<author>
Ondrej Filip <it/<feela@network.cz>/,
Pavel Machek <it/<pavel@ucw.cz>/,
-Martin Mares <it/<mj@ucw.cz>/
+Martin Mares <it/<mj@ucw.cz>/,
+Ondrej Zajicek <it/<santiago@crfreenet.org>/
</author>
<abstract>
networks in order to allow hosts not connected directly to the same local area network to
communicate with each other. They also communicate with the other routers in the Internet to discover
the topology of the network which allows them to find optimal (in terms of some metric) rules for
-forwarding of packets (which will be called routes in the rest of this document) and to adapt themselves to the
+forwarding of packets (which are called routing tables) and to adapt themselves to the
changing conditions such as outages of network links, building of new connections and so on. Most of
these routers are costly dedicated devices running obscure firmware which is hard to configure and
not open to any changes (on the other hand, their special hardware design allows them to keep up with lots of high-speed network interfaces, better than general-purpose computer does). Fortunately, most operating systems of the UNIX family allow an ordinary
<p>A <em/Routing Daemon/ is in UNIX terminology a non-interactive program running on
background which does the dynamic part of Internet routing, that is it communicates
with the other routers, calculates routing tables and sends them to the OS kernel
-which does the actual packet forwarding. There already exist other such routing daemons: routed (rip only), GateD<HTMLURL URL="http://www.gated.org/">
- (non free), Zebra<HTMLURL URL="http://www.zebra.org"> and MRTD<HTMLURL URL="http://www.zcu.cz/ftp/mirrors/mmrz/mrtd">, but their capabilities are limited and
-they are relatively hard to configure and maintain.
+which does the actual packet forwarding. There already exist other such routing
+daemons: routed (RIP only), GateD (non-free), Zebra<HTMLURL URL="http://www.zebra.org">
+and MRTD<HTMLURL URL="http://sourceforge.net/projects/mrt">, but their capabilities are
+limited and they are relatively hard to configure and maintain.
<p>BIRD is an Internet Routing Daemon designed to avoid all of these shortcomings,
to support all the routing technology used in the today's Internet or planned to be
<item>both IPv4 and IPv6 protocols
<item>multiple routing tables
<item>the Border Gateway Protocol (BGPv4)
- <item>the Routing Interchange Protocol (RIPv2)
- <item>the Open Shortest Path First protocol (OSPFv2)
+ <item>the Routing Information Protocol (RIPv2)
+ <item>the Open Shortest Path First protocol (OSPFv2, OSPFv3)
<item>a virtual protocol for exchange of routes between different routing tables on a single host
<item>a command-line interface allowing on-line control and inspection
of status of the daemon
Public License.
<p>BIRD has been designed to work on all UNIX-like systems. It has been developed and
-tested under Linux 2.0 to 2.4, but porting to other systems (even non-UNIX ones) should
-be relatively easy due to its highly modular architecture.
+tested under Linux 2.0 to 2.6, and then ported to FreeBSD, NetBSD and OpenBSD, porting to other
+systems (even non-UNIX ones) should be relatively easy due to its highly modular architecture.
<sect>Installing BIRD
<descrip>
<tag>-c <m/config name/</tag>
- use given configuration file instead of <file>$prefix/etc/bird.conf</file>.
+ use given configuration file instead of <it/prefix/<file>/etc/bird.conf</file>.
<tag>-d</tag>
enable debug messages and run bird in foreground.
<tag>-D <m/filename of debug log/</tag>
- log debugging information to given file instead of stderr
+ log debugging information to given file instead of stderr.
+
+ <tag>-p</tag>
+ just parse the config file and exit. Return value is zero if the config file is valid,
+ nonzero if there are some errors.
<tag>-s <m/name of communication socket/</tag>
- use given filename for a socket for communications with the client, default is <file>$prefix/var/run/bird.ctl</file>.
+ use given filename for a socket for communications with the client, default is <it/prefix/<file>/var/run/bird.ctl</file>.
</descrip>
<p>BIRD writes messages about its work to log files or syslog (according to config).
<chapt>About routing tables
-<p>BIRD has one or more routing tables, which may or may not be
-synchronized with kernel and which may or may not be synchronized with
-each other (see the Pipe protocol). Each routing table contains list of
+<p>BIRD has one or more routing tables which may or may not be
+synchronized with OS kernel and which may or may not be synchronized with
+each other (see the Pipe protocol). Each routing table contains a list of
known routes. Each route consists of:
<itemize>
- <item>network prefix this route is for (consists of network address and number of bits forming the network part of the address)
- <item>preference of this route (taken from preference of
- protocol and possibly altered by filters)
- <item>IP address of router who told us about this route
+ <item>network prefix this route is for (network address and prefix length -- the number of bits forming the network part of the address; also known as a netmask)
+ <item>preference of this route
+ <item>IP address of router which told us about this route
<item>IP address of router we should forward the packets to
using this route
<item>other attributes common to all routes
may not be present (typically protocol metrics)
</itemize>
-Routing table maintains more than
-one entry for a network, but at most one entry for one network and one
-protocol. The entry with biggest preference is used for routing. If
+Routing table maintains multiple entries
+for a network, but at most one entry for one network and one
+protocol. The entry with the highest preference is used for routing (we
+will call such an entry the <it/selected route/). If
there are more entries with the same preference and they are from the same
-protocol, protocol decides (typically according to metrics). If not,
-internal ordering is used to decide. You can
-get list of route attributes in "Route attributes" section in
-filters.
-
-<p>Protocols are connected to routing tables through filters. Routes
-that come from other routers go to the protocol, it then passes them to
-filters, if import filter accepts route, it gets to main routing
-table. It is then broadcasted to all other protocols (filtered through
-their export filters), which typically send it to other routers.
-
-Filters can alter routes passed between routing tables and
-protocols.
+protocol, the protocol decides (typically according to metrics). If they aren't,
+an internal ordering is used to break the tie. You can
+get the list of route attributes in the Route attributes section.
+
+<p>Each protocol is connected to a routing table through two filters
+which can accept, reject and modify the routes. An <it/export/
+filter checks routes passed from the routing table to the protocol,
+an <it/import/ filter checks routes in the opposite direction.
+When the routing table gets a route from a protocol, it recalculates
+the selected route and broadcasts it to all protocols connected to
+the table. The protocols typically send the update to other routers
+in the network.
<chapt>Configuration
<sect>Introduction
-<p>BIRD is configured using a text configuration file. Upon startup, BIRD reads <file>$prefix/bird.conf</file> (unless the
-<tt/-c/ command line option is given). Configuration may be changed on user's request: if you modify
-config file and then signal BIRD with SIGHUP, it will adjust to the new
-config. Then there's the client,
-which allows you to talk with BIRD in an extensive way. (Of course you can tell BIRD to reconfigure from BIRDC, you can also tell it to shut down, dump various info etc.).
+<p>BIRD is configured using a text configuration file. Upon startup, BIRD reads <it/prefix/<file>/etc/bird.conf</file> (unless the
+<tt/-c/ command line option is given). Configuration may be changed at user's request: if you modify
+the config file and then signal BIRD with <tt/SIGHUP/, it will adjust to the new
+config. Then there's the client
+which allows you to talk with BIRD in an extensive way.
<p>In the config, everything on a line after <cf/#/ or inside <cf>/*
*/</cf> is a comment, whitespace characters are treated as a single space. If there's a variable number of options, they are grouped using
protocol rip {
export all;
import all;
+ interface "*";
}
</code>
<sect>Global options
<p><descrip>
- <tag>log "<m/filename/"|syslog|stderr all|{ <m/list of classes/ }</tag>
- Set logging of messages having the given (either <cf/all/ or <cf/{
- error, trace }/ etc.) into selected destination. Classes are:
- <cf/info/, <cf/warning/, <cf/error/ and <cf/fatal/ for messages about local problems
+ <tag>log "<m/filename/"|syslog [name <m/name/]|stderr all|{ <m/list of classes/ }</tag>
+ Set logging of messages having the given class (either <cf/all/ or <cf/{
+ error, trace }/ etc.) into selected destination (a file specified as a filename string,
+ syslog with optional name argument, or the stderr output). Classes are:
+ <cf/info/, <cf/warning/, <cf/error/ and <cf/fatal/ for messages about local problems,
<cf/debug/ for debugging messages,
<cf/trace/ when you want to know what happens in the network,
<cf/remote/ for messages about misbehavior of remote machines,
logging of connects and disconnects, 2 and higher for logging of
all client commands). Default: 0.
+ <tag>mrtdump "<m/filename/"</tag>
+ Set MRTdump file name. This option must be specified to allow MRTdump feature.
+ Default: no dump file.
+
+ <tag>mrtdump protocols all|off|{ states, messages }</tag>
+ Set global defaults of MRTdump options. See <cf/mrtdump/ in the following section.
+ Default: off.
+
<tag>filter <m/name local variables/{ <m/commands/ }</tag> Define a filter. You can learn more about filters
in the following chapter.
- <tag>function <m/name (parameters) local variables/ { <m/commands/ }</tag> Define a function. You can learn more
+ <tag>function <m/name/ (<m/parameters/) <m/local variables/ { <m/commands/ }</tag> Define a function. You can learn more
about functions in the following chapter.
<tag>protocol rip|ospf|bgp|... <m/[name]/ { <m>protocol options</m> }</tag> Define a protocol
- instance called <cf><m/name/</cf> (or with a name like "rip5" generated automatically, if you don't specify <cf><m/name/</cf>). You can learn more
+ instance called <cf><m/name/</cf> (or with a name like "rip5" generated automatically if you don't specify any <cf><m/name/</cf>). You can learn more
about configuring protocols in their own chapters. You can run more than one instance of
most protocols (like RIP or BGP). By default, no instances are configured.
<tag>define <m/constant/ = (<m/expression/)|<m/number/|<m/IP address/</tag> Define a constant. You can use it later in every place
- you could use a simple integer or IP address.
+ you could use a simple integer or an IP address.
<tag>router id <m/IPv4 address/</tag> Set BIRD's router ID. It's a world-wide unique identification of your router, usually one of router's IPv4 addresses. Default: in IPv4 version, the lowest IP address of a non-loopback interface. In IPv6 version, this option is mandatory.
