ircd/authproc.c: avoid crash on lack of any configured DNSBLs

[solanum.git] / ircd / parse.c

/*
 *  Solanum: a slightly advanced ircd
 *  parse.c: The message parser.
 *
 *  Copyright (C) 1990 Jarkko Oikarinen and University of Oulu, Co Center
 *  Copyright (C) 1996-2002 Hybrid Development Team
 *  Copyright (C) 2002-2005 ircd-ratbox development team
 *  Copyright (C) 2007-2016 Ariadne Conill <ariadne@dereferenced.org>
 *
 *  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., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 *  USA
 */

#include "stdinc.h"
#include "parse.h"
#include "client.h"
#include "channel.h"
#include "hash.h"
#include "match.h"
#include "ircd.h"
#include "numeric.h"
#include "logger.h"
#include "s_stats.h"
#include "send.h"
#include "msg.h"
#include "msgbuf.h"
#include "s_conf.h"
#include "s_serv.h"
#include "packet.h"
#include "s_assert.h"

rb_dictionary *cmd_dict = NULL;
rb_dictionary *alias_dict = NULL;

static void cancel_clients(struct Client *, struct Client *);
static void remove_unknown(struct Client *, const char *, char *);

static void do_numeric(int, struct Client *, struct Client *, int, const char **);

static int handle_command(struct Message *, struct MsgBuf *, struct Client *, struct Client *);

static char buffer[1024];

/* turn a string into a parc/parv pair */

char *reconstruct_parv(int parc, const char *parv[])
{
        static char tmpbuf[BUFSIZE]; int i;

        rb_strlcpy(tmpbuf, parv[0], BUFSIZE);
        for (i = 1; i < parc; i++)
        {
                rb_strlcat(tmpbuf, " ", BUFSIZE);
                rb_strlcat(tmpbuf, parv[i], BUFSIZE);
        }
        return tmpbuf;
}

/* parse()
 *
 * given a raw buffer, parses it and generates parv and parc
 */
void
parse(struct Client *client_p, char *pbuffer, char *bufend)
{
        struct Client *from = client_p;
        char *end;
        int res;
        int numeric = 0;
        struct Message *mptr;
        struct MsgBuf msgbuf;

        s_assert(MyConnect(client_p) &&
                        (client_p->localClient->F != NULL ||
                                client_p->localClient->localflags & LFLAGS_FAKE));
        if(IsAnyDead(client_p))
                return;

        end = bufend - 1;

        /* XXX this should be done before parse() is called */
        if(*end == '\n')
                *end-- = '\0';
        if(*end == '\r')
                *end = '\0';

        res = msgbuf_parse(&msgbuf, pbuffer);
        if (res)
        {
                ServerStats.is_empt++;
                return;
        }

        if (msgbuf.origin != NULL && IsServer(client_p))
        {
                from = find_client(msgbuf.origin);

                /* didnt find any matching client, issue a kill */
                if(from == NULL)
                {
                        ServerStats.is_unpf++;
                        remove_unknown(client_p, msgbuf.origin, pbuffer);
                        return;
                }

                /* fake direction, hmm. */
                if(from->from != client_p)
                {
                        ServerStats.is_wrdi++;
                        cancel_clients(client_p, from);
                        return;
                }
        }

        if(IsDigit(*msgbuf.cmd) && IsDigit(*(msgbuf.cmd + 1)) && IsDigit(*(msgbuf.cmd + 2)))
        {
                mptr = NULL;
                numeric = atoi(msgbuf.cmd);
                ServerStats.is_num++;
        }
        else
        {
                mptr = rb_dictionary_retrieve(cmd_dict, msgbuf.cmd);

