8.2.x/src/parse.c

/*
 *  ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
 *
 *  Copyright (c) 1997-2019 ircd-hybrid development team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
 *  USA
 */

/*! \file parse.c
 * \brief The message parser.
 * \version $Id$
 */

#include "stdinc.h"
#include "client.h"
#include "parse.h"
#include "channel.h"
#include "hash.h"
#include "id.h"
#include "irc_string.h"
#include "ircd.h"
#include "numeric.h"
#include "log.h"
#include "send.h"
#include "conf.h"
#include "memory.h"
#include "user.h"
#include "server.h"
#include "packet.h"


/*
 * (based on orabidoo's parser code)
 *
 * This has always just been a trie. Look at volume III of Knuth ACP
 *
 *
 * ok, you start out with an array of pointers, each one corresponds
 * to a letter at the current position in the command being examined.
 *
 * so roughly you have this for matching 'trie' or 'tie'
 *
 * 't' points -> [MessageTree *] 'r' -> [MessageTree *] -> 'i'
 *   -> [MessageTree *] -> [MessageTree *] -> 'e' and matches
 *
 *                               'i' -> [MessageTree *] -> 'e' and matches
 *
 * BUGS (Limitations!)
 *
 * I designed this trie to parse ircd commands. Hence it currently
 * casefolds. This is trivial to fix by increasing MAXPTRLEN.
 * This trie also "folds" '{' etc. down. This means, the input to this
 * trie must be alpha tokens only. This again, is a limitation that
 * can be overcome by increasing MAXPTRLEN to include upper/lower case
 * at the expense of more memory. At the extreme end, you could make
 * MAXPTRLEN 128.
 *
 * This is also not a patricia trie. On short ircd tokens, this is
 * not likely going to matter.
 *
 * Diane Bruce (Dianora), June 6 2003
 */

/*
 * Must be a power of 2, and larger than 26 [a-z]|[A-Z]. It's used to allocate
 * the set of pointers at each node of the tree.
 * There are MAXPTRLEN pointers at each node. Obviously, there have to be more
 * pointers than ASCII letters. 32 is a nice number since there is then no need
 * to shift 'A'/'a' to base 0 index, at the expense of a few never used
 * pointers.
 * For a small parser like this, this is a good compromise and does
 * make it somewhat faster. - Dianora
 */
enum { MAXPTRLEN = 32 };


static struct MessageTree
{
  int links; /* Count of all pointers (including msg) at this node
              * used as reference count for deletion of _this_ node.
              */
  struct Message *msg;
  struct MessageTree *pointers[MAXPTRLEN];
} msg_tree;


/* remove_unknown()
 *
 * inputs       -
 * output       -
 * side effects -
 */
static void
parse_remove_unknown(struct Client *client_p, const char *lsender, char *lbuffer)
{
  /*
   * Do kill if it came from a server because it means there is a ghost
   * user on the other server which needs to be removed. -avalon
   * Tell opers about this. -Taner
   */
  /*
   * '[0-9]something'  is an ID      (KILL/SQUIT depending on its length)
   * 'nodots'          is a nickname (KILL)
   * 'no.dot.at.start' is a server   (SQUIT)
   */
  if ((IsDigit(*lsender) && strlen(lsender) <= IRC_MAXSID) || strchr(lsender, '.'))
  {
    sendto_realops_flags(UMODE_DEBUG, L_ADMIN, SEND_NOTICE,
                         "Unknown prefix (%s) from %s, Squitting %s",
                         lbuffer, client_get_name(client_p, SHOW_IP), lsender);
    sendto_realops_flags(UMODE_DEBUG, L_OPER, SEND_NOTICE,
                         "Unknown prefix (%s) from %s, Squitting %s",
                         lbuffer, client_get_name(client_p, MASK_IP), lsender);
    sendto_one(client_p, ":%s SQUIT %s :(Unknown prefix (%s) from %s)",
               me.id, lsender, lbuffer, client_p->name);
  }
  else
    sendto_one(client_p, ":%s KILL %s :%s (Unknown Client)",
               me.id, lsender, me.name);
}

/*
 *
 *      parc    number of arguments ('sender' counted as one!)
 *      parv[0] pointer to 'sender' (may point to empty string) (not used)
 *      parv[1]..parv[parc-1]
 *              pointers to additional parameters, this is a NULL
 *              terminated list (parv[parc] == NULL).
 *
 * *WARNING*
 *      Numerics are mostly error reports. If there is something
 *      wrong with the message, just *DROP* it! Don't even think of
 *      sending back a neat error message -- big danger of creating
 *      a ping pong error message...
 *
 * Rewritten by Nemesi, Jan 1999, to support numeric nicks in parv[1]
 *
 * Called when we get a numeric message from a remote _server_ and we are
 * supposed to forward it somewhere. Note that we always ignore numerics sent
 * to 'me' and simply drop the message if we can't handle with this properly:
 * the savvy approach is NEVER generate an error in response to an... error :)
 */
static void
parse_handle_numeric(unsigned int numeric, struct Client *source_p, int parc, char *parv[])
{
  struct Client *target_p = NULL;
  struct Channel *chptr = NULL;

  /*
   * Avoid trash, we need it to come from a server and have a target
   */
  if (parc < 2 || !IsServer(source_p))
    return;

