m_server: reenable required cap negotiation

[solanum.git] / modules / core / m_server.c

/*
 *  ircd-ratbox: A slightly useful ircd.
 *  m_server.c: Introduces a server.
 *
 *  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
 *
 *  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
 *
 *  $Id: m_server.c 3291 2007-03-28 14:30:10Z jilles $
 */

#include "stdinc.h"
#include "client.h"             /* client struct */
#include "common.h"             /* TRUE bleah */
#include "hash.h"               /* add_to_client_hash */
#include "match.h"
#include "ircd.h"               /* me */
#include "numeric.h"            /* ERR_xxx */
#include "s_conf.h"             /* struct ConfItem */
#include "s_newconf.h"
#include "logger.h"             /* log level defines */
#include "s_serv.h"             /* server_estab, check_server */
#include "s_stats.h"            /* ServerStats */
#include "scache.h"
#include "send.h"               /* sendto_one */
#include "msg.h"
#include "parse.h"
#include "modules.h"

static int mr_server(struct Client *, struct Client *, int, const char **);
static int ms_server(struct Client *, struct Client *, int, const char **);
static int ms_sid(struct Client *, struct Client *, int, const char **);

struct Message server_msgtab = {
        "SERVER", 0, 0, 0, MFLG_SLOW | MFLG_UNREG,
        {{mr_server, 4}, mg_reg, mg_ignore, {ms_server, 4}, mg_ignore, mg_reg}
};
struct Message sid_msgtab = {
        "SID", 0, 0, 0, MFLG_SLOW,
        {mg_ignore, mg_reg, mg_ignore, {ms_sid, 5}, mg_ignore, mg_reg}
};

mapi_clist_av1 server_clist[] = { &server_msgtab, &sid_msgtab, NULL };

DECLARE_MODULE_AV1(server, NULL, NULL, server_clist, NULL, NULL, "$Revision: 3291 $");

int bogus_host(const char *host);
static int set_server_gecos(struct Client *, const char *);

/*
 * mr_server - SERVER message handler
 *      parv[1] = servername
 *      parv[2] = serverinfo/hopcount
 *      parv[3] = serverinfo
 */
static int
mr_server(struct Client *client_p, struct Client *source_p, int parc, const char *parv[])
{
        char info[REALLEN + 1];
        const char *name;
        struct Client *target_p;
        int hop;
        unsigned int required_mask;

        name = parv[1];
        hop = atoi(parv[2]);
        rb_strlcpy(info, parv[3], sizeof(info));

        if (IsHandshake(client_p) && irccmp(client_p->name, name))
        {
                sendto_realops_snomask(SNO_GENERAL, is_remote_connect(client_p) ? L_NETWIDE : L_ALL,
                                "Server %s has unexpected name %s",
                                client_p->name, name);
                ilog(L_SERVER, "Server %s has unexpected name %s",
                                log_client_name(client_p, SHOW_IP), name);
                exit_client(client_p, client_p, client_p, "Server name mismatch");
                return 0;
        }

        /* 
         * Reject a direct nonTS server connection if we're TS_ONLY -orabidoo
         */
        if(!DoesTS(client_p))
        {
                sendto_realops_snomask(SNO_GENERAL, L_ALL, "Link %s dropped, non-TS server",
                                     client_p->name);
                exit_client(client_p, client_p, client_p, "Non-TS server");
                return 0;
        }

        if(bogus_host(name))
        {
                exit_client(client_p, client_p, client_p, "Bogus server name");
                return 0;
        }

        /* check to ensure any "required" caps are set. --nenolod */
        /* XXX: show required CAPABs. */
        required_mask = capability_index_get_required(serv_capindex);
        if (!(client_p->localClient->caps & required_mask))
        {
                exit_client(client_p, client_p, client_p, "Missing required CAPABs");

                return 0;
        }

        /* Now we just have to call check_server and everything should be
         * check for us... -A1kmm. */
        switch (check_server(name, client_p))
        {
        case -1:
                if(ConfigFileEntry.warn_no_nline)
                {
                        sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                             "Unauthorised server connection attempt from %s: "
                                             "No entry for servername %s",
                                             "[@255.255.255.255]", name);