                /* no command or its encap only, error */
                if(!mptr || !mptr->cmd)
                {
                        if(IsPerson(from))
                        {
                                sendto_one(from, form_str(ERR_UNKNOWNCOMMAND),
                                           me.name, from->name, msgbuf.cmd);
                        }
                        ServerStats.is_unco++;
                        return;
                }
        }

        if(mptr == NULL)
        {
                do_numeric(numeric, client_p, from, msgbuf.n_para, msgbuf.para);
                return;
        }

        if(handle_command(mptr, &msgbuf, client_p, from) < -1)
        {
                char *p;
                for (p = pbuffer; p <= end; p += 8)
                {
                        /* HACK HACK */
                        /* Its expected this nasty code can be removed
                         * or rewritten later if still needed.
                         */
                        if((p + 8) > end)
                        {
                                for (; p <= end; p++)
                                {
                                        ilog(L_MAIN, "%02x |%c", p[0], p[0]);
                                }
                        }
                        else
                                ilog(L_MAIN,
                                     "%02x %02x %02x %02x %02x %02x %02x %02x |%c%c%c%c%c%c%c%c",
                                     p[0], p[1], p[2], p[3], p[4], p[5],
                                     p[6], p[7], p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]);
                }
        }

}

/*
 * handle_command
 *
 * inputs       - pointer to message block
 *              - pointer to message buffer
 *              - pointer to client
 *              - pointer to client message is from
 * output       - -1 if error from server
 * side effects -
 */
static int
handle_command(struct Message *mptr, struct MsgBuf *msgbuf_p, struct Client *client_p, struct Client *from)
{
        struct MessageEntry ehandler;
        MessageHandler handler = 0;
        char squitreason[80];

        if(IsAnyDead(client_p))
                return -1;

        if(IsServer(client_p))
                mptr->rcount++;

        mptr->count++;

        ehandler = mptr->handlers[from->handler];
        handler = ehandler.handler;

        /* check right amount of params is passed... --is */
        if(msgbuf_p->n_para < ehandler.min_para ||
           (ehandler.min_para && EmptyString(msgbuf_p->para[ehandler.min_para - 1])))
        {
                if(!IsServer(client_p))
                {
                        sendto_one(client_p, form_str(ERR_NEEDMOREPARAMS),
                                   me.name,
                                   EmptyString(client_p->name) ? "*" : client_p->name,
                                   mptr->cmd);
                        if(MyClient(client_p))
                                return (1);
                        else
                                return (-1);
                }

                sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
                                     "Dropping server %s due to (invalid) command '%s'"
                                     " with only %zu arguments (expecting %zu).",
                                     client_p->name, mptr->cmd, msgbuf_p->n_para, ehandler.min_para);
                ilog(L_SERVER,
                     "Insufficient parameters (%zu < %zu) for command '%s' from %s.",
                     msgbuf_p->n_para, ehandler.min_para, mptr->cmd, client_p->name);
                snprintf(squitreason, sizeof squitreason,
                                "Insufficient parameters (%zu < %zu) for command '%s'",
                                msgbuf_p->n_para, ehandler.min_para, mptr->cmd);
                exit_client(client_p, client_p, client_p, squitreason);
                return (-1);
        }

        (*handler) (msgbuf_p, client_p, from, msgbuf_p->n_para, msgbuf_p->para);
        return (1);
}

void
handle_encap(struct MsgBuf *msgbuf_p, struct Client *client_p, struct Client *source_p,
             const char *command, int parc, const char *parv[])
{
        struct Message *mptr;
        struct MessageEntry ehandler;
        MessageHandler handler = 0;

        mptr = rb_dictionary_retrieve(cmd_dict, command);

        if(mptr == NULL || mptr->cmd == NULL)
                return;

        ehandler = mptr->handlers[ENCAP_HANDLER];
        handler = ehandler.handler;

        if((size_t)parc < ehandler.min_para ||
           (ehandler.min_para && EmptyString(parv[ehandler.min_para - 1])))
                return;

        (*handler) (msgbuf_p, client_p, source_p, parc, parv);
}

/*
 * clear_hash_parse()
 *
 * inputs       -
 * output       - NONE
 * side effects - MUST MUST be called at startup ONCE before
 *                any other keyword hash routine is used.
 */
void
clear_hash_parse()
{
        cmd_dict = rb_dictionary_create("command", rb_strcasecmp);
}

