Bump version to v1.5

Most important change is 19c4042 - necessary to support newer Linux kernels.

LICENCE

@@ -1,5 +1,19 @@
-Copyright (c) 2014 Tore Anderson <tore@fud.no>
+Copyright (c) 2014-2019 Tore Anderson <tore@fud.no>
 
-  As long as you retain this notice, you may use this piece of software as
-  you wish. If you like it, and we happen to meet one day, you can buy me
-  a beer in return. If you really like it, make it an IPA.
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

Makefile

@@ -1,20 +1,30 @@
+DESTDIR=
+PREFIX=/usr
+SYSCONFDIR=/etc
+
+APT_GET:=$(shell which apt-get)
+DNF_OR_YUM:=$(shell which dnf || which yum)
+INITCTL:=$(shell which initctl)
+SYSTEMCTL:=$(shell which systemctl)
+TAYGA:=$(shell which tayga)
+
 install:
-	# Install the main script to /usr/sbin
-	install -m0755 clatd /usr/sbin/clatd
+	# Install the main script
+	install -m0755 clatd $(DESTDIR)$(PREFIX)/sbin/clatd
 	# Install manual page if pod2man is installed
-	pod2man --name clatd --center "clatd - a CLAT implementation for Linux" --section 8 README.pod /usr/share/man/man8/clatd.8 && gzip -f9 /usr/share/man/man8/clatd.8 || echo "pod2man is required to generate manual page"
+	pod2man --name clatd --center "clatd - a CLAT implementation for Linux" --section 8 README.pod $(DESTDIR)$(PREFIX)/share/man/man8/clatd.8 && gzip -f9 $(DESTDIR)$(PREFIX)/share/man/man8/clatd.8 || echo "pod2man is required to generate manual page"
 	# Install systemd service file if applicable for this system
-	if test -x /usr/bin/systemctl && test -d "/etc/systemd/system"; then install -m0644 scripts/clatd.systemd /etc/systemd/system/clatd.service && systemctl daemon-reload; fi
-	if test -e "/etc/systemd/system/clatd.service" && test ! -e "/etc/systemd/system/multi-user.target.wants/clatd.service"; then systemctl enable clatd.service; fi
+	if test -x "$(SYSTEMCTL)" && test -d "$(DESTDIR)$(SYSCONFDIR)/systemd/system"; then install -m0644 scripts/clatd.systemd $(DESTDIR)$(SYSCONFDIR)/systemd/system/clatd.service && $(SYSTEMCTL) daemon-reload; fi
+	if test -e "$(DESTDIR)$(SYSCONFDIR)/systemd/system/clatd.service" && test ! -e "$(DESTDIR)$(SYSCONFDIR)/systemd/system/multi-user.target.wants/clatd.service"; then $(SYSTEMCTL) enable clatd.service; fi
 	# Install upstart service file if applicable for this system
-	if test -x /sbin/initctl && test -d "/etc/init"; then install -m0644 scripts/clatd.upstart /etc/init/clatd.conf; fi
+	if test -x "$(INITCTL)" && test -d "$(DESTDIR)$(SYSCONFDIR)/init"; then install -m0644 scripts/clatd.upstart $(DESTDIR)$(SYSCONFDIR)/init/clatd.conf; fi
 	# Install NetworkManager dispatcher script if applicable
-	if test -d /etc/NetworkManager/dispatcher.d; then install -m0755 scripts/clatd.networkmanager /etc/NetworkManager/dispatcher.d/50-clatd; fi
+	if test -d $(DESTDIR)$(SYSCONFDIR)/NetworkManager/dispatcher.d; then install -m0755 scripts/clatd.networkmanager $(DESTDIR)$(SYSCONFDIR)/NetworkManager/dispatcher.d/50-clatd; fi
 
