source: irc_cap.c @ ff9f3e3

/********************************************************************\
  * BitlBee -- An IRC to other IM-networks gateway                     *
  *                                                                    *
  * Copyright 2002-2013 Wilmer van der Gaast and others                *
  \********************************************************************/

/* IRCv3 CAP command
 *
 * Specs:
 *  - v3.1: http://ircv3.net/specs/core/capability-negotiation-3.1.html
 *  - v3.2: http://ircv3.net/specs/core/capability-negotiation-3.2.html
 *
 * */

/*
  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 with
  the Debian GNU/Linux distribution in /usr/share/common-licenses/GPL;
  if not, write to the Free Software Foundation, Inc., 51 Franklin St.,
  Fifth Floor, Boston, MA  02110-1301  USA
*/

#include "bitlbee.h"

typedef struct {
        char *name;
        irc_cap_flag_t flag;
} cap_info_t;

static const cap_info_t supported_caps[] = {
        {"sasl", CAP_SASL},
        {"multi-prefix", CAP_MULTI_PREFIX},
        {"extended-join", CAP_EXTENDED_JOIN},
        {"away-notify", CAP_AWAY_NOTIFY},
        {"userhost-in-names", CAP_USERHOST_IN_NAMES},
        {"server-time", CAP_SERVER_TIME},
        {NULL},
};

static irc_cap_flag_t cap_flag_from_string(char *cap_name)
{
        int i;

        if (!cap_name || !cap_name[0]) {
                return 0;
        }

        if (cap_name[0] == '-') {
                cap_name++;
        }

        for (i = 0; supported_caps[i].name; i++) {
                if (strcmp(supported_caps[i].name, cap_name) == 0) {
                        return supported_caps[i].flag;
                }
        }
        return 0;
}

static gboolean irc_cmd_cap_req(irc_t *irc, char *caps)
{
        int i;
        char *lower = NULL;
        char **split = NULL;
        irc_cap_flag_t new_caps = irc->caps;

        if (!caps || !caps[0]) {
                return FALSE;
        }

        lower = g_ascii_strdown(caps, -1);
        split = g_strsplit(lower, " ", -1);
        g_free(lower);

        for (i = 0; split[i]; i++) {
                gboolean remove;
                irc_cap_flag_t flag;

                if (!split[i][0]) {
                        continue;   /* skip empty items (consecutive spaces) */
                }

                remove = (split[i][0] == '-');
                flag = cap_flag_from_string(split[i]);
                
                if (!flag || (remove && !(irc->caps & flag))) {
                        /* unsupported cap, or removing something that isn't there */
                        g_strfreev(split);
                        return FALSE;
                }

                if (remove) {
                        new_caps &= ~flag;
                } else {
                        new_caps |= flag;
                }
        }

        /* if we got here, set the new caps and ack */
        irc->caps = new_caps;

        g_strfreev(split);
        return TRUE;
}

/* version can be 0, 302, 303, or garbage from user input. thanks user input */
static void irc_cmd_cap_ls(irc_t *irc, long version)
{
        int i;
        GString *str = g_string_sized_new(256);

        for (i = 0; supported_caps[i].name; i++) {
                if (i != 0) {
                        g_string_append_c(str, ' ');
                }
                g_string_append(str, supported_caps[i].name);

                if (version >= 302 && supported_caps[i].flag == CAP_SASL) {
                        g_string_append(str, "=PLAIN");
                }
        }

        irc_send_cap(irc, "LS", str->str);

        g_string_free(str, TRUE);
}

/* this one looks suspiciously similar to cap ls,
 * but cap-3.2 will make them very different */
static void irc_cmd_cap_list(irc_t *irc)
{
        int i;
        gboolean first = TRUE;
        GString *str = g_string_sized_new(256);

        for (i = 0; supported_caps[i].name; i++) {
                if (irc->caps & supported_caps[i].flag) {
                        if (!first) {
                                g_string_append_c(str, ' ');
                        }
                        first = FALSE;

                        g_string_append(str, supported_caps[i].name);
                }
        }

        irc_send_cap(irc, "LIST", str->str);

        g_string_free(str, TRUE);
}

void irc_cmd_cap(irc_t *irc, char **cmd)
{
        if (!(irc->status & USTATUS_LOGGED_IN)) {
                /* Put registration on hold until CAP END */
                irc->status |= USTATUS_CAP_PENDING;
        }

        if (g_strcasecmp(cmd[1], "LS") == 0) {
                irc_cmd_cap_ls(irc, cmd[2] ? strtol(cmd[2], NULL, 10) : 0);

        } else if (g_strcasecmp(cmd[1], "LIST") == 0) {
                irc_cmd_cap_list(irc);

        } else if (g_strcasecmp(cmd[1], "REQ") == 0) {
                gboolean ack = irc_cmd_cap_req(irc, cmd[2]);

                irc_send_cap(irc, ack ? "ACK" : "NAK", cmd[2] ? : "");

        } else if (g_strcasecmp(cmd[1], "END") == 0) {
                if (!(irc->status & USTATUS_CAP_PENDING)) {
                        return;
                }
                irc->status &= ~USTATUS_CAP_PENDING;

                if (irc->status & USTATUS_SASL_PLAIN_PENDING) {
                        irc_send_num(irc, 906, ":SASL authentication aborted");
                        irc->status &= ~USTATUS_SASL_PLAIN_PENDING;
                }

                irc_check_login(irc);

        } else {
                irc_send_num(irc, 410, "%s :Invalid CAP command", cmd[1]);
        }

}