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Batch of mj's corrections (config + filters)

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This commit is contained in:
Pavel Machek 2000-06-06 20:35:59 +00:00
parent a63a9ce609
commit a7c9f7c065
2 changed files with 133 additions and 167 deletions
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48
bird.conf
View File

@ -9,7 +9,7 @@ router id 62.168.0.1;
define xyzzy = (120+10);
protocol device {
# disabled;
disabled;
# interface "eth*", "ppp*";
}
@ -25,44 +25,13 @@ protocol kernel {
protocol static {
# disabled;
import filter { print "ahoj";
print source;
if source = RTS_STATIC then {
print "It is from static";
}
print from;
from = 1.2.3.4;
print from;
print scope;
scope = SCOPE_HOST;
print scope;
route fec0:2::/64 reject;
route fec0:3::/64 reject;
route fec0:4::/64 reject;
preference = 15;
print preference;
preference = 29;
print preference;
rip_metric = 1;
print rip_metric;
rip_metric = rip_metric + 5;
print rip_metric;
# bgp_community = - empty - ;
# print "nazdar";
# bgp_community = add(bgp_community, (1,2));
# print "cau";
# bgp_community = add(bgp_community, (2,3));
# bgp_community.add((4,5));
# print "community = ", bgp_community;
# bgp_community.delete((2,3));
# print "community = ", bgp_community;
# bgp_community.empty;
# print "community = ", bgp_community;
print "done";
accept;
};
route 0.0.0.0/0 via 195.113.31.113;
route 62.168.0.0/25 reject;
route 1.2.3.4/32 via 195.113.31.124;
# route 0.0.0.0/0 via 195.113.31.113;
# route 62.168.0.0/25 reject;
# route 1.2.3.4/32 via 195.113.31.124;
# route 10.0.0.0/8 reject;
# route 10.1.1.0:255.255.255.0 via 62.168.0.3;
# route 10.1.2.0:255.255.255.0 via 62.168.0.3;
@ -70,3 +39,6 @@ protocol static {
# route 10.2.0.0/24 via "arc0";
export all;
}
protocol rip {
}

244
doc/bird.sgml
View File

@ -96,7 +96,6 @@ Public License.
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.
<sect>Installing BIRD
<p>On a recent UNIX system with GNU development tools (GCC, binutils, m4, make) and Perl, installing BIRD should be as easy as:
@ -270,44 +269,42 @@ protocol rip {
affects one protocol. Only messages in selected debugging categories will be written to the
logs.
<tag>import <m/filter/</tag> filter can be either either <cf> { <m>filter commands</m>
}</cf> or <cf>filter <m/name/</cf> or <cf/all/ or <cf/none/. Import filter works in direction from protocol to main
routing table. All is shorthand for <cf/{ accept; }/ and none is shorthand for <cf/{ reject; }/.
<tag>import { <m/filter commands/ } | <m/name/ | all | none</tag> Specify a filter to be used for filtering routes comming from protocol tothe routing table. Default: <cf/all/. <cf/all/ is shorthand for <cf/{ accept; }/ and <cf/none/ is shorthand for <cf/{ reject; }/.
<tag>export <m/filter/</tag> This is similar to <cf>export</cf> keyword, except that it
works in direction from main routing table to protocol.
<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>table <m/name/</tag> Connect this protocol to non-default table.
<tag>table <m/name/</tag> Connect this protocol to a non-default routing table.
</descrip>
<p>There are per-protocol options that give sense only with certain protocols.
<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. Passive time is
time from which password is not announced, but is recognized on reception. id is password id, as needed by
<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.
<tag>interface "<m/mask/"|<m/prefix/ [ { <m/option/ ; [ ... ] } ]</tag> specifies, which
interfaces this protocol is active at, and allows you to set options on
interface-by-interface basis. Mask is specified in shell-like patters, thus <cf>interface
"*" { mode broadcast; };</cf> will start given protocol on all interfaces, with <cf>mode
<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 "-eth0", "*";/ means all but
excluded. Masks are parsed left-to-right, thus <cf/interface "-eth*", "*";/ means all but
the ethernets.
</descrip>
<sect>Client
<p>You can use command-line client <file>birdc</file> to talk with
running BIRD. Communications is done using <file/bird.ctl/ unix domain
socket (unless changed with <tt/-s/ option given to both server and
client). Client can do simple actions such as enabling/disabling
<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 client, telling it to dump numeric return
<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).
@ -317,16 +314,15 @@ BIRD and BIRDC is stable (see programmer's documentation).