 installdeps:
 	# .deb/apt-get based distros
-	if test -x /usr/bin/apt-get; then apt-get -y install perl-base perl-modules libnet-ip-perl libnet-dns-perl libio-socket-inet6-perl iproute iptables tayga; fi
-	# .rpm/YUM-based distros
-	if test -x /usr/bin/yum; then yum -y install perl perl-Net-IP perl-Net-DNS perl-IO-Socket-INET6 perl-File-Temp iproute iptables; fi
-	# to get TAYGA on .rpm/YUM-based distros, we unfortunately need to install from source
-	if test -x /usr/bin/yum && test ! -x /usr/sbin/tayga; then echo "TAYGA isn't packaged for YUM-based distros, will download and compile the source in 5 seconds (^C interrupts)" && sleep 5 && yum -y install gcc tar wget bzip2 && wget http://www.litech.org/tayga/tayga-0.9.2.tar.bz2 && bzcat tayga-0.9.2.tar.bz2 | tar x && cd tayga-0.9.2 && ./configure --prefix=/usr && make && make install && rm -rf ../tayga-0.9.2.tar.bz2 ../tayga-0.9.2; fi
+	if test -x "$(APT_GET)"; then $(APT_GET) -y install perl-base perl-modules libnet-ip-perl libnet-dns-perl libio-socket-inet6-perl iproute iptables tayga; fi
+	# .rpm/DNF/YUM-based distros
+	if test -x "$(DNF_OR_YUM)"; then $(DNF_OR_YUM) -y install perl perl-Net-IP perl-Net-DNS perl-IO-Socket-INET6 perl-File-Temp iproute iptables; fi
+	# If necessary, try to install the TAYGA .rpm using dnf/yum. It is unfortunately not available in all .rpm based distros (in particular CentOS/RHEL).
+	if test -x "$(DNF_OR_YUM)" && test ! -x "$(TAYGA)"; then $(DNF_OR_YUM) -y install tayga || echo "ERROR: Failed to install TAYGA using dnf/yum, the package is probably not included in your distro. Try enabling the EPEL repo <URL: https://fedoraproject.org/wiki/EPEL> and try again, or install TAYGA <URL: http://www.litech.org/tayga> directly from source."; exit 1; fi

README.pod

@@ -1,6 +1,6 @@
 =head1 NAME
 
-B<clatd> - a CLAT / SIIT-DC Host Agent implementation for Linux
+B<clatd> - a CLAT / SIIT-DC Edge Relay implementation for Linux
 
 =head1 DESCRIPTION
 
@@ -13,12 +13,12 @@ local applications on the host requires actual IPv4 connectivity or cannot
 make use of DNS64 (for example because they use legacy AF_INET socket calls,
 or if they are simply not using DNS64).
 
-It may also be used to implement an SIIT-DC Host Agent as defined by
-I<I-D.anderson-v6ops-siit-dc-2xlat>. In this scenario, the PLAT is a SIIT-DC
-Gateway (see I<I-D.anderson-v6ops-siit-dc>) instead of a Stateful NAT64 (see
-I<RFC6146>). When used as a SIIT-DC Host Agent, you will probably want to
-manually configure the settings I<clat-v4-addr>, I<clat-v6-addr>, and
-I<plat-prefix> to mirror the SIIT-DC Gateway's configuration.
+B<clatd> may also be used to implement an SIIT-DC Edge Relay as described in
+I<RFC 7756>. In this scenario, the PLAT is in reality a SIIT-DC Border Relay
+(see I<RFC 7755>) instead of a Stateful NAT64 (see I<RFC6146>). When used as a
+SIIT-DC Edge Relay, you will probably want to manually configure the settings
+I<clat-v4-addr>, I<clat-v6-addr>, and I<plat-prefix> to mirror the SIIT-DC
+Border Relay's configuration.
 
 It relies on the software package TAYGA by Nathan Lutchansky for the actual
 translation of packets between IPv4 and IPv6 (I<RFC 6145>) TAYGA may be
@@ -87,21 +87,21 @@ of B<clatd> and its dependencies:
 
 This will install B<clatd> to /usr/sbin, plus install systemd, upstart, and/or
 NetworkManager scripts if your distribution appears to be using them, and
-install all the dependencies. Note that TAYGA isn't available in RPM format,
-so on RedHat/Fedora the installdeps target will install gcc and attempt to
-compile TAYGA from source.
+install all the dependencies. Note that TAYGA isn't available in all RPM-based
+distros (in particular RHEL and its clones). It is however available in EPEL
+(see L<https://fedoraproject.org/wiki/EPEL>).
 
 =head1 CONFIGURATION
 
 B<clatd> is designed to be able to run without any user-supplied configuration
-in most cases. However, user-specified onfiguration settings may be added to
+in most cases. However, user-specified configuration settings may be added to
 the configuration file, the path to which may be given on the command line
 using the I<-c> option, or if it is not, the default location
 I</etc/clatd.conf> is used. Configuration settings may also be given directly
 on the command line when starting B<clatd>, which takes precedence over settings
 in the configuration file.
 
