Re: [patch net-next 12/15] ipv4: fib: Notify about nexthop status changes
From: Andy Gospodarek <andy@greyhouse.net>
Date: 2017-02-08 15:38:13
On Wed, Feb 8, 2017 at 5:16 AM, Jiri Pirko [off-list ref] wrote:
From: Ido Schimmel <redacted>
When a multipath route is hit the kernel doesn't consider nexthops that
are DEAD or LINKDOWN when IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN is set.
Devices that offload multipath routes need to be made aware of nexthop
status changes. Otherwise, the device will keep forwarding packets to
non-functional nexthops.
Add the FIB_EVENT_NH_{ADD,DEL} events to the fib notification chain,
which notify capable devices when they should add or delete a nexthop
from their tables.This looks good -- thanks for doing this. IIUC the hardware forwarding use case for your hardware covered by David Ahern's patch[1] to the ipv4 software path selection is already covered, so this is probably the last known link/neighbor forwarding issue for ipv4 that needs coverage. 1. a6db449 net: ipv4: Consider failed nexthops in multipath routes
Cc: Roopa Prabhu <redacted> Cc: David Ahern <redacted> Cc: Andy Gospodarek <andy@greyhouse.net>
Reviewed-by Andy Gospodarek [off-list ref]
quoted hunk ↗ jump to hunk
Signed-off-by: Ido Schimmel <redacted> Signed-off-by: Jiri Pirko <redacted> --- include/net/ip_fib.h | 7 +++++++ net/ipv4/fib_semantics.c | 33 +++++++++++++++++++++++++++++++++ 2 files changed, 40 insertions(+)diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h index 57c2a86..45a184e 100644 --- a/include/net/ip_fib.h +++ b/include/net/ip_fib.h@@ -214,11 +214,18 @@ struct fib_entry_notifier_info { u32 nlflags; }; +struct fib_nh_notifier_info { + struct fib_notifier_info info; /* must be first */ + struct fib_nh *fib_nh; +}; + enum fib_event_type { FIB_EVENT_ENTRY_ADD, FIB_EVENT_ENTRY_DEL, FIB_EVENT_RULE_ADD, FIB_EVENT_RULE_DEL, + FIB_EVENT_NH_ADD, + FIB_EVENT_NH_DEL, }; int register_fib_notifier(struct notifier_block *nb,diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c index 6306a67..317026a 100644 --- a/net/ipv4/fib_semantics.c +++ b/net/ipv4/fib_semantics.c@@ -1355,6 +1355,36 @@ int fib_sync_down_addr(struct net_device *dev, __be32 local) return ret; } +static int call_fib_nh_notifiers(struct fib_nh *fib_nh, + enum fib_event_type event_type) +{ + struct in_device *in_dev = __in_dev_get_rtnl(fib_nh->nh_dev); + struct fib_nh_notifier_info info = { + .fib_nh = fib_nh, + }; + + switch (event_type) { + case FIB_EVENT_NH_ADD: + if (fib_nh->nh_flags & RTNH_F_DEAD) + break; + if (IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && + fib_nh->nh_flags & RTNH_F_LINKDOWN) + break; + return call_fib_notifiers(dev_net(fib_nh->nh_dev), event_type, + &info.info); + case FIB_EVENT_NH_DEL: + if ((IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && + fib_nh->nh_flags & RTNH_F_LINKDOWN) || + (fib_nh->nh_flags & RTNH_F_DEAD)) + return call_fib_notifiers(dev_net(fib_nh->nh_dev), + event_type, &info.info); + default: + break; + } + + return NOTIFY_DONE; +} + /* Event force Flags Description * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host@@ -1396,6 +1426,8 @@ int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force) nexthop_nh->nh_flags |= RTNH_F_LINKDOWN; break; } + call_fib_nh_notifiers(nexthop_nh, + FIB_EVENT_NH_DEL); dead++; } #ifdef CONFIG_IP_ROUTE_MULTIPATH@@ -1550,6 +1582,7 @@ int fib_sync_up(struct net_device *dev, unsigned int nh_flags) continue; alive++; nexthop_nh->nh_flags &= ~nh_flags; + call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD); } endfor_nexthops(fi) if (alive > 0) { --2.7.4