# \[PATCH 3/3\]ipv6:fix the outgoing interface selection order in udpv6\_sendmsg() - From: Yang Hongyang \ - Date: 2008-08-29 07:40:47 - List: netdev - Page: https://ratatoskr.run/netdev/2008/08/10806872 - Thread: https://ratatoskr.run/netdev/2008/08/10806872/t.md ```text 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 --- net/ipv6/udp.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index a6aecf7..e553ab7 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -733,6 +733,9 @@ do_udp_sendmsg: } if (!fl.oif) + fl.oif = np->sticky_pktinfo.ipi6_ifindex; + + if (!fl.oif) fl.oif = sk->sk_bound_dev_if; if (msg->msg_controllen) { -- 1.5.3.8 ```