/*
 *  ircd-ratbox: A slightly useful ircd.
 *  listener.c: Listens on a port.
 *
 *  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
 *
 */

#include "stdinc.h"
#include "setup.h"
#include "listener.h"
#include "client.h"
#include "match.h"
#include "ircd.h"
#include "ircd_defs.h"
#include "numeric.h"
#include "s_conf.h"
#include "s_newconf.h"
#include "s_stats.h"
#include "send.h"
#include "s_auth.h"
#include "reject.h"
#include "s_conf.h"
#include "hostmask.h"
#include "sslproc.h"
#include "hash.h"

#ifndef INADDR_NONE
#define INADDR_NONE ((unsigned int) 0xffffffff)
#endif

#if defined(NO_IN6ADDR_ANY) && defined(RB_IPV6)
static const struct in6_addr in6addr_any =
{ { { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 } } };
#endif

static struct Listener *ListenerPollList = NULL;
static int accept_precallback(rb_fde_t *F, struct sockaddr *addr, rb_socklen_t addrlen, void *data);
static void accept_callback(rb_fde_t *F, int status, struct sockaddr *addr, rb_socklen_t addrlen, void *data);

static struct Listener *
make_listener(struct rb_sockaddr_storage *addr)
{
    struct Listener *listener = (struct Listener *) rb_malloc(sizeof(struct Listener));
    s_assert(0 != listener);
    listener->name = me.name;
    listener->F = NULL;

    memcpy(&listener->addr, addr, sizeof(struct rb_sockaddr_storage));
    listener->next = NULL;
    return listener;
}

void
free_listener(struct Listener *listener)
{
    s_assert(NULL != listener);
    if(listener == NULL)
        return;
    /*
     * remove from listener list
     */
    if(listener == ListenerPollList)
        ListenerPollList = listener->next;
    else {
        struct Listener *prev = ListenerPollList;
        for (; prev; prev = prev->next) {
            if(listener == prev->next) {
                prev->next = listener->next;
                break;
            }
        }
    }

    /* free */
    rb_free(listener);
}

#define PORTNAMELEN 6		/* ":31337" */

/*
 * get_listener_name - return displayable listener name and port
 * returns "host.foo.org:6667" for a given listener
 */
const char *
get_listener_name(const struct Listener *listener)
{
    static char buf[HOSTLEN + HOSTLEN + PORTNAMELEN + 4];
    int port = 0;

    s_assert(NULL != listener);
    if(listener == NULL)
        return NULL;

#ifdef RB_IPV6
    if(listener->addr.ss_family == AF_INET6)
        port = ntohs(((const struct sockaddr_in6 *)&listener->addr)->sin6_port);
    else
#endif
        port = ntohs(((const struct sockaddr_in *)&listener->addr)->sin_port);

    snprintf(buf, sizeof(buf), "%s[%s/%u]", me.name, listener->name, port);
    return buf;
}

/*
 * show_ports - send port listing to a client
 * inputs       - pointer to client to show ports to
 * output       - none
 * side effects - show ports
 */
void
show_ports(struct Client *source_p)
{
    struct Listener *listener = 0;

    for (listener = ListenerPollList; listener; listener = listener->next) {
        sendto_one_numeric(source_p, RPL_STATSPLINE,
                           form_str(RPL_STATSPLINE), 'P',
#ifdef RB_IPV6
                           ntohs(listener->addr.ss_family == AF_INET ? ((struct sockaddr_in *)&listener->addr)->sin_port :
                                 ((struct sockaddr_in6 *)&listener->addr)->sin6_port),
#else
                           ntohs(((struct sockaddr_in *)&listener->addr)->sin_port),
#endif
                           IsOperAdmin(source_p) ? listener->name : me.name,
                           listener->ref_count, (listener->active) ? "active" : "disabled",
                           listener->ssl ? " ssl" : "");
    }
}

