doc: deduplicate extension descriptions into a new manpage

iptables.8 and ip6tables.8 had pretty much the same content, with a few
protocol-specific deviations here and there. Not only did that bloat the
manpages, but it also made it harder to spot differences. Separate out
the extension descriptions into a new manpage, which conveniently
features differences next to one another (cf. REJECT).

Signed-off-by: Jan Engelhardt <jengelh@inai.de>

5 files changed, 46 insertions, 40 deletions

diff --git a/iptables/.gitignore b/iptables/.gitignore
index 5a089376..4fc63aa4 100644
--- a/iptables/.gitignore
+++ b/iptables/.gitignore
@@ -5,6 +5,7 @@
 /ip6tables-static
 /iptables
 /iptables.8
+/iptables-extensions.8
 /iptables-save
 /iptables-restore
 /iptables-static
diff --git a/iptables/Makefile.am b/iptables/Makefile.am
index bdd4da11..61e78db9 100644
--- a/iptables/Makefile.am
+++ b/iptables/Makefile.am
@@ -27,7 +27,7 @@ xtables_multi_LDADD   += ../libxtables/libxtables.la -lm
 sbin_PROGRAMS    = xtables-multi
 man_MANS         = iptables.8 iptables-restore.8 iptables-save.8 \
                    iptables-xml.1 ip6tables.8 ip6tables-restore.8 \
-                   ip6tables-save.8
+                   ip6tables-save.8 iptables-extensions.8
 CLEANFILES       = iptables.8 ip6tables.8
 
 vx_bin_links   = iptables-xml
@@ -38,11 +38,17 @@ if ENABLE_IPV6
 v6_sbin_links  = ip6tables ip6tables-restore ip6tables-save
 endif
 
-iptables.8: ${srcdir}/iptables.8.in ../extensions/matches4.man ../extensions/targets4.man
-	${AM_VERBOSE_GEN} sed -e 's/@PACKAGE_AND_VERSION@/${PACKAGE} ${PACKAGE_VERSION}/g' -e '/@MATCH@/ r ../extensions/matches4.man' -e '/@TARGET@/ r ../extensions/targets4.man' $< >$@;
+iptables.8: ${srcdir}/iptables.8.in
+	${AM_VERBOSE_GEN} sed -e 's/@PACKAGE_AND_VERSION@/${PACKAGE} ${PACKAGE_VERSION}/g' $< >$@;
 
-ip6tables.8: ${srcdir}/ip6tables.8.in ../extensions/matches6.man ../extensions/targets6.man
-	${AM_VERBOSE_GEN} sed -e 's/@PACKAGE_AND_VERSION@/${PACKAGE} ${PACKAGE_VERSION}/g' -e '/@MATCH@/ r ../extensions/matches6.man' -e '/@TARGET@/ r ../extensions/targets6.man' $< >$@;
+ip6tables.8: ${srcdir}/ip6tables.8.in
+	${AM_VERBOSE_GEN} sed -e 's/@PACKAGE_AND_VERSION@/${PACKAGE} ${PACKAGE_VERSION}/g' $< >$@;
+
+iptables-extensions.8: ${srcdir}/iptables-extensions.8.in ../extensions/matches.man ../extensions/targets.man
+	${AM_VERBOSE_GEN} sed -e \
+		's/@PACKAGE_AND_VERSION@/${PACKAGE} ${PACKAGE_VERSION}/g' \
+		-e '/@MATCH@/ r ../extensions/matches.man' \
+		-e '/@TARGET@/ r ../extensions/targets.man' $< >$@;
 