  /*
   * Who should receive this message ? Will we do something with it ?
   * Note that we use findUser functions, so the target can't be neither
   * a server, nor a channel (?) nor a list of targets (?) .. u2.10
   * should never generate numeric replies to non-users anyway
   * Ahem... it can be a channel actually, csc bots use it :\ --Nem
   */
  if (IsChanPrefix(*parv[1]))
    chptr = hash_find_channel(parv[1]);
  else
    target_p = find_person(source_p, parv[1]);

  if ((target_p == NULL || target_p->from == source_p->from) && chptr == NULL)
    return;

  /*
   * Remap low number numerics, not that I understand WHY.. --Nemesi
   */
  /*
   * Numerics below 100 talk about the current 'connection', you're not
   * connected to a remote server so it doesn't make sense to send them
   * remotely - but the information they contain may be useful, so we
   * remap them up. Weird, but true.  -- Isomer
   */
  if (numeric < 100)
    numeric += 100;

  if (target_p)
  {
    /* Fake it for server hiding, if it's our client */
    if ((ConfigServerHide.hide_servers || IsHidden(source_p)) && MyConnect(target_p) &&
        !HasUMode(target_p, UMODE_OPER))
      sendto_one_numeric(target_p, &me, numeric | SND_EXPLICIT, "%s", parv[2]);
    else
      sendto_one_numeric(target_p, source_p, numeric | SND_EXPLICIT, "%s", parv[2]);
  }
  else
    sendto_channel_butone(source_p, source_p, chptr, 0, "%u %s %s",
                          numeric, chptr->name, parv[2]);
}

/* handle_command()
 *
 * inputs       - pointer to message block
 *              - pointer to client
 *              - pointer to client message is from
 *              - count of number of args
 *              - pointer to argv[] array
 * output       - -1 if error from server
 * side effects -
 */
static void
parse_handle_command(struct Message *message, struct Client *source_p,
                     unsigned int i, char *para[])
{
  if (IsServer(source_p->from))
    ++message->rcount;
  ++message->count;

  if (MyClient(source_p) && (message->flags & MFLG_ENDGRACE))
    flood_endgrace(source_p);

  /* Check right amount of parameters is passed... --is */
  if (i < message->args_min)
    sendto_one_numeric(source_p, &me, ERR_NEEDMOREPARAMS, message->cmd);
  else
    message->handlers[source_p->from->handler](source_p, i, para);
}

/*
 * parse a buffer.
 *
 * NOTE: parse() should not be called recusively by any other functions!
 */
void
parse(struct Client *client_p, char *pbuffer, char *bufend)
{
  struct Client *from = client_p;
  struct Message *message = NULL;
  char *para[MAXPARA + 2];  /* <command> + <parameters> + NULL */
  char *ch = NULL;
  char *s = NULL;
  unsigned int numeric = 0;
  unsigned int parc = 0;
  unsigned int paramcount;

  if (IsDefunct(client_p))
    return;

  assert(client_p->connection);
  assert(client_p->connection->fd);
  assert(client_p->connection->fd->flags.open);


  assert((bufend - pbuffer) < IRCD_BUFSIZE);

  for (ch = pbuffer; *ch == ' '; ++ch)  /* Skip spaces */
    ;

  if (*ch == ':')
  {
    /*
     * Copy the prefix to 'sender' assuming it terminates
     * with SPACE (or NULL, which is an error, though).
     */
    const char *const sender = ++ch;

    if ((s = strchr(ch, ' ')))
    {
      *s = '\0';
      ch = ++s;
    }

    if (*sender && IsServer(client_p))
    {
      if ((from = hash_find_id(sender)) == NULL)
        from = hash_find_client(sender);

      /*
       * Hmm! If the client corresponding to the prefix is not found--what is
       * the correct action??? Now, I will ignore the message (old IRC just
       * let it through as if the prefix just wasn't there...) --msa
       */
      if (from == NULL)
      {
        ++ServerStats.is_unpf;
        parse_remove_unknown(client_p, sender, pbuffer);
        return;
      }

      if (from->from != client_p)
      {
        ++ServerStats.is_wrdi;
        sendto_realops_flags(UMODE_DEBUG, L_ADMIN, SEND_NOTICE,
                             "Fake direction: dropped message from %s[%s] via %s",
                             from->name, from->from->name,
                             client_get_name(client_p, SHOW_IP));
        sendto_realops_flags(UMODE_DEBUG, L_OPER, SEND_NOTICE,
                             "Fake direction: dropped message from %s[%s] via %s",
                             from->name, from->from->name,
                             client_get_name(client_p, MASK_IP));
        return;
      }
    }

    while (*ch == ' ')
      ++ch;
  }

  if (*ch == '\0')
  {
    ++ServerStats.is_empt;
    return;
  }

  /*
   * Extract the command code from the packet. Point s to the end
   * of the command code and calculate the length using pointer
   * arithmetic. Note: only need length for numerics and *all*
   * numerics must have parameters and thus a space after the command
   * code. -avalon
   */

