From 543a4a41a615ce38ae32e887f94d3b85d50a93d9 Mon Sep 17 00:00:00 2001
From: Mattraks <16359027+Mattraks@users.noreply.github.com>
Date: Wed, 16 Dec 2020 02:36:08 +0800
Subject: [PATCH] Fix unable to start SFE with IPv4 only (#5914)

---
 package/lean/fast-classifier/Makefile              |  5 +++--
 package/lean/fast-classifier/src/fast-classifier.c |  6 ++++--
 package/lean/luci-app-sfe/luasrc/model/cbi/sfe.lua |  2 ++
 package/lean/shortcut-fe/Makefile                  | 10 ++++------
 4 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/package/lean/fast-classifier/Makefile b/package/lean/fast-classifier/Makefile
index 2b02f1b64..29d024e7b 100644
--- a/package/lean/fast-classifier/Makefile
+++ b/package/lean/fast-classifier/Makefile
@@ -3,6 +3,7 @@ include $(INCLUDE_DIR)/kernel.mk
 
 PKG_NAME:=fast-classifier
 PKG_RELEASE:=1
+PKG_CONFIG_DEPENDS := CONFIG_IPV6
 
 include $(INCLUDE_DIR)/package.mk
 
@@ -49,10 +50,10 @@ Example user space program that communicates with fast
 classifier kernel module
 endef
 
-SFE_MAKE_OPTS:=SFE_SUPPORT_IPV6=y
+SFE_MAKE_OPTS:=SFE_SUPPORT_IPV6=$(if $(CONFIG_IPV6),y,n)
 
 define Build/Compile/kmod
-	+$(MAKE) $(PKG_JOBS) -C "$(LINUX_DIR)" $(strip $(SFE_MAKE_OPTS)) \
+	+$(MAKE) $(PKG_JOBS) -C "$(LINUX_DIR)" $(SFE_MAKE_OPTS) \
 		$(KERNEL_MAKE_FLAGS) \
 		$(PKG_MAKE_FLAGS) \
 		M="$(PKG_BUILD_DIR)" \
diff --git a/package/lean/fast-classifier/src/fast-classifier.c b/package/lean/fast-classifier/src/fast-classifier.c
index 62255733e..160d14091 100644
--- a/package/lean/fast-classifier/src/fast-classifier.c
+++ b/package/lean/fast-classifier/src/fast-classifier.c
@@ -345,7 +345,9 @@ static bool fast_classifier_find_dev_and_mac_addr(struct sk_buff *skb, sfe_ip_ad
 		}
 
 		dst = (struct dst_entry *)rt;
-	} else {
+	}
+#ifdef SFE_SUPPORT_IPV6
+	else {
 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4, 17, 0))
 		rt6 = rt6_lookup(&init_net, (struct in6_addr *)addr->ip6, 0, 0, NULL, 0);
 #else
@@ -357,6 +359,7 @@ static bool fast_classifier_find_dev_and_mac_addr(struct sk_buff *skb, sfe_ip_ad
 
 		dst = (struct dst_entry *)rt6;
 	}
+#endif
 
 skip_dst_lookup:
 	rcu_read_lock();
@@ -1971,4 +1974,3 @@ module_exit(fast_classifier_exit)
 
 MODULE_DESCRIPTION("Shortcut Forwarding Engine - Connection Manager");
 MODULE_LICENSE("Dual BSD/GPL");
-
diff --git a/package/lean/luci-app-sfe/luasrc/model/cbi/sfe.lua b/package/lean/luci-app-sfe/luasrc/model/cbi/sfe.lua
index bb4c47616..c30f3aa17 100644
--- a/package/lean/luci-app-sfe/luasrc/model/cbi/sfe.lua
+++ b/package/lean/luci-app-sfe/luasrc/model/cbi/sfe.lua
@@ -21,11 +21,13 @@ wifi.rmempty = false
 wifi.description = translate("Enable Bridge Acceleration (may be functional conflict with bridge-mode VPN Server)")
 wifi:depends("enabled", 1)
 
+if nixio.fs.access("/proc/sys/net/ipv6") then
 ipv6 = s:option(Flag, "ipv6", translate("IPv6 Acceleration"))
 ipv6.default = 0
 ipv6.rmempty = false
 ipv6.description = translate("Enable IPv6 Acceleration")
 ipv6:depends("enabled", 1)
+end
 
 bbr = s:option(Flag, "bbr", translate("Enable BBR"))
 bbr.default = 0
diff --git a/package/lean/shortcut-fe/Makefile b/package/lean/shortcut-fe/Makefile
index 4061a7537..148cfda12 100644
--- a/package/lean/shortcut-fe/Makefile
+++ b/package/lean/shortcut-fe/Makefile
@@ -16,6 +16,7 @@ include $(INCLUDE_DIR)/kernel.mk
 
 PKG_NAME:=shortcut-fe
 PKG_RELEASE:=2
+PKG_CONFIG_DEPENDS := CONFIG_IPV6
 
 include $(INCLUDE_DIR)/package.mk
 
@@ -25,7 +26,7 @@ define KernelPackage/shortcut-fe
   SUBMENU:=Network Support
   DEPENDS:=
   TITLE:=Kernel driver for SFE
-  FILES:=$(PKG_BUILD_DIR)/shortcut-fe.ko $(PKG_BUILD_DIR)/shortcut-fe-ipv6.ko
+  FILES:=$(PKG_BUILD_DIR)/shortcut-fe.ko $(if $(CONFIG_IPV6),$(PKG_BUILD_DIR)/shortcut-fe-ipv6.ko,)
   KCONFIG:=CONFIG_NF_CONNTRACK_EVENTS=y \
 	   CONFIG_NF_CONNTRACK_TIMEOUT=y \
 	   CONFIG_SHORTCUT_FE=y \
@@ -56,16 +57,13 @@ define KernelPackage/shortcut-fe-cm/Description
 Simple connection manager for the Shortcut forwarding engine.
 endef
 
-EXTRA_CFLAGS+=-DSFE_SUPPORT_IPV6
-
 define Build/Compile
 	+$(MAKE) $(PKG_JOBS) -C "$(LINUX_DIR)" \
 		$(KERNEL_MAKE_FLAGS) \
 		$(PKG_MAKE_FLAGS) \
 		M="$(PKG_BUILD_DIR)" \
-		EXTRA_CFLAGS="$(EXTRA_CFLAGS)" \
-		SFE_SUPPORT_IPV6=1 \
-		modules
+		modules \
+		$(if $(CONFIG_IPV6),EXTRA_CFLAGS="-DSFE_SUPPORT_IPV6" SFE_SUPPORT_IPV6=y,)
 endef
 
 ifneq ($(CONFIG_PACKAGE_kmod-shortcut-fe)$(CONFIG_PACKAGE_kmod-shortcut-fe-cm),)