ipv6: fix the outgoing interface selection order in udpv6_sendmsg()
1.When no interface is specified in an IPV6_PKTINFO ancillary data
item, the interface specified in an IPV6_PKTINFO sticky optionis
is used.
RFC3542:
6.7. Summary of Outgoing Interface Selection
This document and [RFC-3493] specify various methods that affect the
selection of the packet's outgoing interface. This subsection
summarizes the ordering among those in order to ensure deterministic
behavior.
For a given outgoing packet on a given socket, the outgoing interface
is determined in the following order:
1. if an interface is specified in an IPV6_PKTINFO ancillary data
item, the interface is used.
2. otherwise, if an interface is specified in an IPV6_PKTINFO sticky
option, the interface is used.
Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 38390dd..84b1a29 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -793,6 +793,9 @@
if (!fl.oif)
fl.oif = sk->sk_bound_dev_if;
+ if (!fl.oif)
+ fl.oif = np->sticky_pktinfo.ipi6_ifindex;
+
if (msg->msg_controllen) {
opt = &opt_space;
memset(opt, 0, sizeof(struct ipv6_txoptions));