+ <tag>listen bgp [address <m/address/] [port <m/port/] [v6only]</tag>
+ This option allows to specify address and port where BGP
+ protocol should listen. It is global option as listening
+ socket is common to all BGP instances. Default is to listen on
+ all addresses (0.0.0.0) and port 179. In IPv6 mode, option
+ <cf/v6only/ can be used to specify that BGP socket should
+ listen to IPv6 connections only. This is needed if you want to
+ run both bird and bird6 on the same port.
+
+ <tag>timeformat route|protocol|base|log "<m/format1/" [<m/limit> "<m/format2/"]</tag>
+ This option allows to specify a format of date/time used by
+ BIRD. The first argument specifies for which purpose such
+ format is used. <cf/route/ is a format used in 'show route'
+ command output, <cf/protocol/ is used in 'show protocols'
+ command output, <cf/base/ is used for other commands and
+ <cf/log/ is used in a log file.
+
+ "<m/format1/" is a format string using <i/strftime(3)/
+ notation (see <i/man strftime/ for details). <m/limit> and
+ "<m/format2/" allow to specify the second format string for
+ times in past deeper than <m/limit/ seconds. There are two
+ shorthands: <cf/iso long/ is a ISO 8601 date/time format
+ (YYYY-MM-DD hh:mm:ss) that can be also specified using <cf/"%F
+ %T"/. <cf/iso short/ is a variant of ISO 8601 that uses just
+ the time format (hh:mm:ss) for near times (up to 20 hours in
+ the past) and the date format (YYYY-MM-DD) for far times. This
+ is a shorthand for <cf/"%T" 72000 "%F"/.
+
+ By default, BIRD uses an short, ad-hoc format for <cf/route/
+ and <cf/protocol/ times, and a <cf/iso long/ similar format
+ (DD-MM-YYYY hh:mm:ss) for <cf/base/ and <cf/log/. These
+ defaults are here for a compatibility with older versions
+ and might change in the future.
+
<tag>table <m/name/</tag> Create a new routing table. The default
routing table is created implicitly, other routing tables have
to be added by this command.
<tag>eval <m/expr/</tag> Evaluates given filter expression. It
- is used by us for testing filters.
+ is used by us for testing of filters.
</descrip>
<sect>Protocol options
<cf/events/ for events internal to the protocol and
<cf/packets/ for packets sent and received by the protocol. Default: off.
+ <tag>mrtdump all|off|{ states, messages }</tag>
+
+ Set protocol MRTdump flags. MRTdump is a standard binary
+ format for logging information from routing protocols and
+ daemons. These flags control what kind of information is
+ logged from the protocol to the MRTdump file (which must be
+ specified by global <cf/mrtdump/ option, see the previous
+ section). Although these flags are similar to flags of
+ <cf/debug/ option, their meaning is different and
+ protocol-specific. For BGP protocol, <cf/states/ logs BGP
+ state changes and <cf/messages/ logs received BGP messages.
+ Other protocols does not support MRTdump yet.
+
+ <tag>router id <m/IPv4 address/</tag> This option can be used
+ to override global router id for a given protocol. Default:
+ uses global router id.
+
<tag>import all | none | filter <m/name/ | filter { <m/filter commands/ } | where <m/filter expression/</tag>
- Specify a filter to be used for filtering routes coming from protocol to the routing table. <cf/all/ is shorthand for <cf/where true/ and <cf/none/ is shorthand for <cf/where false/. Default: <cf/all/.
+ Specify a filter to be used for filtering routes coming from the protocol to the routing table. <cf/all/ is shorthand for <cf/where true/ and <cf/none/ is shorthand for <cf/where false/. Default: <cf/all/.
+
+ <tag>export <m/filter/</tag> This is similar to the <cf>import</cf> keyword, except that it
+ works in the direction from the routing table to the protocol. Default: <cf/none/.
- <tag>export <m/filter/</tag> This is similar to <cf>import</cf> keyword, except that it
- works in direction from the routing table to the protocol. Default: <cf/none/.
+ <tag>description "<m/text/"</tag> This is an optional
+ description of the protocol. It is displayed as a part of the
+ output of 'show route all' command.
<tag>table <m/name/</tag> Connect this protocol to a non-default routing table.
</descrip>
<p>There are several options that give sense only with certain protocols:
<descrip>
- <tag>passwords { password "<m/password/" from <m/time/ to <m/time/ passive <m/time/ id
- <m/num/ [...] }</tag> Specifies passwords to be used with this protocol. <cf>Passive <m/time/</cf> is
- time from which the password is not used for sending, but it is recognized on reception. <cf/id/ is password ID, as needed by
- certain protocols. Format of <cf><m/time/</cf> is <tt>dd-mm-yyyy HH:MM:SS</tt>.
-
- <tag>interface "<m/mask/"|<m/prefix/ [ { <m/option/ ; [ ... ] } ]</tag> Specifies which
- interfaces this protocol is active on, and allows you to set options on
- per-interface basis. Mask is specified in shell-like patterns, thus <cf>interface
- "*" { mode broadcast; };</cf> will start the protocol on all interfaces with <cf>mode
- broadcast;</cf> option. If first character of mask is <cf/-/, such interfaces are
- excluded. Masks are parsed left-to-right, thus <cf/interface "-eth*", "*";/ means all but
- the ethernets. Default: none.
+ <tag><label id="dsc-iface">interface [-] [ "<m/mask/" ] [ <m/prefix/ ] [, ...] [ { <m/option/ ; [...] } ]</tag>
+
+ Specifies a set of interfaces on which the protocol is activated with
+ given interface-specific options. A set of interfaces specified by one
+ interface option is described using an interface pattern. The
+ interface pattern consists of a sequence of clauses (separated by
+ commas), each clause may contain a mask, a prefix, or both of them. An
+ interface matches the clause if its name matches the mask (if
+ specified) and its address matches the prefix (if specified). Mask is
+ specified as shell-like pattern.
+
+ An interface matches the pattern if it matches any of its
+ clauses. If the clause begins with <cf/-/, matching interfaces are
+ excluded. Patterns are parsed left-to-right, thus
+ <cf/interface "eth0", -"eth*", "*";/ means eth0 and all
+ non-ethernets.
+
+ An interface option can be used more times with different
+ interfaces-specific options, in that case for given interface
+ the first matching interface option is used.
+
+ This option is allowed in Direct, OSPF and RIP protocols,
+ but in OSPF protocol it is used in <cf/area/ subsection.
+
+ Default: none.
+
+ Examples:
+
+ <cf>interface "*" { type broadcast; };</cf> - start the protocol on all interfaces with
+ <cf>type broadcast</cf> option.
+
+ <cf>interface "eth1", "eth4", "eth5" { type pointopoint; };</cf> - start the protocol
+ on enumerated interfaces with <cf>type pointopoint</cf> option.
+
+ <cf>interface -192.168.1.0/24, 192.168.0.0/16;</cf> - start the protocol on all
+ interfaces that have address from 192.168.0.0/16, but not
+ from 192.168.1.0/24.
+
+ <cf>interface -192.168.1.0/24, 192.168.0.0/16;</cf> - start the protocol on all
+ interfaces that have address from 192.168.0.0/16, but not
+ from 192.168.1.0/24.
+
+ <cf>interface "eth*" 192.168.1.0/24;</cf> - start the protocol on all
+ ethernet interfaces that have address from 192.168.1.0/24.
+
+ <tag><label id="dsc-pass">password "<m/password/" [ { id <m/num/; generate from <m/time/; generate to <m/time/; accept from <m/time/; accept to <m/time/; } ]</tag>
+ Specifies a password that can be used by the protocol. Password option can
+ be used more times to specify more passwords. If more passwords are
+ specified, it is a protocol-dependent decision which one is really
+ used. Specifying passwords does not mean that authentication is
+ enabled, authentication can be enabled by separate, protocol-dependent
+ <cf/authentication/ option.
+
+ This option is allowed in OSPF and RIP protocols. BGP has also
+ <cf/password/ option, but it is slightly different and described
+ separately.
+
+ Default: none.
+</descrip>
+
+<p>Password option can contain section with some (not necessary all) password sub-options:
+
+<descrip>
+ <tag>id <M>num</M></tag>
+ ID of the password, (0-255). If it's not used, BIRD will choose
+ ID based on an order of the password item in the interface. For
+ example, second password item in one interface will have default
+ ID 2. ID is used by some routing protocols to identify which
+ password was used to authenticate protocol packets.
+
+ <tag>generate from "<m/time/"</tag>
+ The start time of the usage of the password for packet signing.
+ The format of <cf><m/time/</cf> is <tt>dd-mm-yyyy HH:MM:SS</tt>.
+ <tag>generate to "<m/time/"</tag>
+ The last time of the usage of the password for packet signing.
+
+ <tag>accept from "<m/time/"</tag>
+ The start time of the usage of the password for packet verification.
+
+ <tag>accept to "<m/time/"</tag>
+ The last time of the usage of the password for packet verification.
</descrip>
<chapt>Remote control
<p>You can use the command-line client <file>birdc</file> to talk with
-a running BIRD. Communication is done using <file/bird.ctl/ UNIX domain
-socket (unless changed with the <tt/-s/ option given to both the server and
-the client). The client can do simple actions such as enabling/disabling
-protocols, telling BIRD to show various information, telling it to
-show routing table filtered by any filter, or telling bird to
-reconfigure. Press <tt/?/ at any time to get online help. Option
-<tt/-v/ can be passed to the client, telling it to dump numeric return
-codes. You do not necessarily need to use BIRDC to talk to BIRD, your
-own application could do that, too -- format of communication between
-BIRD and BIRDC is stable (see programmer's documentation).
+a running BIRD. Communication is done using a <file/bird.ctl/ UNIX
+domain socket (unless changed with the <tt/-s/ option given to both
+the server and the client). The commands can perform simple actions
+such as enabling/disabling of protocols, telling BIRD to show various
+information, telling it to show routing table filtered by filter, or
+asking BIRD to reconfigure. Press <tt/?/ at any time to get online
+help. Option <tt/-r/ can be used to enable a restricted mode of BIRD
+client, which allows just read-only commands (<cf/show .../). Option
+<tt/-v/ can be passed to the client, to make it dump numeric return
+codes along with the messages. You do not necessarily need to use
+<file/birdc/ to talk to BIRD, your own applications could do that, too
+-- the format of communication between BIRD and <file/birdc/ is stable
+(see the programmer's documentation).
+
+Many commands have the <m/name/ of the protocol instance as an argument.
+This argument can be omitted if there exists only a single instance.
<p>Here is a brief list of supported functions:
Dump contents of internal data structures to the debugging output.
