trunk/src/parse.c

/*
 *  ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
 *
 *  Copyright (c) 1997-2016 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"


/*
 * (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, get_client_name(client_p, SHOW_IP), lsender);
    sendto_realops_flags(UMODE_DEBUG, L_OPER, SEND_NOTICE,
                         "Unknown prefix (%s) from %s, Squitting %s",
                         lbuffer, get_client_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 || target_p->from == source_p->from) && !chptr)
    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;

  /* 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->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,
                             get_client_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,
                             get_client_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 (1)
    {
       while (*s == ' ')
         *s++ = '\0';

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

       if (*s == ':')
       {
         /* The rest is single parameter--can include blanks also. */
         para[++parc] = s + (!numeric);  /* 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(struct MessageTree));
      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))
    return;

  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))
    return;

  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:	7668
Committed:	Wed Jul 20 17:09:49 2016 UTC (9 years, 1 month ago) by michael
Content type:	text/x-csrc
File size:	18779 byte(s)
Log Message:	- Fixed svn properties
#	Content
1	/*
2	* ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
3	*
4	* Copyright (c) 1997-2016 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
43
44	/*
45	* (based on orabidoo's parser code)
46	*
47	* This has always just been a trie. Look at volume III of Knuth ACP
48	*
49	*
50	* ok, you start out with an array of pointers, each one corresponds
51	* to a letter at the current position in the command being examined.
52	*
53	* so roughly you have this for matching 'trie' or 'tie'
54	*
55	* 't' points -> [MessageTree ] 'r' -> [MessageTree ] -> 'i'
56	* -> [MessageTree ] -> [MessageTree ] -> 'e' and matches
57	*
58	* 'i' -> [MessageTree *] -> 'e' and matches
59	*
60	* BUGS (Limitations!)
61	*
62	* I designed this trie to parse ircd commands. Hence it currently
63	* casefolds. This is trivial to fix by increasing MAXPTRLEN.
64	* This trie also "folds" '{' etc. down. This means, the input to this
65	* trie must be alpha tokens only. This again, is a limitation that
66	* can be overcome by increasing MAXPTRLEN to include upper/lower case
67	* at the expense of more memory. At the extreme end, you could make
68	* MAXPTRLEN 128.
69	*
70	* This is also not a patricia trie. On short ircd tokens, this is
71	* not likely going to matter.
72	*
73	* Diane Bruce (Dianora), June 6 2003
74	*/
75
76	/*
77	* Must be a power of 2, and larger than 26 [a-z]\|[A-Z]. It's used to allocate
78	* the set of pointers at each node of the tree.
79	* There are MAXPTRLEN pointers at each node. Obviously, there have to be more
80	* pointers than ASCII letters. 32 is a nice number since there is then no need
81	* to shift 'A'/'a' to base 0 index, at the expense of a few never used
82	* pointers.
83	* For a small parser like this, this is a good compromise and does
84	* make it somewhat faster. - Dianora
85	*/
86	enum { MAXPTRLEN = 32 };
87
88
89	static struct MessageTree
90	{
91	int links; /* Count of all pointers (including msg) at this node
92	* used as reference count for deletion of _this_ node.
93	*/
94	struct Message *msg;
95	struct MessageTree *pointers[MAXPTRLEN];
96	} msg_tree;
97
98
99	/* remove_unknown()
100	*
101	* inputs -
102	* output -
103	* side effects -
104	*/
105	static void
106	parse_remove_unknown(struct Client client_p, const char lsender, char *lbuffer)
107	{
108	/*
109	* Do kill if it came from a server because it means there is a ghost
110	* user on the other server which needs to be removed. -avalon
111	* Tell opers about this. -Taner
112	*/
113	/*
114	* '[0-9]something' is an ID (KILL/SQUIT depending on its length)
115	* 'nodots' is a nickname (KILL)
116	* 'no.dot.at.start' is a server (SQUIT)
117	*/
118	if ((IsDigit(*lsender) && strlen(lsender) <= IRC_MAXSID) \|\| strchr(lsender, '.'))
