[PATCH nf-next v6] netfilter: Make legacy configs user selectable

[Breno Leitao]

This option makes legacy Netfilter Kconfig user selectable, giving users
the option to configure iptables without enabling any other config.

Make the following KConfig entries user selectable:
 * BRIDGE_NF_EBTABLES_LEGACY
 * IP_NF_ARPTABLES
 * IP_NF_IPTABLES_LEGACY
 * IP6_NF_IPTABLES_LEGACY

Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>
---
Changelog:
v6:
 * Expand it for BRIDGE_NF_EBTABLES_LEGACY and IP_NF_ARPTABLES (Pablo)
 * Merge all changes in a single patch (Pablo)

v5:
 * Change the description of the legacy Kconfig (Pablo)
 * https://lore.kernel.org/all/20240909084620.3155679-2-leitao@xxxxxxxxxx/

v4:
 * Remove the "depends on" part, which may come later in a separate
   change, given its intrusive on how to configure selftests
 * https://lore.kernel.org/all/20240829161656.832208-1-leitao@xxxxxxxxxx/

v3:
 * Make sure that the generate from  tools/testing/selftests/net/config
   look the same before and after. (Jakub)
 * https://lore.kernel.org/all/20240827145242.3094777-1-leitao@xxxxxxxxxx/

v2:
 * Added the new configuration in the selftest configs (Jakub)
 * Added this simple cover letter
 * https://lore.kernel.org/all/20240823174855.3052334-1-leitao@xxxxxxxxxx/

v1:
 * https://lore.kernel.org/all/20240822175537.3626036-1-leitao@xxxxxxxxxx/


 net/bridge/netfilter/Kconfig |  8 +++++++-
 net/ipv4/netfilter/Kconfig   | 16 ++++++++++++++--
 net/ipv6/netfilter/Kconfig   |  9 ++++++++-
 3 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/net/bridge/netfilter/Kconfig b/net/bridge/netfilter/Kconfig
index 104c0125e32e..f16bbbbb9481 100644
--- a/net/bridge/netfilter/Kconfig
+++ b/net/bridge/netfilter/Kconfig
@@ -41,7 +41,13 @@ config NF_CONNTRACK_BRIDGE
 
 # old sockopt interface and eval loop
 config BRIDGE_NF_EBTABLES_LEGACY
-	tristate
+	tristate "Legacy EBTABLES support"
+	depends on BRIDGE && NETFILTER_XTABLES
+	default n
+	help
+	 Legacy ebtables packet/frame classifier.
+	 This is not needed if you are using ebtables over nftables
+	 (iptables-nft).
 
 menuconfig BRIDGE_NF_EBTABLES
 	tristate "Ethernet Bridge tables (ebtables) support"
diff --git a/net/ipv4/netfilter/Kconfig b/net/ipv4/netfilter/Kconfig
index 1b991b889506..ef8009281da5 100644
--- a/net/ipv4/netfilter/Kconfig
+++ b/net/ipv4/netfilter/Kconfig
@@ -12,7 +12,13 @@ config NF_DEFRAG_IPV4
 
 # old sockopt interface and eval loop
 config IP_NF_IPTABLES_LEGACY
-	tristate
+	tristate "Legacy IP tables support"
+	default	n
+	select NETFILTER_XTABLES
+	help
+	  iptables is a legacy packet classifier.
+	  This is not needed if you are using iptables over nftables
+	  (iptables-nft).
 
 config NF_SOCKET_IPV4
 	tristate "IPv4 socket lookup support"
@@ -318,7 +324,13 @@ endif # IP_NF_IPTABLES
 
 # ARP tables
 config IP_NF_ARPTABLES
-	tristate
+	tristate "Legacy ARPTABLES support"
+	depends on NETFILTER_XTABLES
+	default n
+	help
+	  arptables is a legacy packet classifier.
+	  This is not needed if you are using arptables over nftables
+	  (iptables-nft).
 
 config NFT_COMPAT_ARP
 	tristate
diff --git a/net/ipv6/netfilter/Kconfig b/net/ipv6/netfilter/Kconfig
index f3c8e2d918e1..e087a8e97ba7 100644
--- a/net/ipv6/netfilter/Kconfig
+++ b/net/ipv6/netfilter/Kconfig
@@ -8,7 +8,14 @@ menu "IPv6: Netfilter Configuration"
 
 # old sockopt interface and eval loop
 config IP6_NF_IPTABLES_LEGACY
-	tristate
+	tristate "Legacy IP6 tables support"
+	depends on INET && IPV6
+	select NETFILTER_XTABLES
+	default n
+	help
+	  ip6tables is a legacy packet classifier.
+	  This is not needed if you are using iptables over nftables
+	  (iptables-nft).
 
 config NF_SOCKET_IPV6
 	tristate "IPv6 socket lookup support"
-- 
2.43.5