<tag>show status</tag>
- Show router status, that is bird version, uptime and time from last reconfiguration.
+ Show router status, that is BIRD version, uptime and time from last reconfiguration.
<tag>show protocols [all]</tag>
- Show list of protocols along with tables they are connected to and status, possibly giving verbose information.
+ Show list of protocol instances along with tables they are connected to and protocol status, possibly giving verbose information, if <cf/all/ is specified.
+
+ <tag>show ospf interface [<m/name/] ["<m/interface/"]</tag>
+ Show detailed information about OSPF interfaces.
- <tag>show ospf [interface|neighbors] [<m/name/] ["<m/interface/"]</tag>
- Show detailed information about OSPF protocol, possibly giving a verbose list of interfaces and neighbors. The <m/name/ of the protocol instance can be omitted if there exists only a single instance.
+ <tag>show ospf neighbors [<m/name/] ["<m/interface/"]</tag>
+ Show a list of OSPF neighbors and a state of adjacency to them.
+
+ <tag>show ospf state [<m/name/]</tag>
+ Show detailed information about OSPF areas based on a content of link-state database.
+ It shows network topology, aggregated networks and routers from other areas and external routes.
+
+ <tag>show ospf topology [<m/name/]</tag>
+ Show a topology of OSPF areas based on a content of link-state database.
+ It is just a stripped-down version of 'show ospf state'.
<tag>show static [<m/name/]</tag>
- Show detailed information about static routes. The <m/name/ of the protocol instance can be omitted if there exists only a single instance.
-
+ Show detailed information about static routes.
+
<tag>show interfaces [summary]</tag>
- Show list of interfaces. For each interface, print its type, state, MTU and addresses assigned.
+ Show the list of interfaces. For each interface, print its type, state, MTU and addresses assigned.
<tag>show symbols</tag>
- Show list of symbols defined in the configuration (names of protocols, routing tables etc.).
+ Show the list of symbols defined in the configuration (names of protocols, routing tables etc.).
- <tag>show route [<m/prefix/|for <m/prefix or IP/] [primary] [table <m/sym/] [all] [stats|count] [filter <m/name/|where <m/condition/] [(import|proto) <m/sym/]</tag>
+ <tag>show route [[for] <m/prefix/|<m/IP/] [table <m/sym/] [filter <m/f/|where <m/c/] [(export|preexport) <m/p/] [protocol <m/p/] [<m/options/]</tag>
Show contents of a routing table (by default of the main one),
- i.e. routes, their metrics and (in case the <cf/all/ switch is given)
+ that is routes, their metrics and (in case the <cf/all/ switch is given)
all their attributes.
<p>You can specify a <m/prefix/ if you want to print routes for a
<p>You can also ask for printing only routes processed and accepted by
a given filter (<cf>filter <m/name/</cf> or <cf>filter { <m/filter/ }
</cf> or matching a given condition (<cf>where <m/condition/</cf>).
- The <cf/import/ and <cf/proto/ switches ask for printing of entries as
- they would be seen by the specified protocol. With <cf/import/, the
+ The <cf/export/ and <cf/preexport/ switches ask for printing of entries
+ that are exported to the specified protocol. With <cf/preexport/, the
export filter of the protocol is skipped.
+ <p>You can also select just routes added by a specific protocol.
+ <cf>protocol <m/p/</cf>.
+
<p>The <cf/stats/ switch requests showing of route statistics (the
number of networks, number of routes before and after filtering). If
you use <cf/count/ instead, only the statistics will be printed.
+ <tag>configure [soft] ["<m/config file/"]</tag>
+ Reload configuration from a given file. BIRD will smoothly
+ switch itself to the new configuration, protocols are
+ reconfigured if possible, restarted otherwise. Changes in
+ filters usually lead to restart of affected protocols. If
+ <cf/soft/ option is used, changes in filters does not cause
+ BIRD to restart affected protocols, therefore already accepted
+ routes (according to old filters) would be still propagated,
+ but new routes would be processed according to the new
+ filters.
+
<tag>enable|disable|restart <m/name/|"<m/pattern/"|all</tag>
- Enable, disable or restart given protocol instance, instances matching the <cf><m/pattern/</cf> or <cf/all/ instances.
+ Enable, disable or restart a given protocol instance, instances matching the <cf><m/pattern/</cf> or <cf/all/ instances.
- <tag>configure ["<m/config file/"]</tag>
- Reload configuration from a given file.
+ <tag>reload [in|out] <m/name/|"<m/pattern/"|all</tag>
+
+ Reload a given protocol instance, that means re-import routes
+ from the protocol instance and re-export preferred routes to
+ the instance. If <cf/in/ or <cf/out/ options are used, the
+ command is restricted to one direction (re-import or
+ re-export).
+
+ This command is useful if appropriate filters have changed but
+ the protocol instance was not restarted (or reloaded),
+ therefore it still propagates the old set of routes. For example
+ when <cf/configure soft/ command was used to change filters.
+
+ Re-export always succeeds, but re-import is protocol-dependent
+ and might fail (for example, if BGP neighbor does not support
+ route-refresh extension). In that case, re-export is also
+ skipped. Note that for the pipe protocol, both directions are
+ always reloaded together (<cf/in/ or <cf/out/ options are
+ ignored in that case).
<tag/down/
Shut BIRD down.
<sect>Introduction
-<p>BIRD contains a rather simple programming language. (No, it can't yet read mail :-). There are
-two objects in this language: filters and functions. Filters are called by BIRD core when a route is
-being passed between protocols and routing tables. Filter language contains control structures such
-as if's and switches, but it allows no loops. Filters are
-interpreted. An example of a filter using many features can be found in <file>filter/test.conf</file>.
+<p>BIRD contains a simple programming language. (No, it can't yet read mail :-). There are
+two objects in this language: filters and functions. Filters are interpreted by BIRD core when a route is
+being passed between protocols and routing tables. The filter language contains control structures such
+as if's and switches, but it allows no loops. An example of a filter using many features can be found in <file>filter/test.conf</file>.
<p>Filter gets the route, looks at its attributes and
modifies some of them if it wishes. At the end, it decides whether to
-pass the changed route through (using <cf/accept/) or whether to <cf/reject/ given route. A simple filter looks
+pass the changed route through (using <cf/accept/) or whether to <cf/reject/ it. A simple filter looks
like this:
<code>
</code>
<p>As you can see, a filter has a header, a list of local variables, and a body. The header consists of
-the <cf/filter/ keyword, followed by a (unique) name of filter. List of local variables consists of
-pairs <cf><M>type name</M>;</cf>, where each pair defines one local variable. Body consists of
-<cf> { <M>statements</M> }</cf>. Each <m/statement/ is terminated by <cf/;/. You can group
-several statements into one by using braces (<cf>{ <M>statements</M> }</cf>), that is useful if
-you want to make bigger block of code conditional.
-
-<p>BIRD supports functions, so that you don't have to repeat same blocks of code over and
-over. Functions can have zero or more parameters and they can have local variables. Recursion is not allowed. They
+the <cf/filter/ keyword followed by a (unique) name of filter. The list of local variables consists of
+<cf><M>type name</M>;</cf> pairs where each pair defines one local variable. The body consists of
+<cf> { <M>statements</M> }</cf>. Each <m/statement/ is terminated by a <cf/;/. You can group
+several statements to a single compound statement by using braces (<cf>{ <M>statements</M> }</cf>) which is useful if
+you want to make a bigger block of code conditional.
+
+<p>BIRD supports functions, so that you don't have to repeat the same blocks of code over and
+over. Functions can have zero or more parameters and they can have local variables. Recursion is not allowed. Function definitions
look like this:
<code>
}
</code>
-<p>Unlike in C, variables are declared after function line but before the first {. You can't declare
+<p>Unlike in C, variables are declared after the <cf/function/ line, but before the first <cf/{/. You can't declare
variables in nested blocks. Functions are called like in C: <cf>name();
-with_parameters(5);</cf>. Function may return value using the <cf>return <m/[expr]/</cf>
+with_parameters(5);</cf>. Function may return values using the <cf>return <m/[expr]/</cf>
command. Returning a value exits from current function (this is similar to C).
<p>Filters are declared in a way similar to functions except they can't have explicit
-parameters. They get route table entry as an implicit parameter, it is also passed automatically
+parameters. They get a route table entry as an implicit parameter, it is also passed automatically
to any functions called. The filter must terminate with either
-<cf/accept/ or <cf/reject/ statement. If there's runtime error in filter, the route
+<cf/accept/ or <cf/reject/ statement. If there's a runtime error in filter, the route
is rejected.
<p>A nice trick to debug filters is to use <cf>show route filter
195.113.30.2/32 dev tunl1 [direct1 23:21] (240)
127.0.0.0/8 dev lo [direct1 23:21] (240)
bird> show route ?
-show route [<prefix>] [table <t>] [filter <f>] [all] [primary] [(import|protocol) <p>]...
-bird> show route filter { if 127.0.0.5 ~ net then accept; }
+show route [<prefix>] [table <t>] [filter <f>] [all] [primary]...
+bird> show route filter { if 127.0.0.5 ˜ net then accept; }
127.0.0.0/8 dev lo [direct1 23:21] (240)
bird>
</code>
<descrip>
<tag/bool/ This is a boolean type, it can have only two values, <cf/true/ and
- <cf/false/. Boolean is not compatible with integer and is the only type you can use in if
+ <cf/false/. Boolean is the only type you can use in <cf/if/
statements.
<tag/int/ This is a general integer type, you can expect it to store signed values from -2000000000
to +2000000000. Overflows are not checked. You can use <cf/0x1234/ syntax to write hexadecimal values.
<tag/pair/ This is a pair of two short integers. Each component can have values from 0 to
- 65535. Literals of this type is written as <cf/(1234,5678)/.
+ 65535. Literals of this type are written as <cf/(1234,5678)/. The same syntax can also be
+ used to construct a pair from two arbitrary integer expressions (for example <cf/(1+2,a)/).
+
+ <tag/quad/ This is a dotted quad of numbers used to represent
+ router IDs (and others). Each component can have a value
+ from 0 to 255. Literals of this type are written like IPv4
+ addresses.
