ipv4 05/05: add sysctl to accept packets with local source addresses

commit 8ec1e0ebe26087bfc5c0394ada5feb5758014fc8
Author: Patrick McHardy <kaber@trash.net>
Date:   Thu Dec 3 12:16:35 2009 +0100

    ipv4: add sysctl to accept packets with local source addresses

    Change fib_validate_source() to accept packets with a local source address when
    the "accept_local" sysctl is set for the incoming inet device. Combined with the
    previous patches, this allows to communicate between multiple local interfaces
    over the wire.

    Signed-off-by: Patrick McHardy <kaber@trash.net>

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 8 insertions, 4 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index c100709d6dd..e3126612fcb 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1468,6 +1468,7 @@ static struct devinet_sysctl_table {
                 DEVINET_SYSCTL_RW_ENTRY(SEND_REDIRECTS, "send_redirects"),
                 DEVINET_SYSCTL_RW_ENTRY(ACCEPT_SOURCE_ROUTE,
                                         "accept_source_route"),
+                DEVINET_SYSCTL_RW_ENTRY(ACCEPT_LOCAL, "accept_local"),
                 DEVINET_SYSCTL_RW_ENTRY(PROXY_ARP, "proxy_arp"),
                 DEVINET_SYSCTL_RW_ENTRY(MEDIUM_ID, "medium_id"),
                 DEVINET_SYSCTL_RW_ENTRY(BOOTP_RELAY, "bootp_relay"),
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 3b373a8b047..3323168ee52 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -241,16 +241,17 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
                             .iif = oif };
 
         struct fib_result res;
-        int no_addr, rpf;
+        int no_addr, rpf, accept_local;
         int ret;
         struct net *net;
 
-        no_addr = rpf = 0;
+        no_addr = rpf = accept_local = 0;
         rcu_read_lock();
         in_dev = __in_dev_get_rcu(dev);
         if (in_dev) {
                 no_addr = in_dev->ifa_list == NULL;
                 rpf = IN_DEV_RPFILTER(in_dev);
+                accept_local = IN_DEV_ACCEPT_LOCAL(in_dev);
         }
         rcu_read_unlock();
 
@@ -260,8 +261,10 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
         net = dev_net(dev);
         if (fib_lookup(net, &fl, &res))
                 goto last_resort;
-        if (res.type != RTN_UNICAST)
-                goto e_inval_res;
+        if (res.type != RTN_UNICAST) {
+                if (res.type != RTN_LOCAL || !accept_local)
+                        goto e_inval_res;
+        }
         *spec_dst = FIB_RES_PREFSRC(res);
         fib_combine_itag(itag, &res);
 #ifdef CONFIG_IP_ROUTE_MULTIPATH