From: Francesco Ruggeri <fruggeri@arista.com>
Date: Thu, 31 Oct 2019 17:44:13 -0700
Subject: net: icmp: use input address in traceroute
Patch-mainline: v5.5-rc1
Git-commit: 2adf81c0f7b04f9f10e55f5634b1eb7e0a783276
References: bsc#1154353
Even with icmp_errors_use_inbound_ifaddr set, traceroute returns the
primary address of the interface the packet was received on, even if
the path goes through a secondary address. In the example:
1.0.3.1/24
---- 1.0.1.3/24 1.0.1.1/24 ---- 1.0.2.1/24 1.0.2.4/24 ----
|H1|--------------------------|R1|--------------------------|H2|
---- N1 ---- N2 ----
where 1.0.3.1/24 is R1's primary address on N1, traceroute from
H1 to H2 returns:
traceroute to 1.0.2.4 (1.0.2.4), 30 hops max, 60 byte packets
1 1.0.3.1 (1.0.3.1) 0.018 ms 0.006 ms 0.006 ms
2 1.0.2.4 (1.0.2.4) 0.021 ms 0.007 ms 0.007 ms
After applying this patch, it returns:
traceroute to 1.0.2.4 (1.0.2.4), 30 hops max, 60 byte packets
1 1.0.1.1 (1.0.1.1) 0.033 ms 0.007 ms 0.006 ms
2 1.0.2.4 (1.0.2.4) 0.011 ms 0.007 ms 0.007 ms
Original-patch-by: Bill Fenner <fenner@arista.com>
Signed-off-by: Francesco Ruggeri <fruggeri@arista.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
net/ipv4/icmp.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -682,7 +682,8 @@ void __icmp_send(struct sk_buff *skb_in,
dev = dev_get_by_index_rcu(net, inet_iif(skb_in));
if (dev)
- saddr = inet_select_addr(dev, 0, RT_SCOPE_LINK);
+ saddr = inet_select_addr(dev, iph->saddr,
+ RT_SCOPE_LINK);
else
saddr = 0;
rcu_read_unlock();