<tag/string/ This is a string of characters. There are no ways to modify strings in
filters. You can pass them between functions, assign them to variables of type <cf/string/, print
<tag/ip/ This type can hold a single IP address. Depending on the compile-time configuration of BIRD you are using, it
is either an IPv4 or IPv6 address. IP addresses are written in the standard notation (<cf/10.20.30.40/ or <cf/fec0:3:4::1/). You can apply special operator <cf>.mask(<M>num</M>)</cf>
- on values of type ip. It masks out all but first <cf><M>num</M></cf> bits from ip
+ on values of type ip. It masks out all but first <cf><M>num</M></cf> bits from the IP
address. So <cf/1.2.3.4.mask(8) = 1.0.0.0/ is true.
<tag/prefix/ This type can hold a network prefix consisting of IP address and prefix length. Prefix literals are written as
<cf><M>ipaddress</M>/<M>pxlen</M></cf>, or
- <cf><m>ipaddress</m>/<m>netmask</m></cf> There are two special
- operators on prefix:
- <cf/.ip/, which separates ip address from the pair, and <cf/.len/, which separates prefix
- len from the pair. So <cf>1.2.0.0/16.pxlen = 16</cf> is true.
+ <cf><m>ipaddress</m>/<m>netmask</m></cf>. There are two special
+ operators on prefixes:
+ <cf/.ip/ which extracts the IP address from the pair, and <cf/.len/, which separates prefix
+ length from the pair. So <cf>1.2.0.0/16.pxlen = 16</cf> is true.
- <tag/int|ip|prefix|pair|enum set/
+ <tag/int|pair|quad|ip|prefix|enum set/
Filters recognize four types of sets. Sets are similar to strings: you can pass them around
- but you can't modify them. Literals of type <cf>set int</cf> look like <cf>
+ but you can't modify them. Literals of type <cf>int set</cf> look like <cf>
[ 1, 2, 5..7 ]</cf>. As you can see, both simple values and ranges are permitted in
- sets. Sets of prefixes are special: you can specify which prefix lengths should match them by
- using <cf>[ 1.0.0.0/8+, 2.0.0.0/8-, 3.0.0.0/8{5,6} ]</cf>. <cf>3.0.0.0/8{5,6}</cf> matches
- prefixes <cf/3.X.X.X/, whose prefix length is 5 to 6. <cf><m>address</m>/<m>num</m>+</cf> is shorthand for <cf><m>address</m>/{0,<m/num/}</cf>,
- <cf><m>address</m>/<m/num/-</cf> is shorthand for <cf><m>address</m>/{0,<m/num-1/}</cf>. For example,
- <cf>1.2.0.0/16 ~ [ 1.0.0.0/8{ 15 , 17 } ]</cf> is true, but
- <cf>1.0.0.0/8 ~ [ 1.0.0.0/8- ]</cf> is false.
+ sets.
+
+ Sets of prefixes are special: their literals does not allow ranges, but allows
+ prefix patterns that are written as <cf><M>ipaddress</M>/<M>pxlen</M>{<M>low</M>,<M>high</M>}</cf>.
+ Prefix <cf><m>ip1</m>/<m>len1</m></cf> matches prefix pattern <cf><m>ip2</m>/<m>len2</m>{<m>l</m>,<m>h</m>}</cf> iff
+ the first <cf>min(len1, len2)</cf> bits of <cf/ip1/ and <cf/ip2/ are identical and <cf>len1 <= ip1 <= len2</cf>.
+ A valid prefix pattern has to satisfy <cf>low <= high</cf>, but <cf/pxlen/ is not constrained by <cf/low/
+ or <cf/high/. Obviously, a prefix matches a prefix set literal iff it matches any prefix pattern in the
+ prefix set literal.
+
+ There are also two shorthands for prefix patterns: <cf><m>address</m>/<m/len/+</cf> is a shorthand for
+ <cf><m>address</m>/<m/len/{<m/len/,<m/maxlen/}</cf> (where <cf><m>maxlen</m></cf> is 32 for IPv4 and 128 for IPv6),
+ that means network prefix <cf><m>address</m>/<m/len/</cf> and all its subnets. <cf><m>address</m>/<m/len/-</cf>
+ is a shorthand for <cf><m>address</m>/<m/len/{0,<m/len/}</cf>, that means network prefix <cf><m>address</m>/<m/len/</cf>
+ and all its supernets (network prefixes that contain it).
+
+ For example, <cf>[ 1.0.0.0/8, 2.0.0.0/8+, 3.0.0.0/8-, 4.0.0.0/8{16,24} ]</cf> matches
+ prefix <cf>1.0.0.0/8</cf>, all subprefixes of <cf>2.0.0.0/8</cf>, all superprefixes of <cf>3.0.0.0/8</cf> and prefixes
+ <cf/4.X.X.X/ whose prefix length is 16 to 24. <cf>[ 0.0.0.0/0{20,24} ]</cf> matches all prefixes (regardless of
+ IP address) whose prefix length is 20 to 24, <cf>[ 1.2.3.4/32- ]</cf> matches any prefix that contains IP address
+ <cf>1.2.3.4</cf>. <cf>1.2.0.0/16 ˜ [ 1.0.0.0/8{15,17} ]</cf> is true,
+ but <cf>1.0.0.0/16 ˜ [ 1.0.0.0/8- ]</cf> is false.
+
+ Cisco-style patterns like <cf>10.0.0.0/8 ge 16 le 24</cf> can be expressed
+ in BIRD as <cf>10.0.0.0/8{16,24}</cf>, <cf>192.168.0.0/16 le 24</cf> as
+ <cf>192.168.0.0/16{16,24}</cf> and <cf>192.168.0.0/16 ge 24</cf> as
+ <cf>192.168.0.0/16{24,32}</cf>.
<tag/enum/
- Enumeration types are fixed in BIRD -- you can't define your own
- variables of enumeration type, but some route attributes are of enumeration
+ Enumeration types are fixed sets of possibilities. You can't define your own
+ variables of such type, but some route attributes are of enumeration
type. Enumeration types are incompatible with each other.
<tag/bgppath/
BGP path is a list of autonomous system numbers. You can't write literals of this type.
+ There are several special operators on bgppaths:
+
+ <cf><m/P/.first</cf> returns the first ASN (the neighbor ASN) in path <m/P/.
+
+ <cf><m/P/.last</cf> returns the last ASN (the source ASN) in path <m/P/.
+
+ Both <cf/first/ and <cf/last/ return zero if there is no appropriate ASN,
+ for example if the path contains an AS set element as the first (or the last) part.
+
+ <cf><m/P/.len</cf> returns the length of path <m/P/.
+
+ <cf>prepend(<m/P/,<m/A/)</cf> prepends ASN <m/A/ to path <m/P/ and returns the result.
+ Statement <cf><m/P/ = prepend(<m/P/, <m/A/);</cf> can be shortened to
+ <cf><m/P/.prepend(<m/A/);</cf> if <m/P/ is appropriate route attribute
+ (for example <cf/bgp_path/).
<tag/bgpmask/
BGP masks are patterns used for BGP path matching
- (using <cf>path ˜ /2 3 5 ?/</cf> syntax). The masks
+ (using <cf>path ˜ [= 2 3 5 * =]</cf> syntax). The masks
resemble wildcard patterns as used by UNIX shells. Autonomous
- system numbers match themselves, <cf/?/ matches any (even empty)
- sequence of arbitrary AS numbers (<cf/*/ hasn't been chosen, because
- <cf>/*</cf> starts a comment). For example:
- <tt>/4 3 2 1/ ~ /? 4 3 ?/</tt> is true, but
- <tt>/4 3 2 1/ ~ /? 4 5 ?/</tt> is false.
- <tag/clist/
- Community list is similar to set of pairs,
- except that unlike other sets, it can be modified.
- There exist no literals of this type.
+ system numbers match themselves, <cf/*/ matches any (even empty)
+ sequence of arbitrary AS numbers and <cf/?/ matches one arbitrary AS number.
+ For example, if <cf>bgp_path</cf> is 4 3 2 1, then:
+ <tt>bgp_path ˜ [= * 4 3 * =]</tt> is true, but
+ <tt>bgp_path ˜ [= * 4 5 * =]</tt> is false.
+ BGP mask expressions can also contain integer expressions enclosed in parenthesis
+ and integer variables, for example <tt>[= * 4 (1+2) a =]</tt>.
+ There is also old syntax that uses / .. / instead of [= .. =] and ? instead of *.
+
+ <tag/clist/
+ Clist is similar to a set, except that unlike other sets, it
+ can be modified. The type is used for community list (a set
+ of pairs) and for cluster list (a set of quads). There exist
+ no literals of this type. There are two special operators on
+ clists:
+
+ <cf>add(<m/C/,<m/P/)</cf> adds pair (or quad) <m/P/ to clist <m/C/ and returns the result.
+
+ <cf>delete(<m/C/,<m/P/)</cf> deletes pair (or quad) <m/P/ from clist <m/C/ and returns the result.
+
+ Statement <cf><m/C/ = add(<m/C/, <m/P/);</cf> can be shortened to
+ <cf><m/C/.add(<m/P/);</cf> if <m/C/ is appropriate route attribute
+ (for example <cf/bgp_community/). Similarly for <cf/delete/.
</descrip>
<sect>Operators
-<!-- Sorry, birddoc does not support tables. -->
-
<p>The filter language supports common integer operators <cf>(+,-,*,/)</cf>, parentheses <cf/(a*(b+c))/, comparison
-<cf/(a=b, a!=b, a<b, a>=b)/. Logical operations include unary not (<cf/!/), and (<cf/&&/) and or (<cf/||/).
-Special operators include <cf/˜/ for "in" operation. In operation can be
-used on element and set of that elements (returning true if element is within given set), or on IP and prefix (returning true if IP is within range defined by that prefix), or on
-prefix and prefix (returning true if first prefix is more specific than second) or on bgppath and bgpmask (returning true if path matches given path mask) or on pair and clist (returning true if given community is element of community list).
+<cf/(a=b, a!=b, a<b, a>=b)/. Logical operations include unary not (<cf/!/), and (<cf/&&/) and or (<cf/||/).
+Special operators include <cf/˜/ for "is element of a set" operation - it can be
+used on element and set of elements of the same type (returning true if element is contained in the given set), or
+on two strings (returning true if first string matches a shell-like pattern stored in second string) or on IP and prefix (returning true if IP is within the range defined by that prefix), or on
+prefix and prefix (returning true if first prefix is more specific than second one) or on bgppath and bgpmask (returning true if the path matches the mask) or on pair and clist (returning true if the pair (or quad) is element of the clist).
<sect>Control structures
<p>Filters support two control structures: conditions and case switches.