-Settings are of the form B<key=value>. A list of recogniced keys and their
+Settings are of the form B<key=value>. A list of recognised keys and their
 possible values follow below:
 
 =over
@@ -119,6 +119,57 @@ Set this to 1 to get debugging output from B<clatd>, or 2 to get even more of
 the stuff. These are the equivalent of providing the command line option I<-d>
 the specified number of times.
 
+=item B<script-up=string> (no default)
+
+Specify a custom script to be run when B<clatd> is starting up. The invocation
+of this script is the last thing that happens before TAYGA starts up, so all
+the preparations have been completed at that point (i.e., the B<clat-dev>
+exists and has routing/addressing configured, forwarding has been enabled, and
+so on).
+
+The script is run by the system shell, so you can do everything you could in an
+interactive shell: run multiple commands by separating them by semi-colon or
+double ampersands, use standard if/else statements, use variable substitutions,
+redirect output to files, set up command pipelines, and so on. However it must
+all be on one line, so if you want to do complex things or use some other
+programming language it's probably better to put the script itself in a
+separate executable file and just make B<script-up> invoke that file instead.
+
+If the script returns a nonzero exit status, this is considered a fatal error,
+and B<clatd> will abort. This can be prevented by appending I<|| true> at the
+end of the script.
+
+All of B<clatd>'s configuration settings are available as standard variables in
+the script's environment (hyphens are replaced with underscores).
+
+Logging or debug messages from the script may simply be sent to stdout, where
+it will be picked up by the init system along with B<clatd>'s own output. The
+script may of course consult the I<$quiet> and I<$debug> environment variables
+in order to determine how much output is appropriate.
+
+The script should not be enclosed in quotes in the configuration file (even
+though it contains whitespace). For example:
+
+B<script-up=echo `date -Ins`: clatd started on $clat_dev | tee -a ~/clatd.log>
+
+If on the other hand you want to supply a B<script-up> containing whitespace
+directly B<clatd>'s command line, quoting is required in order to prevent the
+shell from splitting it up and into multiple command line arguments. For
+example:
+
+B<clatd 'script-up=ip route add 192.0.2.0/24 dev $clat_dev || true'>
+
+=item B<script-down=string> (no default)
+
+This works exactly the same as B<script-up>, only that this script is run right
+after TAYGA has exited, before the clean-up process of restoring any settings
+that were changed.
+
+An unsuccessful exit code from B<script-down> will cause B<clatd> to exit
+unsuccessfully too. Beyond that an unsuccessful exit won't change anything,
+because B<script-down> is invoked at a point in time where the only thing left
+for B<clatd> to do is to clean up after itself and exit anyway.
+
 =item B<clat-dev=string> (default: I<clat>)
 
 The name of the network device used by the CLAT. There should be no reason to
@@ -132,21 +183,20 @@ will bind to this address when communicating with external IPv4 destinations.
 In a standard 464XLAT environment with a stateful NAT64 serving as the PLAT,
 there should be no need to change the default.
 
-When using B<clatd> as an SIIT-DC Host Agent (cf.
-I-D.draft-anderson-v6ops-siit-dc-2xlat), you will want to set this to the
-IPv4 Service Address configured in the SIIT-DC Gateway. This way, local
-applications can correctly identify which public address they'll be using on
-the IPv4 internet, and will be able to provide fully functional references to
-it in application-level payload, and so on.
+When using B<clatd> as an SIIT-DC Edge Relay (I<RFC 7756>), you will want to
+set this to the IPv4 Service Address configured in the SIIT-DC Border Relay.
+This way, local applications can correctly identify which public address
+they'll be using on the IPv4 internet, and will be able to provide fully
+functional references to it in application-level payload, and so on.
 
 The default address is one from I<RFC 7335>.
 
 =item B<clat-v6-addr=ipv6-address> (default: auto-generated)
 
 The IPv6 address of the CLAT. Traffic to/from the B<clat-v4-addr> will be
-translated into this address. When using B<clatd> as an SIIT-DC Host Agent,
-you will want to set this to the IPv6 address in the Static Address Mapping
-configured in the SIIT-DC Gateway.
+translated into this address. When using B<clatd> as an SIIT-DC Edge Relay, you
+will want to set this to the same IPv6 address in the Explicit Address Mapping
+configured in the SIIT-DC Border Relay.
 