119	{
120	sendto_realops_flags(UMODE_DEBUG, L_ADMIN, SEND_NOTICE,
121	"Unknown prefix (%s) from %s, Squitting %s",
122	lbuffer, get_client_name(client_p, SHOW_IP), lsender);
123	sendto_realops_flags(UMODE_DEBUG, L_OPER, SEND_NOTICE,
124	"Unknown prefix (%s) from %s, Squitting %s",
125	lbuffer, get_client_name(client_p, MASK_IP), lsender);
126	sendto_one(client_p, ":%s SQUIT %s :(Unknown prefix (%s) from %s)",
127	me.id, lsender, lbuffer, client_p->name);
128	}
129	else
130	sendto_one(client_p, ":%s KILL %s :%s (Unknown Client)",
131	me.id, lsender, me.name);
132	}
133
134	/*
135	*
136	* parc number of arguments ('sender' counted as one!)
137	* parv[0] pointer to 'sender' (may point to empty string) (not used)
138	* parv[1]..parv[parc-1]
139	* pointers to additional parameters, this is a NULL
140	* terminated list (parv[parc] == NULL).
141	*
142	* WARNING
143	* Numerics are mostly error reports. If there is something
144	* wrong with the message, just DROP it! Don't even think of
145	* sending back a neat error message -- big danger of creating
146	* a ping pong error message...
147	*
148	* Rewritten by Nemesi, Jan 1999, to support numeric nicks in parv[1]
149	*
150	* Called when we get a numeric message from a remote _server_ and we are
151	* supposed to forward it somewhere. Note that we always ignore numerics sent
152	* to 'me' and simply drop the message if we can't handle with this properly:
153	* the savvy approach is NEVER generate an error in response to an... error :)
154	*/
155	static void
156	parse_handle_numeric(unsigned int numeric, struct Client source_p, int parc, char parv[])
157	{
158	struct Client *target_p = NULL;
159	struct Channel *chptr = NULL;
160
161	/*
162	* Avoid trash, we need it to come from a server and have a target
163	*/
164	if (parc < 2 \|\| !IsServer(source_p))
165	return;
166
167	/*
168	* Who should receive this message ? Will we do something with it ?
169	* Note that we use findUser functions, so the target can't be neither
170	* a server, nor a channel (?) nor a list of targets (?) .. u2.10
171	* should never generate numeric replies to non-users anyway
172	* Ahem... it can be a channel actually, csc bots use it :\ --Nem
173	*/
174	if (IsChanPrefix(*parv[1]))
175	chptr = hash_find_channel(parv[1]);
176	else
177	target_p = find_person(source_p, parv[1]);
178
179	if ((!target_p \|\| target_p->from == source_p->from) && !chptr)
180	return;
181
182	/*
183	* Remap low number numerics, not that I understand WHY.. --Nemesi
184	*/
185	/*
186	* Numerics below 100 talk about the current 'connection', you're not
187	* connected to a remote server so it doesn't make sense to send them
188	* remotely - but the information they contain may be useful, so we
189	* remap them up. Weird, but true. -- Isomer
190	*/
191	if (numeric < 100)
192	numeric += 100;
193
194	if (target_p)
195	{
196	/* Fake it for server hiding, if it's our client */
197	if ((ConfigServerHide.hide_servers \|\| IsHidden(source_p)) && MyConnect(target_p) &&
198	!HasUMode(target_p, UMODE_OPER))
199	sendto_one_numeric(target_p, &me, numeric \| SND_EXPLICIT, "%s", parv[2]);
200	else
201	sendto_one_numeric(target_p, source_p, numeric \| SND_EXPLICIT, "%s", parv[2]);
202	}
203	else
204	sendto_channel_butone(source_p, source_p, chptr, 0, "%u %s %s",
205	numeric, chptr->name, parv[2]);
206	}
207
208	/* handle_command()
209	*
210	* inputs - pointer to message block
211	* - pointer to client
212	* - pointer to client message is from
213	* - count of number of args
214	* - pointer to argv[] array
215	* output - -1 if error from server
216	* side effects -
217	*/
218	static void
219	parse_handle_command(struct Message message, struct Client source_p,
220	unsigned int i, char *para[])
221	{
222	if (IsServer(source_p->from))
223	++message->rcount;
224
225	++message->count;
226
227	/* Check right amount of parameters is passed... --is */
228	if (i < message->args_min)
229	sendto_one_numeric(source_p, &me, ERR_NEEDMOREPARAMS, message->cmd);
230	else
231	message->handlers[source_p->from->handler](source_p, i, para);
232	}
233
234	/*
235	* parse a buffer.
236	*
237	* NOTE: parse() should not be called recusively by any other functions!
