net: track link-status of ipv4 nexthops
Add a fib flag called RTNH_F_LINKDOWN to any ipv4 nexthops that are
reachable via an interface where carrier is off. No action is taken,
but additional flags are passed to userspace to indicate carrier status.
This also includes a cleanup to fib_disable_ip to more clearly indicate
what event made the function call to replace the more cryptic force
option previously used.
v2: Split out kernel functionality into 2 patches, this patch simply
sets and clears new nexthop flag RTNH_F_LINKDOWN.
v3: Cleanups suggested by Alex as well as a bug noticed in
fib_sync_down_dev and fib_sync_up when multipath was not enabled.
v5: Whitespace and variable declaration fixups suggested by Dave.
v6: Style fixups noticed by Dave; ran checkpatch to be sure I got them
all.
Signed-off-by: Andy Gospodarek <gospo@cumulusnetworks.com>
Signed-off-by: Dinesh Dutt <ddutt@cumulusnetworks.com>
Acked-by: Scott Feldman <sfeldma@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index 54271ed..f73d27c 100644
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -305,9 +305,9 @@
/* Exported by fib_semantics.c */
int ip_fib_check_default(__be32 gw, struct net_device *dev);
-int fib_sync_down_dev(struct net_device *dev, int force);
+int fib_sync_down_dev(struct net_device *dev, unsigned long event);
int fib_sync_down_addr(struct net *net, __be32 local);
-int fib_sync_up(struct net_device *dev);
+int fib_sync_up(struct net_device *dev, unsigned int nh_flags);
void fib_select_multipath(struct fib_result *res);
/* Exported by fib_trie.c */
diff --git a/include/uapi/linux/rtnetlink.h b/include/uapi/linux/rtnetlink.h
index 17fb02f..fdd8f07 100644
--- a/include/uapi/linux/rtnetlink.h
+++ b/include/uapi/linux/rtnetlink.h
@@ -338,6 +338,9 @@
#define RTNH_F_PERVASIVE 2 /* Do recursive gateway lookup */
#define RTNH_F_ONLINK 4 /* Gateway is forced on link */
#define RTNH_F_OFFLOAD 8 /* offloaded route */
+#define RTNH_F_LINKDOWN 16 /* carrier-down on nexthop */
+
+#define RTNH_COMPARE_MASK (RTNH_F_DEAD | RTNH_F_LINKDOWN)
/* Macros to handle hexthops */
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 872494e..534eb14 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -1063,9 +1063,9 @@
net->ipv4.fibnl = NULL;
}
-static void fib_disable_ip(struct net_device *dev, int force)
+static void fib_disable_ip(struct net_device *dev, unsigned long event)
{
- if (fib_sync_down_dev(dev, force))
+ if (fib_sync_down_dev(dev, event))
fib_flush(dev_net(dev));
rt_cache_flush(dev_net(dev));
arp_ifdown(dev);
@@ -1081,7 +1081,7 @@
case NETDEV_UP:
fib_add_ifaddr(ifa);
#ifdef CONFIG_IP_ROUTE_MULTIPATH
- fib_sync_up(dev);
+ fib_sync_up(dev, RTNH_F_DEAD);
#endif
atomic_inc(&net->ipv4.dev_addr_genid);
rt_cache_flush(dev_net(dev));
@@ -1093,7 +1093,7 @@
/* Last address was deleted from this interface.
* Disable IP.
*/
- fib_disable_ip(dev, 1);
+ fib_disable_ip(dev, event);
} else {
rt_cache_flush(dev_net(dev));
}
@@ -1107,9 +1107,10 @@
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
struct in_device *in_dev;
struct net *net = dev_net(dev);
+ unsigned int flags;
if (event == NETDEV_UNREGISTER) {
- fib_disable_ip(dev, 2);
+ fib_disable_ip(dev, event);
rt_flush_dev(dev);
return NOTIFY_DONE;
}
@@ -1124,16 +1125,22 @@
fib_add_ifaddr(ifa);
} endfor_ifa(in_dev);
#ifdef CONFIG_IP_ROUTE_MULTIPATH
- fib_sync_up(dev);
+ fib_sync_up(dev, RTNH_F_DEAD);
#endif
atomic_inc(&net->ipv4.dev_addr_genid);
rt_cache_flush(net);
break;
case NETDEV_DOWN:
- fib_disable_ip(dev, 0);
+ fib_disable_ip(dev, event);
break;
- case NETDEV_CHANGEMTU:
case NETDEV_CHANGE:
+ flags = dev_get_flags(dev);
+ if (flags & (IFF_RUNNING | IFF_LOWER_UP))
+ fib_sync_up(dev, RTNH_F_LINKDOWN);
+ else
+ fib_sync_down_dev(dev, event);
+ /* fall through */
+ case NETDEV_CHANGEMTU:
rt_cache_flush(net);
break;
}
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 28ec3c1..b1b305b 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -266,7 +266,7 @@
#ifdef CONFIG_IP_ROUTE_CLASSID