-<p>Syntax of condition is <cf>if
+<p>Syntax of a condition is: <cf>if
<M>boolean expression</M> then <M>command1</M>; else <M>command2</M>;</cf> and you can use <cf>{
-<M>command_1</M>; <M>command_2</M>; <M>...</M> }</cf> instead of one or both commands. <cf>else</cf>
-clause may be omitted. If <cf><m>boolean expression</m></cf> is true, <cf><m>command1</m></cf> is executed, otherwise <cf><m>command2</m></cf> is executed.
+<M>command_1</M>; <M>command_2</M>; <M>...</M> }</cf> instead of either command. The <cf>else</cf>
+clause may be omitted. If the <cf><m>boolean expression</m></cf> is true, <cf><m>command1</m></cf> is executed, otherwise <cf><m>command2</m></cf> is executed.
-<p><cf>case</cf> is similar to case from Pascal. Syntax is <cf>case <m/expr/ { else |
-<m/num_or_prefix [ .. num_or_prefix]/: <m/statement/ ; [ ... ] }</cf>. Expression after
-<cf>case</cf> can be of any type that can be on the left side of the ˜ operator, and anything that could
-be a member of a set is allowed before <cf/:/. Multiple commands are allowed without <cf/{}/ grouping
-and break is implicit before each case. If <cf><m/expr/</cf> matches one of <cf/:/ clauses, statements between it and next <cf/:/ statement are executed. If <cf><m/expr/</cf> matches neither of <cf/:/ clauses, <cf/else:/ statements after <cf/else:/ are executed.
+<p>The <cf>case</cf> is similar to case from Pascal. Syntax is <cf>case <m/expr/ { else |
+<m/num_or_prefix [ .. num_or_prefix]/: <m/statement/ ; [ ... ] }</cf>. The expression after
+<cf>case</cf> can be of any type which can be on the left side of the ˜ operator and anything that could
+be a member of a set is allowed before <cf/:/. Multiple commands are allowed without <cf/{}/ grouping.
+If <cf><m/expr/</cf> matches one of the <cf/:/ clauses, statements between it and next <cf/:/ statement are executed. If <cf><m/expr/</cf> matches neither of the <cf/:/ clauses, the statements after <cf/else:/ are executed.
<p>Here is example that uses <cf/if/ and <cf/case/ structures:
<sect>Route attributes
-<p>An filter is implicitly passed route, and it can access its
-attributes just like it accesses variables. Attempt to access undefined
+<p>A filter is implicitly passed a route, and it can access its
+attributes just like it accesses variables. Attempts to access undefined
attribute result in a runtime error; you can check if an attribute is
-defined using the <cf>defined( <m>attribute</m> )</cf> operator.
+defined by using the <cf>defined( <m>attribute</m> )</cf> operator.
+One notable exception to this rule are attributes of clist type, where
+undefined value is regarded as empty clist for most purposes.
<descrip>
<tag><m/prefix/ net</tag>
- Network the route is talking about. Read-only. (See the section about routing tables.)
+ Network the route is talking about. Read-only. (See the chapter about routing tables.)
<tag><m/enum/ scope</tag>
- Address scope of the network (<cf/SCOPE_HOST/ for addresses local to this host, <cf/SCOPE_LINK/ for those specific for a physical link, <cf/SCOPE_SITE/ and <cf/SCOPE_ORGANIZATION/ for private addresses, <cf/SCOPE_UNIVERSE/ for globally visible addresses).
+ The scope of the route. Possible values: <cf/SCOPE_HOST/ for
+ routes local to this host, <cf/SCOPE_LINK/ for those specific
+ for a physical link, <cf/SCOPE_SITE/ and
+ <cf/SCOPE_ORGANIZATION/ for private routes and
+ <cf/SCOPE_UNIVERSE/ for globally visible routes. This
+ attribute is not interpreted by BIRD and can be used to mark
+ routes in filters. The default value for new routes is
+ <cf/SCOPE_UNIVERSE/.
<tag><m/int/ preference</tag>
- Preference of the route. (See section about routing tables.)
+ Preference of the route. Valid values are 0-65535. (See the chapter about routing tables.)
<tag><m/ip/ from</tag>
The router which the route has originated from. Read-only.
<tag><m/ip/ gw</tag>
Next hop packets routed using this route should be forwarded to.
+ <tag><m/string/ proto</tag>
+ The name of the protocol which the route has been imported from. Read-only.
+
<tag><m/enum/ source</tag>
- what protocol has told me about this route. Possible values: <cf/RTS_DUMMY, RTS_STATIC, RTS_INHERIT, RTS_DEVICE, RTS_STATIC_DEVICE, RTS_REDIRECT, RTS_RIP, RTS_OSPF, RTS_OSPF_EXT, RTS_OSPF_IA, RTS_OSPF_BOUNDARY, RTS_BGP, RTS_PIPE/.
+ what protocol has told me about this route. Possible values: <cf/RTS_DUMMY/, <cf/RTS_STATIC/, <cf/RTS_INHERIT/, <cf/RTS_DEVICE/, <cf/RTS_STATIC_DEVICE/, <cf/RTS_REDIRECT/, <cf/RTS_RIP/, <cf/RTS_OSPF/, <cf/RTS_OSPF_IA/, <cf/RTS_OSPF_EXT/, <cf/RTS_BGP/, <cf/RTS_PIPE/.
<tag><m/enum/ cast</tag>
- Route type (<cf/RTC_UNICAST/ for normal routes, <cf/RTC_BROADCAST, RTC_MULTICAST, RTC_ANYCAST/ for broadcast, multicast and anycast routes). Read-only.
+
+ Route type (Currently <cf/RTC_UNICAST/ for normal routes,
+ <cf/RTC_BROADCAST/, <cf/RTC_MULTICAST/, <cf/RTC_ANYCAST/ will
+ be used in the future for broadcast, multicast and anycast
+ routes). Read-only.
<tag><m/enum/ dest</tag>
- Type of destination the packets should be sent to (<cf/RTD_ROUTER/ for forwarding to a neighboring router, <cf/RTD_NETWORK/ for routing to a directly-connected network, <cf/RTD_BLACKHOLE/ for packets to be silently discarded, <cf/RTD_UNREACHABLE/, <cf/RTD_PROHIBIT/ for packets that should be returned with ICMP host unreachable / ICMP administratively prohibited messages). Read-only.
+ Type of destination the packets should be sent to (<cf/RTD_ROUTER/ for forwarding to a neighboring router, <cf/RTD_DEVICE/ for routing to a directly-connected network, <cf/RTD_BLACKHOLE/ for packets to be silently discarded, <cf/RTD_UNREACHABLE/, <cf/RTD_PROHIBIT/ for packets that should be returned with ICMP host unreachable / ICMP administratively prohibited messages). Read-only.
</descrip>
-<p>There also exist some protocol-specific attributes, which are described in protocol sections.
+<p>There also exist some protocol-specific attributes which are described in the corresponding protocol sections.
-<sect>Statements
+<sect>Other statements
<p>The following statements are available:
<tag>accept|reject [ <m/expr/ ]</tag> Accept or reject the route, possibly printing <cf><m>expr</m></cf>.
- <tag>return <m/expr/</tag> Return <cf><m>expr</m></cf> from function, the function ends at this point.
+ <tag>return <m/expr/</tag> Return <cf><m>expr</m></cf> from the current function, the function ends at this point.
<tag>print|printn <m/expr/ [<m/, expr.../]</tag>
Prints given expressions; useful mainly while debugging
filters. The <cf/printn/ variant does not terminate the line.
<tag>quitbird</tag>
- Terminates BIRD. Useful when debugging filter interpreter.
+ Terminates BIRD. Useful when debugging the filter interpreter.
</descrip>
<chapt>Protocols
route) in order to avoid routing loops.
<p>BIRD supports all requirements of the BGP4 standard as defined in
-RFC 1771<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc1771.txt">
-including several enhancements from the
-latest draft<htmlurl url="ftp://ftp.rfc-editor.org/internet-drafts/draft-ietf-idr-bgp4-09.txt">.
-It also supports the community attributes as per
-RFC 1997<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc1997.txt">,
-capability negotiation defined in
-RFC 2842<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc2842.txt">.
+RFC 4271<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc4271.txt">
+It also supports the community attributes
+(RFC 1997<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc1997.txt">),
+capability negotiation
+(RFC 3392<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc3392.txt">),
+MD5 password authentication
+(RFC 2385<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc2385.txt">),
+route reflectors
+(RFC 4456<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc4456.txt">),
+multiprotocol extensions
+(RFC 4760<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc4760.txt">),
+and 4B AS numbers
+(RFC 4893<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc4893.txt">).
+
+
For IPv6, it uses the standard multiprotocol extensions defined in
RFC 2283<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc2283.txt">
including changes described in the
we should route via our direct neighbor with address <m/ip/.
Default: switched off.
- <tag>next hop self</tag> Avoid calculation of the Next Hop attribute
- and always advertise our own source address (see below) as a next hop.
- This needs to be used only
- occasionally to circumvent misconfigurations of other routers.
+ <tag>next hop self</tag> Avoid calculation of the Next Hop
+ attribute and always advertise our own source address (see
+ below) as a next hop. This needs to be used only occasionally
+ to circumvent misconfigurations of other routers.
Default: disabled.
+ <tag>missing lladdr self|drop|ignore</tag>Next Hop attribute
+ in BGP-IPv6 sometimes contains just the global IPv6 address,
+ but sometimes it has to contain both global and link-local
+ IPv6 addresses. This option specifies what to do if BIRD have
+ to send both addresses but does not know link-local address.
+ This situation might happen when routes from other protocols
+ are exported to BGP, or when improper updates are received
+ from BGP peers. <cf/self/ means that BIRD advertises its own
+ local address instead. <cf/drop/ means that BIRD skips that
+ prefixes and logs error. <cf/ignore/ means that BIRD ignores
+ the problem and sends just the global address (and therefore
+ forms improper BGP update). Default: <cf/self/, unless BIRD
+ is configured as a route server (option <cf/rs client/), in
+ that case default is <cf/drop/, because route servers usually
+ does not forward packets ifselves.
+
<tag>source address <m/ip/</tag> Define local address we should use
for next hop calculation. Default: the address of the local end
of the interface our neighbor is connected to.
+ <tag>password <m/string/</tag> Use this password for MD5 authentication
+ of BGP sessions. Default: no authentication. Password has to be set by
+ external utility (e.g. setkey(8)) on BSD systems.
