blob: 1a465b2b57eae2d548d6fd8af40ad3f75452e904 [file] [log] [blame]
From 4b70d3092ce687fb903a901f6a20ff94b6a29048 Mon Sep 17 00:00:00 2001
From: Wei Zhang <asuka.com@163.com>
Date: Thu, 29 Dec 2016 16:45:04 +0800
Subject: [PATCH] net: fix incorrect original ingress device index in PKTINFO
commit f0c16ba8933ed217c2688b277410b2a37ba81591 upstream.
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)
Fixes: 0b922b7a829c ("net: original ingress device index in PKTINFO")
Acked-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: Wei Zhang <asuka.com@163.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 4964d1bdb390..193ee7ba3e22 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -1199,8 +1199,14 @@ 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. If iif
+ * is the loopback interface, then return the sending interface
+ * (e.g., process binds socket to eth0 for Tx which is
+ * redirected to loopback in the rtable/dst).
*/
+ 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;
--
2.10.1