  /* EOB is 3 characters long but is not a numeric */
  if (*(ch + 3) == ' ' &&  /* Ok, let's see if it's a possible numeric */
      IsDigit(*ch) && IsDigit(*(ch + 1)) && IsDigit(*(ch + 2)))
  {
    numeric = (*ch - '0') * 100 + (*(ch + 1) - '0') * 10 + (*(ch + 2) - '0');
    paramcount = 2;  /* Destination, and the rest of it */
    ++ServerStats.is_num;
    s = ch + 3;  /* I know this is ' ' from above if */
    *s++ = '\0';  /* Blow away the ' ', and point s to next part */
  }
  else
  {
    if ((s = strchr(ch, ' ')))
      *s++ = '\0';

    if ((message = find_command(ch)) == NULL)
    {
      /*
       * Note: Give error message *only* to recognized
       * persons. It's a nightmare situation to have
       * two programs sending "Unknown command"'s or
       * equivalent to each other at full blast....
       * If it has got to person state, it at least
       * seems to be well behaving. Perhaps this message
       * should never be generated, though...  --msa
       * Hm, when is the buffer empty -- if a command
       * code has been found ?? -Armin
       */
      if (*pbuffer)
        if (IsClient(from))
          sendto_one_numeric(from, &me, ERR_UNKNOWNCOMMAND, ch);

      ++ServerStats.is_unco;
      return;
    }

    assert(message->cmd);

    paramcount = message->args_max;

    size_t length = bufend - ((s) ? s : ch);
    message->bytes += length;
  }

  /*
   * Must the following loop really be so devious? On surface it
   * splits the message to parameters from blank spaces. But, if
   * paramcount has been reached, the rest of the message goes into
   * this last parameter (about same effect as ":" has...) --msa
   */

  /* Note initially true: s == NULL || *(s - 1) == '\0' !! */

  para[parc] = ch;

  if (message && (message->flags & MFLG_EXTRA))
  {
    /*
     * XXX: This will have to go away after the command handler rewrite
     */
    para[++parc] = message->extra;
  }

  if (s)
  {
    if (paramcount > MAXPARA)
      paramcount = MAXPARA;

    while (true)
    {
       while (*s == ' ')
         *s++ = '\0';

       if (*s == '\0')
         break;

       if (*s == ':')
       {
         /* The rest is single parameter--can include blanks also. */
         para[++parc] = s + (numeric == 0);  /* Keep the colon if it's a numeric */
         break;
       }

       para[++parc] = s;

       if (parc >= paramcount)
         break;

       while (*s && *s != ' ')
         ++s;
    }
  }

  para[++parc] = NULL;

  if (message)
    parse_handle_command(message, from, parc, para);
  else
    parse_handle_numeric(numeric, from, parc, para);
}

/* add_msg_element()
 *
 * inputs       - pointer to MessageTree
 *              - pointer to Message to add for given command
 *              - pointer to current portion of command being added
 * output       - NONE
 * side effects - recursively build the Message Tree ;-)
 */
/*
 * How this works.
 *
 * The code first checks to see if its reached the end of the command
 * If so, that struct MessageTree has a msg pointer updated and the links
 * count incremented, since a msg pointer is a reference.
 * Then the code descends recursively, building the trie.
 * If a pointer index inside the struct MessageTree is NULL a new
 * child struct MessageTree has to be allocated.
 * The links (reference count) is incremented as they are created
 * in the parent.
 */
static void
add_msg_element(struct MessageTree *mtree_p, struct Message *msg_p,
                const char *cmd)
{
  struct MessageTree *ntree_p = NULL;

  if (*cmd == '\0')
  {
    mtree_p->msg = msg_p;
    mtree_p->links++;  /* Have msg pointer, so up ref count */
  }
  else
  {
    /*
     * *cmd & (MAXPTRLEN-1)
     * convert the char pointed to at *cmd from ASCII to an integer
     * between 0 and MAXPTRLEN.
     * Thus 'A' -> 0x1 'B' -> 0x2 'c' -> 0x3 etc.
     */
    if ((ntree_p = mtree_p->pointers[*cmd & (MAXPTRLEN - 1)]) == NULL)
    {
      ntree_p = xcalloc(sizeof(*ntree_p));
      mtree_p->pointers[*cmd & (MAXPTRLEN - 1)] = ntree_p;

      mtree_p->links++;  /* Have new pointer, so up ref count */
    }

    add_msg_element(ntree_p, msg_p, cmd + 1);
  }
}

/* del_msg_element()
 *
 * inputs       - Pointer to MessageTree to delete from
 *              - pointer to command name to delete
 * output       - NONE
 * side effects - recursively deletes a token from the Message Tree ;-)
 */
/*
 * How this works.
 *
 * Well, first off, the code recursively descends into the trie
 * until it finds the terminating letter of the command being removed.
 * Once it has done that, it marks the msg pointer as NULL then
 * reduces the reference count on that allocated struct MessageTree
 * since a command counts as a reference.
 *
 * Then it pops up the recurse stack. As it comes back up the recurse
 * The code checks to see if the child now has no pointers or msg
 * i.e. the links count has gone to zero. If it's no longer used, the
 * child struct MessageTree can be deleted. The parent reference
 * to this child is then removed and the parents link count goes down.
 * Thus, we continue to go back up removing all unused MessageTree(s)
 */
static void
del_msg_element(struct MessageTree *mtree_p, const char *cmd)
{
  struct MessageTree *ntree_p = NULL;

