ANDROID: net: ipv6: autoconf routes into per-device tables
Currently, IPv6 router discovery always puts routes into
RT6_TABLE_MAIN. This causes problems for connection managers
that want to support multiple simultaneous network connections
and want control over which one is used by default (e.g., wifi
and wired).
To work around this connection managers typically take the routes
they prefer and copy them to static routes with low metrics in
the main table. This puts the burden on the connection manager
to watch netlink to see if the routes have changed, delete the
routes when their lifetime expires, etc.
Instead, this patch adds a per-interface sysctl to have the
kernel put autoconf routes into different tables. This allows
each interface to have its own autoconf table, and choosing the
default interface (or using different interfaces at the same
time for different types of traffic) can be done using
appropriate ip rules.
The sysctl behaves as follows:
- = 0: default. Put routes into RT6_TABLE_MAIN as before.
- > 0: manual. Put routes into the specified table.
- < 0: automatic. Add the absolute value of the sysctl to the
device's ifindex, and use that table.
The automatic mode is most useful in conjunction with
net.ipv6.conf.default.accept_ra_rt_table. A connection manager
or distribution could set it to, say, -100 on boot, and
thereafter just use IP rules.
Change-Id: I82d16e3737d9cdfa6489e649e247894d0d60cbb1
Signed-off-by: Lorenzo Colitti <lorenzo@google.com>
[AmitP: Refactored original changes to align with
the changes introduced by upstream commit
830218c1add1 ("net: ipv6: Fix processing of RAs in presence of VRF")]
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 1b57e11..0b0cdb16b 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2335,7 +2335,7 @@
const struct in6_addr *gwaddr,
struct net_device *dev)
{
- u32 tb_id = l3mdev_fib_table(dev) ? : RT6_TABLE_INFO;
+ u32 tb_id = l3mdev_fib_table(dev) ? : addrconf_rt_table(dev, RT6_TABLE_INFO);
int ifindex = dev->ifindex;
struct fib6_node *fn;
struct rt6_info *rt = NULL;
@@ -2351,7 +2351,7 @@
goto out;
for (rt = fn->leaf; rt; rt = rt->dst.rt6_next) {
- if (rt->dst.dev->ifindex != ifindex)
+ if (rt->dst.dev->ifindex != dev->ifindex)
continue;
if ((rt->rt6i_flags & (RTF_ROUTEINFO|RTF_GATEWAY)) != (RTF_ROUTEINFO|RTF_GATEWAY))
continue;
@@ -2382,7 +2382,7 @@
.fc_nlinfo.nl_net = net,
};
- cfg.fc_table = l3mdev_fib_table(dev) ? : RT6_TABLE_INFO,
+ cfg.fc_table = l3mdev_fib_table(dev) ? : addrconf_rt_table(dev, RT6_TABLE_INFO),
cfg.fc_dst = *prefix;
cfg.fc_gateway = *gwaddr;
@@ -2398,7 +2398,7 @@
struct rt6_info *rt6_get_dflt_router(const struct in6_addr *addr, struct net_device *dev)
{
- u32 tb_id = l3mdev_fib_table(dev) ? : RT6_TABLE_DFLT;
+ u32 tb_id = l3mdev_fib_table(dev) ? : addrconf_rt_table(dev, RT6_TABLE_MAIN);
struct rt6_info *rt;
struct fib6_table *table;
@@ -2424,7 +2424,7 @@
unsigned int pref)
{
struct fib6_config cfg = {
- .fc_table = l3mdev_fib_table(dev) ? : RT6_TABLE_DFLT,
+ .fc_table = l3mdev_fib_table(dev) ? : addrconf_rt_table(dev, RT6_TABLE_DFLT),
.fc_metric = IP6_RT_PRIO_USER,
.fc_ifindex = dev->ifindex,
.fc_flags = RTF_GATEWAY | RTF_ADDRCONF | RTF_DEFAULT |
@@ -2447,43 +2447,16 @@
return rt6_get_dflt_router(gwaddr, dev);
}
-static void __rt6_purge_dflt_routers(struct fib6_table *table)
-{
- struct rt6_info *rt;
-
-restart:
- read_lock_bh(&table->tb6_lock);
- for (rt = table->tb6_root.leaf; rt; rt = rt->dst.rt6_next) {
- if (rt->rt6i_flags & (RTF_DEFAULT | RTF_ADDRCONF) &&
- (!rt->rt6i_idev || rt->rt6i_idev->cnf.accept_ra != 2)) {
- dst_hold(&rt->dst);
- read_unlock_bh(&table->tb6_lock);
- ip6_del_rt(rt);
- goto restart;
- }
- }
- read_unlock_bh(&table->tb6_lock);
-
- table->flags &= ~RT6_TABLE_HAS_DFLT_ROUTER;
+int rt6_addrconf_purge(struct rt6_info *rt, void *arg) {
+ if (rt->rt6i_flags & (RTF_DEFAULT | RTF_ADDRCONF) &&
+ (!rt->rt6i_idev || rt->rt6i_idev->cnf.accept_ra != 2))
+ return -1;
+ return 0;
}
void rt6_purge_dflt_routers(struct net *net)
{
- struct fib6_table *table;
- struct hlist_head *head;
- unsigned int h;
-
- rcu_read_lock();
-
- for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
- head = &net->ipv6.fib_table_hash[h];
- hlist_for_each_entry_rcu(table, head, tb6_hlist) {
- if (table->flags & RT6_TABLE_HAS_DFLT_ROUTER)
- __rt6_purge_dflt_routers(table);
- }
- }
-
- rcu_read_unlock();
+ fib6_clean_all(net, rt6_addrconf_purge, NULL);
}
static void rtmsg_to_fib6_config(struct net *net,