<LI><A HREF="#Interception">Interception</A></LI>
<LI><A HREF="#Authentication">Authentication</A></LI>
<LI><A HREF="#Plugins">Plugins</A></LI>
- <LI><A HREF="#Walled Garden">Walled Garden</A></LI>
+ <LI><A HREF="#WalledGarden">Walled Garden</A></LI>
+ <LI><A HREF="#Filtering">Filtering</A></LI>
<LI><A HREF="#Clustering">Clustering</A></LI>
<LI><A HREF="#Routing">Routing</A></LI>
+ <LI><A HREF="#AvoidingFragmentation">Avoiding Fragmentation</A></LI>
<LI><A HREF="#Performance">Performance</A></LI>
</OL>
protocol (e.g. Ethernet, PPP) to be tunneled over an IP connection. l2tpns
implements PPP over L2TP only.<P>
-There are a couple of other L2TP imlementations, of which <A
+There are a couple of other L2TP im
plementations, of which <A
HREF="http://sourceforge.net/projects/l2tpd">l2tpd</A> is probably the
most popular. l2tpd also will handle being either end of a tunnel, and
is a lot more configurable than l2tpns. However, due to the way it works,
one will not be sent.
</LI>
-<LI><B>save_state</B> (boolean)<BR>
-When l2tpns receives a STGTERM it will write out its current
-ip_address_pool, session and tunnel tables to disk prior to exiting to
-be re-loaded at startup. The validity of this data is obviously quite
-short and the intent is to allow an sessions to be retained over a
-software upgrade.
-</LI>
-
<LI><B>primary_radius</B> (ip address)
<LI><B>secondary_radius</B> (ip address)<BR>
-Sets the radius servers used for both authentication and accounting.
-If the primary server does not respond, then the secondary radius
-server will be tried.
+Sets the RADIUS servers used for both authentication and accounting.
+If the primary server does not respond, then the secondary RADIUS
+server will be tried.<br>
+<strong>Note:</strong> in addition to the source IP address and
+identifier, the RADIUS server <strong>must</strong> include the source
+port when detecting duplicates to supress (in order to cope with a
+large number of sessions comming on-line simultaneously l2tpns uses a
+set of udp sockets, each with a seperate identifier).
</LI>
<LI><B>primary_radius_port</B> (short)
<LI><B>secondary_radius_port</B> (short)<BR>
-Sets the authentication ports for the primary and secondary radius
+Sets the authentication ports for the primary and secondary RADIUS
servers. The accounting port is one more than the authentication
-port. If no radius ports are given, the authentication port defaults
+port. If no RADIUS ports are given, the authentication port defaults
to 1645, and the accounting port to 1646.
</LI>
<LI><B>radius_accounting</B> (boolean)<BR>
-If set to true, then radius accounting packets will be sent. This
+If set to true, then RADIUS accounting packets will be sent. This
means that a Start record will be sent when the session is
successfully authenticated, and a Stop record will be sent when the
session is closed.
</LI>
<LI><B>radius_secret</B> (string)<BR>
-This secret will be used in all radius queries. If this is not set then
-radius queries will fail.
+This secret will be used in all RADIUS queries. If this is not set then
+RADIUS queries will fail.
+</LI>
+
+<LI><B>radius_authtypes</B> (string)</BR>
+A comma separated list of supported RADIUS authentication methods
+(<B>pap</B> or <B>chap</B>), in order of preference (default <B>pap</B>).
+</LI>
+
+<LI><B>radius_dae_port</B> (short)<BR>
+Port for DAE RADIUS (Packet of Death/Disconnect, Change of Authorization)
+requests (default: <B>3799</B>).
+</LI>
+
+<LI><B>allow_duplicate_users</B> (boolean)</BR>
+Allow multiple logins with the same username. If false (the default),
+any prior session with the same username will be dropped when a new
+session is established.
</LI>
<LI><B>bind_address</B> (ip address)<BR>
the <EM>uptime</EM> command on the CLI.
</LI>
-<LI><B>cleanup_interval</B> (int)<BR>
-Interval between regular cleanups (in seconds).
-</LI>
-
<LI><B>multi_read_count</B> (int)<BR>
Number of packets to read off each of the UDP and TUN fds when
returned as readable by select (default: 10). Avoids incurring the
Maximum number of host unreachable ICMP packets to send per second.
