net/ipv6: Move gateway validation into helper

Move existing code to validate nexthop into a helper. Follow on patch
adds support for nexthops marked with onlink, and this helper keeps
the complexity of ip6_route_info_create in check.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index aa4411c..bfd1a06 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2469,6 +2469,54 @@ static struct rt6_info *ip6_nh_lookup_table(struct net *net,
        return rt;
 }
 
+static int ip6_route_check_nh(struct net *net,
+                             struct fib6_config *cfg,
+                             struct net_device **_dev,
+                             struct inet6_dev **idev)
+{
+       const struct in6_addr *gw_addr = &cfg->fc_gateway;
+       struct net_device *dev = _dev ? *_dev : NULL;
+       struct rt6_info *grt = NULL;
+       int err = -EHOSTUNREACH;
+
+       if (cfg->fc_table) {
+               grt = ip6_nh_lookup_table(net, cfg, gw_addr);
+               if (grt) {
+                       if (grt->rt6i_flags & RTF_GATEWAY ||
+                           (dev && dev != grt->dst.dev)) {
+                               ip6_rt_put(grt);
+                               grt = NULL;
+                       }
+               }
+       }
+
+       if (!grt)
+               grt = rt6_lookup(net, gw_addr, NULL, cfg->fc_ifindex, 1);
+
+       if (!grt)
+               goto out;
+
+       if (dev) {
+               if (dev != grt->dst.dev) {
+                       ip6_rt_put(grt);
+                       goto out;
+               }
+       } else {
+               *_dev = dev = grt->dst.dev;
+               *idev = grt->rt6i_idev;
+               dev_hold(dev);
+               in6_dev_hold(grt->rt6i_idev);
+       }
+
+       if (!(grt->rt6i_flags & RTF_GATEWAY))
+               err = 0;
+
+       ip6_rt_put(grt);
+
+out:
+       return err;
+}
+
 static struct rt6_info *ip6_route_info_create(struct fib6_config *cfg,
                                              struct netlink_ext_ack *extack)
 {
@@ -2664,8 +2712,6 @@ static struct rt6_info *ip6_route_info_create(struct fib6_config *cfg,
                rt->rt6i_gateway = *gw_addr;
 
                if (gwa_type != (IPV6_ADDR_LINKLOCAL|IPV6_ADDR_UNICAST)) {
-                       struct rt6_info *grt = NULL;
-
                        /* IPv6 strictly inhibits using not link-local
                           addresses as nexthop address.
                           Otherwise, router will not able to send redirects.
@@ -2682,40 +2728,7 @@ static struct rt6_info *ip6_route_info_create(struct fib6_config *cfg,
                                goto out;
                        }
 
-                       if (cfg->fc_table) {
-                               grt = ip6_nh_lookup_table(net, cfg, gw_addr);
-
-                               if (grt) {
-                                       if (grt->rt6i_flags & RTF_GATEWAY ||
-                                           (dev && dev != grt->dst.dev)) {
-                                               ip6_rt_put(grt);
-                                               grt = NULL;
-                                       }
-                               }
-                       }
-
-                       if (!grt)
-                               grt = rt6_lookup(net, gw_addr, NULL,
-                                                cfg->fc_ifindex, 1);
-
-                       err = -EHOSTUNREACH;
-                       if (!grt)
-                               goto out;
-                       if (dev) {
-                               if (dev != grt->dst.dev) {
-                                       ip6_rt_put(grt);
-                                       goto out;
-                               }
-                       } else {
-                               dev = grt->dst.dev;
-                               idev = grt->rt6i_idev;
-                               dev_hold(dev);
-                               in6_dev_hold(grt->rt6i_idev);
-                       }
-                       if (!(grt->rt6i_flags & RTF_GATEWAY))
-                               err = 0;
-                       ip6_rt_put(grt);
-
+                       err = ip6_route_check_nh(net, cfg, &dev, &idev);
                        if (err)
                                goto out;
                }