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diff --git a/sbin/routed/routed.8 b/sbin/routed/routed.8 new file mode 100644 index 0000000..de3abf3 --- /dev/null +++ b/sbin/routed/routed.8 @@ -0,0 +1,605 @@ +.\" Copyright (c) 1983, 1991, 1993 +.\" The Regents of the University of California. All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. All advertising materials mentioning features or use of this software +.\" must display the following acknowledgement: +.\" This product includes software developed by the University of +.\" California, Berkeley and its contributors. +.\" 4. Neither the name of the University nor the names of its contributors +.\" may be used to endorse or promote products derived from this software +.\" without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" @(#)routed.8 8.2 (Berkeley) 12/11/93 +.\" +.Dd June 1, 1996 +.Dt ROUTED 8 +.Os BSD 4.4 +.Sh NAME +.Nm routed +.Nd network RIP and router discovery routing daemon +.Sh SYNOPSIS +.Nm +.Op Fl sqdghmpAt +.Op Fl T Ar tracefile +.Oo +.Fl F +.Ar net Ns Op /mask Ns Op ,metric +.Oc +.OP Fl P Ar parms +.Sh DESCRIPTION +.Nm Routed +is a dameon invoked at boot time to manage the network +routing tables. +It uses Routing Information Protocol, RIPv1 (RFC\ 1058), +RIPv2 (RFC\ 1723), +and Internet Router Discovery Protocol (RFC 1256) +to maintain the kernel routing table. +The RIPv1 protocol is based on the reference 4.3BSD daemon. +.Pp +It listens on the +.Xr udp 4 +socket for the +.Xr route 8 +service (see +.Xr services 5 ) +for Routing Information Protocol packets. +It also sends and receives multicast Router Discovery ICMP messages. +If the host is a router, +.Nm +periodically supplies copies +of its routing tables to any directly connected hosts and networks. +It also advertise or solicits default routes using Router Discovery +ICMP messages. +.Pp +When started (or when a network interface is later turned on), +.Nm +uses an AF_ROUTE address family facility to find those +directly connected interfaces configured into the +system and marked "up". +It adds necessary routes for the interfaces +to the kernel routing table. +Soon after being first started, and provided there is at least one +interface on which RIP has not been disabled, +.Nm +deletes all pre-existing +non-static routes in kernel table. +Static routes in the kernel table are preserved and +included in RIP responses if they have a valid RIP metric +(see +.Xr route 8 ). +.Pp +If more than one interface is present (not counting the loopback interface), +it is assumed that the host should forward packets among the +connected networks. +After transmitting a RIP +.Em request +and +Router Discovery Advertisements or Solicitations on a new interface, +the daemon enters a loop, listening for +RIP request and response and Router Discover packets from other hosts. +.Pp +When a +.Em request +packet is received, +.Nm +formulates a reply based on the information maintained in its +internal tables. +The +.Em response +packet generated contains a list of known routes, each marked +with a "hop count" metric (a count of 16 or greater is +considered "infinite"). +Advertised metrics reflect the metric associated with interface +(see +.Xr ifconfig 8 ), +so setting the metric on an interface +is an effective way to steer traffic. +.Pp +Responses do not contain routes with a first hop on the requesting +network to implement in part +.Em split-horizon . +Requests from query programs +such as +.Xr rtquery 8 +are answered with the complete table. +.Pp +The routing table maintained by the daemon +includes space for several gateways for each destination +to speed recovery from a failing router. +RIP +.Em response +packets received are used to update the routing tables provided they are +from one of the several currently recognized gateways or +advertise a better metric than at least one of the existing +gateways. +.Pp +When an update is applied, +.Nm +records the change in its own tables and updates the kernel routing table +if the best route to the destination changes. +The change in the kernel routing tableis reflected in the next batch of +.Em response +packets sent. +If the next response is not scheduled for a while, a +.Em flash update +response containing only recently changed routes is sent. +.Pp +In addition to processing incoming packets, +.Nm +also periodically checks the routing table entries. +If an entry has not been updated for 3 minutes, the entry's metric +is set to infinity and marked for deletion. +Deletions are delayed until the route has been advertised with +an infinite metric to insure the invalidation +is propagated throughout the local internet. +This