[PATCH] generic: Remove IPv6 depependency of bridge in 2.6.38+

Since 2.6.38 the bridge module has a dependency to IPv6 if IPv6 is
enabled. Since the IPv6 module isn't exactly lightweight and bridge also
only needs a single function from IPv6, it's rather easy to create a
common "lib" module with a RCU pointer to the actual implementation, if
the IPv6 module is loaded (although slightly hackish).

The codepath seems to be only taken when using IPv6, so there should be
no negative side effects when IPv6 isn't loaded. I did not measure how
big the performance impact is.

Signed-off-by: Jonas Gorski <jonas.gorski+openwrt@gmail.com>
SVN-Revision: 27237

diff --git a/target/linux/generic/patches-2.6.38/643-bridge_remove_ipv6_dependency.patch b/target/linux/generic/patches-2.6.38/643-bridge_remove_ipv6_dependency.patch
new file mode 100644 (file)
index 0000000..7f4f754
--- /dev/null
+++ b/target/linux/generic/patches-2.6.38/643-bridge_remove_ipv6_dependency.patch
@@ -0,0 +1,101 @@
+--- a/include/net/addrconf.h
++++ b/include/net/addrconf.h
+@@ -93,6 +93,12 @@ extern void                 addrconf_join_solict(struc
+ extern void                   addrconf_leave_solict(struct inet6_dev *idev,
+                                       struct in6_addr *addr);
+ 
++extern int                    (*ipv6_dev_get_saddr_hook)(struct net *net,
++                                              struct net_device *dev,
++                                              const struct in6_addr *daddr,
++                                              unsigned int srcprefs,
++                                              struct in6_addr *saddr);
++
+ static inline unsigned long addrconf_timeout_fixup(u32 timeout,
+                                                   unsigned unit)
+ {
+--- a/net/bridge/Kconfig
++++ b/net/bridge/Kconfig
+@@ -6,7 +6,6 @@ config BRIDGE
+       tristate "802.1d Ethernet Bridging"
+       select LLC
+       select STP
+-      depends on IPV6 || IPV6=n
+       ---help---
+         If you say Y here, then your Linux box will be able to act as an
+         Ethernet bridge, which means that the different Ethernet segments it
+--- a/net/ipv6/Makefile
++++ b/net/ipv6/Makefile
+@@ -40,3 +40,4 @@ obj-$(CONFIG_IPV6_TUNNEL) += ip6_tunnel.
+ obj-y += addrconf_core.o exthdrs_core.o
+ 
+ obj-$(subst m,y,$(CONFIG_IPV6)) += inet6_hashtables.o
++obj-$(subst m,y,$(CONFIG_IPV6)) += inet6_stubs.o
+--- a/net/ipv6/addrconf.c
++++ b/net/ipv6/addrconf.c
+@@ -1119,7 +1119,7 @@ out:
+       return ret;
+ }
+ 
+-int ipv6_dev_get_saddr(struct net *net, struct net_device *dst_dev,
++static int __ipv6_dev_get_saddr(struct net *net, struct net_device *dst_dev,
+                      const struct in6_addr *daddr, unsigned int prefs,
+                      struct in6_addr *saddr)
+ {
+@@ -1244,7 +1244,6 @@ try_nextdev:
+       in6_ifa_put(hiscore->ifa);
+       return 0;
+ }
+-EXPORT_SYMBOL(ipv6_dev_get_saddr);
+ 
+ int ipv6_get_lladdr(struct net_device *dev, struct in6_addr *addr,
+                   unsigned char banned_flags)
+@@ -4718,6 +4717,9 @@ int __init addrconf_init(void)
+ 
+       ipv6_addr_label_rtnl_register();
+ 
++      BUG_ON(ipv6_dev_get_saddr_hook != NULL);
++      rcu_assign_pointer(ipv6_dev_get_saddr_hook, __ipv6_dev_get_saddr);
++
+       return 0;
+ errout:
+       rtnl_af_unregister(&inet6_ops);
+@@ -4736,6 +4738,9 @@ void addrconf_cleanup(void)
+       struct net_device *dev;
+       int i;
+ 
++      rcu_assign_pointer(ipv6_dev_get_saddr_hook, NULL);
++      synchronize_rcu();
++
+       unregister_netdevice_notifier(&ipv6_dev_notf);
+       unregister_pernet_subsys(&addrconf_ops);
+       ipv6_addr_label_cleanup();
+--- /dev/null
++++ b/net/ipv6/inet6_stubs.c
+@@ -0,0 +1,27 @@
++/*
++ *      This program is free software; you can redistribute it and/or
++ *      modify it under the terms of the GNU General Public License
++ *      as published by the Free Software Foundation; either version
++ *      2 of the License, or (at your option) any later version.
