net: ipv6: put host and anycast routes on device with address

One nagging difference between ipv4 and ipv6 is host routes for ipv6
addresses are installed using the loopback device or VRF / L3 Master
device. e.g.,

    2001:db8:1::/120 dev veth0 proto kernel metric 256 pref medium
    local 2001:db8:1::1 dev lo table local proto kernel metric 0 pref medium

Using the loopback device is convenient -- necessary for local tx, but
has some nasty side effects, most notably setting the 'lo' device down
causes all host routes for all local IPv6 address to be removed from the
FIB and completely breaks IPv6 networking across all interfaces.

This patch puts FIB entries for IPv6 routes against the device. This
simplifies the routes in the FIB, for example by making dst->dev and
rt6i_idev->dev the same (a future patch can look at removing the device
reference taken for rt6i_idev for FIB entries).

When copies are made on FIB lookups, the cloned route has dst->dev
set to loopback (or the L3 master device). This is needed for the
local Tx of packets to local addresses.

With fib entries allocated against the real network device, the addrconf
code that reinserts host routes on admin up of 'lo' is no longer needed.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 0 insertions, 42 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 640792e1ecb7..45d0a24644de 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -3030,9 +3030,6 @@ static void sit_add_v4_addrs(struct inet6_dev *idev)
 static void init_loopback(struct net_device *dev)
 {
 	struct inet6_dev  *idev;
-	struct net_device *sp_dev;
-	struct inet6_ifaddr *sp_ifa;
-	struct rt6_info *sp_rt;
 
 	/* ::1 */
 
@@ -3045,45 +3042,6 @@ static void init_loopback(struct net_device *dev)
 	}
 
 	add_addr(idev, &in6addr_loopback, 128, IFA_HOST);
-
-	/* Add routes to other interface's IPv6 addresses */
-	for_each_netdev(dev_net(dev), sp_dev) {
-		if (!strcmp(sp_dev->name, dev->name))
-			continue;
-
-		idev = __in6_dev_get(sp_dev);
-		if (!idev)
-			continue;
-
-		read_lock_bh(&idev->lock);
-		list_for_each_entry(sp_ifa, &idev->addr_list, if_list) {
-
-			if (sp_ifa->flags & (IFA_F_DADFAILED | IFA_F_TENTATIVE))
-				continue;
-
-			if (sp_ifa->rt) {
-				/* This dst has been added to garbage list when
-				 * lo device down, release this obsolete dst and
-				 * reallocate a new router for ifa.
-				 */
-				if (!sp_ifa->rt->rt6i_node) {
-					ip6_rt_put(sp_ifa->rt);
-					sp_ifa->rt = NULL;
-				} else {
-					continue;
-				}
-			}
-
-			sp_rt = addrconf_dst_alloc(idev, &sp_ifa->addr, false);
-
-			/* Failure cases are ignored */
-			if (!IS_ERR(sp_rt)) {
-				sp_ifa->rt = sp_rt;
-				ip6_ins_rt(sp_rt);
-			}
-		}
-		read_unlock_bh(&idev->lock);
-	}
 }
 
 void addrconf_add_linklocal(struct inet6_dev *idev,