238	*/
239	void
240	parse(struct Client client_p, char pbuffer, char *bufend)
241	{
242	struct Client *from = client_p;
243	struct Message *message = NULL;
244	char para[MAXPARA + 2]; / <command> + <parameters> + NULL */
245	char *ch = NULL;
246	char *s = NULL;
247	unsigned int numeric = 0;
248	unsigned int parc = 0;
249	unsigned int paramcount;
250
251	if (IsDefunct(client_p))
252	return;
253
254	assert(client_p->connection->fd.flags.open);
255	assert((bufend - pbuffer) < IRCD_BUFSIZE);
256
257	for (ch = pbuffer; ch == ' '; ++ch) / Skip spaces */
258	;
259
260	if (*ch == ':')
261	{
262	/*
263	* Copy the prefix to 'sender' assuming it terminates
264	* with SPACE (or NULL, which is an error, though).
265	*/
266	const char *const sender = ++ch;
267
268	if ((s = strchr(ch, ' ')))
269	{
270	*s = '\0';
271	ch = ++s;
272	}
273
274	if (*sender && IsServer(client_p))
275	{
276	if ((from = hash_find_id(sender)) == NULL)
277	from = hash_find_client(sender);
278
279	/*
280	* Hmm! If the client corresponding to the prefix is not found--what is
281	* the correct action??? Now, I will ignore the message (old IRC just
282	* let it through as if the prefix just wasn't there...) --msa
283	*/
284	if (from == NULL)
285	{
286	++ServerStats.is_unpf;
287	parse_remove_unknown(client_p, sender, pbuffer);
288	return;
289	}
290
291	if (from->from != client_p)
292	{
293	++ServerStats.is_wrdi;
294	sendto_realops_flags(UMODE_DEBUG, L_ADMIN, SEND_NOTICE,
295	"Fake direction: dropped message from %s[%s] via %s",
296	from->name, from->from->name,
297	get_client_name(client_p, SHOW_IP));
298	sendto_realops_flags(UMODE_DEBUG, L_OPER, SEND_NOTICE,
299	"Fake direction: dropped message from %s[%s] via %s",
300	from->name, from->from->name,
301	get_client_name(client_p, MASK_IP));
302	return;
303	}
304	}
305
306	while (*ch == ' ')
307	++ch;
308	}
309
310	if (*ch == '\0')
311	{
312	++ServerStats.is_empt;
313	return;
314	}
315
316	/*
317	* Extract the command code from the packet. Point s to the end
318	* of the command code and calculate the length using pointer
319	* arithmetic. Note: only need length for numerics and all
320	* numerics must have parameters and thus a space after the command
321	* code. -avalon
322	*/
323
324	/* EOB is 3 characters long but is not a numeric */
325	if ((ch + 3) == ' ' && / Ok, let's see if it's a possible numeric */
326	IsDigit(ch) && IsDigit((ch + 1)) && IsDigit(*(ch + 2)))
327	{
328	numeric = (ch - '0') 100 + ((ch + 1) - '0') 10 + (*(ch + 2) - '0');
329	paramcount = 2; /* Destination, and the rest of it */
330	++ServerStats.is_num;
331	s = ch + 3; /* I know this is ' ' from above if */
332	s++ = '\0'; / Blow away the ' ', and point s to next part */
333	}
334	else
335	{
336	if ((s = strchr(ch, ' ')))
337	*s++ = '\0';
338
339	if ((message = find_command(ch)) == NULL)
340	{
341	/*
342	* Note: Give error message only to recognized
343	* persons. It's a nightmare situation to have
344	* two programs sending "Unknown command"'s or
345	* equivalent to each other at full blast....
