmd, (void)args, (void)text;
 return 0;
}

static int on_quit(int client, const char * cmd, char * args, char * text) {
 int ret;

 (void)cmd, (void)args;

 if ( text == NULL )
  text = "... have a cuddle ...";

 quit_msg = text;
 ret = clients_delete(client);
 quit_msg = NULL;

 return ret;
}

static int on_ping(int client, const char * cmd, char * args, char * text) {
 (void)cmd, (void)args;

 put_printf(client, "PONG :%s\n", text);

 return 0;
}

static int on_lusers(int client, const char * cmd, char * args, char * text) {
 const char * clientnick = get_nick(client);
 size_t i;
 size_t numchans = 0;

 (void)cmd, (void)args, (void)text;

/*
:v0.fellig.org 251 nick :There are 9 users and 11 invisible on 1 servers

:v0.fellig.org 252 nick 1 :operator(s) online

:v0.fellig.org 254 nick 16 :channels formed
:v0.fellig.org 255 nick :I have 20 clients and 0 servers
:v0.fellig.org 265 nick :Current Local Users: 20  Max: 52
:v0.fellig.org 266 nick :Current Global Users: 20  Max: 22
*/

 for (i = 0; i < MAX_CHANNELS; i++) {
  if ( !g_channels[i].client_count )
   continue;
  numchans++;
 }

 put_printf(client, ":%s 251 %s :There are %zu users and 0 invisible on 1 servers\n",
            server_name, clientnick, counters_get(cur, clients));
 put_printf(client, ":%s 254 %s %zu :channels formed\n",
            server_name, clientnick, numchans);
 put_printf(client, ":%s 255 %s :I have %zu clients and 0 servers\n",
            server_name, clientnick, counters_get(cur, clients));
 put_printf(client, ":%s 265 %s :Current Local Users: %zu  Max: <unknown>\n",
            server_name, clientnick, counters_get(cur, clients));
 put_printf(client, ":%s 266 %s :Current Global Users: %zu  Max: <unknown>\n",
            server_name, clientnick, counters_get(cur, clients));

 return 0;
}

static int on_whois(int client, const char * cmd, char * args, char * text) {
 const char * clientnick = get_nick(client);
 const char * tnick = args;
 int tclient;

 (void)cmd, (void)text;

/*
:ph7.ph.sft 317 nick phi 131 1322456381 :seconds idle, signon time
*/

 if ( (tclient = get_client_by_nick(tnick)) == -1 ) {
  put_printf(client, ":%s 401 %s %s :No such nick/channel\n", server_name, clientnick, tnick);
 } else {
  put_printf(client, ":%s 311 %s %s %s %s * :%s\n", server_name, clientnick, tnick,
             get_ident(tclient), get_node(tclient), get_realname(tclient));
  put_printf(client, ":%s 312 %s %s %s :%s\n", server_name, clientnick, tnick, server_name, server_fullname);
 }
 put_printf(client, ":%s 318 %s %s :End of /WHOIS list.\n", server_name, clientnick, tnick);

 return 0;
}

static int on_privmsg(int client, const char * cmd, char * args, char * text) {
 const char * ufull = get_ufull(client);
 int * listener;
 size_t count;
 char * next;
 int tmp;

 if ( args == NULL || text == NULL )
  return -1;

 if ( text[0] == 0 )
  return 0;

 while (args != NULL) {
  next = strstr(args, ",");
  if ( next != NULL ) {
   *next = 0;
   next++;
  }

  if ( args[0] == '#' ) {
   count = get_listener_list(client, args, &listener);
   for (; count; count--, listener++)
    if ( *listener != client )
     put_printf(*listener, ":%s %s %s :%s\n", ufull, cmd, args, text);
  } else {
   if ( (tmp = get_client_by_nick(args)) == -1 ) {
    put_printf(client, ":%s 401 %s %s :No such nick/channel\n", server_name, get_nick(client), args);
   } else {
    put_printf(tmp, ":%s %s %s :%s\n", ufull, cmd, args, text);
   }
  }

  args = next;
 }

 return 0;
}


static int on_list(int client, const char * cmd, char * args, char * text) {
 const char * clientnick = get_nick(client);
 struct channel * c;
 size_t i;