  /*
   * In case this is called for a nonexistent command
   * check that there is a msg pointer here, else links-- goes -ve
   * -db
   */
  if (*cmd == '\0' && mtree_p->msg)
  {
    mtree_p->msg = NULL;
    mtree_p->links--;
  }
  else
  {
    if ((ntree_p = mtree_p->pointers[*cmd & (MAXPTRLEN - 1)]))
    {
      del_msg_element(ntree_p, cmd + 1);

      if (ntree_p->links == 0)
      {
        mtree_p->pointers[*cmd & (MAXPTRLEN - 1)] = NULL;
        mtree_p->links--;
        xfree(ntree_p);
      }
    }
  }
}

/* msg_tree_parse()
 *
 * inputs       - Pointer to command to find
 *              - Pointer to MessageTree root
 * output       - Find given command returning Message * if found NULL if not
 * side effects - none
 */
static struct Message *
msg_tree_parse(const char *cmd)
{
  struct MessageTree *mtree = &msg_tree;

  assert(!EmptyString(cmd));

  while (IsAlpha(*cmd) && (mtree = mtree->pointers[*cmd & (MAXPTRLEN - 1)]))
    if (*++cmd == '\0')
      return mtree->msg;

  return NULL;
}

/* mod_add_cmd()
 *
 * inputs       - pointer to struct Message
 * output       - none
 * side effects - load this one command name
 */
void
mod_add_cmd(struct Message *msg)
{
  assert(msg);
  assert(msg->cmd);

  /* Command already added? */
  if (msg_tree_parse(msg->cmd) == NULL)
    add_msg_element(&msg_tree, msg, msg->cmd);
}

/* mod_del_cmd()
 *
 * inputs       - pointer to struct Message
 * output       - none
 * side effects - unload this one command name
 */
void
mod_del_cmd(struct Message *msg)
{
  assert(msg);
  assert(msg->cmd);

  if (msg_tree_parse(msg->cmd))
    del_msg_element(&msg_tree, msg->cmd);
}

/* find_command()
 *
 * inputs       - command name
 * output       - pointer to struct Message
 * side effects - none
 */
struct Message *
find_command(const char *cmd)
{
  return msg_tree_parse(cmd);
}

static void
recurse_report_messages(struct Client *source_p, const struct MessageTree *mtree)
{
  if (mtree->msg)
    sendto_one_numeric(source_p, &me, RPL_STATSCOMMANDS,
                       mtree->msg->cmd,
                       mtree->msg->count, mtree->msg->bytes,
                       mtree->msg->rcount);

  for (unsigned int i = 0; i < MAXPTRLEN; ++i)
    if (mtree->pointers[i])
      recurse_report_messages(source_p, mtree->pointers[i]);
}

/* report_messages()
 *
 * inputs       - pointer to client to report to
 * output       - NONE
 * side effects - client is shown list of commands
 */
void
report_messages(struct Client *source_p)
{
  const struct MessageTree *const mtree = &msg_tree;

  for (unsigned int i = 0; i < MAXPTRLEN; ++i)
    if (mtree->pointers[i])
      recurse_report_messages(source_p, mtree->pointers[i]);
}

/* m_not_oper()
 * inputs       -
 * output       -
 * side effects - just returns a nastyogram to given user
 */
int
m_not_oper(struct Client *source_p, int parc, char *parv[])
{
  sendto_one_numeric(source_p, &me, ERR_NOPRIVILEGES);
  return 0;
}

int
m_unregistered(struct Client *source_p, int parc, char *parv[])
{
  sendto_one_numeric(source_p, &me, ERR_NOTREGISTERED);
  return 0;
}

int
m_registered(struct Client *source_p, int parc, char *parv[])
{
  sendto_one_numeric(source_p, &me, ERR_ALREADYREGISTRED);
  return 0;
}