                        ilog(L_SERVER, "Access denied, no connect block for server %s%s",
                             EmptyString(client_p->name) ? name : "",
                             log_client_name(client_p, SHOW_IP));
                }

                exit_client(client_p, client_p, client_p, "Invalid servername.");
                return 0;
                /* NOT REACHED */
                break;

        case -2:
                sendto_realops_snomask(SNO_GENERAL, is_remote_connect(client_p) ? L_NETWIDE : L_ALL,
                                     "Unauthorised server connection attempt from %s: "
                                     "Bad credentials for server %s",
                                     "[@255.255.255.255]", name);

                ilog(L_SERVER, "Access denied, invalid credentials for server %s%s",
                     EmptyString(client_p->name) ? name : "",
                     log_client_name(client_p, SHOW_IP));

                exit_client(client_p, client_p, client_p, "Invalid credentials.");
                return 0;
                /* NOT REACHED */
                break;

        case -3:
                sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                     "Unauthorised server connection attempt from %s: "
                                     "Invalid host for server %s",
                                     "[@255.255.255.255]", name);

                ilog(L_SERVER, "Access denied, invalid host for server %s%s",
                     EmptyString(client_p->name) ? name : "",
                     log_client_name(client_p, SHOW_IP));

                exit_client(client_p, client_p, client_p, "Invalid host.");
                return 0;
                /* NOT REACHED */
                break;

                /* servername is > HOSTLEN */
        case -4:
                sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                     "Invalid servername %s from %s",
                                     name, "[@255.255.255.255]");
                ilog(L_SERVER, "Access denied, invalid servername from %s",
                     log_client_name(client_p, SHOW_IP));

                exit_client(client_p, client_p, client_p, "Invalid servername.");
                return 0;
                /* NOT REACHED */
                break;
        case -5:
                sendto_realops_snomask(SNO_GENERAL, L_ALL,
                     "Connection from servername %s requires SSL/TLS but is plaintext",
                     name);
                ilog(L_SERVER, "Access denied, requires SSL/TLS but is plaintext from %s", 
                     log_client_name(client_p, SHOW_IP));

                exit_client(client_p, client_p, client_p, "Access denied, requires SSL/TLS but is plaintext");
                return 0;
        }

        /* require TS6 for direct links */
        if(!IsCapable(client_p, CAP_TS6))
        {
                sendto_realops_snomask(SNO_GENERAL, is_remote_connect(client_p) ? L_NETWIDE : L_ALL,
                                        "Link %s dropped, TS6 protocol is required", name);
                exit_client(client_p, client_p, client_p, "Incompatible TS version");
                return 0;
        }

        if((target_p = find_server(NULL, name)))
        {
                /*
                 * This link is trying feed me a server that I already have
                 * access through another path -- multiple paths not accepted
                 * currently, kill this link immediately!!
                 *
                 * Rather than KILL the link which introduced it, KILL the
                 * youngest of the two links. -avalon
                 *
                 * Definitely don't do that here. This is from an unregistered
                 * connect - A1kmm.
                 */
                if (target_p->servptr->flags & FLAGS_SERVICE)
                {
                        /* Assume any servers introduced by services
                         * are jupes.
                         * -- jilles
                         */
                        sendto_one(client_p, "ERROR :Server juped.");
                }
                else
                {
                        sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                             "Attempt to re-introduce server %s from %s",
                                             name, "[@255.255.255.255]");
                        ilog(L_SERVER, "Attempt to re-introduce server %s from %s",
                                        name, log_client_name(client_p, SHOW_IP));