++ */
++#include <net/ipv6.h>
++
++int (*ipv6_dev_get_saddr_hook)(struct net *net, struct net_device *dev,
++                      const struct in6_addr *daddr, unsigned int srcprefs,
++                      struct in6_addr *saddr);
++
++EXPORT_SYMBOL(ipv6_dev_get_saddr_hook);
++
++int ipv6_dev_get_saddr(struct net *net, struct net_device *dst_dev,
++                      const struct in6_addr *daddr, unsigned int prefs,
++                      struct in6_addr *saddr)
++{
++      typeof(ipv6_dev_get_saddr_hook) dev_get_saddr = rcu_dereference(ipv6_dev_get_saddr_hook);
++
++      if (dev_get_saddr)
++              return dev_get_saddr(net, dst_dev, daddr, prefs, saddr);
++
++      return -EADDRNOTAVAIL;
++}
++EXPORT_SYMBOL(ipv6_dev_get_saddr);
++

diff --git a/target/linux/generic/patches-2.6.39/643-bridge_remove_ipv6_dependency.patch b/target/linux/generic/patches-2.6.39/643-bridge_remove_ipv6_dependency.patch
new file mode 100644 (file)
index 0000000..679561e
--- /dev/null
+++ b/target/linux/generic/patches-2.6.39/643-bridge_remove_ipv6_dependency.patch
@@ -0,0 +1,101 @@
+--- a/include/net/addrconf.h
++++ b/include/net/addrconf.h
+@@ -93,6 +93,12 @@ extern void                 addrconf_join_solict(struc
+ extern void                   addrconf_leave_solict(struct inet6_dev *idev,
+                                       struct in6_addr *addr);
+ 
++extern int                    (*ipv6_dev_get_saddr_hook)(struct net *net,
++                                              struct net_device *dev,
++                                              const struct in6_addr *daddr,
++                                              unsigned int srcprefs,
++                                              struct in6_addr *saddr);
++
+ static inline unsigned long addrconf_timeout_fixup(u32 timeout,
+                                                   unsigned unit)
+ {
+--- a/net/bridge/Kconfig
++++ b/net/bridge/Kconfig
+@@ -6,7 +6,6 @@ config BRIDGE
+       tristate "802.1d Ethernet Bridging"
+       select LLC
+       select STP
+-      depends on IPV6 || IPV6=n
+       ---help---
+         If you say Y here, then your Linux box will be able to act as an
+         Ethernet bridge, which means that the different Ethernet segments it
+--- a/net/ipv6/Makefile
++++ b/net/ipv6/Makefile
+@@ -40,3 +40,4 @@ obj-$(CONFIG_IPV6_TUNNEL) += ip6_tunnel.