/*
 * inetport - create a listener socket in the AF_INET or AF_INET6 domain,
 * bind it to the port given in 'port' and listen to it
 * returns true (1) if successful false (0) on error.
 *
 * If the operating system has a define for SOMAXCONN, use it, otherwise
 * use RATBOX_SOMAXCONN
 */
#ifdef SOMAXCONN
#undef RATBOX_SOMAXCONN
#define RATBOX_SOMAXCONN SOMAXCONN
#endif

static int
inetport(struct Listener *listener)
{
    rb_fde_t *F;
    int opt = 1;

    /*
     * At first, open a new socket
     */

    F = rb_socket(GET_SS_FAMILY(&listener->addr), SOCK_STREAM, 0, "Listener socket");

#ifdef RB_IPV6
    if(listener->addr.ss_family == AF_INET6) {
        struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)&listener->addr;
        if(!IN6_ARE_ADDR_EQUAL(&in6->sin6_addr, &in6addr_any)) {
            rb_inet_ntop(AF_INET6, &in6->sin6_addr, listener->vhost, sizeof(listener->vhost));
            listener->name = listener->vhost;
        }
    } else
#endif
    {
        struct sockaddr_in *in = (struct sockaddr_in *)&listener->addr;
        if(in->sin_addr.s_addr != INADDR_ANY) {
            rb_inet_ntop(AF_INET, &in->sin_addr, listener->vhost, sizeof(listener->vhost));
            listener->name = listener->vhost;
        }
    }

    if(F == NULL) {
        ilog_error("opening listener socket");
        return 0;
    } else if((maxconnections - 10) < rb_get_fd(F)) { /* XXX this is kinda bogus*/
        ilog_error("no more connections left for listener");
        rb_close(F);
        return 0;
    }

    /*
     * XXX - we don't want to do all this crap for a listener
     * set_sock_opts(listener);
     */
    if(setsockopt(rb_get_fd(F), SOL_SOCKET, SO_REUSEADDR, (char *) &opt, sizeof(opt))) {
        ilog_error("setting SO_REUSEADDR for listener");
        rb_close(F);
        return 0;
    }

    /*
     * Bind a port to listen for new connections if port is non-null,
     * else assume it is already open and try get something from it.
     */

    if(bind(rb_get_fd(F), (struct sockaddr *) &listener->addr, GET_SS_LEN(&listener->addr))) {
        ilog_error("binding listener socket");
        rb_close(F);
        return 0;
    }

    if(rb_listen(F, RATBOX_SOMAXCONN, listener->defer_accept)) {
        ilog_error("listen()");
        rb_close(F);
        return 0;
    }

    listener->F = F;

    rb_accept_tcp(listener->F, accept_precallback, accept_callback, listener);
    return 1;
}

static struct Listener *
find_listener(struct rb_sockaddr_storage *addr)
{
    struct Listener *listener = NULL;
    struct Listener *last_closed = NULL;

    for (listener = ListenerPollList; listener; listener = listener->next) {
        if(addr->ss_family != listener->addr.ss_family)
            continue;

        switch(addr->ss_family) {
        case AF_INET: {
            struct sockaddr_in *in4 = (struct sockaddr_in *)addr;
            struct sockaddr_in *lin4 = (struct sockaddr_in *)&listener->addr;
            if(in4->sin_addr.s_addr == lin4->sin_addr.s_addr &&
               in4->sin_port == lin4->sin_port ) {
                if(listener->F == NULL)
                    last_closed = listener;
                else
                    return(listener);
            }
            break;
        }
#ifdef RB_IPV6
        case AF_INET6: {
            struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)addr;
            struct sockaddr_in6 *lin6 =(struct sockaddr_in6 *)&listener->addr;
            if(IN6_ARE_ADDR_EQUAL(&in6->sin6_addr, &lin6->sin6_addr) &&
               in6->sin6_port == lin6->sin6_port) {
                if(listener->F == NULL)
                    last_closed = listener;
                else
                    return(listener);
            }
            break;