                        sendto_one(client_p, "ERROR :Server already exists.");
                }
                exit_client(client_p, client_p, client_p, "Server Exists");
                return 0;
        }

        if(has_id(client_p) && (target_p = find_id(client_p->id)) != NULL)
        {
                sendto_realops_snomask(SNO_GENERAL, is_remote_connect(client_p) ? L_NETWIDE : L_ALL,
                                     "Attempt to re-introduce SID %s from %s%s (already in use by %s)",
                                     client_p->id,
                                     EmptyString(client_p->name) ? name : "",
                                     client_p->name, target_p->name);
                ilog(L_SERVER, "Attempt to re-introduce SID %s from %s%s (already in use by %s)",
                                client_p->id,
                                EmptyString(client_p->name) ? name : "",
                                log_client_name(client_p, SHOW_IP),
                                target_p->name);

                sendto_one(client_p, "ERROR :SID already exists.");
                exit_client(client_p, client_p, client_p, "SID Exists");
                return 0;
        }

        /*
         * if we are connecting (Handshake), we already have the name from the
         * C:line in client_p->name
         */

        rb_strlcpy(client_p->name, name, sizeof(client_p->name));
        set_server_gecos(client_p, info);
        client_p->hopcount = hop;
        server_estab(client_p);

        return 0;
}

/*
 * ms_server - SERVER message handler
 *      parv[1] = servername
 *      parv[2] = serverinfo/hopcount
 *      parv[3] = serverinfo
 */
static int
ms_server(struct Client *client_p, struct Client *source_p, int parc, const char *parv[])
{
        char info[REALLEN + 1];
        /* same size as in s_misc.c */
        const char *name;
        struct Client *target_p;
        struct remote_conf *hub_p;
        hook_data_client hdata;
        int hop;
        int hlined = 0;
        int llined = 0;
        rb_dlink_node *ptr;
        char squitreason[160];

        name = parv[1];
        hop = atoi(parv[2]);
        rb_strlcpy(info, parv[3], sizeof(info));

        if((target_p = find_server(NULL, name)))
        {
                /*
                 * This link is trying feed me a server that I already have
                 * access through another path -- multiple paths not accepted
                 * currently, kill this link immediately!!
                 *
                 * Rather than KILL the link which introduced it, KILL the
                 * youngest of the two links. -avalon
                 *
                 * I think that we should exit the link itself, not the introducer,
                 * and we should always exit the most recently received(i.e. the
                 * one we are receiving this SERVER for. -A1kmm
                 *
                 * You *cant* do this, if you link somewhere, it bursts you a server
                 * that already exists, then sends you a client burst, you squit the
                 * server, but you keep getting the burst of clients on a server that
                 * doesnt exist, although ircd can handle it, its not a realistic
                 * solution.. --fl_ 
                 */
                ilog(L_SERVER, "Link %s cancelled, server %s already exists",
                        client_p->name, name);

                rb_snprintf(squitreason, sizeof squitreason,
                                "Server %s already exists",
                                name);
                exit_client(client_p, client_p, &me, squitreason);
                return 0;
        }

        /* 
         * User nicks never have '.' in them and server names
         * must always have '.' in them.
         */
        if(strchr(name, '.') == NULL)
        {
                /*
                 * Server trying to use the same name as a person. Would
                 * cause a fair bit of confusion. Enough to make it hellish
                 * for a while and servers to send stuff to the wrong place.
                 */
                sendto_one(client_p, "ERROR :Nickname %s already exists!", name);
                sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                     "Link %s cancelled: Server/nick collision on %s",
                                     client_p->name, name);
                ilog(L_SERVER, "Link %s cancelled: Server/nick collision on %s",
                        client_p->name, name);

                exit_client(client_p, client_p, client_p, "Nick as Server");
                return 0;
        }

        /*
         * Server is informing about a new server behind
         * this link. Create REMOTE server structure,
         * add it to list and propagate word to my other
         * server links...
         */