 By default, B<clatd> will attempt to figure out which network device will be
 used for traffic towards the PLAT, see if there is any SLAAC-based globally
@@ -230,7 +280,7 @@ DNS64 answers using the method in I<RFC 7050>.
 Controls whether or not B<clatd> should add a Proxy-ND entry for the CLAT IPv6
 address on the network device facing the PLAT. This is probably necessary
 on Ethernet networks (otherwise the upstream IPv6 router won't know where to
-send packets to the CLAT's IPv6 adderss), but likely not necessary on
+send packets to the CLAT's IPv6 address), but likely not necessary on
 point-to-point links like PPP or 3GPP mobile broadband, as in those cases
 IPv6 ND isn't used. However it doesn't hurt to add Proxy-ND entries in that
 case, either.
@@ -267,6 +317,9 @@ system has IPv4 connectivity, disable this setting. You may instead use the
 B<v4-defaultroute-enable> and B<v4-defaultroute-metric> settings to prevent
 B<clatd> from interfering with native IPv4 connectivity.
 
+Note that enabling B<v4-defaultroute-replace> will override
+B<v4-conncheck-enable> and unconditionally disable IPv4 connectivity checking.
+
 =item B<v4-conncheck-delay=seconds> (default: I<10>)
 
 When performing an IPv4 connectivity check, wait this number of seconds
@@ -287,6 +340,23 @@ an environment where native IPv4 connectivity is also present, you might want
 to disable this and instead control manually which IPv4 destinations is
 reached through the CLAT and which are not.
 
+=item B<v4-defaultroute-replace=bool> (default: I<no>)
+
+Instructs B<clatd> to remove any pre-existing IPv4 default routes, replacing it
+with one pointing to the CLAT (assuming B<v4-defaultroute-enable> is I<yes>).
+The replacement is temporary, any pre-existing routes that were removed will be
+restored when B<clatd> is shutting down.
+
+Note that nothing prevents software like a connection manager or a DHCPv4
+client daemon from re-adding any replaced routes while B<clatd> is running.
+
+If you enable B<v4-defaultroute-replace> while at the same time disabling
+B<v4-defaultroute-enable>, B<clatd> will remove any pre-existing IPv4 default
+routes but not add any of its own.
+
+Setting B<v4-defaultroute-replace> to I<yes> will disable the IPv4 connectivity
+check.
+
 =item B<v4-defaultroute-metric=integer> (default: I<2048>)
 
 The metric of the IPv4 default route pointing to the CLAT. The default is
@@ -307,6 +377,17 @@ If you know that the IPv6 Path MTU between the host and the PLAT is larger
 than 1280, you may increase this, but then you should also recompile TAYGA
 with a larger B<ipv6_offlink_mtu> setting in I<conffile.c>.
 
+=item B<v4-defaultroute-advmss=integer> (default: B<v4-defaultroute-mtu> - 40)
+
+The "advmss" value assigned to the the default route potining to the CLAT. This
+controls the advertised TCP MSS value for TCP connections made through the
+CLAT.
+
+You should normally not need to set this. By default the value is calculated by
+taking the value of B<v4-defaultroute-mtu> and substracting 40 (20 bytes for
+the IPv4 header + 20 bytes for the TCP header). If B<v4-defaultroute-mtu> is
+unset or 0, there is no default.
+
 =back
 
 =head1 LIMITATIONS
@@ -331,18 +412,31 @@ configuration file) when reporting a bug.
 
 =head1 LICENCE
 
-Copyright (c) 2014 Tore Anderson <tore@fud.no>
+Copyright (c) 2014-2019 Tore Anderson <tore@fud.no>
 
-As long as you retain this notice, you may use this piece of software as
-you wish. If you like it, and we happen to meet one day, you can buy me
-a beer in return. If you really like it, make it an IPA.
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
 
 =head1 SEE ALSO
 
 ip(8), ip6tables(8), tayga(8), tayga.conf(5)
 
-RFC 6052, RFC 6145, RFC 6146, RFC 6877, RFC 7050, RFC 7335
-
-I-D.anderson-v6ops-siit-dc, I-D.anderson-v6ops-siit-dc-2xlat
+RFC 6052, RFC 6145, RFC 6146, RFC 6877, RFC 7050, RFC 7335 RFC 7755, RFC 7756,
+RFC 7757
 
