Add chmode +N, which prevents nickchanges.

help/opers/cmode

@@ -33,6 +33,8 @@ NO PARAMETERS:
      +T     - Disable notice. All notices to the channel are disallowed.
      +E     - No kicks. Chanops will not be able to use /kick on this
               channel.
+     +N     - No nickchanges. People on the channel will not be able to
+              change nick.
 
 WITH PARAMETERS:
      +f     - Forward.  Forwards users who cannot join because of +i,

include/channel.h

@@ -175,6 +175,7 @@ typedef int (*ExtbanFunc)(const char *data, struct Client *client_p,
 #define MODE_NONOTICE	0x16000	/* Block notices directed to this channel */
 #define MODE_NOACTION	0x32000 /* Block CTCP ACTION directed to this channel */
 #define MODE_NOKICK	0x64000 /* Disable /kick on this channel */
+#define MODE_NONICK	0x128000 /* Disable /nick for anyone on this channel */
 
 #define CHFL_BAN        0x10000000	/* ban channel flag */
 #define CHFL_EXCEPTION  0x20000000	/* exception to ban channel flag */
@@ -243,6 +244,8 @@ const char *channel_modes(struct Channel *chptr, struct Client *who);
 
 extern struct Channel *find_bannickchange_channel(struct Client *client_p);
 
+extern struct Channel *find_nonickchange_channel(struct Client *client_p);
+
 extern void check_spambot_warning(struct Client *source_p, const char *name);
 
 extern void check_splitmode(void *);

include/numeric.h

@@ -264,6 +264,8 @@ extern const char *form_str(int);
 
 #define ERR_NOINVITE	     447
 
+#define ERR_NONICK	     449
+
 #define ERR_NOTREGISTERED    451
 
 #define ERR_ACCEPTFULL       456

modules/core/m_nick.c

@@ -691,6 +691,16 @@ change_local_nick(struct Client *client_p, struct Client *source_p,
 					nick, chptr->chname);
 			return;
 		}
+
+		chptr = find_nonickchange_channel(source_p);
+		if (chptr != NULL)
+		{
+			sendto_one_numeric(source_p, ERR_NONICK,
+					form_str(ERR_NONICK),
+					chptr->chname);
+			return;
+		}
+
 		if((source_p->localClient->last_nick_change + ConfigFileEntry.max_nick_time) < rb_current_time())
 			source_p->localClient->number_of_nick_changes = 0;
 

src/channel.c

@@ -904,6 +904,32 @@ find_bannickchange_channel(struct Client *client_p)
 	return NULL;
 }
 
+/* find_nonickchange_channel()
+ * Input: client to check
+ * Output: channel preventing nick change
+ */
+struct Channel *
+find_nonickchange_channel(struct Client *client_p)
+{
+	struct Channel *chptr;
+	struct membership *msptr;
+	rb_dlink_node *ptr;
+
+	if (!MyClient(client_p))
+		return NULL;
+
+	RB_DLINK_FOREACH(ptr, client_p->user->channel.head)
+	{
+		msptr = ptr->data;
+		chptr = msptr->chptr;
+		if (is_chanop_voiced(msptr))
+			continue;		
+		if (chptr->mode.mode & MODE_NONICK)
+			return chptr;
+	}
+	return NULL;
+}
+
 /* void check_spambot_warning(struct Client *source_p)
  * Input: Client to check, channel name or NULL if this is a part.
  * Output: none

src/chmode.c

@@ -1410,7 +1410,7 @@ struct ChannelMode chmode_table[256] =
   {chm_nosuch,	0 },			/* K */
   {chm_staff,	MODE_EXLIMIT },		/* L */
   {chm_nosuch,	0 },			/* M */
-  {chm_nosuch,	0 },			/* N */
+  {chm_simple,	MODE_NONICK },		/* N */
   {chm_nosuch,	0 },			/* O */
   {chm_staff,	MODE_PERMANENT },	/* P */
   {chm_simple,	MODE_DISFORWARD },	/* Q */

src/messages.tab

@@ -470,7 +470,7 @@ static  const char *  replies[] = {
 /* 446 ERR_USERSDISABLED, */	NULL,
 /* 447 ERR_NOINVITE */       	":Can't send invite to %s (+V set)",
 /* 448 */       NULL,
-/* 449 */       NULL,
+/* 449 ERR_NONICK */		"%s :Cannot change nickname while on channel (+N set)",
 /* 450 */       NULL,
 /* 451 ERR_NOTREGISTERED, */    ":%s 451 * :You have not registered",
 /* 452 */       NULL,