| Message ID | 5707C950.6060806@windriver.com |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
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.legacy@windriver.com> > Signed off-by: Chris Friesen <chris.friesen@windriver.com> > --- > net/ipv4/route.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/net/ipv4/route.c b/net/ipv4/route.c > index 02c6229..437a377 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, Your patch is corrupted. I was in the same trap some time ago but with different client: From Documentation/email-clients.txt: Don't send patches with "format=flowed". This can cause unexpected and unwanted line breaks. Anyways, the change looks good to me and I'll add my Reviewed-by tag the next time. > */ > 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 <ja@ssi.bg>
On 04/08/2016 01:14 PM, Julian Anastasov wrote: > Your patch is corrupted. I was in the same trap > some time ago but with different client: > > From Documentation/email-clients.txt: > > Don't send patches with "format=flowed". This can cause unexpected > and unwanted line breaks. > > Anyways, the change looks good to me and I'll add my > Reviewed-by tag the next time. Doh...forgot to turn off word wrapping. New patch coming. Chris
diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 02c6229..437a377 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; }
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.legacy@windriver.com> Signed off-by: Chris Friesen <chris.friesen@windriver.com> --- net/ipv4/route.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) fnhe = NULL;