ipv6: add the IPV6_FL_F_REFLECT flag to IPV6_FL_A_GET
With this option, the socket will reply with the flow label value read
on received packets.
The goal is to have a connection with the same flow label in both
direction of the communication.
Changelog of V4:
* Do not erase the flow label on the listening socket. Use pktopts to
store the received value
Signed-off-by: Florent Fourcot <florent.fourcot@enst-bretagne.fr>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c
index cbc9351..55823f1 100644
--- a/net/ipv6/ip6_flowlabel.c
+++ b/net/ipv6/ip6_flowlabel.c
@@ -486,6 +486,11 @@
struct ipv6_pinfo *np = inet6_sk(sk);
struct ipv6_fl_socklist *sfl;
+ if (np->repflow) {
+ freq->flr_label = np->flow_label;
+ return 0;
+ }
+
rcu_read_lock_bh();
for_each_sk_fl_rcu(np, sfl) {
@@ -527,6 +532,15 @@
switch (freq.flr_action) {
case IPV6_FL_A_PUT:
+ if (freq.flr_flags & IPV6_FL_F_REFLECT) {
+ if (sk->sk_protocol != IPPROTO_TCP)
+ return -ENOPROTOOPT;
+ if (!np->repflow)
+ return -ESRCH;
+ np->flow_label = 0;
+ np->repflow = 0;
+ return 0;
+ }
spin_lock_bh(&ip6_sk_fl_lock);
for (sflp = &np->ipv6_fl_list;
(sfl = rcu_dereference(*sflp))!=NULL;
@@ -567,6 +581,13 @@
return -ESRCH;
case IPV6_FL_A_GET:
+ if (freq.flr_flags & IPV6_FL_F_REFLECT) {
+ if (sk->sk_protocol != IPPROTO_TCP)
+ return -ENOPROTOOPT;
+ np->repflow = 1;
+ return 0;
+ }
+
if (freq.flr_label & ~IPV6_FLOWLABEL_MASK)
return -EINVAL;