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Miller" , Chris J Arges , Daniel Zahka , David Ahern , David Wei , Dimitri Daskalakis , Donald Hunter , Eric Dumazet , Ido Schimmel , Jakub Kicinski , Paolo Abeni , Shuah Khan , Simon Horman , Stanislav Fomichev , Willem de Bruijn , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH net-next v6 03/10] ipv6: record the reason for kernel-initiated route deletions Date: Sat, 8 Aug 2026 09:56:35 +0900 Message-ID: <20260808005642.26901-4-sigefriedhyy@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260808005642.26901-1-sigefriedhyy@gmail.com> References: <20260808005642.26901-1-sigefriedhyy@gmail.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Record why the kernel deletes an IPv6 route on its own: - RT_DEL_REASON_EXPIRED for routes reaped by the FIB6 garbage collector after their RTF_EXPIRES lifetime ran out. - RT_DEL_REASON_RA_WITHDRAWN for default routes, prefix routes and RFC 4191 route information routes withdrawn by a zero-lifetime Router Advertisement. Deleting a default route because its metric changed is not a withdrawal, so it keeps RT_DEL_REASON_UNSPEC. Signed-off-by: Yuyang Huang Reviewed-by: Ido Schimmel --- net/ipv6/addrconf.c | 3 ++- net/ipv6/ip6_fib.c | 2 +- net/ipv6/ndisc.c | 4 +++- net/ipv6/route.c | 2 +- 4 files changed, 7 insertions(+), 4 deletions(-) diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index f6fa2715b450..9d89be7e0544 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -2874,7 +2874,8 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao) if (rt) { /* Autoconf prefix route */ if (valid_lft == 0) { - ip6_del_rt(net, rt, false); + ip6_del_rt_reason(net, rt, + RT_DEL_REASON_RA_WITHDRAWN); rt = NULL; } else { table = rt->fib6_table; diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index 1f6f6f33ded1..f8a9ec7fa616 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -2403,7 +2403,7 @@ static void fib6_gc_table(struct net *net, hlist_for_each_entry_safe(rt, n, &tb6->tb6_gc_hlist, gc_link) if (fib6_age(rt, gc_args) == -1) - fib6_del(rt, &info, RT_DEL_REASON_UNSPEC); + fib6_del(rt, &info, RT_DEL_REASON_EXPIRED); } static void fib6_gc_all(struct net *net, struct fib6_gc_args *gc_args) diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c index fe36b3f51285..1111c4ebc61d 100644 --- a/net/ipv6/ndisc.c +++ b/net/ipv6/ndisc.c @@ -1361,7 +1361,9 @@ static enum skb_drop_reason ndisc_router_discovery(struct sk_buff *skb) defrtr_usr_metric = in6_dev->cnf.ra_defrtr_metric; /* delete the route if lifetime is 0 or if metric needs change */ if (rt && (lifetime == 0 || rt->fib6_metric != defrtr_usr_metric)) { - ip6_del_rt(net, rt, false); + ip6_del_rt_reason(net, rt, + lifetime == 0 ? RT_DEL_REASON_RA_WITHDRAWN : + RT_DEL_REASON_UNSPEC); rt = NULL; } diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 252f1825a199..bb14d7f7bad4 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -1020,7 +1020,7 @@ int rt6_route_rcv(struct net_device *dev, u8 *opt, int len, gwaddr, dev); if (rt && !lifetime) { - ip6_del_rt(net, rt, false); + ip6_del_rt_reason(net, rt, RT_DEL_REASON_RA_WITHDRAWN); rt = NULL; } -- 2.43.0