</LI>
+<LI><B>packet_limit</B> (int><BR>
+Maximum number of packets of downstream traffic to be handled each
+tenth of a second per session. If zero, no limit is applied (default:
+0). Intended as a DoS prevention mechanism and not a general
+throttling control (packets are dropped, not queued).
+</LI>
+
<LI><B>cluster_address</B> (ip address)<BR>
Multicast cluster address (default: 239.192.13.13). See the section
on <A HREF="#Clustering">Clustering</A> for more information.
elected when this interval has been passed without seeing a heartbeat
from the master.
</LI>
+
+<LI><B>cluster_master_min_adv</B> (int)<BR>
+Determines the minumum number of up to date slaves required before the
+master will drop routes (default: 1).
+</LI>
</UL>
<P>BGP routing configuration is entered by the command:
IP address, <I>as</I> is the remote AS number and <I>keepalive</I>,
<I>hold</I> are the timer values in seconds.
+<P>Named access-lists are configured using one of the commands:
+<DL>
+ <DD><B>ip access-list standard</B> <I>name</I>
+ <DD><B>ip access-list extended</B> <I>name</I>
+</DL>
+
+<P>Subsequent lines prefixed with <B>permit</B> or <B>deny</B>
+define the body of the access-list. Standard access-list syntax:
+<DL>
+ <DD>{<B>permit</B>|<B>deny</B>}
+ {<I>host</I>|<I>source source-wildcard</I>|<B>any</B>}
+ [{<I>host</I>|<I>destination destination-wildcard</I>|<B>any</B>}]
+</DL>
+
+Extended access-lists:
+
+<DIV STYLE="margin-left: 4em; text-indent: -2em">
+ <P>{<B>permit</B>|<B>deny</B>} <B>ip</B>
+ {<I>host</I>|<I>source source-wildcard</I>|<B>any</B>}
+ {<I>host</I>|<I>destination destination-wildcard</I>|<B>any</B>} [<B>fragments</B>]
+ <P>{<B>permit</B>|<B>deny</B>} <B>udp</B>
+ {<I>host</I>|<I>source source-wildcard</I>|<B>any</B>}
+ [{<B>eq</B>|<B>neq</B>|<B>gt</B>|<B>lt</B>} <I>port</I>|<B>range</B> <I>from</I> <I>to</I>]
+ {<I>host</I>|<I>destination destination-wildcard</I>|<B>any</B>}
+ [{<B>eq</B>|<B>neq</B>|<B>gt</B>|<B>lt</B>} <I>port</I>|<B>range</B> <I>from</I> <I>to</I>]
+ [<B>fragments</B>]
+ <P>{<B>permit</B>|<B>deny</B>} <B>tcp</B>
+ {<I>host</I>|<I>source source-wildcard</I>|<B>any</B>}
+ [{<B>eq</B>|<B>neq</B>|<B>gt</B>|<B>lt</B>} <I>port</I>|<B>range</B> <I>from</I> <I>to</I>]
+ {<I>host</I>|<I>destination destination-wildcard</I>|<B>any</B>}
+ [{<B>eq</B>|<B>neq</B>|<B>gt</B>|<B>lt</B>} <I>port</I>|<B>range</B> <I>from</I> <I>to</I>]
+ [{<B>established</B>|{<B>match-any</B>|<B>match-all</B>}
+ {<B>+</B>|<B>-</B>}{<B>fin</B>|<B>syn</B>|<B>rst</B>|<B>psh</B>|<B>ack</B>|<B>urg</B>}
+ ...|<B>fragments</B>]
+</DIV>
+
<H3 ID="users">users</H3>
Usernames and passwords for the command-line interface are stored in
</LI>
<LI><B>show radius</B><BR>
-Show a summary of the in-use radius sessions. This list should not be very
-long, as radius sessions should be cleaned up as soon as they are used. The
+Show a summary of the in-use RADIUS sessions. This list should not be very
+long, as RADIUS sessions should be cleaned up as soon as they are used. The
columns listed are:
<TABLE>
- <TR><TD><B>Radius</B></TD><TD>The ID of the radius request. This is
- sent in the packet to the radius server for identification.</TD></TR>
+ <TR><TD><B>Radius</B></TD><TD>The ID of the RADIUS request. This is
+ sent in the packet to the RADIUS server for identification.</TD></TR>
<TR><TD><B>State</B></TD><TD>The state of the request - WAIT, CHAP,
AUTH, IPCP, START, STOP, NULL.</TD></TR>
- <TR><TD><B>Session</B></TD><TD>The session ID that this radius
+ <TR><TD><B>Session</B></TD><TD>The session ID that this RADIUS
request is associated with</TD></TR>
<TR><TD><B>Retry</B></TD><TD>If a response does not appear to the
request, it will retry at this time. This is a unix timestamp.</TD></TR>
- <TR><TD><B>Try</B></TD><TD>Retry count. The radius request is
+ <TR><TD><B>Try</B></TD><TD>Retry count. The RADIUS request is
discarded after 3 retries.</TD></TR>
</TABLE>
<P>
host/port. Specify <EM>no snoop username</EM> to disable interception
for the session.<P>
-If you want interception to be permanent, you will have to modify the radius
+If you want interception to be permanent, you will have to modify the RADIUS
response for the user. See <A HREF="#Interception">Interception</A>.