+
+ <tag>passive <m/switch/</tag> Standard BGP behavior is both
+ initiating outgoing connections and accepting incoming
+ connections. In passive mode, outgoing connections are not
+ initiated. Default: off.
+
+ <tag>rr client</tag> Be a route reflector and treat the neighbor as
+ a route reflection client. Default: disabled.
+
+ <tag>rr cluster id <m/IPv4 address/</tag> Route reflectors use cluster id
+ to avoid route reflection loops. When there is one route reflector in a cluster
+ it usually uses its router id as a cluster id, but when there are more route
+ reflectors in a cluster, these need to be configured (using this option) to
+ use a common cluster id. Clients in a cluster need not know their cluster
+ id and this option is not allowed for them. Default: the same as router id.
+
+ <tag>rs client</tag> Be a route server and treat the neighbor
+ as a route server client. A route server is used as a
+ replacement for full mesh EBGP routing in Internet exchange
+ points in a similar way to route reflectors used in IBGP routing.
+ BIRD does not implement obsoleted RFC 1863, but uses ad-hoc implementation,
+ which behaves like plain EBGP but reduces modifications to advertised route
+ attributes to be transparent (for example does not prepend its AS number to
+ AS PATH attribute and keep MED attribute). Default: disabled.
+
+ <tag>enable route refresh <m/switch/</tag> When BGP speaker
+ changes its import filter, it has to re-examine all routes
+ received from its neighbor against the new filter. As these
+ routes might not be available, there is a BGP protocol
+ extension Route Refresh (specified in RFC 2918) that allows
+ BGP speaker to request re-advertisement of all routes from its
+ neighbor. This option specifies whether BIRD advertises this
+ capability and accepts such requests. Even when disabled, BIRD
+ can send route refresh requests. Default: on.
+
+ <tag>interpret communities <m/switch/</tag> RFC 1997 demands
+ that BGP speaker should process well-known communities like
+ no-export (65535, 65281) or no-advertise (65535, 65282). For
+ example, received route carrying a no-adverise community
+ should not be advertised to any of its neighbors. If this
+ option is enabled (which is by default), BIRD has such
+ behavior automatically (it is evaluated when a route is
+ exported to the BGP protocol just before the export filter).
+ Otherwise, this integrated processing of well-known
+ communities is disabled. In that case, similar behavior can be
+ implemented in the export filter. Default: on.
+
+ <tag>enable as4 <m/switch/</tag> BGP protocol was designed to use 2B AS numbers
+ and was extended later to allow 4B AS number. BIRD supports 4B AS extension,
+ but by disabling this option it can be persuaded not to advertise it and
+ to maintain old-style sessions with its neighbors. This might be useful for
+ circumventing bugs in neighbor's implementation of 4B AS extension.
+ Even when disabled (off), BIRD behaves internally as AS4-aware BGP router.
+ Default: on.
+
+ <tag>capabilities <m/switch/</tag> Use capability advertisement
+ to advertise optional capabilities. This is standard behavior
+ for newer BGP implementations, but there might be some older
+ BGP implementations that reject such connection attempts.
+ When disabled (off), features that request it (4B AS support)
+ are also disabled. Default: on, with automatic fallback to
+ off when received capability-related error.
+
+ <tag>advertise ipv4 <m/switch/</tag> Advertise IPv4 multiprotocol capability.
+ This is not a correct behavior according to the strict interpretation
+ of RFC 4760, but it is widespread and required by some BGP
+ implementations (Cisco and Quagga). This option is relevant
+ to IPv4 mode with enabled capability advertisement only. Default: on.
+
+ <tag>route limit <m/number/</tag> The maximal number of routes
+ that may be imported from the protocol. If the route limit is
+ exceeded, the connection is closed with error. Default: no limit.
+
<tag>disable after error <m/switch/</tag> When an error is encountered (either
locally or by the other side), disable the instance automatically
and wait for an administrator to fix the problem manually. Default: off.
<tag>path metric <m/switch/</tag> Enable comparison of path lengths
when deciding which BGP route is the best one. Default: on.
+ <tag>prefer older <m/switch/</tag> Standard route selection algorithm
+ breaks ties by comparing router IDs. This changes the behavior
+ to prefer older routes (when both are external and from different
+ peer). For details, see RFC 5004. Default: off.
+
<tag>default bgp_med <m/number/</tag> Value of the Multiple Exit
Discriminator to be used during route selection when the MED attribute
- is missing. Default: infinite.
-
- <tag>default bgp_local_pref <m/number/</tag> Value of the Local Preference
- to be used during route selection when the Local Preference attribute
is missing. Default: 0.
+
+ <tag>default bgp_local_pref <m/number/</tag> A default value
+ for the Local Preference attribute. It is used when a new
+ Local Preference attribute is attached to a route by the BGP
+ protocol itself (for example, if a route is received through
+ eBGP and therefore does not have such attribute). Default: 100
+ (0 in pre-1.2.0 versions of BIRD).
</descrip>
<sect1>Attributes
selection among multiple BGP routes (see the selection rules above). It's
used as an additional metric which is propagated through the whole local AS.
- <tag>int <cf/bgp_med/ [IO]</tag> The Multiple Exit Discriminator of the route
- is an optional attribute which is often used within the local AS to
- reflect interior distances to various boundary routers. See the route selection
- rules above for exact semantics.
+ <tag>int <cf/bgp_med/ [O]</tag> The Multiple Exit Discriminator of the route
+ is an optional attribute which is used on on external (inter-AS) links to
+ convey to an adjacent AS the optimal entry point into the local AS.
+ The received attribute may be also propagated over internal BGP links
+ (and this is default behavior). The attribute value is zeroed when a route
+ is exported from a routing table to a BGP instance to ensure that the attribute
+ received from a neighboring AS is not propagated to other neighboring ASes.
+ A new value might be set in the export filter of a BGP instance.
+ See RFC 4451<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc4451.txt">
+ for further discussion of BGP MED attribute.
<tag>enum <cf/bgp_origin/</tag> Origin of the route: either <cf/ORIGIN_IGP/
if the route has originated in an interior routing protocol or
policy information like "don't export to USA peers". As each AS can define
its own routing policy, it also has a complete freedom about which community
attributes it defines and what will their semantics be.
+
+ <tag>quad <cf/bgp_originator_id/ [O]</tag> This attribute is created by the
+ route reflector when reflecting the route and contains the router ID of the
+ originator of the route in the local AS.
+
+ <tag>clist <cf/bgp_cluster_list/ [O]</tag> This attribute contains a list
+ of cluster IDs of route reflectors. Each route reflector prepends its
+ cluster ID when reflecting the route.
</descrip>
<sect1>Example
<p><code>
protocol bgp {
- local as 65000; # Use a private AS number
- neighbor 62.168.0.130 as 5588; # Our neighbor...
- multihop 20 via 62.168.0.13; # ... which is connected indirectly
- export filter { # We use non-trivial export rules
- if source = RTS_STATIC then { # Export only static routes
+ local as 65000; # Use a private AS number
+ neighbor 62.168.0.130 as 5588; # Our neighbor ...
+ multihop 20 via 62.168.0.13; # ... which is connected indirectly
+ export filter { # We use non-trivial export rules
+ if source = RTS_STATIC then { # Export only static routes
# Assign our community
bgp_community.add((65000,5678));
# Artificially increase path length
# by advertising local AS number twice
- if bgp_path ~ / 65000 / then
+ if bgp_path ~ [= 65000 =] then
bgp_path.prepend(65000);
accept;
}
reject;
};
import all;
- source address 62.168.0.1; # Use a non-standard source address
+ source address 62.168.0.1; # Use a non-standard source address
}
</code>
this protocol in the configuration since almost all other protocols
require network interfaces to be defined for them to work with.
-<p>The only configurable thing is interface scan time:
+<sect1>Configuration
<p><descrip>
<tag>scan time <m/number/</tag> Time in seconds between two scans
interface status changes asynchronously (such as newer versions of
Linux), we need to scan the list only in order to avoid confusion by lost
notification messages, so the default time is set to a large value.
+
+ <tag>primary [ "<m/mask/" ] <m/prefix/</tag>
+ If a network interface has more than one network address,
+ BIRD has to choose one of them as a primary one, because some
+ routing protocols (for example OSPFv2) suppose there is only
+ one network address per interface. By default, BIRD chooses
+ the lexicographically smallest address as the primary one.
+
+ This option allows to specify which network address should be
+ chosen as a primary one. Network addresses that match
+ <m/prefix/ are preferred to non-matching addresses. If more
+ <cf/primary/ options are used, the first one has the highest
+ preference. If "<m/mask/" is specified, then such
+ <cf/primary/ option is relevant only to matching network
+ interfaces.
+
+ In all cases, an address marked by operating system as
+ secondary cannot be chosen as the primary one.
</descrip>
<p>As the Device protocol doesn't generate any routes, it cannot have
-any attributes. Example configuration looks really simple:
+any attributes. Example configuration looks like this:
<p><code>
protocol device {
scan time 10; # Scan the interfaces often
+ primary "eth0" 192.168.1.1;
+ primary 192.168.0.0/16;
}
</code>
directly connected networks according to the list of interfaces provided
by the kernel via the Device protocol.
-<p>It's highly recommended to include this protocol in your configuration
-unless you want to use BIRD as a route server or a route reflector, that is
-on a machine which doesn't forward packets itself and only participates in
-distribution of routing information.
+<p>The question is whether it is a good idea to have such device
+routes in BIRD routing table. OS kernel usually handles device routes
+for directly connected networks by itself so we don't need (and don't
+want) to export these routes to the kernel protocol. OSPF protocol
+creates device routes for its interfaces itself and BGP protocol is
+usually used for exporting aggregate routes. Although there are some
+use cases that use the direct protocol (like abusing eBGP as an IGP
+routing protocol), in most cases it is not needed to have these device
+routes in BIRD routing table and to use the direct protocol.
<p>The only configurable thing about direct is what interfaces it watches:
<sect>Kernel
<p>The Kernel protocol is not a real routing protocol. Instead of communicating
-the with other routers in the network, it performs synchronization of BIRD's routing
+with other routers in the network, it performs synchronization of BIRD's routing
tables with the OS kernel. Basically, it sends all routing table updates to the kernel
and from time to time it scans the kernel tables to see whether some routes have
disappeared (for example due to unnoticed up/down transition of an interface)
or whether an `alien' route has been added by someone else (depending on the
-<cf/learn/ switch, such routes are either deleted or accepted to our
+<cf/learn/ switch, such routes are either ignored or accepted to our
table).
