forked from extern/shorewall_code
315d8a92b4
git-svn-id: https://shorewall.svn.sourceforge.net/svnroot/shorewall/trunk@3399 fbd18981-670d-0410-9b5c-8dc0c1a9a2bb
275 lines
10 KiB
Plaintext
Executable File
275 lines
10 KiB
Plaintext
Executable File
Shorewall 3.1.4
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Note to users upgrading from Shorewall 2.x or 3.0
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Most problems associated with upgrades come from two causes:
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- The user didn't read and follow the migration considerations in these
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release notes.
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- The user mis-handled the /etc/shorewall/shorewall.conf file during
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upgrade. Shorewall is designed to allow the default behavior of
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the product to evolve over time. To make this possible, the design
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assumes that you will not replace your current shorewall.conf file
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during upgrades. If you feel absolutely compelled to have the latest
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comments and options in your shorewall.conf then you must proceed
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carefully.
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While you are at it, if you have a file named /etc/shorewall/rfc1918 then
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please check that file. If it has addresses listed that are NOT in one of
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these three ranges, then please rename the file to
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/etc/shorewall/rfc1918.old.
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10.0.0.0 - 10.255.255.255
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172.16.0.0 - 172.31.255.255
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192.168.0.0 - 192.168.255.255
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Please see the "Migration Considerations" below for additional upgrade
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information.
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Problems Corrected in 3.1.4
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1) "shorewall check" generated an error if there were entries in
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/etc/shorewall/massq.
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2) Bridging now works.
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3) The handling of the QUEUE target in the ESTABLISHED section has been
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corrected. Previously, the "--syn" option was being added unconditionally
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to rules with the QUEUE target with the result that no TCP packets in the
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ESTABLISHED state would be sent to QUEUE.
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New Features added in 3.1.4
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1) The /etc/shorewall/maclist file has a new column layout. The first column
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is now DISPOSITION. This column determines what to do with matching
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packets and can have the value ACCEPT or DROP (if MACLIST_TABLE=filter, it
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can also contain REJECT). This change is upward compatible so your existing
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maclist file can still be used.
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ACCEPT, DROP and REJECT may be optionally followed by a log level to
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cause the packet to be logged.
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2) Shorewall has always been very noisy (lots of messages). No more.
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You set the default level of verbosity using the VERBOSITY option in
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shorewall.conf. If you don't set it (as would be the case of you use your
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old shorewall.conf file) then VERBOSITY defaults to a value of 2 which is
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the old default. A value of 1 suppresses some of the output (like the old
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-q option did) while a value of 0 makes Shorewall almost silent.
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The value specified in the 3.2 shorewall.conf is 1. So you can make
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Shorewall as verbose as previously using a single -v and you can make it
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silent by using a single -q.
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If the default is set at 2, you can still make a command silent by using
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two "q"s (e.g., shorewall -qq restart).
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In summary, each "q" subtracts one from VERBOSITY while each "v" adds one
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to VERBOSITY.
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The "shorewall show log", "shorewall logwatch" and "shorewall dump"
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commands require VERBOSE to be greater than or equal to 3 to display MAC
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addresses.This is consistent with the previous implementation which
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required a single -v to enable MAC display but means that if you set
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VERBOSITY=0 in shorewall.conf, then you will need to include -vvv in
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commands that display log records in order to have MACs displayed.
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3) Shorewall now implements 'start' and 'restart' using a "compile and
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go" approach. See the details under the first new feature below.
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4) The "-p" option to the 'compile' command is gone. Generation of a
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complete program is now the default.
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Migration Considerations:
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None.
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New Features:
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1) A new 'shorewall generate' command has been added.
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shorewall generate [ -v ] [ -q ] [ -e ] [ <config directory> ] <script
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file>
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where:
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-v and -q are described elsewhere in this document.
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-e Generates an error if the configuration uses
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an option that would prevent the generated
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script from running on a system other than
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where the 'generate' command is running (see
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additional consideration a) below).
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Also allows the generated script to run
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on a system without Shorewall installed.
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<config directory> Is an optional directory to be searched for
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configuration files prior to those listed
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in CONFIG_DIR in
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/etc/shorewall/shorewall.conf.
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<script file> Is the name of the output file.
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The 'generate' command processes the configuration and writes a script
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file which may then be executed (either directly or using the
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'shorewall restore' command) to configure the firewall.
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'compile' is a synonym for 'generate':
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shorewall compile [ -v ] [ -q ] [ -e ] [ <config directory> ] <script file>
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The generated script contains error checking and will terminate if an
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important command fails. Before terminating:
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a) The script will check for the existence of the restore script
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specified by the RESTOREFILE variable in shorewall.conf. If that
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restore script exists, it is executed.
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b) If the restore script doesn't exist but Shorewall appears to be
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installed on the system, an "/sbin/shorewall stop" command is executed.