<P>
</LI>
for the current session.<P>
If you want throttling to be permanent, you will have to modify the
-radius response for the user. See <A HREF="#THrottling">Throttling</A>.
+RADIUS response for the user. See <A HREF="#Throttling">Throttling</A>.
<P>
</LI>
</PRE>
The signals understood are:
-<UL>
-<LI>SIGHUP - Reload the config from disk and re-open log file<P></LI>
-<LI>SIGTERM / SIGINT - Shut down for a restart. This will dump the current
-state to disk (if <EM>save_state</EM> is set to true). Upon restart, the
-process will read this saved state to resume active sessions.<P>
-<LI>SIGQUIT - Shut down cleanly. This will send a disconnect message for
-every active session and tunnel before shutting down. This is a good idea
-when upgrading the code, as no sessions will be left with the remote end
-thinking they are open.</LI>
-</UL>
+<DL>
+<DT>SIGHUP</DT><DD>Reload the config from disk and re-open log file.</DD>
+<DT>SIGTERM, SIGINT</DT><DD>Stop process. Tunnels and sessions are not
+terminated. This signal should be used to stop l2tpns on a
+<A HREF="#Clustering">cluster node</A> where there are other machines to
+continue handling traffic.</DD>
+<DT>SIGQUIT</DT><DD>Shut down tunnels and sessions, exit process when
+complete.</DD>
+</DL>
<H2 ID="Throttling">Throttling</H2>
before this will be activated.<P>
If you wish a session to be throttled permanently, you should set the
-Vendor-Specific radius value <B>Cisco-Avpair="throttle=yes"</B>, which
+Vendor-Specific RADIUS value <B>Cisco-Avpair="throttle=yes"</B>, which
will be handled by the <EM>autothrottle</EM> module.<P>
Otherwise, you can enable and disable throttling an active session using
immediately.<P>
If you wish the user to be intercepted whenever they reconnect, you will
-need to modify the radius response to include the Vendor-Specific value
+need to modify the RADIUS response to include the Vendor-Specific value
<B>Cisco-Avpair="intercept=yes"</B>. For this feature to be enabled,
you need to have the <EM>autosnoop</EM> module loaded.<P>
completed. The remote end must send a PPP CHAP or PPP PAP authentication
request to l2tpns.<P>
-This request is sent to the radius server, which will hopefully respond with
+This request is sent to the RADIUS server, which will hopefully respond with
Auth-Accept or Auth-Reject.<P>
If Auth-Accept is received, the session is set up and an IP address is
-assigned. The radius server can include a Framed-IP-Address field in the
+assigned. The RADIUS server can include a Framed-IP-Address field in the
reply, and that address will be assigned to the client. It can also include
specific DNS servers, and a Framed-Route if that is required.<P>
PPP AUTHACK, but their session is flagged as being a garden'd user, and they
should not receive any service.<P>
-The radius reply can also contain a Vendor-Specific attribute called
+The RADIUS reply can also contain a Vendor-Specific attribute called
Cisco-Avpair. This field is a freeform text field that most Cisco
devices understand to contain configuration instructions for the session. In
the case of l2tpns it is expected to be of the form
<TABLE CELLSPACING=1 CELLPADDING=3>
<TR BGCOLOR=LIGHTGREEN><TH><B>Event</B></TH><TH><B>Description</B></TH><TH><B>Parameters</B></TH></TR>
<TR VALIGN=TOP BGCOLOR=WHITE><TD><B>pre_auth</B></TD>
- <TD>This is called after a radius response has been
+ <TD>This is called after a RADIUS response has been
received, but before it has been processed by the
code. This will allow you to modify the response in
some way.