        }
#endif

        default:
            break;
        }
    }
    return last_closed;
}


/*
 * add_listener- create a new listener
 * port - the port number to listen on
 * vhost_ip - if non-null must contain a valid IP address string in
 * the format "255.255.255.255"
 */
void
add_listener(int port, const char *vhost_ip, int family, int ssl, int defer_accept)
{
    struct Listener *listener;
    struct rb_sockaddr_storage vaddr;

    /*
     * if no port in conf line, don't bother
     */
    if(port == 0)
        return;
    memset(&vaddr, 0, sizeof(vaddr));
    vaddr.ss_family = family;

    if(vhost_ip != NULL) {
        if(family == AF_INET) {
            if(rb_inet_pton(family, vhost_ip, &((struct sockaddr_in *)&vaddr)->sin_addr) <= 0)
                return;
        }
#ifdef RB_IPV6
        else {
            if(rb_inet_pton(family, vhost_ip, &((struct sockaddr_in6 *)&vaddr)->sin6_addr) <= 0)
                return;

        }
#endif
    } else {
        switch(family) {
        case AF_INET:
            ((struct sockaddr_in *)&vaddr)->sin_addr.s_addr = INADDR_ANY;
            break;
#ifdef RB_IPV6
        case AF_INET6:
            memcpy(&((struct sockaddr_in6 *)&vaddr)->sin6_addr, &in6addr_any, sizeof(struct in6_addr));
            break;
        default:
            return;
#endif
        }
    }
    switch(family) {
    case AF_INET:
        SET_SS_LEN(&vaddr, sizeof(struct sockaddr_in));
        ((struct sockaddr_in *)&vaddr)->sin_port = htons(port);
        break;
#ifdef RB_IPV6
    case AF_INET6:
        SET_SS_LEN(&vaddr, sizeof(struct sockaddr_in6));
        ((struct sockaddr_in6 *)&vaddr)->sin6_port = htons(port);
        break;
#endif
    default:
        break;
    }
    if((listener = find_listener(&vaddr))) {
        if(listener->F != NULL)
            return;
    } else {
        listener = make_listener(&vaddr);
        listener->next = ListenerPollList;
        ListenerPollList = listener;
    }

    listener->F = NULL;
    listener->ssl = ssl;
    listener->defer_accept = defer_accept;

    if(inetport(listener))
        listener->active = 1;
    else
        close_listener(listener);
}

/*
 * close_listener - close a single listener
 */
void
close_listener(struct Listener *listener)
{
    s_assert(listener != NULL);
    if(listener == NULL)
        return;
    if(listener->F != NULL) {
        rb_close(listener->F);
        listener->F = NULL;
    }

    listener->active = 0;

    if(listener->ref_count)
        return;

    free_listener(listener);
}

/*
 * close_listeners - close and free all listeners that are not being used
 */
void
close_listeners()
{
    struct Listener *listener;
    struct Listener *listener_next = 0;
    /*
     * close all 'extra' listening ports we have
     */
    for (listener = ListenerPollList; listener; listener = listener_next) {
        listener_next = listener->next;
        close_listener(listener);
    }
}

#define DLINE_WARNING "ERROR :You have been D-lined.\r\n"

/*
 * add_connection - creates a client which has just connected to us on
 * the given fd. The sockhost field is initialized with the ip# of the host.
 * The client is sent to the auth module for verification, and not put in
 * any client list yet.
 */
static void
add_connection(struct Listener *listener, rb_fde_t *F, struct sockaddr *sai, struct sockaddr *lai, void *ssl_ctl)
{
    struct Client *new_client;
    s_assert(NULL != listener);

    /*
     * get the client socket name from the socket
     * the client has already been checked out in accept_connection
     */
    new_client = make_client(NULL);

    memcpy(&new_client->localClient->ip, sai, sizeof(struct rb_sockaddr_storage));
    memcpy(&new_client->preClient->lip, lai, sizeof(struct rb_sockaddr_storage));