+ obj-y += addrconf_core.o exthdrs_core.o
+ 
+ obj-$(subst m,y,$(CONFIG_IPV6)) += inet6_hashtables.o
++obj-$(subst m,y,$(CONFIG_IPV6)) += inet6_stubs.o
+--- a/net/ipv6/addrconf.c
++++ b/net/ipv6/addrconf.c
+@@ -1116,7 +1116,7 @@ out:
+       return ret;
+ }
+ 
+-int ipv6_dev_get_saddr(struct net *net, struct net_device *dst_dev,
++static int __ipv6_dev_get_saddr(struct net *net, struct net_device *dst_dev,
+                      const struct in6_addr *daddr, unsigned int prefs,
+                      struct in6_addr *saddr)
+ {
+@@ -1241,7 +1241,6 @@ try_nextdev:
+       in6_ifa_put(hiscore->ifa);
+       return 0;
+ }
+-EXPORT_SYMBOL(ipv6_dev_get_saddr);
+ 
+ int ipv6_get_lladdr(struct net_device *dev, struct in6_addr *addr,
+                   unsigned char banned_flags)
+@@ -4715,6 +4714,9 @@ int __init addrconf_init(void)
+ 
+       ipv6_addr_label_rtnl_register();
+ 
++      BUG_ON(ipv6_dev_get_saddr_hook != NULL);
++      rcu_assign_pointer(ipv6_dev_get_saddr_hook, __ipv6_dev_get_saddr);
++
+       return 0;
+ errout:
+       rtnl_af_unregister(&inet6_ops);
+@@ -4733,6 +4735,9 @@ void addrconf_cleanup(void)
+       struct net_device *dev;
+       int i;
+ 
++      rcu_assign_pointer(ipv6_dev_get_saddr_hook, NULL);
++      synchronize_rcu();
++
+       unregister_netdevice_notifier(&ipv6_dev_notf);
+       unregister_pernet_subsys(&addrconf_ops);
+       ipv6_addr_label_cleanup();
+--- /dev/null
++++ b/net/ipv6/inet6_stubs.c
+@@ -0,0 +1,27 @@
++/*
++ *      This program is free software; you can redistribute it and/or
++ *      modify it under the terms of the GNU General Public License
++ *      as published by the Free Software Foundation; either version
++ *      2 of the License, or (at your option) any later version.
++ */
++#include <net/ipv6.h>
++
++int (*ipv6_dev_get_saddr_hook)(struct net *net, struct net_device *dev,
++                      const struct in6_addr *daddr, unsigned int srcprefs,
++                      struct in6_addr *saddr);
++
++EXPORT_SYMBOL(ipv6_dev_get_saddr_hook);
++
++int ipv6_dev_get_saddr(struct net *net, struct net_device *dst_dev,
++                      const struct in6_addr *daddr, unsigned int prefs,
++                      struct in6_addr *saddr)
++{
++      typeof(ipv6_dev_get_saddr_hook) dev_get_saddr = rcu_dereference(ipv6_dev_get_saddr_hook);
++
++      if (dev_get_saddr)
++              return dev_get_saddr(net, dst_dev, daddr, prefs, saddr);
++
++      return -EADDRNOTAVAIL;
++}
++EXPORT_SYMBOL(ipv6_dev_get_saddr);
++

diff --git a/target/linux/generic/patches-3.0/643-bridge_remove_ipv6_dependency.patch b/target/linux/generic/patches-3.0/643-bridge_remove_ipv6_dependency.patch
new file mode 100644 (file)
index 0000000..5eac489
--- /dev/null
+++ b/target/linux/generic/patches-3.0/643-bridge_remove_ipv6_dependency.patch
@@ -0,0 +1,101 @@
+--- a/include/net/addrconf.h
++++ b/include/net/addrconf.h
+@@ -91,6 +91,12 @@ extern void                 addrconf_join_solict(struc
+ extern void                   addrconf_leave_solict(struct inet6_dev *idev,
+                                       const struct in6_addr *addr);
+ 
++extern int                    (*ipv6_dev_get_saddr_hook)(struct net *net,
++                                              struct net_device *dev,
++                                              const struct in6_addr *daddr,
++                                              unsigned int srcprefs,
++                                              struct in6_addr *saddr);
++
+ static inline unsigned long addrconf_timeout_fixup(u32 timeout,
+                                                   unsigned unit)
+ {
+--- a/net/bridge/Kconfig
++++ b/net/bridge/Kconfig
+@@ -6,7 +6,6 @@ config BRIDGE
+       tristate "802.1d Ethernet Bridging"
+       select LLC
+       select STP
+-      depends on IPV6 || IPV6=n
+       ---help---
+         If you say Y here, then your Linux box will be able to act as an
+         Ethernet bridge, which means that the different Ethernet segments it
+--- a/net/ipv6/Makefile
++++ b/net/ipv6/Makefile
+@@ -40,3 +40,4 @@ obj-$(CONFIG_IPV6_TUNNEL) += ip6_tunnel.