346	* If it has got to person state, it at least
347	* seems to be well behaving. Perhaps this message
348	* should never be generated, though... --msa
349	* Hm, when is the buffer empty -- if a command
350	* code has been found ?? -Armin
351	*/
352	if (*pbuffer)
353	if (IsClient(from))
354	sendto_one_numeric(from, &me, ERR_UNKNOWNCOMMAND, ch);
355
356	++ServerStats.is_unco;
357	return;
358	}
359
360	assert(message->cmd);
361
362	paramcount = message->args_max;
363
364	size_t length = bufend - ((s) ? s : ch);
365	message->bytes += length;
366	}
367
368	/*
369	* Must the following loop really be so devious? On surface it
370	* splits the message to parameters from blank spaces. But, if
371	* paramcount has been reached, the rest of the message goes into
372	* this last parameter (about same effect as ":" has...) --msa
373	*/
374
375	/* Note initially true: s == NULL \|\| (s - 1) == '\0' !! /
376
377	para[parc] = ch;
378
379	if (message && (message->flags & MFLG_EXTRA))
380	{
381	/*
382	* XXX: This will have to go away after the command handler rewrite
383	*/
384	para[++parc] = message->extra;
385	}
386
387	if (s)
388	{
389	if (paramcount > MAXPARA)
390	paramcount = MAXPARA;
391
392	while (1)
393	{
394	while (*s == ' ')
395	*s++ = '\0';
396
397	if (*s == '\0')
398	break;
399
400	if (*s == ':')
401	{
402	/* The rest is single parameter--can include blanks also. */
403	para[++parc] = s + (!numeric); /* Keep the colon if it's a numeric */
404	break;
405	}
406
407	para[++parc] = s;
408
409	if (parc >= paramcount)
410	break;
411
412	while (s && s != ' ')
413	++s;
414	}
415	}
416
417	para[++parc] = NULL;
418
419	if (message)
420	parse_handle_command(message, from, parc, para);
421	else
422	parse_handle_numeric(numeric, from, parc, para);
423	}
424
425	/* add_msg_element()
426	*
427	* inputs - pointer to MessageTree
428	* - pointer to Message to add for given command
429	* - pointer to current portion of command being added
430	* output - NONE
431	* side effects - recursively build the Message Tree ;-)
432	*/
433	/*
434	* How this works.
435	*
436	* The code first checks to see if its reached the end of the command
437	* If so, that struct MessageTree has a msg pointer updated and the links
438	* count incremented, since a msg pointer is a reference.
439	* Then the code descends recursively, building the trie.
440	* If a pointer index inside the struct MessageTree is NULL a new
441	* child struct MessageTree has to be allocated.
442	* The links (reference count) is incremented as they are created
443	* in the parent.
444	*/
445	static void
446	add_msg_element(struct MessageTree mtree_p, struct Message msg_p,
447	const char *cmd)
448	{
449	struct MessageTree *ntree_p = NULL;
450
451	if (*cmd == '\0')
452	{
453	mtree_p->msg = msg_p;
454	mtree_p->links++; /* Have msg pointer, so up ref count */
455	}
456	else
457	{
458	/*
459	* *cmd & (MAXPTRLEN-1)
460	* convert the char pointed to at *cmd from ASCII to an integer
461	* between 0 and MAXPTRLEN.
462	* Thus 'A' -> 0x1 'B' -> 0x2 'c' -> 0x3 etc.
463	*/
464	if ((ntree_p = mtree_p->pointers[*cmd & (MAXPTRLEN - 1)]) == NULL)
465	{
466	ntree_p = xcalloc(sizeof(struct MessageTree));
467	mtree_p->pointers[*cmd & (MAXPTRLEN - 1)] = ntree_p;
468
469	mtree_p->links++; /* Have new pointer, so up ref count */
470	}
471
472	add_msg_element(ntree_p, msg_p, cmd + 1);
473	}
474	}
475
476	/* del_msg_element()
477	*
478	* inputs - Pointer to MessageTree to delete from
479	* - pointer to command name to delete
480	* output - NONE
481	* side effects - recursively deletes a token from the Message Tree ;-)
482	*/
483	/*
484	* How this works.
485	*
486	* Well, first off, the code recursively descends into the trie
487	* until it finds the terminating letter of the command being removed.
488	* Once it has done that, it marks the msg pointer as NULL then
489	* reduces the reference count on that allocated struct MessageTree
490	* since a command counts as a reference.
491	*
492	* Then it pops up the recurse stack. As it comes back up the recurse
493	* The code checks to see if the child now has no pointers or msg
494	* i.e. the links count has gone to zero. If it's no longer used, the
495	* child struct MessageTree can be deleted. The parent reference
496	* to this child is then removed and the parents link count goes down.