</TD>
<TD>
- <UL>
- <LI>t - Tunnel ID</LI>
- <LI>s - Session ID</LI>
- <LI>username</LI>
- <LI>password</LI>
- <LI>protocol (0xC023 for PAP, 0xC223 for CHAP)</LI>
- <LI>continue_auth - Set to 0 to stop processing authentication modules</LI>
- </UL>
+ <DL>
+ <DT>t<DD>Tunnel
+ <DT>s<DD>Session
+ <DT>username
+ <DT>password
+ <DT>protocol<DD>0xC023 for PAP, 0xC223 for CHAP
+ <DT>continue_auth<DD>Set to 0 to stop processing authentication modules
+ </DL>
</TD>
</TR>
<TR VALIGN=TOP BGCOLOR=WHITE><TD><B>post_auth</B></TD>
- <TD>This is called after a radius response has been
+ <TD>This is called after a RADIUS response has been
received, and the basic checks have been performed. This
is what the garden module uses to force authentication
to be accepted.
</TD>
<TD>
- <UL>
- <LI>t - Tunnel ID</LI>
- <LI>s - Session ID</LI>
- <LI>username</LI>
- <LI>auth_allowed - This is already set to true or
+ <DL>
+ <DT>t<DD>Tunnel
+ <DT>s<DD>Session
+ <DT>username
+ <DT>auth_allowed<DD>This is already set to true or
false depending on whether authentication has been
allowed so far. You can set this to 1 or 0 to force
- allow or disallow authentication</LI>
- <LI>protocol (0xC023 for PAP, 0xC223 for CHAP)</LI>
- </UL>
+ allow or disallow authentication
+ <DT>protocol<DD>0xC023 for PAP, 0xC223 for CHAP
+ </DL>
</TD>
</TR>
<TR VALIGN=TOP BGCOLOR=WHITE><TD><B>packet_rx</B></TD>
seriously slow down the system.</FONT>
</TD>
<TD>
- <UL>
- <LI>t - Tunnel ID</LI>
- <LI>s - Session ID</LI>
- <LI>buf - The raw packet data</LI>
- <LI>len - The length of buf</LI>
- </UL>
+ <DL>
+ <DT>t<DD>Tunnel
+ <DT>s<DD>Session
+ <DT>buf<DD>The raw packet data
+ <DT>len<DD>The length of buf
+ </DL>
</TD>
</TR>
<TR VALIGN=TOP BGCOLOR=WHITE><TD><B>packet_tx</B></TD>
seriously slow down the system.</FONT>
</TD>
<TD>
- <UL>
- <LI>t - Tunnel ID</LI>
- <LI>s - Session ID</LI>
- <LI>buf - The raw packet data</LI>
- <LI>len - The length of buf</LI>
- </UL>
+ <DL>
+ <DT>t<DD>Tunnel
+ <DT>s<DD>Session
+ <DT>buf<DD>The raw packet data
+ <DT>len<DD>The length of buf
+ </DL>
</TD>
</TR>
<TR VALIGN=TOP BGCOLOR=WHITE><TD><B>timer</B></TD>
you do is reentrant.
</TD>
<TD>
- <UL>
- <LI>time_now - The current unix timestamp</LI>
- </UL>
+ <DL>
+ <DT>time_now<DD>The current unix timestamp
+ </DL>
</TD>
</TR>
<TR VALIGN=TOP BGCOLOR=WHITE><TD><B>new_session</B></TD>
session is now ready to handle traffic.
</TD>
<TD>
- <UL>
- <LI>t - Tunnel ID</LI>
- <LI>s - Session ID</LI>
- </UL>
+ <DL>
+ <DT>t<DD>Tunnel
+ <DT>s<DD>Session
+ </DL>
</TD>
</TR>
<TR VALIGN=TOP BGCOLOR=WHITE><TD><B>kill_session</B></TD>
This may be called multiple times for the same session.