+<p>Unfortunately, there is one thing that makes the routing table
+synchronization a bit more complicated. In the kernel routing table
+there are also device routes for directly connected networks. These
+routes are usually managed by OS itself (as a part of IP address
+configuration) and we don't want to touch that. They are completely
+ignored during the scan of the kernel tables and also the export of
+device routes from BIRD tables to kernel routing tables is restricted
+to prevent accidental interference. This restriction can be disabled using
+<cf/device routes/ switch.
+
<p>If your OS supports only a single routing table, you can configure only one
instance of the Kernel protocol. If it supports multiple tables (in order to
allow policy routing; such an OS is for example Linux 2.2), you can run as many instances as you want, but each of
routing tables by other routing daemons or by the system administrator.
This is possible only on systems which support identification of route
authorship.
+
+ <tag>device routes <m/switch/</tag> Enable export of device
+ routes to the kernel routing table. By default, such routes
+ are rejected (with the exception of explicitly configured
+ device routes from the static protocol) regardless of the
+ export filter to protect device routes in kernel routing table
+ (managed by OS itself) from accidental overwriting or erasing.
+
<tag>kernel table <m/number/</tag> Select which kernel table should
this particular instance of the Kernel protocol work with. Available
only on systems supporting multiple routing tables.
<sect1>Introduction
<p>Open Shortest Path First (OSPF) is a quite complex interior gateway
-protocol. The current IPv4 version (OSPFv2) is defined in RFC 2328<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc2328.txt">. It's a link
-state (a.k.a. shortest path first) protocol -- Each router maintains a database
-describing the autonomous system's topology. Each participating router
-has an identical copy of the database and all routers run the same algorithm
-calculating a shortest path tree with themselves as a root.
-OSPF chooses the least cost path as the best path.
+protocol. The current IPv4 version (OSPFv2) is defined in RFC
+2328<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc2328.txt"> and
+the current IPv6 version (OSPFv3) is defined in RFC 5340<htmlurl
+url="ftp://ftp.rfc-editor.org/in-notes/rfc5340.txt"> It's a link state
+(a.k.a. shortest path first) protocol -- each router maintains a
+database describing the autonomous system's topology. Each participating
+router has an identical copy of the database and all routers run the
+same algorithm calculating a shortest path tree with themselves as a
+root. OSPF chooses the least cost path as the best path.
<p>In OSPF, the autonomous system can be split to several areas in order
to reduce the amount of resources consumed for exchanging the routing
information and to protect the other areas from incorrect routing data.
Topology of the area is hidden to the rest of the autonomous system.
-Unfortunately multiple OSPF areas are not yet fully supported
-by this version of BIRD and neither is the IPv6 version (OSPFv3).
<p>Another very important feature of OSPF is that
it can keep routing information from other protocols (like Static or BGP)
in its link state database as external routes. Each external route can
-be tagged by the advertising router, making possible to pass additional
+be tagged by the advertising router, making it possible to pass additional
information between routers on the boundary of the autonomous system.
<p>OSPF quickly detects topological changes in the autonomous system (such
-as router interface failures) and calculates new loop-free routes after a
-period of convergence. This period is short and involves only minimal
-routing traffic.
+as router interface failures) and calculates new loop-free routes after a short
+period of convergence. Only a minimal amount of
+routing traffic is involved.
<p>Each router participating in OSPF routing periodically sends Hello messages
to all its interfaces. This allows neighbors to be discovered dynamically.
<sect1>Configuration
-<p>
+<p>In the main part of configuration, there can be multiple definitions of
+OSPF area witch different id included. These definitions includes many other
+switches and multiple definitions of interfaces. Definition of interface
+may contain many switches and constant definitions and list of neighbors
+on nonbroadcast networks.
<code>
protocol ospf <name> {
- rfc1583compat <bool>;
+ rfc1583compat <switch>;
+ tick <num>;
area <id> {
- stub <bool>;
- tick <num>;
- interface <interface pattern>
- {
+ stub cost <num>;
+ networks {
+ <prefix>;
+ <prefix> hidden;
+ }
+ stubnet <prefix>;
+ stubnet <prefix> {
+ hidden <switch>;
+ summary <switch>;
cost <num>;
+ }
+ interface <interface pattern> {
+ cost <num>;
+ stub <switch>;
hello <num>;
+ poll <num>;
retransmit <num>;
priority <num>;
wait <num>;
dead count <num>;
+ dead <num>;
+ rx buffer [normal|large|<num>];
type [broadcast|nonbroadcast|pointopoint];
- authetication [none|simple];
+ strict nonbroadcast <switch>;
+ authentication [none|simple|cryptographic];
password "<text>";
+ password "<text>" {
+ id <num>;
+ generate from "<date>";
+ generate to "<date>";
+ accept from "<date>";
+ accept to "<date>";
+ };
neighbors {
<ip>;
+ <ip> eligible;
};
};
+ virtual link <id> {
+ hello <num>;
+ retransmit <num>;
+ wait <num>;
+ dead count <num>;
+ dead <num>;
+ authentication [none|simple|cryptographic];
+ password "<text>";
+ };
};
}
</code>
<descrip>
- <tag>rfc1583compat <M>bool</M></tag>
+ <tag>rfc1583compat <M>switch</M></tag>
This option controls compatibility of routing table
calculation with RFC 1583<htmlurl
url="ftp://ftp.rfc-editor.org/in-notes/rfc1583.txt">. Default
The most important area is
the backbone (ID 0) to which every other area must be connected.
- <tag>stub <M>bool</M></tag>
- No external routes are flooded into stub areas. Default value is no.
+ <tag>stub cost <M>num</M></tag>
+ No external (except default) routes are flooded into stub areas.
+ Setting this value marks area stub with defined cost of default route.
+ Default value is no. (Area is not stub.)
<tag>tick <M>num</M></tag>
- The routing table calculation is not performed when a single link state
+ The routing table calculation and clean-up of areas' databases
+ is not performed when a single link state
change arrives. To lower the CPU utilization, it's processed later
- at periodical intervals of <m/num/ seconds. The default value is 7.
-
+ at periodical intervals of <m/num/ seconds. The default value is 1.
+
+ <tag>networks { <m/set/ }</tag>
+ Definition of area IP ranges. This is used in summary LSA origination.
+ Hidden networks are not propagated into other areas.
+
+ <tag>stubnet <m/prefix/ { <m/options/ }</tag>
+ Stub networks are networks that are not transit networks
+ between OSPF routers. They are also propagated through an
+ OSPF area as a part of a link state database. By default,
+ BIRD generates a stub network record for each primary network
+ address on each OSPF interface that does not have any OSPF
+ neighbors, and also for each non-primary network address on
+ each OSPF interface. This option allows to alter a set of
+ stub networks propagated by this router.
+
+ Each instance of this option adds a stub network with given
+ network prefix to the set of propagated stub network, unless
+ option <cf/hidden/ is used. It also suppresses default stub
+ networks for given network prefix. When option
+ <cf/summary/ is used, also default stub networks that are
+ subnetworks of given stub network are suppressed. This might
+ be used, for example, to aggregate generated stub networks.
+
<tag>interface <M>pattern</M></tag>
Defines that the specified interfaces belong to the area being defined.
+ See <ref id="dsc-iface" name="interface"> common option for detailed description.
+
+ <tag>virtual link <M>id</M></tag>
+ Virtual link to router with the router id. Virtual link acts as a
+ point-to-point interface belonging to backbone. The actual area is
+ used as transport area. This item cannot be in the backbone.
<tag>cost <M>num</M></tag>
Specifies output cost (metric) of an interface. Default value is 10.
+ <tag>stub <M>switch</M></tag>
+ If set to interface it does not listen to any packet and does not send
+ any hello. Default value is no.
+
<tag>hello <M>num</M></tag>
Specifies interval in seconds between sending of Hello messages. Beware, all
routers on the same network need to have the same hello interval.
Default value is 10.
+ <tag>poll <M>num</M></tag>
+ Specifies interval in seconds between sending of Hello messages for
+ some neighbors on NBMA network. Default value is 20.
+
<tag>retransmit <M>num</M></tag>
Specifies interval in seconds between retransmissions of unacknowledged updates.
Default value is 5.
When the router does not receive any messages from a neighbor in
<m/dead count/*<m/hello/ seconds, it will consider the neighbor down.
+ <tag>dead <M>num</M></tag>
+ When the router does not receive any messages from a neighbor in
+ <m/dead/ seconds, it will consider the neighbor down. If both directives
+ <m/dead count/ and <m/dead/ are used, <m/dead/ has precendence.
+
+ <tag>rx buffer <M>num</M></tag>
+ This sets the size of buffer used for receiving packets. The buffer should
+ be bigger than maximal size of any packets. Value NORMAL (default)
+ means 2*MTU, value LARGE means maximal allowed packet - 65536.
+
<tag>type broadcast</tag>
BIRD detects a type of a connected network automatically, but sometimes it's
convenient to force use of a different type manually.
- On broadcast networks, flooding and Hello messages are sent using multicasts (a single packet for all the neighbors).
+ On broadcast networks, flooding and Hello messages are sent using multicasts
+ (a single packet for all the neighbors).
+
+ <tag>type pointopoint</tag>
+ Point-to-point networks connect just 2 routers together. No election
+ is performed there which reduces the number of messages sent.
<tag>type nonbroadcast</tag>
On nonbroadcast networks, the packets are sent to each neighbor
separately because of lack of multicast capabilities.
- <tag>type pointopoint</tag>
- Point-to-point networks connect just 2 routers together. No election
- is performed there which reduces the number of messages sent.
+ <tag>strict nonbroadcast <M>switch</M></tag>
+ If set, don't send hello to any undefined neighbor. This switch
+ is ignored on any non-NBMA network. Default is No.
<tag>authentication none</tag>
No passwords are sent in OSPF packets. This is the default value.
lacking this password are ignored. This authentication mechanism is
very weak.
+ <tag>authentication cryptographic</tag>
+ 16-byte long MD5 digest is appended to every packet. For the digest
+ generation 16-byte long passwords are used. Those passwords are
+ not sent via network, so this mechanism is quite secure.
+ Packets can still be read by an attacker.
+
<tag>password "<M>text</M>"</tag>
- An 8-byte password used for authentication.
+ An 8-byte or 16-byte password used for authentication.
+ See <ref id="dsc-pass" name="password"> common option for detailed description.