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Some additional considerations:
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a) It is possible to run 'generate' ('compile') on one system and then
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run the generated script on another system but there are certain
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limitations.
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1) The same version of Shorewall must be running on the remote system
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unless you use the "-e" option when you compile the script.
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2) The 'detectnets' interface option is not allowed.
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b) If you have extension scripts, they may need modification. Some of
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the scripts will be run at compile time, rather than when the
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generated script is executed. The standard functions like
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'run_iptables' and 'log_rule_limit' will write the iptables command
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to the script file rather than executing the command. As always, you
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can check $COMMAND to determine which shorewall command is being
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executed.
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Extension Scripts that are run at compile time rather than at
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run-time are:
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- params
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- init
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- continue
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- initdone
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- start
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- started
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- All scripts associated with a given chain such as Action
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chains
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If you need to interject run-time code into the generated script then
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you need to write it to file descriptor 3. Here is an example of creating
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tap device tap0 and adding it to bridge xenbr0; the text will be indented
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to line up with the surrounding text:
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cat >&3 << __EOF__
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${INDENT}if ! qt /sbin/ip link ls dev tap0; then
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${INDENT} /usr/sbin/openvpn --mktun --dev tap0
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${INDENT} /sbin/ip link set dev tap0 up
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${INDENT} /sbin/brctl addif xenbr0 tap0
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${INDENT}fi
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__EOF__
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This results in the following code in the script:
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if ! qt /sbin/ip link ls dev tap0; then
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/usr/sbin/openvpn --mktun --dev tap0
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/sbin/ip link set dev tap0 up
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/sbin/brctl addif xenbr0 tap0
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fi
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(Yes -- there is an extra blank line at the end)
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If you need to expand variables in the generated text, be sure to escape
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the '$' symbol.
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Example:
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cat >&3 << __EOF__
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${INDENT}addr=\$(ip -f inet addr show $interface 2> /dev/null | grep inet | head -n1)
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${INDENT}if [ -n "\$addr" ]; then
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${INDENT} addr=\$(echo \$addr | sed 's/inet //;s/\/.*//;s/ peer.*//')
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${INDENT} for network in 10.0.0.0/8 176.16.0.0/12 192.168.0.0/16; do
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${INDENT} if in_network \$addr \$network; then
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${INDENT} startup_error "The 'norfc1918' option has been specified on an interface with an RFC 1918 address. Interface:$interface"
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${INDENT} fi
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${INDENT} done
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${INDENT}fi
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__EOF__
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In addition to 'generate', a 'shorewall reload' command has been added.
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shorewall reload [ -v ] [ -q ] [ <config directory> ]
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where -v, -q and <config directory> are as above.
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The 'reload' command creates a script using 'generate' and if there are
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no errors, it then restores that script. It is equivalent to:
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if shorewall generate /var/lib/shorewall/.reload; then
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restore .reload;
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fi
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The advantage of using reload over restart is that reload results in new
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connections being dropped for a much shorter time. Here are the results
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of tests that I conducted on my own firewall:
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A) shorewall restart (Shorewall 3.0.4)
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real 0m17.540s
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user 0m5.956s
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sys 0m10.737s
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B) ./foo restart # foo created using "shorewall compile"
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real 0m3.505s
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user 0m1.332s
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sys 0m2.164s
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C) shorewall restore (Shorewall 3.0.4) # Restores from file generated by
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# "shorewall save"
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real 0m1.164s
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user 0m0.556s
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sys 0m0.608s
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The time difference between B and C reflects the difference between
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"iptables-restore" and multiple executions of "iptables". The system is
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a 1.4Ghz Celeron with 512MB RAM.
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Compilation generates a complete program. This program is suitable for
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installation into /etc/init.d and, when generated with the "-e" option,
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can serve as your firewall on a system that doesn't even have Shorewall
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installed.
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The program supports the following commands:
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<program> [ -q ] [ -v ] [ -n ] start
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<program> [ -q ] [ -v ] [ -n ] stop
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<program> [ -q ] [ -v ] [ -n ] clear
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<program> [ -q ] [ -v ] [ -n ] {restart|reload}
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<program> [ -q ] [ -v ] [ -n ] status
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<program> [ -q ] [ -v ] [ -n ] version
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The "shorewall start" and "shorewall restart" commands have been
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rewritten to use compilation. They both compile a temporary program
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then run it. This results in a slightly longer elapsed time than the
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similar commands required under earlier versions of Shorewall but new
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connections are blocked for a much smaller percentage of that time as
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shown by the numbers above. Under Shorewall 3.1.4, "shorewall restart"
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takes roughly 20.5 seconds on my firewall:
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real 0m20.206s
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user 0m7.412s
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sys 0m12.773s
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As a final part of this change, the "check" command now compiles the
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current configuration then discards the generated script. So "check"
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performs all of the same checks that compile does. Note that there is
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still no guarantee that the generated script won't encounter run-time
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errors.
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