 =cut

clatd

@@ -1,10 +1,24 @@
 #! /usr/bin/perl -w
 #
-# Copyright (c) 2014 Tore Anderson <tore@fud.no>
+# Copyright (c) 2014-2019 Tore Anderson <tore@fud.no>
 #
-#   As long as you retain this notice, you may use this piece of software as
-#   you wish. If you like it, and we happen to meet one day, you can buy me
-#   a beer in return. If you really like it, make it an IPA.
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
 #
 # See the file 'README.pod' in the source distribution or the manual page
 # clatd(8) for more information.
@@ -12,7 +26,7 @@
 use strict;
 use Net::IP;
 
-my $VERSION = "1.2";
+my $VERSION = "1.5";
 
 #
 # Populate the global config hash with the default values
@@ -20,6 +34,8 @@ my $VERSION = "1.2";
 my %CFG;
 $CFG{"quiet"} = 0;			# suppress normal output
 $CFG{"debug"} = 0;			# debugging output level
+$CFG{"script-up"} = undef;              # sh script to run when starting up
+$CFG{"script-down"} = undef;            # sh script to run when shutting down
 $CFG{"clat-dev"} = "clat";		# TUN interface name to use
 $CFG{"clat-v4-addr"} = "192.0.0.1";	# from RFC 7335
 $CFG{"clat-v6-addr"} = undef;		# derive from existing SLAAC addr
@@ -37,8 +53,10 @@ $CFG{"tayga-v4-addr"} = "192.0.0.2";	# from RFC 7335
 $CFG{"v4-conncheck-enable"} = 1;	# exit if there's already a defroute
 $CFG{"v4-conncheck-delay"} = 10;	# seconds before checking for v4 conn.
 $CFG{"v4-defaultroute-enable"} = 1;	# add a v4 defaultroute via the CLAT?
+$CFG{"v4-defaultroute-replace"} = 0;	# replace existing v4 defaultroute?
 $CFG{"v4-defaultroute-metric"} = 2048;	# metric for the IPv4 defaultroute
 $CFG{"v4-defaultroute-mtu"} = 1260;	# MTU for the IPv4 defaultroute
+$CFG{"v4-defaultroute-advmss"} = 0;	# TCP MSS for the IPv4 defaultroute
 
 
 #
@@ -69,18 +87,17 @@ sub err {
 #
 sub cmd {
   my $msgsub = shift;
-  my $command = shift;
-  my @cmdline = @_;
+  my @cmd = @_;
 
-  d("cmd($command @cmdline)");
+  d("cmd(@cmd)");
 
-  if(system($command, @cmdline)) {
+  if(system(@cmd)) {
     if($? == -1) {
-      &{$msgsub}("cmd($command @cmdline) failed to execute");
+      &{$msgsub}("cmd(@cmd) failed to execute");
     } elsif($? & 127) {
-      &{$msgsub}("cmd($command @cmdline) died with signal ", ($? & 127));
+      &{$msgsub}("cmd(@cmd) died with signal ", ($? & 127));
     } else {
-      &{$msgsub}("cmd($command @cmdline) returned ", ($? >> 127));
+      &{$msgsub}("cmd(@cmd) returned ", ($? >> 127));
     }
   }
   return $?;
@@ -135,7 +152,7 @@ sub cfgbool {
 #
 sub cfgint {
   my ($key) = @_;
-  d2("cfgstr($key)");
+  d2("cfgint($key)");
   if(!exists($CFG{$key})) {
     err("key '$key' doesn't exist in config hash");
   }
@@ -150,7 +167,7 @@ sub cfgint {
 #
 sub cfg {
   my ($key) = @_;
-  d2("cfgstr($key)");
+  d2("cfg($key)");
   if(!exists($CFG{$key})) {
     err("key '$key' doesn't exist in config hash");
   }
@@ -202,9 +219,9 @@ sub sysctl {
 