/* mod_add_cmd
 *
 * inputs       - command name
 *              - pointer to struct Message
 * output       - none
 * side effects - load this one command name
 *                msg->count msg->bytes is modified in place, in
 *                modules address space. Might not want to do that...
 */
void
mod_add_cmd(struct Message *msg)
{
        s_assert(msg != NULL);
        if(msg == NULL)
                return;

        if (rb_dictionary_find(cmd_dict, msg->cmd) != NULL) {
                ilog(L_MAIN, "Add command: %s already exists", msg->cmd);
                s_assert(0);
                return;
        }

        msg->count = 0;
        msg->rcount = 0;
        msg->bytes = 0;

        rb_dictionary_add(cmd_dict, msg->cmd, msg);
}

/* mod_del_cmd
 *
 * inputs       - command name
 * output       - none
 * side effects - unload this one command name
 */
void
mod_del_cmd(struct Message *msg)
{
        s_assert(msg != NULL);
        if(msg == NULL)
                return;

        if (rb_dictionary_delete(cmd_dict, msg->cmd) == NULL) {
                ilog(L_MAIN, "Delete command: %s not found", msg->cmd);
                s_assert(0);
        }
}

/* cancel_clients()
 *
 * inputs       - client who sent us the message, client with fake
 *                direction
 * outputs      - a given warning about the fake direction
 * side effects -
 */
static void
cancel_clients(struct Client *client_p, struct Client *source_p)
{
        /* ok, fake prefix happens naturally during a burst on a nick
         * collision with TS5, we cant kill them because one client has to
         * survive, so we just send an error.
         */
        if(IsServer(source_p) || IsMe(source_p))
        {
                sendto_realops_snomask(SNO_DEBUG, L_ALL,
                                     "Message for %s[%s] from %s",
                                     source_p->name, source_p->from->name,
                                     client_p->name);
        }
        else
        {
                sendto_realops_snomask(SNO_DEBUG, L_ALL,
                                     "Message for %s[%s@%s!%s] from %s (TS, ignored)",
                                     source_p->name,
                                     source_p->username,
                                     source_p->host,
                                     source_p->from->name,
                                     client_p->name);
        }
}

/* remove_unknown()
 *
 * inputs       - client who gave us message, supposed sender, buffer
 * output       -
 * side effects - kills issued for clients, squits for servers
 */
static void
remove_unknown(struct Client *client_p, const char *lsender, char *lbuffer)
{
        int slen = strlen(lsender);
        char sid[4];
        struct Client *server;

        /* meepfoo      is a nickname (ignore)
         * #XXXXXXXX    is a UID (KILL)
         * #XX          is a SID (SQUIT)
         * meep.foo     is a server (SQUIT)
         */
        if((IsDigit(lsender[0]) && slen == 3) ||
           (strchr(lsender, '.') != NULL))
        {
                sendto_realops_snomask(SNO_DEBUG, L_NETWIDE,
                                     "Unknown prefix (%s) from %s, Squitting %s",
                                     lbuffer, client_p->name, lsender);

                sendto_one(client_p,
                           ":%s SQUIT %s :(Unknown prefix (%s) from %s)",
                           get_id(&me, client_p), lsender,
                           lbuffer, client_p->name);
        }
        else if(!IsDigit(lsender[0]))
                ;
        else if(slen != 9)
                sendto_realops_snomask(SNO_DEBUG, L_NETWIDE,
                                     "Invalid prefix (%s) from %s",
                                     lbuffer, client_p->name);
        else
        {
                memcpy(sid, lsender, 3);
                sid[3] = '\0';
                server = find_server(NULL, sid);
                if (server != NULL && server->from == client_p)
                        sendto_one(client_p, ":%s KILL %s :%s (Unknown Client)",
                                        get_id(&me, client_p), lsender, me.name);
        }
}



/*
 *
 *      parc    number of arguments ('sender' counted as one!)
 *      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...
 */
static void
do_numeric(int numeric, struct Client *client_p, struct Client *source_p, int parc, const char *parv[])
{
        struct Client *target_p;
        struct Channel *chptr;

        if(parc < 2 || !IsServer(source_p))
                return;

        /* Remap low number numerics. */
        if(numeric < 100)
                numeric += 100;