<sect>Introduction
<p>BIRD contains rather simple programming language. (No, it can not yet read mail :-). There are
two objects in this language: filters and functions. Filters are called by BIRD core when route is
being passed between protocol and main routing table, and filters may call functions. Functions may
call other functions, but recursion is not allowed. Filter language contains control structures such
<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 protocola and routing tables. Filter language contains control structures such
as if's and switches, but it allows no loops. Filters are
interpreted. Filter using many features can be found in <file>filter/test.conf</file>.
interpreted. An example of a filter using many features can be found in <file>filter/test.conf</file>.
<p>Filter basically gets the route, looks at its attributes and
modifies some of them if it wishes. At the end, it decides, whether to
pass change route through (using <cf/accept/), or whether to <cf/reject/ given route. Simple filter looks
<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
like this:
<code>
@ -346,15 +342,15 @@ int var;
}
</code>
<p>As you can see, filter has a header, list of local variables, and body. Header consists of
<cf/filter/ keyword, followed by (unique) name of filter. List of local variables consists of
<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 Statement is terminated by <cf/;/. You can group
several statements into one by <cf>{ <M>statements</M> }</cf> construction, that is useful if
<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 can have local variables. They
over. Functions can have zero or more parameters and they can have local variables. Recursion is not allowed. They
look like this:
<code>
@ -370,27 +366,24 @@ function with_parameters (int parameter)
}
</code>
<p>Unlike C, variables are declared after function line but before first {. You can not declare
<p>Unlike in C, variables are declared after function line but before the first {. 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 <cf>return <m/[expr]/</cf>
syntax. Returning value exits from current function (this is similar to C).
with_parameters(5);</cf>. Function may return value 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 similar way to functions, except they can not have explicit
parameters. They get route table entry as implicit parameter. Route table entry is passed implicitly
to any functions being called. Filter must terminate with either
<cf/accept/ or <cf/reject/ statement. If there's runtime error in filter, route
<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
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
is rejected.
<p>Nice trick to debug filters is using <cf>show route filter
<m/name/</cf> from command line client. Example session might look
<p>A nice trick to debug filters is to use <cf>show route filter
<m/name/</cf> from the command line client. An example session might look
like:
<code>
pavel@bug:~/bird$ ./birdc -s bird.ctl
BIRD 0.0.0 ready.
bird> help
No such command.
bird>
bird> show route
10.0.0.0/8 dev eth0 [direct1 23:21] (240)
195.113.30.2/32 dev tunl1 [direct1 23:21] (240)
@ -404,32 +397,32 @@ bird>
<sect>Data types
<p>Each variable and each value has certain type. Unlike C, booleans, integers and enums are
<p>Each variable and each value has certain type. Booleans, integers and enums are
incompatible with each other (that is to prevent you from shooting in the foot).
<descrip>
<tag/bool/ this is boolean type, it can have only two values, <cf/true/ and
<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
statements.
<tag/int/ this is common integer, you can expect it to store signed values from -2000000000
to +2000000000. Overflows are not checked.
<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 pair of two short integers. Each component can have values from 0 to
65535. Constant of this type is written as <cf/(1234,5678)/.
<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)/.
<tag/string/ this is string of characters. There are no ways to modify strings in
filters. You can pass them between functions, assign to variable of type string, print
such variables, but you can not concatenate two strings (for example). String constants
<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
such variables, but you can't concatenate two strings. String literals
are written as <cf/"This is a string constant"/.
<tag/ip/ this type can hold single ip address. Depending on compile-time configuration of BIRD you are using, it
can be IPv4 or IPv6 address. IPv4 addresses are written (as you would expect) as
<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. IPv4 addresses are written (as you would expect) as
<cf/1.2.3.4/. 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
address. So <cf/1.2.3.4.mask(8) = 1.0.0.0/ is true.
address. So <cf/1.2.3.4.mask(8) = 1.0.0.0/ is true. <!-- FIXME: IPv6? -->
<tag/prefix/ this type can hold ip address and prefix length. Prefixes are written as
<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:
@ -437,67 +430,71 @@ incompatible with each other (that is to prevent you from shooting in the foot).
len from the pair. So <cf>1.2.0.0/16.pxlen = 16</cf> is true.
<tag/int|ip|prefix|pair|enum set/
filters know four types of sets. Sets are similar to strings: you can pass them around
but you can not modify them. Constant of type <cf>set int</cf> looks like <cf>
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>
[ 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>. 3.0.0.0/8{5,6} matches
prefixes 3.X.X.X, whose prefix length is 5 to 6. 3.0.0.0/8+ is shorthand for 3.0.0.0/{0,8},
3.0.0.0/8- is shorthand for 3.0.0.0/{0,7}. For example,
<tt>1.2.0.0/16 ~ [ 1.0.0.0/8{ 15 , 17 } ]</tt> is true, but
<tt>1.0.0.0/8 ~ [ 1.0.0.0/8- ]</tt> is false.