int
m_ignore(struct Client *source_p, int parc, char *parv[])
{
  return 0;
}
Revision:	8751
Committed:	Tue Jan 1 11:06:50 2019 UTC (5 years, 3 months ago) by michael
Content type:	text/x-csrc
File size:	18958 byte(s)
Log Message:	- Update copyright years
#	Content
1	/*
2	* ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
3	*
4	* Copyright (c) 1997-2019 ircd-hybrid development team
5	*
6	* This program is free software; you can redistribute it and/or modify
7	* it under the terms of the GNU General Public License as published by
8	* the Free Software Foundation; either version 2 of the License, or
9	* (at your option) any later version.
10	*
11	* This program is distributed in the hope that it will be useful,
12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14	* GNU General Public License for more details.
15	*
16	* You should have received a copy of the GNU General Public License
17	* along with this program; if not, write to the Free Software
18	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
19	* USA
20	*/
21
22	/*! \file parse.c
23	* \brief The message parser.
24	* \version $Id$
25	*/
26
27	#include "stdinc.h"
28	#include "client.h"
29	#include "parse.h"
30	#include "channel.h"
31	#include "hash.h"
32	#include "id.h"
33	#include "irc_string.h"
34	#include "ircd.h"
35	#include "numeric.h"
36	#include "log.h"
37	#include "send.h"
38	#include "conf.h"
39	#include "memory.h"
40	#include "user.h"
41	#include "server.h"
42	#include "packet.h"
43
44
45	/*
46	* (based on orabidoo's parser code)
47	*
48	* This has always just been a trie. Look at volume III of Knuth ACP
49	*
50	*
51	* ok, you start out with an array of pointers, each one corresponds
52	* to a letter at the current position in the command being examined.
53	*
54	* so roughly you have this for matching 'trie' or 'tie'
55	*
56	* 't' points -> [MessageTree ] 'r' -> [MessageTree ] -> 'i'
57	* -> [MessageTree ] -> [MessageTree ] -> 'e' and matches
58	*
59	* 'i' -> [MessageTree *] -> 'e' and matches
60	*
61	* BUGS (Limitations!)
62	*
63	* I designed this trie to parse ircd commands. Hence it currently
64	* casefolds. This is trivial to fix by increasing MAXPTRLEN.
65	* This trie also "folds" '{' etc. down. This means, the input to this
66	* trie must be alpha tokens only. This again, is a limitation that
67	* can be overcome by increasing MAXPTRLEN to include upper/lower case
68	* at the expense of more memory. At the extreme end, you could make
69	* MAXPTRLEN 128.
70	*
71	* This is also not a patricia trie. On short ircd tokens, this is
72	* not likely going to matter.
73	*
74	* Diane Bruce (Dianora), June 6 2003
75	*/
76
77	/*
78	* Must be a power of 2, and larger than 26 [a-z]\|[A-Z]. It's used to allocate
79	* the set of pointers at each node of the tree.
80	* There are MAXPTRLEN pointers at each node. Obviously, there have to be more
81	* pointers than ASCII letters. 32 is a nice number since there is then no need
82	* to shift 'A'/'a' to base 0 index, at the expense of a few never used
83	* pointers.
84	* For a small parser like this, this is a good compromise and does
85	* make it somewhat faster. - Dianora
86	*/
87	enum { MAXPTRLEN = 32 };
88
89
90	static struct MessageTree
91	{
92	int links; /* Count of all pointers (including msg) at this node
93	* used as reference count for deletion of _this_ node.
94	*/
95	struct Message *msg;
96	struct MessageTree *pointers[MAXPTRLEN];
97	} msg_tree;
98
99
100	/* remove_unknown()
101	*
102	* inputs -
103	* output -
104	* side effects -
105	*/
106	static void
107	parse_remove_unknown(struct Client client_p, const char lsender, char *lbuffer)
108	{
109	/*
110	* Do kill if it came from a server because it means there is a ghost
111	* user on the other server which needs to be removed. -avalon
112	* Tell opers about this. -Taner
113	*/
114	/*
115	* '[0-9]something' is an ID (KILL/SQUIT depending on its length)
116	* 'nodots' is a nickname (KILL)
117	* 'no.dot.at.start' is a server (SQUIT)
118	*/
119	if ((IsDigit(*lsender) && strlen(lsender) <= IRC_MAXSID) \|\| strchr(lsender, '.'))
120	{
121	sendto_realops_flags(UMODE_DEBUG, L_ADMIN, SEND_NOTICE,
122	"Unknown prefix (%s) from %s, Squitting %s",
123	lbuffer, client_get_name(client_p, SHOW_IP), lsender);
124	sendto_realops_flags(UMODE_DEBUG, L_OPER, SEND_NOTICE,
125	"Unknown prefix (%s) from %s, Squitting %s",
126	lbuffer, client_get_name(client_p, MASK_IP), lsender);
127	sendto_one(client_p, ":%s SQUIT %s :(Unknown prefix (%s) from %s)",
128	me.id, lsender, lbuffer, client_p->name);
129	}
130	else
131	sendto_one(client_p, ":%s KILL %s :%s (Unknown Client)",
132	me.id, lsender, me.name);
133	}
134
135	/*
136	*
137	* parc number of arguments ('sender' counted as one!)
138	* parv[0] pointer to 'sender' (may point to empty string) (not used)
139	* parv[1]..parv[parc-1]
140	* pointers to additional parameters, this is a NULL