is a form of +.Em poison reverse . +.Pp +Routes in the kernel table that are added or changed as a result +of ICMP Redirect messages are deleted after a while to minimize +.Em black-holes . +When a TCP connection suffers a timeout, +the kernel tells +.Nm routed , +which deletes all redirected routes +through the gateway involved, advances the age of all RIP routes through +the gateway to allow an alternate to be chosen, and advances of the +age of any relevant Router Discovery Protocol default routes. +.Pp +Hosts acting as internetwork routers gratuitously supply their +routing tables every 30 seconds to all directly connected hosts +and networks. +These RIP responses are sent to the broadcast address on nets that support +broadcasting, +to the destination address on point-to-point links, and to the router's +own address on other networks. +If RIPv2 is enabled, multicast packets are sent on interfaces that +support multicasting. +.Pp +If no response is received on a remote interface, if there are errors +while sending responses, +or if there are more errors than input or output (see +.Xr netstat 8 ), +then the cable or some other part of the interface is assumed to be +disconnected or broken, and routes are adjusted appropriately. +.Pp +The +.Em Internet Router Discovery Protocol +is handled similarly. +When the daemon is supplying RIP routes, it also listens for +Router Discovery Solicitations and sends Advertisements. +When it is quiet and only listening to other RIP routers, it +sends Solicitations and listens for Advertisements. +If it receives +a good Advertisement, it stops listening for broadcast or multicast +RIP responses. +It tracks several advertising routers to speed recovery when the +currently chosen router dies. +If all discovered routers disappear, +the daemon resumes listening to RIP responses. +.Pp +While using Router Discovery (which happens by default when +the system has a single network interface and a Router Discover Advertisement +is received), there is a single default route and a variable number of +redirected host routes in the kernel table. +.Pp +The Router Discover standard requires that advertisements +have a default "lifetime" of 30 minutes. That means should +something happen, a client can be without a good route for +30 minutes. It is a good idea to reduce the default to 45 +seconds using +.Fl P Cm rdisc_interval=45 +on the command line or +.Cm rdisc_interval=45 +in the +.Pa /etc/gateways +file. +.Pp +While using Router Discovery (which happens by default when +the system has a single network interface and a Router Discover Advertisement +is received), there is a single default route and a variable number of +redirected host routes in the kernel table. +.Pp +See the +.Cm pm_rdisc +facility described below to support "legacy" systems +that can handle neither RIPv2 nor Router Discovery. +.Pp +By default, neither Router Discovery advertisements nor solicications +are sent over point to point links (e.g. PPP). + +.Pp +Options supported by +.Nm routed : +.Bl -tag -width Ds +.It Fl s +this option forces +.Nm +to supply routing information. +This is the default if multiple network interfaces are present on which +RIP or Router Discovery have not been disabled, and if the kernel switch +ipforwarding=1. +.It Fl q +is the opposite of the +.Fl s +option. +.It Fl d +Do not run in the background. +This option is meant for interactive use. +.It Fl g +This flag is used on internetwork routers to offer a route +to the "default" destination. +It is equivalent to +.Fl F +.Cm 0/0,1 +and is present mostly for historical reasons. +A better choice is +.Fl P Cm pm_rdisc +on the command line or +.CM pm_rdisc in the +.Pa /etc/gateways +file. +since a larger metric +will be used, reducing the spread of the potentially dangerous +default route. +This is typically used on a gateway to the Internet, +or on a gateway that uses another routing protocol whose routes +are not reported to other local routers. +Notice that because a metric of 1 is used, this feature is +dangerous. It is more commonly accidently used to create chaos with routing +loop than to solve problems. +.It Fl h +This causes host or point-to-point routes to not be advertised, +provided there is a network route going the same direction. +That is a limited kind of aggregation. +This option is useful on gateways to ethernets that have other gateway +machines connected with point-to-point links such as SLIP. +.It Fl m +This causes the machine to advertise a host or point-to-point route to +its primary interface. +It is useful on multi-homed machines such as NFS servers. +This option should not be used except when the cost of +the host routes it generates is justified by the popularity of +the server. +It is effective only when the machine is supplying +routing information, because there is more than one interface. +The +.Fl m +option overrides the +.Fl q +option to the limited extent of advertising the host route. +.It Fl A +do not ignore RIPv2 authentication if we do not care about RIPv2 +authentication. +This option is required for conformance with RFC 1723. +However, it makes no sense and breaks using RIP as a discovery protocol +to ignore all RIPv2 packets that carry authentication when this machine +does not care about authentication. +.It Fl T Ar tracefile +increases the debugging level to at least 1 and +causes debugging information to be appended to the trace file. +Note that because of security concerns, it is wisest to not run +.Nm routed +routinely with tracing directed to a file. +.It Fl t +increases the debugging level, which causes more information to be logged +on the tracefile specified with +.Fl T +or standard out. +The debugging level can be increased or decreased +with the +.Em SIGUSR1 +or +.Em SIGUSR2 +signals or with the +.Cm rtquery +command. +.It Fl F Ar net[/mask][,metric] +minimize routes in transmissions via interfaces with addresses that match +.Em net/mask , +and synthesizes a default route to this machine with the +.Em metric . +The intent is to reduce RIP traffic on slow, point-to-point links +such as PPP links by replacing many large UDP packets of RIP information +with a single, small packet containing a "fake" default route. +If +.Em metric +is absent, a value of 14 is assumed to limit +the spread of the "fake" default route. + +This is a dangerous feature that when used carelessly can cause routing +loops. +Notice also that more than one interface can match the specified network +number and mask. +See also +.Fl g . +.It Fl P Ar parms +is equivalent to adding the parameter +line +.Em parms +to the +.Pa /etc/gateways +file. +.El +.Pp +Any other argument supplied is interpreted as the name +of a file in which the actions of +.Nm +should be logged. +It is better to use +.Fl T +instead of +appending the name of the trace file to the command. +.Pp +.Nm +also supports the notion of +"distant" +.Em passive +or +.Em active +gateways. +When +.Nm +is started, it reads the file +.Pa /etc/gateways +to find such distant gateways which may not be located using +only information from a routing socket, to discover if some +of the local gateways are +.Em passive , +and to obtain other parameters. +Gateways specified in this manner should be marked passive +if they are not expected to exchange routing information, +while gateways marked active +should be willing to exchange RIP packets. +Routes through +.Em passive +gateways are installed in the +kernel's routing tables once upon startup and are not included in +transmitted RIP responses. +.Pp +Distant active gateways are treated like network interfaces. +RIP responses are sent +to the distant +.Em active +gateway. +If no responses are received, the associated route is deleted from +the kernel table and RIP responses advertised via other interfaces. +If the distant gateway resumes sending RIP responses, the associated +route is restored. +.Pp +Such gateways can be useful on media that do not support broadcasts +or multicasts but otherwise act like classic shared media like +Ethernets such as some ATM networks. +One can list all RIP routers reachable on the ATM network in +.Pa /etc/gateways +with a series of +"host" lines. +.Pp +Gateways marked +.Em external +are also passive, but are not placed in the kernel +routing table nor are they included in routing updates. +The function of external entries is to indicate +that another routing process +will install such a route if ncessary, +and that alternate routes to that destination should not be installed +by +.Nm routed . +Such entries are only required when both routers may learn of routes +to the same destination. +.Pp +The +.Em /etc/gateways +file is comprised of a series of lines, each in +one of the following formats or consist of parameters described below: +.Pp +.Bd -ragged +.Cm net +.Ar Nname[/mask] +.Cm gateway +.Ar Gname +.Cm metric +.Ar value +.Pf < Cm passive No \&| +.Cm active No \&| +.Cm extern Ns > +.Ed +.Bd -ragged +.Cm host +.Ar Hname +.Cm gateway +.Ar Gname +.Cm metric +.Ar value +.Pf < Cm passive No \&| +.Cm active No \&| +.Cm extern Ns > +.Ed +.Pp +.Ar Nname +or +.Ar Hname +is the name of the destination network or host. +It may be a symbolic network name or an Internet address +specified in "dot" notation (see +.Xr inet 3 ). +(If it is a name, then it must either be defined in +.Pa /etc/networks +or +.Pa /etc/hosts , +or +.Xr named 8 , +must have been started before +.Xr routed Ns .) +.Pp +.Ar mask +is an optional number between 1 and 32 indicating the netmask associated +with +.Ar Nname . +.Pp +.Ar Gname +is the name or address of the gateway to which RIP responses should +be forwarded. +.Pp +.Ar Value +is the hop count to the destination host or network. +.Ar " host hname " +is equivalent to +.Ar " net nname/32 ". +.Pp +One of the keywords +.Cm passive , +.Cm active +or +.Cm external +must be present to indicate whether the gateway should be treated as +.Cm passive +or +.Cm active +(as described above), +or whether the gateway is +.Cm external +to the scope of the RIP protocol. +.Pp +Lines that start with neither "net" nor "host" must consist of one +or more of the following parameter settings, separated by commas or +blanks: +.Bl -tag -width Ds +.It Cm if Ns \&= Ns Ar ifname +indicates that the other parameters on the line apply to the interface +name +.Ar ifname . +.It Cm subnet Ns \&= Ns Ar nname[/mask][,metric] +advertises a route to network +.AR nname +with mask +.AR mask +and the supplied metric (default 1). +This is useful for filling "holes" in CIDR allocations. +This parameter must appear by itself on a line. +.Pp +Do not use this feature unless necessary. It is dangerous. +.It Cm passwd Ns \&= Ns Ar XXX +specifies a RIPv2 password that will be included on all RIPv2 +responses sent and checked on all RIPv2 responses received. +The password must not contain any blanks, tab characters, commas +or '#' characters. +.It Cm no_ag +turns off aggregation of subnets in RIPv1 and RIPv2 responses. +.It Cm no_super_ag +turns off aggregation of networks into supernets in RIPv2 responses. +.It Cm passive +is equivalent +.Cm no_rip Cm no_rdisc . +.It Cm no_rip +disables all RIP processing on the specified interface. +If no interfaces are allowed to process RIP packets, +.Nm +acts purely as a router discovery daemon. +.Cm No_rip +is equivalent to +.Cm no_ripv1_in no_ripv2_in no_ripv1_out no_ripv2_out . + +Note that turning off RIP without explicitly turning on router +discovery advertisements with +.Cm rdisc_adv +or +.Fl s +causes +.Nm routed +to act as a client router discovery daemon, not adveritising. +.It Cm no_ripv1_in +causes RIPv1 received responses to be ignored. +.It Cm no_ripv2_in +causes RIPv2 received responses to be ignored. +.It Cm ripv2_out +turns off RIPv1 output and causes RIPv2 advertisements to be +multicast when possible. +.It Cm no_rdisc +disables the Internet Router Discovery Protocol. +.It Cm no_solicit +disables the tranmission of Router Discovery Solicitations. +.It Cm send_solicit +specifies that Router Discovery solicitations should be sent, +even on point-to-point links, +which by default only listen to Router Discovery messages. +.It Cm no_rdisc_adv +disables the transmission of Router Discovery Advertisements +.It Cm rdisc_adv +specifies that Router Discovery advertisements should be sent, +even on point-to-point links, +which by default only listen to Router Discovery messages +.It Cm bcast_rdisc +specifies that Router Discovery packets should be broadcast instead of +multicast. +.It Cm rdisc_pref Ns \&= Ns Ar N +sets the preference in Router Discovery Advertisements to the integer +.Ar N . +.It Cm rdisc_interval Ns \&= Ns Ar N +sets the nominal interval with which Router Discovery Advertisements +are transmitted to N seconds and their lifetime to 3*N. +.It Cm fake_default Ns \&= Ns Ar metric +has an identical effect to +.Fl F Ar net[/mask][,metric] +with the network and mask coming from the sepcified interface. +.It Cm pm_rdisc +is similar to +.Cm fake_default . +When RIPv2 routes are multicast, so that RIPv1 listeners cannot +receive them, this feature causes a RIPv1 default route to be +broadcast to RIPv1 listeners. +Unless modified with +.Cm fake_default , +the default route is broadcast with a metric of 14. +That serves as a "poor man's router discovery" protocol. +.El +.Pp +Note that the netmask associated with point-to-point links (such as SLIP +or PPP, with the IFF_POINTOPOINT flag) is used by +.Nm routed +to infer the netmask used by the remote system when RIPv1 is used. +.Pp +.Sh FILES +.Bl -tag -width /etc/gateways -compact +.It Pa /etc/gateways +for distant gateways +.El +.Sh SEE ALSO +.Xr gated 8 , +.Xr udp 4 , +.Xr icmp 4 , +.Xr htable 8 , +.Xr rtquery 8 . +.Rs +.%T Internet Transport Protocols +.%R XSIS 028112 +.%Q Xerox System Integration Standard +.Re +.Sh BUGS +It does not always detect unidirectional failures in network interfaces +(e.g., when the output side fails). +.Sh HISTORY +The +.Nm +command appeared in +.Bx 4.2 . |
