[PATCH net] ipv6: Fix getsockopt() for sockets with default IPV6_AUTOFLOWLABEL

[Ben Hutchings]

Commit 513674b5a2c9 ("net: reevalulate autoflowlabel setting after
sysctl setting") removed the initialisation of
ipv6_pinfo::autoflowlabel and added a second flag to indicate
whether this field or the net namespace default should be used.

The getsockopt() handling for this case was not updated, so it
currently returns 0 for all sockets for which IPV6_AUTOFLOWLABEL is
not explicitly enabled.  Fix it to return the effective value, whether
that has been set at the socket or net namespace level.

Fixes: 513674b5a2c9 ("net: reevalulate autoflowlabel setting after sysctl ...")
Signed-off-by: Ben Hutchings <ben.hutchi...@codethink.co.uk>
---
This will need to go to stable, as the earlier commit did.

Ben.

 include/net/ipv6.h       | 1 +
 net/ipv6/ip6_output.c    | 2 +-
 net/ipv6/ipv6_sockglue.c | 2 +-
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index f73797e2fa60..221238254eb7 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -331,6 +331,7 @@ int ipv6_flowlabel_opt_get(struct sock *sk, struct 
in6_flowlabel_req *freq,
                           int flags);
 int ip6_flowlabel_init(void);
 void ip6_flowlabel_cleanup(void);
+bool ip6_autoflowlabel(struct net *net, const struct ipv6_pinfo *np);
 
 static inline void fl6_sock_release(struct ip6_flowlabel *fl)
 {
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 688ba5f7516b..08446e0ca411 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -166,7 +166,7 @@ int ip6_output(struct net *net, struct sock *sk, struct 
sk_buff *skb)
                            !(IP6CB(skb)->flags & IP6SKB_REROUTED));
 }
 
-static bool ip6_autoflowlabel(struct net *net, const struct ipv6_pinfo *np)
+bool ip6_autoflowlabel(struct net *net, const struct ipv6_pinfo *np)
 {
        if (!np->autoflowlabel_set)
                return ip6_default_np_autolabel(net);
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 2d4680e0376f..e8ffb5b5d84e 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -1336,7 +1336,7 @@ static int do_ipv6_getsockopt(struct sock *sk, int level, 
int optname,
                break;
 
        case IPV6_AUTOFLOWLABEL:
-               val = np->autoflowlabel;
+               val = ip6_autoflowlabel(sock_net(sk), np);
                break;
 
        case IPV6_RECVFRAGSIZE:
-- 
2.15.0.rc0