141	* terminated list (parv[parc] == NULL).
142	*
143	* WARNING
144	* Numerics are mostly error reports. If there is something
145	* wrong with the message, just DROP it! Don't even think of
146	* sending back a neat error message -- big danger of creating
147	* a ping pong error message...
148	*
149	* Rewritten by Nemesi, Jan 1999, to support numeric nicks in parv[1]
150	*
151	* Called when we get a numeric message from a remote _server_ and we are
152	* supposed to forward it somewhere. Note that we always ignore numerics sent
153	* to 'me' and simply drop the message if we can't handle with this properly:
154	* the savvy approach is NEVER generate an error in response to an... error :)
155	*/
156	static void
157	parse_handle_numeric(unsigned int numeric, struct Client source_p, int parc, char parv[])
158	{
159	struct Client *target_p = NULL;
160	struct Channel *chptr = NULL;
161
162	/*
163	* Avoid trash, we need it to come from a server and have a target
164	*/
165	if (parc < 2 \|\| !IsServer(source_p))
166	return;
167
168	/*
169	* Who should receive this message ? Will we do something with it ?
170	* Note that we use findUser functions, so the target can't be neither
171	* a server, nor a channel (?) nor a list of targets (?) .. u2.10
172	* should never generate numeric replies to non-users anyway
173	* Ahem... it can be a channel actually, csc bots use it :\ --Nem
174	*/
175	if (IsChanPrefix(*parv[1]))
176	chptr = hash_find_channel(parv[1]);
177	else
178	target_p = find_person(source_p, parv[1]);
179
180	if ((target_p == NULL \|\| target_p->from == source_p->from) && chptr == NULL)
181	return;
182
183	/*
184	* Remap low number numerics, not that I understand WHY.. --Nemesi
185	*/
186	/*
187	* Numerics below 100 talk about the current 'connection', you're not
188	* connected to a remote server so it doesn't make sense to send them
189	* remotely - but the information they contain may be useful, so we
190	* remap them up. Weird, but true. -- Isomer
191	*/
192	if (numeric < 100)
193	numeric += 100;
194
195	if (target_p)
196	{
197	/* Fake it for server hiding, if it's our client */
198	if ((ConfigServerHide.hide_servers \|\| IsHidden(source_p)) && MyConnect(target_p) &&
199	!HasUMode(target_p, UMODE_OPER))
200	sendto_one_numeric(target_p, &me, numeric \| SND_EXPLICIT, "%s", parv[2]);
201	else
202	sendto_one_numeric(target_p, source_p, numeric \| SND_EXPLICIT, "%s", parv[2]);
203	}
204	else
205	sendto_channel_butone(source_p, source_p, chptr, 0, "%u %s %s",
206	numeric, chptr->name, parv[2]);
207	}
208
209	/* handle_command()
210	*
211	* inputs - pointer to message block
212	* - pointer to client
213	* - pointer to client message is from
214	* - count of number of args
215	* - pointer to argv[] array
216	* output - -1 if error from server
217	* side effects -
218	*/
219	static void
220	parse_handle_command(struct Message message, struct Client source_p,
221	unsigned int i, char *para[])
222	{
223	if (IsServer(source_p->from))
224	++message->rcount;
225	++message->count;
226
227	if (MyClient(source_p) && (message->flags & MFLG_ENDGRACE))
228	flood_endgrace(source_p);
229
230	/* Check right amount of parameters is passed... --is */
231	if (i < message->args_min)
232	sendto_one_numeric(source_p, &me, ERR_NEEDMOREPARAMS, message->cmd);
233	else
234	message->handlers[source_p->from->handler](source_p, i, para);
235	}
236
237	/*
238	* parse a buffer.
239	*
240	* NOTE: parse() should not be called recusively by any other functions!
241	*/
242	void
243	parse(struct Client client_p, char pbuffer, char *bufend)
244	{
245	struct Client *from = client_p;
246	struct Message *message = NULL;
247	char para[MAXPARA + 2]; / <command> + <parameters> + NULL */
248	char *ch = NULL;
249	char *s = NULL;
250	unsigned int numeric = 0;
251	unsigned int parc = 0;
252	unsigned int paramcount;
253
254	if (IsDefunct(client_p))
255	return;
256
257	assert(client_p->connection);
258	assert(client_p->connection->fd);
259	assert(client_p->connection->fd->flags.open);
260
261
262	assert((bufend - pbuffer) < IRCD_BUFSIZE);
263
264	for (ch = pbuffer; ch == ' '; ++ch) / Skip spaces */
265	;
266
267	if (*ch == ':')
268	{
269	/*
270	* Copy the prefix to 'sender' assuming it terminates
271	* with SPACE (or NULL, which is an error, though).
272	*/
273	const char *const sender = ++ch;
274
275	if ((s = strchr(ch, ' ')))
276	{
277	*s = '\0';
278	ch = ++s;
279	}
280
281	if (*sender && IsServer(client_p))
282	{
283	if ((from = hash_find_id(sender)) == NULL)
284	from = hash_find_client(sender);
285
286	/*
287	* Hmm! If the client corresponding to the prefix is not found--what is
288	* the correct action??? Now, I will ignore the message (old IRC just
289	* let it through as if the prefix just wasn't there...) --msa
290	*/
291	if (from == NULL)
292	{
293	++ServerStats.is_unpf;
294	parse_remove_unknown(client_p, sender, pbuffer);
295	return;
