From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wei Zhang Subject: [PATCH] net: fix incorrect original ingress device index in PKTINFO Date: Tue, 27 Dec 2016 17:52:24 +0800 Message-ID: <1482832344-24760-1-git-send-email-asuka.com@163.com> Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: davem@davemloft.net, kuznet@ms2.inr.ac.ru, jmorris@namei.org, yoshfuji@linux-ipv6.org, kaber@trash.net Return-path: Received: from m12-16.163.com ([220.181.12.16]:47283 "EHLO m12-16.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752752AbcL0JyD (ORCPT ); Tue, 27 Dec 2016 04:54:03 -0500 Sender: netdev-owner@vger.kernel.org List-ID: When we send a packet for our own local address on a non-loopback interface (e.g. eth0), due to the change had been introduced from commit 0b922b7a829c ("net: original ingress device index in PKTINFO"), the original ingress device index would be set as the loopback interface. However, the packet should be considered as if it is being arrived via the sending interface (eth0), otherwise it would break the expectation of the userspace application (e.g. the DHCPRELEASE message from dhcp_release binary would be ignored by the dnsmasq daemon, since it come from lo which is not the interface dnsmasq bind to) Signed-off-by: Wei Zhang --- net/ipv4/ip_sockglue.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index b8a2d63..76d78a7 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -1202,8 +1202,14 @@ void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb) * which has interface index (iif) as the first member of the * underlying inet{6}_skb_parm struct. This code then overlays * PKTINFO_SKB_CB and in_pktinfo also has iif as the first - * element so the iif is picked up from the prior IPCB + * element so the iif is picked up from the prior IPCB except + * iif is loopback interface which the packet should be + * considered as if it is being arrived via the sending + * interface */ + if (pktinfo->ipi_ifindex == LOOPBACK_IFINDEX) + pktinfo->ipi_ifindex = inet_iif(skb); + pktinfo->ipi_spec_dst.s_addr = fib_compute_spec_dst(skb); } else { pktinfo->ipi_ifindex = 0; -- 1.8.3.1