gated Daemon

AIX Version 4.3 Commands Reference, Volume 2

gated Daemon

Purpose

Provides gateway routing functions for the RIP, RIPng, EGP, BGP, BGP4+, HELLO, IS-IS, ICMP, ICMPv6, and SNMP protocols.

Note: Use SRC commands to control the gated daemon from the command line. Use the rc.tcpip file to start the daemon with each system startup.

Syntax

/usr/sbin/gated [ -c ] [ -C ] [ -n ] [ -N ] [ -t TraceOptions ] [ -f ConfigFile ] [ TraceFile ]

Description

The /usr/sbin/gated daemon handles multiple routing protocols and replaces routed and any routing daemon that speaks the (HELLO) routing protocol. The /usr/sbin/gated daemon currently handles the Routing Information Protocol (RIP), Routing Information Protocol Next Generation (RIPng), Exterior Gateway Protocol (EGP), Border Gateway Protocol (BGP) and BGP4+, Defense Communications Network Local-Network Protocol (HELLO), and Open Shortest Path First (OSPF), Intermediate System to Intermediate System (IS-IS), and Internet Control Message Protocol (ICMP) / Router Discovery routing protocols. In addition, the gated daemon supports the Simple Network Management Protocol (SNMP). The gated process can be configured to perform all of these protocols or any combination of them. The default configuration file for the gated daemon is the /etc/gated.conf file. The gated daemon stores its process ID in the /etc/gated.pid file.

Note: Unpredictable results may occur when the gated and routed daemons are run together on the same host.

If on the command line a trace file is specified, or no trace flags are specified, the gated daemon detaches from the terminal and runs in the background. If trace flags are specified without specifying a trace file, gated assumes that tracing is desired to stderr and remains in the foreground.

Signals

The gated server performs the following actions when you use the kill command to send it signals.

SIGHUP	Re-read configuration. A SIGHUP causes gated to reread the configuration file. The gated daemon first performs a clean-up of all allocated policy structures. All BGP and EGP peers are flagged for deletion and the configuration file is reparsed. If the reparse is successful, any BGP and EGP peers that are no longer in the configuration are shut down, and new peers are started. The gated daemon attempts to determine if changes to existing peers require a shutdown and restart. Note: Reconfiguration is disable when OSPF (Open Shortest Path First) is enabled.
SIGINT	Snap-shot of current state. The current state of all gated tasks, timers, protocols and tables are written to /var/tmp/gated_dump. On AIX systems, this is done by forking a subprocess to dump the table information so as not to impact the gated daemon's routing functions.
SIGTERM	Graceful shutdown. Upon receiving a SIGTERM signal, the gated daemon attempts a graceful shutdown. All tasks and protocols are asked to shutdown. Most will terminate immediately, the exception being EGP peers which wait for confirmation. It may be necessary to repeat the SIGTERM once or twice if this process takes too long. All protocol routes are removed from the kernel's routing table on receipt of a SIGTERM. Interface routes, routes with RTF_STATIC set (from the route command where supported) and static routes specifying retain will remain. To terminate the gated daemon with the exterior routes intact, use the SIGKILL or SIGQUIT signals (which causes a core dump).
SIGUSR1	Toggle tracing. Upon receiving a SIGUSR1 signal, the gated daemon will close the trace file. A subsequent SIGUSR1 will cause it to be reopened. This will allow the file to be moved regularly. Note: It is not possible to use the SIGUSR1 signal if a trace file has not been specified, or tracing is being performed to stderr.
SIGUSR2	Check for interface changes. Upon receiving a SIGUSR2 signal, the gated daemon rescans the kernel interface list looking for changes.

The gated and snmpd Daemons

The gated daemon is internally configured to be an SNMP multiplexing (SMUX) protocol peer, or proxy agent, of the snmpd daemon. For more information, refer to "SNMP Daemon Processing" in AIX Version 4.3 System Management Guide: Communications and Networks.

Manipulating the gated Daemon with the System Resource Controller

The gated daemon can be controlled by the System Resource Controller (SRC). The gated daemon is a member of the SRC tcpip system group. This daemon is disabled by default and can be manipulated by the following SRC commands:

startsrc	Starts a subsystem, group of subsystems, or a subserver.
stopsrc	Stops a subsystem, group of subsystems, or a subserver.
refresh	Causes the subsystem or group of subsystems to reread the appropriate configuration file.
lssrc	Gets the status of a subsystem, group of subsystems, or a subserver.

Note: On initial startup from the startsrc command, the gated daemon does not start responding to other SRC commands until all gated initialization is completed. A very large /etc/gated.conf file can require a minute or more to parse completely.

Flags

-c	Specifies parsing of the configuration file for syntax errors after which the gated daemon exits. If no errors occur, the gated daemon puts a dump file into the /var/tmp/gated_dump file. The -c flag implies the -tgeneral,kernel,nostamp flag. If the -c flag is specified, the gated daemon ignores all traceoption and tracefile clauses in the configuration file.
-C	Specifies that the configuration file is parsed only for syntax errors. The gated daemon exists with a status of 1 if it finds any errors and with a status of 0 if it does not. The -C flag implies the -tnostamp flag.
-f ConfigFile	Specifies an alternate configuration file. By default, the gated daemon uses the /etc/gated.conf file.
-n	Specifies that the gated daemon will not modify the kernel's routing table. This is used for testing gated configurations with actual routing data.
-N	Specifies that the gated daemon does not daemonize. Normally, if tracing to stderr is not specified and the parent process ID is not 1, the gated daemon daemonizes. This flag allows the use of a method similar to /etc/inittab of invoking the gated daemon that does not have a process ID of 1.
-tTraceOptions	Specifies which trace options are enabled at system startup. When used without the TraceOptions variable, this flag starts the general trace options. Separate each trace option from another with a comma. Do not insert a space between the flag and the first trace option. The -t flag must be used to trace events that take place before the /etc/gated.conf file is parsed, such as determining the interface configuration and reading routes from the kernel. The gated.conf file article describes the available trace options.

Examples

To start the gated daemon, enter a command similar to the following:
```
startsrc -s gated -a "-tall /var/tmp/gated.log"
```
This command starts the gated daemon and logs messages. Messages are sent to the /var/tmp/gated.log file.
To stop the gated daemon normally, enter:
```
stopsrc -s gated
```
This command stops the daemon. The -s flag specifies that the subsystem that follows is to be stopped.
To get short status from the gated daemon, enter:
```
lssrc -s gated
```
This command returns the name of the daemon, the process ID of the daemon, and the state of the daemon (active or inactive).

Files

/etc/gated.pid	Contains the gated process ID.
/var/tmp/gated_dump	Specifies the memory dump file.
/var/tmp/gated.log	Specifies the log file for error messages.

Related Information

The kill command, gdc command, ospf_monitor command, and ripquery command,

The routed daemon.

The gated.conf file format.

How to Configure the gated Daemon in AIX Version 4.3 System Management Guide: Communications and Networks.

TCP/IP Routing, TCP/IP Protocols, TCP/IP Daemons in AIX Version 4.3 System Management Guide: Communications and Networks.