296	}
297
298	if (from->from != client_p)
299	{
300	++ServerStats.is_wrdi;
301	sendto_realops_flags(UMODE_DEBUG, L_ADMIN, SEND_NOTICE,
302	"Fake direction: dropped message from %s[%s] via %s",
303	from->name, from->from->name,
304	client_get_name(client_p, SHOW_IP));
305	sendto_realops_flags(UMODE_DEBUG, L_OPER, SEND_NOTICE,
306	"Fake direction: dropped message from %s[%s] via %s",
307	from->name, from->from->name,
308	client_get_name(client_p, MASK_IP));
309	return;
310	}
311	}
312
313	while (*ch == ' ')
314	++ch;
315	}
316
317	if (*ch == '\0')
318	{
319	++ServerStats.is_empt;
320	return;
321	}
322
323	/*
324	* Extract the command code from the packet. Point s to the end
325	* of the command code and calculate the length using pointer
326	* arithmetic. Note: only need length for numerics and all
327	* numerics must have parameters and thus a space after the command
328	* code. -avalon
329	*/
330
331	/* EOB is 3 characters long but is not a numeric */
332	if ((ch + 3) == ' ' && / Ok, let's see if it's a possible numeric */
333	IsDigit(ch) && IsDigit((ch + 1)) && IsDigit(*(ch + 2)))
334	{
335	numeric = (ch - '0') 100 + ((ch + 1) - '0') 10 + (*(ch + 2) - '0');
336	paramcount = 2; /* Destination, and the rest of it */
337	++ServerStats.is_num;
338	s = ch + 3; /* I know this is ' ' from above if */
339	s++ = '\0'; / Blow away the ' ', and point s to next part */
340	}
341	else
342	{
343	if ((s = strchr(ch, ' ')))
344	*s++ = '\0';
345
346	if ((message = find_command(ch)) == NULL)
347	{
348	/*
349	* Note: Give error message only to recognized
350	* persons. It's a nightmare situation to have
351	* two programs sending "Unknown command"'s or
352	* equivalent to each other at full blast....
353	* If it has got to person state, it at least
354	* seems to be well behaving. Perhaps this message
355	* should never be generated, though... --msa
356	* Hm, when is the buffer empty -- if a command
357	* code has been found ?? -Armin
358	*/
359	if (*pbuffer)
360	if (IsClient(from))
361	sendto_one_numeric(from, &me, ERR_UNKNOWNCOMMAND, ch);
362
363	++ServerStats.is_unco;
364	return;
365	}
366
367	assert(message->cmd);
368
369	paramcount = message->args_max;
370
371	size_t length = bufend - ((s) ? s : ch);
372	message->bytes += length;
373	}
374
375	/*
376	* Must the following loop really be so devious? On surface it
377	* splits the message to parameters from blank spaces. But, if
378	* paramcount has been reached, the rest of the message goes into
379	* this last parameter (about same effect as ":" has...) --msa
380	*/
381
382	/* Note initially true: s == NULL \|\| (s - 1) == '\0' !! /
383
384	para[parc] = ch;
385
386	if (message && (message->flags & MFLG_EXTRA))
387	{
388	/*
389	* XXX: This will have to go away after the command handler rewrite
390	*/
391	para[++parc] = message->extra;
392	}
393
394	if (s)
395	{
396	if (paramcount > MAXPARA)
397	paramcount = MAXPARA;
398
399	while (true)
400	{
401	while (*s == ' ')
402	*s++ = '\0';
403
404	if (*s == '\0')
405	break;
406
407	if (*s == ':')
408	{
409	/* The rest is single parameter--can include blanks also. */
410	para[++parc] = s + (numeric == 0); /* Keep the colon if it's a numeric */
411	break;
412	}
413
414	para[++parc] = s;
415
416	if (parc >= paramcount)
417	break;
418
419	while (s && s != ' ')
420	++s;
421	}
422	}
423
424	para[++parc] = NULL;
425
426	if (message)
427	parse_handle_command(message, from, parc, para);
428	else
429	parse_handle_numeric(numeric, from, parc, para);
430	}
431
432	/* add_msg_element()
433	*
434	* inputs - pointer to MessageTree
435	* - pointer to Message to add for given command
436	* - pointer to current portion of command being added
437	* output - NONE
438	* side effects - recursively build the Message Tree ;-)
439	*/
440	/*
441	* How this works.
442	*
443	* The code first checks to see if its reached the end of the command
444	* If so, that struct MessageTree has a msg pointer updated and the links
445	* count incremented, since a msg pointer is a reference.
446	* Then the code descends recursively, building the trie.
447	* If a pointer index inside the struct MessageTree is NULL a new
448	* child struct MessageTree has to be allocated.
449	* The links (reference count) is incremented as they are created
450	* in the parent.
451	*/
452	static void
453	add_msg_element(struct MessageTree mtree_p, struct Message msg_p,
454	const char *cmd)
455	{
456	struct MessageTree *ntree_p = NULL;
457
458	if (*cmd == '\0')
459	{
460	mtree_p->msg = msg_p;
461	mtree_p->links++; /* Have msg pointer, so up ref count */
462	}
463	else
464	{
465	/*
466	* *cmd & (MAXPTRLEN-1)
467	* convert the char pointed to at *cmd from ASCII to an integer
468	* between 0 and MAXPTRLEN.
469	* Thus 'A' -> 0x1 'B' -> 0x2 'c' -> 0x3 etc.
470	*/
471	if ((ntree_p = mtree_p->pointers[*cmd & (MAXPTRLEN - 1)]) == NULL)
472	{
473	ntree_p = xcalloc(sizeof(*ntree_p));
