[PATCH 5.4 054/123] net/ipv6: remove the old peer route if change it to a new one

From: Greg Kroah-Hartman
Date: Tue Mar 17 2020 - 07:03:19 EST


From: Hangbin Liu <liuhangbin@xxxxxxxxx>

[ Upstream commit d0098e4c6b83e502cc1cd96d67ca86bc79a6c559 ]

When we modify the peer route and changed it to a new one, we should
remove the old route first. Before the fix:

+ ip addr add dev dummy1 2001:db8::1 peer 2001:db8::2
+ ip -6 route show dev dummy1
2001:db8::1 proto kernel metric 256 pref medium
2001:db8::2 proto kernel metric 256 pref medium
+ ip addr change dev dummy1 2001:db8::1 peer 2001:db8::3
+ ip -6 route show dev dummy1
2001:db8::1 proto kernel metric 256 pref medium
2001:db8::2 proto kernel metric 256 pref medium

After the fix:
+ ip addr change dev dummy1 2001:db8::1 peer 2001:db8::3
+ ip -6 route show dev dummy1
2001:db8::1 proto kernel metric 256 pref medium
2001:db8::3 proto kernel metric 256 pref medium

This patch depend on the previous patch "net/ipv6: need update peer route
when modify metric" to update new peer route after delete old one.

Signed-off-by: Hangbin Liu <liuhangbin@xxxxxxxxx>
Reviewed-by: David Ahern <dsahern@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv6/addrconf.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)

--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1226,11 +1226,13 @@ check_cleanup_prefix_route(struct inet6_
}

static void
-cleanup_prefix_route(struct inet6_ifaddr *ifp, unsigned long expires, bool del_rt)
+cleanup_prefix_route(struct inet6_ifaddr *ifp, unsigned long expires,
+ bool del_rt, bool del_peer)
{
struct fib6_info *f6i;

- f6i = addrconf_get_prefix_route(&ifp->addr, ifp->prefix_len,
+ f6i = addrconf_get_prefix_route(del_peer ? &ifp->peer_addr : &ifp->addr,
+ ifp->prefix_len,
ifp->idev->dev, 0, RTF_DEFAULT, true);
if (f6i) {
if (del_rt)
@@ -1293,7 +1295,7 @@ static void ipv6_del_addr(struct inet6_i

if (action != CLEANUP_PREFIX_RT_NOP) {
cleanup_prefix_route(ifp, expires,
- action == CLEANUP_PREFIX_RT_DEL);
+ action == CLEANUP_PREFIX_RT_DEL, false);
}

/* clean up prefsrc entries */
@@ -4631,6 +4633,7 @@ static int inet6_addr_modify(struct inet
unsigned long timeout;
bool was_managetempaddr;
bool had_prefixroute;
+ bool new_peer = false;

ASSERT_RTNL();

@@ -4662,6 +4665,13 @@ static int inet6_addr_modify(struct inet
cfg->preferred_lft = timeout;
}

+ if (cfg->peer_pfx &&
+ memcmp(&ifp->peer_addr, cfg->peer_pfx, sizeof(struct in6_addr))) {
+ if (!ipv6_addr_any(&ifp->peer_addr))
+ cleanup_prefix_route(ifp, expires, true, true);
+ new_peer = true;
+ }
+
spin_lock_bh(&ifp->lock);
was_managetempaddr = ifp->flags & IFA_F_MANAGETEMPADDR;
had_prefixroute = ifp->flags & IFA_F_PERMANENT &&
@@ -4677,6 +4687,9 @@ static int inet6_addr_modify(struct inet
if (cfg->rt_priority && cfg->rt_priority != ifp->rt_priority)
ifp->rt_priority = cfg->rt_priority;

+ if (new_peer)
+ ifp->peer_addr = *cfg->peer_pfx;
+
spin_unlock_bh(&ifp->lock);
if (!(ifp->flags&IFA_F_TENTATIVE))
ipv6_ifa_notify(0, ifp);
@@ -4712,7 +4725,7 @@ static int inet6_addr_modify(struct inet

if (action != CLEANUP_PREFIX_RT_NOP) {
cleanup_prefix_route(ifp, rt_expires,
- action == CLEANUP_PREFIX_RT_DEL);
+ action == CLEANUP_PREFIX_RT_DEL, false);
}
}