[IPV4] LVS: Allow to send ICMP unreachable responses when real-servers are removed

this is a small patch by Janusz Krzysztofik to ip_route_output_slow()
that allows VIP-less LVS linux director to generate packets
originating >From VIP if sysctl_ip_nonlocal_bind is set.

In a nutshell, the intention is for an LVS linux director to be able
to send ICMP unreachable responses to end-users when real-servers are
removed.

http://archive.linuxvirtualserver.org/html/lvs-users/2007-01/msg00106.html

Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index df9fe4f2e8cc5df95fc43c3fe1c271d8d480ac89..cb76e3c725a08581b7b0d1b62841bfb0ca775d04 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2396,7 +2396,7 @@ static int ip_route_output_slow(struct rtable **rp, const struct flowi *oldflp)
 
                /* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
                dev_out = ip_dev_find(oldflp->fl4_src);
-               if (dev_out == NULL)
+               if ((dev_out == NULL) && !(sysctl_ip_nonlocal_bind))
                        goto out;
 
                /* I removed check for oif == dev_out->oif here.
@@ -2407,7 +2407,7 @@ static int ip_route_output_slow(struct rtable **rp, const struct flowi *oldflp)
                      of another iface. --ANK
                 */
 
-               if (oldflp->oif == 0
+               if (dev_out && oldflp->oif == 0
                    && (MULTICAST(oldflp->fl4_dst) || oldflp->fl4_dst == htonl(0xFFFFFFFF))) {
                        /* Special hack: user can direct multicasts
                           and limited broadcast via necessary interface