474	mtree_p->pointers[*cmd & (MAXPTRLEN - 1)] = ntree_p;
475
476	mtree_p->links++; /* Have new pointer, so up ref count */
477	}
478
479	add_msg_element(ntree_p, msg_p, cmd + 1);
480	}
481	}
482
483	/* del_msg_element()
484	*
485	* inputs - Pointer to MessageTree to delete from
486	* - pointer to command name to delete
487	* output - NONE
488	* side effects - recursively deletes a token from the Message Tree ;-)
489	*/
490	/*
491	* How this works.
492	*
493	* Well, first off, the code recursively descends into the trie
494	* until it finds the terminating letter of the command being removed.
495	* Once it has done that, it marks the msg pointer as NULL then
496	* reduces the reference count on that allocated struct MessageTree
497	* since a command counts as a reference.
498	*
499	* Then it pops up the recurse stack. As it comes back up the recurse
500	* The code checks to see if the child now has no pointers or msg
501	* i.e. the links count has gone to zero. If it's no longer used, the
502	* child struct MessageTree can be deleted. The parent reference
503	* to this child is then removed and the parents link count goes down.
504	* Thus, we continue to go back up removing all unused MessageTree(s)
505	*/
506	static void
507	del_msg_element(struct MessageTree mtree_p, const char cmd)
508	{
509	struct MessageTree *ntree_p = NULL;
510
511	/*
512	* In case this is called for a nonexistent command
513	* check that there is a msg pointer here, else links-- goes -ve
514	* -db
515	*/
516	if (*cmd == '\0' && mtree_p->msg)
517	{
518	mtree_p->msg = NULL;
519	mtree_p->links--;
520	}
521	else
522	{
523	if ((ntree_p = mtree_p->pointers[*cmd & (MAXPTRLEN - 1)]))
524	{
525	del_msg_element(ntree_p, cmd + 1);
526
527	if (ntree_p->links == 0)
528	{
529	mtree_p->pointers[*cmd & (MAXPTRLEN - 1)] = NULL;
530	mtree_p->links--;
531	xfree(ntree_p);
532	}
533	}
534	}
535	}
536
537	/* msg_tree_parse()
538	*
539	* inputs - Pointer to command to find
540	* - Pointer to MessageTree root
541	* output - Find given command returning Message * if found NULL if not
542	* side effects - none
543	*/
544	static struct Message *
545	msg_tree_parse(const char *cmd)
546	{
547	struct MessageTree *mtree = &msg_tree;
548
549	assert(!EmptyString(cmd));
550
551	while (IsAlpha(cmd) && (mtree = mtree->pointers[cmd & (MAXPTRLEN - 1)]))
552	if (*++cmd == '\0')
553	return mtree->msg;
554
555	return NULL;
556	}
557
558	/* mod_add_cmd()
559	*
560	* inputs - pointer to struct Message
561	* output - none
562	* side effects - load this one command name
563	*/
564	void
565	mod_add_cmd(struct Message *msg)
566	{
567	assert(msg);
568	assert(msg->cmd);
569
570	/* Command already added? */
571	if (msg_tree_parse(msg->cmd) == NULL)
572	add_msg_element(&msg_tree, msg, msg->cmd);
573	}
574
575	/* mod_del_cmd()
576	*
577	* inputs - pointer to struct Message
578	* output - none
579	* side effects - unload this one command name
580	*/
581	void
582	mod_del_cmd(struct Message *msg)
583	{
584	assert(msg);
585	assert(msg->cmd);
586
587	if (msg_tree_parse(msg->cmd))
588	del_msg_element(&msg_tree, msg->cmd);
589	}
590
591	/* find_command()
592	*
593	* inputs - command name
594	* output - pointer to struct Message
595	* side effects - none
596	*/
597	struct Message *
598	find_command(const char *cmd)
599	{
600	return msg_tree_parse(cmd);
601	}
602
603	static void
604	recurse_report_messages(struct Client source_p, const struct MessageTree mtree)
605	{
606	if (mtree->msg)
607	sendto_one_numeric(source_p, &me, RPL_STATSCOMMANDS,
608	mtree->msg->cmd,
609	mtree->msg->count, mtree->msg->bytes,
610	mtree->msg->rcount);
611
612	for (unsigned int i = 0; i < MAXPTRLEN; ++i)
613	if (mtree->pointers[i])
614	recurse_report_messages(source_p, mtree->pointers[i]);
615	}
616
617	/* report_messages()
618	*
619	* inputs - pointer to client to report to
620	* output - NONE
621	* side effects - client is shown list of commands
622	*/
623	void
624	report_messages(struct Client *source_p)
625	{
626	const struct MessageTree *const mtree = &msg_tree;
627
628	for (unsigned int i = 0; i < MAXPTRLEN; ++i)
629	if (mtree->pointers[i])
630	recurse_report_messages(source_p, mtree->pointers[i]);
631	}
632
633	/* m_not_oper()
634	* inputs -
635	* output -
636	* side effects - just returns a nastyogram to given user
637	*/
638	int
639	m_not_oper(struct Client source_p, int parc, char parv[])
640	{
641	sendto_one_numeric(source_p, &me, ERR_NOPRIVILEGES);
642	return 0;
643	}
644
645	int
646	m_unregistered(struct Client source_p, int parc, char parv[])
647	{
648	sendto_one_numeric(source_p, &me, ERR_NOTREGISTERED);
649	return 0;
650	}
651
652	int
653	m_registered(struct Client source_p, int parc, char parv[])
654	{
655	sendto_one_numeric(source_p, &me, ERR_ALREADYREGISTRED);
656	return 0;
657	}
658
659	int
660	m_ignore(struct Client source_p, int parc, char parv[])
661	{
662	return 0;
663	}