<tag>neighbors { <m/set/ } </tag>
A set of neighbors to which Hello messages on nonbroadcast networks
- are to be sent.
+ are to be sent. Some of them could be marked as eligible.
+
</descrip>
<sect1>Attributes
-<p>OSPF defines three route attributes. Each internal route has a <cf/metric/
+<p>OSPF defines four route attributes. Each internal route has a <cf/metric/.
Metric is ranging from 1 to infinity (65535).
External routes use <cf/metric type 1/ or <cf/metric type 2/.
A <cf/metric of type 1/ is comparable with internal <cf/metric/, a
<cf/metric of type 2/ is always longer
than any <cf/metric of type 1/ or any <cf/internal metric/.
-Each external route can also carry a <cf/tag/ which is a 32-bit
-integer which is used when exporting routes to other protocols;
+<cf/Internal metric/ or <cf/metric of type 1/ is stored in attribute
+<cf/ospf_metric1/, <cf/metric type 2/ is stored in attribute <cf/ospf_metric2/.
+If you specify both metrics only metric1 is used.
+
+Each external route can also carry attribute <cf/ospf_tag/ which is a
+32-bit integer which is used when exporting routes to other protocols;
otherwise, it doesn't affect routing inside the OSPF domain at all.
+The fourth attribute <cf/ospf_router_id/ is a router ID of the router
+advertising that route/network. This attribute is read-only. Default
+is <cf/ospf_metric2 = 10000/ and <cf/ospf_tag = 0/.
<sect1>Example
<code>
protocol ospf MyOSPF {
+ rfc1583compat yes;
+ tick 2;
export filter {
if source = RTS_BGP then {
ospf_metric1 = 100;
accept;
}
- reject;
- };
+ reject;
+ };
area 0.0.0.0 {
- tick 8;
interface "eth*" {
cost 11;
hello 15;
};
interface "ppp*" {
cost 100;
+ authentication cryptographic;
+ password "abc" {
+ id 1;
+ generate to "22-04-2003 11:00:06";
+ accept from "17-01-2001 12:01:05";
+ };
+ password "def" {
+ id 2;
+ generate to "22-07-2005 17:03:21";
+ accept from "22-02-2001 11:34:06";
+ };
+ };
+ interface "arc0" {
+ cost 10;
+ stub yes;
};
+ interface "arc1";
};
area 120 {
stub yes;
+ networks {
+ 172.16.1.0/24;
+ 172.16.2.0/24 hidden;
+ }
interface "-arc0" , "arc*" {
type nonbroadcast;
authentication none;
- wait 50;
- dead count 6;
+ strict nonbroadcast yes;
+ wait 120;
+ poll 40;
+ dead count 8;
neighbors {
- 192.168.120.1;
+ 192.168.120.1 eligible;
192.168.120.2;
192.168.120.10;
};
of routes from the primary table to the secondary one, import filters control the opposite
direction.
+<p>The Pipe protocol may work in the opaque mode or in the transparent
+mode. In the opaque mode, the Pipe protocol retransmits optimal route
+from one table to the other table in a similar way like other
+protocols send and receive routes. Retransmitted route will have the
+source set to the Pipe protocol, which may limit access to protocol
+specific route attributes. The opaque mode is a default mode.
+
+<p>In transparent mode, the Pipe protocol retransmits all routes from
+one table to the other table, retaining their original source and
+attributes. If import and export filters are set to accept, then both
+tables would have the same content. The mode can be set by
+<tt/mode/ option.
+
<p>The primary use of multiple routing tables and the Pipe protocol is for policy routing,
where handling of a single packet doesn't depend only on its destination address, but also
on its source address, source interface, protocol type and other similar parameters.
-In many systems (Linux 2.2 being a good example), the kernel allows to enforce routing policies
+In many systems (Linux being a good example), the kernel allows to enforce routing policies
by defining routing rules which choose one of several routing tables to be used for a packet
according to its parameters. Setting of these rules is outside the scope of BIRD's work
(on Linux, you can use the <tt/ip/ command), but you can create several routing tables in BIRD,
<sect1>Configuration
<p><descrip>
- <tag>peer table <m/table/</tag> Define secondary routing table to connect to. The
+ <tag>peer table <m/table/</tag> Defines secondary routing table to connect to. The
primary one is selected by the <cf/table/ keyword.
+
+ <tag>mode opaque|transparent</tag> Specifies the mode for the pipe to work in. Default is opaque.
</descrip>
<sect1>Attributes
URL="http://www.ietf.org/html.charters/rip-charter.html" name="http://www.ietf.org/html.charters/rip-charter.html">. Both IPv4
(RFC 1723<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc1723.txt">)
and IPv6 (RFC 2080<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc2080.txt">) versions of RIP are supported by BIRD, historical RIPv1 (RFC 1058<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc1058.txt">)is
-not currently supported. RIPv4 md5 authentication (RFC 2082<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc2082.txt">) is supported.
+not currently supported. RIPv4 MD5 authentication (RFC 2082<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc2082.txt">) is supported.
<p>RIP is a very simple protocol, and it has a lot of shortcomings. Slow
convergence, big network load and inability to handle larger networks
-makes it pretty much obsolete in IPv4 world. (It is still usable on
-very small networks.) It is widely used in IPv6 networks,
-because there are no good implementations of OSPFv3.
+makes it pretty much obsolete. (It is still usable on very small networks.)
<sect1>Configuration
<p>In addition to options common for all to other protocols, RIP supports the following ones:
<descrip>
- <tag/authentication none|password|md5/ selects authentication method to be used. <cf/none/ means that
- packets are not authenticated at all, <cf/password/ means that a plaintext password is embedded
- into each packet, and <cf/md5/ means that packets are authenticated using a md5 cryptographic
- hash. If you set authentication to not-none, it is a good idea to add <cf>passwords { }</cf>
+ <tag/authentication none|plaintext|md5/ selects authentication method to be used. <cf/none/ means that
+ packets are not authenticated at all, <cf/plaintext/ means that a plaintext password is embedded
+ into each packet, and <cf/md5/ means that packets are authenticated using a MD5 cryptographic
+ hash. If you set authentication to not-none, it is a good idea to add <cf>password</cf>
section. Default: none.
<tag>honor always|neighbor|never </tag>specifies when should requests for dumping routing table
port 1520;
period 10;
garbage time 60;
- interface "eth0" { metric 3; mode multicast; }
- "eth1" { metric 2; mode broadcast; };
+ interface "eth0" { metric 3; mode multicast; };
+ interface "eth*" { metric 2; mode broadcast; };
honor neighbor;
authentication none;
import filter { print "importing"; accept; };
<p><code>
protocol static {
- table testable; # Connect to a non-default routing table
- route 0.0.0.0/0 via 62.168.0.13; # Default route
- route 62.168.0.0/25 reject; # Sink route
- route 10.2.0.0/24 via "arc0"; # Secondary network
+ table testable; # Connect to a non-default routing table
+ route 0.0.0.0/0 via 62.168.0.13; # Default route
+ route 62.168.0.0/25 reject; # Sink route
+ route 10.2.0.0/24 via "arc0"; # Secondary network
}
</code>
-<chapt>Problems
+<chapt>Conclusions
+
+<sect>Future work
+
+<p>Although BIRD supports all the commonly used routing protocols,
+there are still some features which would surely deserve to be
+implemented in future versions of BIRD:
+
+<itemize>
+<item>OSPF NSSA areas and opaque LSA's
+<item>Route aggregation and flap dampening
+<item>Generation of IPv6 router advertisements
+<item>Multipath routes
+<item>Multicast routing protocols
+<item>Ports to other systems
+</itemize>
+
+<sect>Getting more help
-<p>BIRD is relatively young system, and probably contains some
-bugs. You can report bugs at bird-users mailing list (<HTMLURL URL="mailto:bird-users@bird.network.cz" name="bird-users@bird.network.cz">), but before you do,
-please make sure you have read available documentation, make sure are running latest version (available at <HTMLURL
-URL="ftp://bird.network.cz/pub/bird" name="bird.network.cz:/pub/bird">). (Of course, patch
-which fixes the bug along with bug report is always welcome). If you
-want to use BIRD, join mailing list by sending
-<tt/subscribe bird-users/ to <HTMLURL URL="mailto:majordomo@bird.network.cz" name="majordomo@bird.network.cz">. Main home page of bird is <HTMLURL URL="http://bird.network.cz/" name="http://bird.network.cz/">. When
-trying to understand, what is going on, Internet standards are
-relevant reading; you can get them from <HTMLURL URL="ftp://ftp.rfc-editor.org/" name="ftp.rfc-editor.org"> (or nicely sorted version from <HTMLURL URL="ftp://atrey.karlin.mff.cuni.cz/pub/rfc" name="atrey.karlin.mff.cuni.cz:/pub/rfc">).
+<p>If you use BIRD, you're welcome to join the bird-users mailing list
+(<HTMLURL URL="mailto:bird-users@bird.network.cz" name="bird-users@bird.network.cz">)
+where you can share your experiences with the other users and consult
+your problems with the authors. To subscribe to the list, just send a
+<tt/subscribe bird-users/ command in a body of a mail to
+(<HTMLURL URL="mailto:majordomo@bird.network.cz" name="majordomo@bird.network.cz">).
+The home page of BIRD can be found at <HTMLURL URL="http://bird.network.cz/" name="http://bird.network.cz/">.
+
+<p>BIRD is a relatively young system and it probably contains some
+bugs. You can report any problems to the bird-users list and the authors
+will be glad to solve them, but before you do so,
+please make sure you have read the available documentation and that you are running the latest version (available at <HTMLURL
+URL="ftp://bird.network.cz/pub/bird" name="bird.network.cz:/pub/bird">). (Of course, a patch
+which fixes the bug is always welcome as an attachment.)
+
+<p>If you want to understand what is going inside, Internet standards are
+a good and interesting reading. You can get them from <HTMLURL URL="ftp://ftp.rfc-editor.org/" name="ftp.rfc-editor.org"> (or a nicely sorted version from <HTMLURL URL="ftp://atrey.karlin.mff.cuni.cz/pub/rfc" name="atrey.karlin.mff.cuni.cz:/pub/rfc">).
<p><it/Good luck!/
LocalWords: compat multicasts nonbroadcast pointopoint loopback sym stats
LocalWords: Perl SIGHUP dd mm yy HH MM SS EXT IA UNICAST multihop Discriminator txt
LocalWords: proto wildcard
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projects / thirdparty / bird.git / blobdiff