Hello,
On Fri, 8 Apr 2016, Chris Friesen wrote:
> For local routes that require a particular output interface we do not want
> to cache the result. Caching the result causes incorrect behaviour when
> there are multiple source addresses on the interface. The end result
> being that if the intended recipient is waiting on that interface for the
> packet he won't receive it because it will be delivered on the loopback
> interface and the IP_PKTINFO ipi_ifindex will be set to the loopback
> interface as well.
>
> This can be tested by running a program such as "dhcp_release" which
> attempts to inject a packet on a particular interface so that it is
> received by another program on the same board. The receiving process
> should see an IP_PKTINFO ipi_ifndex value of the source interface
> (e.g., eth1) instead of the loopback interface (e.g., lo). The packet
> will still appear on the loopback interface in tcpdump but the important
> aspect is that the CMSG info is correct.
>
> Sample dhcp_release command line:
>
> dhcp_release eth1 192.168.204.222 02:11:33:22:44:66
>
> Signed-off-by: Allain Legacy <allain.leg...@windriver.com>
> Signed off-by: Chris Friesen <chris.frie...@windriver.com>
Looks good to me.
Reviewed-by: Julian Anastasov <j...@ssi.bg>
> ---
> net/ipv4/route.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/net/ipv4/route.c b/net/ipv4/route.c
> index 02c6229..b050cf9 100644
> --- a/net/ipv4/route.c
> +++ b/net/ipv4/route.c
> @@ -2045,6 +2045,18 @@ static struct rtable *__mkroute_output(const struct
> fib_result *res,
> */
> if (fi && res->prefixlen < 4)
> fi = NULL;
> + } else if ((type == RTN_LOCAL) && (orig_oif != 0) &&
> + (orig_oif != dev_out->ifindex)) {
> + /* For local routes that require a particular output interface
> + * we do not want to cache the result. Caching the result
> + * causes incorrect behaviour when there are multiple source
> + * addresses on the interface, the end result being that if the
> + * intended recipient is waiting on that interface for the
> + * packet he won't receive it because it will be delivered on
> + * the loopback interface and the IP_PKTINFO ipi_ifindex will
> + * be set to the loopback interface as well.
> + */
> + fi = NULL;
> }
>
> fnhe = NULL;
Regards
--
Julian Anastasov <j...@ssi.bg>