        /*
         * See if the newly found server is behind a guaranteed
         * leaf. If so, close the link.
         *
         */
        RB_DLINK_FOREACH(ptr, hubleaf_conf_list.head)
        {
                hub_p = ptr->data;

                if(match(hub_p->server, client_p->name) && match(hub_p->host, name))
                {
                        if(hub_p->flags & CONF_HUB)
                                hlined++;
                        else
                                llined++;
                }
        }

        /* Ok, this way this works is
         *
         * A server can have a CONF_HUB allowing it to introduce servers
         * behind it.
         *
         * connect {
         *            name = "irc.bighub.net";
         *            hub_mask="*";
         *            ...
         * 
         * That would allow "irc.bighub.net" to introduce anything it wanted..
         *
         * However
         *
         * connect {
         *            name = "irc.somehub.fi";
         *            hub_mask="*";
         *            leaf_mask="*.edu";
         *...
         * Would allow this server in finland to hub anything but
         * .edu's
         */

        /* Ok, check client_p can hub the new server */
        if(!hlined)
        {
                /* OOOPs nope can't HUB */
                sendto_realops_snomask(SNO_GENERAL, L_ALL, "Non-Hub link %s introduced %s.",
                                     client_p->name, name);
                ilog(L_SERVER, "Non-Hub link %s introduced %s.",
                        client_p->name, name);

                rb_snprintf(squitreason, sizeof squitreason,
                                "No matching hub_mask for %s",
                                name);
                exit_client(NULL, client_p, &me, squitreason);
                return 0;
        }

        /* Check for the new server being leafed behind this HUB */
        if(llined)
        {
                /* OOOPs nope can't HUB this leaf */
                sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                     "Link %s introduced leafed server %s.",
                                     client_p->name, name);
                ilog(L_SERVER, "Link %s introduced leafed server %s.",
                        client_p->name, name);  

                rb_snprintf(squitreason, sizeof squitreason,
                                "Matching leaf_mask for %s",
                                name);
                exit_client(NULL, client_p, &me, squitreason);
                return 0;
        }



        if(strlen(name) > HOSTLEN)
        {
                sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                     "Link %s introduced server with invalid servername %s",
                                     client_p->name, name);
                ilog(L_SERVER, "Link %s introduced server with invalid servername %s",
                        client_p->name, name);

                exit_client(NULL, client_p, &me, "Invalid servername introduced.");
                return 0;
        }

        target_p = make_client(client_p);
        make_server(target_p);
        target_p->hopcount = hop;

        rb_strlcpy(target_p->name, name, sizeof(target_p->name));

        set_server_gecos(target_p, info);

        target_p->servptr = source_p;

        SetServer(target_p);

        rb_dlinkAddTail(target_p, &target_p->node, &global_client_list);
        rb_dlinkAddTailAlloc(target_p, &global_serv_list);
        add_to_client_hash(target_p->name, target_p);
        rb_dlinkAdd(target_p, &target_p->lnode, &target_p->servptr->serv->servers);

        target_p->serv->nameinfo = scache_connect(target_p->name, target_p->info, IsHidden(target_p));

        sendto_server(client_p, NULL, NOCAPS, NOCAPS,
                      ":%s SERVER %s %d :%s%s",
                      source_p->name, target_p->name, target_p->hopcount + 1,
                      IsHidden(target_p) ? "(H) " : "", target_p->info);

        sendto_realops_snomask(SNO_EXTERNAL, L_ALL,
                             "Server %s being introduced by %s", target_p->name, source_p->name);

        /* quick, dirty EOB.  you know you love it. */
        sendto_one(target_p, ":%s PING %s %s", get_id(&me, target_p), me.name, target_p->name);

        hdata.client = source_p;
        hdata.target = target_p;
        call_hook(h_server_introduced, &hdata);

        return 0;
}

static int
ms_sid(struct Client *client_p, struct Client *source_p, int parc, const char *parv[])
{
        struct Client *target_p;
        struct remote_conf *hub_p;
        hook_data_client hdata;
        rb_dlink_node *ptr;
        int hop;
        int hlined = 0;
        int llined = 0;
        char squitreason[160];

        hop = atoi(parv[2]);