 #
 # Look for either of the WKAs for ipv4only.arpa (192.0.0.170 and .171) in an
-# IPv6 address at all of the locations RFC 6052 says it can occur. If it's
-# present at any of those locations (but no more than once), return the
-# inferred translation prefix.
+# IPv6 address at all of the locations RFC 6052 says it can occur, starting at
+# the longest prefix length. If it's present at any of those locations, return
+# the inferred translation prefix.
 #
 sub find_rfc7050_wka {
   my $AAAA = shift;
@@ -231,7 +248,7 @@ sub find_rfc7050_wka {
 
   my $discovered_pfx_len;
 
-  for my $len (keys(%rfc6052table)) {
+  outer: for my $len (sort {$b <=> $a} keys(%rfc6052table)) {
     d2("Looking for Well-Known Addresses at prefix length /$len");
     my $maskedip = $ip->intip();
     my $mask = Net::IP->new($rfc6052table{"$len"}{"mask"}, 6);
@@ -252,13 +269,9 @@ sub find_rfc7050_wka {
       }
 
       if($maskedip == $wkaint->intip) {
-        if($discovered_pfx_len) {
-          w("Found WKA at two locations in ", $ip->sort,
-            "(/$discovered_pfx_len and /$len) - ignoring");
-          return;
-        }
         d2("Found it!");
         $discovered_pfx_len = $len;
+        last outer;
       } else {
         d2("Didn't find it");
       }
@@ -380,6 +393,7 @@ sub get_plat_dev {
   if(!$plat_prefix) {
     err("get_plat_dev(): No PLAT prefix to work with");
   }
+  $plat_prefix =~ s|/\d+$||;
   open(my $fd, '-|', cfg("cmd-ip"), qw(-6 route get), $plat_prefix)
     or err("get_plat_dev(): 'ip -6 route get $plat_prefix' failed to execute");
   while(<$fd>) {
@@ -569,6 +583,7 @@ my @cleanup_accept_ra_sysctls;		# accept_ra sysctls to be reset to '1'
 my $cleanup_zero_proxynd_sysctl;	# zero proxy_ndp sysctl if set
 my $cleanup_remove_proxynd_entry,	# true if having added proxynd entry
 my $cleanup_remove_ip6tables_rules;	# true if having added ip6tables rules
+my @cleanup_restore_v4_defaultroutes;   # temporarily replaced defaultroutes
 
 sub cleanup_and_exit {
   my $exitcode = shift;
@@ -608,6 +623,10 @@ sub cleanup_and_exit {
     cmd(\&w, cfg("cmd-ip6tables"), qw(-D FORWARD -i), cfg("plat-dev"),
         "-o", cfg("clat-dev"), qw(-j ACCEPT));
   }
+  for my $rt (@cleanup_restore_v4_defaultroutes) {
+    d("Cleanup: Restoring temporarily replaced IPv4 default route");
+    cmd(\&w, cfg("cmd-ip"), qw(-4 route add), @{$rt});
+  }
 
   exit($exitcode);
 }
@@ -643,8 +662,8 @@ for (my $i = 0; $i < @ARGV;) {
     next;
   } elsif($ARGV[$i] =~ /^(-h|--help)$/) {
     print <<"EOF";
-clatd v$VERSION - a 464XLAT (RFC 6877) CLAT and SIIT-DC Host Agent
-             (I-D.anderson-v6ops-siit-dc-2xlat) implementation for Linux
+clatd v$VERSION - a 464XLAT (RFC 6877) CLAT and SIIT-DC Edge Relay
+             (RFC 7756) implementation for Linux
 EOF
     print "\n";
     print "  Usage:    clatd [-q] [-d [-d]] [-c config-file] ",
@@ -725,12 +744,15 @@ p("Using CLAT IPv6 address: ", $CFG{"clat-v6-addr"});
 if(!defined($CFG{"ip6tables-enable"})) {
   $CFG{"ip6tables-enable"} = -e "/sys/module/ip6table_filter" ? 1 : 0;
 }
+if(!$CFG{"v4-defaultroute-advmss"} and cfgint("v4-defaultroute-mtu")) {
+  $CFG{"v4-defaultroute-advmss"} = $CFG{"v4-defaultroute-mtu"} - 40;
+}
 
