Since commit 2b760fcf5cfb ("ipv6: hook up exception table to store dst
cache"), route exceptions reside in a separate hash table, and won't be
found by walking the FIB, so they won't be dumped to userspace on a
RTM_GETROUTE message.
This causes 'ip -6 route list cache' and 'ip -6 route flush cache' to
have no function anymore:
# ip -6 route get fc00:3::1
fc00:3::1 via fc00:1::2 dev veth_A-R1 src fc00:1::1 metric 1024 expires 539sec
mtu 1400 pref medium
# ip -6 route get fc00:4::1
fc00:4::1 via fc00:2::2 dev veth_A-R2 src fc00:2::1 metric 1024 expires 536sec
mtu 1500 pref medium
# ip -6 route list cache
# ip -6 route flush cache
# ip -6 route get fc00:3::1
fc00:3::1 via fc00:1::2 dev veth_A-R1 src fc00:1::1 metric 1024 expires 520sec
mtu 1400 pref medium
# ip -6 route get fc00:4::1
fc00:4::1 via fc00:2::2 dev veth_A-R2 src fc00:2::1 metric 1024 expires 519sec
mtu 1500 pref medium
because iproute2 lists cached routes using RTM_GETROUTE, and flushes them
by listing all the routes, and deleting them with RTM_DELROUTE one by one.
Look up exceptions in the hash table associated with the current fib6_info
in rt6_dump_route(), and, if present and not expired, add them to the
dump.
Re-allow userspace to get FIB results by passing the RTM_F_CLONED flag as
filter, by reverting commit 08e814c9e8eb ("net/ipv6: Bail early if user
only wants cloned entries").
As we do this, we also have to honour this flag while filtering routes in
rt6_dump_route() and, if this filter effectively causes some results to be
discarded, by passing the NLM_F_DUMP_FILTERED flag back.
To flush cached routes, a procfs entry could be introduced instead: that's
how it works for IPv4. We already have a rt6_flush_exception() function
ready to be wired to it. However, this would not solve the issue for
listing, and wouldn't fix the issue with current and previous versions of
iproute2.
Reported-by: Jianlin Shi <ji...@redhat.com>
Fixes: 2b760fcf5cfb ("ipv6: hook up exception table to store dst cache")
Signed-off-by: Stefano Brivio <sbri...@redhat.com>
---
This will cause a non-trivial conflict with commit cc5c073a693f
("ipv6: Move exception bucket to fib6_nh") on net-next. I can submit
an equivalent patch against net-next, if it helps.
net/ipv6/ip6_fib.c | 7 ++-----
net/ipv6/route.c | 38 +++++++++++++++++++++++++++++++++++---
2 files changed, 37 insertions(+), 8 deletions(-)
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 008421b550c6..5be133565819 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -581,13 +581,10 @@ static int inet6_dump_fib(struct sk_buff *skb, struct
netlink_callback *cb)
} else if (nlmsg_len(nlh) >= sizeof(struct rtmsg)) {
struct rtmsg *rtm = nlmsg_data(nlh);
- arg.filter.flags = rtm->rtm_flags & (RTM_F_PREFIX|RTM_F_CLONED);
+ if (rtm->rtm_flags & RTM_F_PREFIX)
+ arg.filter.flags = RTM_F_PREFIX;
}
- /* fib entries are never clones */
- if (arg.filter.flags & RTM_F_CLONED)
- goto out;
-
w = (void *)cb->args[2];
if (!w) {
/* New dump:
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 848e944f07df..51f923b3ad26 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -4862,8 +4862,11 @@ int rt6_dump_route(struct fib6_info *rt, void *p_arg)
{
struct rt6_rtnl_dump_arg *arg = (struct rt6_rtnl_dump_arg *) p_arg;
struct fib_dump_filter *filter = &arg->filter;
+ struct rt6_exception_bucket *bucket;
unsigned int flags = NLM_F_MULTI;
+ struct rt6_exception *rt6_ex;
struct net *net = arg->net;
+ int i, err;
if (rt == net->ipv6.fib6_null_entry)
return 0;
@@ -4882,9 +4885,38 @@ int rt6_dump_route(struct fib6_info *rt, void *p_arg)
flags |= NLM_F_DUMP_FILTERED;
}
- return rt6_fill_node(net, arg->skb, rt, NULL, NULL, NULL, 0,
- RTM_NEWROUTE, NETLINK_CB(arg->cb->skb).portid,
- arg->cb->nlh->nlmsg_seq, flags);
+ if (!(filter->flags & RTM_F_CLONED)) {
+ err = rt6_fill_node(net, arg->skb, rt, NULL, NULL, NULL, 0,
+ RTM_NEWROUTE,
+ NETLINK_CB(arg->cb->skb).portid,
+ arg->cb->nlh->nlmsg_seq, flags);
+ if (err)
+ return err;
+ } else {
+ flags |= NLM_F_DUMP_FILTERED;
+ }
+
+ bucket = rcu_dereference(rt->rt6i_exception_bucket);
+ if (!bucket)
+ return 0;
+
+ for (i = 0; i < FIB6_EXCEPTION_BUCKET_SIZE; i++) {
+ hlist_for_each_entry(rt6_ex, &bucket->chain, hlist) {
+ if (rt6_check_expired(rt6_ex->rt6i))
+ continue;
+
+ err = rt6_fill_node(net, arg->skb, rt,
+ &rt6_ex->rt6i->dst,
+ NULL, NULL, 0, RTM_NEWROUTE,
+ NETLINK_CB(arg->cb->skb).portid,
+ arg->cb->nlh->nlmsg_seq, flags);
+ if (err)
+ return err;
+ }
+ bucket++;
+ }
+
+ return 0;
}
static int inet6_rtm_valid_getroute_req(struct sk_buff *skb,
--
2.20.1