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>3.0.0.0/8+</cf> is shorthand for <cf>3.0.0.0/{0,8}</cf>,
<cf>3.0.0.0/8-</cf> is shorthand for <cf>3.0.0.0/{0,7}</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. <!-- fixme: use variables instead of examples -->
<tag/enum/
enumeration types are halfway-internal in the BIRD. You can't define your own
variable of enumeration type, but some route attributes are of enumeration
type. Enumeration types are incompatible with each other, again, for your
protection.
Enumeration types are fixed in BIRD - you can't define your own
variables of enumeration type, but some route attributes are of enumeration
type. Enumeration types are incompatible with each other.
<tag/bgppath/
bgp path is list of autonomous systems. You can't write constant of this type.
BGP path is a list of autonomous system numbers. You can't write literals of this type.
<tag/bgpmask/
bgp mask is mask used for matching bgp paths
(using <cf>path ~ / 2 3 5 ? / syntax </cf>). Matching is
done using shell-like pattern: <cf/?/ means
BGP mask is a mask used for matching BGP paths
(using <cf>path &tilde; /2 3 5 ?/</cf> syntax). Matching is
done using shell-like patterns: <cf/?/ means
"any number of any autonomous systems". Pattern for single
unknown autonomous system is not supported. (We
did not want to use * because then it becomes too easy to
write <cf>/*</cf> which is start of comment.) For example,
<tt>/4 3 2 1/ ~ /? 4 3 ?/</tt> is true, but
<tt>/ 4 3 2 1 / ~ / ? 4 5 ? /</tt> is false.
<tt>/4 3 2 1/ ~ /? 4 5 ?/</tt> is false. <!-- fixme: formulate better -->
<tag/clist/
community list. This is similar to set of pairs,
Community list is similar to set of pairs,
except that unlike other sets, it can be modified.
You can't write constant of this type.
There exist no literals of this type.
</descrip>
<sect>Operations
<sect>Operators
<p>Filter language supports common integer operations <cf>(+,-,*,/)</cf>, parentheses <cf/(a*(b+c))/, comparison
<!-- FIXME: Make it table -->
<p>The filter language supports common integer operators <cf>(+,-,*,/)</cf>, parentheses <cf/(a*(b+c))/, comparison
<cf/(a=b, a!=b, a&lt;b, a&gt;=b)/. Special operators include <cf/&tilde;/ for "in" operation. In operation can be
used on element and set of that elements, or on ip and prefix, or on
prefix and prefix or on bgppath and bgpmask or on pair and clist. Its result
is true if element is in given set or if ip address is inside given prefix. Logical operations include unary not (<cf/!/), and (<cf/&&/) and or (<cf/||/>).
is true if element is in given set or if ip address is inside given prefix. Logical operations include unary not (<cf/!/), and (<cf/&&/) and or (<cf/||/).
<sect>Control structures
<p>Filters support two control structures: if/then/else and case. Syntax of if/then/else is <cf>if
<M>expression</M> then <M>command</M>; else <M>command</M>;</cf> and you can use <cf>{
<p>Filters support two control structures: conditions and case switches.
<!-- fixme: say explicitly what if and case does -->
<p>Syntax of condition is <cf>if
<M>boolean expression</M> then <M>command</M>; else <M>command</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.
<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 &tilde; operator, and anything that could
be member of set is allowed before <cf/:/. Multiple commands are allowed without <cf/{}/ grouping
<cf>case</cf> can be of any type that can be on the left side of the &tilde; 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 argument
matches neither of <cf/:/ clauses, <cf/else:/ clause is used. (Case is actually implemented as set matching,
internally.)
matches neither of <cf/:/ clauses, <cf/else:/ clause is used.
<p>Here is example that uses if and case structures:
<p>Here is example that uses <cf/if/ and <cf/case/ structures:
<code>
case arg1 {
@ -514,58 +511,58 @@ if 1234 = i then printn "."; else {
<sect>Route attributes
<p>Filter is implicitly passed route, and it can access its
attributes, just like it accesses variables. Access to undefined
attribute results in runtime error; you can check if attribute is
defined using <cf>defined( <m>attribute</m> )</cf> syntax.
<p>An filter is implicitly passed route, and it can access its
attributes just like it accesses variables. Attempt 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.
<!-- fixme: say which are read-only -->
<descrip>
<tag><m/prefix/ net</tag>
network this route is talking about. (See section about routing tables)
<tag><m/int/ preference</tag>
preference of this route. (See section about routing tables)
<tag><m/ip/ from</tag>
who told me about this route.
<tag><m/ip/ gw</tag>
what is next hop packets routed using this route should be forwarded to.
<tag><m/enum/ source</tag>
what protocol told me about this route. This can have values such as <cf/RTS_RIP/ or <cf/RTS_OSPF_EXT/.
Network the route is talking about. (See the section about routing tables.)
<tag><m/enum/ scope</tag>
FIXME!