        /* collision on the name? */
        if((target_p = find_server(NULL, parv[1])) != NULL)
        {
                ilog(L_SERVER, "Link %s cancelled, server %s already exists",
                        client_p->name, parv[1]);

                rb_snprintf(squitreason, sizeof squitreason,
                                "Server %s already exists",
                                parv[1]);
                exit_client(NULL, client_p, &me, squitreason);
                return 0;
        }

        /* collision on the SID? */
        if((target_p = find_id(parv[3])) != NULL)
        {
                sendto_wallops_flags(UMODE_WALLOP, &me,
                                     "Link %s cancelled, SID %s for server %s already in use by %s",
                                     client_p->name, parv[3], parv[1], target_p->name);
                sendto_server(NULL, NULL, CAP_TS6, NOCAPS,
                                     ":%s WALLOPS :Link %s cancelled, SID %s for server %s already in use by %s",
                                     me.id, client_p->name, parv[3], parv[1], target_p->name);
                ilog(L_SERVER, "Link %s cancelled, SID %s for server %s already in use by %s",
                        client_p->name, parv[3], parv[1], target_p->name);

                rb_snprintf(squitreason, sizeof squitreason,
                                "SID %s for %s already in use by %s",
                                parv[3], parv[1], target_p->name);
                exit_client(NULL, client_p, &me, squitreason);
                return 0;
        }

        if(bogus_host(parv[1]) || strlen(parv[1]) > HOSTLEN)
        {
                sendto_one(client_p, "ERROR :Invalid servername");
                sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                     "Link %s cancelled, servername %s invalid",
                                     client_p->name, parv[1]);
                ilog(L_SERVER, "Link %s cancelled, servername %s invalid",
                        client_p->name, parv[1]);

                exit_client(NULL, client_p, &me, "Bogus server name");
                return 0;
        }

        if(!IsDigit(parv[3][0]) || !IsIdChar(parv[3][1]) ||
           !IsIdChar(parv[3][2]) || parv[3][3] != '\0')
        {
                sendto_one(client_p, "ERROR :Invalid SID");
                sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                     "Link %s cancelled, SID %s invalid",
                                     client_p->name, parv[3]);
                ilog(L_SERVER, "Link %s cancelled, SID %s invalid",
                        client_p->name, parv[3]);

                exit_client(NULL, client_p, &me, "Bogus SID");
                return 0;
        }

        /* for the directly connected server:
         * H: allows it to introduce a server matching that mask
         * L: disallows it introducing a server matching that mask
         */
        RB_DLINK_FOREACH(ptr, hubleaf_conf_list.head)
        {
                hub_p = ptr->data;

                if(match(hub_p->server, client_p->name) && match(hub_p->host, parv[1]))
                {
                        if(hub_p->flags & CONF_HUB)
                                hlined++;
                        else
                                llined++;
                }
        }

        /* no matching hub_mask */
        if(!hlined)
        {
                sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                     "Non-Hub link %s introduced %s.",
                                     client_p->name, parv[1]);
                ilog(L_SERVER, "Non-Hub link %s introduced %s.",
                        client_p->name, parv[1]);

                rb_snprintf(squitreason, sizeof squitreason,
                                "No matching hub_mask for %s",
                                parv[1]);
                exit_client(NULL, client_p, &me, squitreason);
                return 0;
        }

        /* matching leaf_mask */
        if(llined)
        {
                sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                     "Link %s introduced leafed server %s.",
                                     client_p->name, parv[1]);
                ilog(L_SERVER, "Link %s introduced leafed server %s.",
                        client_p->name, parv[1]);       

                rb_snprintf(squitreason, sizeof squitreason,
                                "Matching leaf_mask for %s",
                                parv[1]);
                exit_client(NULL, client_p, &me, squitreason);
                return 0;
        }