 pkgconfig_DATA = xtables.pc
 
diff --git a/iptables/ip6tables.8.in b/iptables/ip6tables.8.in
index 65f38646..edd092d7 100644
--- a/iptables/ip6tables.8.in
+++ b/iptables/ip6tables.8.in
@@ -362,23 +362,8 @@ When adding or inserting rules into a chain, use \fIcommand\fP
 to load any necessary modules (targets, match extensions, etc).
 .SH MATCH EXTENSIONS
 .PP
-ip6tables can use extended packet matching modules
-with the \fB\-m\fP or \fB\-\-match\fP
-options, followed by the matching module name; after these, various
-extra command line options become available, depending on the specific
-module.  You can specify multiple extended match modules in one line,
-and you can use the \fB\-h\fP or \fB\-\-help\fP
-options after the module has been specified to receive help specific
-to that module.
-.PP
-If the \fB\-p\fP or \fB\-\-protocol\fP was specified and if and only if an
-unknown option is encountered, ip6tables will try load a match module of the
-same name as the protocol, to try making the option available.
-.\" @MATCH@
-.SH TARGET EXTENSIONS
-ip6tables can use extended target modules: the following are included
-in the standard distribution.
-.\" @TARGET@
+iptables can use extended packet matching and target modules.
+A list of these is available in the \fBiptables\-extensions\fP(8) manpage.
 .SH DIAGNOSTICS
 Various error messages are printed to standard error.  The exit code
 is 0 for correct functioning.  Errors which appear to be caused by
@@ -405,6 +390,7 @@ There are several other changes in ip6tables.
 \fBip6tables\-save\fP(8),
 \fBip6tables\-restore\fP(8),
 \fBiptables\fP(8),
+\fBiptables\-extensions\fP(8),
 \fBiptables\-save\fP(8),
 \fBiptables\-restore\fP(8),
 \fBlibipq\fP(3).
diff --git a/iptables/iptables-extensions.8.in b/iptables/iptables-extensions.8.in
new file mode 100644
index 00000000..e02c81fb
--- /dev/null
+++ b/iptables/iptables-extensions.8.in
@@ -0,0 +1,27 @@
+.TH iptables-extensions 8 "" "@PACKAGE_AND_VERSION@" "@PACKAGE_AND_VERSION@"
+.SH NAME
+iptables-extensions \(em list of extensions in the standard iptables distribution
+.SH SYNOPSIS
+\fBip6tables\fP [\fB\-m\fP \fIname\fP [\fImodule-options\fP...]]
+[\fB\-j\fP \fItarget-name\fP [\fItarget-options\fP...]
+.PP
+\fBiptables\fP [\fB\-m\fP \fIname\fP [\fImodule-options\fP...]]
+[\fB\-j\fP \fItarget-name\fP [\fItarget-options\fP...]
+.SH MATCH EXTENSIONS
+iptables can use extended packet matching modules
+with the \fB\-m\fP or \fB\-\-match\fP
+options, followed by the matching module name; after these, various
+extra command line options become available, depending on the specific
+module.  You can specify multiple extended match modules in one line,
+and you can use the \fB\-h\fP or \fB\-\-help\fP
+options after the module has been specified to receive help specific
+to that module.
+.PP
+If the \fB\-p\fP or \fB\-\-protocol\fP was specified and if and only if an
+unknown option is encountered, iptables will try load a match module of the
+same name as the protocol, to try making the option available.
+.\" @MATCH@
+.SH TARGET EXTENSIONS
+iptables can use extended target modules: the following are included
+in the standard distribution.
+.\" @TARGET@
diff --git a/iptables/iptables.8.in b/iptables/iptables.8.in
index 59d6e040..48eb2fa1 100644
--- a/iptables/iptables.8.in
+++ b/iptables/iptables.8.in
@@ -355,25 +355,10 @@ corresponding to that rule's position in the chain.
 \fB\-\-modprobe=\fP\fIcommand\fP
 When adding or inserting rules into a chain, use \fIcommand\fP
 to load any necessary modules (targets, match extensions, etc).
-.SH MATCH EXTENSIONS
+.SH MATCH AND TARGET EXTENSIONS
 .PP
-iptables can use extended packet matching modules
-with the \fB\-m\fP or \fB\-\-match\fP
-options, followed by the matching module name; after these, various
-extra command line options become available, depending on the specific
-module.  You can specify multiple extended match modules in one line,
-and you can use the \fB\-h\fP or \fB\-\-help\fP
-options after the module has been specified to receive help specific
-to that module.
-.PP
-If the \fB\-p\fP or \fB\-\-protocol\fP was specified and if and only if an
-unknown option is encountered, iptables will try load a match module of the
-same name as the protocol, to try making the option available.
-.\" @MATCH@
-.SH TARGET EXTENSIONS
-iptables can use extended target modules: the following are included
-in the standard distribution.
-.\" @TARGET@
+iptables can use extended packet matching and target modules.
+A list of these is available in the \fBiptables\-extensions\fP(8) manpage.
 .SH DIAGNOSTICS
 Various error messages are printed to standard error.  The exit code
 is 0 for correct functioning.  Errors which appear to be caused by
@@ -410,6 +395,7 @@ There are several other changes in iptables.
 .SH SEE ALSO
 \fBiptables\-save\fP(8),
 \fBiptables\-restore\fP(8),
+\fBiptables\-extensions\fP(8),
 \fBip6tables\fP(8),
 \fBip6tables\-save\fP(8),
 \fBip6tables\-restore\fP(8),