497	* Thus, we continue to go back up removing all unused MessageTree(s)
498	*/
499	static void
500	del_msg_element(struct MessageTree mtree_p, const char cmd)
501	{
502	struct MessageTree *ntree_p = NULL;
503
504	/*
505	* In case this is called for a nonexistent command
506	* check that there is a msg pointer here, else links-- goes -ve
507	* -db
508	*/
509	if (*cmd == '\0' && mtree_p->msg)
510	{
511	mtree_p->msg = NULL;
512	mtree_p->links--;
513	}
514	else
515	{
516	if ((ntree_p = mtree_p->pointers[*cmd & (MAXPTRLEN - 1)]))
517	{
518	del_msg_element(ntree_p, cmd + 1);
519
520	if (ntree_p->links == 0)
521	{
522	mtree_p->pointers[*cmd & (MAXPTRLEN - 1)] = NULL;
523	mtree_p->links--;
524	xfree(ntree_p);
525	}
526	}
527	}
528	}
529
530	/* msg_tree_parse()
531	*
532	* inputs - Pointer to command to find
533	* - Pointer to MessageTree root
534	* output - Find given command returning Message * if found NULL if not
535	* side effects - none
536	*/
537	static struct Message *
538	msg_tree_parse(const char *cmd)
539	{
540	struct MessageTree *mtree = &msg_tree;
541
542	assert(!EmptyString(cmd));
543
544	while (IsAlpha(cmd) && (mtree = mtree->pointers[cmd & (MAXPTRLEN - 1)]))
545	if (*++cmd == '\0')
546	return mtree->msg;
547
548	return NULL;
549	}
550
551	/* mod_add_cmd()
552	*
553	* inputs - pointer to struct Message
554	* output - none
555	* side effects - load this one command name
556	*/
557	void
558	mod_add_cmd(struct Message *msg)
559	{
560	assert(msg);
561	assert(msg->cmd);
562
563	/* Command already added? */
564	if (msg_tree_parse(msg->cmd))
565	return;
566
567	add_msg_element(&msg_tree, msg, msg->cmd);
568	}
569
570	/* mod_del_cmd()
571	*
572	* inputs - pointer to struct Message
573	* output - none
574	* side effects - unload this one command name
575	*/
576	void
577	mod_del_cmd(struct Message *msg)
578	{
579	assert(msg);
580	assert(msg->cmd);
581
582	if (!msg_tree_parse(msg->cmd))
583	return;
584
585	del_msg_element(&msg_tree, msg->cmd);
586	}
587
588	/* find_command()
589	*
590	* inputs - command name
591	* output - pointer to struct Message
592	* side effects - none
593	*/
594	struct Message *
595	find_command(const char *cmd)
596	{
597	return msg_tree_parse(cmd);
598	}
599
600	static void
601	recurse_report_messages(struct Client source_p, const struct MessageTree mtree)
602	{
603	if (mtree->msg)
604	sendto_one_numeric(source_p, &me, RPL_STATSCOMMANDS,
605	mtree->msg->cmd,
606	mtree->msg->count, mtree->msg->bytes,
607	mtree->msg->rcount);
608
609	for (unsigned int i = 0; i < MAXPTRLEN; ++i)
610	if (mtree->pointers[i])
611	recurse_report_messages(source_p, mtree->pointers[i]);
612	}
613
614	/* report_messages()
615	*
616	* inputs - pointer to client to report to
617	* output - NONE
618	* side effects - client is shown list of commands
619	*/
620	void
621	report_messages(struct Client *source_p)
622	{
623	const struct MessageTree *const mtree = &msg_tree;
624
625	for (unsigned int i = 0; i < MAXPTRLEN; ++i)
626	if (mtree->pointers[i])
627	recurse_report_messages(source_p, mtree->pointers[i]);
628	}
629
630	/* m_not_oper()
631	* inputs -
632	* output -
633	* side effects - just returns a nastyogram to given user
634	*/
635	int
636	m_not_oper(struct Client source_p, int parc, char parv[])
637	{
638	sendto_one_numeric(source_p, &me, ERR_NOPRIVILEGES);
639	return 0;
640	}
641
642	int
643	m_unregistered(struct Client source_p, int parc, char parv[])
644	{
645	sendto_one_numeric(source_p, &me, ERR_NOTREGISTERED);
646	return 0;
647	}
648
649	int
650	m_registered(struct Client source_p, int parc, char parv[])
651	{
652	sendto_one_numeric(source_p, &me, ERR_ALREADYREGISTRED);
653	return 0;
654	}
655
656	int
657	m_ignore(struct Client source_p, int parc, char parv[])
658	{
659	return 0;
660	}