+ obj-y += addrconf_core.o exthdrs_core.o
+ 
+ obj-$(subst m,y,$(CONFIG_IPV6)) += inet6_hashtables.o
++obj-$(subst m,y,$(CONFIG_IPV6)) += inet6_stubs.o
+--- a/net/ipv6/addrconf.c
++++ b/net/ipv6/addrconf.c
+@@ -1106,7 +1106,7 @@ out:
+       return ret;
+ }
+ 
+-int ipv6_dev_get_saddr(struct net *net, struct net_device *dst_dev,
++static int __ipv6_dev_get_saddr(struct net *net, struct net_device *dst_dev,
+                      const struct in6_addr *daddr, unsigned int prefs,
+                      struct in6_addr *saddr)
+ {
+@@ -1231,7 +1231,6 @@ try_nextdev:
+       in6_ifa_put(hiscore->ifa);
+       return 0;
+ }
+-EXPORT_SYMBOL(ipv6_dev_get_saddr);
+ 
+ int ipv6_get_lladdr(struct net_device *dev, struct in6_addr *addr,
+                   unsigned char banned_flags)
+@@ -4705,6 +4704,9 @@ int __init addrconf_init(void)
+ 
+       ipv6_addr_label_rtnl_register();
+ 
++      BUG_ON(ipv6_dev_get_saddr_hook != NULL);
++      rcu_assign_pointer(ipv6_dev_get_saddr_hook, __ipv6_dev_get_saddr);
++
+       return 0;
+ errout:
+       rtnl_af_unregister(&inet6_ops);
+@@ -4723,6 +4725,9 @@ void addrconf_cleanup(void)
+       struct net_device *dev;
+       int i;
+ 
++      rcu_assign_pointer(ipv6_dev_get_saddr_hook, NULL);
++      synchronize_rcu();
++
+       unregister_netdevice_notifier(&ipv6_dev_notf);
+       unregister_pernet_subsys(&addrconf_ops);
+       ipv6_addr_label_cleanup();
+--- /dev/null
++++ b/net/ipv6/inet6_stubs.c
+@@ -0,0 +1,27 @@
++/*
++ *      This program is free software; you can redistribute it and/or
++ *      modify it under the terms of the GNU General Public License
++ *      as published by the Free Software Foundation; either version
++ *      2 of the License, or (at your option) any later version.
++ */
++#include <net/ipv6.h>
++
++int (*ipv6_dev_get_saddr_hook)(struct net *net, struct net_device *dev,
++                      const struct in6_addr *daddr, unsigned int srcprefs,
++                      struct in6_addr *saddr);
++
++EXPORT_SYMBOL(ipv6_dev_get_saddr_hook);
++
++int ipv6_dev_get_saddr(struct net *net, struct net_device *dst_dev,
++                      const struct in6_addr *daddr, unsigned int prefs,
++                      struct in6_addr *saddr)
++{
++      typeof(ipv6_dev_get_saddr_hook) dev_get_saddr = rcu_dereference(ipv6_dev_get_saddr_hook);
++
++      if (dev_get_saddr)
++              return dev_get_saddr(net, dst_dev, daddr, prefs, saddr);
++
++      return -EADDRNOTAVAIL;
++}
++EXPORT_SYMBOL(ipv6_dev_get_saddr);
++