    /*
     * copy address to 'sockhost' as a string, copy it to host too
     * so we have something valid to put into error messages...
     */
    rb_inet_ntop_sock((struct sockaddr *)&new_client->localClient->ip, new_client->sockhost,
                      sizeof(new_client->sockhost));


    rb_strlcpy(new_client->host, new_client->sockhost, sizeof(new_client->host));

    new_client->localClient->F = F;
    add_to_cli_fd_hash(new_client);
    new_client->localClient->listener = listener;
    new_client->localClient->ssl_ctl = ssl_ctl;
    if(ssl_ctl != NULL || rb_fd_ssl(F))
        SetSSL(new_client);

    ++listener->ref_count;

    start_auth(new_client);
}

static const char *toofast = "ERROR :Reconnecting too fast, throttled.\r\n";

static int
accept_precallback(rb_fde_t *F, struct sockaddr *addr, rb_socklen_t addrlen, void *data)
{
    struct Listener *listener = (struct Listener *)data;
    char buf[BUFSIZE];
    struct ConfItem *aconf;
    static time_t last_oper_notice = 0;
    int len;

    if(listener->ssl && (!ssl_ok || !get_ssld_count())) {
        rb_close(F);
        return 0;
    }

    if((maxconnections - 10) < rb_get_fd(F)) { /* XXX this is kinda bogus */
        ++ServerStats.is_ref;
        /*
         * slow down the whining to opers bit
         */
        if((last_oper_notice + 20) <= rb_current_time()) {
            sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                   "All connections in use. (%s)",
                                   get_listener_name(listener));
            last_oper_notice = rb_current_time();
        }

        rb_write(F, "ERROR :All connections in use\r\n", 32);
        rb_close(F);
        /* Re-register a new IO request for the next accept .. */
        return 0;
    }

    aconf = find_dline(addr, addr->sa_family);
    if(aconf != NULL && (aconf->status & CONF_EXEMPTDLINE))
        return 1;

    /* Do an initial check we aren't connecting too fast or with too many
     * from this IP... */
    if(aconf != NULL) {
        ServerStats.is_ref++;

        if(ConfigFileEntry.dline_with_reason) {
            len = snprintf(buf, sizeof(buf), "ERROR :*** Banned: %s\r\n", get_user_ban_reason(aconf));
            if (len >= (int)(sizeof(buf)-1)) {
                buf[sizeof(buf) - 3] = '\r';
                buf[sizeof(buf) - 2] = '\n';
                buf[sizeof(buf) - 1] = '\0';
            }
        } else
            strcpy(buf, "ERROR :You have been D-lined.\r\n");

        rb_write(F, buf, strlen(buf));
        rb_close(F);
        return 0;
    }

    if(check_reject(F, addr))
        return 0;

    if(throttle_add(addr)) {
        rb_write(F, toofast, strlen(toofast));
        rb_close(F);
        return 0;
    }

    return 1;
}

static void
accept_ssld(rb_fde_t *F, struct sockaddr *addr, struct sockaddr *laddr, struct Listener *listener)
{
    ssl_ctl_t *ctl;
    rb_fde_t *xF[2];
    if(rb_socketpair(AF_UNIX, SOCK_STREAM, 0, &xF[0], &xF[1], "Incoming ssld Connection") == -1) {
        ilog_error("creating SSL/TLS socket pairs");
        rb_close(F);
        return;
    }
    ctl = start_ssld_accept(F, xF[1], rb_get_fd(xF[0])); /* this will close F for us */
    add_connection(listener, xF[0], addr, laddr, ctl);
}

static void
accept_callback(rb_fde_t *F, int status, struct sockaddr *addr, rb_socklen_t addrlen, void *data)
{
    struct Listener *listener = data;
    struct rb_sockaddr_storage lip;
    unsigned int locallen = sizeof(struct rb_sockaddr_storage);

    ServerStats.is_ac++;

    if(getsockname(rb_get_fd(F), (struct sockaddr *) &lip, &locallen) < 0) {
        /* this can fail if the connection disappeared in the meantime */
        rb_close(F);
        return;
    }

    if(listener->ssl)
        accept_ssld(F, addr, (struct sockaddr *)&lip, listener);
    else
        add_connection(listener, F, addr, (struct sockaddr *)&lip, NULL);
}