</TD>
<TD>
- <UL>
- <LI>t - Tunnel ID</LI>
- <LI>s - Session ID</LI>
- </UL>
+ <DL>
+ <DT>t<DD>Tunnel
+ <DT>s<DD>Session
+ </DL>
</TD>
</TR>
<TR VALIGN=TOP BGCOLOR=WHITE><TD><B>radius_response</B></TD>
- <TD>This is called whenever a radius response includes a
+ <TD>This is called whenever a RADIUS response includes a
Cisco-Avpair value. The value is split up into
<EM>key=value</EM> pairs, and each is processed through all
modules.
</TD>
<TD>
- <UL>
- <LI>t - Tunnel ID</LI>
- <LI>s - Session ID</LI>
- <LI>key</LI>
- <LI>value</LI>
- </UL>
+ <DL>
+ <DT>t<DD>Tunnel
+ <DT>s<DD>Session
+ <DT>key
+ <DT>value
+ </DL>
+ </TD>
+ </TR>
+ <TR VALIGN=TOP BGCOLOR=WHITE><TD><B>radius_reset</B></TD>
+ <TD>This is called whenever a RADIUS CoA request is
+ received to reset any options to default values before
+ the new values are applied.
+ </TD>
+ <TD>
+ <DL>
+ <DT>t<DD>Tunnel
+ <DT>s<DD>Session
+ </DL>
</TD>
</TR>
<TR VALIGN=TOP BGCOLOR=WHITE><TD><B>control</B></TD>
required.
</TD>
<TD>
- <UL>
- <LI>buf - The raw packet data</LI>
- <LI>l - The raw packet data length</LI>
- <LI>source_ip - Where the request came from</LI>
- <LI>source_port - Where the request came from</LI>
- <LI>response - Allocate a buffer and put your response in here</LI>
- <LI>response_length - Length of response</LI>
- <LI>send_response - true or false whether a response
- should be sent. If you set this to true, you must
- allocate a response buffer.</LI>
- <LI>type - Type of request (see nsctl.c)</LI>
- <LI>id - ID of request</LI>
- <LI>data - I'm really not sure</LI>
- <LI>data_length - Length of data</LI>
- </UL>
+ <DL>
+ <DT>iam_master<DD>Cluster master status
+ <DT>argc<DD>The number of arguments
+ <DT>argv<DD>Arguments
+ <DT>response<DD>Return value: NSCTL_RES_OK or NSCTL_RES_ERR
+ <DT>additional<DD>Extended response text
+ </DL>
</TD>
</TR>
</TABLE>
to sessions that incorrectly authenticate.<P>
Whenever a session provides incorrect authentication, and the
-radius server responds with Auth-Reject, the walled garden module
+RADIUS server responds with Auth-Reject, the walled garden module
(if loaded) will force authentication to succeed, but set the flag
<EM>garden</EM> in the session structure, and adds an iptables rule to
the <B>garden_users</B> chain to force all packets for the session's IP
iptables -t nat -L garden -nvx
</PRE>
+<H2 ID="Filtering">Filtering</H2>
+
+Sessions may be filtered by specifying <B>Filter-Id</B> attributes in
+the RADIUS reply. <I>filter</I>.<B>in</B> specifies that the named
+access-list <I>filter</I> should be applied to traffic from the
+customer, <I>filter</I>.<B>out</B> specifies a list for traffic to the
+customer.
+
<H2 ID="Clustering">Clustering</H2>
An l2tpns cluster consists of of one* or more servers configured with
can use "maximum-paths" (which works for EBGP) and set
<B>as_number</B> to a private value such as 64512.<P>
+<H2 ID="AvoidingFragmentation">Avoiding Fragmentation</H2>
+
+Fragmentation of encapsulated return packets to the LAC may be avoided
+for TCP sessions by adding a firewall rule to clamps the MSS on
+outgoing SYN packets.
+
+The following is appropriate for interfaces with a typical MTU of
+1500:
+
+<pre>
+iptables -A FORWARD -i tun+ -o eth0 \
+ -p tcp --tcp-flags SYN,RST SYN \
+ -m tcpmss --mss 1413:1600 \
+ -j TCPMSS --set-mss 1412
+</pre>
+
<H2 ID="Performance">Performance</H2>
Performance is great.<P>
projects / l2tpns.git / blobdiff