Add os_dns, a way to control your DNS zone via services

data/example.conf

@@ -281,6 +281,13 @@ networkinfo
  */
 options
 {
+	/*
+	 * On Linux/UNIX systems Anope can setuid and setgid to this user and group
+	 * after starting up. This is useful if Anope has to bind to privileged ports
+	 */
+	#user = "anope"
+	#group = "anope"
+
 	/*
 	 * The case mapping used by services. This must be set to a valid locale name
 	 * installed on your machine. Services use this case map to compare, with
@@ -1047,6 +1054,15 @@ dns
 	 * How long to wait in seconds before a DNS query has timed out
 	 */
 	timeout = 5
+
+	/*
+	 * The port services use to listen for DNS queries.
+	 * Note that ports less than 1024 are privileged on UNIX/Linux systems, and
+	 * require Anope to be started as root. If you do this, it is recommended you
+	 * set options:user and options:group so Anope can change users after binding
+	 * to this port.
+	 */
+	port = 53
 }
 
 /*

data/operserv.example.conf

@@ -355,15 +355,61 @@ defcon
 }
 
 /*
- * os_list
+ * os_dns
  *
- * Provides the commands operserv/chanlist and operserv/userlist.
+ * Provides the command operserv/dns.
  *
- * Used to list and search the channels and users currently on the network.
+ * This module allows controlling a DNS zone. This is useful for
+ * controlling what servers users are placed on for load balancing,
+ * and to automatically remove split servers.
+ *
+ * To use this module you must set a nameserver record for services
+ * so that DNS queries go to services.
+ *
+ * We recommend you use something similar to BIND's query forwarding
+ * ability to hide service's IP, provide query caching, and provide
+ * better fault tolerance. To do this, configure BIND similar to:
+ *
+ * options {
+ *   dnssec-enable no;
+ *   dnssec-validation no;
+ * };
+ * zone "irc.example.com" IN {
+ *   type forward;
+ *   forward first;
+ *   forwarders { 10.0.0.1 port 5353; }; # Where this is the IP and dns:port of services
+ * };
+ *
+ * And then set a NS record for irc.example.com. to BIND.
  */
-module { name = "os_list" }
-command { service = "OperServ"; name = "CHANLIST"; command = "operserv/chanlist"; }
-command { service = "OperServ"; name = "USERLIST"; command = "operserv/userlist"; }
+#module { name = "os_dns" }
+#command { service = "OperServ"; name = "DNS"; command = "operserv/dns"; permission = "operserv/dns"; }
+os_dns
+{
+	/* TTL for records. This should be very low if your records change often. */
+	ttl = 1m
+
+	/* If a server drops this many users the server is automatically removed from the DNS zone.
+	 * This directive is optional.
+	 */
+	user_drop_mark = 50
+
+	/* The time used for user_drop_mark */
+	user_drop_time = 1m
+
+	/* When a server is removed from the zone for dropping users, it is readded after this time.
+	 * This directive is optional.
+	 */
+	user_drop_readd_time = 5m
+
+	/* If set, if a server splits it is automatically removed from the zone */
+	remove_split_servers = yes
+
+	/* If set, when a server connects to the network it will be automatically added to
+	 * the zone if it is a known server.
+	 */
+	readd_connected_servers = no
+}
 
 /*
  * os_config
@@ -425,6 +471,17 @@ command { service = "OperServ"; name = "KICK"; command = "operserv/kick"; permis
 module { name = "os_kill" }
 command { service = "OperServ"; name = "KILL"; command = "operserv/kill"; permission = "operserv/kill"; }
 
+/*
+ * os_list
+ *
+ * Provides the commands operserv/chanlist and operserv/userlist.
+ *
+ * Used to list and search the channels and users currently on the network.
+ */
+module { name = "os_list" }
+command { service = "OperServ"; name = "CHANLIST"; command = "operserv/chanlist"; }
+command { service = "OperServ"; name = "USERLIST"; command = "operserv/userlist"; }
+
 /*
  * os_login
  *

include/config.h

@@ -394,6 +394,10 @@ class CoreExport ServerConfig
 	/* Max length of channel names */
 	unsigned ChanLen;
 
+	/* User and group to run as */
+	Anope::string User;
+	Anope::string Group;
+
 	/* Casemapping to use */
 	Anope::string CaseMap;
 
@@ -494,8 +498,10 @@ class CoreExport ServerConfig
 
 	/* Nameserver to use for resolving hostnames */
 	Anope::string NameServer;
-	/* TIme before a DNS query is considered dead */
+	/* Time before a DNS query is considered dead */
 	time_t DNSTimeout;
+	/* The port DNS queries come in on */
+	int DNSPort;
 