nh->nh_tclassid != onh->nh_tclassid ||
#endif
- ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_F_DEAD))
+ ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_COMPARE_MASK))
return -1;
onh++;
} endfor_nexthops(fi);
@@ -318,7 +318,7 @@
nfi->fib_type == fi->fib_type &&
memcmp(nfi->fib_metrics, fi->fib_metrics,
sizeof(u32) * RTAX_MAX) == 0 &&
- ((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_F_DEAD) == 0 &&
+ !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
(nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
return fi;
}
@@ -604,6 +604,8 @@
return -ENODEV;
if (!(dev->flags & IFF_UP))
return -ENETDOWN;
+ if (!netif_carrier_ok(dev))
+ nh->nh_flags |= RTNH_F_LINKDOWN;
nh->nh_dev = dev;
dev_hold(dev);
nh->nh_scope = RT_SCOPE_LINK;
@@ -636,6 +638,8 @@
if (!dev)
goto out;
dev_hold(dev);
+ if (!netif_carrier_ok(dev))
+ nh->nh_flags |= RTNH_F_LINKDOWN;
err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
} else {
struct in_device *in_dev;
@@ -654,6 +658,8 @@
nh->nh_dev = in_dev->dev;
dev_hold(nh->nh_dev);
nh->nh_scope = RT_SCOPE_HOST;
+ if (!netif_carrier_ok(nh->nh_dev))
+ nh->nh_flags |= RTNH_F_LINKDOWN;
err = 0;
}
out:
@@ -920,11 +926,17 @@
if (!nh->nh_dev)
goto failure;
} else {
+ int linkdown = 0;
+
change_nexthops(fi) {
err = fib_check_nh(cfg, fi, nexthop_nh);
if (err != 0)
goto failure;
+ if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN)
+ linkdown++;
} endfor_nexthops(fi)
+ if (linkdown == fi->fib_nhs)
+ fi->fib_flags |= RTNH_F_LINKDOWN;
}
if (fi->fib_prefsrc) {
@@ -1103,7 +1115,7 @@
return ret;
}
-int fib_sync_down_dev(struct net_device *dev, int force)
+int fib_sync_down_dev(struct net_device *dev, unsigned long event)
{
int ret = 0;
int scope = RT_SCOPE_NOWHERE;
@@ -1112,7 +1124,8 @@
struct hlist_head *head = &fib_info_devhash[hash];
struct fib_nh *nh;
- if (force)
+ if (event == NETDEV_UNREGISTER ||
+ event == NETDEV_DOWN)
scope = -1;
hlist_for_each_entry(nh, head, nh_hash) {
@@ -1129,7 +1142,15 @@
dead++;
else if (nexthop_nh->nh_dev == dev &&
nexthop_nh->nh_scope != scope) {
- nexthop_nh->nh_flags |= RTNH_F_DEAD;
+ switch (event) {
+ case NETDEV_DOWN:
+ case NETDEV_UNREGISTER:
+ nexthop_nh->nh_flags |= RTNH_F_DEAD;
+ /* fall through */
+ case NETDEV_CHANGE:
+ nexthop_nh->nh_flags |= RTNH_F_LINKDOWN;
+ break;
+ }
#ifdef CONFIG_IP_ROUTE_MULTIPATH
spin_lock_bh(&fib_multipath_lock);
fi->fib_power -= nexthop_nh->nh_power;
@@ -1139,14 +1160,23 @@
dead++;
}
#ifdef CONFIG_IP_ROUTE_MULTIPATH
- if (force > 1 && nexthop_nh->nh_dev == dev) {
+ if (event == NETDEV_UNREGISTER &&
+ nexthop_nh->nh_dev == dev) {
dead = fi->fib_nhs;
break;
}
#endif
} endfor_nexthops(fi)
if (dead == fi->fib_nhs) {
- fi->fib_flags |= RTNH_F_DEAD;
+ switch (event) {
+ case NETDEV_DOWN:
+ case NETDEV_UNREGISTER:
+ fi->fib_flags |= RTNH_F_DEAD;
+ /* fall through */
+ case NETDEV_CHANGE:
+ fi->fib_flags |= RTNH_F_LINKDOWN;
+ break;
+ }
ret++;
}
}
@@ -1210,13 +1240,11 @@
return;
}
-#ifdef CONFIG_IP_ROUTE_MULTIPATH
-
/*
* Dead device goes up. We wake up dead nexthops.
* It takes sense only on multipath routes.
*/
-int fib_sync_up(struct net_device *dev)
+int fib_sync_up(struct net_device *dev, unsigned int nh_flags)
{
struct fib_info *prev_fi;
unsigned int hash;
@@ -1243,7 +1271,7 @@
prev_fi = fi;
alive = 0;
change_nexthops(fi) {
- if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
+ if (!(nexthop_nh->nh_flags & nh_flags)) {
alive++;
continue;
}
@@ -1254,14 +1282,18 @@
!__in_dev_get_rtnl(dev))
continue;
alive++;
+#ifdef CONFIG_IP_ROUTE_MULTIPATH
spin_lock_bh(&fib_multipath_lock);
nexthop_nh->nh_power = 0;
- nexthop_nh->nh_flags &= ~RTNH_F_DEAD;
+ nexthop_nh->nh_flags &= ~nh_flags;
spin_unlock_bh(&fib_multipath_lock);
+#else
+ nexthop_nh->nh_flags &= ~nh_flags;
+#endif
} endfor_nexthops(fi)
if (alive > 0) {
- fi->fib_flags &= ~RTNH_F_DEAD;
+ fi->fib_flags &= ~nh_flags;
ret++;
}
}
@@ -1269,6 +1301,8 @@
return ret;
}
+#ifdef CONFIG_IP_ROUTE_MULTIPATH
+
/*
* The algorithm is suboptimal, but it provides really
* fair weighted route distribution.