[IPV4]: Remove unsupported DNAT (RTCF_NAT and RTCF_NAT) in IPV4

- The DNAT (Destination NAT) is not implemented in IPV4.

- This patch remove the code which checks these flags
in net/ipv4/arp.c and net/ipv4/route.c.

The RTCF_NAT and RTCF_NAT should stay in the header (linux/in_route.h)
because they are used in DECnet.

Signed-off-by: Rami Rosen <ramirose@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 4 insertions, 5 deletions

diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 9eb6d3ab2977..46edf1c32a40 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -835,9 +835,8 @@ static int arp_process(struct sk_buff *skb)
                         }
                         goto out;
                 } else if (IN_DEV_FORWARD(in_dev)) {
-                        if ((rt->rt_flags&RTCF_DNAT) ||
-                            (addr_type == RTN_UNICAST  && rt->u.dst.dev != dev &&
-                             (arp_fwd_proxy(in_dev, rt) || pneigh_lookup(&arp_tbl, &init_net, &tip, dev, 0)))) {
+                            if (addr_type == RTN_UNICAST  && rt->u.dst.dev != dev &&
+                             (arp_fwd_proxy(in_dev, rt) || pneigh_lookup(&arp_tbl, &init_net, &tip, dev, 0))) {
                                 n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
                                 if (n)
                                         neigh_release(n);
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 933b093721ea..78c4ce424a68 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1768,7 +1768,7 @@ static inline int __mkroute_input(struct sk_buff *skb,
         if (err)
                 flags |= RTCF_DIRECTSRC;
 
-        if (out_dev == in_dev && err && !(flags & (RTCF_NAT | RTCF_MASQ)) &&
+        if (out_dev == in_dev && err && !(flags & RTCF_MASQ) &&
             (IN_DEV_SHARED_MEDIA(out_dev) ||
              inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
                 flags |= RTCF_DOREDIRECT;
@@ -1777,7 +1777,7 @@ static inline int __mkroute_input(struct sk_buff *skb,
                 /* Not IP (i.e. ARP). Do not create route, if it is
                  * invalid for proxy arp. DNAT routes are always valid.
                  */
-                if (out_dev == in_dev && !(flags & RTCF_DNAT)) {
+                if (out_dev == in_dev) {
                         err = -EINVAL;
                         goto cleanup;
                 }