 	/* Prefix of guest nicks when a user gets forced off of a nick */
 	Anope::string NSGuestNickPrefix;

include/dns.h

@@ -95,7 +95,6 @@ struct CoreExport DNSQuery
 
 	DNSQuery();
 	DNSQuery(const Question &q);
-	DNSQuery(const DNSPacket &p);
 };
 
 /** The request
@@ -124,7 +123,7 @@ class CoreExport DNSRequest : public Timer, public Question
 	void Tick(time_t) anope_override;
 };
 
-/** A full packet sent or recieved to/from the nameserver, may contain multiple queries
+/** A full packet sent or recieved to/from the nameserver
  */
 class DNSPacket : public DNSQuery
 {
@@ -139,12 +138,14 @@ class DNSPacket : public DNSQuery
  public:
 	static const int HEADER_LENGTH = 12;
 
-	/* Our 16-bit id for this header */
+	/* Source or destination of the packet */
+	sockaddrs addr;
+	/* ID for this packet */
 	unsigned short id;
-	/* Flags on the query */
+	/* Flags on the packet */
 	unsigned short flags;
 
-	DNSPacket();
+	DNSPacket(const sockaddrs &a);
 	void Fill(const unsigned char *input, const unsigned short len);
 	unsigned short Pack(unsigned char *output, unsigned short output_size);
 };
@@ -155,20 +156,19 @@ class CoreExport DNSManager : public Timer, public Socket
 {
 	typedef std::multimap<Anope::string, ResourceRecord, ci::less> cache_map;
 	cache_map cache;
-	sockaddrs addrs;
- public:
+
 	std::deque<DNSPacket *> packets;
+ public:
+	sockaddrs addrs;
 	std::map<unsigned short, DNSRequest *> requests;
 
-	static const int DNSPort = 53;
-
 	DNSManager(const Anope::string &nameserver, int port);
 
 	~DNSManager();
 
-	bool ProcessRead();
+	bool ProcessRead() anope_override;
 
-	bool ProcessWrite();
+	bool ProcessWrite() anope_override;
 
 	/** Add a record to the dns cache
 	 * @param r The record
@@ -189,6 +189,15 @@ class CoreExport DNSManager : public Timer, public Socket
 	 */
 	void Cleanup(Module *mod);
 
+	/** Get the list of packets pending to be sent
+	 */
+	std::deque<DNSPacket *>& GetPackets();
+
+	/** Queues a packet for sending
+	 * @param p The packet
+	 */
+	void SendPacket(DNSPacket *p);
+
 	/** Does a BLOCKING DNS query and returns the first IP.
 	 * Only use this if you know what you are doing. Unless you specifically
 	 * need a blocking query use the DNSRequest system

include/modules.h

@@ -917,6 +917,11 @@ class CoreExport Module : public Extensible
 	 */
 	virtual void OnLog(Log *l) { }
 
+	/** Called when a DNS request (question) is recieved.
+	 * @param req The dns request
+	 */
+	virtual void OnDnsRequest(DNSPacket &req) { }
+
 	/** Called when a channels modes are being checked to see if they are allowed,
 	 * mostly to ensure mlock/+r are set.
 	 * @param c The channel
@@ -995,7 +1000,7 @@ enum Implementation
 		I_OnServerQuit, I_OnTopicUpdated,
 		I_OnEncrypt, I_OnDecrypt,
 		I_OnChannelModeSet, I_OnChannelModeUnset, I_OnUserModeSet, I_OnUserModeUnset, I_OnChannelModeAdd, I_OnUserModeAdd,
-		I_OnMLock, I_OnUnMLock, I_OnServerSync, I_OnUplinkSync, I_OnBotPrivmsg, I_OnPrivmsg, I_OnLog,
+		I_OnMLock, I_OnUnMLock, I_OnServerSync, I_OnUplinkSync, I_OnBotPrivmsg, I_OnPrivmsg, I_OnLog, I_OnDnsRequest,
 
 		I_OnSerializeCheck, I_OnSerializableConstruct, I_OnSerializableDestruct, I_OnSerializableUpdate,
 	I_END

include/servers.h

@@ -63,6 +63,9 @@ class CoreExport Server : public Flags<ServerFlag>
 	~Server();
 
  public:
+ 	/* Number of users on the server */
+ 	unsigned Users;
+
 	/** Delete this server with a reason
 	 * @param reason The reason
 	 */