Greetings,
I use the IP_PKTINFO to detect ipi_ifindex from which the packet was
arrived, it used to work for local addresses also.
For local addresses ipi_ifindex always returned 1, but starting from
Linux 4.14 ip_ifindex began to return various values.
Example host configuration:
1: lo: 127.0.0.1
2: eth0: 192.168.3.45
3: eth1: 192.168.4.45
I use sendto() with addresses {127.0.0.1, 192.168.3.45 and
192.168.4.45}, call recvmsg() and than use standard procedure to get
ipi_ifindex, it shows results:
| ipi_ifindex | ipi_ifindex
sendto(address) | Linux ver < 4.14 | Linux ver >= 4.14
---------------------------------------------------------------
127.0.0.1 | 1 | 1
---------------------------------------------------------------
192.168.3.45 | 1 | 2
---------------------------------------------------------------
192.168.4.45 | 1 | 3
It seems that this behavior depends from commit:
net: ipv4: set orig_oif based on fib result for local traffic
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-4.14.y&id=839da4d98960bcc68e6b7b945b33ad3916ec1e92
I believe that ipi_ifindex for local addresses should be 1.
Is there a Bug for Linux >= 4.14 or is this a valid behavior?
************************
Thanks,
Damir Mansurov
dn...@oktetlabs.ru