        /*
         * Prepare the parameter portion of the message into 'buffer'.
         * (Because the buffer is twice as large as the message buffer
         * for the socket, no overflow can occur here... ...on current
         * assumptions--bets are off, if these are changed --msa)
         * Note: if buffer is non-empty, it will begin with SPACE.
         */
        if(parc > 1)
        {
                char *t = buffer;       /* Current position within the buffer */
                int i;
                int tl;         /* current length of presently being built string in t */
                for (i = 2; i < (parc - 1); i++)
                {
                        tl = sprintf(t, " %s", parv[i]);
                        t += tl;
                }
                sprintf(t, " :%s", parv[parc - 1]);
        }

        if((target_p = find_client(parv[1])) != NULL)
        {
                if(IsMe(target_p))
                {
                        /*
                         * We shouldn't get numerics sent to us,
                         * any numerics we do get indicate a bug somewhere..
                         */
                        /* ugh.  this is here because of nick collisions.  when two servers
                         * relink, they burst each other their nicks, then perform collides.
                         * if there is a nick collision, BOTH servers will kill their own
                         * nicks, and BOTH will kill the other servers nick, which wont exist,
                         * because it will have been already killed by the local server.
                         *
                         * unfortunately, as we cant guarantee other servers will do the
                         * "right thing" on a nick collision, we have to keep both kills.
                         * ergo we need to ignore ERR_NOSUCHNICK. --fl_
                         */
                        /* quick comment. This _was_ tried. i.e. assume the other servers
                         * will do the "right thing" and kill a nick that is colliding.
                         * unfortunately, it did not work. --Dianora
                         */
                        /* note, now we send PING on server connect, we can
                         * also get ERR_NOSUCHSERVER..
                         */
                        if(numeric != ERR_NOSUCHNICK &&
                           numeric != ERR_NOSUCHSERVER)
                                sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
                                                     "*** %s(via %s) sent a %03d numeric to me: %s",
                                                     source_p->name,
                                                     client_p->name, numeric, buffer);
                        return;
                }
                else if(target_p->from == client_p)
                {
                        /* This message changed direction (nick collision?)
                         * ignore it.
                         */
                        return;
                }

                /* csircd will send out unknown umode flag for +a (admin), drop it here. */
                if(numeric == ERR_UMODEUNKNOWNFLAG && MyClient(target_p))
                        return;

                /* Fake it for server hiding, if its our client */
                sendto_one(target_p, ":%s %03d %s%s",
                           get_id(source_p, target_p), numeric,
                           get_id(target_p, target_p), buffer);
                return;
        }
        else if((chptr = find_channel(parv[1])) != NULL)
                sendto_channel_flags(client_p, ALL_MEMBERS, source_p, chptr,
                                     "%03d %s%s",
                                     numeric, chptr->chname, buffer);
}

void
m_not_oper(struct MsgBuf *msgbuf_p, struct Client *client_p, struct Client *source_p, int parc, const char *parv[])
{
        sendto_one_numeric(source_p, ERR_NOPRIVILEGES, form_str(ERR_NOPRIVILEGES));
}

void
m_unregistered(struct MsgBuf *msgbuf_p, struct Client *client_p, struct Client *source_p, int parc, const char *parv[])
{
        if(IsAnyServer(client_p))
                return;

        /* bit of a hack.
         * I don't =really= want to waste a bit in a flag
         * number_of_nick_changes is only really valid after the client
         * is fully registered..
         */
        if(client_p->localClient->number_of_nick_changes == 0)
        {
                sendto_one(client_p, form_str(ERR_NOTREGISTERED), me.name);
                client_p->localClient->number_of_nick_changes++;
        }
}

void
m_registered(struct MsgBuf *msgbuf_p, struct Client *client_p, struct Client *source_p, int parc, const char *parv[])
{
        sendto_one(client_p, form_str(ERR_ALREADYREGISTRED), me.name, source_p->name);
}

void
m_ignore(struct MsgBuf *msgbuf_p, struct Client *client_p, struct Client *source_p, int parc, const char *parv[])
{
        /* Does nothing */
}