+/**
+ * Forward JOIN command to a specific server
+ *
+ * This function diffentiates between servers using RFC 2813 mode that
+ * support the JOIN command with appended ASCII 7 character and channel
+ * modes, and servers using RFC 1459 protocol which require separate JOIN
+ * and MODE commands.
+ *
+ * @param To Forward JOIN (and MODE) command to this peer server
+ * @param Prefix Client used to prefix the genrated commands
+ * @param Data Parameters of JOIN command to forward, probably
+ * containing channel modes separated by ASCII 7.
+ */
+static void
+cb_join_forward(CLIENT *To, CLIENT *Prefix, void *Data)
+{
+ CONN_ID conn;
+ char str[COMMAND_LEN], *ptr = NULL;
+
+ strlcpy(str, (char *)Data, sizeof(str));
+ conn = Client_Conn(To);
+
+ if (Conn_Options(conn) & CONN_RFC1459) {
+ /* RFC 1459 compatibility mode, appended modes are NOT
+ * supported, so strip them off! */
+ ptr = strchr(str, 0x7);
+ if (ptr)
+ *ptr++ = '\0';
+ }
+
+ IRC_WriteStrClientPrefix(To, Prefix, "JOIN %s", str);
+ if (ptr && *ptr)
+ IRC_WriteStrClientPrefix(To, Prefix, "MODE %s +%s %s", str, ptr,
+ Client_ID(Prefix));
+} /* cb_join_forward */
+
+
+/**
+ * Forward JOIN command to all servers
+ *
+ * This function calls cb_join_forward(), which differentiates between
+ * protocol implementations (e.g. RFC 2812, RFC 1459).
+ *
+ * @param Client Client used to prefix the genrated commands
+ * @param target Forward JOIN (and MODE) command to this peer server
+ * @param chan Channel structure
+ * @param channame Channel name
+ */
+static void
+join_forward(CLIENT *Client, CLIENT *target, CHANNEL *chan,
+ const char *channame)
+{
+ char modes[CHANNEL_MODE_LEN], str[COMMAND_LEN];
+
+ /* RFC 2813, 4.2.1: channel modes are separated from the channel
+ * name with ASCII 7, if any, and not spaces: */
+ strlcpy(&modes[1], Channel_UserModes(chan, target), sizeof(modes) - 1);
+ if (modes[1])
+ modes[0] = 0x7;
+ else
+ modes[0] = '\0';
+
+ /* forward to other servers (if it is not a local channel) */
+ if (!Channel_IsLocal(chan)) {
+ snprintf(str, sizeof(str), "%s%s", channame, modes);
+ IRC_WriteStrServersPrefixFlag_CB(Client, target, '\0',
+ cb_join_forward, str);
+ }
+
+ /* tell users in this channel about the new client */
+ IRC_WriteStrChannelPrefix(Client, chan, target, false,
+ "JOIN :%s", channame);
+
+ /* synchronize channel modes */
+ if (modes[1]) {
+ IRC_WriteStrChannelPrefix(Client, chan, target, false,
+ "MODE %s +%s %s", channame,
+ &modes[1], Client_ID(target));
+ }
+} /* join_forward */
+
+
+/**
+ * Aknowledge user JOIN request and send "channel info" numerics.
+ *
+ * @param Client Client used to prefix the genrated commands
+ * @param target Forward commands/numerics to this user
+ * @param chan Channel structure
+ * @param channame Channel name
+ */
+static bool
+join_send_topic(CLIENT *Client, CLIENT *target, CHANNEL *chan,
+ const char *channame)
+{
+ const char *topic;
+
+ if (Client_Type(Client) != CLIENT_USER)
+ return true;
+ /* acknowledge join */
+ if (!IRC_WriteStrClientPrefix(Client, target, "JOIN :%s", channame))
+ return false;
+
+ /* Send topic to client, if any */
+ topic = Channel_Topic(chan);
+ assert(topic != NULL);
+ if (*topic) {
+ if (!IRC_WriteStrClient(Client, RPL_TOPIC_MSG,
+ Client_ID(Client), channame, topic))
+ return false;
+#ifndef STRICT_RFC
+ if (!IRC_WriteStrClient(Client, RPL_TOPICSETBY_MSG,
+ Client_ID(Client), channame,
+ Channel_TopicWho(chan),
+ Channel_TopicTime(chan)))
+ return false;
+#endif
+ }
+ /* send list of channel members to client */
+ if (!IRC_Send_NAMES(Client, chan))
+ return false;
+ return IRC_WriteStrClient(Client, RPL_ENDOFNAMES_MSG, Client_ID(Client),
+ Channel_Name(chan));
+} /* join_send_topic */
+
+
+/**
+ * Handler for the IRC "JOIN" command.
+ *
+ * See RFC 2812, 3.2.1 "Join message"; RFC 2813, 4.2.1 "Join message".
+ *
+ * @param Client The client from which this command has been received
+ * @param Req Request structure with prefix and all parameters
+ * @returns CONNECTED or DISCONNECTED
+ */
+GLOBAL bool
+IRC_JOIN( CLIENT *Client, REQUEST *Req )
+{
+ char *channame, *key = NULL, *flags, *lastkey = NULL, *lastchan = NULL;
+ CLIENT *target;
+ CHANNEL *chan;
+
+ assert (Client != NULL);
+ assert (Req != NULL);
+
+ /* Bad number of arguments? */
+ if (Req->argc < 1 || Req->argc > 2)
+ return IRC_WriteStrClient(Client, ERR_NEEDMOREPARAMS_MSG,
+ Client_ID(Client), Req->command);
+
+ /* Who is the sender? */
+ if (Client_Type(Client) == CLIENT_SERVER)
+ target = Client_Search(Req->prefix);
+ else
+ target = Client;
+
+ if (!target)
+ return IRC_WriteStrClient(Client, ERR_NOSUCHNICK_MSG,
+ Client_ID(Client), Req->prefix);
+
+ /* Is argument "0"? */
+ if (Req->argc == 1 && !strncmp("0", Req->argv[0], 2))
+ return part_from_all_channels(Client, target);
+
+ /* Are channel keys given? */
+ if (Req->argc > 1)
+ key = strtok_r(Req->argv[1], ",", &lastkey);
+
+ channame = Req->argv[0];
+ channame = strtok_r(channame, ",", &lastchan);
+
+ /* Make sure that "channame" is not the empty string ("JOIN :") */
+ if (! channame)
+ return IRC_WriteStrClient(Client, ERR_NEEDMOREPARAMS_MSG,
+ Client_ID(Client), Req->command);
+
+ while (channame) {
+ flags = NULL;
+
+ /* Did the server include channel-user-modes? */
+ if (Client_Type(Client) == CLIENT_SERVER) {
+ flags = strchr(channame, 0x7);
+ if (flags) {
+ *flags = '\0';
+ flags++;
+ }