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;
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index b551269..b61fa8b 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -483,6 +483,9 @@
&ireq->ir_v6_rmt_addr);
fl6->daddr = ireq->ir_v6_rmt_addr;
+ if (np->repflow && (ireq->pktopts != NULL))
+ fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));
+
skb_set_queue_mapping(skb, queue_mapping);
err = ip6_xmit(sk, skb, fl6, np->opt, np->tclass);
err = net_xmit_eval(err);
@@ -1018,7 +1021,8 @@
if (!isn) {
if (ipv6_opt_accepted(sk, skb) ||
np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
- np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
+ np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim ||
+ np->repflow) {
atomic_inc(&skb->users);
ireq->pktopts = skb;
}
@@ -1143,6 +1147,8 @@
newnp->mcast_oif = inet6_iif(skb);
newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
+ if (np->repflow)
+ newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
/*
* No need to charge this sock to the relevant IPv6 refcnt debug socks count
@@ -1223,6 +1229,8 @@
newnp->mcast_oif = inet6_iif(skb);
newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
+ if (np->repflow)
+ newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
/* Clone native IPv6 options from listening socket (if any)
@@ -1434,6 +1442,8 @@
np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
+ if (np->repflow)
+ np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
if (ipv6_opt_accepted(sk, opt_skb)) {
skb_set_owner_r(opt_skb, sk);
opt_skb = xchg(&np->pktoptions, opt_skb);