        /* ok, alls good */
        target_p = make_client(client_p);
        make_server(target_p);

        rb_strlcpy(target_p->name, parv[1], sizeof(target_p->name));
        target_p->hopcount = atoi(parv[2]);
        strcpy(target_p->id, parv[3]);
        set_server_gecos(target_p, parv[4]);

        target_p->servptr = source_p;
        SetServer(target_p);

        rb_dlinkAddTail(target_p, &target_p->node, &global_client_list);
        rb_dlinkAddTailAlloc(target_p, &global_serv_list);
        add_to_client_hash(target_p->name, target_p);
        add_to_id_hash(target_p->id, target_p);
        rb_dlinkAdd(target_p, &target_p->lnode, &target_p->servptr->serv->servers);

        target_p->serv->nameinfo = scache_connect(target_p->name, target_p->info, IsHidden(target_p));

        sendto_server(client_p, NULL, CAP_TS6, NOCAPS,
                      ":%s SID %s %d %s :%s%s",
                      source_p->id, target_p->name, target_p->hopcount + 1,
                      target_p->id, IsHidden(target_p) ? "(H) " : "", target_p->info);

        sendto_realops_snomask(SNO_EXTERNAL, L_ALL,
                             "Server %s being introduced by %s", target_p->name, source_p->name);

        /* quick, dirty EOB.  you know you love it. */
        sendto_one(target_p, ":%s PING %s %s",
                   get_id(&me, target_p), me.name, get_id(target_p, target_p));

        hdata.client = source_p;
        hdata.target = target_p;
        call_hook(h_server_introduced, &hdata);

        return 0;
}

/* set_server_gecos()
 *
 * input        - pointer to client
 * output       - none
 * side effects - servers gecos field is set
 */
static int
set_server_gecos(struct Client *client_p, const char *info)
{
        /* check the info for [IP] */
        if(info[0])
        {
                char *p;
                char *s;

                s = LOCAL_COPY(info);

                /* we should only check the first word for an ip */
                if((p = strchr(s, ' ')))
                        *p = '\0';

                /* check for a ] which would symbolise an [IP] */
                if(strchr(s, ']'))
                {
                        /* set s to after the first space */
                        if(p)
                                s = ++p;
                        else
                                s = NULL;
                }
                /* no ], put the space back */
                else if(p)
                        *p = ' ';

                /* p may have been set to a trailing space, so check s exists and that
                 * it isnt \0 */
                if(s && (*s != '\0'))
                {
                        /* a space? if not (H) could be the last part of info.. */
                        if((p = strchr(s, ' ')))
                                *p = '\0';

                        /* check for (H) which is a hidden server */
                        if(!strcmp(s, "(H)"))
                        {
                                SetHidden(client_p);

                                /* if there was no space.. theres nothing to set info to */
                                if(p)
                                        s = ++p;
                                else
                                        s = NULL;
                        }
                        else if(p)
                                *p = ' ';

                        /* if there was a trailing space, s could point to \0, so check */
                        if(s && (*s != '\0'))
                        {
                                rb_strlcpy(client_p->info, s, sizeof(client_p->info));
                                return 1;
                        }
                }
        }

        rb_strlcpy(client_p->info, "(Unknown Location)", sizeof(client_p->info));

        return 1;
}

/*
 * bogus_host
 *
 * inputs       - hostname
 * output       - 1 if a bogus hostname input, 0 if its valid
 * side effects - none
 */
int
bogus_host(const char *host)
{
        int bogus_server = 0;
        const char *s;
        int dots = 0;

        for(s = host; *s; s++)
        {
                if(!IsServChar(*s))
                {
                        bogus_server = 1;
                        break;
                }
                if('.' == *s)
                        ++dots;
        }

        if(!dots || bogus_server)
                return 1;

        return 0;
}