Address scope of the network (<cf/SCOPE_HOST/ for addresses local to this host, <cf/SCOPE_LINK for those specific for a physical link, ... <!-- FIXME -->)
<tag><m/int/ preference</tag>
Preference of the route. (See section about routing tables.)
<tag><m/ip/ from</tag>
The router which the route has originated from.
<tag><m/ip/ gw</tag>
Next hop packets routed using this route should be forwarded to.
<tag><m/enum/ source</tag>
what protocol has told me about this route. Possible values: <cf/RTS_RIP/ or <cf/RTS_OSPF_EXT/ <!-- fixme -->.
<tag><m/enum/ cast</tag>
FIXME!
Route type (<cf/RTC_UNICAST/ for normal routes, ... <!-- FIXME -->)
<tag><m/enum/ dest</tag>
FIXME!
Type of destination the packets should be sent to (<cf/RTD_ROUTER/ for forwarding to a neighboring router, ...)
</descrip>
<p>Then there are protocol-specific attributes, which are described in protocol sections.
<p>There also exist some protocol-specific attributes, which are described in protocol sections.
<sect>Statements
<p>Following statements are supported:
<p>The following statements are available:
<descrip>
<tag><m/variable/ = <m/expr/</tag> set variable to give value.
<tag><m/variable/ = <m/expr/</tag> Set variable to a given value.
<tag>accept [ <m/expr/ ]</tag> accept this route, possibly printing expr
<tag>accept|reject [ <m/expr/ ]</tag> Accept or reject the route, possibly printing <cf><m>expr</m></cf>.
<tag>reject</tag> reject this route
<tag>return <m/expr/</tag> return given value from function, function ends at this point.
<tag>return <m/expr/</tag> Return <cf><m>expr</m></cf> from function, the function ends at this point.
<tag>print|printn <m/expr/ [<m/, expr.../]</tag>
prints given expressions, useful mainly while debugging
filters. Printn variant does not go to new line.
Prints given expressions; useful mainly while debugging
filters. The <cf/printn/ variant does not terminate the line.
<tag>quitbird</tag>
terminates bird. Useful while debugging filter interpreter.
Terminates BIRD. Useful when debugging filter interpreter.
</descrip>
<chapt>Protocols
@ -991,7 +988,7 @@ it and broadcasts it back. Broadcasts are done in regular intervals. Therefore,
unreachable, routers keep telling each other that distance is old distance plus 1 (actually, plus
interface metric, which is usually one). After some time, distance reaches infinity (that's 15 in
rip) and all routers know that network is unreachable. Rip tries to minimize situations where
counting to infinity is necessary, because it is slow. Due to infinity being 16, you can not use
counting to infinity is necessary, because it is slow. Due to infinity being 16, you can't use
rip on networks where maximal distance is bigger than 15 hosts. You can read more about rip at <HTMLURL
URL="http://www.ietf.org/html.charters/rip-charter.html">. Both IPv4
and IPv6 versions of rip are supported by BIRD, historical RIPv1 is
@ -1134,17 +1131,14 @@ protocol static {
<chapt>Problems
<p>BIRD is relatively young system, and probably contains some
bugs. You can report bugs at <HTMLURL URL="fixme">, but before you do,
bugs. You can report bugs at bird-users mailing list (<HTMLURL URL="mailto:bird-users@bird.network.cz" TEXT="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="fixme">), and that bug was not already reported by someone else
(mailing list archives are at <HTMLURL URL="fixme">). (Of course, patch
URL="ftp://bird.network.cz/pub/bird" TEXT="bird.network.cz:/pub/bird>). (Of course, patch
which fixes the bug along with bug report is always welcome). If you
want to join the development, join developer's mailing list by sending
<tt/????/ to <HTMLURL URL="fixme">. You can also get current sources from
anoncvs at <HTMLURL URL="fixme">. You can find this documentation online
at <HTMLURL URL="fixme">, main home page of bird is <HTMLURL URL="fixme">. When
want to use BIRD, join mailing list by sending
<tt/subscribe bird-users/ to <HTMLURL URL="mailto:majordomo@bird.network.cz" TEXT="majordomo@bird.network.cz">. Main home page of bird is <HTMLURL URL="http://bird.network.cz/" TEXT="http://bird.network.cz/">. When
trying to understand, what is going on, Internet standards are
relevant reading; you can get them from <HTMLURL URL="fixme">.
relevant reading; you can get them from <HTMLURL URL="ftp://ftp.rfc-editor.org/" TEXT="ftp.rfc-editor.org"> (or nicely sorted version from <HTMLURL="ftp://atrey.karlin.mff.cuni.cz/pub/rfc" TEXT="atrey.karlin.mff.cuni.cz:/pub/rfc">.
<p><it/Good luck!/