From 0c5fcf9e249ee1d94cf872c99baf9cba7ff9ce27 Mon Sep 17 00:00:00 2001 From: Amit Cohen Date: Sun, 7 Feb 2021 10:22:52 +0200 Subject: IPv6: Add "offload failed" indication to routes After installing a route to the kernel, user space receives an acknowledgment, which means the route was installed in the kernel, but not necessarily in hardware. The asynchronous nature of route installation in hardware can lead to a routing daemon advertising a route before it was actually installed in hardware. This can result in packet loss or mis-routed packets until the route is installed in hardware. To avoid such cases, previous patch set added the ability to emit RTM_NEWROUTE notifications whenever RTM_F_OFFLOAD/RTM_F_TRAP flags are changed, this behavior is controlled by sysctl. With the above mentioned behavior, it is possible to know from user-space if the route was offloaded, but if the offload fails there is no indication to user-space. Following a failure, a routing daemon will wait indefinitely for a notification that will never come. This patch adds an "offload_failed" indication to IPv6 routes, so that users will have better visibility into the offload process. 'struct fib6_info' is extended with new field that indicates if route offload failed. Note that the new field is added using unused bit and therefore there is no need to increase struct size. Signed-off-by: Amit Cohen Signed-off-by: Ido Schimmel Signed-off-by: David S. Miller --- net/ipv6/route.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'net/ipv6') diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 0d1784b0d65d..bc75b705f54b 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -5619,6 +5619,8 @@ static int rt6_fill_node(struct net *net, struct sk_buff *skb, rtm->rtm_flags |= RTM_F_OFFLOAD; if (rt->trap) rtm->rtm_flags |= RTM_F_TRAP; + if (rt->offload_failed) + rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED; } if (rtnl_put_cacheinfo(skb, dst, 0, expires, dst ? dst->error : 0) < 0) @@ -6070,16 +6072,18 @@ errout: } void fib6_info_hw_flags_set(struct net *net, struct fib6_info *f6i, - bool offload, bool trap) + bool offload, bool trap, bool offload_failed) { struct sk_buff *skb; int err; - if (f6i->offload == offload && f6i->trap == trap) + if (f6i->offload == offload && f6i->trap == trap && + f6i->offload_failed == offload_failed) return; f6i->offload = offload; f6i->trap = trap; + f6i->offload_failed = offload_failed; if (!rcu_access_pointer(f6i->fib6_node)) /* The route was removed from the tree, do not send -- cgit v1.2.3-58-ga151