 (void)cmd, (void)args, (void)text;

 put_printf(client, ":%s 321 %s Channel :Users  Name\n", server_name, clientnick);

 for (i = 0; i < MAX_CHANNELS; i++) {
  c = &(g_channels[i]);
  if ( !c->client_count )
   continue;

  put_printf(client, ":%s 322 %s %s %zu :[+] %s\n",
             server_name, clientnick, c->name, c->client_count, c->topic.text == NULL ? "" : c->topic.text);
 }

 put_printf(client, ":%s 323 %s :End of /LIST\n", server_name, clientnick);

 return 0;
}

static int on_join(int client, const char * cmd, char * args, char * text) {
 struct channel * c;
 const char * ufull = get_ufull(client);
 int * listener;
 size_t count;
 const char * nick;

 (void)cmd, (void)text;

 if ( args == NULL )
  return -1;

 if ( do_join(client, args) != 0 ) {
  return -1;
 }

 count = get_listener_list(client, args, &listener);
 for (; count; count--, listener++)
  put_printf(*listener, ":%s JOIN :%s\n", ufull, args);

 c = get_channel(args);

 if ( c->topic.text != NULL ) {
  nick = get_nick(client);
  put_printf(client, ":%s 332 %s %s :%s\n"
                     ":%s 333 %s %s %s %li\n",
         server_name, nick, c->name, c->topic.text,
         server_name, nick, c->name, c->topic.user, (long int)c->topic.ts
  );
 }

 do_names(client, args);

 return 0;
}

static int on_part(int client, const char * cmd, char * args, char * text) {
 const char * ufull = get_ufull(client);
 int * listener;
 size_t count;

 (void)cmd;

 if ( args == NULL )
  return -1;

 if ( text == NULL )
  text = "Dejoined.";

 count = get_listener_list(client, args, &listener);
 for (; count; count--, listener++)
  put_printf(*listener, ":%s PART %s :%s\n", ufull, args, text);

 do_part(client, args);

 return 0;
}

static int on_names(int client, const char * cmd, char * args, char * text) {
 (void)cmd, (void)text;

 if ( args == NULL )
  return -1;

 return do_names(client, args);
}

static int on_topic(int client, const char * cmd, char * args, char * text) {
 struct channel * c;
 const char * ufull = get_ufull(client);
 int * listener;
 size_t count;
 char * nick = get_nick(client);

 (void)cmd;

 if ( args == NULL )
  return -1;

 c = get_channel(args);

 if ( c == NULL )
  return -1;

 if ( !c->clients[client] ) {
  return -1;
 }

 if ( c->topic.text != NULL )
  roar_mm_free(c->topic.text);
 if ( c->topic.user != NULL )
  roar_mm_free(c->topic.user);

 c->topic.text = NULL;
 c->topic.user = roar_mm_strdup(nick);
 c->topic.ts   = time(NULL);

 if ( text != NULL )
  c->topic.text = roar_mm_strdup(text);

 if ( text == NULL )
  text = "";

 count = get_listener_list(client, c->name, &listener);
 for (; count; count--, listener++)
  put_printf(*listener, ":%s TOPIC %s :%s\n", ufull, c->name, text);

 return 0;
}

// plugin handling suff:

static int unload(struct roar_dl_librarypara * para, struct roar_dl_libraryinst * lib) {
 (void)para, (void)lib;

 roar_notify_core_unsubscribe(NULL, subscription_client_delete);

 return 0;
}

static struct roard_proto proto[1] = {
 {ROAR_PROTO_IRC, ROAR_SUBSYS_NONE, "Internet Relay Chat", NULL, new_client, check_client, NULL, NULL}
};

ROARD_DL_REG_PROTO(proto)

ROAR_DL_PLUGIN_START(roard_irc_protocol) {
 ROARD_DL_CHECK_VERSIONS();

 ROAR_DL_PLUGIN_META_PRODUCT_NIV("roard-irc-protocol", ROAR_VID_ROARAUDIO, ROAR_VNAME_ROARAUDIO);
 ROAR_DL_PLUGIN_META_VERSION(ROAR_VERSION_STRING);
 ROAR_DL_PLUGIN_META_LICENSE_TAG(GPLv3_0);
 ROAR_DL_PLUGIN_META_CONTACT_FLNE("Philipp", "Schafft", "ph3-der-loewe", "lion@lion.leolix.org");
 ROAR_DL_PLUGIN_META_DESC("Implementation of the Internet Relay Chat (IRC)");

 ROAR_DL_PLUGIN_REG_UNLOAD(unload);
 ROARD_DL_REGFN_PROTO();
 init();
} ROAR_DL_PLUGIN_END

//ll