 #
 # Step 1: Detect if there is an IPv4 default route on the system from before.
 # If so we have no need for 464XLAT, and we can just exit straight away
 #
-if(cfgbool("v4-conncheck-enable")) {
+if(cfgbool("v4-conncheck-enable") and !cfgbool("v4-defaultroute-replace")) {
   my $delay = cfgint("v4-conncheck-delay");
   p("Checking if this system already has IPv4 connectivity ",
     $delay ? "in $delay sec(s)" : "now");
@@ -845,18 +867,44 @@ cmd(\&err, cfg("cmd-ip"), qw(-4 address add), cfg("clat-v4-addr"),
     "dev", cfg("clat-dev"));
 cmd(\&err, cfg("cmd-ip"), qw(-6 route add), cfg("clat-v6-addr"),
     "dev", cfg("clat-dev"));
+if(cfgbool("v4-defaultroute-replace")) {
+  open(my $fd, '-|', cfg("cmd-ip"), qw(-4 route show default))
+    or err("'ip -4 route show default' failed to execute");
+  while(<$fd>) {
+    my @rt = split(/\s+/, $_);
+    d("Replacing pre-existing IPv4 default route: @rt");
+    cmd(\&err, cfg("cmd-ip"), qw(-4 route del), @rt);
+    push(@cleanup_restore_v4_defaultroutes, \@rt);
+  }
+  close($fd) or err("'ip -4 route show default' failed");
+}
 if(cfgbool("v4-defaultroute-enable")) {
   my @cmdline = (qw(-4 route add default dev), cfg("clat-dev"));
   if(cfgint("v4-defaultroute-metric")) {
     push(@cmdline, ("metric", cfgint("v4-defaultroute-metric")))
   }
   if(cfgint("v4-defaultroute-mtu")) {
-    push(@cmdline, ("mtu", cfgint("v4-defaultroute-mtu")))
+    push(@cmdline, ("mtu", cfgint("v4-defaultroute-mtu")));
+  }
+  if(cfgint("v4-defaultroute-advmss")) {
+    push(@cmdline, ("advmss", cfgint("v4-defaultroute-advmss")));
   }
   p("Adding IPv4 default route via the CLAT");
   cmd(\&err, cfg("cmd-ip"), @cmdline);
 }
 
+# Inject %CFG into %ENV and then run the up script
+for my $key (sort keys(%CFG)) {
+  my $var = $key;
+  $var =~ y/-/_/;
+  d2(sprintf("Script env: %s=%s", $key, $CFG{$key} || ''));
+  $ENV{$var} = $CFG{$key};
+}
+if(cfg("script-up")) {
+  d("Running custom startup script: ", cfg("script-up"));
+  cmd(\&err, cfg("script-up"));
+}
+
 #
 # All preparation done! We can now start TAYGA, which will handle the actual
 # translation of IP packets.
@@ -877,6 +925,11 @@ $SIG{'INT'} = 'DEFAULT';
 $SIG{'TERM'} = 'DEFAULT';
 
 #
-# TAYGA exited, probably because we're shutting down. Cleanup and exit.
+# TAYGA exited, probably because we're shutting down. Run the down script, then
+# cleanup and exit.
 #
+if(cfg("script-down")) {
+  d("Running custom shutdown script: ", cfg("script-down"));
+  cmd(\&err, cfg("script-down"));
+}
 cleanup_and_exit(0);

scripts/clatd.networkmanager

@@ -7,6 +7,18 @@
 # Written by Tore Anderson <tore@fud.no>
 #
 
+# Newer NetworkManager versions will run the dispatcher scripts once
+# a new unmanaged interface shows up, including the 'clat' interface
+# created by clatd/TAYGA. So if we're being called due to our own
+# interface showing up, do nothing, otherwise we will end up
+# committing suicide from the restarts below
+[ "$DEVICE_IFACE" = "clat" ] && exit 0
+
+# We're only acting on interface "up" or "down" events. NM will run the
+# dispatcher scripts for other events we're not interested in, like the
+# hostname being set or a DHCP lease being renewed. Ignore those.
+[ "$2" != "up" ] && [ "$2" != "down" ] && exit 0
+
 # We simply restart clatd in all situations, as no matter if an interface
 # goes up or down, it may mean that the PLAT device changes, it may mean
 # native IPv4 appearing or disappearing, or it may mean that DNS64 became
@@ -14,8 +26,8 @@
 # start from scratch than to figure out if a restart is truly necessary
 
 # systemd-based distros
-if test -x /usr/bin/systemctl; then
-  /usr/bin/systemctl restart clatd.service
+if which systemctl &> /dev/null; then
+  systemctl restart clatd.service
 fi
 
 # upstart-based distros